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Katie Potter, Robert T. Marcotte, Greg J. Petrucci, Caitlin Rajala, Deborah E. Linder, and Laura B. Balzer

Given high rates of obesity and chronic disease in both people and dogs, it is important to understand how dogs and dog owners influence each other’s health, including physical activity (PA) levels. Research suggests that dog owners who walk their dogs are more likely to meet PA guidelines than those who do not, but few studies have investigated dog walking intensity or its contribution to dog owners’ total moderate-to-vigorous PA using accelerometry. Furthermore, no studies have examined the contribution of dog walking to dogs’ total PA or the relationship between dog and dog owner PA using accelerometers on dogs. The authors used accelerometers on 33 dog owner–dog pairs to investigate (a) the intensity of dog walking behavior, (b) the contribution of dog walking to dog owners’ overall moderate-to-vigorous PA and dogs’ overall PA, and (c) the correlation between dog and dog owner PA. Dog owners wore an ActiGraph accelerometer and logged all dog walking for 7 days; dogs wore a Fitbark activity monitor. On average, 64.1% (95% confidence interval [55.2, 73.1]) of daily dog walking was moderate to vigorous intensity, and dog walking accounted for 51.2% (95% confidence interval [44.1, 58.3]) of dog owners’ daily moderate-to-vigorous PA. Dog walking accounted for 41.2% (95% confidence interval [36.0, 46.4]) of dogs’ daily PA. Dog owners’ daily steps were moderately correlated (r = .54) with dogs’ daily activity points. These findings demonstrate the interdependence of dog and dog owner PA and can inform interventions that leverage the dog–owner bond to promote PA and health in both species.

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Brendan L. Pinto, Daniel Viggiani, and Jack P. Callaghan

The lumbar extensor spinae (LES) has an oblique orientation with respect to the compressive axis of the lumbar spine, allowing it to counteract anterior shear forces. This mechanical advantage is lost as spine flexion angle increases. The LES orientation can also alter over time as obliquity decreases with age and is associated with decreased strength and low back pain. However, it is unknown if LES orientation is impacted by recent exposures causing adaptations over shorter timescales. Hence, the effects of a 10-minute sustained spine flexion exposure on LES orientation, thickness, and activity were investigated. Three different submaximally flexed spine postures were observed before and after the exposure. At baseline, orientation (P < .001) and thickness (P = .004) decreased with increasingly flexed postures. After the exposure, obliquity further decreased at low (pairwise comparison P < .001) and moderately (pairwise comparison P = .008) flexed postures. Low back creep occurred, but LES thickness did not change, indicating that decreases in orientation were not solely due to changes in muscle length at a given posture. Activation did not change to counteract decreases in obliquity. These changes encompass a reduced ability to offset anterior shear forces, thus increasing the potential risk of anterior shear-related injury or pain after low back creep-generating exposures.

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Jack P. Callaghan

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Ali Brian, Angela Starrett, Adam Pennell, Pamela Haibach-Beach, Emily Gilbert, Alexandra Stribing, Sally Taunton Miedema, and Lauren Lieberman

Youth with visual impairments are more likely to be overweight than peers without visual impairments and often struggle with their locomotor skills. Locomotor development can combat unhealthy body weight statuses by supporting physical activity behaviors. There are no longitudinal investigations concerning the locomotor skill and body mass index (BMI) developmental trajectories of youth with visual impairments. The purpose of this study was to examine the 3-year developmental trajectory of the locomotor skills and BMI of youth with visual impairments including differential effects of self-reported gender and degree of vision. Participants (N = 34, M age = 11.75 years, 47% female) showed severely delayed and arrested locomotor development with increases in BMI across 3 years regardless of self-reported gender or degree of vision. Participants failed to breech a proficiency barrier of motor competence to combat against increases in BMI across time. Additional longitudinal inquiries are needed.

