Fatigue Effects on Peak Plantar Pressure and Bilateral Symmetry during Gait at Various Speeds

Fatigue-related changes in gait biomechanics, specifically plantar pressures, are well documented in the general population. However, research is generally confined to unilateral measures across a limited range of speeds, while changes in more well-trained populations remain largely unknown. Therefore, we sought to assess the impact of fatigue on bilateral peak plantar pressure (PP) and plantar pressure symmetry angle (SA) in well-trained runners across a range of speeds. Data from 16 (females, n = 9) well-trained runners were collected using in-sole pressure sensors pre- and post-fatigue at the following speeds: walking (1.3 m/s), jogging (2.7 m/s), running (3.3 m/s), and sprinting (4.5 m/s). Pre-fatigue PP significantly increased from walking to jogging (p < 0.001) and from jogging to running (p < 0.005) with no difference between running and sprinting (p > 0.05). Post-fatigue PP for walking was less than jogging (p < 0.002), running (p < 0.001), and sprinting (p < 0.001), with no other significant differences (p > 0.05). Post-fatigue PP was significantly greater when compared to pre-fatigue PP at all speeds (p < 0.001 for all). Though SA was not significantly different pre- to post-fatigue across speeds (p's > 0.05) at the cohort level, noteworthy changes were observed at the individual level. Overall, fatigue effects are present at all running speeds but isolating these effects to a single side (left or right) may be inadequate.