Power Training Combined With Interval Treadmill Training (PT³)

Power Training Combined With Interval Treadmill Training to Improve Walking Activity in Cerebral Palsy (PT³)

Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), University of Washington

Ambulatory children with cerebral palsy (CP) experience walking limitations which negatively influence their ability to physically participate in day to day life. The investigators propose that impaired muscle power generation is the key limiting factor affecting walking activity and participation. This proposal represents a combined approach where participants undergo resistance training for muscle power generation in combination with locomotor treadmill training that is based on typical pediatric walking and activity patterns rather than adult protocols, which are endurance or time-based. Therefore, the primary objective of this randomized controlled trial is to determine the effect of lower extremity Power Training combined with interval Treadmill Training (PT³) on functional walking capacity and community-based activity and participation in children with CP. We hypothesize that remediating the most pronounced muscle performance impairment (i.e., muscle power) with power training combined with a task- specific approach to walking that is developmentally appropriate will have a significant effect on walking capacity and performance.

The primary purpose of this randomized controlled trial is to test the effect of Power Training combined with interval Treadmill Training (PT³) on walking capacity and performance in children with CP with walking limitations. To identify key muscular mechanisms associated with improved walking mobility, the effects of PT³ on muscle performance and architecture will be examined. The premise of the PT³ protocol is that a combined impairment and task-specific approach that is developmentally appropriate and targets muscle power deficits specifically, is necessary to drive changes in both clinic and community-based walking activity. In this randomized multi-site clinical trial, 48 ambulatory participants with CP will receive either PT³ or an equivalent dosage of traditional strength training combined with traditional treadmill training (comparison group) for 24 sessions, 3 times per week for 8 weeks. Outcomes will be collected at baseline and immediately post-treatment. Short and long-term retention effects will be assessed at 2 and 6 months post.

Training will consist of unilateral and bilateral leg presses, targeting the quadriceps, hip extensors, and plantarflexors according to resistance training guidelines for muscle power training. The interval treadmill training portion will include short-bursts (30 seconds) of high speed walking intervals alternating with 30 seconds of low to moderate speed walking for a total of 30 minutes. Participants will train 3 x per week for 8 weeks. Total duration of each session will be approximately 1 hour.

Training will consist of unilateral and bilateral leg presses, targeting the quadriceps, hip extensors, and plantarflexors following the dosing and resistance training guidelines for muscle strength. Traditional treadmill training will consist of walking at steady-state speeds for 30 minutes. Participants will train 3 x per week for 8 weeks. Total duration of each session will be approximately 1 hour.

Average strides/day as captured by Step Watch accelerometer as worn for 5 days (Community walking activity level)

Average strides/day as captured by Step Watch accelerometer as worn for 5 days (Community walking activity level)

Ultrasound image of cross-sectional area of rectus femoris at 50% distance between anterior superior iliac spine and apex of patella

Isokinetic dynamometer (Biodex System 3) according to published standard procedures for isokinetic strength. Calculated for knee extensors, ankle plantarflexors.

Average strides/day in low (1 to 30 strides/min), medium (31 to 60 stride/min), and high (> 60 stride/min) stride rates as captured by Step Watch accelerometer as worn for 5 days.

Patient-Reported Outcomes from NINDS Common Data Elements - CP; The PROMIS item bank was developed from patient-reported outcome measures that indicate patients' state of well-being and functional abilities

Inclusion Criteria: Diagnosis of bilateral spastic Cerebral Palsy (CP) Age 10 to 17 years inclusive GMFCS levels I, II, or III Exclusion Criteria: Orthopedic or neurosurgery less than 12 months prior to enrollment Injection therapies (phenol, botulinum toxin) less than 3 months prior to enrollment Lacking greater than 25 degrees of knee extension