A pragmatic approach to resolving technological unfairness: The case of Nike’s Vaporfly & Alphafly running footwear

Background Technology is often introduced into sport to facilitate it or to improve human performance within it. On occasion, some forms of novel technology require regulation or prevention entirely to ensure that a sport remains fair and accessible. Recently, the Nike Vaporfly and Alphafly shoes have received some concerns over their appropriateness for use in competitive distance running. Methods This paper evaluates the use of these shoes against an existing framework for sports technology discourse and adopts a pragmatic approach to attempt to resolve them. Results It is proposed that the three concerns regarding cost, access and coercion cannot be ruled out but likely remain short term issues. As a result, it is proposed that these running shoes are acceptable forms of technology but that ongoing vigilance will be required as such technologies develop further in the future. Conclusions The Nike Vaporfly/Alphafly shoes do push the perceived acceptability of running shoes to the limits of the current sports regulations. However, the alleged gains have not manifested themselves to a level that could be considered excessive when reviewing historical performances or when evaluated against a set of well-cited criteria. The sport will need to adopt a stance of ongoing vigilance as such technologies continue to develop or be optimised in the future

Beta-2 agonists and exercise performance in humans

Etat des connaissances concernant les effets ergogéniques des bêta-2 agonistes (terbutaline, bambutérol, salmétérol, formotérol). 'Si les études conduites suite à des inhalations de bêta-2 agonistes à dose thérapeutique ne mettent pas en évidence d'amélioration de la performance sportive (de faibles doses administrées n'entraînant pas de passage systémique significatif) la quasi-totalité des étude conduites après administration orale aiguë et de courte durée semble montrer une amélioration de la performance sportive, quelle que soit l'intensité de l'exercice effectué'

Modelling the transfers of training effects on performance in elite triathletes

Effets de 40 semaines d'entrainement en course, natation et cyclisme sur les performances en course, natation et cyclisme chez quatre triathlètes d'élite. La natation est une épreuve très spécifique en triathlon, qui ne bénéficie pas des entraînements de course et de cyclisme et dont l'entraînement n'améliore pas les performances de cyclisme et course de fond. Par contre on observe un transfert d'entrainement en course et cyclisme

Modeling the Responses to Resistance Training in an Animal Experiment Study

International audienceThe aim of the present study was to test whether systems models of training effects on performance in athletes can be used to explore the responses to resistance training in rats. 11 Wistar Han rats (277 ± 15 g) underwent 4 weeks of resistance training consisting in climbing a ladder with progressive loads. Training amount and performance were computed from total work and mean power during each training session. Three systems models relating performance to cumulated training bouts have been tested: (i) with a single component for adaptation to training, (ii) with two components to distinguish the adaptation and fatigue produced by exercise bouts, and (iii) with an additional component to account for training-related changes in exercise-induced fatigue. Model parameters were fitted using a mixed-effects modeling approach. The model with two components was found to be the most suitable to analyze the training responses (í µí±… 2 = 0.53; í µí±ƒ < 0.001). In conclusion, the accuracy in quantifying training loads and performance in a rodent experiment makes it possible to model the responses to resistance training. This modeling in rodents could be used in future studies in combination with biological tools for enhancing our understanding of the adaptive processes that occur during physical training

Chronic clenbuterol treatment compromises force production without directly altering skeletal muscle contractile machinery

International audienceClenbuterol is a β2-adrenergic receptor agonist known to induce skeletal muscle hypertrophy and a slow-to-fast phenotypic shift. The aim of the present study was to test the effects of chronic clenbuterol treatment on contractile efficiency and explore the underlying mechanisms, i.e. the muscle contractile machinery and calcium-handling ability. Forty-three 6-week-old male Wistar rats were randomly allocated to one of six groups that were treated with either subcutaneous equimolar doses of clenbuterol (4 mg kg−1 day−1) or saline solution for 9, 14 or 21 days. In addition to the muscle hypertrophy, although an 89% increase in absolute maximal tetanic force (Po) was noted, specific maximal tetanic force (sPo) was unchanged or even depressed in the slow twitch muscle of the clenbuterol-treated rats (P < 0.05). The fit of muscle contraction and relaxation force kinetics indicated that clenbuterol treatment significantly reduced the rate constant of force development and the slow and fast rate constants of relaxation in extensor digitorum longus muscle (P < 0.05), and only the fast rate constant of relaxation in soleus muscle (P < 0.05). Myofibrillar ATPase activity increased in both relaxed and activated conditions in soleus (P < 0.001), suggesting that the depressed specific tension was not due to the myosin head alteration itself. Moreover, action potential-elicited Ca2+ transients in flexor digitorum brevis fibres (fast twitch fibres) from clenbuterol-treated animals demonstrated decreased amplitude after 14 days (−19%, P < 0.01) and 21 days (−25%, P < 0.01). In conclusion, we showed that chronic clenbuterol treatment reduces contractile efficiency, with altered contraction and relaxation kinetics, but without directly altering the contractile machinery. Lower Ca2+ release during contraction could partially explain these deleterious effects

Effects of hypoxic interval training on cycling performance

Belle Roels, Grégoire P. Millet, Christophe J. L. Marcoux, Olivier Coste, David J. Bentley, and Robin B. Canda