Muscle architecture and force-velocity relationships in humans

Abstract

The in vivo torque-velocity relationships of the knee extensors (KE), knee flexors (KF), ankle plantarflexors (PF), and ankle dorsiflexors (DF) were determined in 12 untrained subjects using an isokinetic testing device (Cybex II). These data were then matched to the predicted maximum forces and shortening velocities derived from muscle architectural determinations made on three hemipelvectomies (36). The torque-velocity curves of all muscle groups resembled that predicted by Hill's (19, 20) equation except at the higher forces and lower velocities. The peak torques occurred at mean velocities ranging from 41-62 rad X s-1 for the KE, KF, and PF. Although the peak torque of the DF occurred at the isometric loading condition, it was also lower than that predicted by Hill's equation. The muscle fiber length and physiological cross-sectional area measurements indicate that the architecture of the human leg musculature has a major influence on the torque-velocity characteristics. These data corroborate previous findings (24) that some neural inhibitory mechanism exists in the control of the leg musculature, which limits the maximum forces that could be produced under optimal stimulating conditions.

Muscle fascicle shortening behaviour of vastus lateralis during a maximal force–velocity test

“…However, when normalized to the optimal fibre length (i.e., in L 0 s −1 , with L 0 = 9.3 cm, Austin et al 2010), both maximal shortening velocities were similar (5.1 ± 2.2 and 6.2 ± 1.2 L 0 s −1 for VL and GM, respectively). The maximal shortening velocity of fascicle depends on the length of fascicle (here cancelled out by the normalization; Wickiewicz et al 1984) and the proportion of fast-twitch fibres (Barany 1967). Thus, considering the almost similar proportion of fast-twitch fibres in both muscles (Johnson et al 1973), our results are consistent.…”

Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body

“…Arrangement of PCSA and L f differed between the track sprinters and other cyclists, revealing a much larger PCSA but similar L f in the track sprinters. A long fascicle length (i.e., high numbers of sarcomeres in series) has theoretically been associated with high maximal muscle-fiber contraction velocity (63) and has been shown to relate to better sprint performance (14,15). PCSA is increased by muscle-fiber hypertrophy and is thought to result in proportional increases in maximal muscle force (27,64), assuming that specific force (F/ PCSA) remains constant.…”

A mechanism for increased contractile strength of human pennate muscle in response to strength training: changes in muscle architecture

“…As suggested by Edgerton et al (Wickiewicz et al 1983, Fukunaga et al 1996, CSA phys can be found from muscle volume, fibre length and fibre pennation angle. In the present calculations a muscle fibre length of 7 cm (Wickiewicz et al 1983(Wickiewicz et al , 1984 was used in combination with the muscle volumes and pennation angles obtained experimentally. Total muscle fibre force (F fibres ) was calculated from F quad /cos( p ), where quadriceps force (F quad ) was estimated from the measurement of maximal knee extension moment, assuming a 4.0 cm moment arm for the patella tendon (Wickiewicz et al 1984;Marshall et al 1990) and a ratio of patella tendon force to quadriceps tendon force of 0.70 at 70 deg knee flexion (Nisell et al 1989).…”