Updated on 2022/07/02

写真a

 
TAKARADA, Yudai
 
Affiliation
Faculty of Sport Sciences, School of Sport and Sciences
Job title
Professor

Concurrent Post

  • Faculty of Sport Sciences   Graduate School of Sport Sciences

  • Affiliated organization   Global Education Center

Education

  •  
    -
    1997

    The University of Tokyo   Graduate School of Education  

  •  
    -
    1989

    Waseda University   Faculty of Education   Department of Education  

Degree

  • The University of Tokyo   Master's degree in Pedagogy

  • The University of Tokyo   Doctor's degree in Mutidisciplinary Scineces

Research Experience

  • 2005
    -
     

    ~2008年 早稲田大学イノベーションデザイン研究所研究員

  • 2003
    -
     

    ~2005年 早稲田大学スポーツメセナ研究所研究員

  • 2000
    -
    2003

    Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo   Research assistant

  • 1997
    -
    2000

    Yokohama Sports Medical Center   Researcher for health science

Professional Memberships

  •  
     
     

    Japan Society of Exercise and Sports Physiology

  •  
     
     

    Japanese Society of Physical Fitness and Sports Medicine

  •  
     
     

    Physiological Society of Japan

  •  
     
     

    Human Brain Mapping

  •  
     
     

    Japan Neuroscience Society

 

Research Areas

  • Sports sciences

Research Interests

  • human brain, unconscious motor control, maximal volitional force/ occlusion, muscle function & CSA, vascular endothelial function

Papers

  • Shouting strengthens maximal voluntary force and is associated with augmented pupillary dilation

    Takarada, Y, Nozaki, D

    Scientific Reports   11 ( 18419 ) 1 - 11  2021.09  [Refereed]

    Authorship:Lead author, Corresponding author

  • The unconscious mental inhibiting process of human maximal voluntary contraction

    Yudai Takarada, Daichi Nozaki

    Psychological Research    2021.08  [Refereed]

    Authorship:Lead author, Corresponding author

    DOI

  • What is subliminal goal-priming with motivational reward?

    Yudai Takarada

    Clinical Neuroscience   38 ( 6 ) 756 - 759  2020.04  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

  • Motivational goal-priming with or without awareness produces faster and stronger force exertion

    Takarada, Y, Nozaki, D

    Scientific Reports   8 ( 10135 ) 1 - 12  2018.07  [Refereed]

    Authorship:Lead author, Last author

     View Summary

    Previous research has demonstrated that barely visible (subliminal) goal-priming with motivational<br />
    reward can alter the state of the motor system and enhance motor output. Research shows that these<br />
    afective-motivational efects result from associations between goal representations and positive<br />
    afect without conscious awareness. Here, we tested whether motivational priming can increase motor<br />
    output even if the priming is fully visible (supraliminal), and whether the priming efect occurs through<br />
    increased cortical excitability. Groups of participants were primed with either barely visible or fully<br />
    visible words related to efort and control sequences of random letters that were each followed by fully<br />
    visible positively reinforcing words. The priming efect was measured behaviourally by handgrip force<br />
    and reaction time to the grip cue after the priming was complete. Physiologically, the efects were<br />
    measured by pupil dilation and motor-evoked potentials (MEPs) in response to transcranial magnetic<br />
    stimulation during the priming task. Analysis showed that for both the supraliminal and subliminal<br />
    conditions, reaction time decreased and total force, MEP magnitude, and pupil dilatio

    DOI

  • The impact of aerobic exercise training with vascular occlusion in patients with chronic heart failure

    Tanaka Y, Takarada Y

    ESC Heart Failure   5   586 - 591  2018.05  [Refereed]

    DOI

  • Pupil dilations induced by barely conscious reward goal-priming

    Yudai Takarada, Daichi Nozaki

    NEUROPSYCHOLOGIA   103   69 - 76  2017.08  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    The topic of unconscious influences on behavior has long been explored as a way of understanding human performance and the neurobiological correlates of intention, motivation and action. Previous research using transcranial magnetic stimulation has demonstrated that barely visible priming of an action concept, when combined with reward in the form of a consciously perceived positive stimulus, can alter the state of the motor system and enhance the maximal voluntary force level. One possible explanation is that positive stimulus-induced reward signals are processed by the dopaminergic system in the basal ganglia, motivating individuals to increase the effort they invest in particular behaviors, or to recruit the resources necessary for maintaining those behaviors. If so, given that the dopaminergic system has functionally and anatomically close connections with the noradrenergic system, we hypothesize that the state of the noradrenergic system may be enhanced by the same process. In accord with this hypothesis, we observed that barely visible goal priming with reward caused pupil dilation, suggesting that activity in the noradrenergic system increased. Importantly, this enhancement was accompanied by an unconscious increase in handgrip force. This is the first objective evidence that the pupil-linked neuromodulatory system is related to implicit learning of the link between physical exertion and reward, probably in the noradrenergic system, resulting in more forceful voluntary motor action in the absence of conscious awareness.

    DOI

  • “Sense of effort” and M1 activity with special reference to resistance exercise with vascular occlusion

    Takarada, Y

    J Phys Fitness Sports Med   5 ( 2 ) 123 - 130  2016  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

     View Summary

    Low-to-moderate intensity resistance exercise with vascular occlusion induces increased<br />
    muscle mass and strength, comparable to that after conventional heavy resistance training.<br />
    Also, participants feel as if they require greater force (effort) to lift a weight when undergoing<br />
    resistance exercise following vascular occlusion. Vascular occlusion of the proximal upper<br />
    arm increased perceived magnitude of exerted hand-grip force without causing any accompanying<br />
    changes either in electromyographic or efferent/afferent activity of the median nerve. There<br />
    was also no effect on motor evoked potentials in the hand following resting-state transcranial<br />
    magnetic stimulation (TMS) over the primary motor cortex (M1). Moreover, low-frequency,<br />
    repetitive transcranial magnetic stimulation (lf-rTMS) over the left primary somatosensory cortex<br />
    did not significantly affect estimations of right-hand grip force exertion. Thus, the primary<br />
    factor responsible for the overestimation of force exertion with increased voluntary effort (“sense<br />
    of effort”) during occlusion was the central signal related to motor command size. Brain imaging<br />
    studies show that vascular occlusion increases M1 activi

