Cross-transfer effects in the upper extremity during an occupationally embedded exercise.

OBJECTIVE Cross-transfer effects were investigated during an occupationally embedded task that involved learning a fine motor skill. Cross-transfer is a phenomenon that occurs when an untrained limb receives some of the same benefits in performance from unilateral training that the contralateral limb received. It was hypothesized that cross-transfer would occur after a unilateral training regime using an occupationally embedded task. METHOD Forty-eight participants (mean age = 24.4 years) volunteered for this repeated-measures study. Participants were randomly assigned to a training or control group and were asked to complete a toy maze with their right and left hands for the pretest and posttest. Whereas participants in the control group did not train, participants in the training group completed a toy maze three times a day for 7 days with their left hands. All participants returned in 1 week to complete the posttest portion of the experiment. Dependent variables included movement time, movement units, force oscillations, and average force. RESULTS Significant decreases in movement time and force oscillations were found for the untrained limbs (p < .0125) in the training group. No significant differences were found in movement units or average force. The improved movement time and force oscillations in the untrained limb provides evidence suggesting that cross-transfer occurred. CONCLUSION This study indicates that with a population without impairments, cross-transfer can occur during an occupationally embedded task. This phenomenon may prove useful to the field of occupational therapy to rehabilitate immobilized extremities. Further research is needed to test this phenomenon with special populations.