Bicycle pedal kinetics following force symmetry feedback training in subjects with unilateral cerebrovascular accident

The purpose of this study was to compare individual pedal reaction force co mponents following bicycle training with and without effective force feedba ck in subjects with unilateral cerebrovascular accident (CVA). Eight ambula tory subjects with CVA were studied on a recumbent bicycle equipped with cu stom-built pedals, which measure normal and tangential components of the lo ad applied to the pedal surface. Comparisons of normal and tangential pedal reaction forces were made following 1 month of bicycle training (3 times/w eek for 3 weeks) during retention tests performed without feedback. The rat ios of involved to contralateral (I/C ratios) force parameters were used to assess symmetry. Subjects were randomly assigned to 2 groups: (a) a feedba ck group that received visual/verbal. feedback regarding Effective force pa tterns, bilaterally, after each trial; and (b) a no-feedback group that rec eived no feedback. Two critical results were found: (a) tangential pedal fo rces were significantly more posteriorly directed bilaterally following tra ining across all subjects, but the change war; greater for the no-feedback group relative to the feedback group, and (b) effective force feedback trai ning did net demonstrate improvements in the I/C ratios above that of the c ontrol group. A more posteriorly applied tangential pedal force may represe nt increased dorsiflexion and may suggest that bicycle training facilitated ankle control. The cyclical nature of cycling, however, may allow for natu ral patterns to develop without feedback or may require less frequent use o f feedback based on retention test performance.