    DOI

  • Inhibition of the primary motor cortex can alter one's "sense of effort": Effects of low-frequency rTMS

    Yudai Takarada, Tatsuya Mima, Mitsunari Abe, Masahiro Nakatsuka, Masato Taira

    NEUROSCIENCE RESEARCH   89   54 - 60  2014.12  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    Studies using force-matching tasks have suggested that when we feel a "sense of effort," cortical regions may act to increase motor commands, and thus recruit additional motor units, in order to compensate for the exerted force. We hypothesized that suppressing activity in the primary motor cortex (M1), which is the source of the motor commands, would initiate the same process, and induce the same sense of effort. In a force-matching task, grip force was applied to 'right' hand and 10 healthy participants were asked to try to exert the same amount by using 'left' hand, with no visual feedback. On some trials, low-frequency, repetitive transcranial magnetic stimulation (1f-rTMS) was used to suppress the M1 and the primary somatosensory cortex (SI) in the left hemisphere, separately. Results showed that participants tended to overestimate the level of exerted force by up to 24%. In contrast, sham stimulation of the M1 and If-rTMS over the SI did not significantly affect participants' estimations. Further, the M1 suppression resulted in a 42% reduction in motor-evoked potentials. Thus, the M1 suppression can affect our sense of effort, suggesting that compensatory neural mechanisms that increase the MI activity may play an important role in producing senses of effort. (C) 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

    DOI

  • Maximal Voluntary Force Strengthened by the Enhancement of Motor System State through Barely Visible Priming Words with Reward

    Yudai Takarada, Daichi Nozaki

    PLOS ONE   9 ( 10 ) e109422  2014.10  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    The topic of unconscious influences on behaviour has long been explored as a means of understanding human performance and the neurobiological correlates of intention, motivation, and action. However, what is relatively unknown is whether subconsciously delivered priming stimuli, with or without rewards, can affect individuals' maximum level of force produced with their best effort. We demonstrated using transcranial magnetic stimulation that barely visible priming of an action concept, when combined with a reward in the form of a consciously visible positive stimulus, could alter the state of the motor system. In accordance with this neurophysiological alteration, the prime-plus-reward stimuli significantly increased the hand-grip force level of maximum voluntary contraction with little conscious awareness. This is the first objective evidence that the barely conscious presence of a behavioral goal can influence the state of the motor system and arouse latent ability for human force exertion.

    DOI

  • Hypnotic suggestion alters the state of the motor cortex

    Yudai Takarada, Daichi Nozaki

    NEUROSCIENCE RESEARCH   85   28 - 32  2014.08  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    Hypnosis often leads people to obey a suggestion of movement and to lose perceived voluntariness. This inexplicable phenomenon suggests that the state of the motor system may be altered by hypnosis; however, objective evidence for this is still lacking. Thus, we used transcranial magnetic stimulation of the primary motor cortex (M1) to investigate how hypnosis, and a concurrent suggestion that increased motivation for a force exertion task, influenced the state of the motor system. As a result, corticospinal excitability was enhanced, producing increased force exertion, only when the task-motivating suggestion was provided during hypnotic induction, showing that the hypnotic suggestion actually altered the state of M1 and the resultant behavior. (C) 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

    DOI

  • オスグッドシュラッタ—病における手術前後の疼痛の経時的変化

    望月麻紀, 宝田雄大, 友添秀則, 大坂昴

    The Japanese Journal of Rehabilitation Medicine   51 ( 4 ) 283 - 287  2014  [Refereed]

    DOI

  • Effect of transient vascular occlusion Of the upper arm on motor evoked potentials during force exertion

    Yudai Takarada, Yukari Ohki, Masato Taira

    NEUROSCIENCE RESEARCH   76 ( 4 ) 224 - 229  2013.08  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    We previously observed that transient vascular occlusion in volunteers increased the estimation of force exertion with no change in peripheral nerves or muscles. We hypothesized that the primary factor responsible for the overestimation of force exertion during occlusion was the centrally generated motor command, as hypothesized by McCloskey et al. (1974) and McCloskey (1978, 1981). In the present study, we tested the hypothesis that transient vascular occlusion increases the excitability of the primary motor cortex (M1) during force exertion. Healthy human volunteers lay on a bed and squeezed a dynamometer in their right hand. Repetitive gripping forces were exerted at 20%, 40%, or 60% of maximum force, with or without transient (20s) vascular occlusion of the proximal portion of the right upper arm. During the task, single-pulse transcranial magnetic stimulation was applied to the contralateral M1 to induce motor evoked potentials (MEPs) in the flexor carpi ulnaris (FCU) muscle. The MEP amplitudes were enhanced with occlusion under all conditions, with the exception of 60% contraction. In contrast, no significant difference was observed between the MEP amplitudes obtained from the occluded or non-occluded, relaxed FCU muscle. These results suggest that transient vascular occlusion increases the excitability of M1 only during force exertion. (C) 2013 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

    DOI

  • 膝靱帯損傷に対する血流制限下リハビリテーション

    三瓶良祐, 小林龍生, 宝田雄大, 三尾健介, 田中公一朗, 小倉正恒

    メディカルリハビリテーション   154 ( 154 ) 59 - 63  2013  [Refereed]

  • 膝前十字靭帯再建術後の大腿四頭筋萎縮および筋力-血流制限下トレーニングの効果-

    三瓶良祐, 小林龍生, 宝田雄大

    運動・物理療法   23 ( 4 ) 431 - 435  2012  [Refereed]

