Burns, Stephen Francis

Purpose: Nutrition education programmes are often created to improve dietary intake in athletes. Unfortunately, the inconsistent link between nutrition knowledge and dietary behavior suggests that nutrition knowledge may not be a key influencer of dietary behavior. The Knowledge–Attitude–Behavior (KAB) model has been used in nutrition education although studies that evaluated this model were largely compromised by poorly constructed instruments and methodological discrepancies.

Method: To improve understanding of the model, a Nutrition Knowledge Questionnaire (NKQ) and Athlete’s Perspective on Nutrition (APN) instrument was developed using the theory of planned behavior as its theoretical framework. Validity and reliability were examined for 193 Sports Science students and 11 elite netballers. Content and face validity of the 48-item NKQ was confirmed by expert sport dietitians. Discriminant validity of the NKQ and factorial validity of the APN was established. Both instruments demonstrated acceptable internal consistency and good test-retest reliability. The final instruments were administered to elite athletes in a pilot study to understand the KAB model.

Results: Correlation between nutrition knowledge and dietary behavior was significant (r = .811, p = .01). Nutrition knowledge was a positive predictor of netballers’ dietary behavior (β = .8, t(2) = 3.899, p = .005) but attitude was not (β = −.097, t(2) = −.471, p = .65).

Conclusion: Two psychometrically sound instruments developed in this study can be used to measure nutrition knowledge and attitude in an Asian group of athletes. The pilot study with athletes showed that nutrition knowledge predicted dietary behavior.

This study investigated the effects of the timing of caffeine (3 mg/kg body mass) ingestion on three-point shooting accuracy and other performance parameters during a basketball exercise simulation test (BEST). Eighteen college basketball players (mean ± SD: age = 24.4 ± 1.5 years, height = 181.7 ± 9.5 cm, body mass = 80.9 ± 13.2 kg) underwent one familiarization trial and three main conditions in a randomized order: (a) placebo (maltodextrin) and placebo, (b) caffeine and placebo, and (c) placebo and caffeine. Participants ingested either the placebo or caffeine pill 75 and 15 min before performing four quarters of the BEST and a three-point shooting protocol. During each quarter, participants completed 16 rounds of the BEST and ten three-point shots. Vertical jump height, 6 m sprint timing, BEST completion timing, three-point shooting accuracy, heart rate, rate of perceived exertion, blood glucose, blood lactate, and psychological measures pertaining to performance were measured. The BEST completion timing differed among conditions (placebo and placebo = 26.4 ± 2.0 s, caffeine and placebo = 25.8 ± 2.0 s, placebo and caffeine = 25.9 ± 2.1 s; p = .031) but not three-point shooting accuracy (placebo and placebo = 12.33 ± 4.10; caffeine and placebo = 12.61 ± 2.81; placebo and caffeine = 11.67 ± 3.77; p = .648), vertical jump height, or sprint times. Manipulating ingestion timing of caffeine did not improve three-point shooting accuracy, vertical jump height, or 6 m sprint timings, but caffeine can improve performance times during simulated basketball exercise irrespective of ingestion timing.

The widespread benefits of physical activity in enhancing health and lowering the risk of non-communicable chronic diseases are well established across populations globally. Nevertheless, the prevalence of several lifestyle-related chronic diseases, including cardiovascular disease, varies markedly across countries and ethnicities. Direct ethnic comparative studies on the health benefits of physical activity are sparse and evidence-based physical activity guidelines are not ethnicity-specific. Indeed, physical activity guidelines in some Asian countries were developed primarily based on data from Western populations even though the magnitude of potential benefit may not be the same among different ethnic groups. Unfavorable diurnal perturbations in postprandial triglycerides and glucose are risk factors for cardiovascular disease. This narrative review summarizes differences in these risk factors primarily between individuals of Asian and white European descent but also within different Asian groups. Moreover, the variable effects of physical activity on mitigating risk factors among these ethnic groups are highlighted along with the underlying metabolic and hormonal factors that potentially account for these differences. Future ethnic comparative studies should include investigations in understudied ethnic groups, such as those of East Asian origin, given that the effectiveness of physical activity for ameliorating cardiovascular disease varies even among Asian groups.

