Updated on 2024/10/08

写真a

 
OKADA, Junichi
 
Affiliation
Faculty of Sport Sciences, School of Sport and Sciences
Job title
Professor
Degree
博士(スポーツ科学) ( 早稲田大学 )

Research Experience

  • 1992
    -
    1994

    Japan Amateur Sports Association, Sports Science Laboratory, Researcher

Professional Memberships

  •  
     
     

    日本スポーツ方法学会

  •  
     
     

    日本トレーニング学会

  •  
     
     

    National Strength and Conditioning Association Japan

  •  
     
     

    日本体力医学会

  •  
     
     

    日本体育学会

Research Areas

  • Sports sciences

Research Interests

  • Sports Science

Awards

  • Japan Strength and Conditioning Association, Research Award

    2009.06  

  • 秩父宮記念スポーツ医・科学賞奨励賞(スポーツ栄養研究プロジェクトグループ)

    2001.06  

 

Papers

  • Differences in muscle synergies between skilled and unskilled athletes in power clean exercise at various loads

    Nadaka Hakariya, Benio Kibushi, Junichi Okada

    Journal of Sports Sciences     1 - 10  2023.09  [Refereed]

    Authorship:Last author

    DOI

    Scopus

  • Validity of using perceived exertion to assess muscle fatigue during bench press exercise

    Hanye Zhao, Dasom Seo, Junichi Okada

    Isokinetics and Exercise Science     1 - 11  2023.08  [Refereed]

    Authorship:Last author

     View Summary

    BACKGROUND: Muscle fatigue is nearly unavoidable during resistance exercise, yet evaluating it in such circumstances can be challenging. OBJECTIVE: This study aimed to evaluate the validity of using the rating of perceived exertion (RPE) as a measure of muscle fatigue during non-explosive bench press (BP) exercise. METHODS: Fifteen male collegiate athletes participated in three BP tasks set at 65% of their one-repetition maximum. The RPE, spectral fatigue index (SFI), and velocity loss were measured across different experimental conditions. RESULTS: Significant effects were observed across different experimental conditions for the overall RPE, average velocity loss, and average SFI (all p< 0.001). As the lifting tasks progressed, there were significant increases in the RPE, velocity loss, and SFI (p< 0.001). Additionally, significant differences were observed between the experimental conditions in the RPE (p< 0.001), SFI (p< 0.001), and velocity loss (p< 0.01). A significantly stronger (p< 0.05) correlation was observed between the RPE and SFI (r= 0.68, df= 117, p< 0.001) than between the velocity loss and SFI (r= 0.51, df= 117, p< 0.001). CONCLUSIONS: The corresponding changes observed in the RPE, velocity loss, and SFI suggest that both the RPE and velocity loss can be used as indicators of muscle fatigue during non-explosive BP exercise. However, due to the strong correlation between the RPE and SFI, RPE is more effective for reflecting muscle fatigue in non-explosive resistance exercise settings. Regarding ease of use, the RPE is more suitable than velocity loss for assessing muscle fatigue in training scenarios.

    DOI

  • Ballistic Exercise Versus Heavy Resistance Exercise Protocols: Which Resistance Priming Is More Effective for Improving Neuromuscular Performance on the Following Day?

    Takuya Nishioka, Junichi Okada

    Journal of Strength and Conditioning Research   Publish Ahead of Print ( 10 ) 1939 - 1946  2023.03  [Refereed]

    Authorship:Last author

     View Summary

    ABSTRACT: Nishioka, T and Okada, J. Ballistic exercise versus heavy resistance exercise protocols: which resistance priming is more effective for improving neuromuscular performance on the following day? J Strength Cond Res 37(10): 1939-1946, 2023-This study aimed to determine whether ballistic exercise priming (BEP) or heavy resistance priming (HRP) is more effective for improving ballistic performance after 24 hours. Ten resistance-trained men performed BEP and HRP conditions 72-144 hours apart in a randomized and counterbalanced order. Jumping performance was assessed before and 24 hours after the BEP and HRP sessions using 0 and 40% one-repetition maximum (1RM) squat jump (SJ), 0 and 40% 1RM countermovement jump (CMJ), and drop jump (DJ) reactive strength index (RSI). Statistical significance was accepted at p ≤ 0.05. In the BEP condition, 0% 1RM CMJ height (+3.62%) as well as theoretical maximum velocity (+5.14%) and theoretical maximum power (+2.55%) obtained from CMJ 24 hours after the priming session were significantly greater than those at the baseline ( p ≤ 0.05), but 0% 1RM SJ height and DJ RSI ( p > 0.05) were not greater than those at the baseline. In the HRP condition, the jump performances were not improved ( p > 0.05). The percentage change in 0% 1RM CMJ height in the BEP condition was significantly greater than that seen in the HRP condition ( p = 0.015) but did not differ for 0% 1RM SJ height and DJ RSI ( p > 0.05). These results suggest that the BEP is more effective than HRP in improving CMJ performance after 24 hours. Therefore, practitioners should consider prescribing resistance priming using low-load ballistic exercises rather than high-load traditional exercises when planning to enhance athlete performance on the following day.

    DOI PubMed

  • Validity of using perceived exertion to assess muscle fatigue during back squat exercise

    Hanye Zhao, Dasom Seo, Junichi Okada

    BMC Sports Science, Medicine and Rehabilitation   15 ( 1 )  2023.02  [Refereed]

    Authorship:Last author

     View Summary

    The rating of perceived exertion (RPE) scale has been found to reflect physiological responses, and this study aimed to assess the validity of using the Borg CR-10 scale and velocity loss to evaluate muscle fatigue quantified by surface electromyography during back squat (BS) exercise. A total of 15 collegiate male athletes underwent three non-explosive BS tasks comprising low, medium, and high volumes at 65% of their one-repetition maximum. RPEs, spectral fatigue index (SFI), and velocity loss during BS exercise were assessed throughout the trials. Significant differences in overall RPE (p < 0.001) and average SFI (p < 0.05) were observed between the conditions, whereas no significant difference was observed in average velocity loss. Significant increases in RPE and SFI (p < 0.001) were observed within the exercise process, whereas a significant increase in velocity loss was not observed. Correlation analyses indicated a significant correlation between RPE and SFI obtained during exercise (r = 0.573, p < 0.001). However, no significant correlation was observed between velocity loss and SFI. These results demonstrated that RPE could be used as a muscle fatigue predictor in BS exercise, but that velocity loss may not reflect muscle fatigue correctly when participants cannot and/or are not required to perform BS explosively. Furthermore, practitioners should not use velocity loss as a muscle fatigue indicator in some resistance exercise situations, such as rehabilitation, beginner, and hypertrophy programs.

    DOI

    Scopus

    9
    Citation
    (Scopus)
  • Associations of maximum and reactive strength indicators with force–velocity profiles obtained from squat jump and countermovement jump

    Takuya Nishioka, Junichi Okada

    PLOS ONE   17 ( 10 ) e0276681 - e0276681  2022.10  [Refereed]

    Authorship:Last author

     View Summary

    Understanding the properties associated with the vertical force–velocity (F–v) profiles is important for maximizing jump performance. The purpose of this study was to evaluate the associations of maximum and reactive strength indicators with the F–v profiles obtained from squat jump (SJ) and countermovement jump (CMJ). On the first day, 20 resistance-trained men underwent measurements for half squat (HSQ) one-repetition maximum (1RM). On the second day, jump performances were measured to calculate the drop jump (DJ) reactive strength index (RSI) and the parameters of F–v profiles (theoretical maximum force [F0], velocity [V0], power [Pmax], and slope of the linear F–v relationship [SFv]) obtained from SJ and CMJ. The DJ RSI was not significantly correlated with any parameter of the vertical F–v profiles, whereas the relative HSQ 1RM was significantly correlated with the SJ F0 (r = 0.508, p = 0.022), CMJ F0 (r = 0.499, p = 0.025), SJ SFv (r = −0.457, p = 0.043), and CMJ Pmax (r = 0.493, p = 0.027). These results suggest that maximum strength is a more important indicator than reactive strength in improving vertical F–v profiles. Furthermore, the importance of maximum strength may vary depending on whether the practitioner wants to maximize the performance of SJ or CMJ.

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Auditory sEMG biofeedback for reducing muscle co-contraction during pedaling

    Kibushi B, Okada J

    Physiological Reports    2022.05  [Refereed]

    DOI

    Scopus

    2
    Citation
    (Scopus)
  • Validity of using perceived exertion to assess muscle fatigue during resistance exercises

    Zhao H, Nishioka T, Okada J

    PeerJ   10   e13019  2022.03  [Refereed]  [International journal]

    Authorship:Last author

     View Summary

    BACKGROUND: The rating of perceived exertion (RPE) is correlated with physiological variables. The purpose of this study was to assess the validity of using the Borg CR-10 scale and velocity to predict muscle fatigue assessed by surface electromyography during single joint resistance exercises. METHODS: Fifteen healthy males underwent different fatigue levels of unilateral elbow flexion (EF) and knee extension (KE), consisting of low, medium, and high volumes at 65% of their one-repetition maximum. The RPEs, spectral fatigue index (SFI), and mean velocity of the experimental exercises were assessed throughout the trials. RESULTS: Significant differences in overall RPE (p < 0.001) and average SFI (p < 0.001) were observed between the conditions in both exercises. Significant changes in RPE and SFI (p < 0.001) were observed throughout the EF, whereas a SFI increase (p < 0.001) was only observed at the end point of KE. Multiple regression analyses revealed two significant models (p < 0.001) for the prediction of muscle fatigue during EF (R2 = 0.552) and KE (R2 = 0.377). CONCLUSIONS: Muscle fatigue resulted in similar increases in perceptual responses, demonstrating that RPE is useful for assessing fatigue when resistance exercise is performed. However, velocity changes may not reflect muscle fatigue correctly when exercise is no longer performed in an explosive manner. We recommend combining RPE responses with velocity changes to comprehensively assess muscle fatigue during clinical and sports situations.

