Context: Existing anterior cruciate ligament (ACL) injury prevention programs have failed to reverse the high rate of ACL injuries in adolescent female athletes. Objective: This investigation attempts to overcome factors that limit efficacy with existing injury prevention programs through the use of a novel, objective, and real-time interactive visual feedback system designed to reduce the biomechanical risk factors associated with ACL injuries. Design: Cross-over study. Setting: Medical center laboratory. Participants: A total of 20 females (age = 19.7 [1.34] y; height = 1.74 [0.09] m; weight = 72.16 [12.45] kg) participated in this study. Methods: Participants performed sets of 10 bodyweight squats in each of 8 training blocks (ie, 4 real-time and 4 control blocks) and 3 testing blocks for a total of 110 squats. Feedback conditions were blocked and counterbalanced with half of participants randomly assigned to receive the real-time feedback block first and half receiving the control (sham) feedback first. Results: Heat map analysis revealed that during interaction with the real-time feedback, squat performance measured in terms of key biomechanical parameters was improved compared with performance when participants squatted with the sham stimulus. Conclusions: This study demonstrates that the interactive feedback system guided participants to significantly improve movement biomechanics during performance of a body weight squat, which is a fundamental exercise for a longer term ACL injury risk reduction intervention. A longer training and testing period is necessary to investigate the efficacy of this feedback approach to effect long-term adaptations in the biomechanical risk profile of athletes.
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Scott Bonnette, Christopher A. DiCesare, Adam W. Kiefer, Michael A. Riley, Kim D. Barber Foss, Staci Thomas, Katie Kitchen, Jed A. Diekfuss and Gregory D. Myer
Jordan Andre Martenstyn, Lauren Powell, Natasha Nassar, Mark Hamer and Emmanuel Stamatakis
Background: Previous epidemiological studies examining the association between physical activity (PA) and mortality risk have measured absolute PA intensity using standard resting metabolic rate reference values that fail to consider individual differences. This study compared the risk of all-cause and cardiovascular mortality between absolute and corrected estimates of PA volume. Methods: 49,982 adults aged ≥40 years who participated in the Health Survey for England and Scottish Health Survey in 1994–2008 were included in our study. PA was classified as absolute or corrected metabolic equivalent (MET)-hours per week, taking participant’s weight, height, age, and sex into account. Cox regression models were used to examine the association between absolute and corrected PA volumes and all-cause and cardiovascular mortality. Results: The authors found no difference in the association between levels of PA and risk of all-cause and cardiovascular mortality for absolute and corrected MET-hours per week, although there was a consistent decrease in mortality risk with increasing PA. There was no difference in mortality when analyses were stratified by sex, age, and body mass index. Conclusions: The association between PA volume and risk of mortality was similar regardless of whether PA volume was estimated using absolute or corrected METs. There is no empirical justification against the use of absolute METs to estimate PA volume from questionnaires.
Pål Haugnes, Jan Kocbach, Harri Luchsinger, Gertjan Ettema and Øyvind Sandbakk
Purpose: To investigate fluctuations in speed, work rate, and heart rate (HR) when cross-country ski skating across varying terrains at different endurance-training intensities. Methods: Seven male junior Norwegian skiers performed maximal-speed (V max) tests in both flat and uphill terrains. Thereafter, 5-km sessions at low (LIT), moderate (MIT), and high intensity (HIT) were performed based on their own perception of intensity while monitored by a global navigation satellite system with integrated barometry and accompanying HR monitor. Results: Speed, HR, and rating of perceived exertion gradually increased from LIT to MIT and HIT, both for the total course and in flat and uphill terrains (all P < .05). Uphill work rates (214  W, 298  W, and 350  W for LIT, MIT, and HIT, respectively) and the corresponding percentage of maximal HR (79.2% [6.1]%, 88.3% [2.4]%, and 91.0% [1.7]%) were higher than in flat terrain (159  W, 206  W, and 233  W vs 72.3% [6.3]%, 83.2% [2.3]%, and 87.4% [2.0]% for LIT, MIT, and HIT, respectively) (all P < .01). In general, ∼13% point lower utilization of maximal work rate was reached in uphill than in flat terrain at all intensities (all P < .01). Conclusions: Cross-country ski training across varying terrains is clearly interval based in terms of speed, external work rate, and metabolic intensity for all endurance-training intensities. Although work rate and HR were highest in uphill terrain at all intensities, the utilization of maximal work rate was higher in flat terrain. This demonstrates the large potential for generating external work rate when uphill skiing and the corresponding downregulation of effort due to the metabolic limitations.
