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Marcin Straczkiewicz, Nancy W. Glynn, Vadim Zipunnikov and Jaroslaw Harezlak

Background: The increasing popularity of wrist-worn accelerometers introduces novel challenges to the research on physical activity and sedentary behavior. Estimation of body posture is one such challenge. Methods: The authors proposed an approach called SedUp to differentiate between sedentary (sitting/lying) and standing postures. SedUp is based on the logistic regression classifier, using the wrist elevation and the motion variability extracted from raw accelerometry data collected on the axis parallel to the forearm. The authors developed and tested our method on data from N = 45 community-dwelling older adults. All subjects wore ActiGraph GT3X+ accelerometers on the left and right wrist, and activPAL was placed on the thigh in the free-living environment for 7 days. ActivPAL provided ground truth about body posture. The authors reported SedUp’s classification accuracy for each wrist separately. Results: Using the data from the left wrist, SedUp estimated the standing posture with median true positive rate = 0.83 and median true negative rate = 0.91. Using the data from the right wrist, SedUp estimated the standing posture with median true positive rate = 0.86 and median true negative rate = 0.93. Conclusions: SedUp provides accurate classification of body posture using wrist-worn accelerometers. The separate validation for each wrist allows for the application of SedUp in a wide spectrum of free-living studies.

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Justin B. Hollander, Ann Sussman, Peter Lowitt, Neil Angus and Minyu Situ

Background: Understanding more about the unseen side of our responses to visual stimuli offers a powerful new tool for transportation planning. Traditional transportation planning tends to focus on the mobility of vehicles rather than on opportunities to encourage sustainable transport modes, like walking. Methods: Using eye-tracking emulation software, this study measured the unconscious visual responses people have to designs and layouts in new built environments, focusing on what makes streets most walkable. Results: The study found key differences between the way the brain takes in conventional automobile-oriented residential developments versus new urbanist layouts, with the former lacking key fixation points. Conclusion: The study’s discoveries significantly explain why new urbanist layouts promote walking effortlessly and conventional automobile-oriented residential developments cannot.

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Geeta Sharma, Tom Stewart and Scott Duncan

Background: Curriculum-integrated dance programs are a promising but relatively under-researched strategy for increasing children’s physical activity (PA). The aim of this study was to determine the impact of a curriculum-integrated dance program on children’s PA. Methods: A total of 134 primary children aged 7–9 years from 4 New Zealand schools were assigned to either a dance group (n = 78) or a control group (n = 56). The dance group participated in a 6-week curriculum-integrated dance program during school time. Although the dance program focused on curricular learning, fitness and coordination were embedded in the dance sessions. Intensity of PA varied according to the focus of each dance session. PA was measured at baseline and postintervention using a waist-mounted ActiGraph GT3X+ accelerometer for 8 consecutive days. Results: There were no significant intervention effects on PA levels between the dance and control groups postintervention. Conclusion: Dance-embedded learning did not increase overall levels of PA in this study. Future studies may consider assessing longer term effects of a dance-based intervention, or programs that place more focus on PA promotion.

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Ángel Luis Clemente Remón, Víctor Jiménez Díaz-Benito, José Emilio Jiménez Beatty and José Antonio Santacruz Lozano

The study aimed to ascertain the levels of older European people’s physical activity according to sociodemographic variables. The sample size was 7,893 citizens aged 65 and over from the European Union. The participants were classified as physically inactive, adequately active, or highly active, according to the World Health Organization. The total metabolic equivalents of task minutes per week were also calculated. In the results, 55.5% of older people were adequately active, and 43.8% were highly active, especially in the North and West. The average metabolic equivalents of task minutes per week was 1,313 metabolic equivalents of task minutes, with walking as the main activity, followed by moderate physical activity and vigorous activity. Male older people of a lower age from the North and West, with a higher level of education and less difficulty in paying bills, were more likely to be physically active. As a conclusion, only slightly more than half the population were adequately active. These sociodemographic inequalities show the necessity of implementing specific measures.

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Jarle Stålesen, Thomas Westergren, Bjørge Herman Hansen and Sveinung Berntsen

Background: Smartphones with embedded sensors, such as accelerometers, are promising tools for assessing physical activity (PA), provided they can produce valid and reliable indices. The authors aimed to summarize studies on the PA measurement properties of smartphone accelerometers compared with research-grade PA monitors or other objective methods across the intensity spectrum, and to report the effects of different smartphone placements on the accuracy of measurements. Methods: A systematic search was conducted on July 1, 2019 in PubMed, Embase, SPORTDiscus, and Scopus, followed by screening. Results: Nine studies were included, showing moderate-to-good agreements between PA indices derived from smartphone accelerometers and research-grade PA monitors and/or indirect calorimetry. Three studies investigated measurement properties across smartphone placements, with small differences. Large heterogeneity across studies hampered further comparisons. Conclusions: Despite moderate-to-good agreements between PA indices derived from smartphone accelerometers and research-grade PA monitors and/or indirect calorimetry, the validity of smartphone monitoring is currently challenged by poor intermonitor reliability between smartphone brands/versions, heterogeneity in protocols used for validation, the sparsity of studies, and the need to address the effects of smartphone placement.