    DOI PubMed

    Scopus

    17
    Citation
    (Scopus)
  • Influence of Strength Level on Performance Enhancement Using Resistance Priming

    Nishioka T, Okada J

    The Journal of Strength and Conditioning Research   36 ( 1 ) 37 - 46  2022  [Refereed]

    Authorship:Last author

    DOI

    Scopus

    14
    Citation
    (Scopus)
  • Comparison of the Power Output Between the Hang Power Clean and Hang High Pull Across a Wide Range of Loads in Weightlifters

    Seiichiro Takei, Kuniaki Hirayama, Junichi Okada

    Journal of Strength and Conditioning Research   35 ( 1 ) S84 - S88  2021.02  [Refereed]

    Authorship:Last author

    DOI

  • N-terminal fragments of titin in urine as a biomarker for eccentric exercise-induced muscle damage

    Shota Yamaguchi, Katsuhiko Suzuki, Kazue Kanda, Junichi Okada

    The Journal of Physical Fitness and Sports Medicine   9 ( 1 ) 21 - 29  2020.01  [Refereed]

    DOI

  • Changes in urinary titin N-terminal fragment concentration after concentric and eccentric exercise

    Yamaguchi S, Suzuki K, Inami T, Kanda K, Zhao H, Okada J

    Journal of Sports Science and Medicine   19 ( 1 ) 121 - 129  2020  [Refereed]  [International journal]

     View Summary

    We aimed to compare the urinary titin N-terminal fragment (UTF) concentration after concentric and eccentric exercise and to clarify the specific response of UTF to exercise-induced muscle damage (EIMD). Nine healthy young men performed 30 concentric elbow flexion exercises with maximum effort, rested for at least eight weeks, and performed eccentric exercises at the same workload using the same arm. Changes in the maximal voluntary isometric contraction (MVIC), muscle soreness (SOR), range of motion (ROM), serum creatine kinase (CK) activity, and UTF concentrations were recorded before and after for six consecutive days after exercise. There was no significant difference in workload during exercise between the two exercise types. However, serum CK activity increased after eccentric exercise (p < 0.05). Additionally, MVIC, SOR, ROM, and UTF concentration were significantly higher after eccentric exercise than after concentric exercise (p < 0.05). Although workload was the same, the UTF concentration greatly increased after eccentric exercise. Based on these results, we suggest that UTF can be a non-invasive and highly specific biomarker of EIMD.

    PubMed

  • Effects of rest interval array on training volume, perceived exertion, neuromuscular fatigue, and metabolic responses during agonist-antagonist muscle alternative training

    ZHAO H, YAMAGUCHI S, OKADA J

    The Journal of Sports Medicine and Physical Fitness   60 ( 4 ) 536 - 543  2020  [Refereed]  [International journal]

     View Summary

    BACKGROUND: Agonist-antagonist muscle superset (SS) and paired-set (PS) strength training protocols enable the completion of training activities within a shorter period of time than traditional set. The purpose of this study was to investigate the effects of PS and SS through total volume (TV), set volume (SV), blood lactate concentration (LAC), rating of perceived exertion (RPE), and neuromuscular fatigue index (FInsm5). METHODS: Eleven males who train recreationally performed PS and SS consisting of bent-over row (BOR) and bench press (BP). In performing the PS, a single bout of BOR was followed by a rest interval of 60 seconds, the BP was then performed and followed by another rest interval of 60 seconds. When the SS was performed, a single bout of BOR and a single bout of BP were performed consecutively and followed by a single rest interval of 120 seconds. The exercise configurations were repeated until five sets were completed. The TV was calculated by multiplying the number of successful repetitions and the load. The LAC and RPE were measured at predetermined times. Electromyographic signals were recorded for use in the FInsm5 calculation. RESULTS: The RPE indicated that PS was significantly lower than SS (P<0.01). No significant differences between PS and SS were discovered in SV, TV, LAC, and FInsm5. CONCLUSIONS: This study demonstrates that PS has lower perceived exertion than SS when agonist-antagonist strength training protocols are selected as the training structure.

    DOI PubMed

    Scopus

    1
    Citation
    (Scopus)
  • Changes in urinary titin N-terminal fragments as a biomarker of exercise-induced muscle damage in the repeated bout effect

    Yamaguchi S, Suzuki K, Kanda K, Inami T, Okada J

    Journal of Science and Medicine in Sport   23 ( 6 ) 536 - 540  2020  [Refereed]

    DOI

    Scopus

    8
    Citation
    (Scopus)
  • Is the Optimal Load for Maximal Power Output During Hang Power Cleans Submaximal?

    Seiichiro Takei, Kuniaki Hirayama, Junichi Okada

    INTERNATIONAL JOURNAL OF SPORTS PHYSIOLOGY AND PERFORMANCE   15 ( 1 ) 18 - 24  2020.01

    Authorship:Last author

     View Summary

    Purpose: The optimal load for maximal power output during hang power cleans (HPCs) from a mechanical perspective is the 1-repetition-maximum (1RM) load: however, previous research has reported otherwise. The present study thus aimed to investigate the underlying factors that determine optimal load during HPCs. Methods: Eight competitive Olympic weight lifters performed HPCs at 40%, 60%, 70%, 80%, 90%, 95%, and 100% of their 1RM while the ground-reaction force and bar/body kinematics were simultaneously recorded. The success criterion during HPC was set above parallel squat at the receiving position. Results: Both peak power and relative peak power were maximized at 80% 1RM (3975.7 [439.1] W, 50.4 [6.6] W/kg, respectively). Peak force, force at peak power, and relative values tended to increase with heavier loads (P < .001), while peak system velocity and system velocity at peak power decreased significantly above 80% 1RM (P= .005 and .011, respectively). There were also significant decreases in peak bar velocity (P < .001) and bar displacement (P < .001) toward heavier loads. There was a strong positive correlation between peak bar velocity and bar displacement in 7 of 8 subjects (r> .90, P < .01). The knee joint angle at the receiving position fell below the quarter-squat position above 70% 1RM. Conclusions: Submaximal loads were indeed optimal for maximal power output for HPC when the success criterion was set above the parallel-squat position. However, when the success criterion was defined as the quarter-squat position, the optimal load became the 1RM load.

    DOI

    Scopus

    5
    Citation
    (Scopus)
  • 中学生バスケットボール競技者における大腿四頭筋の構造と跳躍能力および月齢との関係

    関根 悠太, 星川 精豪, 岡田 純一

    発育発達研究   ( 77 ) 10 - 21  2018.03  [Refereed]

    Authorship:Last author

    DOI

  • 遅発性筋肉痛時に更なる伸張性運動を行なうことで次に生じる遅発性筋肉痛は抑制される

    山口翔大, 岡田純一

    NSCAジャパンジャーナル   25 ( 2 ) 18 - 24  2018  [Refereed]

  • Transversus abdominis elasticity during various exercises: A shear wave ultrasound elastography study

    Hirayama K, Akagi R, Moniwa Y, Okada J, Takahashi H

    International Journal of Sports Physical Therapy   12 ( 4 ) 601 - 606  2017  [Refereed]  [International journal]

     View Summary

    BACKGROUND: Although the transversus abdominis (TrA) is considered to play a significant role in maintaining trunk stability, there is little information regarding the type of exercise that best facilitates the development of tension in the TrA. Muscle elasticity shows a strong association with muscle tension. Shear wave ultrasound elastography provides a means by which the tension of TrA can be noninvasively estimated, by quantifying it's elasticity. PURPOSE: The purpose of this study was to examine the TrA elasticity during several exercises as measured by shear wave ultrasound elastography, and to determine which of the studied exercises demonstrated the greatest tension. METHODS: Ten healthy men performed abdominal hollowing, abdominal bracing, a hanging deadlift, elbow-toe plank with contralateral arm and leg lift, and back bridge with single leg lift. During these exercises, TrA elasticity was measured using ultrasound elastography. The same measurements were performed at rest before and after these exercises. RESULT: No significant difference was found for rest conditions measured before and after the exercises (p = 0.63). Abdominal bracing showed a significantly higher elasticity value than the other exercises (p < 0.05), except for hanging deadlift. CONCLUSION: Among the exercises, abdominal bracing was the exercise that elevated the TrA tension the most. The present results also suggested that hanging deadlift also produced comparably high TrA tension with abdominal bracing. LEVEL OF EVIDENCE: 2c.

    PubMed

  • Effects of Resisted Sprint Training on Sprint Performance in High School Baseball Players

    Yuta Sekine, Junichi Okada

    American Journal of Sports Science   4 ( 5 ) 90 - 97  2016.09  [Refereed]

  • Difference in the Recruitment of Hip and Knee Muscles between Back Squat and Plyometric Squat Jump

    Norihide Sugisaki, Sadao Kurokawa, Junichi Okada, Hiroaki Kanehisa

    PLOS ONE   9 ( 6 )  2014.06  [Refereed]

     View Summary

    Athletes who aim to improve both muscular endurance and power often perform exercises that involve similar joint actions under different lifting conditions, such as changes in the load or speed, which are implemented at different times during a periodized exercise program or simultaneously. The prescribed exercises are considered to recruit the same muscles even if the lifting conditions differ to each other. The present study aimed to clarify this by examining whether the recruitment of individual hip and knee muscles during the squat exercise differs between lifting conditions adopted for muscular endurance and power training regimens. Moderately trained men performed back squats (BS), with a load of approximately 60% of one repetition maximum, as a muscular endurance training exercise, and they performed plyometric squat jumping (PSJ) for power training. During each exercise, the lower limb joint torques and the recruitment of five hip and knee muscles were determined with inverse-dynamics and T2-weighted magnetic resonance imaging, respectively. While the maximal and mean knee joint torques were greater during PSJ than during BS (p&lt;0.01), the T2 values for the quadriceps femoris muscle did not differ between the exercises. In contrast, the T2 values of the gluteus maximus and hip adductor muscles were higher during PSJ (p&lt;0.05) than during BS, although there was no significant difference in the mean hip extension torque between the two exercises. The current results indicate that the individual use of the agonist muscles differs between BS and PSJ, and it does not always correspond with the joint kinetics during the exercises. Therefore, in addition to the exercise type, the lifting condition should also be taken into consideration as a determinant of the major muscles trained during a resistance exercise.

