Background: This study aimed to examine whether sedentary digital media use in preadolescence increases the risk of being overweight 3 years later, and whether this association differs based on preadolescents’ leisure-time physical activity (LTPA) levels. Methods: The authors conducted a 3-year follow-up study among 4661 participants with a mean (SD) age of 11 (1) years at baseline and 14 (1) years at follow-up. A web-based questionnaire assessed sedentary digital media use and LTPA. The authors categorized baseline LTPA duration into 3 levels: 0 to 5 (low), 6 to 8 (moderate), and ≥9 (high) hours per week. In addition, the authors categorized adolescents as normal weight or overweight/obese at follow-up. Results: Greater amounts of sedentary digital media use at baseline associated with an increased risk of being overweight 3 years later even after adjusting for confounders. This only held for preadolescents with low baseline LTPA (OR = 1.14; 95% confidence interval, 1.05–1.24), but not among those with moderate (OR = 1.02; 0.91–1.15) or high (OR = 0.96; 0.85–1.08) LTPA. Conclusions: Preadolescent LTPA modified the long-term association between sedentary digital media use and being overweight; specifically, 6 hours per week or more of LTPA mitigated the increased risk of being overweight associated with higher amounts of digital media use.
Elina Engberg, Marja H. Leppänen, Catharina Sarkkola, and Heli Viljakainen
Charline Madelaine, Nicolas Benguigui, and Michèle Molina
This review addresses the question of a possible specificity of motor development of preterm children with no diagnosis of neurological impairment or major cerebral lesion. With that goal, we proceed with a narrative review on the basis of nine studies. All the studies used standardized assessments of motor abilities with a comparison methodology of preterm and full-term groups aged between 3 and 8 years. The review stresses three major findings in the preterm groups as compared with the full-term groups: (a) inferior fine motor abilities; (b) heterogeneity in motor skills; and (c) differences in efficiency of cognitive, perceptual, and mobilization of perceptual motor processes, which do not necessarily result in lower scores in global performances. These findings suggest the need of long-term medical follow-up for all preterm children whether or not they are at risk for neurodevelopmental disorder. Focusing attention on the use of sensory information for motor control in preterm children could also lead to more precise evaluations of motor abilities, which will then provide more detailed parameters for improved learning and rehabilitation programs.
Becky Breau, Berit Brandes, Marvin N. Wright, Christoph Buck, Lori Ann Vallis, and Mirko Brandes
This study explored the relationship between motor abilities and accelerometer-derived measures of physical activity (PA) within preschool-aged children. A total of 193 children (101 girls, 4.2 ± 0.7 years) completed five tests to assess motor abilities, shuttle run (SR), standing long jump, lateral jumping, one-leg stand, and sit and reach. Four PA variables derived from 7-day wrist-worn GENEActiv accelerometers were analyzed including moderate to vigorous PA (in minutes), total PA (in minutes), percentage of total PA time in moderate to vigorous PA, and whether or not children met World Health Organization guidelines for PA. Linear regressions were conducted to explore associations between each PA variable (predictor) and motor ability (outcome). Models were adjusted for age, sex, height, parental education, time spent at sports clubs, and wear time. Models with percentage of total PA time in moderate to vigorous PA were adjusted for percentage of total PA time. Regression analyses indicated that no PA variables were associated with any of the motor abilities, but demographic factors such as age (e.g., SR: ß = −0.45; 95% confidence interval [−1.64, −0.66]), parental education (e.g., SR: ß = 0.25; 95% confidence interval [0.11, 1.87]), or sports club time (e.g., SR: ß = −0.08; 95% confidence interval [−0.98, 0.26]) showed substantial associations with motor abilities. Model strength varied depending on the PA variable and motor ability entered. Results demonstrate that total PA and meeting current PA guidelines may be of importance for motor ability development and should be investigated further. Other covariates showed stronger associations with motor abilities such as time spent at sports clubs and should be investigated in longitudinal settings to assess the associations with individual motor abilities.