Richard J. Boergers, Thomas G. Bowman, Nicole Sgherza, Marguerite Montjoy, Melanie Lu and Christopher W. O’Brien
In 2015, new practice recommendations to remove equipment prior to transport when cervical spine injury is suspected were released. The purpose of this study was to determine current emergency management practices and perceptions of the new practice recommendation. We received completed mixed-method surveys from 143 athletic trainers practicing in the Mid-Atlantic region (response rate = 10.11%). The majority of respondents stated that the number of personnel required, along with the training and time to practice equipment removal, were barriers to implementation. Requiring assistance from emergency medical services (EMS) was common, but many failed to practice with local EMS. Emergency management procedures should be appropriate given the resources (personnel and training) available. Collaboration between athletic trainers and EMS is needed.
Lindsay E. Kipp, Nicole D. Bolter and Alison Phillips Reichter
Purpose: Girls participating in aesthetic sports may be at risk for disordered eating and low self-esteem. Informed by self-determination theory, the authors examined motivational climate profiles to understand how climate dimensions differentially relate to psychological needs satisfaction, self-esteem, and disordered eating. Methods: Female gymnasts, divers, and figure skaters (N = 183; mean age = 13.5) completed a survey to assess perceptions of the motivational climate, perceived sport competence, autonomy, relatedness, self-esteem, and dieting. Pubertal status was assessed to control for developmental differences. Results: Three profiles emerged: High Important Role/Low Performance, High Effort and Cooperation/High Rivalry, and Low Mastery/High Unequal Recognition and Punishment. A 3 × 2 multivariate analysis of variance revealed profile groups significantly differed on perceived autonomy, coach relatedness, and teammate relatedness. In addition, perceived competence, self-esteem, and dieting significantly differed by pubertal status. For autonomy, the High Important Role/Low Performance group reported the highest scores. For coach and teammate relatedness, the Low Mastery/High Unequal Recognition and Punishment group reported significantly lower scores than the other 2 groups. Postpubertal girls reported lower sport ability and self-esteem and greater dieting. Conclusion: Physical maturity and social context were important in explaining girls’ psychological needs satisfaction and well-being. Results add to the authors’ understanding of the complex nature and influence of the motivational climate.
Nura Alwan, Samantha L. Moss, Kirsty J. Elliott-Sale, Ian G. Davies and Kevin Enright
Physique competitions are events in which aesthetic appearance and posing ability are valued above physical performance. Female physique athletes are required to possess high lean body mass and extremely low fat mass in competition. As such, extended periods of reduced energy intake and intensive training regimens are used with acute weight loss practices at the end of the precompetition phase. This represents an increased risk for chronic low energy availability and associated symptoms of relative energy deficiency in sport, compromising both psychological and physiological health. Available literature suggests that a large proportion of female physique athletes report menstrual irregularities (e.g., amenorrhea and oligomenorrhea), which are unlikely to normalize immediately postcompetition. Furthermore, the tendency to reduce intakes of numerous essential micronutrients is prominent among those using restrictive eating patterns. Following competition, reduced resting metabolic rate, and hyperphagia, is also a concern for these female athletes, which can result in frequent weight cycling, distorted body image, and disordered eating/eating disorders. Overall, female physique athletes are an understudied population, and the need for more robust studies to detect low energy availability and associated health effects is warranted. This narrative review aims to define the natural female physique athlete, explore some of the physiological and psychological implications of weight management practices experienced by female physique athletes, and propose future research directions.
