Predicting the Efficacy of Resistance Exercise Training for Improving Endurance Performance

Identifying Molecular Determinants for the Efficacy of Resistance Training for Improving Endurance Performance in Elite Cyclists

The overall objective of the study is to identify molecular determinants of the efficacy of resistance training for improving endruance performance in elite cyclists

For elite endurance athletes, the addition of resistance training to habitual endurance training routines generally leads to improved endurance performance. However, this is not always the case, with several individuals failing to respond in the expected manner. This inter-individual variation is likely associated with inherent cellular and molecular charateristics of skeletal muscle. Indeed, responses to resistance training seem to be associated with muscle biological characteristics such as muscle fiber composition and ribosomal content (during the early phase of resistance training).

The study will investigate the association between muscle fibre composition (type I vs type II muscle fiber proportions) / ribosomal content in m. vastus lateralis and the effects of 10 weeks of resistance training on endurance performance in 52 elite cyclists. Half the participants will perform resistance training in addition to their habitual endurance training routines, the other half will perform endurance training-only. Muscle biopsies will be sampled from m. vastus lateralis before and after the first two weeks of the intervention. For muscle fiber composition, the hypothesis is that larger proportions of type II fibers will be associated with more pronounced benefits of resistance training. For ribosomal content, the hypothesis is that higher rRNA content at baseline and larger increases in rRNA content during the initial part of the intervention will be associated with more pronounced benefits of resistance training. No changes are expected in the non-resistance training control group.

Inclusion criteria:

• VO2max > 65 ml/kg/min (male participants)
• VO2max > 50 ml/kg/min (female participants)
• >7 hours of endurance training per week for the 6 months leading up to the study

Exclusion criteria:

- having conducted regular resistance training for the last 6 months leading up to the study