Motor Unit and Motoneurone Excitability during Explosive Movement

Moritani, Toshio

doi:10.1002/9780470757215.ch3

Cited by 26 publications

(27 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The RFD is thought to be directly related to success in sport performances involving explosive types of muscle actions (Aagaard et al 2002;Andersen and Aagaard 2006;Behm and Sale 1993;HaV et al 2005;Kawamori et al 2006;Mirkov et al 2004;Moritani 2002) and is often used as an outcome measure associated with power-related exercises (HaV et al 2005;Kawamori et al 2006;Mirkov et al 2004;Murphy et al 1994;Stone et al 2004;Viitasalo and Aura 1984). For example, Kawamori et al (2006) reported that the RFD was correlated (r = 0.65-0.74) with explosive performance such that as dynamic RFD increased, vertical jump performance also increased, suggesting that athletes who exhibit greater RFD may be able to jump higher.…”

Section: Discussionmentioning

confidence: 98%

Acute effects of passive stretching on the electromechanical delay and evoked twitch properties

et al. 2009

View full text Add to dashboard Cite

The purpose of this study was to investigate the acute effects of passive stretching on the electromechanical delay (EMD), peak twitch force (PTF), rate of force development (RFD), and compound muscle action potential (M-wave) amplitude during evoked twitches of the plantar flexor muscles. 16 men (mean age +/- SD = 21.1 +/- 1.7 years; body mass = 75.9 +/- 11.4 kg; height = 176.5 +/- 8.6 cm) participated in this study. A single, square-wave, supramaximal transcutaneous electrical stimulus was delivered to the tibial nerve before and after passive stretching. The stretching protocol consisted of nine repetitions of passive assisted stretching designed to stretch the calf muscles. Each repetition was held for 135 s separated by 5-10 s of rest. Dependent-samples t tests (pre- vs. post-stretching) were used to analyze the EMD, PTF, RFD, and M-wave amplitude data. There were significant changes (P < or = 0.05) from pre- to post-stretching for EMD (mean +/- SE = 4.84 +/- 0.31 and 6.22 +/- 0.34 ms), PTF (17.2 +/- 1.3 and 15.6 +/- 1.5), and RFD (320.5 +/- 24.5 and 279.8 +/- 28.2), however, the M-wave amplitude did not change (P > 0.05). These findings suggested that passively stretching the calf muscles affected the mechanical aspects of force production from the onset of the electrically evoked twitch to the peak twitch force. These results may help to explain the mechanisms underlying the stretching-induced force deficit that have been reported as either "mechanical" or "electrical" in origin.

show abstract

Section: Discussionmentioning

confidence: 98%

Acute effects of passive stretching on the electromechanical delay and evoked twitch properties

et al. 2009

View full text Add to dashboard Cite

show abstract

“…However, scientific facts argue against ''the idea of exclusive fiber type recruitment'' [69]. According to intramuscular electromyographic studies, the maximal recruitment domain differs among muscles of different sizes because of the different fiber type composition [163].…”

Section: Possible Physiological Adaptation Differencesmentioning

confidence: 99%

“…Motor unit recruitment appears to be essentially complete at approximately 50 % of the maximal voluntary contraction (MVC) in small muscles (e.g., adductor pollicis) with mainly type I fibers and continues until 80-90 % MVC in larger muscles (e.g., biceps brachii, brachialis, and deltoid muscles) composed of both type I and II fibers [163,164]. ''Small muscles may therefore be at increased risk for overtraining despite the implementation of light workouts because many FT (fast twitch) fibers are recruited even with light resistance'' [69].…”

Section: Possible Physiological Adaptation Differencesmentioning

confidence: 99%

Short-term Periodization Models: Effects on Strength and Speed-strength Performance

