Nutritional Adequacy and Physical Performance in Female Adolescent Hockey Players

This thesis presents research to document the physical activity, training and match demands, nutritional intake, and dietary habits in female adolescent hockey players. In Study 1, 24 female adolescent hockey player’s body mass and stature were measured and developmental age calculated and compared with measures of physical performance. Participants were average developing but 90% were still growing. Physical performance measures were above population means, in line with other studies in young athletes but below elite adult female hockey players. From all measures it was concluded that adolescent female hockey players at the bottom of the England hockey selection pyramid would fit the IOC definition of an adolescent athlete. Study 2 used GPS and heart rate monitors to quantify physical demands of 45 players in U16 League Games. Distance covered and pitch time were comparable to International U16/U17 and sub-elite adult games, but the intensity of play was lower. From this study coaches working with adolescent female hockey players would be advised focus on the intensity of play in preparation for higher and adult leagues. In Study 3, 24 female adolescent hockey players completed a 4-day self-report food and physical activity diary. Total energy, carbohydrate, fruit and vegetable portions and fibre were all lower than guidelines, and saturated fat and sugar intake were higher than recommended. Protein intake was adequate but poorly distributed across the day. On the back of this data, in line with the National Diet and Nutrition Surveys (2012-2020), practitioners working with this age group should initially focus on population healthy eating advice, increasing fruit and vegetable intake and ensuring adequate protein availability across the day. Study 4 used an online questionnaire to document habitual eating behaviour and physical activity levels in 162 female adolescent hockey players. Participants played 21 different sports. Physical activity was classified as moderate overall and high in the evenings and weekends. Most participants ate breakfast and a cooked lunch, but there was evidence that eating behaviour was impacted by sports participation and this should be taken into account when planning sports training schedules and nutrition education. Study 5 concurrently measured physical activity (accelerometer and GPS), nutritional intake (food diary), nutrition knowledge and eating behaviour (surveys) in 29 female adolescent hockey players over seven days. The regular sports training and competition contributed to players high energy expenditure, which was not matched by energy intake. Dietary quality was poor with high intake of saturated fat and added sugar and low fibre intake. In summary, the research in this thesis presents novel data on anthropometric and physiological characteristics, training and match loads, physical activity, nutritional intake, and dietary habits of female adolescent hockey players which can be used to inform evidence-based guidance for players, parents, schools, and coaches

Food for thought: Dietary nootropics for the optimisation of military operators cognitive performance

Nootropics are compounds that enhance cognitive performance and have been highlighted as a medium-term human augmentation technology that could support soldier performance. Given the differing ethical, safety, and legal considerations associated with the pharmaceutical subset of nootropics, this analysis focuses on dietary supplementation which may enhance cognition during training and operations. Numerous supplements have been investigated as possible nootropics, however research is often not context specific or of high quality, leading to questions regarding efficacy. There are many other complex cofactors that may affect the efficacy of any dietary nootropic supplement which is designed to improve cognition, such as external stressors (e.g., sleep deprivation, high physical workloads), task specifics (e.g., cognitive processes required), and other psychological constructs (e.g., placebo/nocebo effect). Moreover, military population considerations, such as prior nutritional knowledge and current supplement consumption (e.g., caffeine), along with other issues such as supplement contamination should be evaluated when considering dietary nootropic use within military populations. However, given the increasing requirement for cognitive capabilities by military personnel to complete role-related tasks, dietary nootropics could be highly beneficial in specific contexts. Whilst current evidence is broadly weak, nutritional nootropic supplements may be of most use to the military end user, during periods of high military specific stress. Currently, caffeine and L-tyrosine are the leading nootropic supplements candidates within the military context. Future military specific research on nootropics should be of high quality and use externally valid methodologies to maximise the translation of research to practice

Effects of CurraNZ, a New Zealand blackcurrant extract during 1 hour of treadmill running in female and male Marathon des Sables Athletes in hot conditions: two case studies

Four weeks before competition in the 2023 Marathon des Sables, a 6 stage, ~250 km running event in the Sahara Desert, we examined effects of 7-day intake of New Zealand blackcurrant extract (210 mg anthocyanins per day) on 1 h treadmill running-induced physiological and metabolic responses in the heat (~34°C, relative humidity: ~30%) in a non-acclimatized amateur female and male athlete (age: 23, 38 yrs, BMI: 24.2, 28.4 kg·m-2, body fat%: 29.2, 18.8%, V ̇O2max: 50.1, 52.1 mL·kg-1·min-1). During the 1 h run at 50%V ̇O2max (speed female: 7.3, male: 7.5 km·h-1), indirect calorimetry was used and heart rate recorded at 15-min intervals with core temperature monitoring (0.05 Hz). The 1 h runs were 3 h after a light breakfast and 2 h after intake of the final dose of New Zealand blackcurrant extract with water allowed ad libitum during the run. With the New Zealand blackcurrant extract, there were no effects in the female athlete. The respiratory exchange ratio (RER) of the female athlete in the non-supplement control condition was 0.77±0.01, indicating existing ~77% contribution of fat oxidation to the energy requirements. In the male athlete during 1 h of running, fat oxidation was higher by 21% (p<0.01), carbohydrate oxidation was 31% lower (p=0.05), RER was 0.03 units lower (p=0.04) and core temperature was 0.4°C lower (p<0.01) with no differences for heart rate, minute ventilation, oxygen uptake and carbon dioxide production for the New Zealand blackcurrant condition compared to the non-supplement control condition. Seven-day intake of New Zealand blackcurrant extract (210 mg anthocyanins per day) provided beneficial physiological and metabolic responses during exertional heat stress by 1 h of indoor (~34°C) treadmill running in a male Marathon des Sables athlete 4 weeks before competition. Future work is required to address whether New Zealand blackcurrant provide a nutritional ergogenic effect for Marathon des Sables athletes during long-duration running in the heat combined with personalized nutrition

