Effects of intra-set rest on morphological variables, maximal strength and jump performance in university students

The appropriate dosage of resistance training could promote physical and physiological adaptations and decrease injuries. The aim of the study was to analyze the effects of the different intra-set rest after eight weeks of resistance training on morphological variables, maximal strength, and jump performance in physically active university students. Twenty-five students (15 men and 10 women) were randomized by sex and distributed in Control Group (CG) (n=8) with rest only at the end of the series; Experimental Group 1 (EG1) (n=9) with an intra-set rest of 30 s, and Experimental Group 2 (EG2) (n=8) with four intra-set rest of 10 s. Morphological variables [body weight, bipedal height, body mass index (BMI), fat mass and muscle mass], maximum upper body strength (bench press and military press), lower body strength [parallel squat (45°) and deadlift], as well as countermovement jump (CMJ) were measured. All three groups obtained a significant increase (p<0.01) in body weight and BMI, as well as an essential reduction (p<0.01) of fat mass. Muscle mass increased significantly (p<0.01) for both CG and EG1. Maximum upper-and lower-body strength increased considerably (p<0.05) across all three groups and for all exercises, while the CMJ notably increased for CG and EG1. There are no significant changes between the different intra-set rest, when using the same volume, intensity, and total recovery time during the exercise series (p>0.05); thereby, there is an equivalent increase in muscle mass, maximal strength, jump performance, and a fat mass reduction.