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João R. Pereira, Dylan P. Cliff, Eduarda Sousa-Sá, Zhiguang Zhang, Jade McNeill, Sanne L.C. Veldman, and Rute Santos

Background: This study aimed to understand whether a higher number of sedentary bouts (SED bouts) and higher levels of sedentary time (SED time) occur according to different day types (childcare days, nonchildcare weekdays, and weekends) in Australian toddlers (1–2.99 y) and preschoolers (3–5.99 y). Methods: The SED time and bouts were assessed using ActiGraph GT3X+ accelerometers. The sample was composed of 264 toddlers and 343 preschoolers. The SED bouts and time differences were calculated using linear mixed models. Results: The toddlers’ percentage of SED time was higher on nonchildcare days compared with childcare days (mean difference [MD] = 2.3; 95% confidence interval, 0.7 to 3.9). The toddlers had a higher number of 1- to 4-minute SED bouts on nonchildcare days compared with childcare days. The preschoolers presented higher percentages of SED time during nonchildcare days (MD = 3.1; 95% confidence interval, 1.6 to 4.5) and weekends (MD = 1.9; 95% confidence interval, 0.4 to 3.4) compared with childcare days. The preschoolers presented a higher number of SED bouts (1–4, 5–9, 10–19, and 20–30 min) during nonchildcare days and weekends compared with childcare days. No SED times or bout differences were found between nonchildcare days and weekends, neither SED bouts >30 minutes on toddlers nor on preschoolers. Conclusion: The SED time and bouts seem to be lower during childcare periods, which means that interventions to reduce sedentary time should consider targeting nonchildcare days and weekends.

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Aashirwad Mahajan, Satish Mahajan, and Swanand Tilekar

The primary objective of this pilot randomized controlled trial was to study the feasibility (recruitment and retention rates) for interval training and sleep hygiene (SH) in adults aged above 60 years. Thirteen out of 46 screened individuals from a home for older adults in Shirdi (Maharashtra, India) were randomly assigned by permuted block randomization to either an interval training with SH group (n = 6) or an SH alone group (n = 7). The authors measured sleep with the S+ sleep monitor manufactured by ResMed (USA) Pittsburgh Sleep Quality Index and quality of life with Short Form-12 health survey version 2. Interval training consisted of 8 weeks of stationary cycling, whereas SH consisted of lecture and handouts. Recruitment was 38.2%, retention was >80% for both the interventions, and there was one loss to follow-up in SH. Interval training and SH were feasible for older adults and supported a full-scale randomized controlled trial.

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John J. Fraser, Rachel Koldenhoven, and Jay Hertel

Context: Tibial nerve impairment and reduced plantarflexion, hallux flexion, and lesser toe flexion strength have been observed in individuals with recent lateral ankle sprain (LAS) and chronic ankle instability (CAI). Diminished plantar intrinsic foot muscles (IFMs) size and contraction are a likely consequence. Objectives: To assess the effects of ankle injury on IFM size at rest and during contraction in young adults with and without LAS and CAI. Setting: Laboratory. Design: Cross-sectional. Patients: A total of 22 healthy (13 females; age = 19.6 [0.9], body mass index [BMI] = 22.5 [3.2]), 17 LAS (9 females; age =21.8 [4.1], BMI = 24.1 [3.7]), 21 Copers (13 females; age = 20.8 [2.9], BMI = 23.7 [2.9]), and 20 CAI (15 females; age = 20.9 [4.7], BMI = 25.1 [4.5]). Main Outcome Measures: Foot Posture Index (FPI), Foot Mobility Magnitude (FMM), and ultrasonographic cross-sectional area of the abductor hallucis, flexor digitorum brevis, quadratus plantae, and flexor hallucis brevis were assessed at rest, and during nonresisted and resisted contraction. Results: Multiple linear regression analyses assessing group, sex, BMI, FPI, and FMM on resting and contracted IFM size found sex (B = 0.45; P < .001), BMI (B = 0.05; P = .01), FPI (B = 0.07; P = .05), and FMM × FPI interaction (B = −0.04; P = .008) accounted for 19% of the variance (P = .002) in resting abductor hallucis measures. Sex (B = 0.42, P < .001) and BMI (B = 0.03, P = .02) explained 24% of resting flexor digitorum brevis measures (P < .001). Having a recent LAS (B = 0.06, P = .03) and FMM (B = 0.04, P = .02) predicted 11% of nonresisted quadratus plantae contraction measures (P = .04), with sex (P < .001) explaining 13% of resting quadratus plantae measures (B = 0.24, P = .02). Both sex (B = 0.35, P = .01) and FMM (B = 0.15, P = .03) predicted 16% of resting flexor hallucis brevis measures (P = .01). There were no other statistically significant findings. Conclusions: IFM resting ultrasound measures were primarily determined by sex, BMI, and foot phenotype and not injury status. Routine ultrasound imaging of the IFM following LAS and CAI cannot be recommended at this time but may be considered if neuromotor impairment is suspected.

