The use of performance assessments and force-time curve analysis to measure mental and physical fatigue

Author Identifier

Steven Hughes

Date of Award


Document Type



Edith Cowan University

Degree Name

Doctor of Philosophy


School of Medical and Health Sciences

First Supervisor

Sophia Nimphius

Second Supervisor

Gregory Haff

Third Supervisor

Dale Wilson Chapman

Fourth Supervisor

John Warmenhoven


As management of fatigue and recovery is a key objective of modern sport, athlete monitoring is now commonplace. With assessments such as perceptual questionnaires, countermovement jumps (CMJ), squat jumps (SJ), isometric mid-thigh pulls (IMTP), and postural sway having been used with varied success, the use of emerging analysis techniques may improve sensitivity. For example, while vertical jump assessment traditionally employs analysis of discrete individual metrics calculated from a location on the force-time curve, complete force-time curve analysis may provide greater sensitivity by retaining information commonly discarded in discrete analysis. Furthermore, with mental fatigue reportedly impairing cognitive and physical performance, identifying an objective, practical assessment of mental fatigue would provide practitioners with a more comprehensive assessment of athlete fatigue.

Study 1 investigated whether several performance assessments (perceptual questionnaire, cognitive assessment, postural sway, CMJ, SJ, IMTP) could model fatigue, improving assessment over stand-alone analysis at multiple time points. These findings supported the use of perceptual questionnaires, CMJ, SJ and maximal cycling sprints, with perceptual questionnaires and cycling sprints demonstrating impairment at 24 and 48 hr. However, when attempting to model 24 and 48 hr power outputs from metrics at earlier time points, only CMJ height explained power output.

Study 2 sought to determine whether a complete time-series analysis of biomechanical data through Statistical Parametric Mapping (SPM) could better detect fatigue than traditional discrete methods. Two-way repeated measures ANOVA was performed on relative force-time curves (SPM analysis) and peak relative force (discrete analysis) taken from the same data set with SPM analysis alone detecting fatigue.

Study 3 assessed the ability of four cognitive performance assessments and a time-series analysis of CMJ force through functional principal components analysis (fPCA), to objectively measure mental fatigue after 60 min of a mentally fatiguing task. Despite post hoc testing not reaching significance, a significant interaction effect in reaction task linear mixed model analysis (LMM) and medium effect sizes, suggested that the reaction task alone was likely impaired by 60 min of cognitive tasks. Furthermore, time-series analysis explained 95.8% of the total variation in force-time curves, with LMM analysis reporting a significant difference after mental fatigue.

Utilising performance assessment tasks, Study 4 explored mental and physical fatigue responses across four conditions consisting of varying distributions of physical and cognitive loads: futsal (physical+cognitive), workload-matched treadmill session (physical), timematched soccer video gameplay (cognitive) and a control. The findings indicate that perceptual questionnaires and SJ were impaired by physical workloads of match play and treadmill sessions, while CMJ was impaired by match play but not treadmill fatigue. No significant differences were observed in IMTP or reaction tasks in any condition. This research suggests that reaction tasks were ineffective at measuring mental fatigue after sporting competition and video gameplay.

This thesis supports perceptual feedback and jump testing for subjective and objective assessment of both physical and mental fatigue. Furthermore, discrete and time-series jump analysis can be used to assess specific performance outcomes or execution of movements. Finally, the cognitive reaction task likely provides an objective measure of severe mental fatigue with the brevity of the aforementioned assessments promoting practicality in sports.

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