    DOI

    Scopus

    15
    Citation
    (Scopus)
  • Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints

    Norihide Sugisaki, Junichi Okada, Hiroaki Kanehisa

    JOURNAL OF SPORTS SCIENCES   31 ( 8 ) 894 - 906  2013.04  [Refereed]

     View Summary

    The present study aimed to quantify the intensity of lower extremity plyometric exercises by determining joint mechanical output. Ten men (age, 27.3 +/- 4.1 years; height, 173.6 +/- 5.4cm; weight, 69.4 +/- 6.0kg; 1-repetition maximum [1RM] load in back squat 118.5 +/- 12.0kg) performed the following seven plyometric exercises: two-foot ankle hop, repeated squat jump, double-leg hop, depth jumps from 30 and 60cm, and single-leg and double-leg tuck jumps. Mechanical output variables (torque, angular impulse, power, and work) at the lower limb joints were determined using inverse-dynamics analysis. For all measured variables, ANOVA revealed significant main effects of exercise type for all joints (P&lt;0.05) along with significant interactions between joint and exercise (P&lt;0.01), indicating that the influence of exercise type on mechanical output varied among joints. Paired comparisons revealed that there were marked differences in mechanical output at the ankle and hip joints; most of the variables at the ankle joint were greatest for two-foot ankle hop and tuck jumps, while most hip joint variables were greatest for repeated squat jump or double-leg hop. The present results indicate the necessity for determining mechanical output for each joint when evaluating the intensity of plyometric exercises.

    DOI

    Scopus

    16
    Citation
    (Scopus)
  • マスターズ・ウエイトリフティング選手の骨密度,筋力,筋断面積から見た高強度レジスタンストレーニングの影響

    岡田純一, 柳谷登志雄, 倉持梨恵子, 鳥居俊

    スポーツ科学研究   10   49 - 61  2013.04

    CiNii

  • ウエイトリフティング選手におけるスナッチおよびスクワットの最高挙上重量と特異動作パワーの関係

    岡田純一

    スポーツ科学研究   10   151 - 163  2013.04

  • Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints.

    Sugisaki Norihide, Okada Junichi, Kanehisa Hiroaki

    Intensity-level assessment of lower body plyometric exercises based on mechanical output of lower limb joints.   31 ( 8 )  2013

     View Summary

    :The present study aimed to quantify the intensity of lower extremity plyometric exercises by determining joint mechanical output. Ten men (age, 27.3 ± 4.1 years; height, 173.6 ± 5.4 cm; weight, 69.4 ± 6.0 kg; 1-repetition maximum [1RM] load in back squat 118.5 ± 12.0 kg) performed the following seven plyometric exercises: two-foot ankle hop, repeated squat jump, double-leg hop, depth jumps from 30 and 60 cm, and single-leg and double-leg tuck jumps. Mechanical output variables (torque, angular impulse, power, and work) at the lower limb joints were determined using inverse-dynamics analysis. For all measured variables, ANOVA revealed significant main effects of exercise type for all joints (P < 0.05) along with significant interactions between joint and exercise (P < 0.01), indicating that the influence of exercise type on mechanical output varied among joints. Paired comparisons revealed that there were marked differences in mechanical output at the ankle and hip joints; most of the variables at the ankle joint were greatest for two-foot ankle hop and tuck jumps, while most hip joint variables were greatest for repeated squat jump or double-leg hop. The present results indicate the necessity for determining mechanical output for each joint when evaluating the intensity of plyometric exercises.

    DOI

    Scopus

    16
    Citation
    (Scopus)
  • 04生-24-ポ-23 スクワットトレーニング動作おける股関節伸展筋群の活動 : Muscle functional MRIを用いた評価(運動生理学,ポスター発表,一般研究発表抄録)

    杉崎 範英, 岡田 純一

    日本体育学会大会予稿集   63 ( 63 ) 148 - 148  2012.08

    DOI CiNii

  • 04生-25-口-10 ウエイトリフティング選手の唾液中の免疫グロブリン(slgA)と健康状況について(04.運動生理学,一般研究発表抄録)

    徳野 裕子, 中達 未佳, 岡部 直子, 平山 邦明, 岡田 純一, 池川 繁樹

    日本体育学会大会予稿集   62 ( 62 ) 122 - 122  2011.09

    DOI CiNii

  • THE RELATIONSHIP BETWEEN MUSCLE THICKNESS IN THE LOWER LIMBS AND COMPETITION PERFORMANCE IN WEIGHTLIFTERS AND SPRINTERS

    Toshihiro Ikebukuro, Keitaro Kubo, Junichi Okada, Hideaki Yata, Naoya Tsunoda

    JAPANESE JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE   60 ( 4 ) 401 - 411  2011.08  [Refereed]

     View Summary

    This study aimed to investigate the differences in the development of muscle thickness (MT) in the lower limbs with specific sports-event training. Furthermore, the relationship between MT of the lower limbs for weightlifters and sprinters and their competition performances (total weight lifted and 100m sprint times) was examined. Subjects were 64 males divided into 3 groups: weightlifters (n=20), sprinters (n=20), and untrained subjects as controls (n=24). The MT {relative to (body weight)(1/3)} of knee extensors (KE), knee flexors (KF), plantar flexors (PF) and dorsi flexors (DF) was measured at 21 sites (proximal, middle and distal) along the length of the upper and lower leg by B-mode ultrasound. The MT of KE for weightlifters was significantly greater than that for sprinters and controls, while the MT of KF and PF for sprinters was significantly greater than that for weightlifters and controls. The MT of rectus femoris (RF), vastus intermedius (VI), vastus lateralis (VL) and vastus medialis (VM) for weightlifters was significantly greater than that for sprinters and controls, while the MT of RF and VM for sprinters was greater than that of controls. On the other hand, the MT of KE for weightlifters and sprinters (especially VM) correlated significantly with competition performances. These results indicated that squatting affected the MT of KE except for RF while sprinting affected the MT of KF and PF. It was also concluded that the MT of KE for weightlifters and sprinters (particularly VM) was related to their competition performances. (Jpn. J. Phys. Fitness Sports Med., 60(4) : 401 similar to 411 (2011))

    DOI

    Scopus

    12
    Citation
    (Scopus)
  • THE RELATIONSHIP BETWEEN MUSCLE THICKNESS IN THE LOWER LIMBS AND COMPETITION PERFORMANCE IN WEIGHTLIFTERS AND SPRINTERS

    Toshihiro Ikebukuro, Keitaro Kubo, Junichi Okada, Hideaki Yata, Naoya Tsunoda

    JAPANESE JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE   60 ( 4 ) 401 - 411  2011.08  [Refereed]

     View Summary

    This study aimed to investigate the differences in the development of muscle thickness (MT) in the lower limbs with specific sports-event training. Furthermore, the relationship between MT of the lower limbs for weightlifters and sprinters and their competition performances (total weight lifted and 100m sprint times) was examined. Subjects were 64 males divided into 3 groups: weightlifters (n=20), sprinters (n=20), and untrained subjects as controls (n=24). The MT {relative to (body weight)(1/3)} of knee extensors (KE), knee flexors (KF), plantar flexors (PF) and dorsi flexors (DF) was measured at 21 sites (proximal, middle and distal) along the length of the upper and lower leg by B-mode ultrasound. The MT of KE for weightlifters was significantly greater than that for sprinters and controls, while the MT of KF and PF for sprinters was significantly greater than that for weightlifters and controls. The MT of rectus femoris (RF), vastus intermedius (VI), vastus lateralis (VL) and vastus medialis (VM) for weightlifters was significantly greater than that for sprinters and controls, while the MT of RF and VM for sprinters was greater than that of controls. On the other hand, the MT of KE for weightlifters and sprinters (especially VM) correlated significantly with competition performances. These results indicated that squatting affected the MT of KE except for RF while sprinting affected the MT of KF and PF. It was also concluded that the MT of KE for weightlifters and sprinters (particularly VM) was related to their competition performances. (Jpn. J. Phys. Fitness Sports Med., 60(4) : 401 similar to 411 (2011))

    DOI

    Scopus

    12
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    (Scopus)
  • ベンチプレス運動中のパワー出力と筋活動パターンに関する研究

    岡田純一, 加藤清忠, 飯島康平, 岡先聖太, 杉崎範英, 赤澤暢彦, 飯田祐士, 長谷川伸

    Strength &amp; Conditioning Journal   17 ( 1 ) 4 - 8  2010.01

    CiNii

  • 04-27-K210-6 重量挙げ選手および陸上短距離選手における下肢筋群の筋厚と競技成績との関係(04.運動生理学,一般研究発表抄録,ひろしま発 ひとを育む体育・スポーツ)

    池袋 敏博, 久保 啓太郎, 八重嶋 克俊, 岡田 純一, 矢田 秀昭, 金久 博昭, 角田 直也

    日本体育学会大会予稿集   60   135 - 135  2009

    DOI CiNii

  • 高齢者にみられる腸腰筋体積の性差

    長谷川伸, 岡田純一, 加藤清忠

    体力科学   57 ( 1 ) 131 - 140  2008.02

     View Summary

    The purpose of this study was to investigate sex differences in the muscle volume (MV) of the iliopsoas, psoas major, and iliacus muscles, normalized by fat free mass (FFM), in the elderly. The subjects were 15 males and 15 females 65 years of age or over. Serial transverse 1.5T magnetic images (10mm slice) of each subject were taken between the 12^<th> thoracic vertebrae and the lesser trochanter. FFM was measured with a bioelectrical impedance analyzer. The mean MV of each muscle on the right and left sides were calculated and used for regression analysis of the relationship between MV and FFM. A significant correlation was observed between MV and FFM of the iliacus in both sexes (p<0.01), but not between the MV and FFM of the psoas major. MV normalized by FFM and cross-sectional area (CSA) normalized by FFM^<2/3> showed significantly greater values for the psoas major in the males than in the females (p<0.001), but there was no sex difference in the MV or CSA normalized by FFM of the iliacus. These results suggest that elderly males tend to have a greater muscle volume and cross-sectional area of the iliopsoas than elderly females, and that these sex differences are attributable to differences in the psoas major.

