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Claire Marie Jie Lin Goh, Nan Xin Wang, Andre Matthias Müller, Rowena Yap, Sarah Edney, and Falk Müller-Riemenschneider

Background: Smartphones and wrist-worn activity trackers are increasingly popular for step counting purposes and physical activity promotion. Although trackers from popular brands have frequently been validated, the accuracy of low-cost devices under free-living conditions has not been adequately determined. Objective: To investigate the criterion validity of smartphones and low-cost wrist-worn activity trackers under free-living conditions. Methods: Participants wore a waist-worn Yamax pedometer and seven different low-cost wrist-worn activity trackers continuously over 3 days, and an activity log was completed at the end of each day. At the end of the study, the number of step counts reflected on the participants’ smartphone for each of the 3 days was also recorded. To establish criterion validity, step counts from smartphones and activity trackers were compared with the pedometers using Pearson’s correlation coefficient, mean absolute percentage error, and intraclass correlation coefficient. Results: Five of the seven activity trackers underestimated step counts and the remaining two and the smartphones overestimated step counts. Criterion validity was consistently higher for the activity trackers (r = .78–.92; mean absolute percentage error 14.5%–36.1%; intraclass correlation coefficient: .51–.91) than the smartphone (r = .37; mean absolute percentage error 55.7%; intraclass correlation coefficient: .36). Stratified analysis showed better validity of smartphones among female than for male participants. Phone wearing location also affected accuracy. Conclusions: Low-cost trackers demonstrated high accuracy in recording step counts and can be considered with confidence for research purposes or large-scale health promotion programs. The accuracy of using a smartphone for measuring step counts was substantially lower. Factors such as phone wear location and gender should also be considered when using smartphones to track step counts.

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Daniel das Virgens Chagas, Kylie Hesketh, Katherine Downing, Mohammadreza Mohebbi, and Lisa M. Barnett

Background: Understanding how or whether sedentary behavior affects motor competence in young children is important considering that children spend a lot of time sedentary. The aim of this study was to examine whether sedentary behavior predicts motor competence in young children. Methods: A longitudinal study with a total of 372 children aged 3.5 years at baseline and 5 years at follow-up was conducted. Objectively measured activity patterns (i.e., using accelerometers) were conducted in a subsample with 188 children. Sedentary behavior was assessed both objectively and subjectively (parent-reported screen time). Locomotor and object control skill scores were determined using the Test of Gross Motor Development—Second Edition. A multivariable analysis was executed adjusting for potential confounders (such as age, sex, time spent in moderate- to vigorous-intensity physical activity, monitor wear time, body mass index z scores, and maternal education). Results: Sedentary behavior at either time point was not significantly associated with either locomotor or object control skills after adjusting for potential confounders. Discussion: Our results did not support the assumption that sedentary behavior affects motor competence in young children. Regardless, given the lack of consistency in the evidence base, we recommend to parents, educators, and health professionals that sedentary activities should be kept within government recommendations due to potential negative effects on child development.

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Fábio Y. Nakamura, Júlio A. Costa, Bruno Travassos, Daniel Ortuño, and José Pino-Ortega

Purpose: To investigate the internal training loads of a professional Spanish female futsal team throughout 26 weeks of training including preseason and in-season weeks and verify the impact of training period and/or training load magnitudes on heart-rate variability responses. Furthermore, we aimed to assess, intraindividually, the relationship between training load and the coefficient of variation (CV) of weekly natural log of the root mean square difference of successive normal interbeat (RR) intervals (lnRMSSDCV), obtained from ∼5 measures per week, and recorded in the seated position. Methods: A within-subject design involved 12 high-level outfield female futsal players (mean [SD] age: 23.9 [3.4] y). Results: lnRMSSD was significantly lower and lnRMSSDCV was significantly higher during the preseason (weeks 1–6) compared to in-season (weeks 7–26) (P < .001). Individually, players presented moderate to large negative correlations between lnRMSSDCV and lnRMSSD during the 26 weeks of observation. Correlations ranged between r player4 = −.41 (95% CI, −.69 to −.02) and r player12 = −.55 (−.78 to −.18). Players also presented moderate to very large positive correlations between lnRMSSDCV and session rating of perceived exertion. Correlations ranged between r player7 = .41 (.04 to .71) and r player1 = .71 (.45 to .86). Conclusion: Professional female futsal players in this study presented increased lnRMSSD and reduced lnRMSSDCV during 20 weeks into the competitive season compared to 6 weeks of preseason. Furthermore, lnRMSSDCV was negatively associated with lnRMSSD on an intraindividual basis. Finally, higher internal training loads were positively correlated with lnRMSSDCV, indicating that heart-rate variability is responsive to weekly training loads.