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Sergio Jiménez-Rubio, José Luis Estévez Rodríguez, and Archit Navandar

Context: The high rates of adductor injuries and reinjuries in soccer have suggested that the current rehabilitation programs may be insufficient; therefore, there is a need to create prevention and reconditioning programs to prepare athletes for the specific demands of the sport. Objective: The aim of this study is to validate a rehab and reconditioning program (RRP) for adductor injuries through a panel of experts and determine the effectiveness of this program through its application in professional soccer. Design: A 20-item RRP was developed, which was validated by a panel of experts anonymously and then applied to 12 injured male professional soccer players. Setting: Soccer pitch and indoor gym. Participants: Eight rehabilitation fitness coaches (age = 33.25 [2.49] y) and 8 academic researchers (age = 38.50 [3.74] y) with PhDs in sports science and/or physiotherapy. The RRP was applied to 12 male professional players (age = 23.75 [4.97] y; height = 180.56 [8.41] cm; mass = 76.89 [3.43] kg) of the Spanish First and Second Division (La Liga). Interventions: The experts validated an indoor and on-field reconditioning program, which was based on strengthening the injured muscle and retraining conditional capacities with the aim of reducing the risk of reinjury. Main Outcome Measures: Aiken V for each item of the program and number of days taken by the players to return to full team training. Results: The experts evaluated all items of the program very highly as seen from Aiken V values between 0.77 and 0.94 (range: 0.61–0.98) for all drills, and the return to training was in 13.08 (±1.42) days. Conclusion: This RRP following an injury to the adductor longus was validated by injury experts, and initial results suggested that it could permit a faster return to team training.

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Lyndel Hewitt, Anthony D. Okely, Rebecca M. Stanley, Marjika Batterham, and Dylan P. Cliff

Background: Tummy time is recommended by the World Health Organization as part of its global movement guidelines for infant physical activity. To enable objective measurement of tummy time, accelerometer wear and nonwear time requires validation. The purpose of this study was to validate GENEActiv wear and nonwear time for use in infants. Methods: The analysis was conducted on accelerometer data from 32 healthy infants (4–25 wk) wearing a GENEActiv (right hip) while completing a positioning protocol (3 min each position). Direct observation (video) was compared with the accelerometer data. The accelerometer data were analyzed by receiver operating characteristic curves to identify optimal cut points for second-by-second wear and nonwear time. Cut points (accelerometer data) were tested against direct observation to determine performance. Statistical analysis was conducted using leave-one-out validation and Bland–Altman plots. Results: Mean temperature (0.941) and z-axis (0.889) had the greatest area under the receiver operating characteristic curve. Cut points were 25.6°C (temperature) and −0.812g (z-axis) and had high sensitivity (0.84, 95% confidence interval, 0.838–0.842) and specificity (0.948, 95% confidence interval, 0.944–0.948). Conclusions: Analyzing GENEActiv data using temperature (>25.6°C) and z-axis (greater than −0.812g) cut points can be used to determine wear time among infants for the purpose of measuring tummy time.

