Section Information: Abstracts of Platform and Poster Presentations for the 2005 Combined Sections Meeting: Platform Presentations
PURPOSE/HYPOTHESIS: This study examines the efficacy of manual hamstring stretching in children with spastic cerebral palsy (CP).
NUMBER OF SUBJECTS: Eleven children were included, ages 5 to12 years (Mean 9.2, sd 2.5), representing Gross Motor Function Classification System levels 1 to 4.
MATERIALS/METHODS: For each subject, one leg was randomly assigned to receive intervention and the other leg served as a control. Hamstring flexibility was tested on both legs before and after intervention, using a Biodex dynamometer. Variables included: 1) angle in degrees when minimal torque (0.5 Nm) was recorded (Ao), 2) angle when maximum subject tolerance was reached (Amax), 3) torque at Amax (Tmax), 4) Amax-Ao, 5) slope of the line from Amax to Ao on the torque-angle curve (Stiffness), and 6) angle at the highest common torque level achieved across tests (A-HCT). Range of motion (ROM) as measured by Amax reflects stretch tolerance (Tmax) and muscle length (A-HCT). Intra- and inter-session reliability were demonstrated. Intervention was provided by a physical therapist assistant five days per week for eight weeks, including five repetitions of a 60 second hamstring stretch at maximal tolerance without pain. Descriptive statistics were calculated including the treatment minus control mean difference (MnDiff), standard error of the mean (SE) and coefficient of variation (CV). A Wilcoxon signed-rank test compared the distribution of the change values between treated and control legs.
RESULTS: Following intervention, a significant increase on the treatment side relative to the control side occurred for Amax (P = 0.01) (MnDiff 11.6, SE 3.44, CV -98.46), Tmax (P = 0.05) (MnDiff 3.65, SE 1.53, CV 139.26), and A-HCT (p = <0.01) (MnDiff 7.4, SE 2.08, CV -93.12). No significant differences in Ao, Amax-Ao, or Stiffness occurred on the treatment side relative to the control side (P > 0.05). On the treated side, significant increases occurred for Amax (MnDiff 8.7, P = 0.001), and Tmax (MnDiff 4.8, P = 0.003), with no significant change in A-HCT (MnDiff 0.9, P > 0.05). The control side showed a significant decrease in A-HCT (MnDiff 6.5, P = 0.03), with non-significant changes in Amax (MnDiff -2.9 P = 0.9) and Tmax (MnDiff 1.1 P = 0.3).
CONCLUSIONS: Improvement in ROM (Amax) on the treated side was primarily due to increased stretch tolerance (Tmax), since A-HCT did not change significantly. A-HCT significantly decreased on the control side, indicating a loss of muscle length, with a non-significant increase in stretch tolerance (Tmax) and no significant increase in hamstring ROM (Amax).
CLINICAL RELEVANCE: Flexibility testing using the Biodex allows assessment of muscle length, stretch tolerance, and the combination (ROM). This study suggests manual hamstring stretching can improve ROM, primarily by increasing stretch tolerance. Because a significant loss of muscle length (A-HCT) was seen on the control side, but not the treatment side, hamstring stretching as applied in this study may impede contracture progression.