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Ryota Ashizawa, Kazuma Yamashita, Koki Take, Kengo Okawara, Eri Mochizuki, Asuka Sakamoto, and Yoshinobu Yoshimoto

The purpose of this single-masked randomized clinical trial was to examine whether nonleisure-time physical activity guidance (NLTPAG) improves physical activity levels in patients after minor ischemic stroke. Patients who had been hospitalized for minor ischemic stroke in an acute care hospital (National Health Institute Stroke Scale ≤ 5) were randomized to either an NLTPAG group (n = 17) or a leisure-time physical activity guidance group (n = 16). NLTPAG focused on reducing sedentary behavior and increasing the frequency of walking for shopping and household activities to improve physical activity levels in daily life. Physical activity levels significantly improved only in participants in the NLTPAG group (initial assessment: metabolic equivalents of task = 12.6; final assessment: metabolic equivalents of task = 14.8; p = .035, r = .51). These results suggest that NLTPAG may be effective for improving physical activity levels in patients after minor ischemic stroke.

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Joseph O.C. Coyne, Aaron J. Coutts, Robert U. Newton, and G. Gregory Haff

Purpose: To investigate the relationships between internal and external training load (TL) metrics with elite international women’s basketball performance. Methods: Sessional ratings of perceived exertion, PlayerLoad/minute, and training duration were collected from 13 elite international-level female basketball athletes (age 29.0 [3.7] y, stature 186.0 [9.8] cm, body mass 77.9 [11.6] kg) during the 18 weeks prior to the International Basketball Federation Olympic qualifying event for the 2016 Rio Olympic Games. Training stress balance, differential load, and the training efficiency index were calculated with 3 different smoothing methods. These TL metrics and their change in the last 21 days prior to competition were examined for their relationship to competition performance as coach ratings of performance. Results: For a number of TL variables, there were consistent significant small to moderate correlations with performance and significant small to large differences between successful and unsuccessful performances. However, these differences were only evident for external TL when using exponentially weighted moving averages to calculate TL. The variable that seemed most sensitive to performance was the change in training efficiency index in the last 21 days prior to competition (performance r = .47–.56, P < .001 and difference between successful and unsuccessful performance P < .001, f2 = 0.305–0.431). Conclusions: Internal and external TL variables were correlated with performance and distinguished between successful and unsuccessful performances among the same players during international women’s basketball games. Manipulating TL in the last 3 weeks prior to competition may be worthwhile for basketball players’ performance, especially in internal TL.

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Anis Aloulou, Francois Duforez, Damien Léger, Quentin De Larochelambert, and Mathieu Nedelec

Purpose: To evaluate the effects of sporting activities, training loads, and athletes’ characteristics on sleep among high-level adolescent athletes, in a controlled training and academic environment. Methods: A total of 128 high-level adolescent athletes (age = 15.2 [2.0] y), across 9 different sports, completed common sleep questionnaires and were monitored daily (7.3 [2.7] d) during a typical in-season training period. Sleep was analyzed using actigraphy and sleep diaries, whereas training load was evaluated using the session rating of perceived exertion, and muscle soreness and general fatigue were reported with the aid of visual analog scales. Separate linear mixed-effects models were fitted, including the athlete as a random effect and the following variables as fixed effects: the sport practiced (categorical predictor), daily training load, age, and sex. Different models were used to compare sleep variables among sports and to assess the influence of training load, age, and sex. Results: The mean total sleep time was 7.1 (0.7) hours. Swimmers presented increased sleep fragmentation, training loads, perceived muscle soreness, and general fatigue compared with athletes who engaged in other sports. Independent of any sport-specific effects, a higher daily training load induced an earlier bedtime and reduced total sleep time and perceived sleep quality, with higher sleep fragmentation. Moreover, female athletes experienced increased total sleep time and worse sleep quality in response to stress compared with those in males. Conclusion: In a controlled training and academic environment, high-level adolescent athletes did not achieve the recommended sleep duration. Impaired sleep quality and quantity could be partially explained by increased training loads.

