Dionne A. Noordhof, Xanne A.K. Janse de Jonge, Anthony C. Hackney, Jos J. de Koning, and Øyvind Sandbakk
James A. Betts
Oliver J. Peacock, Javier T. Gonzalez, Simon P. Roberts, Alan Smith, Scott Drawer, and Keith A. Stokes
Ketone ingestion can alter metabolism but effects on exercise performance are unclear, particularly with regard to the impact on intermittent-intensity exercise and team-sport performance. Nine professional male rugby union players each completed two trials in a double-blind, randomized, crossover design. Participants ingested either 90 ± 9 g carbohydrate (CHO; 9% solution) or an energy matched solution containing 20 ± 2 g CHO (3% solution) and 590 mg/kg body mass β-hydroxybutyrate monoester (CHO + BHB-ME) before and during a simulated rugby union-specific match-play protocol, including repeated high-intensity, sprint and power-based performance tests. Mean time to complete the sustained high-intensity performance tests was reduced by 0.33 ± 0.41 s (2.1%) with CHO + BHB-ME (15.53 ± 0.52 s) compared with CHO (15.86 ± 0.80 s) placebo (p = .04). Mean time to complete the sprint and power-based performance tests were not different between trials. CHO + BHB-ME resulted in blood BHB concentrations that remained >2 mmol/L during exercise (p < .001). Serum lactate and glycerol concentrations were lower after CHO + BHB-ME than CHO (p < .05). Coingestion of a BHB-ME with CHO can alter fuel metabolism (attenuate circulating lactate and glycerol concentrations) and may improve high-intensity running performance during a simulated rugby match-play protocol, without improving shorter duration sprint and power-based efforts.
Lindsay B. Baker, Michelle A. King, David M. Keyes, Shyretha D. Brown, Megan D. Engel, Melissa S. Seib, Alexander J. Aranyosi, and Roozbeh Ghaffari
The purpose of this study was to compare a wearable microfluidic device and standard absorbent patch in measuring local sweating rate (LSR) and sweat chloride concentration ([Cl−]) in elite basketball players. Participants were 53 male basketball players (25 ± 3 years, 92.2 ± 10.4 kg) in the National Basketball Association’s development league. Players were tested during a moderate-intensity, coach-led practice (98 ± 30 min, 21.0 ± 1.2 °C). From the right ventral forearm, sweat was collected using an absorbent patch (3M Tegaderm™ + Pad). Subsequently, LSR and local sweat [Cl−] were determined via gravimetry and ion chromatography. From the left ventral forearm, LSR and local sweat [Cl−] were measured using a wearable microfluidic device and associated smartphone application-based algorithms. Whole-body sweating rate (WBSR) was determined from pre- to postexercise change in body mass corrected for fluid/food intake (ad libitum), urine loss, and estimated respiratory water and metabolic mass loss. The WBSR values predicted by the algorithms in the smartphone application were also recorded. There were no differences between the absorbent patch and microfluidic patch for LSR (1.25 ± 0.91 mg·cm−2·min−1 vs. 1.14 ±0.78 mg·cm−2·min−1, p = .34) or local sweat [Cl−] (30.6 ± 17.3 mmol/L vs. 29.6 ± 19.4 mmol/L, p = .55). There was no difference between measured and predicted WBSR (0.97 ± 0.41 L/hr vs. 0.89 ± 0.35 L/hr, p = .22; 95% limits of agreement = 0.61 L/hr). The wearable microfluidic device provides similar LSR, local sweat [Cl−], and WBSR results compared with standard field-based methods in elite male basketball players during moderate-intensity practices.
Piyawat Katewongsa, Panya Choolers, Pairoj Saonuam, and Dyah Anantalia Widyastari
Purpose: This study aims to examine the effectiveness of a whole-of-school approach by using the 4PC model (Active Policy, Active People, Active Program, Active Place, and Active Classroom) in improving physical activity and reducing sedentary behavior of school children in Thailand. Method: We employed a quasi-experimental cohort design in which the intervention group was exposed to the 4PC model and control schools performed their regular routine. We followed the same students from 10 participating schools over a 2-year academic period (2017–2019) from primary school Grades 4–6. A total of 119 of 184 students in the intervention group, and 173 of 254 students in the control group were present in all five rounds of data collection and are included in the analysis. Results: Compared to students in the control group without the 4PC exposure, students in the intervention group accumulated an additional 19–25 min of physical activity time and experienced a 31-min reduction in sedentary time. Conclusion: As a whole-of-school approach, the 4PC model was effective in increasing physical activity and reducing sedentary behavior of primary school children in Thailand.