    DOI CiNii

    Scopus

  • Kinematic Analysis of the Snatch Technique used by Japanese and International Female Weightlifters at the 2006 Junior World Championship

    Junichi Okada, Kohei Iijima, Tetsuo Fukunaga, Toshimi Kikuchi, Kiyotada Kato

    International Journal of Sport and Health Science   6   194 - 202  2008

     View Summary

    The purpose of the present study was to compare the snatch techniques of Japanese and international female weightlifters using kinematic analysis. Motion analysis of the snatch techniques conducted using videos recorded at the 2006 Women's Junior World Weightlifting Championship. The results indicated no significant differences between the snatch techniques of Japanese and international weightlifters in terms of the kinematic parameters expressed by the barbell trajectory and joint angles. However, the interval of time between the peak velocity of the hip joint and peak vertical velocity of the barbell was longer for Japanese weightlifters, while the power applied to the barbell was 35% greater for international weightlifters. These findings indicate that differences in strength and power production affected the performances of Japanese and international weightlifters.

    DOI CiNii

  • Factors Associated with the Stages of Change for Strength Training Behavior

    Kazuhiro Harada, Koichiro Oka, Ai Shibata, Akemi Ota, Junichi Okada, Yoshio Nakamura

    International Journal of Sport and Health Science   6   251 - 263  2008

     View Summary

    The stages of change (Precontemplation, Contemplation, Preparation, Action, and Maintenance) are a key concept of the transtheoretical model. The present study, designed as a cross-sectional study using an Internet questionnaire, was intended to identify characteristics of stages of change for strength training behavior and to examine the relationship between them and self-efficacy for strength training behavior. Measured variables included stages of change for strength training behavior, moderate-vigorous physical activity, type of strength training, self-efficacy for strength training behavior, and socio-demographic variables. Subjects (5,177 Japanese adults; 40.1±12.0 years; recruited from registrants of a social research company) were in the following stages: 39.5% in Precontemplation; 25.1% in Contemplation; 21.0% in Preparation; 5.6% in Action; and 8.8% in Maintenance. The most common types of strength training activities were done at home (74.3%), used the subject's own body weight (60.4%), and were done in the subject's own way (85.1%). ANCOVA results showed a significant association between stages of change and moderate-vigorous physical activity. Subjects who were women, older, unemployed, with lower education levels, or with lower income significantly tended to be classified into the two earlier stages with the χ2 and Kruskal-Wallis tests. In multiple logistic regression analysis, self-efficacy predicted stages of change. Approaches to promote strength training such as enhancement of self-efficacy targeting those who were in earlier stages (e.g. older women) would be needed.

    DOI CiNii

  • 1RMの推定値を用いた授業展開

    岡田純一, 岡先聖太

    ストレングス&amp;コンディショニング   14 ( 9 ) 52 - 55  2007.11

    CiNii

  • 筋力トレーニングのスクワット系とデッドリフト系種目における固有背筋,大殿筋,大腿直筋,大腿二頭筋および内側広筋の筋電図学的研究

    半田徹, 加藤浩人, 長谷川伸, 岡田純一, 加藤清忠

    姿かたち研究   6   33 - 46  2006.09

  • パワークリーンの指導と評価-大学の授業におけるスキルレベル

    岡田純一

    ストレングス&コンディショニング/日本ストレングス&コンディショニング協会   12 ( 7 ) 46 - 49  2005.08

    CiNii

  • EFFECTS OF SQUAT AND POWER CLEAN MOVEMENT POWER ON RUNNING PERFORMANCES IN SPRINTERS

    OKADA J, HARADA T, TSUCHIE H

    NSCA National Conference and Exhibition/ Las Vegas, NV    2005.07

  • EFFECTS OF SQUAT AND POWER CLEAN MOVEMENT POWER ON RUNNING PERFORMANCES IN SPRINTERS

    OKADA J, HARADA T, TSUCHIE H

    NSCA National Conference/ Las Vegas, NV    2005.07

  • 筋力トレーニングのプル系5種目における上腕二頭筋,広背筋および僧帽筋の筋電図学的研究

    半田徹, 加藤浩人, 長谷川伸, 岡田純一, 加藤清忠

    体力科学   54 ( 2 ) 159 - 168  2005.04

     View Summary

    To compare the effectiveness of five different muscle training movements on the biceps brachii, latissimus dorsi and trapezius muscles, eight weight-trained men (age, 20.4±0.5 years) were asked to perform three repetitions, at 70% one repetition maximum, of upright rowing (UR) and bent-over rowing (BR) exercises using a barbell ; and seated rowing (SR), front lat pulldown (LPf) and back lat pull-down (LPb) exercises using a Universal Machine. The activities of the biceps brachii, latissimus dorsi, and trapezius during the elbow flexsion and elbow extension phases of each exercise were analyzed using integrated electromyography (EMG) and normalized I-EMG. The results were as follows : 1. The mean nrmsEMG values for the biceps brachii were larger during UR and LPf exercises than during BR, SR, and LPb exercises, suggesting that UR and LPf are more effective than the other movements for training the biceps brachii. The mean nrmsEMG values for the latissimus dorsi were larger during SR, LPf, and LPb exercises, followed by BR and UR exercises (in descending order), suggesting that SR, LPf, and LPb exercises are more effective than the other movements for training the latissimus dorsi. 2. The mean nrmsEMG values for the upper trapezius were larger during UR and BR exercises than during SR, LPf, and LPb exercises, suggesting that UR and BR exercises are more effective than the other movements for training the upper trapezius. The mean nrmsEMG values for the middle trapezius were larger during BR and SR exercises than during UR, LPf, and LPb exercises, suggesting that BR and SR exercises are more effective than the other movements for training the middle trapezius. The mean nrmsEMG values for the lower trapezius were larger during BR exercise than during other movements, suggesting that BR exercise is more effective than the other movements for training the lower trapezius. 3. In all the exercises, each muscle showed a higher nrmsEMG value during the elbow flexsion phase than during the elbow extension phase. This observation suggests that the training method examined in this study should emphasize the elbow flexsion movement. The present results suggest that UR exercise is the most effective movement for training the biceps brachii and upper trapezius, BR is most effective for training the upper trapezius, middle trapezius and lower trapezius, SR is most effective for training the latissimus dorsi and middle trapezius, LPf is most effective for training the biceps brachii and latissimus dorsi, and LPb is most effective for training the latissimus dorsi.

    DOI CiNii

    Scopus

    10
    Citation
    (Scopus)
  • マスターズリフターの骨密度,筋断面積とパフォーマンス

    岡田純一

    ストレングス&コンディショニング/日本ストレングス&コンディショニング協会   11(9):48-51. ( 9 ) 48 - 51  2004.11

    CiNii

  • FITNESS CHARACTERISTICS OF JAPANESE MASTERS WEIGHTLIFTERS

    Okada J, Yanagiya T, Kuramochi R, Torii S, Kato K

    NSCA National Conference and Exhibition/ Minneapolis, MN    2004.07

  • FITNESS CHARACTERISTICS OF JAPANESE MASTERS WEIGHTLIFTERS

    Okada J, Yanagiya T, Kuramochi R, Torii S, Kato K

    NSCA National Conference and Exhibition/ Minneapolis, MN    2004.07

  • 足関節の反動動作における弾性エネルギーが機械的仕事量および機械的パワーの増強に及ぼす影響.

    杉崎範英, 岡田純一, 金久博昭, 福永哲夫

    人間工学   40 ( 2 ) 82 - 89  2004

     View Summary

    This study aimed to investigate the enhancement of the mechanical work and power in stretch-shortening cycle (SSC) movement of ankle joint, with specific emphasis on the relation with the contribution of elastic energy. Subjects (n=7) jumped on a sledge apparatus using only ankle joint with following three conditions: (1) plantar flexion without counter movement (PFJ), (2) plantar flexion with counter movement (CMJ), and (3) drop jump from a height of 26cm (DJ). In all subjects, mechanical work and power developed at the ankle joint increased in CMJ and DJ. The relative contribution of elastic energy to the total mechanical work during plantar flexion (Wtotlal) was 39.7% in CMJ and 71.7% in DJ. In both conditions, the relative increase in mechanical work and power over PFJ was significantly correlated to the relative contribution of elastic energy. The findings here indicate that 1) the mechanical work by reuse of elastic energy accounts for a large share of Wtotlal in the SSC movement of ankle joint, and 2) the mechanical work and power enhancement in SSC exercise depends on the degree of contribution of elastic energy to Wtotlal.

    DOI CiNii

  • バーの軌跡分析におけるフィードバックと現場のニーズに関する検討

    岡田純一

    サポートシステム開発に関する研究/(社)日本ウエイトリフティング協会    2003.03

  • 報告1 -2002年世界選手権-

    岡田純一

    ウエイトリフティングにおけるスキル評価基準の策定/(社)日本ウエイトリフティング協会    2003.03

  • 大学運動部歴と中高年期における身体活動の関連性に関する研究

    岡田純一, 鳥居俊, 宮内孝知, 柳谷登志雄, 加藤清忠

    体育学研究紀要   35 ( 35 ) 25 - 35  2003.03

    CiNii

  • ストレングストレーニング&コンディショニング第2版

    ブックハウスHD    2002.12

  • 中高齢者における筋力トレーニングの効果と脱トレーニングの影響

    第10回日本運動生理学会大会    2002.07

  • プル系種目の筋力トレーニングにおける上腕二頭筋,広背筋および僧帽筋の筋電図学的分析

    第10回日本運動生理学会大会    2002.07

  • 筋電図学的分析による筋力トレーニングのプレス系5種目における三角筋・上腕三頭筋の活動の違い

    ヒューマンサイエンスリサーチ/人間科学研究科   11  2002.06

  • 継続的な体力測定による大学運動部員の体力水準とその推移

    早稲田大学体育学研究紀要/体育局   34 ( 34 ) 25 - 33  2002.06

    CiNii

  • トレーニング用語辞典【新訂版】

    森永製菓株式会社健康事業部    2001.12

  • ウエイトリフティングの生理学

    スポーツ生理学/市村出版:東京    2001.11

  • Effects of resistance training associated with stretch shortening cycle exercise on force development and muscle volume in human elbow flexsors.

