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.