Cerebral Palsy: Short-burst Interval Training

This study examines the effect of short burst interval treadmill training in ambulatory children with cerebral palsy. Half the sample will receive 20 sessions of training over 4 weeks, while half will receive the training over 10 weeks.

Ambulatory children with cerebral palsy (CP) experience activity limitations which negatively influence their ability to physically participate in day to day life. Therefore, these children are at greater risk for inactivity and functional decline with age. In contrast, typically developing (TD) children engage in short bursts of intense physical activity interspersed with varying intervals of low and moderate intensity within their natural environment. These physical activity patterns are very different from adult patterns Despite these inherent differences, locomotor treadmill training (LTT) protocols designed to improve walking activity in children with CP simulate adult protocols, consisting of continuous low to moderate walking endurance activity. Body weight supported or robot assisted LTT is based on the underlying premise of modifying neural circuitry via spinal pathways. However, this type of training has not been shown to be more effective than other comparable interventions and presents with significant fiscal and logistical barriers to clinical translation. This study will determine the effect of short-burst interval LTT without body weight support on the primary outcomes of walking performance and capacity and the secondary outcomes of day-to-day mobility based participation in children with CP with functional walking limitations. To identify key muscular mechanisms associated with improved walking mobility, the investigators will examine the effects of short-burst interval LTT on quadriceps muscle performance and architecture. Secondarily, the study team will collect preliminary data on two LTT dosing frequencies.

Muscle function assessor masked to frequency group, Muscle architecture captured via ultrasound Community walking activity collected by accelerometry, thus non-human data collection

Participants receive short burst interval treadmill training for a total of 20 sessions. They are randomized to receive it either 5x/week for 4 weeks

Participants receive short burst interval treadmill training for a total of 20 sessions. They are randomized to receive it either 2x/week for 10 weeks

SBLTT consists of interval training consisting of short-bursts (30 seconds) of vigorous intensity locomotor treadmill training (LTT) alternating with low to moderate intensity LTT.,

Average stride per day as measured by StepWatch accelerometry. StepWatch accelerometer stride counts per day ( minimum of 8 hrs/day wearing time) were averaged a crossed 5 days (4 weekdays and 1 weekend day) to create Average Strides/day variable

Average Strides/day > 30 strides/min as measured by StepWatch accelerometry High Versus Low Frequency SBLTT Groups

Knee extensor muscle power - isotonic muscle power as measured by Biodex testing High Versus Low Frequency SBLTT Groups

Knee extensor muscle strength - isometric muscle strength as measured by Biodex testing High Versus Low Frequency SBLTT Groups

Rectus femoris mid thigh cross-sectional area as measured by 2D B Mode Ultrasound High Versus Low Frequency SBLTT Groups

Rectus femoris mid thigh fascicle length as measured by 2D B Mode Ultrasound High Versus Low Frequency SBLTT Groups

Inclusion Criteria: Ambulatory children with cerebral palsy Spasticity primary movement disorder Bilateral motor impairment (Diplegia) Gross Motor Function Classification System Levels II and III Exclusion Criteria: undergone orthopedic or neurosurgery less than 12 months prior injection therapies (phenol, botulinum toxin) less than 3 months prior