THE INFLUENCE OF BODY POSITION ON LOAD RANGE DURING ISOKINETIC KNEE EXTENSION/FLEXION

Isokinetic range of motion (ROM) has three distinct phases: rate of velocity development (RVD), load
range (LR), and deceleration (DCC). The purpose of this study was to determine if differences in
isokinetic knee extension/flexion LR exist between body positions. Ten subjects (4 males and 6 females,
age 29.3 ± 5.4 yrs, ht 1.71 ± 0.10 m, wt 71.9 ± 12.9 kg) volunteered to participate in the seated vs. prone
investigation and nine different subjects (4 males and 5 females, age 29.5 ± 6.9 yrs, ht 1.72 ± 0.09 m, wt
69.0 ± 13.8 kg) volunteered to participate in the seated vs. supine study. Each subject completed 3
maximal reciprocal concentric/concentric repetitions of dominant knee extension/flexion on a Biodex
System 2 isokinetic dynamometer at 60, 120, 180, 240 and 360 deg·sec-1 in the supine or prone and
seated positions. Repeated measures ANOVA revealed that only seated flexion at 360 deg·sec-1 (57.6 ±
1.7 degrees) elicited significantly (p < 0.05) greater LR than prone (49.2 ± 2.8 degrees). No significant
differences in LR extension or flexion existed at any velocity between the supine vs. seated positions.
ANOVA also demonstrated differences between seated vs. prone torque, work and power at most
velocities while there was no difference between seated vs. supine. LR is the only phase of an isokinetic
repetition where quantifiable resistance is maintained and this data appears to support that it may not be
position-dependent but position may alter traditional performance variables.