    Authorship:Last author

  • Endocrine and hyperemic responses to low-intensity aerobic exercise with vascular occlusion

    Takarada Y, Itou M

    Sport Science Research   9   350 - 365  2012  [Refereed]

    Authorship:Lead author, Corresponding author

  • The scientific basis and the future possibility for ischemic resistance training

    Takarada, Y

    Clinical Neuroscience(臨床神経科学)   28 ( 11 ) 1216 - 1217  2010  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

  • 早稲田大学ラグビー蹴球部におけるスポーツ医・科学サポート

    宝田雄大

    スポーツ科学研究   5   212 - 223  2008  [Refereed]

    Authorship:Lead author, Corresponding author

  • Force overestimation during tourniquet-induced transient occlusion of the brachial artery and possible underlying neural mechanisms

    Y Takarada, D Nozaki, M Taira

    NEUROSCIENCE RESEARCH   54 ( 1 ) 38 - 42  2006.01  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    Avascular occlusion by a tourniquet inflated at the proximal end of the upper arm is Suggested to affect the estimation of exertion force level. In the first part of this study, subjects were asked to estimate the isometric force exerted by the occluded hand with that of the other hand (matching experiment). We found that the perceived force with arterial occlusion was always overestimated. To examine the underlying neural mechanism for this phenomenon, in the second part, the somatosensory evoked potentials (SEPs) and nerve action potential (NAP) were recorded following electrical median nerve stimulation with or without arterial occlusion. Moreover, the maximum motor response (M response) to median nerve stimuli at the axilla was recorded from the skin surface of the thenar eminence muscle of the hand during with arterial occlusion. The N20 of SEP and NAP at Erb's point were unaffected by the arterial occlusion, and the M response was also unchanged. These results suggest that the tourniquet-induced transient occlusion of the brachial artery does not seriously affect median nerve function. Thus, it is likely that the primary responsible factor for the overestimation of perceived force exertion during arterial occlusion is the centrally generated motor command as previously hypothesized by McCloskey [McCloskey, D.I., Ebeling, P., Goodwin, G.M.. 1974. Estimation of weights and tensions and apparent involvement of a "sense of effort". Exp Neurol. 42, 220-232; McCloskey, D.I., 1978. Kinesthetic sensibility. Physiol, Rev. 58, 763-820; McCloskey. D.I., 1981. Corollary discharge and motor commands and perception. In: Brookhart, J.M., Mountcastle. V.B. (Eds.), Handhook of Physiology. American Physiological Society, Bethesda, pp. 1415-1447]. (c) 2005 Elsevier Ireland Ltd and the Japan Neuroscience Society. All fights reserved.

    DOI

  • Cooperative effects of exercise and occlusive stimuli on muscular function in low-intensity resistance exercise with moderate vascular occlusion

    Y Takarada, T Tsuruta, N Ishii

    JAPANESE JOURNAL OF PHYSIOLOGY   54 ( 6 ) 585 - 592  2004.12  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    To obtain insight into the relative contributions of exercise and occlusive stimuli to these muscular adaptations, the present study investigated the short- and long-term effects of varied combinations of low-intensity exercise and vascular occlusion. The subjects were separated into 3 groups (n = 6 for each group): low-intensity with vascular occlusion (LIO), low-intensity without vascular occlusion (LI), and vascular occlusion without exercise (VO). LIO and LI groups performed bilateral knee extension exercises in seated positions with an isotonic extension machine. In the LIO group, both sides of the thigh were pressure-occluded at the proximal end by means of a tourniquet during the entire session of exercise (similar to 10 min), whereas only the occlusion with the same pressure and duration was given in the VO group. The mean occlusion pressure was 218 +/- 8.1 mmHg (mean +/- SE). The exercise session consisted of five sets of exercise at an intensity of 10-20% 1 RM and was performed twice a week for 8 wk. After the period of exercise training, isometric and isokinetic strengths at all velocities examined increased significantly in the LIO group (p &lt; 0.05), whereas no significant change in strength was seen in the LI and VO groups. The increase in muscular strength in LIO was associated with a significant increase in the cross-sectional area of knee extensor muscles by 10.3 +/- 1.6%. The plasma growth hormone concentration measured 15 min after the session of exercise showed a marked increase only in LIO. The results showed that the low-intensity exercise and occlusive stimuli have cooperative effects in the long-term adaptation of muscle and an acute response to growth hormone.

    DOI

  • Evaluation of muscle damage after a rugby match with special reference to tackle plays

    Y Takarada

    BRITISH JOURNAL OF SPORTS MEDICINE   37 ( 5 ) 416 - 419  2003.10  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    Objective: To investigate blood indices of muscle damage after a competitive rugby match.
    Methods: Fifteen elite amateur rugby players volunteered to participate (mean (SE) age 26.6 (0.7) years, height 179.8 (1.0) cm, weight 87.4 (2.2) kg, and VO(2)MAX 58.5 (1.2) ml/kg/min). The study was conducted after two competitive matches during the 1999-2000 season. Plasma concentrations of lactate, potassium (K+), sodium (Na+), and myoglobin, and the activity of creatine kinase were measured before and after the matches. In addition, the number of tackles by and on each subject and the average duration of the work and rest periods were analysed using video recordings of the matches.
    Results: Myoglobin concentration and creatine kinase activity showed appreciable transient increases after the match. Peak values for myoglobin concentration (980 (166) mu g/l) and creatine kinase activity (1081 ( 159) U/l) were observed 45 minutes and 24 hours after the match respectively. Positive and significant correlations were observed between the number of tackles and both peak myoglobin concentration (r = 0.85, p&lt; 0.01; n = 14) and peak creatine kinase activity (r = 0.92, p&lt; 0.01; n = 14). Plasma lactate and K+ concentrations also showed appreciable increases after the match, whereas plasma Na+ concentration showed a gradual decrease. The mean duration of the work and rest periods were 21.5 (2.2) and 24.3 (3.1) seconds respectively.
    Conclusions: The rugby matches resulted in serious structural damage to the muscles, the extent of which was highly dependent on the number of tackles.

