Search Results

You are looking at 1 - 10 of 1,584 items for :

Clear All
Restricted access

Katherine Elizabeth Black, Alistair David Black and Dane Frances Baker

databases (Web of Science, PubMed, and SPORTDiscus) were searched using the search terms Rugby AND (Nutrition or Diet or Energy OR Macronutrients OR Carbohydrate OR Protein OR Fat). Any additional relevant literature was obtained from the reference lists of the published papers. The inclusion criteria were

Restricted access

Katherine E. Black, Paula M.L. Skidmore and Rachel C. Brown

Endurance events >10 hr are becoming increasingly popular but provide numerous physiological challenges, several of which can be attenuated with optimal nutritional intakes. Previous studies in ultraendurance races have reported large energy deficits during events. The authors therefore aimed to assess nutritional intakes in relation to performance among ultraendurance cyclists. This observational study included 18 cyclists in a 384-km cycle race. At race registration each cyclist’s support crew was provided with a food diary for their cyclist. On completion of the race, cyclists were asked to recall their race food and drink intakes. All food and fluids were analyzed using a computer software package. Mean (SD) time to complete the race was 16 hr 21 min (2 hr 2 min). Mean (SD) energy intake was 18.7 (8.6) MJ, compared with an estimated energy requirement for the race of 25.5 (7.4) MJ. There was a significant negative relationship between energy intake and time taken to complete the race (p = .023, r 2 = −.283). Mean (SD) carbohydrate, fat, and protein intakes were 52 (27), 15.84 (56.43), and 2.94 (7.25) g/hr, respectively. Only carbohydrate (p = .015, r 2 = −.563) and fat intake (p = .037, r 2 = −.494) were associated with time taken to complete the race. This study demonstrates the difficulties in meeting the high energy demands of ultraendurance cycling. The relationship between energy intake and performance suggests that reducing the energy deficit may be advantageous. Given the high carbohydrate intakes of these athletes, increasing energy intake from fat should be investigated as a means of decreasing energy deficits.

Restricted access

Daniel das Virgens Chagas and Luiz Alberto Batista

Adequate motor coordination ability is not only a key factor in children’s general development ( D’Hondt et al., 2013 ); it is also associated with health-related gains ( Chagas & Batista, 2017 ). Previous research has shown motor coordination skills to be negatively associated with body fat

Restricted access

Ulrika Andersson-Hall, Stefan Pettersson, Fredrik Edin, Anders Pedersen, Daniel Malmodin and Klavs Madsen

In order to maximize the adaptive response to endurance training among athletes and/or to promote healthy living in the general population, there has recently been interest in ways to increase the capacity of fat oxidation during exercise. As glycogen stores are limited, a higher reliance on fat

Restricted access

Christopher C. Webster, Jeroen Swart, Timothy D. Noakes and James A. Smith

Low-carbohydrate high-fat (LCHF) diets have gained in popularity among some ultraendurance athletes because they increase rates of fat oxidation during exercise and “spare” muscle glycogen. 1 However, prevailing opinion holds that carbohydrate restriction would compromise exercise performance at

Restricted access

Francisco J. Amaro-Gahete, Lucas Jurado-Fasoli, Alejandro R. Triviño, Guillermo Sanchez-Delgado, Alejandro De-la-O, Jørn W. Helge and Jonatan R. Ruiz

Carbohydrates and fats are the primary substrates oxidized to fuel energy metabolism during exercise. 1 Humans predominantly store carbohydrates as glycogen in skeletal muscle and the liver, and ∼4 g circulating in plasma as glucose. 2 However, these storage depots are limited, whereas human fat

Restricted access

Andrés Pérez, Domingo J. Ramos-Campo, Cristian Marín-Pagan, Francisco J. Martínez-Noguera, Linda H. Chung and Pedro E. Alcaraz

Interestingly, POL has shown to improve VO 2 peak, anaerobic threshold, aerobic efficiency, time to exhaustion during an incremental test, 14 finishing time in 10-km races, 13 and running economy in ultrarunners. 9 In addition, fat metabolism has a key role in endurance events. 15 The maximal fat oxidation