    OKADA J, Fukashiro S

    Advances in Exercise and Sports Physiology/ Japan Society of Exercise and Sports Physiology   7 ( 2 ) 65 - 71  2001.07

  • Effects of resistance training associated with stretch shortening cycle exercise on force development and muscle volume in human elbow flexsors.

    Okada Junichi, Fukashiro Senshi

    Advances in Exercise and Sports Physiology/ Japan Society of Exercise and Sports Physiology   7;2 ( 2 ) 65 - 71  2001.07

     View Summary

    The purpose of this study was to compare the effects of resistance training with counter movement (stretch shortening cycle) or without counter movement (normal style) in elbow flexion. We also attempted to identify the effect of elbow flexors on force development, cross sectional area and volume. Six subjects performed dumbbell curls using their elbow flexor muscles with either theright or left arm for both modes according to random assignment. Training (60% of one repetition maximum × 10 repetitions × 5 sets) was performed 3 days per week for 6 weeks. Maximum force and maximum rate of force development were determined during static and dynamic elbow flexion tests before and after the training period using a special arm ergometer. In addition, muscle volume of elbow flexors (biceps brachii and brachialis muscle) were estimated from magnetic resonance images. Maximum force in the static condition at elbow flexion of 2.09 radians was significantly increased only for stretch-shortening cycle training (from 245±41 to 292±40N, p<0.05). Maximum force and maximum rate of force development during dynamic tests at most loads (2-9kg) were significantly increased (10-15%) for stretch-shortening cycle training. No significant changes were observed in these values for normal style training during the dynamic elbow flexion test. On the other hand, muscle volume was increased only for normal style training (from 269±43 to 30±54cm^3, p<0.05). These results indicated that stretch-shortening cycle training was more effective for dynamic force production than conventional isotonic trauning and that it can be considered a specific mode of training.

    CiNii

  • 早稲田大学体育局体育各部部員の体力測定-第2報-

    体育学研究紀要/体育局   33  2001.03

  • ヒトの歩・走能力の加齢変化

    体育学研究紀要/体育局   33  2001.03

  • 本学学生における英国陸連方式「4種目テスト」を用いた運動能力の評価

    スポーツ健康科学研究/順天堂大学   5 ( 5 )  2001.03

    J-GLOBAL

  • ウエイトトレーニングに関するサポート/<自転車競技>平成11年度バイオメカニクスおよび運動生理学を中心とした医・科学サポート事業報告

    第27回オリンピック競技大会(2000/シドニー)医・科学サポート事業報告/日本オリンピック委員会    2001.03

  • ウエイトトレーニングに関するサポート/<自転車競技>平成12年度オリンピック候補およびオリンピック選手を対象とした総合的医・科学サポート

    第27回オリンピック競技大会(2000/シドニー)医・科学サポート事業報告書/日本オリンピック委員会    2001.03

  • 体脂肪を落とす正しい歩き方

    青春出版社    2000.09

  • Power and force output during a specific movement in weightlifters.

    OKADA J

    NSCA National conference 2000; Journal of Strength and Conditioning Research/National Strength and Conditioning Association   14;3  2000.07

  • Power and force output during a specific movement in weightlifters.

    OKADA J

    NSCA National conference 2000; Journal of Strength and Conditioning Research/National Strength and Conditioning Association   14;3  2000.06

  • 1998年世界選手権におけるスナッチ技術—バーの軌跡から見た失敗の要因

    競技種目別競技力向上に関する研究/日本オリンピック委員会   26  2000.03

  • 早稲田大学体育局体育各部部員の体力測定

    体育学研究紀要/体育局   32  2000.03

  • スナッチ動作中の床反力左右差と競技力

    ウエイトリフティング研究紀要/日本ウエイトリフティング協会   11:15-19  2000.03

  • クイックリフトの実践・指導

    NSCAジャパンジャーナル/NSCAジャパン   6;10 ( 10 ) 24 - 27  1999.12

    CiNii

  • ジュニア期の基礎体力養成・維持のためのトレーニング Vol.4 シーズンごとのプログラム作成

    Club Energen/大塚製薬   1999秋号  1999.10

  • ジュニア期の基礎体力養成・維持のためのトレーニング Vol.3 プログラムデザインの具体例

    Club Energen/大塚製薬   1999夏号  1999.07

  • ジュニア期の基礎体力養成・維持のためのトレーニング Vol.2 期分けトレーニングのそれぞれのポイント

    Club Energen/大塚製薬   1999春号  1999.04

  • 南カリフォルニア大学のスポーツ組織

    体育学研究紀要/体育局   31 ( 31 ) 53 - 59  1999.03

    CiNii

  • 自転車エルゴメータによるペダリング・トレーニングの筋電図学的検討

    競技種目別競技力向上に関する研究/日本オリンピック委員会   22, pp215-221   215 - 221  1999.03

    CiNii

  • 運動三日坊主にはクロストレーニングが効果大

    生活の設計/貯蓄広報中央委員会   200, pp58-61  1999.02

  • ジュニア期の基礎体力養成・維持のためのトレーニング Vol.1 トレーニングに対する考え方

    Club Energen/大塚製薬   1999新春号  1999.01

  • Essentials of strength training and conditioning

    ブックハウスHD    1999.01

  • Lifting technique of weightliters in snatch lift

    OKADA J

    International conference on weightlifting and strength training.    1998.11

  • Lifting technique of weightliters in snatch lift

    OKADA J

    International conference on weightlifting and strength training.    1998.11

  • ウエイトリフティングの床反力左右差

    第51回日本体育学会    1998.10

  • 健康・体力づくりのトレーニング方法-腰痛予防

    はばたき/東京都障害者総合センター   48  1998.03

  • スクワット運動時の補助具の使用が筋活動に及ぼす影響

    体育学研究紀要/体育局   30 ( 30 ) 65 - 71  1998.03

    CiNii

  • 健康・体力づくりのトレーニング方法-筋力2

    はばたき/東京都障害者総合センター   47  1998.01

  • 健康・体力づくりのトレーニング方法-筋力1

    はばたき/東京都障害者総合センター   46  1997.11

  • 中高年齢者の動作パワー発揮能力と定期的運動実践の効果

    日本体育学会第50回大会    1997.10

  • 健康・体力づくりのトレーニング方法-持久性2

    はばたき/東京都障害者総合センター   45  1997.09

  • Functional and morphorogical effects of different resistance training with and without a counter movement in elbow flexors.

    16th Congress of International Society of Biomechanics    1997.08

  • Trunk extension and flexion torque in athletes

    16th Congress of International Society of Biomechanics    1997.08

  • Functional and morphorogical effects of different resistance training with and without a counter movement in elbow flexors.

    16th Congress of International Society of Biomechanics    1997.08

  • Trunk extension and flexion torque in athletes

    16th Congress of International Society of Biomechanics    1997.08

  • 健康・体力づくりのトレーニング方法-脂肪

    はばたき/東京都障害者総合センター   44  1997.07

  • Difference of physical fitness before and after competitive season in high school speed skaters.

    NSCA National Conference    1997.06

  • Difference of physical fitness before and after competitive season in high school speed skaters.

    National Strength and Conditioning Association 20th National Conference    1997.06

  • 健康・体力づくりのトレーニング方法-持久性1

    はばたき/東京都障害者総合センター   43  1997.05

  • 基礎体力トレーニング

    ジュニア期のスポーツライフマニュアル/日本体育協会    1997.04

  • 池畑大(アトランタオリンピック4位)の競技力向上にともなう形態とパワーの変化

    競技種目別競技力向上に関する研究/(財)日本オリンピック委員会   20  1997.03

  • 高校スピードスケート選手に対するスポーツライフマネジメントに関わるサポート活動とその成果

    ジュニア期のスポーツライフに関する研究/(財)日本体育協会   3  1997.03

  • グローブ着用が引き動作の牽引力に及ぼす影響

    競技種目別競技力向上に関する研究/(財)日本オリンピック委員会   20  1997.03

  • 発育期の一流ウエイトリフティング選手の形態および筋機能の縦断的変化

    競技種目別競技力向上に関する研究/(財)日本オリンピック委員会   20  1997.03

  • Kinematic analysis of the barbell during the snatch movement of elite Asian weight lifters

    T Isaka, J Okada, K Funato

    JOURNAL OF APPLIED BIOMECHANICS   12 ( 4 ) 508 - 516  1996.11  [Refereed]

     View Summary

    The purpose of this study was to describe the kinematic characteristics of the snatch technique from the viewpoint of barbell trajectory. Subjects included 6 elite male Asian weight lifters who participated in the first Japan International Friendship Tournament in 1993. Trajectories of the barbell during snatch lifts in the competition were videotaped. Three vertical acceleration peaks of the barbell during the pull movement were observed and corresponded to the first pull, transition, and second pull phases. The angle of the resultant acceleration (ARA) of the barbell averaged 85 degrees in the first pull and transition pull phases. In the second pull phase. the ARA was almost 140 degrees, indicating that the barbell was accelerated anteriorly, away from the lifter. The results of this study suggest that during the first pull and transition pull phases, elite lifters pulled the barbell toward themselves to produce the needed vertical acceleration and that the resulting posterior movement of the barbell was controlled by the forward acceleration produced in the second pull phase.

  • Kinematic analysis of the barbell during the snatch movement of elite Asian weight lifters

    T Isaka, J Okada, K Funato

    JOURNAL OF APPLIED BIOMECHANICS   12 ( 4 ) 508 - 516  1996.11  [Refereed]

     View Summary

    The purpose of this study was to describe the kinematic characteristics of the snatch technique from the viewpoint of barbell trajectory. Subjects included 6 elite male Asian weight lifters who participated in the first Japan International Friendship Tournament in 1993. Trajectories of the barbell during snatch lifts in the competition were videotaped. Three vertical acceleration peaks of the barbell during the pull movement were observed and corresponded to the first pull, transition, and second pull phases. The angle of the resultant acceleration (ARA) of the barbell averaged 85 degrees in the first pull and transition pull phases. In the second pull phase. the ARA was almost 140 degrees, indicating that the barbell was accelerated anteriorly, away from the lifter. The results of this study suggest that during the first pull and transition pull phases, elite lifters pulled the barbell toward themselves to produce the needed vertical acceleration and that the resulting posterior movement of the barbell was controlled by the forward acceleration produced in the second pull phase.

