Effects of functional electric stimulation cycle ergometry training on lower limb musculature in acute sci individuals

Abstract

The purpose of this study was to compare three different intervals for a between sets rest period during a common isokinetic knee extension strength-testing protocol of twenty older Brazilian men (66.30 ± 3.92 yrs). The volunteers underwent unilateral knee extension (Biodex System 3) testing to determine their individual isokinetic peak torque at 60, 90, and 120° ·s-1. The contraction speeds and the rest periods between sets (30, 60 and 90 s) were randomly performed in three different days with a minimum rest period of 48 hours. Significant differences between and within sets were analyzed using a One Way Analysis of Variance (ANOVA) with repeated measures. Although, at angular velocity of 60°·s-1 produced a higher peak torque, there were no significant differences in peak torque among any of the rest periods. Likewise, there were no significant differences between mean peak torque among all resting periods (30, 60 and 90s) at angular velocities of 90 and 120°·s-1. The results showed that during a common isokinetic strength testing protocol a between set rest period of at least 30 s is sufficient for recovery before the next test set in older men. Key PointsMuscle fiber cross sectional area (CSAf ) decreased 38% following spinal cord injury (SCI).Early intervention with functional electric stimulation cycle ergometry (FES-CE) prevented further loss of CSAf in SCI patients and increased power output.Muscle myosin heavy chain (MHC) and myonuclear density were unaffected by SCI or FES-CE.

Keywords: Aging; isokinetic test; muscle fatigue; muscle strength.

Figure 1.

Cross sectional area (CSA) as seen with Hemotoxin and Eosin stain of initial biopsy uninjured control (top) and injured control (bottom) 5 weeks post injury.

Figure 2.

SDS-PAGE Myosin Heavy Chain (MHC). Representative picture of MHC gel.

Figure 3.

Effect pf FES-CE (Functional electric stimulation cycle ergometry) training on power output in acute SCI (spinal cord injured) patients. All values are mean ± SEM, n = 5. # denotes significant difference from weeks 1-4 (p < 0.05).

Figure 4.

Effect of SCI (spinal cord injury) and FES-CE (functional electric cycle ergometry) on CSAf (muscle fiber cross sectional area; μm²) pre-treatment (empty); vs. post-treatment (black). UIC; uninjured control, IC; injured control, IE; injured exercise trained. a = significantly different than UIC; b = significantly different than baseline in same group; c = significant difference between IC and IE. Level of significance was (p < 0.05).

Figure 5.

Effect of SCI (spinal cord injury) and FES-CE (Functional electric stimulation cycle ergometry) on myonuclear density (myonucle·mm^-2) pre-treatment (empty) vs. post treatment (black). All values are mean ± SEM, n = 5, IC-post n = 4. UIC; uninjured control, IC; injured control, IE; injured exercise trained.