The relative effectiveness of three forms of visual knowledge of results on maximal strength output in an isokinetic extension/flexion of the knee

Graduation date: 1990This experiment was conducted to study the effects of three different\ud forms of visual knowledge of results (KR) on maximal strength output in\ud isokinetic exercise. The task used was an isokinetic extension of the knee,\ud followed by a corresponding flexion. Four, six-subject experimental groups\ud completed four testing sessions conducted over a five-day period. Group one\ud represented a no-KR control condition. Group two was provided with visual KR\ud in the form of a continuous torque-output display during treatment sessions.\ud Groups three and four were provided with concurrent and summary torque-time\ud graphs as visual KR, respectively. A pre-test was completed during the first\ud experimental session. Two consecutive testing sessions followed the\ud pre-testing session. After a one-day retention interval, a post-test and a\ud retention test comprised the final session.\ud The dependent measure of maximum peak torque (MPT) was collected\ud at each of two exercise speeds. Pre- and post-test MPT scores were analyzed\ud using a 2 X 4 (pre-/post- X group) analysis of variance (ANOVA) for each\ud exercise speed and movement direction. Day-to-day effects were evaluated\ud using 3 X 4 (day 1 / day 2 / retention day X group) ANOVAs. Group means for\ud factors yielding significant F-scores were compared using Tukey's WSD\ud post-hoc comparisons procedure.\ud The experimental findings indicated that post-test scores increased for all\ud groups, in both movement directions, when compared to pre-test scores.\ud Results also revealed that although the no-KR control group exerted\ud significantly higher mean MPT output during treatment and retention sessions,\ud visual KR presented concurrent with performance led to significant increases in\ud mean MPT output when compared to visual KR presented according to a\ud summary schedule.\ud Four major conclusions resulted from the experimental findings. First,\ud maximal strength output may be achieved in the absence of visual KR. Second,\ud more precise information (such as provided by a concurrent torque-time graph)\ud becomes more effective at low exercise speeds when sufficient time for\ud information processing is available subsequent to the presentation of visual KR.\ud Third, visual KR presented concurrent with performance is a more effective\ud performance and learning variable in isokinetic exercise when compared to\ud visual KR presented according to a summary schedule. Last, visual KR may\ud provide a reference of performance which serves as a limiting criterion in a\ud maximal-effort task