Andrew T. Hulton

Energy expenditure in the Race Across America (RAAM).

Energy Expenditure was measured with doubly labelled water technique during heavy sustained exercise with an official finishing team in the Race Across America. Energy Intake was also calculated to produce an energy balance for the race. A team of 4 cyclists (Mean +/-SD age: 37+4 yr; body height: 182+8 cm; body mass: 80.8+6.6 kg) completed the race in a relay fashion. The team completed the race in 6 days 10 h and 51 min. Total mean energy expenditure was found to be 43,401 kcals (181,711 kJ) with a mean daily energy expenditure of 6,420 kcals (26,879 kJ). Total mean energy intake from all food and drink consumed was calculated at 29,506 kcals (123,536 kJ) with a mean daily energy intake of 4 918 kcals (20,591 kJ). This resulted in a total mean energy deficit of 13,878 kcals (58,104 kJ) with a mean daily energy deficit of 1,503 kcals (6,293 kJ). The high energy expenditure highlights the need for correct and practical dietary strategies and challenges nutritionists to devise high energy diets that not only contain the correct macronutrient balance, but are also palatable to the cyclists, thus encouraging a high energy intake.

Manipulation of exercise to rest ratio within set duration on physical and technical outcomes during small-sided games in elite youth soccer players

Training practices for elite soccer players should take into account specific technical, tactical and physical components. As a consequence of these demands small-sided games (SSGs) have become a popular conditioning tool that replicate the demands encountered during match play. The aim of this investigation was to examine how the manipulation of exercise to rest ratio, within the same overall duration, affected both physical and technical outcomes during SSGs in elite youth soccer. Twelve elite youth soccer players participated in three variations of eight minute 6v6 SSGs. The three variations included eight minutes continuous, 2×4min and 4×2min. Players perceived the continuous 8min block as the hardest (4.5±1.5AU), followed by the 2×4min (3.9±1.4AU) and the 4×2min (3.3±1.4AU), although no difference in mean HR or physical measures via GPS analysis between SSGs was evident. From the technical perspective, only goals scored reached significance, with post hoc analysis identifying the number of goals scored were significantly higher during the 4×2min and 2×4min SSGs compared to 8min continuous block. These results show that subjective ratings of exertion differed between conditions, but only minor technical manipulations were observed by adjusting work to rest ratios, with no significant effect on physical performance.

A Unique Case Series of Novel Biomarkers of Cardiac Damage in Cyclists Completing the 4800 km Race Across America (RAAM)

Prolonged strenuous exercise is associated with the appearance of biomarkers of cardiac cell damage and a decline in cardiac function during recovery. Few studies have assessed repeated bouts of prolonged exercise and whether this results in further biomarker accumulation and greater dysfunction. Further, it may be useful to describe the changes in a range of biomarkers that may provide additional insight into the clinical significance of cardiac biomarker release. Four highly trained cyclists completed the 4800 km Race Across America (RAAM) in 7 days. Venous blood samples and echocardiograms were taken prior to, every 24 hours during and immediately after the RAAM. Venous blood was analysed for cardiac troponin I (cTnI), creatine kinase MB (CK-MB), fatty acid binding protein (HFABP), glycogen phosphorylase BB (GPBB) and N-Terminal Brain Natriuretic Peptide (NTproBNP). Echocardiograms allowed analysis of septal, left ventricular free wall and right ventricular free wall tissue velocities during systole and diastole. Before the RAAM cTnI levels were below the assay detection level (0.02 ng.ml⁻¹). In three riders cTnI peaked on day one (0.03 ng.ml⁻¹) and returned below detection levels post race. In the 4th rider cTnI peaked on day 5 (0.08 ng.ml⁻¹) and was still elevated post-race. Both CK-MB and H-FABP were increased during the RAAM in all 4 cyclists. In three riders H-FABP peaked on day one (3.49 to 5.09 ng.ml⁻¹) and declined over the rest of the RAAM. In the final rider H-FABP peaked on day two (5.90 ng.ml⁻¹) and then dropped back to baseline by the post-RAAM assessment. Interestingly, changes in H-FABP mirrored, temporally, changes in CK-MB in places and this may reflect an association with skeletal muscle damage. Data for GPBB value to (2.9 - 149.6 ng.ml⁻¹) and NTproBNP value to (27.3 - 310.0 ng.L⁻¹) were variable but again was elevated in all riders during the course of the RAAM. Changes in ventricular wall tissue velocities were minor and not cumulative. Peak atrial diastolic tissue velocity in the left ventricular free wall increased (P < 0.05) from 11 to 18 cm.s⁻¹ over the last two race days but this did not significantly impact the ratio of early to late diastolic wall motion. Cardiac biomarkers were elevated during the completion of the RAAM in all 4 cyclist but changes were not cumulative which suggest that the hearts of the cyclists coped well with the extreme cardiac work demanded by this ultra-endurance exercise challenge.

Effects of GI meals on intermittent exercise.

