scholarly journals Activation of human plantar flexor muscles increases after electromyostimulation training

2002 ◽  
Vol 92 (4) ◽  
pp. 1383-1392 ◽  
Author(s):  
Nicola A. Maffiuletti ◽  
Manuela Pensini ◽  
Alain Martin
Keyword(s):  
Voluntary Activation ◽  
Emg Activity ◽  
Control Group ◽  
Neural Activation ◽  
Plantar Flexor ◽  
Postactivation Potentiation ◽  
Short Term ◽  
Flexor Muscles ◽  
Electrically Evoked Contractions ◽  
Plantar Flexor Muscles

Neuromuscular adaptations of the plantar flexor muscles were assessed before and subsequent to short-term electromyostimulation (EMS) training. Eight subjects underwent 16 sessions of isometric EMS training over 4 wk. Surface electromyographic (EMG) activity and torque obtained under maximal voluntary and electrically evoked contractions were analyzed to distinguish neural adaptations from contractile changes. After training, plantar flexor voluntary torque significantly increased under isometric conditions at the training angle (+8.1%, P< 0.05) and at the two eccentric velocities considered (+10.8 and +13.1%, P < 0.05). Torque gains were accompanied by higher normalized soleus EMG activity and, in the case of eccentric contractions, also by higher gastrocnemii EMG ( P < 0.05). There was an 11.9% significant increase in both plantar flexor maximal voluntary activation ( P < 0.01) and postactivation potentiation ( P < 0.05), whereas contractile properties did not change after training. In the absence of a change in the control group, it was concluded that an increase in neural activation likely mediates the voluntary torque gains observed after short-term EMS training.

Specific modulation of spinal and cortical excitabilities during lengthening and shortening submaximal and maximal contractions in plantar flexor muscles

2014 ◽  
Vol 117 (12) ◽  
pp. 1440-1450 ◽  
Author(s):  
Julien Duclay ◽  
Benjamin Pasquet ◽  
Alain Martin ◽  
Jacques Duchateau
Keyword(s):  
Muscle Activation ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
H Reflex ◽  
Medial Gastrocnemius ◽  
Emg Activity ◽  
Plantar Flexor ◽  
Lengthening Contractions ◽  
Flexor Muscles ◽  
Plantar Flexor Muscles

This study investigated the influence of the torque produced by plantar flexor muscles on cortical and spinal excitability during lengthening and shortening voluntary contractions. To that purpose, modulations of motor-evoked potential (MEP) and Hoffmann (H) reflex were compared in the soleus (SOL) and medial gastrocnemius (MG) during anisometric submaximal and maximal voluntary contraction (MVC) of the plantar flexor muscles. For the submaximal shortening and lengthening contractions, the target torque was set at 50% of their respective MVC force. The results indicate that the amplitudes of both MEP and H-reflex responses, normalized to the maximal M wave, were significantly ( P < 0.05) lower during lengthening compared with shortening submaximal contraction. For these two parameters, the reduction reached, respectively, 22.1 and 31.9% for the SOL and 34.5 and 29.3% for the MG. During MVC, normalized MEP and H reflex of the SOL were both reduced significantly by 19.9% ( P < 0.05) and 29.9% ( P < 0.001) during lengthening and shortening contraction, respectively, whereas no significant change ( P > 0.05) was observed for MG. In addition, the silent period in the ongoing electromyogram (EMG) activity following the MEP was significantly ( P < 0.01) briefer during lengthening than shortening contractions but did not differ ( P > 0.05) between contraction intensities and muscles. Together, these results indicate that cortical and spinal mechanisms involved in the modulation of muscle activation during shortening and lengthening contractions differ between synergistic muscles according to the torque produced. Data further document previous studies reporting that the specific modulation of muscle activation during lengthening contraction is not torque dependent.

Comparison of Twitch-Contractile Properties of Plantar-Flexor Muscles in Young and 52- to 63-Year-Old Men

2002 ◽  
Vol 10 (2) ◽  
pp. 160-168 ◽  
Author(s):  
Mati Pääsuke ◽  
Jaan Ereline ◽  
Helena Gapeyeva ◽  
Heigo Maamägi
Keyword(s):  
Middle Age ◽  
Voluntary Contraction ◽  
Contractile Properties ◽  
Plantar Flexor ◽  
Postactivation Potentiation ◽  
Force Development ◽  
Flexor Muscles ◽  
Contraction Times ◽  
Old Men ◽  
Plantar Flexor Muscles

This study compared maximal voluntary-contraction (MVC) force and twitch-contractile properties of the plantar-flexor muscles in resting and postactivation potentiation slates of 2 groups of men matched for similar levels of physical activity: young (19- to 22-year-olds. n = 13) and 52–63 years old (n = 12). MVC force, twitch peak force (PT), maximal rates of force development and relaxation, and postactivation potentiation were higher (p < .05) in young than in 52- to 63-year-old men. In young men. potentiated-twitch PT was 23.3% higher (p < .01) than resting twitch. Resting- and potentialed-twitch-contraction times were 16.7% and 18.3% shorter, respectively (p < .001), in young than in 52- to 63-year-old men. These Findings suggest that late middle age is characterized by reduced capacity for evoked twitch-force generation and potentiation and slowed speed of contraction of the plantar-flexor muscles.

