The purpose of this study was to determine the effects of fatigue on motor performance and learning of a gross motor task. Thirty-two college men (20.1 +/- 1.9 years) practiced a task involving repetitive displacement of body weight over a four-week period. The task required hopping on one or both feet to a sequence of 32 footprints painted on a patterned board. Correct placement of the feet on the footprints was the response score used to assess performance and learning. Subjects were randomly assigned either to a group (F-P) that was fatigued before practice or to a control group (C). Fatigue levels were leg strength decrements of 20 percent or 40 percent of maximum strength. A maximum number of repetitions was performed with loads of 80 percent or 60 percent of maximum strength to achieve, respectively, a 20 percent or 40 percent strength decrement on the last repetition. Subjects in Group C were divided into two subgroups (n = 8), with one experiencing fatigue (30 percent strength decrement) immediately after practice. Comparisons between the two subgroups after four weeks disclosed significant differences (p < 0.05) in leg strength favoring the fatigued subgroup but no difference in performance or learning. Leg strength was not considered a learning variable. No significant differences were found in performance or learning between subjects in Group F-P who were fatigued to 20 percent or 40 percent strength decrement. Subgroup comparisons in Group C verifying that strength was not a learning variable and in Group F-P that 20 percent and 40 percent strength decrements did not have differential effects supported the use of a 2 by 5 ANOVA to analyze test scores recorded under nonfatigued trials. Significant differences were found between Groups F-P (mean = 8.90) and C (mean = 10.95) (p < 0.05), and among the five testing sessions in performance and learning. Fatigue was considered a performance and learning variable.
(C) 1991 National Strength and Conditioning Association