Effect of muscle length on voluntary activation of the plantar flexors in boys and men

• Published in: European journal of applied physiology 2016-05, Vol.116 (5), p.1043-1051
• Main Authors: Kluka, Virginie, Martin, Vincent, Vicencio, Sebastian Garcia, Giustiniani, Mathias, Morel, Claire, Morio, Cédric, Coudeyre, Emmanuel, Ratel, Sébastien
• Format: Article
• Language: English
• Subjects: Adult; Ankle - physiology; Ankle Joint - physiology; Biomedical and Life Sciences; Biomedicine; Child; Children & youth; Compliance; Electromyography - methods; Human health and pathology; Human Physiology; Humans; Isometric Contraction - physiology; Leg - physiology; Life Sciences; Male; Muscle Strength - physiology; Muscle, Skeletal - physiology; Occupational Medicine/Industrial Medicine; Original Article; Sports Medicine; Tissues and Organs; Torque; Young Adult
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s00421-016-3362-6

Purpose The aim of the present study was to compare the effect of muscle length on the maximal voluntary activation level (VA) of the plantar-flexors between children and adults. Methods Fourteen boys (10.0 ± 1.0 years) and fifteen men (24.6 ± 4.2 years) performed 5-s maximal isometric voluntary contractions (MVC) of the plantar-flexor muscles at seven ankle angles [from 10° in dorsi-flexion (DF) to 20° in plantar-flexion (PF); 0° = reference position; the angle between the plantar surface and leg is a right angle]. Single magnetic stimulations were delivered to the posterior tibial nerve during MVCs to determine VA. Results Results showed a higher absolute torque of the plantar-flexor muscles at long (10° DF) than at short muscle length (20° PF) in men (89.4 ± 19.4 vs. 46.8 ± 17.0 N m, P