Background Good nutrition, regular physical activity, and adequate sleep are important for promoting health. However, it is not well characterized how these lifestyle behaviours are associated with mood at the start of school days. Aim To identify the weekday health-related behaviours (breakfast intake, physical activity, and sleep) of Singaporean adolescents and explore their associations with mood at the beginning of the school morning. Methods 365 adolescents (52.3% boys, 47.7% girls) aged 14–19 years (M = 16.9, SD = 1.3 years) completed a survey set on breakfast habits, physical activity participation, sleep duration, and mood. Results More than one-third (38.6%) of participants never (15.0%) or irregularly (23.6%) consumed breakfast on weekdays. Adolescents consuming breakfast irregularly reported significantly higher negative mood scores than regular breakfast consumers (p = .002; d = .404). Almost two-thirds (64.1%) of adolescents did <60 min of moderate-to-vigorous physical activity (MVPA) on weekdays and reported lower positive morning mood scores than those who ≥60 min of MVPA (p = .014; d = .284). Although most (88.3%) adolescents slept <8 h each night, sleep duration was not related to either positive mood or negative mood. Conclusion The present study suggests that eating breakfast on a regular basis and completing for ≥60 min of weekday MVPA are useful behaviours to start school days in a better mood. Parents and health educators should recognise the importance of establishing these habits and support students by instigating practical approaches so they can achieve a regular breakfast intake and physical activity engagement.

Dietary nitrate supplementation has shown promising ergogenic effects on endurance exercise. However, at present there is no systematic analysis evaluating the effects of acute or chronic nitrate supplementation on performance measures during high-intensity interval training (HIIT) and sprint interval training (SIT). The main aim of this systematic review and meta-analysis was to evaluate the evidence for supplementation of dietary beetroot—a common source of nitrate—to improve peak and mean power output during HIIT and SIT. A systematic literature search was carried out following PRISMA guidelines and the PICOS framework within the following databases: PubMed, ProQuest, ScienceDirect, and SPORTDiscus. Search terms used were: ((nitrate OR nitrite OR beetroot) AND (HIIT or high intensity or sprint interval or SIT) AND (performance)). A total of 17 studies were included and reviewed independently. Seven studies applied an acute supplementation strategy and ten studies applied chronic supplementation. The standardised mean difference for mean power output showed an overall trivial, non-significant effect in favour of placebo (Hedges’ g = −0.05, 95% CI −0.32 to 0.21, Z = 0.39, p = 0.69). The standardised mean difference for peak power output showed a trivial, non-significant effect in favour of the beetroot juice intervention (Hedges’ g = 0.08, 95% CI -0.14 to 0.30, Z = 0.72, p = 0.47). The present meta-analysis showed trivial statistical heterogeneity in power output, but the variation in the exercise protocols, nitrate dosage, type of beetroot products, supplementation strategy, and duration among studies restricted a firm conclusion of the effect of beetroot supplementation on HIIT performance. Our findings suggest that beetroot supplementation offers no significant improvement to peak or mean power output during HIIT or SIT. Future research could further examine the ergogenic potential by optimising the beetroot supplementation strategy in terms of dosage, timing, and type of beetroot product. The potential combined effect of other ingredients in the beetroot products should not be undermined. Finally, a chronic supplementation protocol with a higher beetroot dosage (>12.9 mmol/day for 6 days) is recommended for future HIIT and SIT study.

Far infrared radiation (FIR) within the wavelength range of 4–14 μm can offer human health benefits, such as improving blood flow. Therefore, additives that emit far infrared radiation have the potential to be incorporated into polymer/fabric matrices to develop textiles that could promote health. In this study, biochar derived from candlenuts and pyrolyzed with activated carbon (AC) was incorporated into polypropylene (PP) films and investigated for its potential as a health-promoting textile additive. The properties of biochar were compared with other far infrared (FIR) emitting additives such as hematite, Indian red ochre, and graphene. The addition of biochar increased FIR emissivity to 0.90, which is 9% higher than that of pristine PP. Additionally, biochar enhanced UV and near-infrared (NIR) blocking capabilities, achieving an ultra-protection factor (UPF) of 91.41 and NIR shielding of 95.85%. Incorporating 2 wt% biochar resulted in a 3.3-fold higher temperature increase compared to pristine PP after 30 s of exposure to an FIR source, demonstrating improved heat retention. Furthermore, the ability to achieve the lowest thermal effusivity among other additives supports the potential use of biochar-incorporated fabric as a warming material in cold climates. The tensile properties of PP films with biochar were superior to those with other additives, potentially contributing to a longer product lifespan. Additionally, samples with red ochre exhibited the highest FIR emissivity, while samples with hematite showed the highest capacity for UV shielding.

