CrossFit is recognized as one of the fastest growing high-intensity functional training modes in the world. However, scientific data regarding the practice of CrossFit is sparse. Therefore, the objective of this study is to analyze the findings of scientific literature related to CrossFit via systematic review and meta-analysis. Systematic searches of the PubMed, Web of Science, Scopus, Bireme/MedLine, and SciELO online databases were conducted for articles reporting the effects of CrossFit training. The systematic review followed the PRISMA guidelines. The Oxford Levels of Evidence was used for all included articles, and only studies that investigated the effects of CrossFit as a training program were included in the meta-analysis. For the meta-analysis, effect sizes (ESs) with 95% confidence interval (CI) were calculated and heterogeneity was assessed using a random-effects model. Thirty-one articles were included in the systematic review and four were included in the meta-analysis. However, only two studies had a high level of evidence at low risk of bias. Scientific literature related to CrossFit has reported on body composition, psycho-physiological parameters, musculoskeletal injury risk, life and health aspects, and psycho-social behavior. In the meta-analysis, significant results were not found for any variables. The current scientific literature related to CrossFit has few studies with high level of evidence at low risk of bias. However, preliminary data has suggested that CrossFit practice is associated with higher levels of sense of community, satisfaction, and motivation.

Objectives—To report the incidence, site, and nature of injuries in amateur rugby league over three consecutive seasons. Methods—Six hundred players registered with an amateur rugby league organisation were studied over three consecutive seasons. All injuries sustained during the amateur rugby league matches were recorded. Information recorded included the date and time of injury, name of injured player, anatomical site and nature of injury, and position of the player. Results—The incidence of injury was 160.6 per 1000 player-position game hours, with forwards having a significantly higher incidence of injury than backs (182.3 per 1000 v 142.0 per 1000, χ² = 14.60, df = 1, p<0.001). Over 25% of the total injuries (40.6 per 1000) sustained during the three year period were to the head and neck, while injuries to the face (21.3 per 1000, 13.3%), abdomen and thorax (21.3 per 1000, 13.3%), and knee (17.8 per 1000, 11.1%) were less common (χ² = 21.83, df = 8, p<0.01). Muscular injuries (haematomas and strains) were the most common type of injury (45.7 per 1000, 28.5%, χ² = 17.98, df = 7, p<0.05). Significantly more injuries occurred in the latter stages of the season (χ² = 22.94, df = 1, p<0.001), with most injuries (70.8%, χ² = 162.29, df = 1, p<0.001) sustained in the second half of matches. Conclusions—The results show that muscular injuries and injuries to the head and neck are the most commonly sustained injuries in amateur rugby league. Furthermore, injuries are more often sustained in the latter stages of the season and during the second half of matches. These findings suggest that fatigue or accumulative microtrauma, or both, may contribute to injuries in amateur rugby league players.

Heat-related illnesses, which range from heat exhaustion to heatstroke, affect thousands of individuals worldwide every year and are characterized by extreme hyperthermia with the core body temperature (CBT) usually > 40 °C, decline in physical and athletic performance, CNS dysfunction, and, eventually, multiorgan failure. The measurement of CBT has been shown to predict heat-related illness and its severity, but the current measurement methods are not practical for use in high acuity and high motion settings due to their invasive and obstructive nature or excessive costs. Noninvasive predictions of CBT using wearable technology and predictive algorithms offer the potential for continuous CBT monitoring and early intervention to prevent HRI in athletic, military, and intense work environments. Thus far, there has been a lack of peer-reviewed literature assessing the efficacy of wearable devices and predictive analytics to predict CBT to mitigate heat-related illness. This systematic review identified 20 studies representing a total of 25 distinct algorithms to predict the core body temperature using wearable technology. While a high accuracy in prediction was noted, with 17 out of 18 algorithms meeting the clinical validity standards. few algorithms incorporated individual and environmental data into their core body temperature prediction algorithms, despite the known impact of individual health and situational and environmental factors on CBT. Robust machine learning methods offer the ability to develop more accurate, reliable, and personalized CBT prediction algorithms using wearable devices by including additional data on user characteristics, workout intensity, and the surrounding environment. The integration and interoperability of CBT prediction algorithms with existing heat-related illness prevention and treatment tools, including heat indices such as the WBGT, athlete management systems, and electronic medical records, will further prevent HRI and increase the availability and speed of data access during critical heat events, improving the clinical decision-making process for athletic trainers and physicians, sports scientists, employers, and military officers.

The aim of this study was to validate the quantification of internal training load (session rating perceived exertion, sRPE) and the effect of recall timing of sRPE during high-intensity functional training (HIFT) sessions. Thirteen male HIFT practitioners (age 27.2 ± 33 years, height 177.1 ± 4.0 cm, body mass 81.1 ± 9.0 kg) were monitored during two common HIFT training sessions: Fight Gone Bad (FGB) and Fran. The Edwards summated heart-rate-zone method was used as a reference measure of internal training load. The session-RPE rating was obtained using the CR-10 scale modified by Foster. The training load calculated by the Edwards-TRIMP index was significantly higher (p < 0.05) during the FGB (77.7 ± 4.9) than the Fran (19.8 ± 8.4) workout. There was a strong correlation (p < 0.05) between the Edwards-TRIMP index and the training load calculated by the sRPE in all time frames (0, 10, 20, and 30 min post-exercise). The RPE and sRPE measured at 30 min post-exercise time frame was significant lower than 0, 10, and 20 min post-exercise for both workouts. The session-RPE method is an easy and valid tool to evaluate internal training load for high intensity functional training practitioners.

Objectives—To investigate the physiological and anthropometric characteristics of amateur rugby league players.Methods—Thirty five amateur rugby league players (19 forwards and 16 backs) were measured for height, body mass, percentage body fat (sum of four skinfolds), muscular power (vertical jump), speed (10 m and 40 m sprint), and maximal aerobic power (multistage fitness test). Data were also collected on match frequency, training status, playing experience, and employment related physical activity levels.Results—The 10 m and 40 m sprint, vertical jump, percentage body fat, and multistage fitness test results were 20–42% poorer than previously reported for professional rugby league players. Compared with forwards, backs had significantly (p<0.01) lower body mass (79.7 (74.7–84.7) kgv90.8 (86.2–95.4) kg) and significantly (p0.05) between forwards and backs. When compared with professional rugby league players, the training status of amateur rugby league players was 30–53% lower, with players devoting less than three hours a week to team training sessions and about 30 minutes a week to individual training sessions. The training time devoted to the development of muscular power (about 13 minutes a week), speed (about eight minutes a week), and aerobic fitness (about 34 minutes a week) did not differ significantly (p>0.05) between forwards and backs. At the time of the field testing, players had participated, on average, in one 60 minute match every eight days.Conclusions—The physiological and anthropometric characteristics of amateur rugby league players are poorly developed. These findings suggest that position specific training does not occur in amateur rugby league. The poor fitness of non-elite players may be due to a low playing intensity, infrequent matches of short duration, and/or an inappropriate training stimulus.