  • 青年男女の下腿形態

    第4回姿かたち研究会/東京    1996.11

  • Effects of different resistance training with and without a counter movement on force production

    1996 NSCA National Conference/Atlanta    1996.06

  • Effects of different resistance training with and without a counter movement on force production

    1996 NSCA National Conference/Atlanta    1996.06

  • 高校スピードスケート選手におけるスポーツライフマネジメントおよび医・科学サポートの試み

    ジュニア期のスポーツライフに関する研究/日本体育協会   2  1996.03

  • ジュニアおよびシニアウエイトリフターの競技成績と除脂肪体重およびパワー発揮能力の比較

    競技種目別競技力向上に関する研究/日本オリンピック委員会   19  1996.03

  • Force-Velocity characteristics of various muscle groups in humans

    **th Congress of the International Society of Biomechanics/University of Jyvaskyla Finland    1995.11

  • Contribution of series elastic component in elbow flexion using stretch-shortening cycle

    **th Congress of the International Society of Biomechanics/University of Jyvaskyla Finland    1995.11

  • 骨量測定に基づく運動・栄養へのアドバイスの試み

    体力科学/日本体力医学会   44;6  1995.09

  • 反動を用いた肘屈曲運動のトレーニング効果

    体力科学/日本体力医学会   44;6  1995.09

  • Force-Velocity characteristics of various muscle groups in humans

    **th Congress of the International Society of Biomechanics/University of Jyvaskyla Finland    1995.07

  • Contribution of series elastic component in elbow flexion using stretch-shortening cycle

    **th Congress of the International Society of Biomechanics/University of Jyvaskyla Finland    1995.07

  • ウエイトリフターのスナッチ動作における挙上技術

    ヒューマンサイエンス・リサーチ/人間科学研究科   4  1995.06

  • Difference in the recruitment of hip and knee muscles between back squat and plyometric squat jump.

    Sugisaki N, Kurokawa S, Okada J, Kanehisa H

    PLoS One   30 ( 9(6) ) e101203  [Refereed]

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Books and Other Publications

  • ストレングス&コンディショニングⅡ【エクササイズ編】

    大修館書店  2003.11

  • ストレングス&コンディショニングⅠ 【理論編】

    大修館書店  2003.04

Works

  • 2006年全日本大学対抗女子ウエイトリフティング選手権大会優勝

    2006.10
    -
     

  • 2005年全日本大学対抗女子ウエイトリフティング選手権大会優勝

    2005.09
    -
     

Presentations

  • そり牽引トレーニングが高校生野球選手の走パフォーマンスに及ぼす影響

    第66回日本体力医学会大会 

    Presentation date: 2011.09

Research Projects

  • 伸張性運動に伴って生ずる筋損傷に対する非侵襲的なバイオマーカーの妥当性

    Project Year :

    2019.04
    -
    2022.03
     

     View Summary

    激しい運動は時に筋損傷(EIMD)を誘発する。多くの先行研究では血中クレアチンキナーゼ(CK)を利用してきた。一方、近年骨格筋を構成する蛋白質であるタイチンのN-末端断片(TNF)が、EIMDに伴い尿中に遊離し、CKと同様の濃度変化を示すことが報告され、尿をEIMDの指標として使用できる可能性が示唆された。本研究は、運動に伴うEIMD評価におけるTNFの妥当性を検討するために、Ⅰ性別、年齢、運動経験が異なる者を対象にTNFの変化、およびⅡEIMDが発症しない持久性運動後のTNFの変化を観察することで特性の異なる被験者への応用や運動様式の違いによるTNFの変動動態を明らかにしていく。激しい運動は時に筋損傷(EIMD)を誘発する。多くの先行研究ではEIMDの発現を評価するために、客観性に優れるバイオマーカーを使用してきた。現在のバイオマーカーは、血中に遊離するクレアチンキナーゼ(CK)の活性変化を評価対象としてきたが、採血には侵襲性を伴うことから被験者の負担が大きい事が問題視されてきた。しかし近年骨格筋を構成する蛋白質であるタイチンのN-末端フラグメントが、EIMDに伴い尿中に遊離し、CKと同様の濃度変化を示すことが報告されたことにより、尿試料をEIMDのバイオマーカーとして使用できる可能性が示唆された。本研究は、運動に伴うEIMD評価における尿中タイチンN末端フラグメント(UTF)の妥当性を検証することを目的とし種々の調査および成果発表を進めた。性差がUTFへ与える影響について、女性群10名、男性群10名を対象に肘関節屈曲筋を対象に、伸張性収縮運動を10回3セット実施した。その結果、全測定項目で群間差が認められなかった。しかし、両群ともに運動課題を最大努力にて実施したにも関わらず、女性群の等尺性最大筋力あたりの仕事量が、男性群と比較して有意に低値を示した。したがって、本研究ではUTFの性差がないものの、今後、運動課題の負荷量を統一して再確認していく必要が考えられた。この他、EIMDが短縮性収縮運動では発症せず、伸張性収縮運動後に特異的に発症することに着目し、持久性運動に関する実験を進めた。この他、UTFが伸張性収縮運動によって発症するEIMDに対して特異的に反応していること、およびUTFが運動誘発性筋損傷の保護効果であるRepeated bout effectを反映する生化学マーカーであることなどを論文発表した。本研究では、UTFのバイオマーカーとしての妥当性を保証する知見を確実なものにするために、Ⅰ:性別、年齢、運動経験が異なる者を対象にUTFの変化を検証すること、およびⅡ:EIMDが発症しないと言われている持久性運動後のUTFの変化について観察することに取り組んでいる。その上でⅠの諸課題を2019および2020年度において実施する計画であったが、妥当性の検証に関する計画とその課題の実施順序を再考した。そのため、Ⅰの性別に関する研究に並行し、Ⅱを開始した。性差がUTFへ与える影響について、女性群10名、男性群10名を対象に肘関節屈曲筋を対象に、伸張性収縮運動を10回3セット実施した。その結果、全測定項目で群間差が認められなかった。しかし、両群ともに運動課題を最大努力にて実施したにも関わらず、女性群の等尺性最大筋力あたりの仕事量が、男性群と比較して有意に低値を示した。したがって、本研究ではUTFの性差がないものの、今後、運動課題の負荷量を統一して再確認していく必要が考えられた。この性差に関する研究についてデータ取得を終え,分析を進め投稿の準備段階となっているが、例数の追加も課題として考えられる。並行して持久性運動に関する研究(Ⅱ)のデータ取得を進め、10例程度の測定を終えたが、コロナ禍となり中断している。事態の収束を見て再開を目指すところである。2020年度前半は2019年度に続きUTFの持つEIMDに対する特異性を検証するために、短縮性自転車運動を用いた「EIMDが発症しない持久性運動後のUTFの変化」を検討する。すなわちCKは長時間の持久性運動で上昇する可能性が高いが、伸張性収縮の生じない自転車運動においてEIMDは発現しない、かつUTFに変化が生じないことを確認し、CKとUTFの発現動態に相違があることを確認することができれば、UTFがEIMDに対して特異的なバイオマーカーと確認できる。引き続き、「運動経験や年齢とUTFの関係」について検討していく。CK活性値は現在の運動状況に左右されやすく、先行研究では日ごろから習慣的に運動を行っている者は行っていない者に比べてCK活性値が上昇しにくいことが報告されている。また、高強度伸張性運動後の筋線維を評価した先行研究では、若年者と比較して高齢者の方がより強く損傷しており、CK活性値も高値を示したことを報告されている。これらの結果を受け、運動習慣のない高齢者、あるいは習慣的に運動を行っている者を対象として高強度伸張性運動課題が尿中UTFに及ぼす影響を検討する。これら一連の実験・測定を2020年度に終え、以後は検体の分析、データ解析を進めていく。2021年度はデータ解析およびそれに基づく成果報告を中心に進める予定である

  • Muscle distribution, power output properties and performance in the weightlifting.

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2012.04
    -
    2015.03
     

    OKADA JUNICHI, KUBO Keitaro, HIRAYAMA Kuniaki, ARAI Kenichi

     View Summary

    The purpose of this study was to clarify a factor about muscle distribution and strength and power output properties which influenced the difference of the performance in the weightlifting. Fifty participants of the high school championships volunteered this study for the muscle thickness and body composition test. Another measurements were executed to get the detail information about muscle distribution, strength and power properties. Nine females and thirteen males top athletes took part in the MRI and several strength/power test. Some of them included Olympian and international level weightlifters. These results showed that elbow extensors, flexors and hamstrings were thicker in males compared with females. Higher muscle strength per unit of muscle cross sectional area in hip extension and knee flexion were observed in top males

  • Analysis of power production and muscle activity in resistance exercise

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2006
    -
    2007
     

    OKADA Junichi, KATO Kiyotada

     View Summary

    Many previous results that objected the muscle activity levels and/or its activity pattern in resistance training provided exercise tempo or velocity during the exercise. There is no report that how to vary the level or output pattern of muscle activity during exercise. It is important to reveal the mechanisms to produce the higher power output during exercise. The purpose of this study was to clarify the variation of the power production and muscle activity pattern during the resistance exercise, according to the power measurement at various loads, the quantified estimation for the muscle activity during exercise.As the most popular resistance exercise, we adopted the elbow curl for the single joint exercise, and the bench press for the multi joint exercise in the power test Two modified exercises that simulated elbow curl and bench press were executed by each experimental group with maximum effort through the range of motion. Healthy male subjects volunteered in this study. Eight subjects participated in the elbow flexion test and ten subjects took part in the bench press test Both tests included that force velocity and power measurement using the special apparatus and isometric test were executed.The results are listed follows:1) There were no significant correlations between the power output and muscle activity levels in both of the single and multi joint movement Present study was adopted the movement with maximum effort for maximized power output Root mean Square values derived from EMG revealed that muscle activity levels during power test with maximum effort did not different, even if produced power is high or low level.2) Peak power appeared at the range from 70 to 80 percent of the total bar displacement in the attempt produced maximum power in the bench press. The role of the muscle activity considered that pectolaris major, deltoid, lateral head of triceps brachii and biceps brachii contributed for stabilizing the shoulder and horizontal flexion of shoulder joint. Activation of long head of triceps brachii showed peak value at the approximately 60 percent of total bar displacement These muscle activity patterns varied depend on the differences force - velocity relationships during the exercise

  • Effects of resistance and EMS training for walking and lower limb functions in elderly

    Project Year :

    2005
     
     
     

  • The Research of EMG activity of the rotator cuff muscles and the optimal training machine production to train those muscles.

