Joint-specific power absorption during eccentric cycling

Background: Previous investigators have reported that long term eccentric cycling increases muscle size and strength in a variety of populations. The joint-specific strategies used to absorb power during eccentric cycling, however, have not been identified. The purpose of this investigation was to determine the extent to which ankle, knee, and hip joint actions absorb power during eccentric cycling. Methods: Eight active males resisted the reverse moving pedals of an isokinetic eccentric ergometer (60 rpm) while targeting 20% of their maximum concentric cycling power. Pedal reaction forces and joint kinematics were recorded with an instrumented pedal and instrumented spatial linkage system, respectively. joint powers were calculated using inverse dynamics; averaged over complete crank revolutions and over extension and flexion phases: and differences were assessed with a one-way ANOVA. Findings: Ankle, knee, and hip joint actions absorbed 10 (SD 3)%, 58 (SD 8)%, and 29 (SD 9)% of the total power, respectively, with 3 (SD 1)% transferred across the hip. The main power absorbing actions were eccentric knee extension (-139 (SD 21) watts), eccentric hip extension (-51 (SD 31) watts), and eccentric hip flexion (-25 (SD 6) watts). Interpretation: Eccentric cycling was performed with a combination of knee and hip joint actions which is consistent with submaximal concentric cycling. These data support and extend previous work that eccentric cycling improves knee extensor function and hip extensor muscle cross sectional area. Such information may allow clinicians to take even greater advantage of eccentric cycling as a rehabilitation modality. (C) 2009 Elsevier Ltd. All rights reserved.