RESUMO
BACKGROUND: A ketogenic diet (KD) reduces daily carbohydrates (CHOs) ingestion by replacing most calories with fat. KD is of increasing interest among athletes because it may increase their maximal oxygen uptake (VO2max), the principal performance limitation at high-altitudes (1500-3500 m). We examined the tolerance of a 4-week isocaloric KD (ICKD) under simulated hypoxia and the possibility of evaluating ICKD performance benefits with a maximal graded exercise bike test under hypoxia and collected data on the effect of the diet on performance markers and arterial blood gases. METHODS: In a randomised single-blind cross-over model, 6 recreational mountaineers (age 24-44 years) completed a 4-week ICKD followed or preceded by a 4-week usual mixed Western-style diet (UD). Performance parameters (VO2max, lactate threshold [LT], peak power [Ppeak]) and arterial blood gases (PaO2, PaCO2, pH, HCO3-) were measured at baseline under two conditions (normoxia and hypoxia) as well as after a 4-week UD and 4-week ICKD under the hypoxic condition. RESULTS: We analysed data for all 6 participants (BMI 19.9-24.6 kg m-2). Mean VO2max in the normoxic condition was 44.6 ml kg-1 min-1. Hypoxia led to decreased performance in all participants. With the ICKD diet, median values for PaO2 decreased by - 14.5% and VO2max by + 7.3% and Ppeak by + 4.7%. CONCLUSION: All participants except one could complete the ICKD. VO2max improved with the ICKD under the hypoxia condition. Therefore, an ICKD is an interesting alternative to CHOs dependency for endurance performance at high-altitudes, including high-altitude training and high-altitude races. Nevertheless, decreased PaO2 with ICKD remains a significant limitation in very-high to extreme altitudes (> 3500 m). Trial registration Clinical trial registration Nr. NCT05603689 (Clinicaltrials.gov). Ethics approval CER-VD, trial Nr. 2020-00427, registered 18.08.2020-prospectively registered.
RESUMO
Objectives: This project aims to assess opinions, attitudes, knowledge, beliefs, practices and perceived barriers and facilitators of injury prevention (IP) strategies in Swiss basketball teams. Methods: An online survey was sent to athletes, coaches and medical staff of the three best basketball leagues in Switzerland. The survey was subdivided in four sections: (1) characteristic of participants, (2) knowledge, opinions, attitudes and beliefs, (3) practices and (4) barriers and facilitators. Results: Among 105 persons (n=45 female, n=60 male) who answered the survey, more than 60% (n=68) considered the risk of injury for basketball athletes as being high to very high. The ankle, knee and the hand were considered as being the most at risk. More than 80% of participants considered that recovery, training load and the warm-up quality were very important factors for IP. More than 90% of participants considered IP as either important or very important with 53 (50.5%) of the participants indicating using exercise-based IP in their clubs. Athletes and coaches' motivation and compliance were judged as either important or very important for successful IP implementation by more than 80% of participants, with the coach being reported as the most influential person. Environmental barriers towards human or infrastructural resources were also reported as factors influencing IP strategies, namely by female participants. Conclusion: Good knowledge and positive attitude towards IP were reported by participants, but exercise-based IP strategies lack implementation. The coach was considered as the most influential person and was reported with the athletes as playing an important role towards successful implementation.