Hartmann

Wirth

Keiner³

et al. 2015

Sports Med

View full text Add to dashboard Cite

Dividing training objectives into consecutive phases to gain morphological adaptations (hypertrophy phase) and neural adaptations (strength and power phases) is called strength-power periodization (SPP). These phases differ in program variables (volume, intensity, and exercise choice or type) and use stepwise intensity progression and concomitant decreasing volume, converging to peak intensity (peaking phase). Undulating periodization strategies rotate these program variables in a bi-weekly, weekly, or daily fashion. The following review addresses the effects of different short-term periodization models on strength and speed-strength both with subjects of different performance levels and with competitive athletes from different sports who use a particular periodization model during off-season, pre-season, and in-season conditioning. In most periodization studies, it is obvious that the strength endurance sessions are characterized by repetition zones (12-15 repetitions) that induce muscle hypertrophy in persons with a low performance level. Strictly speaking, when examining subjects with a low training level, many periodization studies include mainly hypertrophy sessions interspersed with heavy strength/power sessions. Studies have demonstrated equal or statistically significant higher gains in maximal strength for daily undulating periodization compared with SPP in subjects with a low to moderate performance level. The relatively short intervention period and the lack of concomitant sports conditioning call into question the practical value of these findings for competitive athletes. Possibly owing to differences in mesocycle length, conditioning programs, and program variables, competitive athletes either maintained or improved strength and/or speed-strength performance by integrating daily undulating periodization and SPP during off-season, pre-season and in-season conditioning. In high-performance sports, high-repetition strength training (>15) should be avoided because it does not provide an adequate training stimulus for gains in muscle cross-sectional area and strength performance. High-volume circuit strength training performed over 2 years negatively affected the development of the power output and maximal strength of the upper extremities in professional rugby players. Indeed, meta-analyses and results with weightlifters, American Football players, and throwers confirm the necessity of the habitual use of ≥80% 1 RM: (1) to improve maximal strength during the off-season and in-season in American Football, (2) to reach peak performance in maximal strength and vertical jump power during tapering in track-and-field, and (3) to produce hypertrophy and strength improvements in advanced athletes. The integration and extent of hypertrophy strength training in in-season conditioning depend on the duration of the contest period, the frequency of the contests, and the proportion of the conditioning program. Based on the literature, 72 h between hypertrophy strength training and strength-power training should be pr...

show abstract

“…The rate of force development (RFD) prior to peak force has been well examined because of its impact on several human movements, e.g., explosive sports (Moritani 2002) and postural balance in elderly (Pijnappels et al 2005;Thelen et al 1996). The RFD is known to increase after explosive resistance training (Aagaard et al 2002;Behm and Sale 1993a;Hakkinen et al 1985;Hakkinen and Komi 1986;Van Cutsem et al 1998), and is often attributed to neural factors like increased doublet discharges (Van Cutsem et al 1998) and Wring rate (Patten et al 2001).…”

Section: Introductionmentioning

confidence: 97%

The effect of rate of force development on maximal force production: acute and training-related aspects

et al. 2007

View full text Add to dashboard Cite

The force generated during a maximal voluntary contraction (MVC) is known to increase by resistance training. Although this increase cannot be solely attributed to changes in the muscle itself, many studies examining muscle activation at peak force failed to detect neural adaptations with resistance training. However, the activation prior to peak force can have an impact on maximal force generation. This study aims at investigating the role of rate of force development (RFD) on maximal force during resistance training. Fourteen subjects carried out 5 days of isometric resistance training with dorsiflexion of the ankle with the instruction to generate maximal force. In a second experiment, 18 subjects performed the same task with the verbal instruction to generate maximal force (instruction I) and to generate force as fast and forcefully as possible (instruction II). The main findings were that RFD increased twice as much as the 16% increase in maximal force with training, with a positive association between RFD and force within the last session of training and between training sessions. Instruction II generated a higher RFD than instruction I, with no difference in maximal force. These findings suggest that the positive association between RFD and maximal force is not causal, but is mediated by a third factor. In the discussion, we argue for the third factor to be physiological changes affecting both aspects of a MVC or different processes affecting RFD and maximal force separately, rather than a voluntary strategic change of both aspects of MVC.

show abstract

Motor Unit and Motoneurone Excitability during Explosive Movement

Cited by 26 publications

References 62 publications

Acute effects of passive stretching on the electromechanical delay and evoked twitch properties

Acute effects of passive stretching on the electromechanical delay and evoked twitch properties

Short-term Periodization Models: Effects on Strength and Speed-strength Performance

The effect of rate of force development on maximal force production: acute and training-related aspects

Contact Info

Product

Resources

About