Passive resistance of hamstring muscles in children with severe multiple disabilities?

The purposes of this study were to evaluate whether resistance to stretch could be measured in a reproducible manner from day to day in children with severe multiple disabilities, and whether 6 weeks of daily activity, including one daily stretch, would modify passive resistance to stretch. Passive resistance to stretch was measured in six children using an established model that synchronously and continuously measured knee flexion moment (Nm) and EMG activity of the hamstring, while the velocity and angle of a static stretch was controlled. Resistance to stretch was evaluated in the absence of EMG activity. Measurements were taken on two separate occasions with a 2-week hiatus, and before and after a 6-week activity period which included a daily 1-minute static stretch. There was no significant change in resistance to stretch when tested 2 weeks apart (test 1, 8.6 +/- 1.2 Nm; test 2, 8.3 +/- 1.2 Nm, p>0.05) which yielded a strong correlation coefficient (Spearman r=1.0, p<0.01; Pearson r=0.953, p<0.01). Similarly, there was no difference in resistance to stretch before and after the 6-week period (mean difference 0.22 +/- 0.75 Nm, p>0.05). Data from this study demonstrate that resistance to stretch of the hamstring muscle group could be measured in a reproducible manner from day to day in children with multiple disabilities. Further, resistance to stretch was unchanged after 6 weeks of daily activity, including a daily 1-minute static stretch.