Joint-specific power loss after eccentric exercise.
Previous investigators have reported changes in maximal power after eccentric exercise. The influence of eccentric joint-specific power absorption on subsequent concentric joint-specific power production during multijoint actions has not been reported.


OBJECTIVE
Our purposes were to determine the extent to which ankle, knee, and hip joint actions absorbed power during eccentric cycling (ECCcyc) and to evaluate changes in power produced by those joint actions during subsequent maximal concentric cycling (CONcyc). We hypothesized that joint actions that absorbed the most power during ECCcyc would exhibit the greatest reductions in power during subsequent maximal CONcyc.


METHODS
Nineteen cyclists performed baseline trials of maximal single-leg CONcyc immediately before and 24 h after acute single-leg ECCcyc (5 min, 40% maximum single-leg CONcyc power). Pedal forces and limb kinematics were determined with a force-sensing pedal and instrumented spatial linkage system, respectively. Joint-specific powers were calculated using inverse dynamics and averaged over complete crank revolutions and over extension and flexion phases.


RESULTS
The largest power-absorbing actions during ECCcyc were eccentric knee extensor activity (-185 +/- 12 W) followed by eccentric hip extensor activity (-92 +/- 12 W). Power absorbed through ankle joint actions was small (-10 +/- 2 W). At 24 h, pedal power produced during maximal CONcyc was reduced by 11% +/- 3% relative to baseline. Compared with baseline, knee extension power was reduced by 19% +/- 0 7%, whereas hip extension power did not differ.


CONCLUSIONS
Power absorbed through eccentric knee extension actions significantly reduced knee extension power produced during subsequent maximal CONcyc. Even with reduced knee extensor function, participants were able to deliver 89% of their baseline power to the environment. These results have implications for individuals who must continue to perform multijoint activities after eccentric exercise.
Elmer
Steven J
SJ
Department of Exercise and Sport Science, University of Utah, 250 S 1850 E Room 241, Salt Lake City, UT 84112-0920, USA. steve.elmer@utah.edu
Martin
James C
JC
D000328:Adult; D000843:Ankle Joint / Q000502:physiology*; D056352:Athletes; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D015444:Exercise / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D055815:Young Adult