title: Fatigue and optimal conditions for short-term work capacity.
abstract: There is an optimal load and corresponding velocity at which peak power output occurs. It is reasonable to expect that these conditions will change as a result of fatigue during 30 s of all-out cycling. This study evaluated optimal velocity after 30 s of maximal isokinetic cycle ergometer exercise and tested the hypothesis that progressive adjustment of velocity (optimized) during 30 s of all-out cycling would permit greater short-term work capacity (STWC). Non-fatigued optimal cadence [NF(OC), 109.6 (2.5) rpm] was determined for ten males on an SRM ergometer using regression analysis of the torque-angular velocity relation during a 7-s maximal acceleration. Fatigued optimal cadence [73.4 (2.4) rpm] was determined in the same way, immediately after a 30-s isokinetic test at NF(OC). A subsequent trial with cadence decreasing in steps from NF(OC) to a conservative estimate of fatigued optimal cadence [83.9 (2.8) rpm] was completed to see if more work could be done with a more optimal cadence during the test. STWC was not different ( P=0.50) between the constant [23,681 (764) J] and optimized [23,679 (708) J] conditions. Another more radical progressive change in cadence with four subjects yielded the same result (no increase in STWC). Extraneous factors apparently contribute more to variability in STWC than differences between constant and adjusted optimization of conditions.
authors.affiliation: Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, T2N 1N4, Calgary, Alberta, Canada. brian@kin.ucalgary.ca
authors.forename: Brian R
authors.initials: BR
authors.lastname: MacIntosh
authors.forename: Krista
authors.initials: K
authors.lastname: Svedahl
authors.forename: Minhan
authors.initials: M
authors.lastname: Kim
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D004734:Energy Metabolism / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D016014:Linear Models; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*