Neuromuscular electrical stimulation attenuates thigh skeletal muscles atrophy but not trunk muscles after spinal cord injury

Abstract

The current study examined the effects of 12weeks of surface neuromuscular electrical stimulation (NMES) and ankle weights on the cross-sectional areas (CSAs) of three thigh [Gracilis (Gra), Sartorious (Sar) and Adductor (Add)] as well as two trunk [hip flexor (HF) and back extensor (BE)] muscle groups in men with spinal cord injury (SCI). Seven individuals with chronic motor complete SCI were randomly assigned into a resistance training +diet (RT+diet; n=4) or diet control (n=3) groups. The RT+diet group underwent twice weekly training with surface NMES and ankle weights for 12weeks. Training composed of four sets of 10 repetitions of leg extension exercise while sitting in their wheelchairs. Both groups were asked to monitor their dietary intake. Magnetic resonance images were captured before and after 12weeks of interventions. Gra muscle CSA showed no change before and after interventions. A significant interaction (P=0.001) was noted between both groups as result of 9% increase and 10% decrease in the Gra muscle CSA of the RT+diet and diet groups, respectively. Sar muscle CSA increased [1.7±0.4-2.5±0.5cm(2); P=0.029] in the RT+diet group with no change [2.9±1.4-2.6±1.3cm(2)] in the diet group; with interaction noted between both groups (P=0.002). Analysis of covariance indicated that Add muscle CSA was 38% greater in the RT+diet compared to the diet group (P=0.025) after 12weeks; a trend of interaction was also noted between both groups (P=0.06). HF and BE muscle groups showed no apparent changes in CSA in both groups. The results suggested that surface NMES can delay the process of progressive skeletal muscle atrophy after chronic SCI. However, the effects are localized to the trained thigh muscles and do not extend to the proximal trunk muscles.