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Benita J. Lalor, Jacqueline Tran, Shona L. Halson, Justin G. Kemp, and Stuart J. Cormack

Purpose: To determine the impact of the quality and quantity of sleep during an international flight on subsequent objective sleep characteristics, training and match-day load, self-reported well-being, and perceptions of jet lag of elite female cricketers during an International Cricket Council Women’s T20 World Cup. Methods: In-flight and tournament objective sleep characteristics of 11 elite female cricketers were assessed using activity monitors. Seated in business class, players traveled west from Melbourne, Australia, to Chennai, India. The outbound flight departed Melbourne at 3:30 AM with a stopover in Dubai for 2 hours. The arrival time in Chennai was 8:10 PM local time (1:40 AM in Melbourne). The total travel time was 19 hours 35 minutes. Perceptual ratings of jet lag, well-being, and training and competition load were collected. To determine the impact of in-flight sleep on tournament measures, a median split was used to create subsamples based on (1) in-flight sleep quantity and (2) in-flight sleep quality (2 groups: higher vs lower). Spearman correlation coefficients were calculated to assess the bivariate associations between sleep measures, self-reported well-being, perceptual measures of jet lag, and internal training and match-day load. Results: Mean duration and efficiency of in-flight sleep bouts were 4.72 hours and 87.45%, respectively. Aggregated in-flight sleep duration was 14.64 + 3.56 hours. Players with higher in-flight sleep efficiency reported higher ratings for fatigue (ie, lower perceived fatigue) during the tournament period. Tournament sleep duration was longer, and bed and wake times were earlier compared with habitual. Compared with other nights during the tournament, sleep duration was shorter following matches. Conclusions: Maximizing in-flight sleep quality and quantity appears to have implications for recovery and sleep exhibited during competition. Sleep duration was longer than habitual except for the night of a match, which suggests that T20 matches may disrupt sleep duration.

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Camilla H. Carlsen, David McGhie, Julia K. Baumgart, and Øyvind Sandbakk

Purpose: To compare peak work rate (WRpeak) and associated physiological and biomechanical performance-determining variables between flat and uphill cross-country (XC) sit-skiing. Methods: Fifteen able-bodied male XC skiers completed 2 test sessions, each comprising four 4-minute submaximal stages, followed by an incremental test to exhaustion and a verification test in a sit-ski on a roller-ski treadmill. The test sessions were counterbalanced by the incline, being either 0.5% (FLAT) or 5% (UPHILL). The authors compared WRpeak and peak oxygen uptake, as well as physiological variables, rating of perceived exertion, gross efficiency, and cycle characteristics at identical submaximal work rate, between FLAT and UPHILL. Results: In UPHILL, WRpeak was 35% higher compared to FLAT (P < .001), despite no difference in peak oxygen uptake (P = .9). The higher WRpeak in UPHILL was achieved through more work per cycle, which was enabled by the twice as long poling time, compared to FLAT (P < .001). Submaximal gross efficiency was 0.5 to 2 percentage points lower in FLAT compared to UPHILL (P < .001), with an increasing difference as work rate increased (P < .001). Neither cycle rate nor work per cycle differed between inclines when compared at identical submaximal work rate (P > .16). Conclusions: The longer poling times utilized in uphill XC sit-skiing enable more work per cycle and better gross efficiency, thereby allowing skiers to achieve a higher WRpeak compared to flat XC sit-skiing. However, the similar values of peak oxygen uptake between inclines indicate that XC sit-skiers can tax their cardiorespiratory capacity similarly in both conditions.

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Hua Gong, Nicholas M. Watanabe, Brian P. Soebbing, Matthew T. Brown, and Mark S. Nagel

The use of big data in sport and sport management research is increasing in popularity. Prior research generally includes one of the many characteristics of big data, such as volume or velocity. The present study presents big data in a multidimensional lens by considering the use of sentiment analysis. Specifically focusing on the phenomenon of tanking, the purposeful underperformance in sport competitions, the present study considers the impact that consumers’ sentiment regarding tanking has on game attendance in the National Basketball Association. Collecting social media posts for each National Basketball Association team, the authors create an algorithm to measure the volume and sentiment of consumer discussions related to tanking. These measures are included in a predictive model for National Basketball Association home game attendance between the 2013–2014 and 2017–2018 seasons. Our results find that the volume of discussions for the home team and sentiment toward tanking by the away team impact game attendance.

