The Journal of Sports Medicine and Physical Fitness 2021 Feb 26

DOI: 10.23736/S0022-4707.21.12118-8

Copyright © 2021 EDIZIONI MINERVA MEDICA

language: English

Twice-daily sessions result in a greater muscle strength and a similar muscle hypertrophy compared to once-daily session in resistance-trained men

Daniel A. CORRÊA ¹, Felipe A. BRIGATTO ¹ ✉, Tiago V. BRAZ ¹, Jùlio B. B. de CAMARGO ¹, Marcelo S. AOKI ², Paulo H. MARCHETTI ³, Charles R. LOPES ^{1, 4}

¹ Human Performance Research Laboratory, Methodist University of Piracicaba, Piracicaba, São Paulo, Brazil; ² School of Arts, Sciences and Humanities, University of São Paulo, São Paulo, Brazil; ³ Department of Kinesiology, California State University, Northridge, CA, USA; ⁴ Adventist Faculty of Hortolândia, Hortolândia, São Paulo, Brazil

BACKGROUND: The present study investigated the mid-term effects of training muscle groups once- versus twice-daily on morphofunctional adaptations in trained men.
METHODS: Participants were randomly assigned to 1 of 2 experimental groups: 1 daily session per muscle group (1S, n = 11), where every muscle group was trained once a day or 2 daily sessions per muscle group (2S, n = 12), where every muscle group was trained twice. Testing was conducted before intervention and after 8 weeks for maximal strength (1RM) and muscular endurance (60%1RM) for bench press and parallel back squat exercises, and muscle thickness (MT) of the biceps brachii, triceps brachii, vastus lateralis, anterior quadriceps and pectoralis major.
RESULTS: The major findings were as follows: (a) the increase in 1RM back squat was significantly greater in 2S (Δ=16.1%) compared to 1S (Δ=7.8%) (p<0.05) and (b) both groups significantly increased bench press 1RM (1S: Δ=4.6%; 2S: Δ=6.8%), back squat 60% 1RM (1S: Δ= 19.0%; 2S: Δ= 24.3%), bench press 60% 1RM (1S: Δ= 15.4%; 2S: Δ= 24.0%) and all MT outcomes (p< 0.05 for all), with no differences between experimental groups (1S and 2S).
CONCLUSIONS: This study provides evidence that a twice-daily resistance training augments lower-body muscular strength; however, the daily frequency does not seem to have any additive effect on upper-body muscular strength, muscular endurance, and muscle hypertrophy in trained men.

KEY WORDS: Resistance training; Training frequency; Muscle thickness; Volume load