Author(s): ROMERO-ARENAS, S., JEREZ-MARTÍNEZ, A., GARCÍA DE FRUTOS, J.M., BORGES-SILVA, F., Institution: UNIVERSIDAD CATÓLICA DE MURCIA, Country: SPAIN, Abstract-ID: 1706

INTRODUCTION:
The importance of strength training extends beyond neuromuscular adaptations, encompassing also potential metabolic benefits. However, the relationship between strength training and improvements in skeletal muscle mitochondrial function, crucial for energy efficiency, is less well understood. This study focuses on exploring the oxidative capacity of the vastus lateralis in natural bodybuilders, using near-infrared spectroscopy (NIRS), to understand how strength training affects mitochondrial function.
METHODS:
Thirty men participated, divided into natural bodybuilders (n=15; 23.2±3.76 years; 180.3±4.63 cm; 89.5±7.23 kg) and a control group (n=15; 21.6±4.54 years; 177.6±6.25 cm; 82.1±3.31 kg). Following the methodology of Ryan et al. (1), arterial occlusions were applied to assess mitochondrial oxidative capacity, determined by the time constant (TC) from a mono-exponential function derived from the NIRS signal.
RESULTS:
A significant difference in TC was found between bodybuilders (24.7±6.27 s) and the control group (37.6±9.35 s), indicating a significantly lower TC in bodybuilders (p<0.001).
CONCLUSION:
The findings suggest that strength training in natural bodybuilders is associated with an increased mitochondrial oxidative capacity, as evidenced by a reduced TC. This implies that, in addition to neuromuscular adaptations, intensive strength training may promote energy efficiency at the cellular level. These results extend the understanding of the metabolic effects of strength training and underline the importance of including this type of training in sports programmes to optimise mitochondrial function.

1. Ryan et al. J Appl Physiol. 2012;113(2):175-183.