Abstract des Autors

The influence of graded leg muscle ischaemia on the adaptation to training and on the acute response to exercise was studied in healthy subjects. Graded ischaemia during supine exercise was induced by application of 50 mmHg external pressure on the legs that reduced leg blood flow 13-20%. One-legged training was performed during four weeks, 4 sessions per week. Each session started with one leg training for 45 min with reduced blood flow (ischaemic training). The contralateral leg, serving as a control, was then trained with an identical power output profile for 45 min but without flow restriction (non-ischaemic training). Ischaemic training enhanced the adaptation to training. Peak oxygen and time to fatigue increased more with ischaemic than with non-ischaemic training. The number of capillaries per fiber and glycogen content were higher, the citrate synthetase activity was higher, the phosphofructokinase activity tended to be higher and total activity of lactate dehydrogenase tended to be lower in the I-leg than in the N-leg after the training. In the trained situation the percentage of type I fibres was higher in the I-leg than in the N-leg while the type IIB percentage was lower in the I-leg. During acute ischaemic exercise, as compared to non-ischaemic exercise, there was a higher degree of glycogen depletion and a greater depletion of type II but not of type I fibres. In conclusion, the mechanisms underlying the potentiation of the adaptation to training by ischaemia are assumed to depend on the operation of stimuli which were amplified during acute ischaemic exercise. Verf.-Referat