Neuromuscular and anaerobic performance of sprinters at maximal and supramaximal speed.

Neuromuscular and anaerobic performance was investigated in nine male sprinters who were running at maximal and supramaximal speeds. Supramaximal running was performed by a towing system. A rubber rope pulled by an electronic motor towed the runner, and the angle of draught ranged from 10 degrees to 17 degrees upward from the horizontal. All runs were filmed at 100 frames X s-1, and ground reaction forces were measured with a long force platform system. EMGs were recorded telemetrically with surface electrodes from five leg muscles. Blood lactate and oxygen debt were measured during recovery. The results indicated that in supramaximal running the increases in velocity (4.3%-4.6%) were associated with increase in stride length (P less than 0.01). Comparison of the ground reaction forces showed that in the impact phase maximal force, average force, work, and power were significantly (P less than 0.01-0.001) greater in a horizontal direction and maximal and average forces were greater (P less than 0.05-0.01) in a vertical direction compared with a preceding maximal run. There were no significant differences in EMG activity of any studied muscle between the various runs. Peak blood lactate was 27.7% (P less than 0.001) and oxygen debt 30.3% (P less than 0.01) higher after maximal than supramaximal runs. It is concluded that supramaximal running with towing horizontally and vertically simultaneously causes increases in stride length and changes are associated with a smaller energy expenditure despite the high intensity of the performance.