The effects of running a 12-km race on neuromuscular performance measures in recreationally competitive runners

Abstract

Background The number of individuals participating in organised races is increasing, with few studies undertaken in ecologically-valid settings. Running involves cyclical movements and activation of lower-extremity muscles, with fatigue and foot-strike pattern proposed as factors contributing to running-related injuries.

Research question Our aim was to investigate the effects of running a 12-km race on plantar pressure distribution, postural balance, foot-strike pattern, and plantar-flexion strength. A secondary aim was to compare actual versus anticipated race finishing times and foot-strike patterns.

Methods Twenty-four recreationally competitive runners (15 males, 9 females) completed the following tests immediately before and after a 12-km race: (1) plantar pressure distribution in self-selected bilateral stance; (2) 30-seconds eyes-closed feet-together postural balance; (3) running foot-strike angle; and (4) peak plantar-flexion isometric force. In-race foot-strike angle and patterns were also assessed at 3 and 10 km.

Results Post-race left and right foot plantar pressure distribution, postural balance, and plantar-flexion force measures significantly differed from pre-race measures. These changes were associated with small to large standardised effects (absolute ES: 0.42 to 0.94). On average, the relative pressure under the left foot decreased by 3.2 ± 5.0%; the centre of pressure path length and area of the 95th percentile ellipse from the balance test increased by 5.7 ± 8.9 cm and 18.2 ± 21.3 cm2; and peak plantar-flexion isometric force decreased by 0.23 ± 0.28 times body weight. Participants predicted their finishing times relatively well, but not their foot-strike patterns. No meaningful change in foot-strike angle or pattern was observed pre- to post-race, or between 3 and 10 km.

Significance Running a 12-km race influenced neuromuscular measures, confirming racing-induced fatigue in our recreationally competitive runners. However, these alterations did not lead to observable changes in foot-strike pattern, indicating that this measure might not be appropriate for quantifying fatigue in recreationally competitive runners.