Inter-limb transfer of ballistic motor skill following non-dominant limb training in young and older adults

Exp Brain Res (2013) 227:1929 DOI 10.1007/s00221-013-3481-9

RESEARCH ARTICLE

Inter-limb transfer of ballistic motor skill following non-dominant limb training in young and older adults

Mark R. Hinder Timothy J. Carroll Jeffery J. Summers

Received: 28 October 2012 / Accepted: 7 March 2013 / Published online: 28 March 2013 Springer-Verlag Berlin Heidelberg 2013

Because such tasks evoke similar neural responses to those observed following strength training (Selvanayagam et al. in J Appl Physiol 111:367375, 2011; Carroll et al. in Acta Physiol 202:119140, 2011), our ndings have important implications for rehabilitation paradigms following stroke or limb immobilisation due to injury.

Keywords Inter-limb transfer Ageing Ballistic movements Transcranial magnetic stimulation Symmetry/asymmetry of inter-limb transfer

Introduction

Repeated practice of a unilateral motor task not only results in performance improvements in the trained limb, but can also result in improvements in the contralateral limb (which undertakes no physical practice). This phenomenon is known as inter-limb, or cross-limb, transfer. A number of recent studies have investigated whether inter-limb transfer is manifested to a similar extent following training of the dominant or non-dominant limbs in a number of different adaptation paradigms. Criscimagna-Hemminger et al. (2003) and Wang and Sainburg (2004) reported that following a training protocol in which the dominant arm learned to compensate for external forces (i.e., dynamic force eld learning), the non-dominant (untrained) arm showed improved performance compared to nave performance levels. Transfer to the dominant limb following non-dominant limb practice was not, however, observed in either study. In contrast, Sainburg and Wang (2002) considered inter-limb transfer following adaptation to a novel visuomotor mapping. In this instance, transfer occurred from the dominant to non-dominant limb with respect to endpoint accuracy of movements, whereas transfer from non-dominant

Abstract We recently reported considerably less inter-limb transfer in older, compared to young, adults following dominant (right) hand motor training (Hinder et al. in J Appl Physiol 110:166175, 2011). This occurred despite the fact that both age groups exhibited similar performance improvements in the trained limb. However, asymmetries can exist with respect to the degree of transfer observed in some tasks, depending upon which limb undertakes the training. Accordingly, here we investigated inter-limb transfer following left hand ballistic motor training in young (n = 15; mean age 21.2 years) and older (n = 15;...