Pre-exercise meals or single foods containing low glycaemic index (LGI) carbohydrates (CHO) have been shown to enhance performance prior to prolonged steady state exercise compared to high glycaemic index (HGI) CHO. This study investigated the impact of HGI and LGI pre-exercise meals on intermittent high intensity exercise. Nine male recreational football players performed a football specific protocol followed by a 1 km time trial 3.5 h after ingesting 1 of 2 isoenergetic test meals (HGI: 870.3 kcal, LGI: 889.5 kcal), which were either HGI (GI: 80) or LGI (GI: 44). Blood glucose, fatty acids (FA), glycerol, β-hydroxybutyrate, lactate and insulin were assessed before, during, and after the exercise bout, whilst rates of CHO and fat oxidation were determined at 4 time points during the protocol. No significant differences were found for the 1 km time trial (LGI: 210.2 ± 19.1 s: HGI: 215.8 ± 22.6 s) (mean ± SD), nor for any of the other variables measured (P>0.05) apart from a significant condition effect with FA and significant interaction effects observed for glucose, β-hydroxybutyrate and lactate (P<0.05). These findings suggest that the type of CHO ingested in a pre-match meal has no significant impact on performance or metabolic responses during 90 min of intermittent high intensity exercise.

Effectiveness of a community football programme on improving physiological markers of health in a hard-to-reach male population: the role of exercise intensity

The present study evaluated the effectiveness of participation in recreational football during a community health programme, on physiological markers of health within a hard to reach population. Nine men (Age: 33 ± 9 years, Mass: 75.4 ± 13.7 kg, Height: 1.74 ± 0.07 m and Body Fat: 19 ± 2%) were recruited to participate in the study in collaboration with an English Premier League Football Club. Participants completed the 12-week football-based programme which included two coached football sessions each week. Physiological tests for blood pressure, resting heart rate, cholesterol and an anthropometrical test for body composition were completed at three time points during the study (Weeks – 1, 6 and 12) in an attempt to evaluate the impact of the intervention on health. During each training session, measurements of intensity (%HRmax, identified from the yoyo intermittent level 1 test), duration and rating of perceived exertion were made. The 12-week programme (mean HRmax throughout programme = 75 ± 4% beats min−1; mean RPE throughout programme = 6 ± 1) elicited few changes in physiological markers of health with the only significant change been a decrease in resting heart rate from weeks 6 to 12 (87 ± 22 beats min−1 at week-6, to 72 ± 17 beats min−1; p < 0.05). These data would suggest that the current community football-related health project was not effective in improving physiological markers of health, but was able to maintain their level of health. A lack of improvement may be due to the low intensity of sessions and a lack of coach education for the promotion of sessions that aim to improve health.

Effect of Fat and CHO Meals on Intermittent Exercise in Soccer Players

Pre-exercise meals containing carbohydrates (CHO) are recommended to athletes, although there is evidence to suggest that a high fat meal prior to exercise increases utilisation of fats yet may not adversely affect performance. This study investigated the effect of a high fat and high CHO pre-exercise meal prior to high intensity intermittent exercise. Ten male recreational soccer players performed a soccer specific protocol followed by a 1 km time trial 3 ½ h after ingesting one of 2 test meals, high fat meal (HFM) or a high CHO meal (HCM). Blood glucose, fatty acids (FA), glycerol, β-hydroxybutyrate, lactate and insulin were assessed prior to the meal, pre-exercise, half-time, and post-exercise, whilst rates of CHO and fat oxidation were determined at 4 time points during the exercise as well as heart rate (HR) and rating of perceived exertion (RPE). Significant increases in FA, glycerol, β-hydroxybutyrate and fat oxidation after the HFM were observed, while CHO oxidation was significantly higher following the HCM (P<0.05). No performance effect was found for the 1 km time trial (HFM: 228.6+14.4 s; HCM: 229.4+26.5 s) (mean+SD). These findings suggest that the type of meal ingested prior to soccer simulated exercise has an impact on metabolism, but not on the subsequent performance as determined in the present study.

Evaluation of the external and internal workload in female futsal players

Match analysis technology has been extensively used in football, but there is limited literature on its use in futsal. Despite its increased popularity, the female futsal game model has never been quantified. The aim of this study was to quantify locomotor and mechanical activities performed during a non-competitive female futsal match, measuring the differences between the first and second half. Sixteen female futsal players of the Italian 2nd division were enrolled (age 27±5 years, height 1.65±0.09 m, body weight 56.9±7.7 kg, BMI 20.9±1.9, fat mass 21.5±2.9%). Locomotor and mechanical activities were recorded by means of the 10 Hz GPS StatSports system. Games were performed on a 38x18 m synthetic grass outdoor pitch. Significant differences were found between the first and second half in total distance (1424±114 and 1313±113 m, p<0.05), relative velocity (70±6 and 64±6 m min-1, p<0.05), high speed running (28±16 and 22±19 m, p<0.05) and high metabolic distance (80 ± 29 and 69 ± 28 m, p<0.05). The match analysis of female futsal matches provides useful information about its external load demands. Female futsal players decreased the workload in the second half compared to the first one during this non-competitive match. It was found that fatigue impairs the performance in the second part of the game. Coaches and physical trainers can obtain useful information to design training programmes taking into account the quantification of locomotor and mechanical activities performed in this study.

Erratum to: Applied Physiology of Female Soccer: An Update

Page 2, section 2, paragraph 2, column 2, lines 4–6: The following sentence, which previously read: ‘‘However, since this time, national team players have been reported to cover a distance of 1.53–1.68 km at high speeds ([18 km h) [10, 12, 14].’’ should read: ‘‘However, since this time, national team players have been reported to cover a distance of 1.53–1.68 km at high speeds ([15 km h) [10, 12, 14].’’