Exposure of the legs to a supra-atmospheric pressure of 50 mmHg (Leg Positive Pressure) reduced exercise performance by 40% during supine cycle ergometry compared to the control condition.
Does experimental restriction of blood flow in working muscles affect dynamic exercise performance and cardiovascular/respiratory functions in humans?
Experimental restriction of blood flow during exercise reduces performance and augments pressor and ventilatory responses, likely due to increased activation of muscle chemoreflexes.
Effect estimate: 40% reduction
The effects of reduced muscle perfusion pressure on dynamic exercise performance and cardiovascular and respiratory functions were investigated. Eight subjects were studied during supine cycle ergometry at stepwise increasing workloads until exhaustion with and without the legs exposed to a supra-atmospheric pressure of 50 mmHg (Leg Positive Pressure, LPP), a novel and convenient means of reducing the perfusion pressure in the working muscles. In the LPP condition exercise performance was reduced by 40% which, judging from assessments of perceived exertion, was due to premature muscle fatigue, indicating local or overall underperfusion of the working muscles. At any given work load, the arterial pressure response was considerably stronger during LPP than in the control condition. LPP also caused greater increases in blood lactate concentration and pulmonary ventilation, the differences from control increasing with the work load. Furthermore, the ventilatory equivalent for O2 at a given work load was markedly higher in the LPP than in the control condition, while exercise-induced decreases in end-tidal PCO2 were considerably exaggerated by LPP. The augmented pressor response during flow-restricted exercise, together with the strong ventilatory response which was out of proportion to overall O2 uptake, suggests increased activation of muscle chemoreflexes by accumulation of metabolic end products, the increased pressor response tending to reduce the local flow error in the working muscles.
Eiken et al. (Sun,) reported a other. Leg Positive Pressure (LPP) vs. Without LPP (control condition) was evaluated on Exercise performance (40% reduction). Exposure of the legs to a supra-atmospheric pressure of 50 mmHg (Leg Positive Pressure) reduced exercise performance by 40% during supine cycle ergometry compared to the control condition.