Acute effect of muscle stretching on the steadiness of sustained submaximal contractions of the plantar flexor muscles

2011 ◽  
Vol 110 (2) ◽  
pp. 407-415 ◽  
Author(s):  
Emika Kato ◽  
Stéphanie Vieillevoye ◽  
Costantino Balestra ◽  
Nathalie Guissard ◽  
Jacques Duchateau
Keyword(s):  
Acute Effect ◽  
Medial Gastrocnemius ◽  
Matching Task ◽  
Emg Activity ◽  
Plantar Flexor ◽  
Fascicle Length ◽  
Muscle Stretching ◽  
Flexor Muscles ◽  
Two Parameters ◽  
Plantar Flexor Muscles

This paper examines the acute effect of a bout of static stretches on torque fluctuation during an isometric torque-matching task that required subjects to sustain isometric contractions as steady as possible with the plantar flexor muscles at four intensities (5, 10, 15, and 20% of maximum) for 20 s. The stretching bout comprised five 60-s passive stretches, separated by 10-s rest. During the torque-matching tasks and muscle stretching, the torque (active and passive) and surface electromyogram (EMG) of the medial gastrocnemius (MG), soleus (Sol), and tibialis anterior (TA) were continuously recorded. Concurrently, changes in muscle architecture (fascicle length and pennation angle) of the MG were monitored by ultrasonography. The results showed that during stretching, passive torque decreased and fascicle length increased gradually. Changes in these two parameters were significantly associated ( r2 = 0.46; P < 0.001). When data from the torque-matching tasks were collapsed across the four torque levels, stretches induced greater torque fluctuation ( P < 0.001) and enhanced EMG activity ( P < 0.05) in MG and TA muscles with no change in coactivation. Furthermore, stretching maneuvers produced a greater decrease (∼15%; P < 0.001) in fascicle length during the torque-matching tasks and change in torque fluctuation (CV) was positively associated with changes in fascicle length ( r2 = 0.56; P < 0.001), MG and TA EMG activities, and coactivation ( r2 = 0.35, 0.34, and 0.35, respectively; P < 0.001). In conclusion, these observations indicate that repeated stretches can decrease torque steadiness by increasing muscle compliance and EMG activity of muscles around the joint. The relative influence of such adaptations, however, may depend on the torque level during the torque-matching task.

scholarly journals The single-leg heel raise does not predict maximal plantar flexion strength in healthy males and females

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0253276
Author(s):  
Lauren K. Sara ◽  
Savannah B. Gutsch ◽  
Sandra K. Hunter
Keyword(s):  
Sex Differences ◽  
Plantar Flexion ◽  
Voluntary Activation ◽  
Plantar Flexor ◽  
Maximal Strength ◽  
Flexor Muscles ◽  
Males And Females ◽  
Flexion Strength ◽  
Plantar Flexor Muscles ◽  
Flexor Strength

Introduction The single-leg heel raise test (SLHR) is commonly used in clinical settings to approximate plantar flexor strength, yet this is neither validated nor supported physiologically. The purposes of this study were to: determine (1) associations between SLHR repetitions, maximal plantar flexor strength, and reductions in strength; and (2) whether sex differences exist in performance of the SLHR. Methods Twenty-eight young, healthy participants (14 males,14 females, 19–30 years) performed repeated single-leg heel raises to task failure. Pre- and post-task measures included maximal voluntary isometric contractions (MVIC), and voluntary activation and contractile properties of the plantar flexor muscles, assessed using peripheral electrical stimulation of the tibial nerve. Surface electromyography was recorded for the medial and lateral gastrocnemius, soleus, and anterior tibialis muscles. Results The SLHR resulted in 20.5% reductions in MVIC torque (p<0.001). However, the number of SLHR repetitions was not correlated with either the baseline MVIC (maximal strength; p = 0.979) or the reduction in MVIC following the SLHR (p = 0.23). There were no sex differences in either the number of SLHR repetitions (p = 0.14), baseline MVIC torque (p = 0.198), or the reduction of MVIC (p = 0.14). MVIC decline was positively associated with the reduction in voluntary activation (r = 0.841, p<0.001), but was not associated with the change in twitch amplitude (p = 0.597). Conclusions The SLHR was similar in young males and females yet was a poor predictor of maximal plantar flexor strength but evaluates performance fatigability of the lower extremity specific to dynamic contractions. The reduction in maximal strength at task failure was explained by reduced neural drive to the plantar flexor muscles in both males and females. Impact statement SLHR performance is not a clinical assessment of plantar flexor strength but assesses dynamic lower extremity fatigability that is similar in males and females. Alternate clinical measures for maximal plantar flexion strength need to be developed.

scholarly journals Effect of footwear on intramuscular EMG activity of plantar flexor muscles in walking