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Xiang Yao, Christopher Curtis, Anthony Turner, Chris Bishop, Alex Austerberry, and Shyam Chavda

Rugby union (RU) is a field-based team sport with a large number of high-intensity actions such as sprinting, change of direction, tackling, scrummaging, rucking, and mauling. Competitive success in female RU has previously been related to anthropometric and physical characteristics, and with the recent introduction of professionalism in female rugby, characterizing such physical attributes may provide insight into selection and training processes. Purpose: To identify anthropometric and physical characteristics of competitive female RU players and differences between playing positions. Methods: Twenty-two players were recruited from the top tier of female RU in the United Kingdom during the 2018–2019 Premiership season. Players were split into forwards and backs and underwent body composition testing via dual-X-ray absorptiometry and physical characteristic tests (10- and 20-m speed, 1-repetition-maximum bench press and squat, countermovement jump, drop jump, isometric midthigh pull, and 1200-m shuttle). Results: Moderate to large significant differences between playing positions in both anthropometric and physical characteristics were found (P < .01). Forwards displayed greater body mass (P = .03), fat mass (P = .01), and absolute upper-body strength (P = .03), whereas backs demonstrated superior countermovement jump height (P = .01), drop jump height (P = .01), greater reactive strength (P = .03), and speed (P = .03). Conclusion: These findings provide practitioners with a greater understanding of anthropometric and physical characteristics of professional female RU players.

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T.N. Kirk, Justin A. Haegele, and Xihe Zhu

The purpose of this inquiry was to examine the relationship between barriers to physical activity, expectancy-value variables, and physical activity engagement among adults with visual impairments. Using a descriptive correlational approach, a sample of 214 adults with visual impairments (M age = 43.14, SD = 13.67) completed questionnaires pertaining to barriers to physical activity, expectancy-value beliefs about physical activity, and physical activity engagement. Data were analyzed via correlation and hierarchical regression. The final regression model explained 20.30% of variance in physical activity (p < .001). Intrinsic value (β = 0.26, p = .01) and expectancy beliefs (β = 0.33, p < .001) each emerged as significant predictors of physical activity engagement, which suggests that expectancy-value theory may have some utility for investigating the physical activity engagement of individuals with visual impairments. However, the lack of significant contribution of other variables such as attainment and utility values, as well as barriers factors, underscores the need for additional research in this area.

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Manuel Matzka, Christoph Zinner, Philipp Kunz, Hans-Christer Holmberg, and Billy Sperlich

Purpose: (1) To compare various physiological indicators of performance during a 5 × 1500-m incremental kayak test performed on an ergometer and on-water and (2) to analyze the relationships between these indicators and the actual competition performance of elite sprint kayakers, aiming to provide information to coaches for evaluating and planning training on-water. Methods: A total of 14 male and female German elite sprint kayakers performed an incremental test both on an ergometer and on-water. The tissue saturation index of the musculus (m.) biceps brachii, oxygen consumption, ratings of perceived exertion, and levels of blood lactate were measured and compared with actual racing times. In addition, power output was monitored during ergometer testing only. Results: Oxygen consumption during the fourth (P = .02; d = 0.32) and final (fifth; P < .001; d = 0.32) steps of incremental testing was higher on-water than on the ergometer. The tissue saturation index of the m. biceps brachii was approximately 21% higher at the end of the ergometer test (P = .002; d = 1.14). During the second (P = .01; d = 0.78), third (P = .005; d = 0.93), and fourth stages (P = .005; d = 1.02), the ratings of perceived exertion for ergometer kayaking was higher. During the final step, power output was most closely correlated to 200- (r = .88), 500- (r = .93), and 1000-m (r = .86) racing times (all Ps < .01). Conclusions: During high-intensity kayaking on an ergometer or on-water, the oxygen consumption and tissue saturation index of the m. biceps brachii differ. Furthermore, at moderate to submaximal intensities, the ratings of perceived exertion were higher for ergometer than for on-water kayaking. Finally, of all parameters assessed, the power output during ergometer kayaking exhibited the strongest correlation with actual racing performance.