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William H. Gurton, Steve H. Faulkner, and Ruth M. James

Purpose: To examine whether an ecologically valid, intermittent, sprint-based warm-up strategy impacted the ergogenic capacity of individualized sodium bicarbonate (NaHCO3) ingestion on 4-km cycling time-trial (TT) performance. Methods: A total of 8 male cyclists attended 6 laboratory visits for familiarization, determination of time to peak blood bicarbonate, and 4 × 4-km cycling TTs. Experimental beverages were administered doubleblind. Treatments were conducted in a block-randomized, crossover order: intermittent warm-up + NaHCO3 (IWSB), intermittent warm-up + placebo, control warm-up + NaHCO3 (CWSB), and control warm-up + placebo (CWP). The intermittent warm-up comprised exercise corresponding to lactate threshold (5 min at 50%, 2 min at 60%, 2 min at 80%, 1 min at 100%, and 2 min at 50%) and 3 × 10-second maximal sprints. The control warm-up comprised 16.5 minutes cycling at 150 W. Participants ingested 0.3 g·kg body mass−1 NaHCO3 or 0.03 g·kg body mass−1 sodium chloride (placebo) in 5 mL·kg body mass−1 fluid (3:2, water and sugar-free orange squash). Paired t tests were conducted for TT performance. Hematological data (blood bicarbonate and blood lactate) and gastrointestinal discomfort were analyzed using repeated-measures analysis of variance. Results: Performance was faster for CWSB versus IWSB (5.0 [6.1] s; P = .052) and CWP (5.8 [6.0] s; P = .03). Pre-TT bicarbonate concentration was elevated for CWSB versus IWSB (+9.3 mmol·L−1; P < .001) and CWP (+7.1 mmol·L−1; P < .001). Post-TT blood lactate concentration was elevated for CWSB versus CWP (+2.52 mmol·L−1; P = .022). Belching was exacerbated pre-warm-up for IWSB versus intermittent warm-up +placebo (P = .046) and CWP (P = .027). Conclusion: An intermittent, sprint-based warm-up mitigated the ergogenic benefits of NaHCO3 ingestion on 4-km cycling TT performance.

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Victor E. Ezeugwu, Piush J. Mandhane, Nevin Hammam, Jeffrey R. Brook, Sukhpreet K. Tamana, Stephen Hunter, Joyce Chikuma, Diana L. Lefebvre, Meghan B. Azad, Theo J. Moraes, Padmaja Subbarao, Allan B. Becker, Stuart E. Turvey, Andrei Rosu, Malcolm R. Sears, and Valerie Carson

Background: Movement behaviors (physical activity, sedentary time, and sleep) established in early childhood track into adulthood and interact to influence health outcomes. This study examined the associations between neighborhood characteristics and weather with movement behaviors in preschoolers. Methods: A subset of Canadian Healthy Infant Longitudinal Development birth cohort (n = 385, 50.6% boys) with valid movement behaviors data were enrolled at age 3 years and followed through to age 5 years. Objective measures of neighborhood characteristics were derived by ArcGIS software, and weather variables were derived from the Government of Canada weather website. Random forest and linear mixed models were used to examine predictors of movement behaviors. Cross-sectional analyses were stratified by age and season (winter and nonwinter). Results: Neighborhood safety, temperature, green space, and roads were important neighborhood characteristics for movement behaviors in 3- and 5-year-olds. An increase in temperature was associated with greater light physical activity longitudinally from age 3 to 5 years and also in the winter at age 5 years in stratified analysis. A higher percentage of expressways was associated with less nonwinter moderate to vigorous physical activity at age 3 years. Conclusions: Future initiatives to promote healthy movement behaviors in the early years should consider age differences, neighborhood characteristics, and season.