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Paul Mackie, Gary Crowfoot, Prajwal Gyawali, Heidi Janssen, Elizabeth Holliday, David Dunstan, and Coralie English

Background: Interrupting prolonged sitting can attenuate postprandial glucose responses in overweight adults. The dose–response effect in stroke survivors is unknown. The authors investigated the effects of interrupting 8 hours of prolonged sitting with increasingly frequent bouts of light-intensity standing-based exercises on the postprandial glucose response in stroke survivors. Methods: Within-participant, laboratory-based, dose-escalation trial. Participants completed three 8-hour conditions: prolonged sitting and 2 experimental conditions. Experimental conditions involved light-intensity standing-based exercises of increasing frequency (2 × 5 min to 6 × 5 min bouts). Postprandial glucose is reported. Results: Twenty-nine stroke survivors (aged 66 y) participated. Interrupting 8 hours of prolonged sitting with light-intensity standing-based exercises every 90 minutes significantly decreased postprandial glucose (positive incremental area under the curve; −1.1 mmol/L·7 h; 95% confidence interval, −2.0 to −0.1). In the morning (08:00–11:00), postprandial glucose decreased during the 4 × 5 minutes and 6 × 5 minutes conditions (positive incremental area under the curve; −0.8 mmol/L·3 h; 95% confidence interval, −1.3 to −0.3 and −0.8 mmol/L·3 h; 95% confidence interval, −1.5 to −0.2, respectively) compared with prolonged sitting. Conclusion: Interrupting 8 hours of prolonged sitting at least every 90 minutes with light-intensity standing-based exercises attenuates postprandial glucose in stroke survivors. During the morning, postprandial glucose is attenuated when sitting is interrupted every 60 and 90 minutes.

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Kim Gammage, Alyson Crozier, Alison Ede, Christopher Hill, Sean Locke, Desi McEwan, Kathleen Mellano, Eva Pila, Matthew Stork, and Svenja Wolf

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Eduardo B. Flores, Thaís Reichert, Juliano B. Farinha, Luiz Fernando M. Kruel, and Rochelle R. Costa

Background: The present study aimed to systematically review the literature on the effects of physical training on neuromuscular parameters in patients with type 1 diabetes mellitus (T1DM). Methods: The PubMed, Scopus, EMBASE, and COCHRANE databases were accessed in September 2020. Clinical trials that evaluated the effects of physical training on neuromuscular parameters (maximum strength, resistance strength, muscle power, muscle quality, and muscle thickness) of patients with T1DM compared with a control group were considered eligible. The results were presented as the standardized mean difference with 95% confidence intervals. Effect size (ES) calculations were performed using the fixed effect method, with α = .05. Results: Combined training increased the maximum strength levels in individuals with T1DM to a lesser extent than in healthy individuals (ES: 0.363; P = .038). Strength training increased the maximum strength (ES: 1.067; P < .001), as well as combined training (ES: 0.943; P < .001); both compared with aerobic training in patients with T1DM. Strength training increased the maximum strength in a similar magnitude to combined training in patients with T1DM (ES: −0.114; P = .624). Conclusion: Both combined training and strength training represent effective strategies for improving the maximum strength in individuals with T1DM.

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Paul Ritsche, Thomas Bernhard, Ralf Roth, Eric Lichtenstein, Martin Keller, Sabrina Zingg, Martino V. Franchi, and Oliver Faude

