Author(s): FUK, A., CABBOI, L., VILLANOVA, S., QUAGLIAROTTI, C., FILIPAS, L., GALLO, G., GRAMAZIO, A., DELLO STRITTO, E., BAZZUCCHI, I., CONTI, A., LAMBERTS, R.P., PIACENTINI, M.F., Institution: UNIVERSITY OF ROME, FORO ITALICO, Country: ITALY, Abstract-ID: 2067

INTRODUCTION:
Performance decline over time has been reported in cycling [1] and running [2]. However, whether and how this deterioration is transferred across disciplines (e.g., from cycling to running) in sports such as triathlon remains unknown. Therefore, the aim of this study was to determine the effect of a prolonged cycling protocol on paced and all-out running performance.
METHODS:
Eleven trained male triathletes (VO₂max 61.7±4.9 ml/kg/min) completed a 45-min paced treadmill run at the first lactate threshold (LT1) speed, followed by a 45-min all-out outdoor run, on two separate occasions. One was performed in fresh (FRE) condition, while the other, referred to as the ‘fatigued’ (FAT) condition, was performed after a cycling bout of 150 min at 90% of the LT1 power. Carbohydrate intake was regulated at 60 g/h. VO₂REL, heart rate (HR) and running economy (RE) were measured during the treadmill running test. Running speed, HR and completed distance were captured during the outdoor session. Changes over time were examined by comparing data from each third of the 45-minute running sessions (T1, T2, and T3). A two-way repeated-measures ANOVA was used to analyze condition, time, and interaction effects, while a Tukey post-hoc test was used when significance was found. A t-test was used to compare overall running speed and completed distance during the outdoor run. Significance was accepted at p<.05.
RESULTS:
Analyses of paced treadmill running session showed interaction effects for all performance parameters (p<.04), indicating that VO₂REL (4.8–5.8%,p≤.01), HR (1.5–2.2%,p≤.05) were higher and RE (4.8–5.8%,p≤.02) was poorer in the FAT compared to the FRE condition at all time points. In addition, a deterioration of these parameters was seen over time, which occurred earlier in the FAT (T1–T2: 1.5–1.9%,p<.01; T1–T3: 2.9–4.1%,p<.001) than in the FRE condition (T1–T3: 2.1–3.7%,p<.01).
Analysis of the outdoor run showed that total covered distance (11.5 vs. 11.0 km,p<.001) and, consequently, overall running speed (15.3 vs. 14.6 km/h,p<.001) were lower in the FAT condition. In line with this, running speed in FAT was slower at all the time intervals (3.4–4.0%,p≤.03), while no change in speed over time was observed (p=0.68). HR was similar between the FRE and FAT during the outdoor run and did not change over time (p>0.05).
CONCLUSION:
This is the first study to show that prolonged cycling significantly impairs subsequent paced running parameters and self-paced running performance. While differences in all performance parameters were observed between the FAT and FRE conditions, changes over time were observed only during the paced running session. This finding suggests that, during the self-paced session, runners from the start follow an adapted pacing strategy. These findings provide valuable insights for coaches and athletes that may assist in optimizing pacing and training strategies in multidisciplinary sports.
REFERENCES:
1. Stevenson J, EJAP 2022:122:2673-82
2. Zanini M, SJMSS 2025:35:e7006