In the current study, the BMT group did not demonstrate the advantage for proximal motor function reported by previous studies comparing unilateral and bilateral treatments (Lin et al., 2009; Yang et al., 2012). On the basis of research findings that deficits in proximal arm muscle synergies are correlated with motor function (Roh et al., 2015), the proximal arm motor improvements in the IMT group may be related to the normalization of proximal muscle synergies.