The effect of the magnitude of the impulse applied during the free oscillation technique in muscular and tendon stiffness around the ankle

• Autor(a) principal: Soares, Márcio Lopes
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Texto Completo: http://hdl.handle.net/10400.6/12100
• topic: Magnitude Impulso; Rigidez Muscular; Rigidez Tendinosa; Rigidez Tornozelo; Técnica Oscilação Livre

It has been reported that the impulse magnitude, during the free oscillation technique, can influence stiffness. However, is not clear whether both muscle and tendon stiffness can be affected similarly. Therefore, the aim of this study was to investigate if impulses of different magnitudes can affect the stiffness of muscle and/or tendon. Muscle and tendon stiffness were assessed using the free oscillation technique with three different impulse magnitudes (impulse 1, 2 and 3) associated respectively with the peak forces of 100, 150 and 200 N. Twenty-seven male college students (age 20.7 ± 1.3 years; height 1.73 ± 0.05 m; mass 74.7 ± 8.8 kg) volunteered for this study. It was found a significant decrease in “true” and “apparent” stiffness (p<0.0005) from impulse 1 (km = 630 ± 247 KN/m; Km = 296 ± 102 KN/m) to impulse 2 (km = 518 ± 208 KN/m; Km = 245 ± 89 KN/m) and from impulse 1 (km = 630 ± 247 KN/m; Km = 296 ± 102 KN/m) to impulse 3 (km = 566 ± 384 KN/m; Km = 265 ± 167 KN/m), respectively. However, no significant differences were found regarding “true” and “apparent” tendon stiffness. The present study results suggest that muscle stiffness (“true” and “apparent”) is affected by the impulse magnitude, but not tendon stiffness. The impulse magnitude may impact co-contraction and stretch reflex which in turn might affect the level of muscle stiffness.