John Kuzmeski, Gillian Weir, Travis Johnson, Matthew Salzano, and Joseph Hamill
This study investigated the differences between 5 commonly used methods to calculate leg stiffness over a range of running velocities. Thirteen male, habitually rearfoot, recreational runners ran on a force instrumented treadmill for a 5-minute running session. Each session consisted of 30-second intervals at 6 progressively faster speeds from 2.5 m·s−1 through 5.0 m·s−1 with each interval speed increasing by 0.5 m·s−1. Two-way within-factors repeated-measures analyses of variance were used to evaluate leg stiffness and length. A one-way repeated-measures analysis of variance was used to evaluate the slope of each trend line of each model across speeds. Pearson correlations were used to compare the relationship between the different computational methods. The results indicated that the direct stiffness methods increased with speed whereas the indirect stiffness methods did not. The direct methods were strongly correlated with each other as were the indirect methods. However, there were no strong correlations between the direct and indirect methods. These differences can be mostly attributed to how each individual stiffness method calculated leg length. It is important for researchers to understand these differences when conducting future studies and comparing past studies.
Chih-Chia Chen, Yonjoong Ryuh, Tony Luczak, and John Lamberth
The purpose of this study was to examine the distance of varying focus of attention for experienced and novice golfers on a golf putting task. Forty-eight experienced and 48 novice golfers were randomized into four attentional focus conditions: control (no instruction), internal (i.e., focus on the arm movement), external proximal (i.e., focus on the golf club), and external distal (i.e., focus on the target) conditions. Performance outcomes (the perceived level of confidence and number of golf putts made) were recorded. Experienced golfers had better performance outcomes than novice golfers. The external proximal focus was specifically beneficial for novice golfers, while experienced golfers had an advantage in both external focus instructions. The external proximal focus might enable a perception-action process for novice golfers to compare the relationship between action planning and the surrounding environment. In addition, the transition to expertise might result in no difference between both external focus instructions for experienced golfers.
Lara Lima Nabuco, Bryan Saunders, Renato André Sousa da Silva, Guilherme Eckhardt Molina, and Caio Eduardo Gonçalves Reis
This study investigated the effects of caffeine mouth rinse on cycling time to exhaustion (TTE) and physiological responses in trained cyclists. In a double-blinded randomized counterbalanced cross-over design, 10 recreationally trained male cyclists (mean ± SD: 32 ± 3 years, 72.8 ± 5.3 kg, 1.78 ± 0.06 m, 13.9% ± 3.3% body fat, peak power output = 289.4 ± 24.7 W) completed two TTE tests cycling at 75% of peak aerobic power following 24 hr of dietary and exercise standardization. Cyclists were administered 25-ml mouth rinses for 5 s containing either 85 mg of caffeine or control (water) every 5 min throughout the exercise tests. No significant improvement in TTE was shown with caffeine mouth rinse compared with control (33:24 ± 12:47 vs. 28:08 ± 10:18 min; Cohen’s dz effect size: 0.51, p = .14). Caffeine mouth rinse had no significant effect on ratings of perceived exertion (p = .31) or heart rate (p = .35) throughout the cycling TTE protocol. These data indicate that a repeated dose of caffeinated mouth rinse for 5 s does not improve cycling TTE in recreationally trained male cyclists. However, these findings should be taken with caution due to the small sample size and blinding ineffectiveness, while further well-design studies with larger samples are warranted.
Ricardo S. Oliveira, Alan R. Barker, Sascha H. Kranen, Florian Debras, and Craig A. Williams
Purpose: In a sample of healthy adolescents, the authors aimed to investigate the effects of high-intensity interval exercise (HIIE) training and detraining on baroreflex sensitivity (BRS) and it’s vascular and autonomic components at rest. Methods: Nineteen volunteers were randomly allocated to (1) 4 weeks HIIE training performed 3 times per week or (2) a control condition with no intervention for the same duration as HIIE training. PRE, POST, and following 2 weeks of detraining resting supine heart rate and blood pressure were measured, and a cross-spectral method (integrated gain [gain in low frequency]) was used to determine BRS gain. Arterial compliance (AC) was assessed as the BRS vascular component. LFgain divided by AC (LFgain/AC) was used as the autonomic determinant of BRS. Results: The HIIE training was completed with 100% compliance. HIIE did not change resting gain in low frequency (LFgain) (P = .66; effect size = 0.21), AC (P = .44; effect size = 0.36), or LFgain/AC (P = .68; effect size = 0.19) compared to control. Conclusion: Four weeks of HIIE training does not change BRS and its autonomic and vascular determinant in a sample of healthy adolescents at rest.
