Changes in Lower Extremity Strength May be Related to the Walking Speed Improvements in Children with Cerebral Palsy After Gait.
Copious amounts of research have demonstrated that gait training can improve the ability of children with spastic cerebral palsy to ambulate. The purpose of this study was to determine if lower extremity strength increases secondary to gait training is the primary physiological cause of said increased ability to ambulate. Determining if lower extremity strength increases is the primary physiological cause would allow clinicians to supplement their gait training program with a focused lower extremity strengthening program when working with children with a diagnosis of spastic cerebral palsy.
Children both male and female who have a diagnosis of cerebral palsy (either hemiplegic or diplegic). Ages of participants ranged from 6-17 and were a 2 or 3 on the gross motor function classification system.
The participants were recruited from the routinely seen patient population at the Munroe-Meyer Institute for physical therapy and gait analysis. All participants underwent a series of pre and post treatment testing surrounding a six-week gait training program.
Diagnosis of spastic cerebral palsy, level 2 or 3 on the gross motor function classification system, able to walk independently with or without an assistive device.
Orthopedic surgery or botox injections within the last 6 months.
Each participant received gait training three times a week for six weeks with at least one day of rest between training. Participants were able to use any prescribed assistive devices and ambulated on a treadmill using a body weight support system. Amount of body weight support and speed of the treadmill was adjusted inter session and intra session. Amount of support and speed of treadmill decisions were made by a licensed pediatric physical therapist. With intent of challenging the participant minimal body weight support with the patient able to maintain as much upright posture as possible was used. Similarly, the fastest treadmill speed with the participant able to maintain posture and gait mechanics was implemented.
The outcome measures used during the pre and post treatment assessments included: six-minute walk test, fast-as-possible 10m walking speed, and a strength testing of lower extremity anti-gravity musculature using a hand-held dynamometer.
After six weeks of gait training children with spastic cerebral palsy demonstrated a statistically significant increase in fast-as-possible gait speed as well as a statistically significant increase in distance on the six-minute walk test. The participants also showed a statistically significant increase in their composite lower extremity strength scores. A positive coefficient of determination showed that change in lower extremity strength justified 83% of the difference in 10m walking speed. Finally, this article also demonstrated a negative coefficient of determination between age and lower extremity strength indicating that the younger the child the higher the chance of increasing lower extremity strength.
Overall this was a very well-orchestrated study with impressive outcomes and clinically significant findings. I believe one of the largest strengths of this article is the wide population and inclusion into the study. Due to the authors including both male and female children from 6-17 and with both hemiplegic and diplegic cerebral palsy the results have wide spread implications, opposed to using a more specific patient population.
The main limitation to this study is the small sample size. The authors began with 11 participants however were only able to use 10 sets of data due to one participant being unable to perform the complete battery of test. Despite the small sample size, they did have a strong effect size for walking endurance; however, they had a small to medium effect size for both lower extremity strength gains and walking speed.
This study was very well performed and presents clinically important findings. This article adds to the existent literature that gait training increased ambulation ability in children with cerebral palsy. This article also demonstrates a strong correlation between increased lower extremity strength and gait speed and endurance. This article indicates that physical therapist working with this population should consider including a lower extremity strengthening program in conjunction with their gait training program.
Rashelle M. Hoffman, Bradley B. Corr, Wayne A. Stuberg, David J. Arpin, Max J. Kurz,
Changes in lower extremity strength may be related to the walking speed improvements in children with cerebral palsy after gait training. Research in Developmental Disabilities. 2018; 73: 14-20. ISSN 0891-4222. https://doi.org/10.1016/j.ridd.2017.12.005.