Fitness and strength responses to distinct exercise modes in twins: Studies of Twin Responses to Understand Exercise as a THerapy (STRUETH) study.

This study has implications for those charged with optimising the benefits of exercise by means of individualising the exercise prescription. ABSTRACT: Exercise response is idiosyncratic, but the degree of responsiveness, concordance in response between modalities and genetic contribution to responsiveness are not well understood. We investigated this using a novel randomised cross-over design of dichotomous exercise interventions in mono-(MZ) and di-zygotic (DZ) twin pairs. We studied strength (1RM) and fitness (VO2 max) responses in 84 same-sex untrained twins (30MZ, 12DZ pairs; 24.9 ± 5.4 yr). Twins, as pairs, underwent 3 months of resistance (RES) and endurance (END) training, separated by a 3 month washout period. Training responses and genetic/environmental contributions to responses were assessed. Leg strength 1RM increased following RES but not END (△47 ± 29vs3±26 kg; P < 0.001), whilst VO2 max increased following END but not RES (△0.25 ± 0.26vs0.04 ± 0.25L.min-1 ; P < 0.001). A higher percentage of individuals responded to RES for strength and to END for VO2 max (P < 0.0001). Within-individual responses to each mode weren't correlated (P > 0.05). Cross-sectional intraclass correlations were higher for MZ than DZ pairs for all variables, due largely to shared environment. Following training, MZ, but not DZ pairs, were significantly correlated for strength change to RES (rMZ = 0.62, P = 0.002) and END (rMZ = 0.36, P =...
Source: Physiological Research - Category: Physiology Authors: Tags: J Physiol Source Type: research