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Janet Hauck and Isabella Felzer-Kim

Background: This study investigated the effect of an adapted physical activity (APA) course on knowledge and perceptions of preservice trainees regarding physical activity (PA) and autism spectrum disorder in 3 areas: knowledge/perspectives, importance and ease of improving developmental domains, and importance and ease of improving motor skills. Methods: Four hundred upper-level undergraduate students were recruited to participate in this survey-based study (251 APA students and 149 non-APA students participated). Survey data were analyzed using multivariate analyses of variance. Results: Participants estimated that the moderate to vigorous PA recommendations are 39.34 minutes per day, that 46.65% of moderate to vigorous PA occurs during school, and that 61.03% of children have motor difficulties. Participants perceived activities of daily living, sleep habits, and heart health as the easiest domains to improve, and problem behaviors, social skills, and self-esteem as the most difficult domains to improve. Knowledge/perspectives regarding autism spectrum disorder and PA were different by APA exposure (F 12,324 = 3.11, P < .001). Differences included self-efficacy in providing PA advice, knowledge of PA guidelines, and willingness to provide motor assessment referrals. Students differed by APA exposure in the importance of developmental domains (F 8,381 = 4.37, P < .001) but not ease of improving those domains. Conclusion: Results suggest that APA education and contact with children with disabilities improves self-efficacy, perspectives, and knowledge of PA and motor concerns in children with autism spectrum disorder.

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Ebrahim Banitalebi, Elahe Banitalebi, Majid Mardaniyan Ghahfarokhi, Mostafa Rahimi, Ismail Laher, and Kade Davison

We designed to evaluate the effects of resistance elastic band exercises (REBEs) on cardiometabolic/obesity-related biomarkers in older females with osteosarcopenic obesity. Sixty-three patients (aged 65–80 years) with osteosarcopenic obesity and a body mass index exceeding 30 kg/m2 were enrolled in the study. The participants were randomly assigned to either an experimental group (REBE, n = 32) or a usual care group (n = 31). The experimental group completed a 12-week REBE program, three times a week and 60 min per session. There were decreases in lipid accumulation product (p = .033), visceral adipose index (p = .001), triglyceride-glucose-body mass index (p = .034), and atherogenic index of plasma (p = .028) in the experimental group compared with the usual care group. Our findings highlight the importance of an REBE program in improving combined cardiometabolic/obesity-related indices in older women with osteosarcopenic obesity. The incorporation of an REBE program may benefit individuals who are unable to tolerate or participate in more strenuous exercise programs.

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Tiereny McGuire, Kirstie Devin, Victoria Patricks, Benjamin Griffiths, Craig Speirs, and Malcolm Granat

Introduction: The COVID-19 lockdown introduced restrictions to free-living activities. Changes to these activities can be accurately quantified using combined measurement. Using activPAL3 and self-reports to collect activity data, the study aimed to quantify changes that occurred in physical activity and sedentary behavior between prelockdown and lockdown. The study also sought to determine changes in indoor and outdoor stepping. Methods: Using activPAL3, four participants recorded physical activity data prelockdown and during lockdown restrictions (February–June 2020). Single events (sitting, standing, stepping, lying) were recorded and analyzed by the CREA algorithm using an event-based approach. The analysis focused on step count, sedentary time, and lying (in bed) time; median and interquartile range were calculated. Daily steps classified as taking place indoors and outdoors were calculated separately. Results: 33 prelockdown and 92 in-lockdown days of valid data were captured. Median daily step count across all participants reduced by 14.8% (from 5,828 prelockdown to 4,963 in-lockdown), while sedentary and lying time increased by 4% and 8%, respectively (sedentary: 9.98–10.30 hr; lying: 9.33–10.05 hr). Individual variations were observed in hours spent sedentary (001: 8.44–8.66, 002: 7.41–8.66, 003: 11.97–10.59, 004: 6.29–7.94, and lying (001: 9.69–9.49, 002: 11.46–11.66, 003: 7.63–9.34, 004: 9.7–11.12) pre- and in-lockdown. Discrepancies in self-report versus algorithm classification of indoor/outdoor stepping were observed for three participants. Conclusion: The study quantitively showed lockdown restrictions negatively impacted physical activity and sedentary behavior; two variables closely linked to health outcomes. This has important implications for public health policies to help develop targeted interventions and mandates that encourage additional physical activity and lower sedentary behavior.

