Thursday Morning Poster Presentations: Posters displayed from 7:30 a.m.–12:30 p.m.: One-hour author presentation times are staggered from 8:30–9:30 a.m. and 9:30–10:30 a.m.: C-35 Free Communication/Poster – Psychological and Neurological Factors in Fatigue THURSDAY, JUNE 1, 2006 8:30 AM – 10:30 AM ROOM: Hall B
The theory of teleoanticipation proposes that muscle power output is modified by a “central governor” that takes into account projected “finishing points” and afferent feedback from the muscle. It has been suggested that this allows the selection of an optimum pacing strategy that will allow completion of the task in the most efficient way while maintaining internal homeostasis and a metabolic and physiological reserve capacity. While teleoanticipation has been proposed to occur during all forms of exercise, it has not previously been investigated during repeated-sprint exercise.
PURPOSE: The present study investigated the effects of varying the anticipated number of all-out sprints on repeated-sprint performance.
METHODS: Six young men and women completed two trials of two sets of 3, 4-s cycling sprints (separated by 20-s passive recovery intervals), in a random order. In one trial, subjects were deceived and told that they would be performing two sets of 6, 4-s cycling sprints. In the second trial, there was no deception. Between each set of 3 sprints, subjects rested passively for 180 s. The EMG activity from the vastus lateralis, vastus medialis, rectus femoris and biceps femoris of the right leg was recorded via bipolar surface electrodes, and a MVC was performed on a specially manufactured cycle ergometer pre and immediately post exercise.
RESULTS: There was no significant difference in total work performed between the two conditions in either the first (142.8 ± 22.5 vs 141.4 ±19.8 J/kg) or second set (138.6 ± 19.5 vs 139.5 ± 19.5 J/kg). Similarly, there was no significant difference in work decrement across the 3 sprints between the two conditions in either the first (4.2 ±2.5 vs 5.1 ±2.6 %) or second set (5.7 ±3.4 vs 5.5 ± 1.5 %). There was a parallel fall in muscle power output and IEMG activity during both conditions with no significant difference between conditions.
CONCLUSIONS: The parallel fall in muscle power output and IEMG activity suggest that fatigue during maximal, repeated-sprint exercise is associated with centrally-mediated changes. However, this fatigue was not influenced by perception of the end point of the exercise bout.