Musculoskeletal responses of spinal cord injured individuals to functional neuromuscular stimulation-induced knee extension exercise training

Abstract

Abstract-This study was conducted to evaluate a newly designed functional neuromuscular stimulation (FNS)-induced knee extension (KE) exercise system that incorporates the most desired features of previously described systems by determining the musculoskeletal responses of spinal cord injured (SCI) individ~tals to training. A specially designed chair and electrical stimulator were fabricated for FNS-induced KE resistance exercise. Surface electrodes were placed over motor points of the quadriceps muscles, and KE was alternated between legs at an average rate of 6 KEJminIleg. KE testing protocols were developed for pre-and post-training evaluations of performance, and 12 SCI subjects exercise-trained up to three times per week for 36 sessions using a progressive resistance load at ankle level. Pre-and post-training evaluation data were statistically compared using a 0.05 level for significance. Quadriceps muscle pellformance (strength X repetitions) improved for both legs in all subjects as indicated by significant increases in load resistance and repetitions over the 36-session training period (right leg %= 1156.0 versus 1624.8 kg.reps, left leg %= 1127.3 versus 1721.1 kgereps). In addition, knee range of motion significantly increased (right leg %= 134 versus 146 degrees, left leg ?= 133 versus 144 degrees). Thigh skinfold, thigh girth, body weight and bone density were not significantly changed. The lack of decrease in bone density in some subjects suggests that the training may retard the rate of bone loss which typically occurs with SCI. No injuries or problems were encountered during testing and training. Therefore, this newly-designed FNS-KE exercise appears to be safe, easy to use, and effective for all subjects who participated in the study. The protocol developed for this form of FNS training of the quadriceps may be used to increase the integrity of muscles paralyzed due to SCI. In addition, the enhanced muscle petfomnce reserve may better enable the SCI individual to accomplish more complex FNS tasks with less fatigue.

Does Standing Protect Bone Density in Patients With Chronic Spinal Cord Injury?

“…Studies with functional electric stimulation reported conflicting results. Mohr et al (14), Hangartner et al (15), and Bloomfield et al (16) reported significant increases in BMD with functional electric stimulation, whereas other studies found no significant BMD changes (4,(17)(18)(19). Shields et al (4) demonstrated that compressive loads of 1 to 2 times body weight induced by muscle contractions partially prevented the loss of BMD after SCI.…”

Long-term exercise training in persons with spinal cord injury: effects on strength, arm ergometry performance and psychological well-being

“…Unfortunately, the vast majority of longitudinal studies have been relatively short in duration (524 weeks), restricted to either persons with paraplegia or persons with tetraplegia, and have been rather narrow in their focus on outcome measures. For example, studies have examined the e ects of exercise training on either cardiorespiratory function 7,9 or muscle strength, 12,13 but relatively few have included both strength and cardiovascular endurance measures in their outcomes, and fewer still have included measures of quality of life (QOL). One study, more than two decades ago, attempted to include multiple outcome measures, 14 and they reported signi®cant improvements in exercise capacity (31%), maximum oxygen uptake (12%), and strength (19%) after 7 weeks of thrice-weekly training in persons with incomplete paraplegia.…”

Is body weight-support treadmill training effective in increasing muscle trophism after traumatic spinal cord injury? A systematic review

“…[24][25][26] Over the last few decades, activity-based therapy using body weight-support treadmill training (BWSTT) has shown beneficial effects in the motor function recovery of SCI patients and has been widely used. 5,6,[26][27][28][29] BWSTT involves the practice of stepping on a motorized treadmill while the individual remains stabilized by a belt connected to a counterweight system that regulates the unloading percentage of body weight on the lower limbs during the stance phase of gait.…”