Purpose This study examined the thermoregulatory response and ergogenic effects of ice slurry (ICE) ingestion in hot environments with high and low relative humidity (RH). Methods Eight males completed four trials in a crossover manner in dry (DRY: 34.7 ± 0.2 °C, 38 ± 2%RH) and humid heat (HUM: 34.8 °C ± 0.2 °C, 80 ± 1%RH). They ingested 8.0 g·kg−1 of ICE (0.0 °C) or 37.5 °C water (CON) during 30 min before exercise, and three aliquots (3.2 g·kg−1) of ICE or CON during 45-min cycling at 50%V˙ O2peak, followed by cycling to exhaustion at 80%V˙ O2peak (TTE). Body core temperature (Tcore), mean skin temperature (Tsk), heart rate (HR), thermal comfort, thermal sensation and rating of perceived exertion (RPE) were measured. Results Relative to CON, ICE improved TTE by 76.5 ± 96.5% in HUM and 21.3 ± 44.9% in DRY (p = 0.044). End-exercise Tcore was lower in ICE versus CON in DRY (37.8 ± 0.4 °C versus 38.1 ± 0.3 °C, p = 0.005) and HUM (38.8 ± 0.4 °C versus 39.3 ± 0.6 °C, p = 0.004). ICE decreased HR, heat storage and heat strain index only in DRY (p < 0.001–0.018). ICE improved thermal sensation and comfort in DRY and HUM (p < 0.001–0.011), attenuated RPE in HUM (p = 0.012) but not in DRY (p = 0.065). Conclusion ICE tended to benefit performance in humid heat more than in dry heat. This is likely due to the reduced extent of hyperthermia in dry heat and the relative importance of sensory inputs in mediating exercise capacity.

This study investigated the efficacy of ingesting an oral rehydration solution (DD) that has a high electrolyte concentration after exercise on fluid balance and cycling performance in comparison with a sports drink (SD) and water (WA). Nine healthy males aged 24 ± 2 years (mean ± SD), with peak oxygen uptake (VO₂ peak) 55 ± 6 mL·kg⁻¹·min⁻¹ completed three experimental trials in a randomised manner ingesting WA, SD (carbohydrates: 62 g·L⁻¹, sodium: 31 ± 3 mmol·L⁻¹) or DD (carbohydrates: 33 g·L⁻¹, sodium: 60 ± 3 mmol·L⁻¹). On all trials, fluid was ingested during 75 min cycling at 65% VO₂ peak (temperature: 30.4 ± 0.3 °C, relative humidity: 76 ± 1%, simulated wind speed: 8.0 ± 0.6 m·s⁻¹) and during 2 h of recovery (temperature: 23.0 ± 1.0 °C, relative humidity: 67 ± 2%), with the total volume equivalent to 150% of sweat loss during the ride. A 45 min pre-load cycling time trial at a 65% VO₂ peak followed by a 20 km time trial was conducted after a further 3 h of recovery. Fluid retention was higher with DD (30 ± 15%) than WA (−4 ± 19%; p < 0.001) and SD (10 ± 15%; p = 0.002). Mean ratings of palatability were similar among drinks (WA: 4.25 ± 2.60; SD: 5.61 ± 1.79; DD: 5.40 ± 1.58; p = 0.33). Although time trial performance was similar across all three trials (WA: 2365 ± 321 s; SD: 2252 ± 174 s; DD: 2268 ± 184 s; p = 0.65), the completion time was faster in eight participants with SD and seven participants with DD than with WA. Comparing SD with DD, completion time was reduced in five participants and increased in four participants. DD was more effective at restoring the fluid deficit during recovery from exercise than SD and WA without compromising the drink’s palatability with increased sodium concentration. Most individuals demonstrated better endurance exercise time trial performance with DD and SD than with WA.

The objective of the current study was to examine the trends of physical activity (PA) and sedentary behaviour (SB) of adolescents in Singapore with two datasets 15 years apart (2006 and 2021). A total sample of 1075 secondary students (mean age = 14.91 ± 0.43 years old) from 15 schools in Singapore took part in the study. A seven-day recall Self-administered Physical Activity Checklist (SAPAC) questionnaire was used to capture time spent on the internet/computer, gaming, homework, reading, sitting and talking/listening to music, telephone, television watching, and PA. Results showed that the 2021 sample spent significantly more time on gaming, homework, sit and talk/listening to music, phone, and PA compared to the 2006 sample, while time spent watching television was significantly lower than the 2006 sample. Both datasets found PA had low or close to zero correlations with all the seven SB, however, the patterns of correlations were different in the two datasets, indicating changes in the trends of SB and PA. Cluster analysis found similar cluster profiles in the two samples but the cluster proportions for certain profiles were different from the two datasets. Significant sex differences were also found in the cluster compositions. Overall, this study shows that PA and SB trends of adolescents have changed significantly.