Author(s): BIRDSEY, L.P., DOSSANTOS, T.1, EVANS, D.1, RUNACRES, A.1, WESTON, M.1,2, FIELD, A.1, Institution: THE UNIVERSITY OF EDINBURGH, Country: UNITED KINGDOM, Abstract-ID: 830

INTRODUCTION:
To reach the final of high-standard middle-distance running events, athletes must perform two rounds of competition separated by ~24h. As some athletes slow in the final [1] it is unclear as to why performance changes between rounds. Our aim therefore was to examine the impact of successive 1500 m time-trials on running performance, physiological, metabolic, neuromuscular, and perceptual responses.
METHODS:
Using a within-subjects design, twelve national-standard (10 male, 2 female, mean age ± SD: 27 ± 7 years, mass: 66 ± 8 kg, height: 1.8 ± 0.1 m, season’s best 1500 m time: 244.1 ± 18.8 s) middle-distance specialists completed a familiarisation 1500 m time trial (260.6 ± 21.3 s) followed by two 1500 m time-trials, separated by 24 h (during which time refrained from exercise or specific recovery practices), on a motorised treadmill (Gaitway 3D, h/p/cosmos sports and medical GmbH, Germany). Wellbeing (mood, fatigue, confidence, soreness, motivation) and neuromuscular performance, assessed via the countermovement jump (CMJ) using a portable force platform (HD Gen4, Hawkin Dynamics, USA), were measured prior to both time-trials. Respiratory gases, measured continuously (Vyntus CPX Metabolic Cart, Vyaire Medical Inc., USA), and session and differential ratings of perceived exertion (RPE, CR100®) confirmed no between-trial differences during a standardised 12.5-min warm up. During the time-trials, speed was controlled by athlete’s treadmill position (i.e., moving forwards to increase speed). Respiratory gases were measured continuously, and session (sRPE) and differential RPE (breathlessness [RPE-B], leg muscle exertion [RPE-L]) collected two min post. Blood lactate concentration (Biosen C-line, EKF Diagnostics, Germany) was measured post-exercise until a peak was obtained. All variables were log transformed before analysis with mixed linear models (fixed effect = trial, random intercept = athlete) with effect uncertainty expressed as 95% confidence intervals (95%CI).
RESULTS:
Pre time-trial CMJ was consistent between days (trial 1: 33 ± 5 cm, trial 2: 33 ± 5 cm, effect -0.1%: 95%CI -3.0% to 3.0%), whereas between-day effects in wellbeing were inconsistent and imprecise (range -4%;-17%, 10% [motivation] to 24%; -12%, 74% [mood]). Running performance (260.6 ± 21.3 s, 259.1 ± 22.6 s, -0.6%; -1.6%, 0.3%), mean V̇O2 (55.8 ± 3.9 ml·kg-1·min-1, 56.2 ± 4.2 ml·kg-1·min-1, 0.2%; -1.4%, 1.8%), heart rate (175 ± 7 b·min-1, 176 ± 6 b·min-1, -0.6%; -1.0%, -0.2%) and peak blood lactate (14.9 ± 2.3mM, 14.9 ± 1.8 mM, 0.8%; -0.6% to 8.1%) were consistent between trials. For RPE, effects were larger but with substantial imprecision (range 3.2%; -1.8%, 8.4% [sRPE] to 7.8%; -1.0%, 17.3% [dRPE-B]).
CONCLUSION:
National-standard middle-distance runners can maintain maximal 1500 m running performance on successive days. Further investigations of track-based competitions are required to fully understand the effects of successive day running performance.

[1] Hanley and Hettinga (2018)