Performance psychology: the power of an uncluttered mind

Even the most dedicated athlete cannot live in a vacuum, and for most athletes, it’s not even a remote possibility! Between school, professional, family, and social obligations, there are a lot of competing demands on athletes of all types, ages, and experience levels. While all of these competing demands might not be physical in nature, they can require a lot mental input. These demands require engagement, concentration, focus, and they require effort - just as physical training and sport practice do.

Cost of mental fatigue

Just because there isn’t any physical exertion involved, it doesn’t mean there isn’t a performance cost involved to these mental activities. Unfortunately, it’s become evident that mental fatigue can have a negative impact on sports performance, even if no physical load is experienced. As examples, the impact of performing mentally fatiguing tasks prior to activity have been demonstrated during sports skill practice⁽¹⁾ and during endurance exercise⁽²⁾.

However, there is less agreement among scientists about what happens during short-term, more intense activities such as resistance training. For some athletes, these types of activities can comprise a significant portion of the total training load. If resistance training is compromised by mental fatigue as well, it’s important to understand the extent to which this the case so that individuals can adjust their training as appropriate. While intuitively, it makes sense that higher intensity training would be negatively impacted by fatigue in a similar manner to skill or endurance training, concrete evidence is always valuable.

New research on mental fatigue and physical performance

To determine the impact of mental fatigue on physical performance, a group of Spanish and Australian researchers have conducted new research on this topic⁽³⁾. In this study, the researchers performed a meta-analysis (a study that pools the data from all the previous studies on a topic) to determine whether performing resistance training while mentally fatigued would result in the completion of fewer repetitions compared to performing the same resistance training without mental fatigue. The researchers also investigated whether, if there was a link, it affected both lower body and upper body resistance training exercises equally. This meta-analysis combined the results of seven different studies, which resulted in the inclusion of 190 subjects for the upper body analysis and 124 subjects for the lower body analysis.

When the data were number crunched and analyzed, the results were very clear: the inclusion of mentally fatiguing activities prior to intense resistance exercise significantly reduced the number of repetitions subjects were able to achieve during a set. Indeed, the presence of mental fatigue, even in the absence of physical fatigue, negatively impacted performance. In short, if you want to optimize your resistance exercise performance, avoiding mentally fatiguing activities beforehand seems like the smart move!