2020 ◽  
Vol 55 ◽  
pp. 102474
Author(s):  
Annamária Péter ◽  
Anton Arndt ◽  
András Hegyi ◽  
Taija Finni ◽  
Eva Andersson ◽  
...  
Keyword(s):  
Emg Activity ◽  
Plantar Flexor ◽  
Flexor Muscles ◽  
Plantar Flexor Muscles

scholarly journals Comparison Between High- and Low-Intensity Static Stretching Training Program on Active and Passive Properties of Plantar Flexors

2021 ◽  
Vol 12 ◽  
Author(s):  
Masatoshi Nakamura ◽  
Riku Yoshida ◽  
Shigeru Sato ◽  
Kaoru Yahata ◽  
Yuta Murakami ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Intervention Group ◽  
Muscle Stiffness ◽  
Control Group ◽  
Plantar Flexor ◽  
Static Stretching ◽  
Drop Jump ◽  
Low Intensity ◽  
Flexor Muscles ◽  
Plantar Flexor Muscles

The purpose of this study was to compare two static stretching (SS) training programs at high-intensity (HI-SS) and low-intensity (LI-SS) on passive and active properties of the plantar flexor muscles. Forty healthy young men were randomly allocated into three groups: HI-SS intervention group (n = 14), LI-SS intervention group (n = 13), and non-intervention control group (n = 13). An 11-point numerical scale (0–10; none to very painful stretching) was used to determine SS intensity. HI-SS and LI-SS stretched at 6–7 and 0–1 intensities, respectively, both in 3 sets of 60 s, 3×/week, for 4 weeks. Dorsiflexion range of motion (ROM), gastrocnemius muscle stiffness, muscle strength, drop jump height, and muscle architecture were assessed before and after SS training program. The HI-SS group improved more than LI-SS in ROM (40 vs. 15%) and decreased muscle stiffness (−57 vs. −24%), while no significant change was observed for muscle strength, drop jump height, and muscle architecture in both groups. The control group presented no significant change in any variable. Performing HI-SS is more effective than LI-SS for increasing ROM and decreasing muscle stiffness of plantar flexor muscles following a 4-week training period in young men. However, SS may not increase muscle strength or hypertrophy, regardless of the stretching discomfort intensity.

Comparison of Twitch Contractile Properties of Plantar Flexor Muscles in 9–10-Year-Old Girls and Boys

2003 ◽  
Vol 15 (3) ◽  
pp. 324-332 ◽  
Author(s):  
Mati Pääsuke ◽  
Jaan Ereline ◽  
Helena Gapeyeva ◽  
Madli Toots ◽  
Laivi Toots
Keyword(s):  
Skeletal Muscles ◽  
Relaxation Times ◽  
Voluntary Contraction ◽  
Contractile Properties ◽  
Maximal Rate ◽  
Plantar Flexor ◽  
Postactivation Potentiation ◽  
Flexor Muscles ◽  
Contraction And Relaxation ◽  
Plantar Flexor Muscles

Twitch contractile properties of plantar flexor muscles were compared in 9- to 10-year-old girls and boys. No significant gender differences (p > .05) in isometric maximal voluntary contraction force and twitch peak force, contraction and relaxation times, and twitch maximal rate of force development in either resting or potentiated state have been observed. However, boys had significantly greater (p < .05) twitch postactivation potentiation and potentiated twitch maximal rate of relaxation than girls. These results indicated that twitch force-potentiation capacity of skeletal muscles prior to puberty is more highly developed in boys than girls.

scholarly journals Ultrasound-derived changes in thickness of human ankle plantar flexor muscles during walking and running are not homogeneous along the muscle mid-belly region

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
E. F. Hodson-Tole ◽  
A. K. M. Lai
Keyword(s):  
Statistical Parametric Mapping ◽  
Muscle Thickness ◽  
Ultrasound Images ◽  
Plantar Flexor ◽  
Image Region ◽  
Thickness Change ◽  
Musculoskeletal Models ◽  
Flexor Muscles ◽  
Anatomical Space ◽  
Plantar Flexor Muscles

Abstract Skeletal muscle thickness is a valuable indicator of several aspects of a muscle’s functional capabilities. We used computational analysis of ultrasound images, recorded from 10 humans walking and running at a range of speeds (0.7–5.0 m s−1), to quantify interactions in thickness change between three ankle plantar flexor muscles (soleus, medial and lateral gastrocnemius) and quantify thickness changes at multiple muscle sites within each image. Statistical analysis of thickness change as a function of stride cycle (1d statistical parametric mapping) revealed significant differences between soleus and both gastrocnemii across the whole stride cycle as they bulged within the shared anatomical space. Within each muscle, changes in thickness differed between measurement sites but not locomotor condition. For some of the stride, thickness measures taken from the distal-mid image region represented the mean muscle thickness, which may therefore be a reliable region for these measures. Assumptions that muscle thickness is constant during a task, often made in musculoskeletal models, do not hold for the muscles and locomotor conditions studied here and researchers should not assume that a single thickness measure, from one point of the stride cycle or a static image, represents muscle thickness during dynamic movements.

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