ECSS Paris 2023: OP-AP31
INTRODUCTION: In the realm of sports, the notion of tactics has been delineated by various researchers as the strategic maneuvers executed by athletes to adjust to dynamically shifting conditions during matches. The delicate equilibrium of competition between two players is disrupted as soon as one scores a point, inevitably prompting alterations in tactics, playing style, and the psychological disposition of the athletes [1]. Hence, the primary objective of this study was to formulate a tactical framework for wrestling matches aimed at predicting the likelihood of match outcomes based on specific scores, remaining time until the end of the match, and associated variables throughout the bout. METHODS: To achieve this, data on score, time, weight class, round of competition, and wrestling style were automatically annotated from 5280 bouts sourced from the international wrestling circuit. Subsequently, a multi-state Markov model was computed to ascertain the probabilities of match progression and outcome. Transition intensities were derived using the Nelson-Aalen estimator, while the Aalen-Johansen estimator facilitated the calculation of fight evolution probabilities at each moment. RESULTS: The developed model provides insights into the dynamics of score transitions during a match and enables the estimation of match outcomes based on current scores. All probabilities of score changes and match outcomes were computed for every feasible score differential and consolidated into a matrix. For instance, considering a 4-point disparity, irrespective of wrestling style, this advantage tends to steer the match towards victory (40%), a tendency that becomes more pronounced if the gap arises late in the match (90% in the final minute). CONCLUSION: This study presented a Markov chain-based approach to enhance comprehension of the tactical progression of wrestling matches. While the results show promise, there are avenues for several enhancements, many of which necessitate a more detailed dataset. Future endeavors will involve incorporating techniques associated with each scored point as well as the location on the combat surface. The current model is poised to advance towards a semi-Markovian model that is non-uniform over time [2], considering the duration spent in a state and parameterized through a priori testing of various distributions. [1] R. Rein et D. Memmert, « Big data and tactical analysis in elite soccer: future challenges and opportunities for sports science », Springerplus, vol. 5, no 1, p. 1410, août 2016, doi: 10.1186/s40064-016-3108-2. [2] A. Asanjarani, B. Liquet, et Y. Nazarathy, « Estimation of semi-Markov multi-state models: a comparison of the sojourn times and transition intensities approaches », The International Journal of Biostatistics, vol. 18, no 1, p. 243‑262, mai 2022, doi: 10.1515/ijb-2020-0083.
Read CV Issa MoussaECSS Paris 2023: OP-AP31
INTRODUCTION: Altitude training is a commonly used strategy to enhance endurance performance. With greater access to altitude centres, a greater number of athletes from a range of different sports have used altitude training. Given the importance of specificity in a training programme, it is important to tailor altitude training to the demands of each sport. Practices to using altitude training amongst combat sports such as judo remain largely unknown. Therefore, the aims of this study were threefold: to explore: 1) the practices to using altitude training in judo athletes, coaches, and practitioners (hereafter referred to as “performance staff”); 2) the perceptions of judokas and performance staff in relation to the use of altitude training; 3) the educational methods implemented by performance staff and judokas regarding altitude training. METHODS: 11 judokas and 9 performance staff completed an online questionnaire comprised of 5 sections: (1) informed consent; (2) participant information; (3) altitude practices; (4) education and understanding; (5) altitude perceptions. Closed questions were explored using frequency analysis and a 6-step thematic analysis was completed for open-ended questions. RESULTS: Judo athletes and performance staff primarily used altitude training to improve performance at sea-level (20%) and competition performance at sea-level (20%). Altitude training to improve competition performance at altitude was rare (60%). Using a normobaric chamber (10%) was the most common way of altitude training, with training conducted at moderate altitudes (2,100-2,600 m) were most frequently reported (15%). With training programmes being for 3-4 weeks (10%). Only 35% of respondents had received (judokas) or delivered (performance staff) education on altitude training. The main provider of education amongst judokas were sport scientists (30%) and the use of journal articles as the primary source of information (35%). Most respondents (55%) reported fitness enhancement (e.g. improved aerobic capacity) as the main benefit of altitude training and lifestyle barriers (e.g. cost) (45%) as the primary drawback. 30% of respondents agree that altitude training benefits judo performance and 25% believe it to be beneficial to improving fitness. CONCLUSION: Findings demonstrate altitude training is not currently common practice in judo although judokas and performance staff seem to perceive altitude training as beneficial to both fitness development and judo performance. Generally, altitude training is used by judokas and performance staff to improve sea-level performance rather than performance at altitude, which is likely to reflect where competition takes place. Few judokas had received education on altitude training. The present study is being extended to increase sample size to explore the generalizability of findings. Finally, some judokas and performance staff seem to perceive altitude training as beneficial to both fitness development and judo performance.
Read CV Joshua TillECSS Paris 2023: OP-AP31
INTRODUCTION: Live Low – Train High (LL-TH) models of hypoxia training have provided equivocal results when hypoxia exposure was limited to high-intensity aerobic training sessions [1-2]. A major issue is the reduction in the mechanical training load required to cope with the hypoxia-induced limitation in maximal aerobic power. Using the specific features of eccentric (ECC) cycling, namely its ability to achieve high mechanical power output despite limited metabolic demand [3], might be a promising strategy to maintain or enhance the mechanical training load in LL-TH interventions. This case study aimed to establish if combining high-intensity interval concentric (CON) and ECC cycling under hypoxia improves physiological determinant of judo performance in a well-trained female judo athlete. METHODS: A well-trained female judoka (21y, 1.70m, 69kg, national level, last two year weekly training volume: 10-15h) underwent 2 weekly normobaric hypoxic (3,000m) training sessions over a 6-wk period. Each training session required 5 repetitions of 3-min CON cycling at 100% of her hypoxic CON maximal aerobic power (MAP), separated by 3-min of active recovery in ECC cycling at 150% of her hypoxic CON MAP. Pre and post training assessments included body composition (DEXA scan), vastus lateralis thickness (VLT, echography), knee extensor maximal voluntary isometric contraction (MVC), maximal incremental cycling tests in normoxia and hypoxia as well as a repeated cycling sprint ability test (RSA, 10s sprint/20s passive recovery). All cycling tests were performed in CON mode. Data are presented as single individual post vs pre relative changes. RESULTS: All training sessions (exercise CON power=170W; recovery ECC power=260W) were completed with a hypoxic exposure of 60min/wk. Fat mass decreased after training (-9.5%) whereas fat-free mass and VLT increased (2.5 and 7.2% respectively). In hypoxia, the power output associated to maximal oxygen uptake (pVO2max, +11.1%) as well as with the second (pSV2, +20%) and the first ventilatory thresholds (pSV1, +20%) improved after training. In normoxia, greater values were also observed after training for pVO2max (+13.7%), pSV2 (+12.5%) and pSV1 (+25%). MVC did not change (-1.8%) but absolute CON maximal sprint power improved (8.5%). During the RSA test, the number of sprints performed before exhaustion increased (22%) while the peak power output developed during each sprint improved (12%). CONCLUSION: These data demonstrate the feasibility of a new LL-TH design combining high-intensity CON and ECC cycling in moderate hypoxia. The results suggest beneficial morphological, cardiorespiratory and neuromuscular adaptations with the potential to improve judo performance in well-trained to elite judo athletes. Chronic studies should further explore this new LL-TH strategy to confirm this case report. 1. Dufour et al. J Appl Physiol. 2006 2. Faiss et al. Brit J Sports Med. 2013 3. Isner-Horobeti et al. Sport Med. 2013 This study was supported by a grant ANR-20-STHP-0002
Read CV Fabrice FavretECSS Paris 2023: OP-AP31