ECSS Paris 2023: OP-AP09
INTRODUCTION: Alterations in exercise performance follow the fluctuations in training characteristics in a complex and dynamic way. The aim of this study was to make a step towards a better determination of whether the different fluctuations in training velocities of short continuous or high-intensity interval running training are reflected in the adaptations achieved during repeated maximal and submaximal tests. METHODS: Two groups of 9 and 10 recreational runners took part in a period of 20 training sessions in 5 weeks, consisting of: 2000 m runs (CR) or 10x200 m high-intensity interval training with 2-minute walking recoveries (HIIT). The training period was divided into phases based on the fluctuations in running velocities according to individual daily performance. Each training phase was characterised by its initial running velocity, the slope coefficient of the linear fit of the time course of the running velocities and the average sum of squared residuals calculated as the differences between the values from the linear fit and the actual running velocities. Adaptations were determined using the velocities of the maximal 2000 m trials (v2000) before and after the training period and by submaximal 2x1000 m tests on the treadmill in each training phase, at the same velocity as the first 2000 m trial. During these tests, the gas exchange and the acid-base characteristics of the blood were measured. Repeated comparisons between the measured data for each phase and training method were analysed using repeated measures ANOVA or paired t-test. Both were set to p<0.05. RESULTS: The velocities of both training methods showed two phases, which were separated in CR and HIIT after about 10 training sessions. CR running velocity increased by 8% during the training period (F=16.672; p>0.001, power=0.998). Differently, HIIT running velocity increased by 6% only in the first phase (F=11.023; p>0.01; power=0.972) and remained stable until the end. CR increased maximal performance estimated by v2000 by 3% (p=0.04, power=0.52), while HIIT increased v2000 by 4% (p=0.003, power=0.909). During the submaximal 2x1000 m test, CR training lowered [LA] by approximately 21% (F=7.717; p=0.005; power=0.836), increased blood pH by 4% (F=3.781, p=0.045, power=0.462) and lowered Vo2 by approximately 6% (F=7.532; p=0.005; power=0.85). HIIT had no effect on [LA] or pH, but decreased submaximal Vo2 by 5% (F=3.612; p=0.039; power=0.474), but only in the first phase. CONCLUSION: Both training methods influenced performance and other adaptations in different phases, which requires a more time sensitive testing design in the future. The decreased [LA] and increased blood pH during the submaximal test as an effect of the CR method could indicate effects on lactate metabolism, while the decrease in Vo2 with both methods could indicate possible effects on running economy, but not with both methods simultaneously.
Read CV Anton UsajECSS Paris 2023: OP-AP09
INTRODUCTION: Studies assessing sports clothing and its ability to maximise thermoregulation, comfort, and performance have used a variety of exercise protocols and environmental conditions. This has led to much conjecture surrounding the ability for sports clothing to keep wearers cool and comfortable during exercise in the heat. This study aimed to develop a testing protocol combining fixed-rate and self-paced exercise for the practical assessment of sports clothing, evaluate its repeatability, and confirm the level of thermo-physiological and perceptual strain induced. METHODS: Eleven recreationally trained male runners (mean ± SD, age: 26.8 ± 5.6 years; VO2max 59.2 ± 5.1 mL/kg/min; training volume 70.0 ± 26.6 km/wk) each completed two experimental trials in a climate chamber (temperature: 30.3 ± 0.2oC; relative humidity: 67.6 ± 1.6%). Each trial included a 30-minute fixed-rate run (FRR) on a motorised treadmill at 65% VO2max followed by a 5 km time trial (TT) on a non-motorised treadmill. Oxygen consumption, heart rate (HR), core temperature (Tcore), skin temperature, sweat loss, physiological strain index (PSI), rate of perceived exertion (RPE), and thermal sensation (TS) were monitored during the FRR. Duration and distance were recorded following the TT. A repeated-measures ANOVA was used to determine significant differences throughout the FRR. Relative reliability of TT distance and duration was determined using intra-class correlation coefficients (ICC) and 95% confidence intervals. Absolute reliability was