Objective Late-race deceleration is a common bottleneck in long-distance endurance events, where glucose homeostasis is considered a decisive physiological determinant of competitive success. This study aimed to provide empirical evidence to support optimized race-day fueling strategies for Chinese elite athletes.

Methods Twenty-six elite Chinese 20-km race walkers, including Olympic and World Championships champions, were continuously monitored for blood glucose, heart rate, segmental speeds, and pre-/post-race blood lactate. The race was divided into four 5-km segments (T1: 1～5 km, T2: 6～10 km, T3: 11–15 km, T4: 16～20 km). The data were multi-dimensional analyzed by using generalized estimating equations (GEE), correlation heatmaps, and rank-slope k models.

Results 1) All athletes demonstrated a “steady-decay-sprint” pacing pattern, with a significant speed decline during the final segment (T4) (P＜0.001). Stratified analyses indicated this decline was primarily driven by male athletes, whereas females showed no significant pace changes across the race. 2) Only 17% of athletes achieved negative splitting (late-race acceleration), yet 50% of those athletes achieved their season-best performance. 3) Race-time glucose levels consistently exhibited exercise-induced hyperglycemia (median 9.4 mmol/L) with a distinct inverted-U pattern: a progressive rise in the first half, peaking during T3, followed by a significant drop in T4 (P=0.002). 4) This variation exhibited significant sex differences, with both peak glucose and T4 glucose levels being significantly higher in female athletes compared to males (P＜0.05). Correlation analyses revealed that in females, mean race-time glucose not only significantly correlated with competition results (Ρ=−0.613, P＜0.05) but also explained 52.3% of late-race (T4) speed variability (R²=0.523). In males, peak blood glucose (ρ=−0.524, P＜0.05) and mean blood glucose at T3 (ρ=−0.579, P＜0.05) were significantly associated with speed stability coefficient of variation of speed at T4. 5) An individualized evaluation model based on the rank-slope k effectively quantified the match between glycemic stability and athletic capacity. This model identified 33% of the cohort as “high-potential” athletes, characterized by lower glycemic reactivity yet strong speed maintenance capability.

Conclusions In elite 20 km racewalking, the decline in blood glucose during the later stages of the race exhibits high temporal synchronization with the decrease in speed. The association between glucose metabolism and athletic performance demonstrates sex-specific differences, with superior blood glucose homeostasis emerging as a key characteristic for female athletes to maintain late-race pace.The rank-slope k can effectively assess the alignment between an athlete’s glucose metabolism and competitive capacity. This framework can assist coaches in analyzing the underlying causes of late-race pace decline, thereby facilitating targeted interventions, such as pre-emptive carbohydrate supplementation or the enhancement of sport-specific conditioning.