Efeitos agudos de séries cluster no desempenho do exercício de agachamento costas, salto contramovimento e respostas psicofisiológicas em atletas jovens

Abstract

Modifications in the exercise routine, which increase the level of muscular demand, can cause high levels of acute fatigue, with consequent impairment to physical performance. The redistribution of intervals has proven to be effective in promoting the maintenance of this performance. The purpose of this study was to compare the effect of traditional and cluster sets protocols on the performance of mechanical and perceptual variables in the squat exercise in young athletes. A cross-over experimental design was carried out, in which three sets of eight repetitions were applied in three training protocols with redistributed intervals in different configurations, being a traditional protocol (TRD: 3x8:225s), Cluster 1 (CS1: 3x2x4:30s:180s) and Cluster 2 (CS2: 3x4x2:30s:90s). Eleven adolescent athletes, 4 boys (age = 15.5 ± 0.8 years; body mass = 54.3 ± 7.0 kg; height = 1.67 ± 0.04 meters; 1RM/body mass: 1.62 ± 0.19 kg) and 7 girls (age = 17.2 ± 1.4 years; body mass = 54.7 ± 6.3 kg; stature = 1.63 ± 0.08 meters; 1RM/body mass: 1.22 ± 0.16 kg), with more than 6 months of strength training experience, participated in the study. Body mass (kg) and height (cm) were collected by a digital scale (Filizola, Brazil) with 0.1kg precision and a manual stadiometer (Sanny, Brazil) with 0.1cm precision. Using a linear position transducer (Chronojump, Boscosystem, Spain) with sampling frequency of 1000 Hertz and resolution of 1 millimeter, the mean propulsive values of force in Newtons (MPF), power in Watts (MPP) and velocity in meters per second (MPV) were evaluated, as well as the decline and maintenance of force (MFD and MFM), power (MPD and MPM) and velocity (MVD and MVM), during the protocols. Squat intensity was adjusted using a 2nd order polynomial regression equation based on the respective velocities and loads used during the 1RM test protocol. In pre and post moments, the height of the vertical jump with countermovement (CMJ) was evaluated in centimeters, through a contact mat (Chronojump, Boscosystem, Spain) with a precision of 0.01cm, as well as the difference between moments (ΔCMJ). The rating of perceived effort (RPE) between sets (RPE-Set) and at the end of the session (RPE-Session), the assessment of delayed onset muscle soreness (DOMS), and the recovery state through the total quality of recovery scale (TQR) were collected. Statistical analysis was performed using Two- way repeated measures ANOVA, with Bonferroni post-hoc, adopting the significance value of p ≤ 0.05, through SPSS Statistics® v.20.0 software. Effect sizes were calculated using Hedges’ g, in a spreadsheet in Microsoft Excel® software. Differences were found in the Protocol factor for MPV (p=0.002; η²:0.475), MPP (p<0.01, η²:0.505), MVD (p<0.01, η²:0.560) MPD (p<0.01, η²:0.557), MVM (p<0. 01, η²:0.582) and MPM (p<0.01, η²:0.577), showing a post-hoc difference favorable to CS2 compared to TRD in these variables (p<0.01), and between CS2 and CS1 (p<0.05), for the variables MVM, MPM, MVD, MPD. A significant main effect for the Protocol was found for RPE-Set (p=0.003, η²: 0.436) and RPE-Session (p=0.003, η²: 0.435), only being significantly different for CS2 compared to TRD (p=0.008 and p=0.015, respectively). There was no difference in jump performance (CMJ: p=0.985, η²: 0.002; ΔCMJ: p=0.213, η²: 0.143) and DOMS (p=0.437, η²: 0.079) between protocols. These findings suggest that using CS with a greater number of intraset rest intervals may be more efficient, even when total intervals are equalized, showing better performance of mechanical variables and lower perceptual effort responses.