Cross Education Theory

1. Introduction

Cross education is the process by which unilateral training of one limb gives rise to enhancements in the performance of homologous muscles in the other limb. Although it is widely agreed that cross education occurs following training there has been an extensive hiatus in research on the phenomenon and the mechanistic basis remains elusive. However, as studies begin to reveal a possible therapeutic application of cross education, particularly in patients with spinal cord injury, selected neuromuscular disorders, spastic hemiparesis, knee arthroplasty and in patients with orthopaedic deficits, a larger body of research is needed to delineate the processes underlying cross education so that patient-specific rehabilitation programmes

The aim of this review is to explore the theories of cross education, to detail how our understanding and thinking has changed due to experimentation and to recommend a path for further study in an effort to elucidate information on the expression of cross education of movement

The result showed an improved ability to perceive tactile sensation not only in the ‘trained’ fingers but also of the right, contralateral fingertips despite not using them at any point during the training protocol. This work bred interest in Edward Wheeler Scripture of a possible inter-limb exchange of skill and strength. Scripture found that, as was to be expected, strength training (squeezing a rubber bulb) of the right hand led to increases in strength of that hand by 70%. He called this the training effect within the trained limb. However, more interestingly, he found an increased strength in the untrained limb of approximately 43%, which he attributed to ‘indirect practice’. Similarly, he tested for skill training and transfer following repetitive threading of a needle through electrified holes. His results showed an increase in accuracy by 40% in the trained limb and 20% in the untrained limb . These findings laid the basis to describe a novel phenomenon which seemed to transfer both increases in strength and enhancements in skill from a trained limb to an untrained limb. Since then, many of the aspects of cross education have been characterised through research. It is now known that cross education is not confined to any particular muscle group, being recorded in both upper and lower limbs, from small intrinsic