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Alfonso Gutiérrez-Santiago, Iván Prieto-Lage, Arturo Martín and Carlos Ayán

Background: To provide information regarding injury incidence, injury pattern, and associated injury risk factors in elite Paralympic judokas. Methods: Participants in this observational research were elite judokas taking part in the IBSA 2018 World Judo Championship. The entire championship was videotaped, and all injuries were prospectively documented using an all-complaints definition. Results: The tournament featured 267 judokas, (B1 = 58; B2 = 105; B3 = 104). The injury proportion was estimated at 18.9 injuries/100 fighters (B1 = 13.8; B2 = 22.3; B3 = 18.5). A total of 745 athletic exposures were registered. The overall injury rate was 68.5 (95% CI, 52.5–89.2); 62.5 (95% CI, 32–122.3); 79.6 (95% CI, 53.8–17.8); and 61.2 (95% CI, 40–93.5) for the total sample, B1, B2, and B3 judokas, respectively. When only injuries resulting in medical attention were analyzed, the overall injury rate was calculated to be 22.8 (95% CI, 14.3–36.5), and the injury proportion was estimated at 6.3 injuries/100 fighters. No significant differences were found for sex, weight, and visual class regarding injury proportion and injury rates. Conclusion: Paralympic judokas show a high injury rate. However, when only injuries that needed medical attention were taken into account, the proportion of athletes injured was low. The degree of visual impairment was not considered as an injury risk factor.

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Jeanette M. Ricci, Todd A. Astorino, Katharine D. Currie and Karin A. Pfeiffer

The majority of studies examining children’s responses to high-intensity interval exercise primarily utilized running; however, this modality does not require/include other important aspects of physical activity including muscular fitness. Purpose: To compare acute responses between a body weight resistance exercise circuit (CIRC) and treadmill-based (TM) high-intensity interval exercise. Method: A total of 17 boys (age = 9.7 [1.3] y) completed a graded exercise test to determine peak heart rate, peak oxygen uptake (VO2peak), and maximal aerobic speed. Sessions were randomized and counterbalanced. CIRC required 2 sets of 30-second maximal repetitions of 4 exercises. TM included eight 30-second bouts of running at 100% maximal aerobic speed. Both included 30-second active recovery between bouts. Blood lactate concentration was measured preexercise and postexercise. Rating of perceived exertion, affective valence, and enjoyment were recorded preexercise, after intervals 3 and 6, and postexercise. Results: Participants attained 88% (5%) peak heart rate and 74% (9%) VO2peak for CIRC and 89% (4%) peak heart rate and 81% (6%) VO2peak for TM, with a significant difference in percentage of VO2peak (P = .003) between protocols. Postexercise blood lactate concentration was higher following CIRC (5.0 [0.7] mM) versus TM (2.0 [0.3] mM) (P < .001). Rating of perceived exertion, affective valence, and enjoyment responses did not differ between protocols (P > .05). Conclusion: HR responses were near maximal during CIRC, supporting that this body-weight circuit is representative of high-intensity interval exercise.

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Rafael E.A. Muchaxo, Sonja de Groot, Lucas H.V. van der Woude, Thomas W.J. Janssen and Carla Nooijen

The classification system for handcycling groups athletes into five hierarchical classes, based on how much their impairment affects performance. Athletes in class H5, with the least impairments, compete in a kneeling position, while athletes in classes H1 to H4 compete in a recumbent position. This study investigated the average time-trial velocity of athletes in different classes. A total of 1,807 results from 353 athletes who competed at 20 international competitions (2014–2018) were analyzed. Multilevel regression was performed to analyze differences in average velocities between adjacent pairs of classes, while correcting for gender, age, and event distance. The average velocity of adjacent classes was significantly different (p < .01), with higher classes being faster, except for H4 and H5. However, the effect size of the differences between H3 and H4 was smaller (d = 0.12). Hence, results indicated a need for research in evaluating and developing evidence-based classification in handcycling, yielding a class structure with meaningful performance differences between adjacent classes.

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Nathan Waite, John Goetschius and Jakob D. Lauver

Runners experience repeated impact forces during training, and the culmination of these forces can contribute to overuse injuries. The purpose of this study was to compare peak vertical tibial acceleration (TA) in trained distance runners on 3 surface types (grass, asphalt, and concrete) and 3 grades (incline, decline, and level). During visit 1, subjects completed a 1-mile time trial to determine their pace for all running trials: 80% (5%) of the average time trial velocity. During visit 2, subjects were outfitted with a skin-mounted accelerometer and performed 18 separate running trials during which peak TA was assessed during the stance phase. Each subject ran 2 trials for each condition with 2 minutes of rest between trials. Peak TA was different between decline (8.04 [0.12] g) and incline running (7.31 [0.35] g; P = .020). On the level grade, peak TA was greater during grass (8.22 [1.22] g) compared with concrete (7.47 [1.65] g; P = .017). On the incline grade, grass (7.68 [1.44] g) resulted in higher peak TA than asphalt (6.99 [1.69] g; P = .030). These results suggest that under certain grade conditions grass may result in higher TA compared with either concrete or asphalt.

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Rena F. Hale, Sandor Dorgo, Roger V. Gonzalez and Jerome Hausselle

Auditory feedback is a simple, low-cost training solution that can be used in rehabilitation, motor learning, and performance development. The use has been limited to the instruction of a single kinematic or kinetic target. The goal of this study was to determine if auditory feedback could be used to simultaneously train 2 lower-extremity parameters to perform a bodyweight back squat. A total of 42 healthy, young, recreationally active males participated in a 4-week training program to improve squat biomechanics. The Trained group (n = 22) received 4 weeks of auditory feedback. Feedback focused on knee flexion angle and center of pressure under the foot at maximum squat depth. The Control group (n = 20) performed squats without feedback. Subjects were tested pre, post, and 1 week after training. The Trained group achieved average target knee flexion angle within 1.73 (1.31) deg (P < .001) after training and 5.36 (3.29) deg (P < .01) at retention. While achieving target knee flexion angle, the Trained group maintained target center of pressure (P < .001). The Control group improved knee range of motion, but were not able to achieve both parameter targets at maximum squat depth (P < .90). Results from this study demonstrate that auditory feedback is an effective way to train 2 independent biomechanical targets simultaneously.