ECSS Paris 2023: OP-AP32
INTRODUCTION: To optimize performance, testing and monitoring are vital for coaches and athletes to understand training adaptations. The critical power (CP) metric, highlighting the highest intensity for maintaining metabolic balance and the excess work capacity (W), stands out for its ease of use through non-invasive methods. Despite its growing popularity for setting training zones, the interchangeability of CP and W across different flat terrains like the athletic track, road, and trail is unclear. This study aims to examine the influence of flat running surfaces on CP and W values among highly trained trail runners, hypothesizing exchangeable values across surfaces. METHODS: Thirteen highly trained trail runners, injury-free and competing internationally, participated in the study. A repeated measures design examined the effect of different flat terrains on Critical Power (CP) and W. Participants underwent three testing sessions on road, track, and groomed trail. Each session included a 9- and 3-min run separated by a 30-min rest. CP and W were determined using a linear model. Participants refrained from vigorous activity 24 hours before each test. Testing conditions were consistent, including environmental factors and footwear. Warm-up included 10 minutes of low-to-moderate intensity running and dynamic exercises. The Borg CR-10 scale assessed perceived effort, and a Stryd power meter measured power output. RESULTS: The analysis using repeated measures ANOVA reveals no significant difference in power output across the 9-minute and 3-minute running intervals conducted on the different flat surfaces, with p-values of 0.387 and 0.624, respectively. In addition, critical power (CP) values, both in absolute terms (watts) and relative terms (w/kg), did not differ significantly across terrains (p = 0.541 and p = 0.583, respectively). Furthermore, the analysis showed no significant difference in W’ (p = 0.743). The perceived exertion, measured by the Borg CR-10 scale, was similarly reported to be consistent immediately after the completion of the 9-minute (p > 0.147) and the 3-minute (p > 0.066) running bouts on each terrain. CONCLUSION: This study is aimed at evaluating the influence of flat running surfaces (athletic track, road, and trail) on running CP and W’ in highly trained trail runners. The results revealed that the CP and W’ determined on the three different flat running surfaces are similar, showing no significant differences between the values. This offers coaches and athletes the opportunity to use any of these flat surfaces to complete a running CP test and extrapolate the value to training sessions to the two other flat surfaces here evaluated. Similarly, coaches and athletes may be confident when determining the W’ on any of the three flat surfaces here reported.
Read CV Diego Jaén-CarrilloECSS Paris 2023: OP-AP32
INTRODUCTION: Critical power (CP) and running critical speed (CS) represent pivotal markers in exercise physiology, distinguishing between heavy and severe-intensity domains and aiding in training prescription and performance prediction (1,2). Concurrently, the concept of durability, defined as the time and magnitude of physiological deterioration during prolonged exercise (3), has emerged as a key area of exploration in endurance sports. In this line, CP has been shown to decline following extended exercise during cycling (4). Furthermore, it has been demonstrated that this decline can be mitigated through interventions such as carbohydrate ingestion (5). However, the deterioration of CS following running exercise has not been researched yet, particularly in field conditions. This study aimed to investigate whether an hour of heavy-intensity running would induce a deterioration in CS and other parameters, utilizing global positioning system (GPS)-based assessments. METHODS: After familiarization, CS was measured in 7 trained runners using a three-minutes all-out test (3MT). On a subsequent visit, participants ran for one hour at 85% of CS, wearing a portable high-frequency GPS device. Following the fatiguing trial, participants performed another 3MT to obtain the CS under fatigue conditions and assess durability. RESULTS: The actual average speed sustained during the fatiguing task was 3.6 ± 0.4 m·s-1, corresponding to 78% of the CS and eliciting 85% of maximal heart rate. CS declined significantly by 5.8%. Additionally, D’, total running distance, maximal speed and time to reach maximal speed were also significantly reduced after the fatiguing task (p < 0.01). CONCLUSION: These results show that CS along with other performance parameters are impaired following one hour of heavy-intensity exercise. This highlights the importance of durability and suggests that performance in prolonged endurance exercise may not only be determined by initial levels of certain ‘key’ physiological factors but also by how these factors deteriorate during exercise. References: 1. Black MI, Jones AM, et al. Muscle metabolic and neuromuscular determinants of fatigue during cycling in different exercise intensity domains. J Appl Physiol. 2017;122(3):446-59. 2. Kolbe T, Dennis SC, Selley E, Noakes TD, Lambert MI. The relationship between critical power and running performance. J Sports Sci. 1995;13(3):265-9. 3. Maunder E, Seiler S, et al. The Importance of ‘Durability’ in the Physiological Profiling of Endurance Athletes. Sports Med. 2021;51(8):1619-28. 4. Clark IE, Vanhatalo A, Bailey SJ, et al. Effects of Two Hours of Heavy-Intensity Exercise on the Power-Duration Relationship. Med Sci Sports Exerc. 2018;50(8):1658-68. 5. Clark IE, Vanhatalo A, et al. Dynamics of the power-duration relationship during prolonged endurance exercise and influence of carbohydrate ingestion. J Appl Physiol Bethesda Md 1985. 2019;127(3):726-36.
