Kinematical and Muscular Fatigue in Swimmers

During a submaximal task, gradual muscle fatigue occurs, which inevitably results in a decline in performance (mechanical failure). Elite athletes are known to employ unconscious compensatory strategies during fatiguing submaximal tasks in an attempt to delay the onset of mechanical failure as long as possible. The purpose of this study was to gain valuable insight into the strategies used by elite swimmers to cope with mechanical failure. Twenty-two swimmers were subjected to a swim test consisting of swimming as long as possible at a predetermined and controlled pace. A light strip positioned at the bottom of the pool allows athletes to get feedback on which gait to keep. The kinematics (stroke rate, stroke length, and efficiency index) and electrical activity of 10 muscle groups were analyzed and compared at the beginning of the test (non-fatiguing conditions), just before the athlete lost the ability to maintain the predetermined pace (pre-mechanical failure), and after the athlete lost the ability to maintain the pace (mechanical failure). It is hypothesized that as fatigue becomes more pronounced and the point of inability to maintain a predetermined speed is approached, increased EMG activity will occur in key muscles while other muscle groups may show more obvious signs of fatigue. In addition, changes in the rhythm and coordination of upper limb movements may occur.