The use of a functional test battery as a non-invasive method of fatigue assessment

Abstract

To assess whether a battery of performance markers, both individually and as group, would be sensitive to fatigue, a within group random cross-over design compared multiple variables during seated control and fatigue (repeated sprint cycling) conditions. Thirty-two physically active participants completed a neuromuscular fatigue questionnaire, Stroop task, postural sway, squat jump, countermovement jump, isometric mid-thigh pull and 10 s maximal sprint cycle (Sprintmax) before and after each condition (15 min, 1 h, 24 h and 48 h). In comparison to control, larger neuromuscular fatigue questionnaire total score decrements were observed 15 min (5.20 ± 4.6), 1 h (3.33 ± 3.9) and 24 h (1.83 ± 4.8) after cycling. Similarly, the fatigue condition elicited greater declines than control at 15 min and 1 h post in countermovement jump height (1.67 ± 1.90 cm and 1.04 ± 2.10 cm), flight time-contraction time ratio (0.03 ± 0.06 and 0.05 ± 0.11), and velocity (0.06 ± 0.07 m∙s-1 and 0.04 ± 0.08 m∙s-1). After fatigue, decrements were observed up to 48 h for average Sprintmax cadence (4-6 RPM), up to 24 h in peak Sprintmax cadence (2-5 RPM) and up to 1 h in average and peak Sprintmax power (45 ± 60 W and 58 ± 71 W). Modelling variables in a stepwise regression demonstrated that CMJ height explained 53.2% and 51.7% of 24 h and 48 h Sprintmax average power output. Based upon these data, the fatigue induced by repeated sprint cycling coincided with changes in the perception of fatigue and markers of performance during countermovement and squat jumps. Furthermore, multiple regression modelling revealed that a single variable (countermovement jump height) explained average power output.

Fig 1. Study protocol overview.

(A) Fatigue test battery testing (grey squares) with control protocol (circle) and fatigue intervention (triangle). (B) Fatigue intervention consisting of 4 sprint sets interspersed with 90 s active recovery (dashed square). (C) Sprint set breakdown consisting of 10 x 6 s sprints (crossed rectangle) with 30 s active recovery (dashed square).

Fig 2. Neuromuscular fatigue questionnaire results.

The mean (SD) neuromuscular fatigue questionnaire responses (n = 30) for the control (circles) and fatigue interventions (squares) from immediately prior (Pre) to 48 h post condition. *Significant (p < 0.05) difference between conditions at the identified time point using a Benjamini-Hochberg post hoc procedure.

Fig 3. Squat jump results.

The mean (SD) squat jump result (n = 31) for the control (circles) and fatigue interventions (squares) of (A) flight time to contraction time ratio (FT:CT) and (B) peak propulsive (concentric) velocity. Time points from immediately prior (Pre) to 48 h post condition. *Significant (p < 0.05) difference between conditions at the identified time point using a Benjamini-Hochberg post hoc procedure.

Fig 4. Counter movement jump results.

The mean (SD) countermovement jump result (n = 31) for the control (circles) and fatigue interventions (squares) of (A) jump height; (B) flight time to contraction time ratio (FT:CT) and (C) peak propulsive (concentric) velocity. Time points from immediately prior (Pre) to 48 h post condition. *Significant (p < 0.05) difference between conditions at the identified time point using a Benjamini-Hochberg post hoc procedure.

Fig 5. Sprint^max results.

The mean (SD) maximal cycling sprint (Sprint^max) result (n = 30) for the control (circles) and fatigue interventions (squares) of (A) sprint average cadence, (B) sprint peak cadence, (C) sprint average power and (D) sprint peak power variables. Time points from immediately prior (Pre) to 48 h post condition. *Significant (p < 0.05) difference between interventions at the identified time point using a Benjamini-Hochberg post hoc procedure.