The effect of 4 and 6 weeks of resistance training on serum levels of myonectin and IGF-1 in sedentary young men

Myonectin is one of the well-known myokines and similar to insulin-like growth factor-1 (IGF-1) involves in cellular signaling pathways. The aim of this study was to survey the effect of resistance training length on serum levels of myonectin and IGF-1 and their relationship in sedentary young men. Fourteen volunteer non-physical education students (age 26.50±0.94, BMI 23.70±2.34) were randomly selected to participate in this semi-experimental study. For 6 weeks, the participants performed resistance training. The protocol consisted of 3 sessions per week and included 6 exercises (bench press, barbell curl, leg press, leg extension, leg curl, wide grip lat pull down), with 3 sets of 8-10-12 repetitions in each exercise and the intensity of 60 -70- 80 percent of one repetition maximum (respectively for first, second and third two weeks). Rest time between sets and exercises were determined two and three minutes, respectively. Blood samples were collected 24 hours before and 48 hours after four and six weeks of resistance training. The data were analyzed at significance level of p≤ 0.05, using 23th version of SPSS software. According to the results, there were no significant difference in serum levels of myonectin and IGF-1 after four weeks of resistance training (p=0.202, p=0.337 respectively). However, serum levels of myonectin and IGF-1 increased significantly after six weeks of resistance training (p=0.001, p=0.029 respectively). It should be noted that Pearson correlation coefficient did not show any significant relationship between myonectin and IGF-1 (p= 0.74: fourth week, p= 0.71: sixth week). The results showed four weeks of resistance training could not significantly change serum levels of myonectin and IGF-1 in sedentary young men, and to do that, at least 6 weeks of resistance training is required.