Purpose: Hamstring muscle architecture may be associated with sprint performance and the risk of sustaining a muscle injury, both of which increase during puberty. In this study, we investigated the m. biceps femoris long head (BFlh) cross-sectional area (ACSA), fascicle length (FL) and pennation angle (PA), and sprint performance as well as their relationship in under 13 to 15 youth soccer players. Methods: We measured 85 players in under-13 (n = 29, age = 12.5 [0.1] y, height = 155.3 [6.2] cm, weight = 43.9 [7.6] kg), under-14 (n = 25, age = 13.5 [0.3] y, height = 160.6 [7.7] cm, weight = 47.0 [6.8] kg), and under-15 (n = 31, age = 14.4 [0.3] y, height = 170.0 [7.7] cm, weight = 58.1 [8.8] kg) teams. We used ultrasound to measure BFlh ACSA, FL and PA, and sprint tests to assess 10- and 30-m sprint time, maximal velocity  (v max), and maximal acceleration (α max). We calculated Pearson r to assess the relationship between sprint ability and architectural parameters. Results: All muscle architectural parameters increased from the under-13 to the under-15 age group (BFlh ACSA = 37%, BFlh FL = 11%, BFlh PA = 8%). All sprint performance parameters improved from the under-13 to under-15 age categories (30-m time = 7%, 10-m time = 4%, v max = 9%, α max = 7%). The BFlh ACSA was correlated with 30-m sprint time (r = −.61 (95% compatibility interval [CI] [−.73, −.45]) and v max (r = .61, 95% CI [.45, .72]). A combination of BFlh ACSA and age best predicted 30-m time (R² = .47 [.33, .62]) and 10-m time (R² = .23 [.08, .38]). Conclusions: Muscle architectural as well as sprint performance parameters increase from the under-13 to under-15 age groups. Even though we found correlations for all assessed architectural parameters, BFlh ACSA was best related to the assessed sprint parameters.

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Iván Peña-González, José M. Sarabia, Alba Roldan, Agustín Manresa-Rocamora, and Manuel Moya-Ramón

In regular football, the players’ selection process involves an objective assessment based on their anthropometric and physical performance. However, available literature focused on players’ selection process in cerebral palsy (CP) football is scarce. Purpose: To describe the anthropometrical and physical performance profiles of the International Spanish CP footballers and to compare them with the remaining CP football players from the national competition. Method: A total of 75 CP football players from the Spanish CP Football National Competition (classified into the 3 existing classes: football class [FT] 1 = 38; FT2 = 29; FT3 = 8) participated in the study. Participants were divided into 2 groups: selected players (n = 15) and nonselected players (n = 60) for the national team. Anthropometrical data and physical performance (countermovement jump, 20-m sprint, modified agility T-test [MAT], and dribbling test) were collected. Results: There were significant differences in the 20-m sprint, MAT, and dribbling for the total sample and in MAT and dribbling for FT2 and FT3 classes between selected players and nonselected players (P < .05), but there were no differences for FT1. The MAT and dribbling showed a positive correlation and a high percentage of player selection prediction. Conclusion: Change-of-direction ability (ie, MAT) and dribbling skills are important when performing the selection process, as they allow the evaluation of important aspects of the game, but they may also provide the technical staff with an idea of the functionality and the physical performance of the players in each sport class.

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Kelsey Saizew, M. Blair Evans, Veronica Allan, and Luc J. Martin

The authors explored how sport structure predisposed a team to subgroup formation and influenced athlete interactions and team functioning. A season-long qualitative case study was undertaken with a nationally ranked Canadian track and field team. Semistructured interviews were conducted with coaches (n = 4) and athletes (n = 11) from different event groups (e.g., sprinters, jumpers) at the beginning and at the end of the season. The results highlighted constraints that directly impacted athlete interactions and predisposed the group to subgroup formation (e.g., sport/event type, facility/schedule limitations, team size/change over time). The constraints led to structural divides that impacted interactions but could be overcome through team building, engaging with leaders, and prioritizing communication. These findings underline how structure imposed by the design of sports impacts teammate interactions and how practitioners, coaches, and athletes can manage groups when facing such constraints. The authors describe theoretical and practical implications while also proposing potential future directions.

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Benjamin Noël and Stefanie Klatt

Most studies on offside decision making in soccer have not addressed rather simplistic situational probabilities like the number of players involved in an offside situation. In three studies (one observational and two experimental), the authors tried to assess whether the number of players close to the offside situation can predict the quality of offside decision making. In all three studies, they found that the presence of additional players negatively affected the percentage of correct decisions. The exact relationship between the number of players and the decrease in decision-making performance differed between the studies, though. Importantly, there was a negative influence of the number of players on decision-making quality in Studies 2 and 3, even though the authors tried to add players clearly farther away from the offside line than the relevant pair of players. This points to a crowding effect as a potential explanation for why decision-making quality decreases with an increasing number of players.

