ABSTRACT
PURPOSE: Fran is one of the most popular CrossFit benchmark workouts used to control CrossFitters' improvements. Detailed physiological characterization of Fran is needed for a more specific evaluation of CrossFitters' training performance improvements. The aim of the study was to analyze the oxygen uptake (VËO2) kinetics and characterize the energy system contributions and the degree of postexercise fatigue of the unbroken Fran. METHODS: Twenty trained CrossFitters performed Fran at maximal exertion. VËO2 and heart-rate kinetics were assessed at baseline and during and post-Fran. Blood lactate and glucose concentrations and muscular fatigue were measured at baseline and in the recovery period. RESULTS: A marked increase in VËO2 kinetics was observed at the beginning of Fran, remaining elevated until the end (VËO2peak: 49.2 [3.7] mL·kg-1·min-1, VËO2 amplitude: 35.8 [5.2] mL·kg-1·min-1, time delay: 4.7 [2.5] s and time constant: 23.7 [11.1] s; mean [SD]). Aerobic, anaerobic lactic, and alactic pathways accounted for 62% (4%), 26% (4%), and 12% (2%) of energy contribution. Reduction in muscle function in jumping ability (jump height: 8% [6%], peak force: 6% [4%], and maximum velocity: 4% [2%]) and plank prone test (46% [20%]) was observed in the recovery period. CONCLUSIONS: The Fran unbroken workout is a high-intensity effort associated with an elevated metabolic response. This pattern of energy response highlights the primary contribution of aerobic energy metabolism, even during short and very intense CrossFit workouts, and that recovery can take >24 hours due to cumulative fatigue.
Subject(s)
Fatigue , Oxygen Consumption , Humans , Oxygen Consumption/physiology , Muscle Fatigue/physiology , Oxygen , MusclesABSTRACT
Our purpose was to characterize the oxygen uptake kinetics (VO2), energy systems contributions and total energy expenditure during a CrossFit® benchmark workout performed in the extreme intensity domain. Fourteen highly trained male CrossFitters, aged 28.3 ± 5.4 years, with height 177.8 ± 9.4 cm, body mass 87.9 ± 10.5 kg and 5.6 ± 1.8 years of training experience, performed the Isabel workout at maximal exertion. Cardiorespiratory variables were measured at baseline, during exercise and the recovery period, with blood lactate and glucose concentrations, including the ratings of perceived exertion, measured pre- and post-workout. The Isabel workout was 117 ± 10 s in duration and the VO2 peak was 47.2 ± 4.7 mL·kg-1·min-1, the primary component amplitude was 42.0 ± 6.0 mL·kg-1·min-1, the time delay was 4.3 ± 2.2 s and the time constant was 14.2 ± 6.0 s. The accumulated VO2 (0.6 ± 0.1 vs. 4.8 ± 1.0 L·min-1) value post-workout increased substantially when compared to baseline. Oxidative phosphorylation (40%), glycolytic (45%) and phosphagen (15%) pathways contributed to the 245 ± 25 kJ total energy expenditure. Despite the short ~2 min duration of the Isabel workout, the oxygen-dependent and oxygen-independent metabolism energy contributions to the total metabolic energy release were similar. The CrossFit® Isabel requires maximal effort and the pattern of physiological demands identifies this as a highly intensive and effective workout for developing fitness and conditioning for sports.
Subject(s)
Benchmarking , Energy Metabolism , Male , Humans , Kinetics , Exercise , OxygenABSTRACT
Concepts about motor unit recruitment are important learning contents in exercise physiology and biomechanics classes that are usually taught theoretically. In the last few years, great advances have occurred in the decomposition of surface electromyography, allowing the learning of theoretical contents in an experimental way. In this tutorial paper, we have described the decomposition of surface electromyography methodological aspects and examples to teach motor unit recruitment concepts in exercise physiology and biomechanics practical lessons. This work has the aim to facilitate physiology and biomechanics academics to introduce this technique in practical classes.
ABSTRACT
A primaquina é o único fármaco que promove a cura radical da doença causada por P.vivax e possivelmente também por P. ovale, porém possui diversos problemas em se utilizar aprimaquina durante a gravidez, pois é um fármaco capaz de penetrar a placenta, e por não seconhecer o estado de enzima glicose-6-fosfato desidrogenase (G6DP) do feto, ametabolização do fármaco no feto pode ser deficitária. No entanto não tem se pesquisado queproblemas essa terapia pode causar a uma gravidez e a prole, o ineditismo do trabalhocontribui para o campo de estudo por elucidar os desafios que tal terapia enfrentaria. Nesseestudo foi visto que a primaquina não é capaz de ser transmitida para a prole através daamamentação, e que não afetou os parâmetros de desenvolvimento e crescimento dos jovensexpostos intra-utero ao fármaco, mas teve efeito na sobrevida dos filhotes e nocomportamento no teste de campo aberto (open-field).
Primaquine is the only drug that promotes the radical cure of the disease caused by p. Vivax and possibly also by p. Ovale, but has several problems in using primaquine during pregnancy, since it is a drug capable of penetrating the placenta, and by not knowing the state of the enzyme glucose 6-phosphate dehydrogenase (g6dp) of the fetus, the fetus in drug metabolism may be deficient. However, it has not been investigated what problems this therapy can cause to a pregnancy and the offspring, the novelty of the work contributes to the field of study to elucidate the challenges that such therapy would face. In this study, primaquine was not able to be transmitted to the offspring through breastfeeding, and did not affect the developmental and growth parameters of the intra-uterus exposed to the drug, but had an effect on the survival of the pups and behavior in the open-field test.
