Search results for "muscle-tendon"
showing 3 items of 13 documents
Concentric force enhancement during human movement
2001
In order to understand the possible mechanisms contributing to enhanced concentric performance in stretch-shortening cycle exercises in vivo the present study examined knee extension torque, EMG activity and fascicle length of the vastus lateralis muscle in maximal and submaximal human movements. Maximal concentric knee extensions (120 s-1) were done after pre-stretch and pre-isometric conditions by nine volunteers. During shortening at the knee angle of 115 (180 = extended) the knee extension torque was found to be greater in pre-stretch condition (272 vs. 248 Nm, p < 0.05) although the torque level prior to shortening was smaller than in pre-isometric condition (268 vs. 314 Nm, p< 0.05…
In vivo triceps surae and quadriceps femoris muscle function in a squat jump and counter movement jump
2000
An optic fibre method was used to measure in humans in vivo Achilles (ATF) and patellar tendon forces (PTF) during submaximal squat jumps (SJ) and counter movement jumps (CMJ). Normal two-legged jumps on a force plate and one-legged jumps on a sledge apparatus were made by four volunteers. Kinetics, kinematics, and muscle activity from seven muscles were recorded. The loading patterns of the tendomuscular system differed among the jumping conditions, but were similar when the jumping height was varied. Peak PTF were greater than ATF in each condition. In contrast to earlier simulation studies it was observed that tendomuscular force could continue to increase during the shortening of muscle…
Muscle-tendon mechanics and energetics during walking, running and jumping.
2012
In the human lower limb, muscles and tendon tend to interact in an efficient manner during common movements like walking, running and jumping. This pattern of interaction exploits the ability of muscles to produce forces efficiently at low shortening velocities, whilst tendons act as springs that help to store elastic energy during the contact phase, and return a large proportion of the energy in the pushoff phase. This pattern of muscletendon interaction can be disrupted in novel tasks or as a consequence of ageing or disease, resulting in a decrease in movement efficiency. peerReviewed