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Effects of stretching and heat treatment on hamstring extensibility in children with severe mental retardation and hypertonia.
To examine the effect of heat and duration of stretching on the extensibility of hamstring muscles and their electromyographic responses to passive stretch in children with hypertonia and severe mental retardation.
Randomized cross-over trial.
Developmental disability unit in a local hospital.
Twenty-nine subjects (9 females) with ages ranged from 4 to 13 years with spastic and/or dystonic hypertonia and hamstring tightness.
Subjects received four treatment sessions in random order with each consisting of five repetitions of stretching: (A) 10-second stretching, (B) 30-second stretching, (C) hot pack followed by 10-second stretching, and (D) hot pack followed by 30-second stretching. Each treatment session comprised five repetitions of stretch and successive treatments were separated by at least 24 hours.
The distance between greater trochanter and lateral malleolus and hamstring electromyographic (EMG) activity during passive knee extension stretching.
Two-way ANOVA showed a larger increase in hamstring extensibility in conditions C and D (1.3 +/- 1.1 cm) than conditions A and B (0.7 +/- 0.9 cm) (P<0.001). For the EMG recordings, conditions B and D (-25.1 +/- 58.4 microV) had greater decrease than conditions A and C (-3.5 +/- 36.6 microV) (P= 0.039).
Heat application to the hamstrings before stretching could result in greater increase in extensibility than stretching alone in children with hypertonia and severe mental retardation. Stretching could promote relaxation of the hamstring muscles regardless of prior heat treatment. Stretching sustained for 30 seconds led to greater relaxation than that for 10 seconds.
Randomized Controlled Studies are High (Level A) design to appropriately measure an effect, impact, or causal relation. The study contains no serious weaknesses.
Based on this result you should conclude that the trustworthiness of the study is high (90%). This means there is a 10% chance that alternative explanations for the effect found are possible. The effect size was large and 95% CI was OK.