Venous hemodynamics in active and passive calf movements in healthy adults.

ObjectiveThe physiological effects produced by the calf pump are essential in multiple aspects of vascular health, and their absence leads to stasis which directly relates to venous insufficiency. Therefore, muscle activity has been considered a key element in calf pump function. In the present study, we used a mechanical foot board with passive range of motion including stimulated dorsiflexion and plantar flexion and compared the hemodynamic effects to those obtained during active voluntary movement.Methods11 healthy adult volunteers participated in an intervention study. In Intervention 1, the participants performed voluntary dorsiflexion and plantar flexion, and in Intervention 2, the same participants used the passive PumpCare^® device (OAK Healthtech, Brazil). Both legs were examined, but data were collected from the right leg. Femoral vein blood flow was assessed by ultrasound, and venous pump capacity (V₀) by photoplethysmography. Anthropometric data were collected to investigate their correlation with femoral vein blood volume.ResultsThe mean femoral vein blood flow was 286 mL/min with active calf movements and 288 mL/min with passive calf movements (p = .929). Flow peaks were produced during dorsiflexion, that is, during stretching of the posterior muscle groups, returning to baseline levels after stopping the movement in both interventions. The mean maximal venous pump capacity measured by photoplethysmography was 3.7% with active calf movements and 3.5% with passive calf movements (p = .141).ConclusionIn this study, passive calf movements were able to promote a mean femoral vein volume flow comparable to the physiological effect produced by active calf movements in healthy adults. This appears to contradict the current understanding of the importance of calf muscle contraction in producing venous return.