Individuals with a unilateral lower-limb amputation (LLA) rely heavily on their intact limb during daily physical activities. However, there is limited research on the resultant effects of this over-reliance on contractile properties of muscles in the intact limb.
To compare the muscle contractile properties of the intact limb among individuals with a unilateral LLA to those of age-matched able-bodied individuals, using tensiomyography.
This is a cross-sectional, observational study.
Nine men with a unilateral LLA and 10 able-bodied men (control) were included. Tensiomyography measures were obtained for 5 muscles: gastrocnemius lateralis (GL) and medialis (GM), rectus femoris, vastus lateralis (VL), and vastus medialis. Contraction time (Tc), delay time (Td), maximal displacement (Dm), and velocity of deformation (Vd) for each muscle were compared between groups.
Tc and Td for the GL and GM muscles were lower for the LLA than the control group (GL: P = .03, r = −0.51, P < .01, r = 0.67; GM: P = .02, r = 0.53, P = .07, r = 0.54, respectively). Dm and Vd of the VL were significantly smaller in the LLA than the control group (P < .01, r = 0.73, P < .01, r = 0.23, respectively).
Men with a unilateral LLA seem to have slower deformation of the gastrocnemius muscles and higher stiffness of the VL than able-bodied controls. These findings may be indicative of an overuse of the intact limb as a compensation for the unilateral LLA. The confirmation of these findings in a larger sample size is required to translate these findings to practice.