Kinematics of Biophysically Asymmetric Limbs Within Rate of Velocity Development

Abstract

The purpose of this study was to investigate the movement speed characteristics of 2 intrinsically different limbs. Twenty subjects volunteered to participate (10 men and 10 women). Each subject performed 5 repetitions of concentric knee and elbow extension and flexion movements at 60 through 500 d.s(-1) on an isokinetic dynamometer. Kinematic data were collected at 1,000 Hz and separated into rate of velocity development (RVD) and peak torque. Results demonstrated a significant (p < 0.05) main effect for sex for RVD and peak torque. Significant (p < 0.05) differences were also demonstrated between knee and elbow RVD and between knee and elbow peak torque at every speed tested. Neither knee and elbow RVD nor peak torque demonstrated any significant Pearson correlations at any speed tested (r = -0.17-0.41). These results collectively point to the specificity of limb speed and torque as a result of biophysical differences such as length and mass. Therefore, strength and speed may be modulated by neuromotor patterns that differ based on individual limbs.

Knee extension rate of velocity development affects walking performance differently in men and women

“…Rate of velocity development (RVD) is a metric of acceleration capacity during initial muscle contraction that is usually estimated from the time-velocity curve during the unloaded acceleration phase of isokinetic testing (3, 4). RVD can be operationally defined as the time required to reach a predetermined angular velocity(3).…”

“…RVD can be operationally defined as the time required to reach a predetermined angular velocity(3). The relationships between RVD at various predetermined angular velocities and peak torques are weak (r=−0.09 to −0.29), suggesting that RVD captures a different aspect of muscle function than peak torque (4). In adults who are physically active, shortterm velocity-specific training causes improvement of knee extension RVD, with little or no improvement in knee extension peak torque (3, 17).…”