Relationships between muscle lactate accumulation and surface EMG activities during isokinetic contractions in man

Horita, Tatsuya; Ishiko, Toshihiro

doi:10.1007/bf00696370

Cited by 112 publications

(76 citation statements)

References 20 publications

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“…A corollary of this interpretation is that assessments of neuromuscular performance by means of magnetic stimulation may offer greater insights into the performance capability that might be available to the sports performer in emergency situations where there is a critical level of threat to the stability of the joint system. Acute muscle fatigue induced by means of maximal voluntary muscle activation (MVMA) has the potential to cause dramatic increases in EMD; of between 42% to 70% longer compared with pre-fatigue values (Horita and Ishiko 1987; and concomitant decreases in the capacity for generating peak force. Temporal impairments of this type to the dynamic muscle stabilisers of the knee joint, may affect the ability to stabilise the knee during competitive match-play and place the sports performer at increased risk of injury.…”

Section: Introductionmentioning

confidence: 99%

Effects of acute fatigue on the volitional and magnetically-evoked electromechanical delay of the knee flexors in males and females

et al. 2007

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Neuromuscular performance capabilities, including those measured by evoked responses, may be adversely affected by fatigue; however, the capability of the neuromuscular system to initiate muscle force rapidly under these circumstances is yet to be established. Sex-differences in the acute responses of neuromuscular performance to exercise stress may be linked to evidence that females are much more vulnerable to ACL injury than males. Optimal functioning of the knee flexors is paramount to the dynamic stabilisation of the knee joint, therefore the aim of this investigation was to examine the effects of acute maximal intensity fatiguing exercise on the voluntary and magnetically-evoked electromechanical delay in the knee flexors of males and females. Knee flexor volitional and magnetically-evoked neuromuscular performance was assessed in seven male and nine females prior to and immediately after: (i) an intervention condition comprising a fatigue trial of 30-seconds maximal static exercise of the knee flexors, (ii) a control condition consisting of no exercise. The results showed that the fatigue intervention was associated with a substantive reduction in volitional peak force (PF V ) that was greater in males compared to females (15.0%, 10.2%, respectively, p < 0.01) and impairment to volitional electromechanical delay (EMD V ) in females exclusively (19.3%, p < 0.05).Similar improvements in magnetically-evoked electromechanical delay in males and females following fatigue (21%, p < 0.001), however, may suggest a vital facilitatory mechanism to overcome the effects of impaired voluntary capabilities, and a faster neuromuscular response that can be deployed during critical times to protect the joint system.

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Section: Introductionmentioning

confidence: 99%

Effects of acute fatigue on the volitional and magnetically-evoked electromechanical delay of the knee flexors in males and females

et al. 2007

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“…At such a velocity it may be necessary to sustain the effort for a longer period to identify the influence of the fatigue in SEMG parameters. Horita and Ishiko (1987) have verified that approximately 25 knee extensions at 180º/s are necessary to produce high levels of acidosis and, hence, significant changes in the SEMG indexes.…”

Section: °/S 180°/smentioning

confidence: 66%

“…Horita and Ishiko (1987) verified that the median frequency of SEMG signal decreased during isokinetic knee extensions performed for 30 s and 60 s. Molinari et al (2006) studied the manifestations of muscle fatigue during concentric extension-flexion and eccentric isokinetic movements of the knee; they also observed an accentuated decrease in MNF value due to fatigue process. Kellis (1999) assessed the SEMG in a knee extension isokinetic endurance test and reported an increment in the signal amplitude of the middle and the last repetitions in comparison to the values of the first contractions.…”

Section: Introductionmentioning

confidence: 70%

Study of muscle fatigue in isokinetic exercise with estimated conduction velocity and traditional electromyographic indicators

Schwartz

Bottaro

Celes

et al. 2014

Rev. Bras. Eng. Bioméd.

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Introduction: In the study of human biomechanics, it is often desirable to evaluate fatigue in the muscles that are involved in performing a particular task. Identifying the phenomena responsible for this condition is a problem that in most cases is complex and requires appropriate research mechanisms. Isokinetic dynamometry (ID) and surface electromyography (SEMG) are two techniques widely used in studies on strength and muscle fatigue. Their effectiveness is conditioned upon a good understanding of their limitations and the adoption of procedures to fully exploit the potential of each one. The main goal of the present study is to verify whether the electromyographic parameters, especially the conduction velocity (CV), are sensitive to the fatigue instauration process within sets of maximal isokinetic contractions. CV is a basic physiological parameter directly related to muscle activity and still little explored in experiments combining ID and SEMG. Methods: Instrumentation architecture that combines ID and SEMG was used to estimate electromyographic and biomechanical parameters in protocols of maximum intensity isokinetic knee extension exercises. This architecture allows for limiting the parameter estimates to a specifi c region of isokinetic exercise, called the isokinetic load range (ILR), where one can consider that the angular velocity is constant and the SEMG signals are cyclo-stationary. Electromyographic signals were acquired using an array of electrodes. Conclusion: The results suggest that CV and the other SEMG parameters, including amplitude and frequency descriptors, are sensitive to detect a fatigue process only in protocols that restrict the analysis to ILR and that also bring the subject to a state of fatigue quickly.

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“…However, it is still controversially debated which ion change causes this process. According to the recent literature the K+-ions seem to be the main factor responsible [1,9,14,18].…”

Section: Eble Os Et Al Tens-effekte Auf Die Kaumuskulaturmentioning

confidence: 99%

Transcutaneous electrical nerve stimulation (TENS): Its short-term and long-term effects on the masticatory muscles

Eble

Jonas

Kappert

2000

J Orofac Orthop/Fortschr Kieferorthop

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In an electromyographic study on subjects with no functional disturbances of the masticatory muscles, the duration of the post-therapeutic effects of transcutaneous electrical nerve stimulation (= TENS) on the superficial masseter and anterior temporal muscle was analyzed. The myoelectric signals were registered from 20 healthy volunteers in 3 different mandibular positions. The recordings were performed before a 20-minute TENS application with the J-4 Myomonitor and continued with a sequence of follow-up registrations with increasing interval to the initial stimulation. The EMG signals underwent computer-aided analysis and were evaluated by determining the integrated values as a parameter of muscle activity, and after Fourier transformation by 7 describing parameters of the power spectrum (e.g. mean power frequency = MPF). A detailed analysis of variance of all data was used to investigate significant changes of the parameters during the observation period. Muscular response to TENS includes a decrease in muscular activity (= reduction in integrated EMG signals) and a shift in the power spectrum to higher frequencies (increase in MPF). These changes were statistically highly significant for both analyzed muscles and for all different mandibular exercises. As these reactions to TENS are contrary to muscle fatigue, the results can be interpreted as indicating that this type of therapy stimulates a change in the biochemical and physiological muscular conditions, which leads to muscle relaxation. Electromyographically, the post-therapeutic effect lasted for 2 hours in case of normal masticatory muscle activity but for more than 7 hours in case of low muscular loading. The alterations of the integrated EMG values were more persistent than those of the parameters of the power spectrum.

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Relationships between muscle lactate accumulation and surface EMG activities during isokinetic contractions in man

Cited by 112 publications

References 20 publications

Effects of acute fatigue on the volitional and magnetically-evoked electromechanical delay of the knee flexors in males and females

Effects of acute fatigue on the volitional and magnetically-evoked electromechanical delay of the knee flexors in males and females

Study of muscle fatigue in isokinetic exercise with estimated conduction velocity and traditional electromyographic indicators

Transcutaneous electrical nerve stimulation (TENS): Its short-term and long-term effects on the masticatory muscles

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