Katrina M. Moss, Annette J. Dobson, Kimberley L. Edwards, Kylie D. Hesketh, Yung-Ting Chang and Gita D. Mishra
Background: Play equipment at home could be targeted in interventions to increase children’s physical activity (PA), but evidence is mixed, potentially because current methods do not reflect children’s lived experience. This study investigated associations between combinations of equipment and PA. Methods: Data were from the Mothers and their Children’s Health study and the Australian Longitudinal Study on Women’s Health. Mothers (n = 2409) indicated the types of fixed active (eg, trampolines), portable active (eg, bicycles), and electronic (eg, computers) equipment at home, and the number of days children (n = 4092, aged 5–12 y, 51% boys) met PA guidelines. Latent class analysis was used to identify combinations of equipment, and linear regressions were used to investigate associations with PA. Results: Compared with children with high active (fixed and portable) and medium electronic equipment, children with portable active and medium (B = −0.53; 95% confidence interval, −0.72 to −0.34) or high (B = −0.58; 95% confidence interval, −0.83 to −0.33) electronic equipment met the guidelines on fewer days. Children with similar active equipment (but more electronic equipment) met the PA guidelines on fewer days (mean difference = −0.51, SE = 0.14, P = .002). Conclusion: Having the right combination of play equipment at home may be important for children’s PA.
Stephen Hunter, Andrei Rosu, Kylie D. Hesketh, Ryan E. Rhodes, Christina M. Rinaldi, Wendy Rodgers, John C. Spence and Valerie Carson
Purpose: Examine objectively measured environmental correlates of physical activity and sedentary behavior in toddlers (12–35 mo). Methods: Participants were recruited at immunization appointments in Edmonton, Canada. Physical activity and sedentary time were objectively measured via accelerometers (n = 149). The parents reported screen time and demographic characteristics via a questionnaire (n = 249). Postal codes were used to link neighborhood data via geographic information systems. Neighborhood data included 4 environmental domains: functional (ie, walkability), safety (ie, crime), esthetic (ie, tree density), and destination (ie, cul-de-sac density, wooded area percentage, green space percentage, recreation density, park density). Weather data (temperature and precipitation) were obtained via historical weather records. Multilevel multiple linear regression models were used to account for clustering of participants within neighborhoods and adjustment of demographic variables. Results: Each additional 10°C of mean temperature was significantly associated with 5.74 (95% confidence interval, 0.96–10.50) minutes per day of higher light-intensity physical activity, though the effect size was small (f 2 = 0.08). No other significant associations were observed. Conclusions: The lack of significant findings for neighborhood environment factors suggests proximal factors (eg, features of the home environment) may be more important in predicting toddlers’ physical activity and sedentary behavior. More indoor physical activity opportunities may be needed on colder days for toddlers.
Grégoire P. Millet and Kilian Jornet
Purpose: To present the acclimatization strategy employed by an elite athlete prior to 2 successful ascents to Mount Everest (including a “fastest known time”) in 1 wk. Methods: Training volume, training content, and altitude exposure were recorded daily. Vertical velocity was recorded by GPS (global positioning system) heart-rate monitor. Results: The subject first used a live high–train low and high preacclimatization method in normobaric hypoxia (NH). Daily, he combined sleeping in a hypoxic tent (total hours: ∼260) and exercising “as usual” in normoxia but also in NH (altitude >6000 m: 30 h), including at high intensity. The hypoxic sessions were performed at the second threshold on treadmill in NH at 6000 m, and the pulse saturation increased from 70% to 85% over 1 mo. Then, the subject was progressively exposed to hypobaric hypoxia, first in the Alps and then in the Himalayas. On day 18, he reached for the second time an altitude >8000 m with the fastest vertical velocity (350 m/h) ever measured between 6300 and 8400 m. Afterward, he climbed twice in a week to the summit of Mount Everest (8848 m, including a “fastest known time” of 26.5 h from Rongbuk Monastery, 5100 m). Conclusion: Overall, this acclimatization was successful and in line with the most recent recommendations: first, using live high–train low and high, and second, using hypobaric hypoxia at increasing altitudes for a better translation of the NH benefits to hypobaric hypoxia. This case study reports the preparation for the most outstanding performance ever acheived at an extreme altitude.