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2003
    -
    2004
     

    KATO Kiyotada, OKADA Junichi, HASEGAWA Shin

     View Summary

    【study1】The purpose of this study was to investigate the effect of the difference load and repetition on the EMG activity of shoulder muscles during the performance of the shoulder rotation exercise. EMG activity for the infraspinatus, posterior deltoid, middle deltoid and middle trapezius were recorded using surface electrode and normalized using maximum voluntary contraction.In the relationship between load and %iEMG, the infraspinatus showed significant differences at 20%IS to 60%IS in comparison with that during non-load movement. In the relationship between repetition and %iEMG, the infraspinatus showed significant differences 9 to 20 repetition during 10%IS(isometric strength) movement, 4 to 20 repetition during 20%IS and 1 to 20 repetition during 30%IS in the comparison with that during each non-load monement.These results suggest that 20 repetition and more at 10% IS load, 7 to 10 repetitions at 20%IS load and 3 to 7 repetition at 30%IS load are the appropriate range of training for the infraspinatus muscle.【Study 2】The purpose of this study was to develop the rotator cuff training machine. First, the shoulder rotational strength and range of motion data for males from 12 to 21 years old were collected. From this data, it understood that the load needed for the rotator cuff training machine is light in comparison with the load that is used with an existing training machine. Furthermore, load adjustment for each several hundreds gram is necessary. This research group did the design of the training machine and asked the production of the machine of the manufacturer of the speciality

  • Fitness farm for health promotion

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2000
    -
    2001
     

    MURAOKA Isao, TORII Suguru, NAKAMURA Yoshio, MIYAUCHI Takanori, OKADA Jun-ichi

     View Summary

    The purpose of this study was to investigate 1) the characteristics of the participants in fitness program for health promotion, 2) the effects of fitness program on the physical fitness and lifestyle activity for the participants, and 3) the factors for sustaining healthy lifestyle.
    In the first year, the randomly sampled residents in the area around campus volunteered for questionnaire including lifestyle activity, exercise adherence, health awareness, and QOL. Based on the reference data, we analyze the characteristics of the participants in the fitness program for health promotion. The prior items were, 1) women, 2) over 50 yrs, 3) housewives or non-occupation, 4) the amount of affordable time, 5) awareness for exercise shortage, 6) exercise adherence for health promotion.
    In the second year, the sustaining level of lifestyle activity was investigated especially in the participants of walking program. The two issues for sustaining the enhanced lifestyle activity were 1) the class-walking, 2) the low level of the lifestyle activity before intervention.
    The frame of fitness-farm presented in this study gave the informative infrastructure to develop and evaluate the various programs for health promotion.

  • Development and evaluation of exercise prescription to maintain musculoskeletal function in the aged

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2000
    -
    2001
     

    TORII Suguru, MURAOKA Isao, OKADA Jun-iti, NAKAMURA Yoshio

     View Summary

    (1) Development of the new concept of physical therapy for low-graded knee osteoarthritis(OA) and its evaluation.
    Thirty middle and high aged women with mild symptoms of knee OA were recruited for the subjects of this study. They ware received our intervention program to increase muscle strength about knee and hip joint by those exocises of open kinematic chain. Muscle strength of the most of the subjects increased and their gonalgia reduced.
    Gait analysis revealed that those who widened their stride significantly increased hip strength, especially adductor strength, and that these who have stronger adductor strength show lesser lateral displacement of the knee at stance phase.
    Although, until now, the exercise program for knee OA aimed to increase muscle strength about the knee, our results suggest the effect of the exercise aimed to increse muscle strength of about the hip.
    (2) Development of the new concept of physical therapy for prevention of osteoporosis (OP) and its evaluation.
    36 female subjects older than 40 years were recruited for this study. They were instructed of the special exercise to load lower extremities and trunk once a week. In addition, they made exercise schedule in their daily life. Bone mineral density of lumbar spine (DEXA) were maintained and bone stiffness score of calcaneus (QUS) increased. But, EMD of the subjects of menopausal phase decreased. Although bone specific AlP increased and urine deoxypyridinoline decreased from baseline to mid, the fomer decreased and the latter increased from mid to postintervention. These phenomenon suggest that the load of the exercise after adaptation and protocol for subjects of menopausal phase should be improved.

  • Effects of regularly performed resistance training on body composition, plasma lipid profiles, and bone health status in middle-aged women

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    1999
    -
    2000
     

    KIKURA Yasuko, HIGUCHI Mitsuru, KASAI Junichi, OKADA Junichi

     View Summary

    The purpose of this study is to determine the physical, physiological, and biochemical effects of resistance training in middle-aged women. The results of resistance training was compared with another different training modes, such as jogging/running, swimming, and tennis. Furthermore, middle-aged and young non-exercise women took part in the controls. Each subject completed their food records and caloric and major nutrient intakes were estimated.
    Serum high-density lipoprotein cholesterol (HDL-C) levels was significantly higher in female endurance runners than in equal groups of female resistive trainers and sedentary female controls. Resistive trainers and controls showed no significant differences in HDL-C. No significant dose-response relationships were found for either runners or resistive trainers when daily training duration, weekly training frequency, and weekly mileage were correlated with HDL-C. It was concluded that HDL-C levels in females are associated with specific training methods.
    The results of this study indicate that mean bone formation values were significantly less in the swimming group than in the resistive trained and jogging/running groups. The results also determined that mean bone resorption values were significantly less in the resistive trained and jogging/running groups than in the swimming and non-exercise control groups. The uncoupling index was significantly greater in the swimming group than in the jogging/running and control groups. That the low levels of impact associated with non-weight-bearing activities, such as swimming, appear to negatively influence bone formation. These findings support the theory that high strain rates are more effective at inducing new bone formation.
    From the results of this study, it was concluded that resistance training is effective exercise mode to maintain and improve physical, physiological, and biochemical health status in middle-aged women.

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Misc

 

Syllabus

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Overseas Activities

  • Tactical Athleteに対するStrength and Conditioning Program の構築・実践方法に関する研究

    2021.03
    -
    2022.03

    米国   ルイジアナ州立大学シュリーブポート校

Sub-affiliation

  • Affiliated organization   Global Education Center

  • Faculty of Sport Sciences   Graduate School of Sport Sciences

Internal Special Research Projects

  • 伸張性運動に伴って生ずる筋損傷に対する非侵襲的なバイオマーカーの妥当性

    2018   鈴木克彦

     View Summary

    本研究は,タイチンNフラグメント(TF)が持つバイオマーカーとしての妥当性を検討するために,運動誘発性筋損傷中の尿中TF濃度と血中Creatine Kinase(CK)活性値および筋損傷諸指標との相関関係と,各被験者の尿中TF濃度応答の相違を決定する要因を明らかにすることを目的とした.健常男性16名に対し,肘関節屈曲筋群の最大伸張性収縮運動実施前,運動直後,24〜144時間後に諸測定を実施するとともに,質問紙によりトレーニング履歴を得た.その結果,TFはCKおよびその他筋損傷指標と強い相関関係を持ち,各被験者の尿中TF濃度の相違にはトレーニング履歴が要因として関与していることが示唆された.

  • ウエイトリフティングにおける競技力と筋の分布および出力特性

    2011  

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    【緒言】ウエイトリフティング競技においては、スナッチおよびクリーン&ジャークの2種目による挙上重量の合計(トータル)によって順位が決定される。ウエイトリフティング選手を対象とした研究において、挙上動作のバイオメカニクス的研究、選手の形態および身体組成(体脂肪率、除脂肪体重、筋断面積)、あるいは筋力、パワー出力に関する検討など様々な側面から検討がなされている。 除脂肪体重は競技成績に関わる身体的因子として確認されており(加藤ら1990、岡田ら1995)、下肢の筋断面積あるいは筋量を評価した研究においても同様の結果が報告されている(金久ら1989)。 しかし、競技は階級制(男子8階級、女子7階級)であり、一部の階級(男子56kg級および105kg超級、女子48kg級および75kg超級)を除き、各階級では女子5-6kg、男子6-11kgの範囲の体重の者が出場していることになる。したがって、同一階級内では、ほぼ同様な除脂肪体重あるいは筋量であるもの同士が争っていることになるが、当然ながら競技成績においては選手間に差が生まれている。 例えば、ジュニア世界選手権に出場する選手においては、技術的に他国と目立った遜色は無いにも関わらず、バーの挙上時に発揮されているパワーは同大会優勝者が35%高値を記録している(Okada et al。 2008)。すなわち、一般的傾向として競技力(挙上重量)は除脂肪体重あるいは筋断面積と相関しているけれども、それらだけでは実際の競技力を反映できていない。同程度の除脂肪体重(筋量)のものが争い、その中で挙上重量に差が生じている背景として、神経系の働きや筋断面積あたりの筋力、などがその因子として推察されるが、ウエイトリフティング選手を対象として、この点に焦点を当てた研究は報告されておらず、推測の域を出ていない。本研究はウエイトリフティング選手の競技力の差違に影響する筋量やその分布に関する因子を明らかにすることを目的とした。【方法】対象者はウエイトリフティング競技者89名であった。その内訳は男子61名、女子28名である。さらに日本ウエイトリフティング協会医科学委員会の協力を得て、測定の機会をナショナル合宿、高校エリート合宿、および全国高校選抜大会とした。その結果、対象者の属性を女子3群(ナショナル、高校選抜、大学生)、男子4群(ナショナル高校、エリート、高校選抜、大学生)とした。しかし、全ての群に共通した測定は筋厚だけであり、身体組成は高校選抜群だけとなった。インピーダンス法による身体組成計測器(Inbody720)によって、高校選抜群についてだけ体重、体脂肪率、除脂肪体重を求めた。筋厚の分布を評価するため、安部らの方法に基づき、右側の上腕前部、上腕後部、腹部、下背部、肩甲骨下部、大腿前部、大腿後部、下腿前部、下腿後部に探触子を当て超音波画像を撮像した。得られた画像から皮下脂肪と骨および腹腔までの距離を計測し、装置が規定したスケールを使用し実長換算しmmで表した。【結果】男子においては、下腿後部を除いて競技レベルの高い群の方が筋厚が厚い傾向にあった。また高校選抜群が低値で高校エリート群はナショナル群に匹敵する筋厚値であった。同じく女子においては全ての筋厚値においてナショナル群が高値を示していた。除脂肪体重と競技記録の関係については高校選抜群男女と先行研究のナショナルチーム(岡田ら1995)と中学生男子と比較した。その結果、4群ともに除脂肪体重と挙上記録の間に有意な正の相関関係を認め、且つその回帰式の傾きに差は無かったが、切片が異なっていた。すなわち同じ除脂肪体重であっても、その挙上記録のレベルが異なっていることが観察された。ナショナル群が最も高く、次に高校選抜男子群、さらにその下に高校選抜女子群と中学生男子が同様に位置していた。【考察】筋厚分布から、競技レベルの高い群に優位であったのは、上腕後部と大腿後部が注目される。また、男子高校エリート群は高校選抜群よりもナショナル群により近い傾向にあり、高校時代に卓越した身体(ナショナルに匹敵する筋厚)を獲得した選手が、のちにその筋量あたりの出力を高めて記録を向上させていく様相が推察される。また、この傾向は除脂肪体重を筋量の指標と考えると、競技レベルの向上にともなって、筋量あたりの挙上記録の向上が主因であることが推察された。【結論】 ウエイトリフティング選手の挙上記録に影響の強い部位として、上腕後部および大腿後部である可能性が示唆された。また、除脂肪体重が挙上記録と相関の高い因子であるけれども、除脂肪体重あたりの挙上記録を高めることが競技レベルの向上のために求められることが推察された。

