Affiliations: [a] Center for Exercise Science, College of Health and
Human Performance, University of Florida, PO Box 112805, Gainesville, FL
32611-8205, USA | [b] Department of Physiology, College of Medicine,
University of Florida, 1600 SW Archer Road, Gainesville, FL 32610-0274,
USA
Note: [] Department of Physiology, College of Medicine, University of
Florida, 1600 SW Archer Road, 100274, Gainesville, FL 32610-0274, USA. Tel.: +1
352 392 4480; Fax: +1 352 846 0270; E-mail: stevens@phys.med.ufl.edu
Abstract: A variety of isokinetic fatigue protocols have been previously
reported in the literature. The purpose of this study was to examine a new
protocol to objectively quantify dynamic concentric and eccentric muscle
performance in individuals, or in a multiple subject group, under conditions of
acute exhaustive exercise. Pre-fatigue maximal peak torque (PT) and
peri-fatigue PT values were measured in unilateral dominant leg quadriceps
femoris of human subjects using an isokinetic dynamometer. The protocol was
based on single-velocity (90^{\circ}/s) reciprocal-mode
concentric/eccentric (CON/ECC) contractions fixed at 35 repetitions per set. A
novel ``Fatigue Resistance Index'' (FRI) was then calculated for each
individual subject for both CON and ECC contractions. The group CON FRI
(36.5 \pm 3.9% maximal force) was greater than group ECC FRI
(26.9 \pm 2.7% force). This protocol and FRI permit
comparisons between eccentric and concentric dynamic anaerobic muscle
performances for a given individual subject, or for a group of subjects.
