Affiliations: [a] Center for Sport Performance, Department of Kinesiology, Human Performance Laboratory, California State University, Fullerton, CA, USA | [b] Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil | [c] San Francisco State University, San Francisco, CA, USA | [d] University of Kansas, Lawrence, KS, USA
Correspondence:
[*]
Corresponding author: Lee E. Brown, California State University, Fullerton, Department of Kinesiology, 800 N. State College Blvd, Fullerton, CA 92831, USA. Tel.: +1 657 278 4605; Fax: +1 657 278 1366; E-mail:leebrown@fullerton.edu
Abstract: BACKGROUND: Anaerobic fatigue is a limiting factor in performance
and athletes are often tested to determine their fatigue resistance.
Administering the classic Thorstensson test of fatigability is a popular
method to determine fatigue percentage as it requires 50 maximal knee
extension repetitions. However, there has been little research to determine
whether performing more or fewer repetitions yields similar results. OBJECTIVE: The purpose of this study was to compare concentric
fatigue percentage (FP) between the classic Thorstensson test (CT; average
of first 3 repetitions to average of last 3 repetitions) and three different
repetition ranges: peak torque repetition to repetition 30 (P30), peak
torque repetition to repetition 50 (P50), and peak torque repetition to
repetition 60 (P60). METHODS: Fifteen resistance trained men (age = 24.8 ± 1.3 yrs;
height = 178.9 ± 5.1 cm; mass = 82.2 ± 8.0 kg) volunteered to perform 60
maximal concentric knee extension repetitions at 180°/s on an isokinetic
dynamometer, measuring peak torque of each repetition. RESULTS: P30 (r= 0.81) and P50 (r= 0.77) were highly correlated with CT
but P60 (r= 0.58) was only moderately correlated with CT. P30 FP (44.7 ± 8.8) was significantly less than CT (62.3 ± 6.0), P50 (66.0 ± 6.8)
and P60 (69.7 ± 7.1). CONCLUSION: FP can be determined through fewer repetitions of a
knee extension fatigue test on an isokinetic dynamometer. While both P30 and
P50 were highly correlated with CT, performing fewer repetitions requires
less time to complete as well as less residual fatigue. When measuring knee
extension FP, the number of repetitions performed in the test may be reduced
to 30 while still maintaining a high correlation to a longer method of 50.
