Mental Fatigue From Smartphone Use Reduces Volume-Load in Resistance Training: A Randomized, Single-Blinded Cross-Over Study. Issue 4 (August 2021)

• Record Type: Journal Article
• Authors: Gantois, Petrus; Lima-Júnior, Dalton de; Fortes, Leonardo de Sousa; Batista, Gilmário Ricarte; Nakamura, Fábio Yuzo; Fonseca, Fabiano de Souza
• Is Part Of: Perceptual and motor skills. Volume 128:Issue 4(2021)
• Page Start: 1640
• Page End: 1659
• Publication Date: 2021-08
• Subjects: mental fatigue -- resistance exercise -- perceived exertion -- concentric mean velocity -- volume-load; Perception -- Periodicals; Motor ability -- Periodicals; Motor Skills; Perception; Psychology; Electronic journals; Periodicals; 152
• DOI: 10.1177/00315125211016233
• Languages: English
• ISSNs: 0031-5125

Abstract

We investigated the acute effects of mental fatigue induced by 30-minute use of smartphone social network apps on volume load in resistance training among recreationally trained adults. Sixteen (n = 16) adults of both sexes performed three sets of a half back-squat exercise to failure with 80% of 15RM, interspersed with 3-minutes of passive recovery between sets, before and after two different cognitive tasks: (a) use of smartphone social network apps; and (b) watching a documentary. We assessed mechanical variables and ratings of perceived exertion during the strength exercise. Relative to the documentary-viewing control condition, a 30-minute exposure to smartphone social network apps led participants toward increased perception of mental fatigue ( p = 0.004) and lower volume-load during the strength exercise ( p = 0.006). There were no significant differences in perceived exertion between conditions ( p = 0.54), participants' motivation ( p = 0.277), intra-set mechanical variables ( p > 0.05), or blood lactate concentrations ( p = 0.36). Our findings of an isolated possible higher-than normal RPE without changes in physiological variables, accompanying the lower volume-load in the mentally-fatigued participants support psychological, rather than physiological, bases for mental fatigue effects.