Volitional Muscle Strength in the Legs Predicts Changes in Walking Speed Following Locomotor Training in People With Chronic Spinal Cord Injury
By Yang, Jaynie F.; Norton, Jonathan; Nevett-Duchcherer, Jennifer; Roy, Francois D.; Gross, Douglas P.; Gorassini, Monica A.; Physical Therapy (PTJ) , Volume 91, Number 6, pages 931-943Publication Date: June 2011
Study was undertaken to determine the factors that predict whether a person with motor-incomplete spinal cord injury (SCI) will respond to body-weight supported treadmill training. Participants were 19 individuals with chronic motor-incomplete SCI aged 20 77 years, 5 of whom were women. Demographic, clinical, and electrophysiological measurements taken prior to a mean 18 weeks of training were examined to determine which measures best predicted improvements in walking speed. Two initial measures correlated significantly with improvements in walking speed: (1) the ability to volitionally contract a muscle, as measured by the lower extremity manual muscle test (LE MMT), and (2) the peak locomotor electromyographic (EMG) amplitude in the legs. None of the demographics, such as time since injury, age, and body mass index, were significantly related to improvements in walking speed, nor was the clinical measure of balance as determined by the Berg Balance Scale. Further analysis of LE MMT scores showed 4 key muscle groups were significantly related to improvements in walking speed: knee extensors, knee flexors, ankle plantar flexors, and hip abductors. Prediction using the summed MMT scores from those muscles and peak EMG amplitude in a multivariable regression indicated that peak locomotor EMG amplitude did not add significantly to the prediction provided by the LE MMT alone. Change in total LE MMT scores from the beginning to the end of training was not correlated with a change in walking speed over the same period. Study limitations and clinical implications are discussed.
Published by: American Physical Therapy Association (Website:http://www.apta.org)
Link to text: http://ptjournal.apta.org/content/91/6/931.long
