Issn Print: 0195-9131
Publication Date: 1997/05/01
INFLUENCE OF SACCHAROSE SUPPLEMENTATION ON NEUROMUSCULAR EXCITABILITY (NME) DURING PROLONGED HEAVY EXERCISE 112
G. Schiestl; U. Gastmann; J. M. Steinacker; M. Lehmann
Excerpt
The hypothesis was tested, that a deterioration in NME is prevented during prolonged heavy exercise by carbohydrate supplementation, since NME of stressed muscles deteriorates during prolonged heavy exercise and high-volume and high-intensity overtraining. As marker of skeletal muscles' NME, the minimal rectangular current pulse was used, that produces a single contraction of muscle fibers at different pulse durations. 6 cyclists (24.8 ± 3.9 ys, 392 ± 38 Watts maximum power output) participated in a double-blind, randomized, controlled study. Prolonged exercise consisted of 2 hours cycling, first hour at 75% of 4 mmol lactate performance (4LT), second at 65% of 4LT, followed by a standardized 30 min break and a final ramp test to discriminate degree of exhaustion. Saccharose was supplemented (15 g in 0.3 L water; saccharose test) or not (only water; control test) at baseline, and after 30, 60, and 90 mins. Ramp test performance was significantly higher in the saccharose test 388 ± 34 Watts) compared to control test (342± 0 Watts). As expected, NME of vastus medialis muscle deteriorated in the control test. Deterioration was completely prevented in the saccharose test. These results indicate that deterioration in NME during prolonged heavy exercise may be related may be related to a deterioration in energy flux rate dependent on decrease in glycogen supplies.
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