The Influence of Functional Electrical Stimulation during Cycling Exercise on Cardiorespiratoric Response in Order of Cadence at Increasing and Persistent Exercise in Healthy Adults

Functional electrical stimulation is been used for about 50 years in treatment and rehabilitation of patients with stroke and spinal cord injury. Numerous studies could show positive effects of functional electrical stimulation (FES) combined with cycling movement (FES Cycling) [1,2]. Main improvements in stroke patients are motor changes, such as improving walking ability, balance and spasticity [3-5]. Increase of residual muscle strength, prevention of contractures and sense of well-being are described as important therapeutic goals in paraplegia [6,7]. Improvement of cardiorespiratory performance seems to be a considerable component for maintaining health [8], especially in patients with spinal cord injury. FES Cycling exercises interventions show significant improvements in cardiorespiratory parameters [9,10]. Investigations with simple electromyostimulation(EMS) without functional movement on cardiac patients with very low cardiac levels also show an increase in cardiorespiratory capacity [2,11]. The relationship between stimulation parameters, functional movement and effects on cardiorespiratory parameters is not yet sufficiently studied. In numerous investigations exercise protocols, stimulation frequencies and strength of electric current varies widely. It is known that rectangular pulses for FES are suitable [12,13]. Basically in both, healthy and paralyzed muscles with increased amperage, more motor units are recruited [14]. While different muscle activation patterns during FES Cycling may increase the cardiorespiratory load, the influence of different cycling cadences is discussed controversial [15,16]. The aim of this study was to investigate the acute effect of functional electrical stimulation and different cadences on cardiorespiratoric responses in passive cycling movement in healthy volunteers.