Beneficial Physiological and Metabolic Effects with Acute Intake of New Zealand Blackcurrant Extract during 4 h of Indoor Cycling in a Male Ironman Athlete: A Case Study

New Zealand blackcurrant (NZBC) is known to alter exercise-induced physiological and metabolic responses with chronic (i.e., 7 days) dosing. We examined the effects of acute intake of New Zealand blackcurrant (NZBC) extract on 4 h indoor cycling-induced physiological and metabolic responses in a male amateur Ironman athlete (age: 49 years; BMI: 24.3 kg·m−2; V˙O2max: 58.6 mL·kg−1·min−1; maximal aerobic power: 400 W; history: 14 Ironman events in 16 years) three weeks before competition. Indirect calorimetry was used and heart rate was recorded at 30 min intervals during 4 h indoor (~22.4 °C, relative humidity: ~55%) constant power (165 W) cycling on a Trek Bontrager connected to a Kickr smart trainer. Blood lactate and rating of perceived exertion (RPE) were taken at 60 min intervals. Study was a single-blind placebo-controlled study with capsules (4 × 105 mg anthocyanins) taken 2 h before starting the 4 h of cycling. Water was allowed ad libitum with personalised consumption of gels [a total of eight with three with caffeine (100 mg)], two bananas and 8 × electrolyte capsules (each 250 mg sodium and 125 mg potassium) at personalised time-points. With NZBC extract (CurraNZ), during 4 h of cycling (mean of 8 measurements), minute ventilation was 8% lower than placebo. In addition, there was no difference for oxygen uptake, with carbon dioxide production found to be 4% lower with NZBC extract. With the NZBC extract, the ventilatory equivalents were lower for oxygen and carbon dioxide by 5.5% and 3.7%; heart rate was lower by 10 beats·min−1; lactate was 40% different with lower lactate at 2, 3 and 4 h; RPE was lower at 2, 3 and 4 h; and carbohydrate oxidation was 11% lower. With NZBC extract, there was a trend for fat oxidation to be higher by 13% (p = 0.096), with the respiratory exchange ratio being lower by 0.02 units. Acute intake of New Zealand blackcurrant extract (420 mg anthocyanins) provided beneficial physiological and metabolic responses during 4 h of indoor constant power cycling in a male amateur Ironman athlete 3 weeks before a competition. Future work is required to address whether acute and chronic dosing strategies with New Zealand blackcurrant provide a nutritional ergogenic effect for Ironman athletes to enhance swimming, cycling and running performance

Effects of CurraNZ, a New Zealand Blackcurrant Extract during 1 Hour of Treadmill Running in Female and Male Marathon des Sables Athletes in Hot Conditions: Two Case Studies

Four weeks before competition in the 2023 Marathon des Sables, a 6-stage, ~250 km running event in the Sahara Desert, we examined the effects of a 7-day intake of New Zealand blackcurrant extract (210 mg anthocyanins per day) on 1 h treadmill running-induced physiological and metabolic responses in the heat (~34 °C, relative humidity: ~30%) in non-acclimatized amateur female and male athletes (age: 23, 38 yrs, BMI: 24.2, 28.4 kg·m−2, body fat%: 29.2, 18.8%, V˙O2max: 50.1, 52.1 mL·kg−1·min−1). During the 1 h run at 50%V˙O2max (speed female: 7.3, male: 7.5 km·h−1), indirect calorimetry was used, and heart rate was recorded at 15 min intervals with core temperature monitoring (0.05 Hz). The 1 h runs took place 3 h after a light breakfast and 2 h after intake of the final dose of New Zealand blackcurrant extract with water allowed ad libitum during the run. The New Zealand blackcurrant extract had no effects on the female athlete. The respiratory exchange ratio (RER) of the female athlete in the non-supplement control condition was 0.77 ± 0.01, indicating an existing ~77% contribution of fat oxidation to the energy requirements. In the male athlete, during 1 h of running, fat oxidation was higher by 21% (p p = 0.05), RER was 0.03 units lower (p = 0.04), and core temperature was 0.4 °C lower (p < 0.01) with no differences for heart rate, minute ventilation, oxygen uptake, and carbon dioxide production for the New Zealand blackcurrant condition compared to the non-supplement control condition. Seven-day intake of New Zealand blackcurrant extract (210 mg anthocyanins per day) provided beneficial physiological and metabolic responses during exertional heat stress by 1 h of indoor (~34 °C) treadmill running in a male Marathon des Sables athlete 4 weeks before competition. Future work is required to address whether New Zealand blackcurrant provides a nutritional ergogenic effect for Marathon des Sables athletes during long-duration running in the heat combined with personalized nutrition