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David X. Marquez, Michelle A. Jaldin, Miguel Negrete, Melicia C. Whitt-Glover, and Crystal M. Glover

Physical activity (PA) has been associated with a multitude of beneficial mental and physical outcomes. It is well documented, however, that there are health disparities and inequities for segments of the population, especially as related to PA. Engagement of traditionally minoritized populations into research is essential for justice in health. We discuss a community engagement model that can be used for recruiting and retaining traditionally minoritized populations into PA research, and then we go into three major ethnic/racial groups in the United States: Latinos, African Americans, and Asian Americans. Background information of each group, cultural values that play a role in health for each of the groups, and research demonstrating how culture plays a role in the formation and implementation of PA interventions in these groups is presented.

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Marcia L. Jerram, Dane Baker, Tiaki B. Smith, Phil Healey, Lee Taylor, and Katherine Black

Purpose: Menthol mouth swills can improve endurance performance in the heat, which is attributed to attenuations in nonthermally derived thermal sensation (TS) and perception of effort. However, research in elite team-sport athletes is absent. Therefore, this study investigated the performance and TS responses to a 0.1% menthol mouth rinse (MR) or placebo (PLA) among elite male rugby union players. Method: Twenty-seven (15 Forwards and 12 Backs) elite male Super Rugby players completed two 3-minute 15-a-side rugby-specific conditioning blocks, with MR or PLA provided at the start of training (baseline), at the start of each 3-minute block (swill 1 [S1] and swill 2 [S2]), and at the end of training (swill 3 [S3]). TS was assessed using the American Society of Heating, Refrigerating and Air-Conditioning Engineers 9-point Analog Sensation Scale after each swill and at baseline (preconditioning block). Acceptability was measured after baseline swill and S3 using a 5-question Likert scale. Physical performance was measured throughout training using global positioning system metrics. Results: MR attenuated TS from baseline to S1 (P = .003, SD = 1.01) and S2 (P = .002, SD = 1.09) in Forwards only, compared with PLA. Acceptability was higher only for Forwards in MR versus PLA at baseline (P = .003, SD = 1.3) and S3 (P = .004, SD = 0.75). MR had no effect on physical performance metrics (P > .05). Conclusion: MR attenuated the rise in TS with higher acceptability at S1 and S3 (in Forwards only) with no effect on selected physical performance metrics. Longer-duration exercise (eg, a match) in hot–humid conditions eliciting markedly increased body temperatures could theoretically allow favorable changes in TS to enhance performance—these postulations warrant experimental investigation.

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David J. Scott, Massimiliano Ditroilo, Samuel T. Orange, and Phil Marshall

Purpose: To compare the effects of variable-resistance complex training (VRCT) versus traditional complex training (TCT) on strength, power, speed, and leg stiffness (Kleg) in rugby league players during a 6-week mesocycle. Methods: Twenty-four rugby league players competing in the British University and Colleges Sport Premier North Division were randomized to VRCT (n = 8), TCT (n = 8), or control (CON; n = 8). Experimental groups completed a 6-week lower-body complex training intervention (2×/wk) that involved alternating high-load resistance exercise with plyometric exercise within the same session. The VRCT group performed resistance exercises at 70% of 1-repetition maximum (1RM) + 0% to 23% of 1RM from band resistance with a 90-second intracontrast rest interval, whereas the TCT group performed resistance exercise at 93% of 1RM with a 4-minute intracontrast rest interval. Back-squat 1RM, countermovement jump peak power, reactive strength index, sprint times, and Kleg were assessed pretraining and posttraining. Results: VRCT and TCT significantly improved 1RM back squat, countermovement jump peak power, and 5-m sprint time (all P < .05). VRCT also improved Kleg, whereas TCT improved 10- and 20-m sprint times (all P < .05). Between groups, both VRCT and TCT improved 1RM back squat compared with CON (both P < .001). Additionally, VRCT improved Kleg compared with CON (right leg: P = .016) and TCT improved 20-m sprint time compared with CON (P = .042). Conclusions: VRCT and TCT can be implemented during the competitive season to improve strength, power, and 5-m sprint time. VRCT may lead to greater improvements in reactive strength index and Kleg, whereas TCT may enhance 10- and 20-m sprint times.