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间歇性低氧训练、疲劳和恢复对H反射参数影响初探 总被引：2，自引：0，他引：2
目的:研究间歇性低氧训练(IHT),以及训练结束后的运动性疲劳与恢复过程对H反射各参数的影响.方法:用自制低氧混合气体,对8名短跑运动员进行每日10～11%O2的循环低氧刺激,持续两周,在IHT前后以及IHT之后的疲劳与恢复过程进行H反射各参数测试.结果:两周IHT训练前后M波振幅增加,H波潜伏期升高,差异具有显著性;疲劳后即刻H渡振幅下降,恢复期前三分钟H波振幅显著降低,随后逐渐恢复,在恢复期第15分钟,H波振幅显著升高.结论:H反射是敏感的反映低氧训练以及疲劳对短跑运动员神经系统的影响指标,并提示H反射低氧训练的改变以及运动性疲劳前后以及恢复期的变化与两周低氧训练引起的H反射通路脊髓水平的适应性有关. 相似文献
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《European Journal of Sport Science》2013,13(4):318-326
AbstractThe purpose of this study was to examine whether split step (small hop before step) would be more beneficial than no-split condition in simulated tennis response situation. In addition, it was studied if movement time of the response is related to separately measured force production capabilities and reflex sensitivity of the players. Nine skilled male tennis players participated in this study. Subjects stood on a force plate and reacted to a light signal and moved to appointed direction as fast as possible. With split step the participants were 13.1% faster (P <0.05) than without split step from the start to the distal end of the so called close range movement continuum (2.70 m). This was mainly explained by 43.6% faster time (P <0.05) from the signal to the onset of force production. Greater vertical forces were observed with split step: 15.7% greater F(z) mean force (P <0.05), 60.0% greater F(z) peak force (P<0.01). In split step both mean (r= ? 0.813, P <0.01) and peak (r=?0.765, P <0.05) vertical forces (Fz) correlated negatively with the time from the onset of the force production to the photocell. With split step higher EMGs were observed in muscles responsible for ankle joint movement indicating that different strategies were used. Due to the split step the players were able to start the movement faster which mostly explains the advantages over the no-split step condition. Split step condition may also benefit from stretch shortening type of muscle action. 相似文献
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摘要：目的：研究8周负重振动训练对快速力量和下肢肌肉H反射的影响并探讨其可能的机制，以此丰富和完善负重振动训练的理论体系，并为普通人群和运动员振动力量训练方案的制定提供参考。方法：以16名男性田径专修大学生为研究对象，随机分为常规力量训练组（常规组）和振动力量训练组（振动组）。常规组完成30%1RM负重半蹲起训练，振动组附加振幅为2 mm、频率50 Hz的振动刺激，完成相同负重半蹲起训练。8周训练前后测定半蹲跳、原地纵跳和腓肠肌H反射。结果：常规组和振动组组内相对快速力量指数、原地纵跳绝对腾空高度和弹性能利用率均显著提高（P<0.05)。2组间相对快速力量指数、原地纵跳绝对腾空高度和弹性能利用率增加值均有显著性差异。组内H反射潜伏期和Hmax/Mmax减小且差异具有显著性；仅振动组H反射突触前抑制（PSI）升高且具有显著性。组间H反射潜伏期、Hmax/Mmax、PSI有显著性差异。结论：8周附加振动刺激的负重30%1RM力量训练对快速力量的提高优于相同负重的常规力量训练。8周负重振动力量训练的神经适应特征表现为H反射潜伏期、Hmax/Mmax下降和PSI的增强。 相似文献
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Abstract Motor pool excitability, H-reflex amplitude, was studied in RT responses preceded by varied foreperiods. Rapid plantar flexion of the foot followed auditory warning signals, varied foreperiods, and visual RT stimuli. Response speed was latency of EMG onset in the soleus muscle (PMT). The H-reflex stimulus was either omitted (none), or presented at one of three intervals in the movement response period: 0 (simultaneous with RT stimulus), 100 or 200 ms following stimulus. Control H-reflexes were taken before and after RT trials. The motor pool was not differentially excited following the random foreperiods. In fact it was not elevated over control values until late into the preparatory period (200 ms) which probably reflects the direct expression of the motor command. Using the H-reflex paradigm in combination with a RT response strongly altered the PMT when the H-reflex was presented early in the preparatory period (0). Since motor pool excitability changes were not evident early in the movement preparation period, they poorly predicted PMTs. 相似文献
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《European Journal of Sport Science》2013,13(1):69-79
Abstract The purpose of the present study was to examine whether static and dynamic balance control are related to neuromuscular function and ageing. For this purpose, we constructed a new dynamic balance measurement system that simulates natural falling. Ten young (age 21–31 years) and 20 elderly (age 60–70 years) men participated in the experiment. Maximal isometric torque (MVC) and activation level were measured from the quadriceps and plantar flexor muscles. The H-reflex, V-wave, and maximal M-wave were measured from the soleus muscle. In dynamic balance control, anterior-posterior centre-of-pressure swaying was 74±8.1 mm in the young men and 91.5±19.4 mm in the elderly men (P<0.05), whereas in the static condition there were no significant differences between the two groups. Knee extension MVC (young: 181±42 N·m; elderly: 135±39 N·m; P<0.01), torque after 500 ms (young: 147±36 N·m; elderly: 108±39 N·m; P<0.05), and activation level (young: 96.2±0.8%; elderly: 93.8±2.1%; P<0.01) were higher in the young than the elderly men; no differences were observed in plantar flexion. The amount of re-stabilization after a sudden disturbance seems to be an age-related phenomenon, which is seen as a connection between balance control and rapid force production. 相似文献
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Sidney Grosprêtre Thomas Jacquet Florent Lebon Charalambos Papaxanthis Alain Martin 《European Journal of Sport Science》2018,18(2):209-218
The neural mechanisms explaining strength increase following mental training by motor imagery (MI) are not clearly understood. While gains are mostly attributed to cortical reorganization, the sub-cortical adaptations have never been investigated. The present study investigated the effects of MI training on muscle force capacity and the related spinal and supraspinal mechanisms. Eighteen young healthy participants (mean age: 22.5?±?2.6) took part in the experiment. They were distributed into two groups: a control group (n?=?9) and an MI training group (n?=?9). The MI group performed seven consecutive sessions (one per day) of imagined maximal isometric plantar flexion (4 blocks of 25 trials per session). The control group did not engage in any physical or mental training. Both groups were tested for the isometric maximal plantar flexion torque (MVC) and the rate of torque development (RTD) before and after the training session. In addition, soleus and medial gastrocnemius spinal and supraspinal adaptations were assessed through the recording of H-reflexes and V-waves, with electrical stimulations of the posterior tibial nerve evoked at rest and during MVC, respectively. After one week, only the MI training group increased both plantar flexion MVC and RTD. The enhancement of muscle torque capacity was accompanied by significant increase of electromyographic activity and V-wave during MVC and of H-reflex at rest. The increased cortical descending neural drive and the excitability of spinal networks at rest could explain the greater RTD and MVC after one week of MI training. 相似文献
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