Author(s): CHENG, C.F., YANG, Y.R.2, GOH, C.M.1, LIN, C.Y.1, CHAN, K.H.1, Institution: NATIONAL TAIWAN NORMAL UNIVERSITY, Country: TAIWAN, Abstract-ID: 305

INTRODUCTION:
The 7-min workout (7MW) is a bodyweight-based high-intensity circuit training that has become widely popular and proposed to improve aerobic fitness and fat loss [1]. However, limited studies have examined the effects of 7MW on fitness and health, with one previous study reporting cardiovascular responses to 7MW at the low bound of the vigorous intensity spectrum [2]. Blood flow restriction (BFR) has been reported to increase neuromuscular and metabolic stress, thus improving aerobic and muscular fitness [3]. This study examined the effects of 7MW combined with BFR on aerobic capacity, muscular fitness, and body composition in healthy adults.
METHODS:
Thirty-three active and healthy males were recruited and randomly assigned into 7MW, 7MW+BFR, and control (CON, no intervention) group. The 7MW and 7MW+BFR groups performed a 6-wk (3 sessions/week; 1 set in the first 3-wk, 2 sets for the rest of weeks) of 7MW training program. The vascular occlusion (150 mmHg) was administered on both thighs in 7MW+BFR group during exercise. Session rating of perceived exertion (s-RPE) was obtained 30-min after each training session. Participants performed countermovement jump (CMJ), isometric mid-thigh pull (IMTP) test, graded cycling exercise test (GXT), and measurements of skinfold thickness (chest, abdomen, thigh) and thigh circumference (TC) before and after intervention. The blood lactate levels were measured before and after GXT.
RESULTS:
The s-RPE in the last 3-wk was significantly higher in 7MW+BFR (8.9 ± 1.0) than in 7MW (8.3 ± 1.0, p < 0.05). However, no significant differences were found in s-RPE between the 7MW and 7MW+BFR groups. During the last 3-wk, the number of repetitions of push-up, step-up onto chair, squat, triceps dip on chair, and push-up and rotation at the second set were significantly lower in 7MW+BFR than in 7MW (p < 0.05). Maximum oxygen uptake increased significantly after 7MW (from 50.5 ± 6.1 to 53.6 ± 5.8 ml/kg/min; +6.4%) and 7MW+BFR (from 49.3 ± 5.5 to 51.7 ± 5.4 ml/kg/min; +5.2%) interventions. The peak (+12.0%) and mean (+11.3%) force during IMTP enhanced significantly in 7MW+BFR, but no significant changes were found in 7MW (+4.5%; +5.3%) and CON (-6.1%; -6.7%). Changes in peak and mean force during IMTP were significantly higher in 7MW+BFR than in CON (p < 0.05). There were no significant interaction effects for CMJ height, maximal rate of force development during IMTP, sum of skinfold thickness, TC, and blood lactate levels. However, abdominal skinfold thickness increased significantly in CON.
CONCLUSION:
Both 7MW and 7MW+BFR might improve the aerobic capacity in active males but might not affect power and body composition. Integrating the vascular occlusion into a 6-wk 7MW program might further increase muscular strength. Supported by grants from Ministry of Science and Technology, Taiwan (MOST 111-2410-H-003-139-MY2). References: [1] Klika, B. & Jordan, C. (2013) [2] Riegler, M., et al. (2017) [3] Silva, J., et al. (2019). Contact: andescheng@ntnu.edu.tw