Evaluation of skeletal muscle endurance and muscle oxidative capactiy using electrical twitch mechanomyography and near infrared spectroscopy

A skeletal muscle endurance test has been developed for use in clinical populations. PURPOSE: This study will evaluate two methods of generating an endurance index (EI) and compare these methods to mitochondrial capacity in skeletal muscle. METHODS: Healthy participants (n=15) were tested on two occasions. Surface electrodes and a tri-axial accelerometer were placed over the hamstring muscles. The stimulation induced skeletal muscle contractions (5Hz for 5 minutes). Maintenance of contraction acceleration was used to calculate an EI. Two analysis methods were used: peak-to-peak (P2P) and total (TLT). Each index was compared to mitochondrial capacity values measured by Near-Infrared Spectroscopy (NIRS). RESULTS: The P2P results were more reproducible (R2=0.87 vs R2=0.76) and had a stronger correlation with mitochondrial capacity (R2 =0.96 vs R2=0.36) than TLT (p < 0.05). CONCLUSIONS: The P2P analysis provided a reproducible measure of muscle endurance, which was consistent with mitochondrial capacity values.