The range of motion of the back squat exercise affects absolute volume load without changing the rating of perceived exertion / A amplitude de movimento no agachamento afeta o volume absoluto sem modificar a percepção de esforço

Abstract The range of motion (ROM) may affect the external maximal load during back squat (BS) exercise. The correct ROM manipulation can be useful as an exercise load manipulation strategy, changing the volume load during a resistance training session. The aim of this study was to evaluate the acute effects of ROM on relative load, absolute load and the rating of perceived exertion (RPE) during partial and full BS exercise with adjusted loads. Fifteen male individuals (age: 26.5±4.5 years; height: 173±6 cm; body mass: 80.6 ± 8.8 kg; resistance training experience 5±3 years) participated in this study. The experimental procedure was conducted in two sessions. In the first session, brief familiarization and a 10-repetition maximal test (10-RM) was performed for partial (PBS) and full BS exercise (FBS) with 30-min of rest interval. During the second session, all subjects performed 1 set of 10-RM in both conditions (partial and full ROM), and relative load, absolute load, and RPE were evaluated. A paired t-test was used to compare means. The results showed higher values for PBS when compared to FE exercise: relative load (PBS: 1.14±0.24xBW vs. FBS: 0.87±0.24xBW; P<0.001), and absolute load (PBS: 925±249 kg x FBS: 708±232 kg, P<0.001). Similar RPE was observed between conditions (PBS: 8.6±1.3 IEP x FBS: 8.5±1.0 IEP, P=0.855). It was concluded that PBS allowed higher relative load and absolute load during 10RM, without effects on RPE.

Resumo A amplitude de movimento durante o exercício agachamento pode afetar a sobrecarga imposta ao sistema neuromuscular. Desta forma, a manipulação da amplitude de movimento pode ser utilizada como estratégia de manipulação da sobrecarga do exercício, alterando o volume absoluto da sessão de treinamento bem como os ajustes agudos do sistema neuromuscular. O objetivo do presente estudo foi avaliar os efeitos agudos da amplitude de movimento na sobrecarga relativa, volume absoluto e na percepção subjetiva de esforço (PSE) durante o exercício agachamento total e parcial com sobrecargas ajustadas. Participaram do estudo 15 homens (idade: 26,5±4,5 anos; estatura: 173±6 cm; massa corporal total: 80,6±8,8 kg; e tempo de prática no treinamento de força 5±3 anos). O experimento foi conduzido em duas sessões. Na primeira sessão, foi realizada a familiarização, coleta dos dados antropométricos e determinação de 10 repetições máximas (RMs) para o exercício agachamento parcial (AP) e total (AT). Na segunda sessão, os voluntários realizaram 10-RMs no exercício AP e AT com as sobrecargas ajustadas. Então, os participantes foram orientados a reportar a PSE. Um teste t de student pareado foi utilizado para comparar as médias. Os resultados mostram maior volume relativo (AP: 1,14±0,24xMC vs. AT: 0,87±0,24xMC; P<0,001) e volume absoluto (AP: 925±249 kg vs AT: 708±232 kg, respectivamente, P<0,001) no agachamento parcial quando comparado ao total. A PSE não apresentou diferenças significantes entre amplitudes (AP: 8,6±1,3 vs AT: 8,5±1,0; P=0,855). Conclui-se que a realização do AP possibilita a produção de maior volume absoluto e não influencia a PSE.

Comparison Between Pre-Exhaustion and Traditional Exercise Order on Muscle Activation and Performance in Trained Men.

The purpose of this study was to measure the acute effects of pre-exhaustion vs. traditional exercise order on neuromuscular performance and sEMG in trained men. Fourteen young, healthy, resistance trained men (age: 25.5 ± 4.0 years, height: 174.9 ± 4.1 cm, and total body mass: 80.0 ± 11.1 kg) took part of this study. All tests were randomized and counterbalanced for all subjects and experimental conditions. Volunteers attended one session in the laboratory. First, they performed ten repetition maximum (10RM) tests for each exercise (bench press and triceps pushdown) separately. Secondly, they performed all three conditions at 10RM: pre-test (bench press and triceps pushdown, separately), pre-exhaustion (triceps pushdown+bench press, PE) and traditional (bench press+triceps pushdown, TR), and rested 30 minutes between conditions. Results showed that pre-test was significantly greater than PE (p = 0.031) but not different than TR, for total volume load lifted. There was a significant difference between the pre-test and the time-course of lactate measures (p = 0.07). For bench press muscle activity of the pectoralis major, the last repetition was significantly greater than the first repetition (pre-test: p = 0.006, PE: p = 0.016, and TR: p = 0.005). Also, for muscle activity of the triceps brachii, the last repetition was significantly greater than the first repetition (pre-test: p = 0.001, PE: p = 0.005, and TR: p = 0.006). For triceps pushdown, muscle activity of the triceps brachii, the last repetition was significantly greater than the first repetition (pre-test: p = 0.006, PE: p = 0.016, and TR: p = 0.005). For RPE, there were no significant differences between PE and TR (p = 0.15). Our results suggest that exercise order decreases repetitions performed, however, neuromuscular fatigue, lactate, and RPE are not impacted. The lack of difference in total volume load lifted between PE and TR might explain, at least in part, the similar metabolic and perceptual responses. Key pointsThe effects of different exercise order schemes (e.g. PE and TR) on muscle activity and strength performance indicated that similar responses were observed when comparing these schemes.Strength and conditioning coaches should consider these results when prescribing resistance training programs.The primary target (e.g. muscle group) of the training session should trained first, when fatigue level low, in order to maximize training outcomes.