Altered contractile properties of the quadriceps muscle in people with spinal cord injury following functional electrical stimulated cycle training

Abstract

Study design: A longitudinal training study. Objectives: To assess if contractile speed and fatigability of paralysed quadriceps muscles in individuals with spinal cord injury (SCI) can be altered by functional electrical stimulation leg cycle ergometry (FES-LCE) training. Settings: The Sint Maartenskliniek rehabilitation centre and the University of Nijmegen, Nijmegen, the Netherlands. Methods: Contractile properties of the quadriceps muscle were studied in seven people with motor-complete SCI who participated in a FES-LCE training program. Subjects trained for 30 min, three times per week for 6 weeks. Contractile speed and fatigue characteristics of electrically stimulated isometric contractions were compared before and after 6 weeks of FES-LCE. Results: Fatigue resistance improved following FES-LCE training as indicated by the higher forces maintained in response to repetitive electrical stimulation. In contrast with an improved fatigue resistance, the maximal rate of force rise was unaected, the speed of relaxation increased and the fusion of a 10 Hz force signal decreased. Furthermore, the force-frequency relationship shifted to the right at low stimulation frequencies, indicated by a decline in the ratio of 1 and 100 Hz force responses as well as the ratio of 10 and 100 Hz force responses. Conclusion: FES-LCE training can change the physiological properties of the quadriceps muscle in people with SCI. Even after a short period of training, the stimulated muscles become more resistant to fatigue. Furthermore, the increased speed of relaxation and associated decreased fusion and altered force-frequency relationship following training may be related to adaptations in the calcium handling processes, which re¯ect an early response of long-term disused muscles. Spinal Cord (2000) 38, 214 ± 223

Effects of modified electrical stimulation-induced leg cycle ergometer training for individuals with spinal cord injury

“…Not only did the peak torques improve but also fatigue resistance improved considerably in all muscle groups, which is in agreement with other studies involving ankle or knee extension [36][37] or leg cycling exercise [38] induced by ES in individuals with SCI.…”

Abdominal functional electrical stimulation to improve respiratory function after spinal cord injury: a systematic review and meta-analysis

“…As the thickness and hence strength of the abdominal muscles has been shown to be reduced in SCI, 38 one explanation for the chronic increases in FVC and PEF reported here is that even for patients with complete paralysis of the abdominal muscles, Abdominal FES training thickens and strengthens the abdominal muscles, altering the passive biomedical properties of the respiratory system. 10 Such strengthening of muscles after FES training has been demonstrated through a shift in the force frequency curve, 39 increased muscle blood supply 40 and muscle fibre type conversion towards more fatigue resistant fibres. 40,41 McLachlan et al 10 propose that this strengthening of the abdominal muscles leads to greater support of the abdominal contents, which act as a fulcrum as the diaphragm contracts, placing the diaphragm in a more efficient mechanical position to expand the lower lung after Abdominal FES training.…”

“…10 Such strengthening of muscles after FES training has been demonstrated through a shift in the force frequency curve, 39 increased muscle blood supply 40 and muscle fibre type conversion towards more fatigue resistant fibres. 40,41 McLachlan et al 10 propose that this strengthening of the abdominal muscles leads to greater support of the abdominal contents, which act as a fulcrum as the diaphragm contracts, placing the diaphragm in a more efficient mechanical position to expand the lower lung after Abdominal FES training. There is also evidence in the literature to suggest that exercise contributes to an increase in brain-derived neurotrophic factor, which may promote synaptic and functional plasticity within the brain and spinal cord.…”

Kinematic analyses of semireclined leg cycling in able-bodied and spinal cord injured individuals

“…Stationary FES-induced semireclined leg cycling (FES-LCE) is used clinically as a form of therapeutic exercise to prevent secondary impairments following SCI injury. [1][2][3] Results from these studies indicate that FES-LCE: (1) increases muscle mass, [4][5][6] (2) improves strength and endurance, [7][8][9] (3) facilitates improvements in function, 7 (4) increases cardiovascular fitness, 7,8,10 (5) improves circulation, 7,8,11 (6) decreases swelling due to edema, 12 (7) reduces rate of bone density loss, 13,14 and (8) reduces lower limb blood pooling. 15,16 These results suggest that FES-induced muscle contraction during cycling exercise can be a valuable clinical rehabilitation tool for individuals with SCI in improving rehabilitation outcome, health, and fitness.…”