Read CV Jaume Lloria-VarellaECSS Paris 2023: OP-AP32
INTRODUCTION: Critical intensity is an important fatigue threshold with considerable potential for enhancing performances or quality of life of individuals experiencing chronic diseases (1). Traditionally, critical velocity (Vc) is assessed from 3 to 5 tests-to-exhaustion, time-trials (TT) or all-out, making regular assessments of athletes or frail populations challenging. Recently, Bowen et al. (2) formalised a mathematical model that describes the evolution of maximal capacities at any time of severe exercises. This model, along with the Vc concept suggests that maximal velocity (Vmax) decreases when running above Vc and recover for intensity below Vc. Thus, performing a decreasing ramp starting above and finishing below Vc, Vmax is assumed to decrease and then rise again, the ramp value at switch point corresponding to Vc. Based on this idea, the Ramp Above Critical Level Endurance Test (RACLET) has been validated in cycling (3). The RACLET consists in a 5-min non-exhaustive test following a decreasing ramp velocity target during which ~3s sprints assess Vmax every 30s. This study aimed to test the reliability and validity of the RACLET during running. METHODS: 17 participants completed 4 sessions separated by 24h, starting with a 30-min standardised warmup. Session 1 included 2 identical RACLET separated by a 10-min rest, and during which participants running velocity was measured using GPS (GPexe, 18Hz). RACLET started at 65% of the initial maximal velocity (Vi) and gradually decreased to reach 3m/s at 5min. To maintain the target pace, participants followed a pacing bike that shifted to the side during sprints. Sessions 2 to 4 included randomised TT on 400, 1500 and 3000m. Vmax reached during each sprint of the RACLET or mean velocity performed during the TT allowed to fit the following equation: Vmax(t)=Vi–(1/Tau)*(int(V(t)-Vc)dt) where V is the target velocity and Tau is a time constant. Vc reliability was quantified using SEM and ICC between the 2 RACLET. Validity was assessed using systematic and random errors compared with the gold standard method (TT). RESULTS: Mean Vc was 13.5±2.1km/h on RACLET. This value is in line with data reported in the literature (4). Vc determined with RACLET showed good absolute (SEM=3.7%) and relative (ICC=0.95) reliability and presented a good concurrent validity with low systematic (0.1km/h; 1.3%) and random (0.7km/h; 5.6%) errors. Vc obtained from RACLET and TT were highly correlated (r=0.95, p<0.001). CONCLUSION: The RACLET is a valid and reliable method to assess Vc in running. This test has the advantage of being short, carried out in a single session and mainly submaximal (excluding short Vmax evaluations). The RACLET is interesting for research purposes to evaluate Vc (e.g. for experimental designs with numerous conditions) but also for follow-up monitoring requiring frequent reassessment of Vc, which was hitherto difficult to do. REFERENCES: Poole et al., MSSE, 2016 Bowen et al., JTB, 2023 Bowen et al., ECSS, 2023 Kramer et al., EJAP, 2020
Read CV Mylène VONDERSCHERECSS Paris 2023: OP-AP32