Resumen de Low-Load Resistance Training Performed to Muscle Failure or Near Muscle Failure Does Not Promote Additional Gains on Muscle Strength, Hypertrophy, and Functional Performance of Older Adults
Joao Guilherme Almeida Bergamasco, Deivid Gomes da Silva, Diego Fernandes Bittencourt, Ramon Martins de Oliveira, Jose Carlos Bonjorno Junior, Flavia Rossi Caruso, Daniela Godoi, Audrey Borghi-Silva, Cleiton Augusto Libardi
The aim of the present study was to compare the effects of low-load resistance training (RT) protocols performed to failure (FAI), to voluntary interruption (VOL), and with a fixed low repetitions (FIX) on muscle strength, hypertrophy, and functional performance in older adults. Forty-one subjects (60-77 years) were randomized into one of the RT protocols (FAI, VOL, or FIX) and completed 12 weeks of RT at 40% of 1 repetition maximum (1RM), twice a week. The assessments included 1RM test, muscle cross-sectional area (CSA), rate of torque development (RTD), and functional performance (chair stand [CS], habitual gait speed [HGS], maximal gait speed [MGS], and timed up-and-go [TUG]). All protocols significantly increased 1RM values from Pre (FAI: 318.3 +/- 116.3 kg; VOL: 342.9 +/- 93.7 kg; FIX: 328.0 +/- 107.2 kg) to Post (FAI: 393.0 +/- 143.1 kg, 23.5%; VOL: 423.0 +/- 114.5 kg, 23.3%; FIX: 397.8 +/- 94.6 kg, 21.3%; p < 0.0001 for all groups). Regarding CS, all protocols showed significant improvements from Pre (FAI: 11.5 +/- 2.4 seconds; VOL: 12.1 +/- 2.5 seconds; FIX: 11.3 +/- 1.1 seconds) to Post (FAI: 10.5 +/- 1.1 seconds, -8.5%, p = 0.001; VOL: 10.3 +/- 1.5 seconds, -15.1%, p = 0.001; FIX: 11.0 +/- 1.1, -3.2%, p = 0.001). Habitual gait speed values increased significantly from Pre (FAI: 1.3 +/- 0.2 m[middle dot]s-1; VOL: 1.3 +/- 0.1 m[middle dot]s-1; FIX: 1.3 +/- 0.1 m[middle dot]s-1) to Post (FAI: 1.4 +/- 0.2 m[middle dot]s-1, 2.5%, p = 0.03; VOL: 1.4 +/- 0.2 m[middle dot]s-1, 5.2%, p = 0.036; FIX: 1.4 +/- 0.1 m[middle dot]s-1, 5.7%, p = 0.03). No significant differences between protocols were found (p > 0.05). In addition, there were no significant changes in CSA, RTD, MGS, and TUG for any protocols (p > 0.05). In conclusion, low-load RT performed without muscle failure promotes significant improvements in muscle strength and some parameters of functional performance in older adults.
