Why do muscles lose torque potential when activated within their agonistic group?

• DOI: 10.1242/jeb.213843
• Publication Date: 2019-12-03T15:35:29Z
• Authors: Heiliane de Brito...; Daiani de Campos; Andrew Sawatsky; Seong-won Han; Walter Herzog
• Keywords: 03 medical and health sciences; 0302 clinical medicine; Torque; Animals; Female; Rabbits; Muscle, Skeletal; Biomechanical Phenomena

Agonistic muscles lose approximately 20% of their individual torque generating capacity when activated with agonistic compared to stimulated in isolation. In this study, we (i) tested if loss was accompanied by a corresponding force, thereby testing the potential role changes moment arms between conditions; (ii) removed all inter-muscular connections quadriceps muscles, thus determining force transmission; and (iii) systematically changed pressure performing experiments at different activation/force levels, exploring possible simultaneous muscle activation. Experiments were performed New Zealand White rabbit model (n=5). Torque measured during activation femoral nerve branches that supply while activating these simultaneously Regardless joint angle differences values isolated also observed for directly values. Mean remained similar intact separated conditions: difference (21±5% maximum isometric condition [MICtorque], versus 19±6% MICtorque respectively) (18±3% MICforce 19±7% respectively). The absolute independent presumably pressures. Based on results, conclude neither arm, nor transmission seems be primary cause deficit mechanisms underlying contraction remain unknown.