    DOI

  • Effect of low-load resistance exercise with moderate restriction of blood flow on muscle strength of the lower extremities for top athletes (Paper)

    Takazawa, S, A. Kurosawa, H. Ikeda, H. Oota, Y. Takarada

    Orthop. Surg. Traumatol.   46   1273 - 1279  2003  [Refereed]

    Authorship:Last author

  • Effects of resistance exercise combined with vascular occlusion on muscle function in athletes

    Y Takarada, Y Sato, N Ishii

    EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY   86 ( 4 ) 308 - 314  2002.02  [Refereed]

    Authorship:Lead author

     View Summary

    The effects of resistance exercise combined with vascular occlusion on muscle function were investigated in highly trained athletes. Elite rugby players (n = 17) took part in an 8 week study of exercise training of the knee extensor muscles. in which low-intensity [about 50% of one repetition maximum] exercise combined with an occlusion pressure of about 200 mmHg (LIO. n=6). low-intensity exercise without the occlusion (LI. n = 6), and no exercise training (untrained control. it = 5) were included. The exercise in the LI group was of the same intensity and amount as in the LIO group. The LIO group showed a significantly larger increase in isokinetic knee extension torque than that in the other two groups (P &lt; 0.05) at all the velocities studied. On the other hand. no significant difference was seen between LI and the control group. In the LIO group, the cross-sectional area of knee extensors increased significantly (P&lt;0.01). suggesting that the increase in knee extension strength was mainly caused by muscle hypertrophy. The dynamic endurance of knee extensors estimated from the decreases in mechanical work production and peak force after 50 repeated concentric contractions was also improved after LIO. whereas no significant change was observed in the LI and control groups. The results indicated that low-intensity resistance exercise causes, in almost fully trained athletes. increases in muscle size. strength and endurance, when combined with vascular occlusion.

    DOI

  • Effects of low-intensity resistance exercise with short interset rest period on muscular function in middle-aged women

    Y Takarada, N Ishii

    JOURNAL OF STRENGTH AND CONDITIONING RESEARCH   16 ( 1 ) 123 - 128  2002.02  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    We investigated the effect of low-intensity resistance exercise training on muscular size and strength where the interset rest period was shortened so as to reduce the metabolite clearance. Female subjects (aged 45.4 +/- 9.5 years, n = 10) performed bilateral knee extension exercises in a seated position on an isotonic leg extension machine. The exercise sessions consisted of 3 sets of exercise at a mean intensity of similar to50% 1RM with an interset rest period of 30 seconds and was performed twice a week for a period of 12 weeks. The strength and the cross-sectional area (CSA) of the knee extensors and flexors were examined with an isokinetic dynamometer and magnetic resonance imaging (MRI), respectively. The CSAs of the knee extensors and flexors increased by 7.1 +/- 1.6% (p &lt; 0.01, Wilcoxon signed rank test) and 2.5 +/- 1.4% (not significant), respectively. Isometric and isokinetic strengths increased significantly (p &lt; 0.01) at all velocities examined, whereas no significant change was observed in those of knee flexors. These results indicate that a low-intensity resistance exercise with a short interset rest period is substantially effective in inducing muscular hypertrophy and concomitant increase in strength.

    DOI

  • アスレティックリハビリテーションにおける血流制限下でのトレーニングの応用(解説)

    宝田雄大

    トレーニング科学(特集 スポーツ選手に対するリハビリテーショントレーニングへの科学的アプローチ)   ( 14 号 ) 67 - 74  2002  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

  • 加圧式筋力トレーニングのメカニズム(解説)

    宝田雄大

    体育の科学(特集 新しい視点からみた筋の働き)   ( 52 ) 626 - 634  2002  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

  • Applications of vascular occlusion diminish disuse atrophy of knee extensor muscles

    Y Takarada, H Takazawa, N Ishii

    MEDICINE AND SCIENCE IN SPORTS AND EXERCISE   32 ( 12 ) 2035 - 2039  2000.12  [Refereed]

    Authorship:Lead author

     View Summary

    Purpose: We have previously shown that the combination of low-intensity resistive exercise and moderate vascular occlusion induces in humans a marked increase in growth hormone secretion and muscular hypertrophy. The present study investigated the effects of vascular occlusion on the size of thigh muscles in patients who underwent an operation for the reconstruction of the anterior cruciate ligament to see whether it attenuates the disuse muscular atrophy without any exercise combined. Methods: Two sessions of occlusive stimulus, each consisting of five repetitions of vascular occlusion (mean maximal pressure, 238 mm Hg) for 5 min and the release of occlusion for 3 min, were applied daily to the proximal end of the thigh from 3rd to 14th days after the operation. Changes in the cross-sectional area (CSA) of thigh muscles were analyzed with magnetic resonance images taken on the 3rd and 14th day after the operation. Results: Without occlusive stimulus (control), the CSAs of knee extensors and flexors decreased by 20.7 +/- 2.2% and 11.3 +/- 2.6% (mean +/- SEM, N = 8), whereas with the occlusive stimulus, they decreased by 9.4 +/- 1.6% and 9.2 +/- 2.6% (N = 8), respectively. The relative decrease in CSA of knee extensors was significantly (P &lt; 0.05) larger in the control group than in the experimental group. Conclusion: The results indicate that the occlusive stimulus effectively diminishes the postoperation disuse atrophy of knee extensors.