Valderi de Abreu de Lima, Gabriel Ribeiro Cordeiro, Luis Paulo Gomes Mascarenhas, Suzana Nesi França, Juliana Pereira Decimo, Andréia Araújo Porchat de leão, Camila Kapp Fritz, and Neiva Leite
Purpose: The study analyzed the influence of exercise on hypoglycemia episodes postexercise and in the subsequent 24 hours in children and adolescents with type 1 diabetes. Methods: Thirty young people performed the same protocol of physical exercises for 1 hour (Ex1h) and 2 hours (Ex2h) after the administration of insulin. They performed 30 minutes of exercise on a cycle ergometer with a load of 60% of maximal oxygen uptake, interspersed with maximum intensity sprints lasting 10 seconds every 5 minutes. Results: Regarding the occurrence of hypoglycemia, in the 8 hours following the exercises, there was no occurrence in Ex1h (χ 2 = 0.001; P = .0001) and a greater proportion for Ex2h (n = 71 episodes, 53.8%), while Ex1h had a higher number of nocturnal hypoglycemic episodes (n = 60, 71.4%) compared with Ex2h (n = 31, 23.1%, χ 2 = 49.521, P = .0001), Ex1h triggered a lower number of hypoglycemia (n = 84) than Ex2h (n = 134, χ 2 = 11.504, P = .001). There was a greater reduction in the average amount of fast-acting insulin administered the day after Ex1h compared with Ex2h (P = .031). Conclusions: Intermittent exercise performed 1 hour after insulin administration shows a lower risk of hypoglycemia within 8 hours after exercise, as well as a reduction in insulin the following day.
Lauren Q. Higgins, Jeffrey D. Labban, Ruth D. Stout, Jeffrey T. Fairbrother, Christopher K. Rhea, and Louisa D. Raisbeck
Adults (N = 54, 80.78 ± 6.08 years) who reported falling during the previous 12 months participated in a 12-week wobble board training program with internal focus or external focus (EF) instructions. Verbal manipulation checks were performed after training sessions as a self-report of the attentional foci used. The percentage of sessions in which participants reported using an EF (EFSR) was subsequently calculated. Mean velocity and mean power frequency in the anterior–posterior (MVELOAP and MPFAP) and medial–lateral (MVELOML and MPFML) direction were assessed during a 35-s wobble board task at Weeks 0, 6, 12, 13, 16, and 20, with the latter three as retention tests. Piecewise linear growth models estimated treatment effects on individual growth trajectories of MVELOAP and ML and MPFAP and ML during intervention and retention periods. Regardless of condition, MVELOML significantly decreased (π = −.0019, p = .005) and MPFML increased (π = .025, p < .02) during the intervention period. In analyses including interaction terms, participants in the EF group who reported greater EFSR had superior progression of MPFAP during the intervention (π = .0013, p = .025). Verbal manipulation checks suggest a preference for and advantage of EF for facilitating postural control performance and automaticity.
Claudio Quagliarotti, Matteo Cortesi, Giorgio Gatta, Marco Bonifazi, Paola Zamparo, Roberto Baldassarre, Veronica Vleck, and Maria Francesca Piacentini
Purpose : Although wearing a wetsuit while swimming, when permitted, is primarily for safety reasons (ie, to protect against hypothermia), changes in buoyancy, biomechanics, and exercise performance have been reported. This narrative review covers the benefits of different wetsuit models on performance in swimming and triathlon. Methods : A computer search of online databases was conducted to locate relevant published research until March 2021. After the screening process, 17 studies were selected for analysis. Results : Most of the selected studies involved pool swimmers or triathletes completing short or middle distances in a pool while using a full or a long sleeveless wetsuit. Swimming with wetsuit elicited significant improvements in performance (maximum 11%), mainly by decreasing drag and energy cost, by increasing buoyancy, and by affecting technique. Different rates of change in each factor were found according to swimming ability and wetsuit model. In addition, wearing a wetsuit was often rated as uncomfortable by athletes. Conclusions : Although improvement in swimming performance by wearing a wetsuit has been reported in the literature, the amplitude of the improvement remains questionable. The enhancement in swimming performance is attributable merely to improvements in propulsion proficiency and buoyancy, as well as a reduction in drag. The extent to which athletes are familiar with the use of a wetsuit, their swimming ability, and the wetsuit model may play important roles in this improvement. More studies simulating competition and comparing elite versus nonelite athletes are needed.