Cycling device powered by the electrically stimulated muscles of paraplegics

Abstract

The paper describes a device (Paracycle), that uses functional neuromuscular stimulation to exercise subjects, explore FNS technology and provide paraplegics with locomotion. The Paracycle is a four-wheeled cycling vehicle that may be used as a stationary exercise device or for locomotion. It incorporates a fully adjustable seat and an electric motor to assist or retard the cycling motion, as well as speed and direction controls. Furthermore, it has braces to fasten the feet to the pedals and to stabilise the ankle, as well as gearing to enable subjects with very small forces to move the vehicle forward. Results are presented for two cases studies. Good stability of the leg was achieved during the cycling motion and this would appear to be a major advantage of functional neuromuscular stimulation cycling over functional neuromuscular stimulation gait. Important areas for future research include a better understanding of the biomechanics of functional neuromuscular stimulation cycling and the development of Paracycle-like devices that can be used independently by paraplegics.

Comparison of stimulation patterns for FES-cycling using measures of oxygen cost and stimulation cost

“…While most previous studies have utilised stationary FES-cycling ergometers, a number of mobile devices have also been proposed [5,6,7,8,9], raising the possibility that FES-cycling might become a recreational activity.…”

“…Previous studies have analysed electromyographic (EMG) data from normal subjects during volitional cycling to identify muscle timing characteristics [17,18,19,6,20], and have attempted to use the results to design activation ranges for SCI subjects performing FES-cycling on the same ergometer device. Two of these studies, [6,20], found that the activation patterns obtained during normal, volitional cycling had to be manually adjusted in order to achieve smooth cycling motion with paraplegic subjects. Petrofsky's studies [17,18,19] each reported measurement of EMG activation patterns from four normal subjects, and the apparently successful use of these to set the timing and stimulation intensity variables for paraplegic cycling.…”

Control strategies for integration of electric motor assist and functional electrical stimulation in paraplegic cycling: utility for exercise testing and mobile cycling

“…Unfortunately, very little data reporting testing of these mobile devices with paraplegic subjects, or usage outside of laboratory conditions, have been published, and it is, therefore, difficult to assess their utility. We note that the systems described by Pons et al [3] and Gföhler et al [4] both included an auxiliary electric motor. In both cases, the motor is manually controlled in a feedforward manner.…”

“…Several groups have described mobile FES cycles [1], [3], [4], [13]. Unfortunately, very little data reporting testing of these mobile devices with paraplegic subjects, or usage outside of laboratory conditions, have been published, and it is, therefore, difficult to assess their utility.…”

“…The throttle can be used by the cyclist in a number of ways, depending on the control software configuration: it can be used to directly control the motor input signal; it can alternatively be used in FES cycling to directly vary the stimulation intensity; or in closed-loop control configurations it can be used to set the reference values for the controlled variables (e.g., desired cadence or leg power). The right crank of the tricycle is replaced by a torque measurement sensor 3 [resolution 2.5%, see Fig. 2(b)].…”