Electrically stimulated resistance training in SCI individuals increases muscle fatigue resistance but not femoral artery size or blood flow

Abstract

Study design: Longitudinal. Objectives: The purpose of this study was to evaluate the effect of lower extremity resistance training on quadriceps fatigability, femoral artery diameter, and femoral artery blood flow. Setting: Academic Institution. Methods: Five male chronic spinal cord injury (SCI) individuals (American Spinal Injury Association (ASIA): A complete; C5-T10; 3675 years old) completed 18 weeks of home-based neuromuscular electrical stimulation (NMES) resistance training. Subjects trained the quadriceps muscle group twice a week with four sets of 10 dynamic knee extensions against resistance while in a seated position. All measurements were made before training and after 8, 12, and 18 weeks of training. Ultrasound was used to measure femoral artery diameter and blood flow. Blood flow was measured before and after 5 and 10 min of distal cuff occlusion, and during a 4-min isometric electrical stimulation fatigue protocol. Results: Training resulted in significant increases in weight lifted and muscle mass, as well as a 60% reduction in muscle fatigue (P ¼ 0.001). However, femoral arterial diameter did not increase. The range was 0.4470.03 to 0.4670.05 cm over the four time points (P ¼ 0.70). Resting, reactive hyperemic, and exercise blood flow did not appear to change with training. Conclusion: NMES resistance training improved muscle size and fatigue despite an absence of response in the supplying vasculature. These results suggest that the decreases in arterial caliber and blood flow seen with SCI are not tightly linked to muscle mass and fatigue resistance. In addition, muscle fatigue in SCI patients can be improved without increases in arterial diameter or blood flow capacity.

Electrical stimulation-evoked resistance exercise therapy improves arterial health after chronic spinal cord injury

“…The final model adjusts for weekly differences in arterial constriction % (AC%) did not find any evidence that blood velocity was altered as a result of training. 24 Furthermore, in our previous studies, we found no evidence that hyperemic blood velocity after cuff ischemia was reduced in patients with SCI versus non-disabled controls. 41,42 We do agree that future studies would benefit from measurement of blood velocity and calculation of shear rates.…”

A systematic review of exercise as a therapeutic intervention to improve arterial function in persons living with spinal cord injury

“…51 With such limited data, it is difficult to interpret the value of this exercise technique. More research needs to be completed investigating [64][65][66][67][68] the acute vascular changes in response to stretch-induced contractions.…”

“…In the first study, improved quadriceps strength was found, but no improvements in femoral arterial structure or function (artery diameter, hyperemic response, exercise blood flow response). 68 In the follow-up study from the same group, improved femoral artery flow-mediated dilatation was elevated after the training regimen. 67 Another study performed by Taylor et al, 24 which used a progressive 3-month long knee extension exercise with the aim of allowing standing, illustrated increased muscle thickness and thigh blood flow.…”

“…Two articles were case-control studies, 69,70 11 were of the pre-post design, 24,71-75 one was a case report and one was an RCT. The Non-Acute Exercise category (n ¼ 15) included passive leg exercise (n ¼ 1), 49 FES (n ¼ 5), 65,[70][71][72][73] upper body exercise (n ¼ 2), 69,76 an electrically stimulated resistance training regimen (n ¼ 3), 24,67,68 hybrid exercise (n ¼ 3) 66,74,75 and BWSTT (n ¼ 1). 64 Table 3 is a summary of published investigations examining the effect of non-acute exercise on arterial function in those with SCI.…”

“…Electrically stimulated knee extension, which involves electrical stimulation of the denervated musculature to increase strength, has been investigated by three studies as a potential technique for De Groot et al 72 The improving arterial structure and function in those with SCI. 24,67,68 Two studies' training regimen consisted of exercise 2 days per week, for 8 weeks. In the first study, improved quadriceps strength was found, but no improvements in femoral arterial structure or function (artery diameter, hyperemic response, exercise blood flow response).…”