  • Effects of resistance exercise combined with moderate vascular occlusion on muscular function in humans

    Y Takarada, H Takazawa, Y Sato, S Takebayashi, Y Tanaka, N Ishii

    JOURNAL OF APPLIED PHYSIOLOGY   88 ( 6 ) 2097 - 2106  2000.06  [Refereed]

    Authorship:Lead author

     View Summary

    Acute and long-term effects of resistance exercise combined with vascular occlusion on muscular function were investigated. Changes in integrated electromyogram with respect to time (iEMG), vascular resistive index, and plasma lactate concentration were measured in five men either during or after elbow flexion exercises with the proximal end of the arm occluded at 0-100 mmHg. The mean iEMG, postexercise hyperemia, and plasma lactate concentration were all elevated with the increase in occlusion pressure at a low-intensity exercise, whereas they were unchanged with the increase in occlusion pressure at high-intensity exercise. To investigate the long-term effects of low-intensity exercise with occlusion, older women (n = 24) were subjected to a 16-wk exercise training for elbow flexor muscles, in which low-intensity [similar to 50-30% one repetition maximum (1 RM)] exercise with occlusion at similar to 110 mmHg (LIO), low-intensity exercise without occlusion (LI), and high- to medium-intensity (similar to 80-50% 1 RM) exercise without occlusion (HI) were performed. Percent increases in both cross-sectional area and isokinetic strength of elbow flexor muscles after LIO were larger than those after LI (P &lt; 0.05) and similar to those after HI. The results suggest that resistance exercise at an intensity even lower than 50% 1 RM is effective in inducing muscular hypertrophy and concomitant increase in strength when combined with vascular occlusion.

  • Rapid increase in plasma growth hormone after low-intensity resistance exercise with vascular occlusion

    Y Takarada, Y Nakamura, S Aruga, T Onda, S Miyazaki, N Ishii

    JOURNAL OF APPLIED PHYSIOLOGY   88 ( 1 ) 61 - 65  2000.01  [Refereed]

    Authorship:Lead author

     View Summary

    Hormonal and inflammatory responses to low-intensity resistance exercise with vascular occlusion were studied. Subjects (n = 6) performed bilateral leg extension exercise in the seated position, with the proximal end of their thigh compressed at 214 +/- 7.7 (SE) mmHg throughout the session of exercise by means of a pressure tourniquet. Mean intensity and quantity of the exercise were 20% of 1 repetition maximum and 14 repetitions x 5 sets, respectively. In each set, the subjects repeated the movement until exhaustion. Plasma concentrations of growth hormone (GH), norepinephrine (NE), lacate (La), lipid peroxide (LP), interleukin-6 (IL-6), and activity of creatine phosphokinase (CPK) were measured before and after the exercise was finished and the tourniquet was released. Concentrations of GH, NE, and La consistently showed marked, transient increases after the exercise with occlusion, whereas they did not change a great deal after the exercise without occlusion (control) done at the same intensity and quantity. Notably, concentration of GH reached a level -290 times as high as that of the resting level 15 min after the exercise. IL-6 concentration showed a much more gradual increase and was maintained at a slightly higher level than in the control even 24 h after exercise. Concentrations of LP and CPK showed no significant change. The results suggest that extremely light resistance exercise combined with occlusion greatly stimulates the secretion of GH through regional accumulation of metabolites without considerable tissue damage.

  • ラグビー競技に必要な筋力(解説)

    宝田雄大

    Sportsmedicine Quarterly   ( 22 号 ) 38 - 40  1998.03  [Refereed]  [Invited]

    Authorship:Lead author

  • 血流制限下でのレジスタンス・トレーニング-新しいトレーニング方法-(解説)

    宝田雄大

    体育の科学(特集 レジスタンス・トレーニング)   48   36 - 42  1998.01  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

  • Stretch-induced enhancement of mechanical work production in frog single fibers and human muscle

    Y Takarada, H Iwamoto, H Sugi, Y Hirano, N Ishii

    JOURNAL OF APPLIED PHYSIOLOGY   83 ( 5 ) 1741 - 1748  1997.11  [Refereed]

    Authorship:Lead author

     View Summary

    The relations between the velocity of prestretch and the mechanical energy liberated during the subsequent isovelocity release were studied in contractions of frog single fibers and human muscles. During isometric contractions of frog single fibers, a ramp stretch of varied velocity (amplitude, 0.02 fiber length; velocity, 0.08-1.0 fiber length/s) followed by a release (amplitude, 0.02 fiber length; velocity, 1.0 fiber length/s) was given, and the amount of work liberated during the release was measured. For human muscles, elbow flexions were performed with a prestretch of varied velocity (range, 40 degrees; velocity, 30-180 degrees/s) followed by an isokinetic shortening (velocity, 90 degrees/s). In both frog single fibers and human muscles, the work production increased with both the velocity of stretch and the peak of force attained before the release up to a certain level; thereafter it declined with the further increases of these variables. In human muscles, the enhancement of work production was not associated with a significant increase in integrated electromyogram. This suggests that changes in intrinsic mechanical properties of muscle fibers play an important role in the stretch-induced enhancement of work production.

  • Stretch-induced enhancement of mechanical power output in human multijoint exercise with countermovement

    Y Takarada, Y Hirano, Y Ishige, N Ishii

    JOURNAL OF APPLIED PHYSIOLOGY   83 ( 5 ) 1749 - 1755  1997.11  [Refereed]

    Authorship:Lead author

     View Summary

    The relation between the eccentric force developed during a countermovement and the mechanical power output was studied in squatting exercises under nominally isotonic load (50% of 1-repetition maximum). The subjects (n = 5) performed squatting exercises with a countermovement at varied deceleration rates before lifting the load. The ground reaction force and video images were recorded to obtain the power output of the body. Net muscle moments acting at hip, knee, and ankle joints were calculated from video recordings by using inverse dynamics. When an intense deceleration was taken at the end of downward movement, large eccentric force was developed, and the mechanical power subsequently produced during the lifting movement was consistently larger than that produced without the countermovement. Both maximal and mean power outputs during concentric actions increased initially with the eccentric force, whereas they began to decline when the eccentric force exceeded similar to 1.4 times the sum of load and body weight. Video-image analysis showed that this characteristic relation was predominantly determined by the torque around the knee joint. Electromyographic analyses showed no consistent increase in time-averaged integrated electromyograph from vastus lateralis with the power output, suggesting that the enhancement of power output is primarily caused by the prestretch-induced improvement of an intrinsic force-generating capability of the agonist muscle.