determined using within-participant coefficient of variation (CV). Sufficient strain was achieved when participants reached 4 of the following 5 criteria during the FRR: ≥ 1.2oC increase in Tcore compared to rest; HR ≥77% of HRmax; PSI ≥7/10; RPE ≥15/20; TS of -3 indicating a ‘hot’ sensation. RESULTS: No significant differences were observed between experimental trials for any thermal, physiological, or perceptual variables during the FRR (p>0.05). High relative reliability was confirmed for TT duration (ICC=0.98, 95% CI: 0.94, 0.99, p<0.001). Moderate relative reliability was confirmed for TT distance (ICC=0.95, 95% CI: 0.83, 0.99, p<0.001). Sufficient absolute reliability was achieved for TT duration (CV=1.1 ± 1.1%) but not for TT distance (CV=2.1 ± 1.6%). Of the 22 experimental trials completed, 17 induced sufficient thermo-physiological and perceptual strain. CONCLUSION: This study confirmed the reliability and sensitivity of a novel protocol to evaluate thermal, physiological, perceptual, and performance-based outcomes during exercise in hot and humid conditions. The results verified the suitability of the protocol to induce sufficient strain in recreationally trained runners. This research provides a platform for coaches, athletes, and researchers to apply and adjust evidence-based guidelines when evaluating the interaction between clothing, athletic performance, and the heat.
Read CV Samantha HoffmannECSS Paris 2023: OP-AP09
INTRODUCTION: Speed during incremental track tests identifying physiological performance determinants in distance runners is typically set by matching sound signals and visual marks in the track (1). However, it requires from the subject being tested constant pace adjustments and overcoming the air resistance derived from speed and variable wind. Recent approaches include the use of a cyclist setting the pace in front of the runner to provide more reliable test outcomes without the interferences associated to the cost of the decision-making process involved in self-pacing and the absence of the drafting effect (i.e., reduction in air resistance derived from positioning just behind another athlete or cyclist) (2). Therefore, the purpose of this study was to compare physiological performance determinants as well as the power exerted by runners, derived from an incremental track test in the presence and absence of drafting. METHODS: A randomised, counter-balanced, crossover experimental design was performed. An incremental track test was performed twice by 20 male amateur and highly-trained distance runners (37 ± 11 years; 68.8 ± 6.9 kg; VO2max = 49.1 ± 9.0 ml/kg/min) in the presence and absence of drafting. This test followed the University of Montreal protocol, characterized by an incremental speed to exhaustion increasing 0.5 km/h every minute. Runners wore a backpack with a portable gas analyser (Metamax 3B, Cortex, Germany) to determine speeds associated to both ventilatory thresholds (VTs), VO2max and maximal aerobic speed (MAS), a heart rate (HR) sensor (H10, Polar, Finland) to measure HRs associated to both VTs, and a potentiometer (Strydwind new, Boulder, USA) on the right shoe to measure running power associated to both VTs. For the drafting condition, runners were positioned directly behind a cyclist who set the pace, while in the non-drafting condition, runners performed the test while adjusting the speed to sound signals and visual marks in the track. A related-sample Students t-test was used to compare physiological performance determinants derived from each condition. RESULTS: MAS was significantly higher in the drafting vs non-drafting test (p = 0.020; d = 0.036), while no other statistically significant differences were found in the rest of performance determinants (p > 0.050). CONCLUSION: Track incremental running tests may also be drafted by a cyclist whereby their outcomes could not be affected by external and internal factors such as pacing ability and drafting absence. However, the MAS obtained may be faster than that measured without drafting. REFERENCES: 1. Casado et al. Maximum aerobic speed, maximum oxygen consumption, and running spatiotemporal parameters during an incremental test among middle- and long-distance runners and endurance non-running athletes, PeerJ, 2022. 10:e14035. 2. Casado et al. Performance and Psychophysiological Effects of Light-Guided Pacing During a 5000-m Run. International Journal of Sports Physiology and Performance, 2024. 20(2): p. 1-7.
Read CV Arturo CasadoECSS Paris 2023: OP-AP09