Resistance training and locomotor recovery after incomplete spinal cord injury: A case series

Study design: Longitudinal intervention case series. Objective: To determine if a 12-week resistance and plyometric training program results in improved muscle function and locomotor speed after incomplete spinal cord injury (SCI). Setting: University research setting. Methods: Three ambulatory individuals with chronic (18.7±2.2 months post injury) motor incomplete SCI completed 12 weeks of lower extremity resistance training combined with plyometric training (RPT). Muscle maximum cross-sectional area (max-CSA) of the knee extensor (KE) and plantar flexor (PF) muscle groups was determined using magnetic resonance imaging (MRI). In addition, peak isometric torque, time to peak torque (T_20-80), torque developed within the initial 220 ms of contraction (torque₂₂₀) and average rate of torque development (ARTD) were calculated as indices of muscle function. Maximal as well as self-selected gait speeds were determined pre- and post-RPT during which the spatio-temporal characteristics, kinematics and kinetics of gait were measured. Results: RPT resulted in improved peak torque production in the KE (28.9±4.4%) and PF (35.0±9.1%) muscle groups, as well as a decrease in T_20-80, an increased torque₂₂₀ and an increase ARTD in both muscle groups. In addition, an increase in self-selected (pre-RPT=0.77 m/s; post-RPT=1.03 m/s) and maximum (pre-RPT=1.08 m/s; post-RPT=1.47 m/s) gait speed was realized. Increased gait speeds were accompanied by bilateral increases in propulsion and hip excursion as well as increased lower extremity joint powers. Conclusions: The combination of lower extremity RPT can attenuate existing neuromuscular impairments and improve gait speed in persons after incomplete SCI.