  • 中高年における筋力トレーニング(総説)

    宝田雄大

    トレーニング科学   7 ( 2 ) 67 - 76  1995.10  [Refereed]  [Invited]

    Authorship:Lead author, Corresponding author

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Books and Other Publications

  • 筋肉研究最前線

    宝田 雄大( Part: Contributor, 加圧トレーニング法の開発)

    エヌ・ティー・エス  2019.08

  • 『教養としてのスポーツ科学(改訂版)』(分担執筆)第1部1章(4)「パフォーマンスと脳活動」

    宝田雄大

    大修館書店  2011.04

  • 『Examination of Power Training in Older Adults』 by Josh Butts (翻訳)

    宝田雄大

    日本フィットネス協会  2009.02

  • 『Training for Independence』 by Thomas P. Mahady (翻訳)

    宝田雄大

    日本フィットネス協会  2008.05

  • 『Shoulder Stability Exercise Training』 by Pter Ronei (翻訳)

    宝田雄大

    日本フィットネス協会  2003.06

  • 『薬いらずのボディ・メイク』(単著)

    宝田雄大

    ベースボール・マガジン社  2002.11

  • 『ラガーマンの肉体改造法』(単著)

    宝田雄大

    ベースボール・マガジン社  2002.06

  • 『薬いらずの肉体改造法』(単著)

    宝田雄大

    ベースボール・マガジン社  2001.09

  • 第2章ラグビー選手の持久力、『競技スポーツにおけるエンデュランストレーニングの実際と課題』トレーニング科学研究会編著、pp90-97.(分担執筆)

    宝田雄大

    朝倉書店  1994

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Works

  • Japan Rugby Football Union Conditioning & Science staff

  • Japan Rugby Football Union Medical&Science staff

  • Sports Medicine & Science Support in the Waseda University Rugby Football

Research Projects

  • 最大随意筋収縮の運動システムの活動を抑制する無意識の心象

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    Project Year :

    2021.04
    -
    2024.03
     

    宝田 雄大

  • 最大を表す語彙を伴った無自覚的動機づけが運動系と瞳孔調節系神経活動に与える影響

    日本学術振興会  科学研究費助成事業 基盤研究(C)

    Project Year :

    2018.04
    -
    2021.03
     

    宝田 雄大

     View Summary

    本研究の第二の目的は、最大を表す語彙を伴った無覚的動機づけが運動系、瞳孔関連神経調節系、運動出力に与える影響を明らかにするために、古典的条件付けを模したパラダイム下(Takarada & Nozaki, 2014; 2017)でTMSの反対側M1単発刺激のMEP、瞳孔径等を取得し、握力に与える影響を調べることである。
    次年度は最大を表す語彙を伴った無覚的動機づけの視覚刺激を作成するために、①「最大の」と前向き形容詞の努力感[category-ratio (CR-10) scale]と好感度(a 9-point scale)の定量化とそれらの比較、②運動目標となる身体活動を表す動詞と中性の副詞の選定と好感度の定量化、③それらの視覚刺激の対呈示のサブリミナルテストをおこなった。その結果、①「最大の」、「非常な」、「かなりの」の努力感と好感度はそれぞれ9.7±0.64とM=7.1±1.45、8.2±1.29 とM=5.5±1.48、7.8±1.33とM=5.9±1.54であり、「最大の」が最も大きな努力感と好感度を表す形容詞であることがわかり、②動詞では「発揮する」、「成し遂げる」、「果たす」、「実行する」、「行う」が、副詞では「ほとんど」、「少なくとも」、「最終的に」、「ほぼ」、「すでに」が選定され、それらの好感度はそれぞれM=6.93と(M=5.38)であった。また、運動目標となる動詞の閾下呈示のサブリミナルテストの結果は49.9%±1.6%であり、それらの見えが意識的に上らないことがわかった。
    以上から、最大を表す語彙を伴った無覚的動機づけでは、「最大の」と「発揮する」、「成し遂げる」、「果たす」、「実行する」、「行う」とを対呈示し、閾下と閾上呈示時間はそれぞれ、33msと150msとなった。

  • The effects of physical exercise on various brain function and their application for the health science.

  • Activity of primary motor cortex closely correlated with sensation of effort

  • 無自覚的動機付けの皮質脊髄路興奮性と運動行動に与える持続的効果

    科学研究費助成事業(早稲田大学)  科学研究費助成事業(基盤研究(C))

  • The effects of low-intensity resistance exercise combined with vascular occlusion on the central nervous activity : fMRI study

  • The project of health promotion in Kagamigahara city

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Presentations

  • Is it enough for neuronal excitability of MI to produce force perception? Yudai Takarada, Tatsuya Mima, Masahiro Nakatsuka, Mitsunari Abe, Hidenao Fukuyama, and Masato Taira (Poster)

    The 30th Annual Meeting of Japan Neuroscience Society 

    Presentation date: 2007.09

  • 虚血が引き起こす筋肥大と力の知覚の増大 宝田雄大(口頭)

    バイオを論じる会 (防衛医科大学校) 

    Presentation date: 2007.01

  • Activity of primary motor cortex closely correlated with force perception. Yudai Takarada (Oral)

    Presentation date: 2007.01

  • Activity of primary motor cortex closely correlated with sensation of force. Yudai Takarada, Tomoki Haji, and Masato Taira (Poster)

