The Effects of Mental Fatigue on Physical Performance: A Systematic Review.

Background: Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity. It has recently been suggested that mental fatigue can affect physical performance. Objective: Our objective was to evaluate the literature on impairment of physical performance due to mental fatigue and to create an overview of the potential factors underlying this effect. \ud Methods: Two electronic databases, PubMed and Web of Science (until 28 April 2016), were searched for studies designed to test whether mental fatigue influenced performance of a physical task or influenced physiological and/or perceptual responses during the physical task. Studies using short (<30 min) self-regulatory depletion tasks were excluded from the review. Results: A total of 11 articles were included, of which six were of strong and five of moderate quality. The general finding was a decline in endurance performance (decreased time to exhaustion and self-selected power output/velocity or increased completion time) associated with a higher than normal perceived exertion. Physiological variables traditionally associated with endurance performance (heart rate, blood lactate, oxygen uptake, cardiac output, maximal aerobic capacity) were unaffected by mental fatigue. Maximal strength, power, and anaerobic work were not affected by mental fatigue. Conclusion: The duration and intensity of the physical task appear to be important factors in the decrease in physical performance due to mental fatigue. The most important factor responsible for the negative impact of mental fatigue on endurance performance is a higher perceived exertion

Mental fatigue: Impairment of technical performance in small-sided soccer games

© 2016 Human Kinetics, Inc. Purpose: To assess the effects of mental fatigue on physical and technical performance in small-sided soccer games. Methods: Twenty soccer players (age 17.8 ± 1.0 y, height 179 ± 5 cm, body mass 72.4 ± 6.8 kg, playing experience 8.3 ± 1.4 y) from an Australian National Premier League soccer club volunteered to participate in this randomized crossover investigation. Participants played 15-min 5-vs-5 small-sided games (SSGs) without goalkeepers on 2 occasions separated by 1 wk. Before the SSG, 1 team watched a 30-min emotionally neutral documentary (control), while the other performed 30 min of a computer-based Stroop task (mental fatigue). Subjective ratings of mental and physical fatigue were recorded before and after treatment and after the SSG. Motivation was assessed before treatment and SSG; mental effort was assessed after treatment and SSG. Player activity profiles and heart rate (HR) were measured throughout the SSG, whereas ratings of perceived exertion (RPEs) were recorded before the SSG and immediately after each half. Video recordings of the SSG allowed for notational analysis of technical variables. Results: Subjective ratings of mental fatigue and effort were higher after the Stroop task, whereas motivation for the upcoming SSG was similar between conditions. HR during the SSG was possibly higher in the control condition, whereas RPE was likely higher in the mental-fatigue condition. Mental fatigue had an unclear effect on most physical-performance variables but impaired most technical-performance variables. Conclusions: Mental fatigue impairs technical but not physical performance in small-sided soccer games

Acute and residual soccer match-related fatigue: A systematic review and Meta-analysis

BACKGROUND: Understanding soccer players' match-related fatigue and recovery profiles likely helps with developing conditioning programs that increase team performance and reduce injuries and illnesses. In order to improve match recovery (the return-to-play process and ergogenic interventions) it is also pivotal to determine if match simulation protocols and actual match-play lead to similar responses. OBJECTIVES: To thoroughly describe the development of fatigue during actual soccer match play and its recovery time course in terms of physiological, neuromuscular, technical, biochemical and perceptual responses, and (2) to determine similarities of recovery responses between actual competition (11 vs. 11) and match simulations. METHODS: A first screening phase consisted of a systematic search on PubMed (MEDLINE) and SportDiscus databases until March 2016. Inclusion criteria were: longitudinal study with soccer players; match or validated protocol; duration > 45 min; and published in English. RESULTS: A total of 77 eligible studies (n = 1105) were used to compute 1196 effect sizes (ES). Half-time assessments revealed small to large alterations in immunological parameters (e.g. leukocytes, ES = 1.9), a moderate decrement in insulin concentration (ES = - 0.9) and a small to moderate impairment in lower-limb muscle function (ES = - 0.5 to - 0.7) and physical performance measures (e.g. linear sprint, ES = - 0.3 to - 1.0). All the systematically analyzed fatigue-related markers were substantially altered at post-match. Hamstrings force production capacity (ES = - 0.7), physical performance (2-4%, ES = 0.3-0.5), creatine kinase (CK, ES = 0.4), well-being (ES = 0.2-0.4) and delayed onset muscle soreness (DOMS, ES = 0.6-1.3) remained substantially impaired at G + 72 h. Compared to simulation protocols, 11 vs. 11 match format (CK, ES = 1.8) induced a greater magnitude of change in muscle damage (i.e. CK, ES = 1.8 vs. 0.7), inflammatory (IL-6, ES = 2.6 vs. 1.1) and immunological markers and DOMS (ES = 1.5 vs. 0.7) than simulation protocols at post-assessments. Neuromuscular performances at post-match did not differ between protocols. CONCLUSION: While some parameters are fully recovered (e.g. hormonal and technical), our systematic review shows that a period of 72 h post-match play is not long enough to completely restore homeostatic balance (e.g. muscle damage, physical and well-being status). The extent of the recovery period post-soccer game cannot consist of a 'one size fits all approach'. Additionally, the 'real match' (11 vs. 11 format) likely induces greater magnitudes of perceptual (DOMS) and biochemical alterations (e.g. muscle damage), while neuromuscular alterations were essentially similar. Overall, coaches must adjust the structure and content of the training sessions during the 72-h post-match intervention to effectively manage the training load within this time-frame