Deviation from goal pace, body temperature and body mass loss as predictors of road race performance

Objectives The purpose of this study was to examine the relationship between pacing, gastrointestinal temperature (T_GI), and percent body mass loss (%BML) on relative race performance during a warm weather 11.3 km road race. Design Observational study of a sample of active runners competing in the 2014 Falmouth Road Race. Methods Participants ingested a T_GI pill and donned a GPS enabled watch with heart rate monitoring capabilities prior to the start of the race. Percent off predicted pace (%_OFF) was calculated for seven segments of the race. Separate linear regression analyses were used to assess the relationship between pace, T_​GI, and %BML on relative race performance. One-way ANOVA was used to analyse post race T_GI (≥40 °C vs <40 °C) on pace and %_OFF. Results Larger %BML was associated with faster finish times (R² = 0.19, p = 0.018), faster average pace (R² = 0.29, p = 0.012), and a greater %_OFF (R² = 0.15, p = 0.033). %_OFF during the first mile (1.61 km) significantly predicted overall finish time (R² = 0.64, p < 0.001) while %_OFF during the second mile (3.22 km) (R² change = 0.18, p < 0.001) further added to the model (R² = 0.82, p < 0.001). Body temperature (pre race T_GI and post race T_GI) was not predictive of overall finish time (p > 0.05). There was a trend in a slower pace (p = 0.055) and greater %_OFF (p = 0.056) in runners finishing the race with a T_GI > 40 °C. Conclusions Overall, finish time was influenced by greater variations in pace during the first two miles of the race. In addition, runners who minimized fluid losses and had lower T_GI were associated with meeting self-predicted goals.