    The 12th Annual Meeting of the Organization for Human Brain Mapping 

    Presentation date: 2006.06

  • 重さの知覚 宝田雄大(口頭)

    随意運動の調節機構とその病態生理研究会 

    Presentation date: 2006.03

  • 力の知覚に一致した一次運動野の活動性 一fMRIによる研究 宝田雄大(口頭)

    「スポーツと脳機能」 早稲田大学人間総合研究センター 

    Presentation date: 2006.03

  • Activity of primary motor cortex closely correlated with sensation of force. Yudai Takarada, Haji,and Masato Taira (Poster)

    The 28th Annual Meeting of the Japan Neuroscience Society 

    Presentation date: 2005.07

  • Somatosensory evoked potentials during tourniquet-induced transient occlusion of the brachial artery. Masato Taira and Yudai Takarada (Poster)

    The 82rd Annual Meeting of the Physiological Society of Japan, Sendai. Jpn. J. Physiol 

    Presentation date: 2005.05

  • 張力の知覚に一致した一次運動野の活動性 宝田雄大、泰羅雅登(口頭)

    日本大学医学部 学術フロンティア研究会 「皮質運動野を考える : 機能とその関連領域」 

    Presentation date: 2005.02

  • Resistance Exercise Combined with Vascular Occlusion. Yudai Takarada (Symposium)

    The 7th IOC Olympic World Congress on Sport Science 

    Presentation date: 2003.10

  • 血流制限下筋力トレーニングが中枢神経系の活動量に与える影響 宝田雄大(ポスター)

    第58回日本体力医学会大会 

    Presentation date: 2003.09

  • ラグビーが引き起こす筋損傷の評価−タックル数との関係から−宝田雄大(口頭)

    第54回日本体育学会 

    Presentation date: 2003.09

  • 血流制限下における運動時の神経筋活動および呼吸循環の変化 吉武康栄,篠原稔,立正伸,宝田雄大,神崎素樹,宮崎正己,福永哲夫 (ポスター)

    第15回呼吸研究会 

    Presentation date: 2000.09

  • 局所加圧による血流制限を組み合わせた持久的トレーニングの生理学的効果 吉武康栄,篠原稔,立正伸,神崎素樹,宝田雄大,宮崎正己,福永哲夫(ポスター)

    第55回日本体力医学会大会 

    Presentation date: 2000.09

  • 血流制限下のレジスタンストレーニングが運動後のホルモン動態及び炎症性サイトカインに及ぼす影響 宝田雄大,有賀誠司,恩田哲也,中村豊,宮崎誠司,石井直方 (ポスター)

    第53回日本体力医学会大会 

    Presentation date: 1998.09

  • 血流制限下での筋力トレーニングが一流選手の筋力,筋持久力及びパワーに及ぼす効果 宝田雄大,佐藤義昭,石井直方 (口頭)

    第48回日本体育学会 

    Presentation date: 1997.10

  • 血流制限下での筋力トレーニングがもたらす一流選手の骨格筋肥大と筋力増大 宝田雄大,高沢晴夫,石井直方 (口頭)

    第52回日本体力医学会大会 

    Presentation date: 1997.09

  • 適度な血流制限下での筋力トレーニングがもたらす骨格筋肥大と筋力の増大 宝田雄大,高沢晴夫,佐藤義昭,石井直方(口頭)

    第47回日本体育学会 

    Presentation date: 1996.09

  • 局所的な血流制限下でのレジスタンストレーニング−2.中高年者の骨格筋に及ぼす長期的効果− 石井直方,宝田雄大,田中泰博,佐藤義昭,高沢晴夫 (ポスター)

    第51回日本体力医学会大会 

    Presentation date: 1996.09

  • 局所的な血流制限下でのレジスタンストレーニング−1.運動時の筋活動レベル及び抹消血流動態−宝田雄大,高沢晴夫,佐藤義昭,石井直方 (ポスター)

    第51回日本体力医学会大会 

    Presentation date: 1996.09

  • Slack test法を応用したヒト骨格筋の収縮要素と直列弾性要素の力学解析 石井直方,宝田雄大 (ポスター)

    第47回日本体育学会 

    Presentation date: 1996.09

  • ラグビー競技の特性及び運動形態を反映させた持久的トレーニングがシャトルラン中の酸素摂取量に及ぼす影響宝田雄大,平野裕一,福永哲夫(ポスター)

    第8回トレーニング科学研究会 

    Presentation date: 1996.03

  • スクワット動作における予備伸張と発揮パワーとの関係 宝田雄大,平野裕一,石毛勇介,石井直方(ポスター)

    第8回トレーニング科学研究会 

    Presentation date: 1996.03

  • 骨格筋の予備伸張によるパワーの増強−複関節運動の場合−宝田雄大,平野裕一,石毛勇介,石井直方(ポスター)

    第46回日本体育学会 

    Presentation date: 1995.10

  • Prestretch-Induced enhancement of mechanical work in contractionos of frog and human muscles:Effects of prestretch velocity.Takarada,Y.,Iwamoto,H.,Sugi,H.,Hirrano,Y.,and Ishii,N (Poster)

    Com. Phyciol. Biochem. 

