Estudo do efeito de uma sessão de treino de força na musculação sobre as concentrações plasmáticas e urinárias de irisina em homens treinados

Abstract

Specific exercises for strengthening the musculoskeletal system, such as weight training, are recommended by the World Health Organization to obtain health benefits. In general, the health benefits promoted by physical exercise (PE) are a consequence of the adaptations induced in different tissues of the body. Part of these adaptations occurs through endocrine signaling mediators, such as irisin, which are released in response to exercise. The scientific literature has built a robust evidence base indicating that irisin promotes metabolic and neuronal benefits and that PE increases circulating irisin levels. Most of the studies that investigated this response used aerobic exercises. However, the acute effect of strength training, specifically in weight training, on the peripheral concentrations of irisin remains poorly understood. As a result, the general objective of this study was to study the effect of a strength training session in bodybuilding on plasma and urinary concentrations of irisin in trained adult men. The inclusion criteria were met by 14 healthy men experienced in strength training (age: 40.81±5.77 years; height: 174.5±5.898 cm; weight: 85.37±10.61 kg). The weight training protocol was composed of three exercises - bench press, leg press 45º, and closed anterior pulley. The protocol adopted consisted of four sets of maximum repetitions (RM) at 60% of 1 RM, with 120-second intervals between sets and exercises. The cadence used was one second of the concentric phase and two seconds of the eccentric phase (1"con:2"exc). Blood was collected before (baseline), immediately after, and one hour after strength training. Plasma samples were collected three times and urine samples before and up to one hour after the exercise. The concentration of irisin in plasma and urine was measured by the sandwich ELISA method. The analysis of the results shows that a strength training session at 60% of 1RM was able to increase lactate concentration from 1.193±0.3852 to 15.69±2.226 mmol/L significantly, a heart rate of 93.95 ±10.87 to 126.8±10.23 bpm and SPE PSE from 0 to 9.393±0.8069, however it did not change the irisin concentrations in the urine or plasma of the volunteers. A positive correlation was observed between the age of the volunteers and the plasma concentration of irisin before the performance of strength training. The present study showed that, although strength training-induced acute responses were typical of this type of protocol, a single strength training session in weight training did not alter plasma and urinary irisin concentrations in adult men experienced in strength training. Furthermore, it has been shown that in very physically active men, there is a direct association between age and basal plasma irisin concentration.