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Updated: Jul 19, 2026
Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
Quadriceps and hamstring strength changes as a function of selective dorsal rhizotomy surgery and rehabilitation
S A Ross1, J R Engsberg, K S Olree
1Human Performance Laboratory (S.A.R., J.R.E., K.S.O), Barnes-Jewish and St. Louis Children’s Hospital, St. Louis, Mo; Washington University School of Medicine and St. Louis Children’s Hospital (T.S.P., J.R.E), St. Louis, Mo.
Insights
Selective dorsal rhizotomy surgery (SDR) and rehabilitation significantly improved knee strength in children with cerebral palsy (CP). Children with CP remain weaker than those without disabilities but show measurable strength gains post-treatment.
Area of Science:
- Neurology
- Orthopedics
- Pediatrics
Background:
- Objective strength measures are crucial for evaluating interventions in children with cerebral palsy (CP).
- Selective dorsal rhizotomy (SDR) is a surgical option for managing spasticity in CP, often followed by rehabilitation.
- The impact of SDR and rehabilitation on muscle strength in children with CP requires further objective quantification.
Purpose of the Study:
- To quantify quadriceps and hamstring strength in children with CP before and eight months after SDR.
- To compare strength measures between children with CP and a typically developing group.
Main Methods:
- Nineteen children with CP and 20 children without disabilities (WD) underwent isokinetic dynamometry testing.
- Maximum concentric contractions of quadriceps and hamstring muscles were assessed at 10 degrees/second.
- Peak torque and work (extension/flexion) were recorded from torque-angle data.
Main Results:
- Children with CP, both pre- and post-SDR, demonstrated significantly lower strength across all measures compared to the WD group.
- Following SDR and rehabilitation, children with CP exhibited significant increases in peak torque and work values.
- These findings confirm that children with CP are weaker than their peers, with strength improvements noted after SDR and rehabilitation.
Conclusions:
- Selective dorsal rhizotomy surgery combined with rehabilitation leads to significant improvements in knee strength in children with cerebral palsy.
- While children with CP remain weaker than their non-disabled peers, the study provides objective evidence of strength gains post-intervention.
Purpose:
Objective measures of strength in children with cerebral palsy (CP) are needed to determine the effect that selective dorsal rhizotomy surgery (SDR) and subsequent rehabilitation have on muscle strength. This investigation quantified quadriceps and hamstring strength in children with CP pre-SDR and eight months post-SDR.
Method:
Nineteen children with CP and 20 children without disabilities (WD group) were tested with an isokinetic dynamometer. The children performed a maximum concentric contraction of the quadriceps muscles as the dynamometer moved the knee from a flexed position to an extended position at 10 degrees per second. A maximum concentric contraction of the hamstring muscles was then performed as the knee was moved from extension to flexion. Four variables were recorded from the torque-angle data; peak extension and flexion torque and extension and flexion work.
Results:
Children with CP, both pre- and post-SDR were significantly weaker in all strength measures compared with the WD group. Children with CP post-SDR and rehabilitation had significantly greater peak torque and work values compared with their pre-SDR values. The results agreed with previous studies indicating that children with CP are weaker than their peers without disabilities. Previous studies on strength changes after SDR remain controversial.
Conclusions:
The results of this study showed a significant increase in strength at the knee after rhizotomy and rehabilitation.