Restricted access

Mark Elisabeth Theodorus Willems, Mehmet Akif Şahin and Matthew David Cook

reported health benefits of regular intake of green tea such as a reduced risk for some cancers ( Guo et al., 2017 ) and cardiovascular and ischemic-related diseases ( Pang et al., 2016 ). Green tea has also been implicated in body weight management ( Janssens et al., 2016 ) by promoting fat oxidation

Restricted access

Christopher L. Melby, Kristen L. Osterberg, Alyssa Resch, Brenda Davy, Susan Johnson and Kevin Davy

Thirteen physically active, eumenorrheic, normal-weight (BMI ≤ 25 kg/m2) females, aged 18–30 years, completed 4 experimental conditions, with the order based on a Latin Square Design: (a) CHO/Ex: moderate-intensity exer-· cise (65% V̇O2peak) with a net energy cost of ~500 kcals, during which time the subject consumed a carbohydrate beverage (45 g CHO) at specific time intervals; (b) CHO/NoEx: a period of time identical to (a) but with subjects consuming the carbohydrate while sitting quietly rather than exercising; (c) NoCHO/ Ex: same exercise protocol as condition (a) during which time subjects consumed a non-caloric placebo beverage; and (d) NoCHO/NoEx: same as the no-exercise condition (b) but with subjects consuming a non-caloric placebo beverage. Energy expenditure, and fat and carbohydrate oxidation rates for the entire exercise/sitting period plus a 90-min recovery period were determined by continuous indirect calorimetry. Following recovery, subjects ate ad libitum amounts of food from a buffet and were asked to record dietary intake during the remainder of the day. Total fat oxidation (exercise plus recovery) was attenuated by carbohydrate compared to placebo ingestion by only ~4.5 g. There was a trend (p = .08) for a carbohydrate effect on buffet energy intake such that the CHO/Ex and CHO/NoEx energy intakes were lower than the NoCHO/Ex and NoCHO/NoEx energy intakes, respectively (mean for CHO conditions: 683 kcal; NoCHO conditions: 777 kcal). Average total energy intake (buffet plus remainder of the day) was significantly lower (p < .05) following the conditions when carbohydrate was consumed (CHO/Ex = 1470 kcal; CHO/NoEx = 1285 kcal) compared to the noncaloric placebo (NoCHO/Ex =1767 kcal; NoCHO/ NoEx = 1660 kcal). In conclusion, in young women engaging in regular exercise, ingestion of 45 g of carbohydrate during exercise only modestly suppresses total fat oxidation during exercise. Furthermore, the ingestion of carbohydrate with or without exercise resulted in a lower energy intake for the remainder of the day

Restricted access

Jace A. Delaney, Heidi R. Thornton, Tannath J. Scott, David A. Ballard, Grant M. Duthie, Lisa G. Wood and Ben J. Dascombe

High levels of lean mass are important in collision-based sports for the development of strength and power, which may also assist during contact situations. While skinfold-based measures have been shown to be appropriate for cross-sectional assessments of body composition, their utility in tracking changes in lean mass is less clear.


To determine the most effective method of quantifying changes in lean mass in rugby league athletes.


Body composition of 21 professional rugby league players was assessed on 2 or 3 occasions separated by ≥6 wk, including bioelectrical impedance analysis (BIA), leanmass index (LMI), and a skinfold-based prediction equation (SkF). Dual-X-ray absorptiometry provided a criterion measure of fat-free mass (FFM). Correlation coefficients (r) and standard errors of the estimate (SEE) were used as measures of validity for the estimates.


All 3 practical estimates exhibited strong validity for cross-sectional assessments of FFM (r > .9, P < .001). The correlation between change scores was stronger for the LMI (r = .69, SEE 1.3 kg) and the SkF method (r = .66, SEE = 1.4 kg) than for BIA (r = .50, SEE = 1.6 kg).


The LMI is probably as accurate in predicting changes in FFM as SkF and very likely to be more appropriate than BIA. The LMI offers an adequate, practical alternative for assessing in FFM among rugby league athletes.