  • Effects of prestretch on the mechanical energy liberation in contractions of frog and human muscles. Takarada,Y.,Iwamoto,H.,Sugi,H.,Hirrano,Y.,and Ishii,N (Poster)

    Asian Sports Science Congress, Hiroshima'94 

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Specific Research

  • 反対側重量合わせ法における力の知覚創出関連領野の解明~fNIRSによる研究~

    2009  

     View Summary

     主観的な力の大きさの判断(力覚)は求心性経路の神経入力というよりはむしろ、その筋力発揮に注がれる遠心性経路の神経入力により密接に依存し形成されることが知られている(McCloskey, 1978)。 一方、虚血は力の知覚を顕著に増大させる(Takarada et al., 2006)。すでに短時間の上腕基部への局所的な圧迫は、正常な末梢神経機能を阻害しないことが分かっているので、この知覚の増大は発揮筋力に注がれる中枢性の要因に起因する可能性が高い。また、反対側重量合わせ法で左半球体性感覚野へのrTMSは力覚に何らの変化も与えず、逆に左MIへの磁気刺激による機能低下は、力覚を変化、増加させた(Takarada et al., submitted)。これらの結果は、改めて、McCloskey (1978)の考えを実証するものであった。しかし、rTMS刺激によるMI機能低下は①MI自身の、あるいは&#10113;MIへ出力細胞をもつ領野の神経活動高進のいずれかで補償されなければならない。 さて本研究の目的は、力覚の評価法の一つ、反対側重量合わせ法実施中の脳機能画像をfNIRSにより取得し、力覚関連領野を明らかにすることである。予備実験でわかったことは以下の点である。①fNIRS がfMRIに比べ空間分解能が悪く、fMRIのように脳機能部位の詳細な解剖学的位置づけが困難である②脳深部はもとより、小脳の機能が評価できない③赤外線照射から受光までの光路長が不明なので、得られたデータは相対的な変化であり、したがって、各チャンネルの直接比較や非連続的な経時データの直接比較が困難である④fNIRSでの計測されたヘモグロビン変化と脳神経活動の関連性の解明が不十分である以上のことから、今後の力覚関連領野の解明には、fMRIによる脳機能画像取得を中心に、実験計画を再考する予定である。

  • 局所的な血流制限下の筋運動が血管機能に与える影響

    2008  

     View Summary

    本研究遂行には血管機能評価が必要不可欠である。検査装置には、デジタル式カラー超音波診断装置、血管内皮機能検査自動化システム、プレシスモグラフ、プレシスモグラフ(アセチルコリン)、薬物負荷などがある。特定課題A(一般助成)(H21~H21)で、検査装置の選定を、被験者への負担、コスト、装置自体の再現性や妥当性などの観点から慎重に進めた結果、デジタル式カラー超音波診断装置を用いることに決定した。 さて本研究の血管内皮機能は、上腕動脈の血流依存性血管拡張反応(flow-mediated dilatation; FMD)を超音波診断装置(帯域中端数5~12Hz)により得られた画像の血管径の変化より定量化し評価された。しかし、実際の検査では、改めて、検査対象となる上腕動脈の画像取得箇所の決定及び、当該箇所への超音波診断装置のエコープローブによる(接触)圧の低減とその保持が、測定値の妥当性、正確性、および再現性に必要不可欠であることが判明した。さらに、プローブの保持は検査の阻血-再環流後の血管移動を考慮に入れ微調整をする必要があり、測定者の検査に対する慣れと高い技術が必要であった。これまでに(20年度)、上述の問題点に対応するために、被験者の上腕部の固定と、エコープローブの固定とその位置調整のためのアジャスター付FMD検査台を作製し、より正確で再現性の高い、血管内皮機能検査法が確立できたと考えている。

  • 血流制限下の筋力トレーニングが中枢神経系の活動量に与える影響

    2003  

     View Summary

    目的局所的な血流制限下で筋力トレーニングを行うと、その運動強度が通常、筋肥大を期待することができない低強度であるにもかかわらず、顕著な筋力と筋断面積の増加を引き起こす。運動強度が低い場合、局所的な血流制限は活動筋内の酸素不足と代謝産物の筋外排出の抑制を引き起こす。こうした筋内環境の変化は、運動中の筋活動レベルや成長ホルモン分泌量を増加させる。これらは交感神経活動に深く関係していると考えられるので、本研究の目的は血流制限下筋力トレーニングが中枢神経系の活動量に与える影響を調べることとする。方法被検者は、右利きの健常男子1名(身長173cm、体重76kg、年齢38歳)とした。測定装置は、機能的(f)MRI (1.5-T Siemens Vision scanner)と高磁場内で使用可能な(非磁性体金属製)握力及び筋電図記録装置から成る。血流制限下の掌握運動中(等尺性筋力発揮)の脳活動の時間的変化をfMRIにより記録し、中枢神経系の活動量が調べられた(TR= 4s; FOV= 192 mm X 192 mm; マトリックス= 64 mm X 64mm; スライス数= 10 ; スライス厚= 3mm)。脳機能画像はStatistical Parametric Mapping (SPM)99 を用いて解剖学的標準脳に照らし合わせ解析し、脳賦活領域を確認した。なお、脳画像賦活領域の検出には、T検定が用いられた。被検者は、視覚的フィードバックシステム(リアルフィードバック用波形表示プログラムソフト、パーソナルコンピューター、カラーLCDプロジェクター、及びMRI頭部コイル内に設置された可変式レンズから成る)により発揮筋力レベルを正確に知ることができた。結果と議論局所的な血流制限は、低強度な運動中の大脳皮質の賦活レベルを有意に高める可能性が示唆された。このことは、上記生理反応の発現機序解明の有力な知見となろう。また、局所的な筋運動が中枢系の活性を介して身体の恒常性に寄与することが示されれば、健康体力作りにおける運動の位置づけが確立される。一方本実験により、EMG測定などによるノイズ軽減対策の検討やブロックデザインなどの実験条件の精査が今後の課題として明確化された。

 

Syllabus

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Social Activities

  • 早稲田大学ラグビー蹴球部におけるスポーツ医・科学サポート

    2004.06
    -
    2009.05

  • (財)日本ラグビーフットボール協会 強化委員会 強化委員

    2003.04
    -
    2005.03

  • (財)日本ラグビーフットボール協会 医・科学委員会 科学・情報担当委員

    2003.04
    -
    2005.03

Media Coverage

  • Entered the 1995 Touch World Cup in Hawai as a representative for Japan

    Other

    Federation of International Touch (https://www.internationaltouch.org/)  

    1995.03