  • 青年期の運動履歴が中高年期におけるスポーツ活動歴と体力プロフィールに及ぼす影響

    2002   加藤 清忠, 矢島 忠明, 小野沢 弘史, 宮城 淳, 柳谷 登志雄, 鳥居 俊, 宮内 孝知

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    大学運動部出身者の中高年期における運動・スポーツ習慣の実態を明らかにすることを目的とし,過去の運動経験および現在の運動習慣に関する質問紙調査を実施した.9つの競技種目(野球、漕艇、陸上、テニス、柔道、水泳、アメリカンフットボール、ウエイトリフティング)の本学体育各部出身者2,145名に対して調査用紙を配布し,777名から回答を得た.その結果,以下のようなことが明らかとなった.1)98.4%が日常生活の中で運動やスポーツは大切だと考えていた.2)在学時の週間頻度は全体で5.56±1.57日/週,一日の平均練習時間は3.23±1.44時間/日であった.高値を示したのは頻度において水泳(6.14日/週),時間においては庭球(4.62時間/日)であった.3)大学卒業後も定期的な運動を継続したものは59.6%であった.そのうちゴルフの割合が34.4%を占めていた.しかし,4日/週以上の高い週間頻度を有するものの中でもっとも実施されていたのはウォーキング(34.8%)であった.4)健康・体力増進を目的としてスポーツを行うものが多数であるが,勝つために行うという意識が一般よりも高かった.また,現状をさらに改善したいという意欲が高かった.5)大学卒業後も運動を継続している群では31.9%が人並み以上の体力があると感じていた.非継続群においても一般より体力が低いと感じているのはごく少数(6.5%)であった.以上の結果から,大学運動部出身者は学生時のスポーツ経験を背景に,その後も積極的に運動・スポーツを継続ようとする意識を持ち健康・体力レベルを維持していることが示唆された.

  • 中高年者の長期的筋力トレーニングに関する研究

    2000  

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     加齢にともなう身体諸機能、筋力およびその機能の低下は傷(障)害を引き起こす要因として考えられている。そのため筋力トレーニングは高齢者においても身体機能を改善するための手段として、活用され始めている。しかし、ウエイトリフティングのような高強度の筋力トレーニングを長期間実施している者の実態は明らかではない。つまり高強度のトレーニングを中高年になっても継続している彼らの身体的特徴を明らかにすることで中高年者におけるトレーニングの有効性やトレーニングのあり方を検討する資料になるものと考えられる。そこで本研究の目的は筋力トレーニングを長期にわたって継続している中高年者に対して、過去・現在の運動習慣や生活習慣に関する調査および身体的機能に関する測定を実施し、生理学的な指標に基づいて筋力トレーニングの影響について検討することであった。ウエイトリフティング競技を実施しているT群9名(52.6±6.8歳)と同年代の一般成人C群6名(52.0±7.1歳)を対象とし健康、生活習慣、運動習慣に関する質問紙調査、有酸素性持久力、膝関節、股関節の伸展・屈曲筋力、重心動揺、特異動作パワー(スナッチ、スクワット)、骨密度(踵骨、腰椎)、筋断面積の評価を実施した。 腰椎の骨密度においてT群1.435±0.288、C群1.049±0.191と有意に高い値を示したが、踵骨では差が認められなかった。T群がバーベルを挙上するという外的負荷に長期間曝され、腰椎への刺激が大きかったことが反映しているものと推察された。一方、筋力において先行研究で報告されている若年アスリートに匹敵する値を示すものもいたが、平均値ではC群と顕著な差を見出すことはできなかったが。とくに単関節で測定した膝および股関節筋力では、T群の全員が当該部位に変形やヘルニアといった整形外科的所見を有していたことが影響したものと考えられる。長期的な筋力トレーニングの実践は筋力および骨密度への効果が期待されるが、過度なものは障害の誘因となり得る。よって、健康づくりといった観点では至適な処方をさらに検討する必要性が示唆された。

  • 模擬動作パワーによる最高挙上重量の推定に関する研究-模擬スクワット運動時のパワー測定の条件に関する研究

    1998  

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     筋力トレーニングは競技者だけではなく,一般成人においてもそのQuality of Lifeを高める手段として,広範に取り入れられている.筋力トレーニングの処方において,実施者の能力を適切に評価し,至適な強度のトレーニング処方を設定することは,トレーニングの効果をより引き出すことに繋がり,トレーニング中の事故あるいは傷害を防ぐことにもなる.しかし,至適な強度を導くためには,最大挙上重量(1RM)を能力の評価基準として,実測あるいは推定し,それに対する相対値を使うことが要求される.この1RMの評価は実際に自己の限界の重量に挑戦することをともなっているが,挙上重量と反復回数の関係から推定する方法も提案されている.しかし,技術が未熟な段階でも最大挙上重量を安全に精確に評価し得る方法を開発することが必要と考えられた.そこで本研究はスクワット運動を対象として,その動作条件,等張性負荷装置を用いたパワー測定時の諸変量および1RMの関係を検討し,簡易なパワー測定から精度の高い1RMの推定を試みるものであった. パワー測定装置に特注のアタッチメントを介して実際にトレーニングで使用するバーを取り付けた.この装置でスクワットの模擬運動を最大努力で行い,その時の時間-速度,張力およびパワー曲線からそのピーク値を記録した.また,負荷を変えた数試行中の最大値を抽出した.さらに,この動作の短縮性収縮局面を開始する膝関節角度の差異や負荷条件についても種々検討した.その結果,膝関節角度は大腿部が床と平行である深い位置(パラレル),あるいは浅い位置(120度)よりも,90度の条件が最も高いパワーを発揮できる傾向にあった.一方,力,速度およびパワーの最大値と1RMの関係は,力との相関が高い傾向を示していた.今後も検討を重ね,より精度の高い推定法の開発を進めていく.

  • 筋量およびその分布と筋力・パワー発揮能力に関する研究

    1997  

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    身体運動において、その運動で発揮される力を定量すること、そしてその発揮された力に貢献している要因を明らかにすることは、スポーツトレーニングおよび健康・体力づくりにおける運動プログラムを構築していく上で重要である。身体外部に発揮されている出力を担っている諸筋群の活動様相をとらえること、筋量を評価していくことで、適切に運動プログラムを作成していくための諸指標を明確にしていくことになろう。本研究は日常生活でも頻繁におこなわれている動作様式、且つトレーニング種目としても重要な動作を対象としてその力発揮に関わる身体の条件を検討していくことがねらいであった。そこで、スクワット動作(しゃがんで立ちあがる動作)中の筋活動様相を明かにすることを手始めにおこなった。この動作は初心者に対して行う際には、適切な姿勢を指導することが重要であり、補助具を使用することが実施上の安全性を高める上で一助となることが予想された。そこで、補助具の使用の有無がスクワット動作中の筋活動に及ぼす影響について実験をおこなった。男子学生10名を被験者とし、補助具の有無とスクワット運動時の膝関節伸展筋群(大腿直筋)および股関節伸展筋群(脊柱起立筋、大腿二頭筋、および大殿筋)の筋放電量(積分筋電図)および股関節の最大屈曲角度に関する検討をおこなった。その結果、股関節の屈曲角度は補助具使用時に3.5%減少していた(p<0.01).スクワット動作全体での積分筋電図では差が見られなかったが、動作を下降運動局面(Eccentrc; 求心性収縮局面)と上昇運動局面(Concentric; 求心性収縮局面)とに分割した場合、遠心性収縮局面の大殿筋および求心性収縮局面の大腿直筋において積分筋電図は有意に増大していた(p<0.05)。以上の結果から、補助具の使用によって動作中の体幹の前傾姿勢が抑制され、膝伸展筋群により大きな筋収縮を促す可能性が示唆された。この結果から筋量と出力の関係を検討していく上で対象とすべき筋の特定をすること、動作の規定を決定する上で重要な成果が得られた。今後も、筋量評価のためのプロトコルづくりを重ね、動作中の出力の定量化と合わせて検討を進めていく。研究成果の発表:早稲田大学体育学研究紀要 Vol. 30, 1998.

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