The Effect Of Intensity On Energy Expenditures In Male Resistance Training

Abstract

Resistance training can increase energy expenditures (EE) and improve body composition. But few studies have examined the acute EE response to resistance training when the number of reps and sets is the same but the intensity is different. PURPOSE: To investigate effects of intensity on aerobic, anaerobic and recovery EE in male resistance training. METHODS: Ten healthy male college students (age, 24.2 ± 1.3 years; height, 176.7 ± 6.6 cm; weight, 78.0 ± 10.5 kg; 1RM, 135.4 ± 17.3) were selected as subjects, and each of them carried out two experiments (the interval was at least 72 hours) using squat exercises. Each of the two experiments was combined with light intensity (LI: 0% or 20% 1RM), medium intensity (MI: 40% or 60% 1RM) and heavy intensity (HI: 70% or 80% 1RM). In each experiment, the load used for LI, MI and HI is selected by lot. First, subjects need a 15 min rest, then start LI. They were required to complete 3 sets of exercises 5 reps (2 s up and 2 s down). The interval time between sets was 4 min, and rest for 15 min after the completion of the third set. After that, MI and HI is carried out, and the process is consistent with that of LI. Blood lactate was collected 1 min before and 3, 5 and 7 min after training, and oxygen uptake was collected throughout the experiment. In this study, the EE is converted by the capacity-type measure method. RESULTS: 1. The aerobic EE of 80% 1RM (9.5 ± 2.2 kJ) during squat is was higher than other loads (p < 0.05), but there is no significant difference between other loads (7.0 ± 1.9 ~ 8.4 ± 1.8 kJ). 2. The anaerobic EE of 70% 1RM (15.0 ± 6.1 kJ) and 80% 1RM (25.0 ± 18.0 kJ) during squat was higher than other loads, (p < 0.05), and there was no significant difference between other loads (6.9 ± 7.1 ~ 11.2 ± 9.1 kJ). 3. There was a significant difference in recovery EE between different loads (p < 0.05). 4. There is a correlation between aerobic (r = 0.32; p < 0.05), anaerobic (r = 0.42; p < 0.001) and recovery (r = 0.86; p < 0.001) EE and load. When aerobic removal of 80%1RM, anaerobic removal of 70% and 80%1RM during exercise, there was no significant correlation between EE and loads. CONCLUSION: 1. Aerobic EE during squat seems to be less affected by light and medium intensity. 2. Load ≥70%1RM will increase anaerobic EE during squat. 3. recovery EE will increase with the increase of intensity, and it is more vulnerable to the impact of intensity.