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Christian J. Cook, Blair T. Crewther, Liam P. Kilduff, Linda L. Agnew, Phillip Fourie, and Benjamin G. Serpell

Purpose: To establish if training volume was associated with androgen baselines and androgen responsiveness to acute exercise. Methods: During a “high-volume” training phase, 28 cyclists (14 men and 14 women) undertook oxygen-uptake and maximal-work-capacity testing. Two days later, they completed a repeat-sprint protocol, which was repeated 3 weeks later during a “low-volume” phase. Blood and saliva samples were collected before and after (+5 and +60 min) the repeat-sprint protocol. Blood was assayed for total testosterone (TT), free testosterone (FT), and dihydrotestosterone (DHT) and saliva, for testosterone and DHT. Results: Pretrial TT, FT, and DHT concentration was greater for males (P < .001, large effect size differences), and in both genders TT, DHT, and saliva for DHT was higher during high-volume loading (moderate to large effect size). Area-under-the-curve analysis revealed larger TT, FT, and DHT responses to the repeat-sprint protocol among females, and high-volume training was linked to larger TT, DHT, and saliva for DHT responses (moderate to large effect size). Baseline TT and FT correlated with oxygen uptake and work capacity in both genders (P < .05). Conclusion: DHT showed no acute performance correlation but was responsive to volume of training, particularly in females. This work informs on timelines and relationships of androgenic biomarkers in males and females across different training loads, adding to the complexity that should be considered in interpretation thereof. The authors speculate that testosterone may impact acute performance via behavioral mechanisms of motivation and attention; DHT, via training volume-induced androgenic promotion, may facilitate long-term adaptive changes, especially for females.

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José María González-Ravé, Francisco Hermosilla, Fernando González-Mohíno, Arturo Casado, and David B. Pyne

A well-planned periodized approach allows swimmers to achieve peak performance at the major national and international competitions. Purpose: To identify the main characteristics of endurance training for highly trained swimmers described by the training intensity distribution (TID), volume, and periodization models. Methods: The electronic databases Scopus, PubMed, and Web of Science were searched using a comprehensive list of relevant terms. Studies that investigated the effect of the periodization of training in swimming, with the training load (volume, TID) and periodization reported, were included in the systematic review. Results: A total of 3487 studies were identified, and after removal of duplicates and elimination of papers based on title and abstract screening, 17 articles remained.  A further 8 articles were excluded after full text review, leaving a final total of 9 studies in the systematic review. The evidence levels were 1b for intervention studies (n = 3) and 2b for (observational) retrospective studies (n = 6). The sprint swimmers typically followed a polarized and threshold TID, the middle-distance swimmers followed a threshold and pyramidal TID, and the long-distance swimmers primarily followed a pyramidal TID. The periodization model identified in the majority of studies selected is characterized by wave-like cycles in units like mesocycles to promote physiological adaptations and skill acquisition. Conclusions: Highly trained swimmers follow a training volume and TID based on their primary event. There is a need for further experimental studies on the effects of block and reverse periodization models on swimming performance. Although observational studies of training have limited evidence, it is unclear whether a different training/periodization approach would yield better results.

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Eugene C. Fitzhugh, Jerry Everett, and Linda Daugherty

Background: School-aged children in the Southeast, compared with other United States of America (US) regions, have significantly lower levels of active transportation to school (ATS). The purpose of this study was to contrast the parental correlates of ATS choice specific to the Southeast with other areas of the US. Methods: This study utilized national data from 2952 households with school-aged children located within a 20-minute walk to a school. Parents reported their children’s ATS behavior and their own ATS beliefs and perceptions. Logistic regression contrasted correlates of parents from the Southeast with other regions. Results: Parents in the Southeast, compared with parents across the US, were significantly less likely to allow their child to take ATS (12.9% vs 33.3%, respectively) (odds ratio [OR] = 0.46; 95% confidence interval [CI] = 0.36–0.59). Specific to the Southeast, parental correlates linked to increases in ATS were Black race/ethnicity (OR = 1.68; 95% CI, 1.31–2.60), being single, (OR = 1.71; 95% CI, 1.15–2.54), and any parental physical activity (P value for trend = .0053). The only correlate associated with a decrease in ATS in the Southeast was heightened safety concerns (eg, traffic speed, safe crossings) (OR = 0.44; 95% CI, 0.23–0.84). Conclusions: Among households with children in the Southeast, ATS interventions that allay parental safety concerns and that promote physical activity among parents might lead to increases in ATS.