This study examined the contribution of phosphocreatine (PCr) and aerobic metabolism during repeated bouts sprint exercise. Eight male subjects performed two cycle ergometer sprints separated by 4 min recovery separate main trials. Sprint 1 lasted 30 s both trials, whereas 2 either 10 or s. Muscle biopsies were obtained at rest, immediately after first 30-s sprint, 3.8 recovery, second 10- sprints. At end 1, PCr was 16.9 +/- 1.4% resting value, muscle pH dropped to 6.69 0.02. After remained...

1. The recovery of power output and muscle metabolites was examined following maximal sprint cycling exercise. Fourteen male subjects performed two 30 s cycle ergometer sprints separated by 1.5, 3 6 min recovery, on three separate occasions. On a fourth occasion eight the only one biopsies were obtained during recovery. 2. At end phosphocreatine (PCr) ATP contents 19.7 +/‐ 1.2 70.5 6.5% resting values (rest), respectively, while lactate 119.0 4.6 mmol (kg dry wt)‐1 pH 6.72 0.06. During PCr...

On two separate days eight male subjects performed a 10‐ or 20‐s cycle ergometer sprint (randomized order) followed, after 2 min of recovery, by 30‐s sprint. Muscle biopsies were obtained from the vastus lateralis at rest, immediately first and recovery on both occasions.The anaerobic ATP turnover during initial 10 s 1 was 129 ± 12 mmol kg dry weight −1 decreased to 63 between 10th 20th 1. This result 300% decrease in rate phosphocreatine breakdown 35% glycolytic rate. Despite this 51%...

Sixteen subjects volunteered for the study and were divided into a control (4 males 4 females) experimental group females, who undertook 8 wk of sprint training). All completed maximal 30-s on nonmotorized treadmill 2-min run motorized at speed designed to elicit 110% maximum oxygen uptake (110% run) before after period training. Muscle biopsies taken from vastus lateralis rest immediately exercise. The metabolic responses unchanged over 8-wk period. However, training resulted in 12% (P less...

1. Muscle biopsy samples were obtained from the vastus lateralis of six healthy volunteers before and after 30 s treadmill sprinting. A portion each sample was used for mixed‐fibre metabolite analysis. Single fibres dissected remaining ATP, phosphocreatine (PCr) glycogen determination. 2. Before exercise, PCr contents higher in type II (79.3 +/‐ 2.7 472 35 mmol (kg dry matter (DM)‐1, respectively) compared with I (71.3 3.0 DM)‐1, P < 0.01 375 25 0.001, respectively). 3. Peak power output...

Muscle strength is thought to be a major factor in athletic success. However, the relationship between muscle and sprint performance has received little attention. The aim of this study was examine elite performers isokinetic across three lower limb joints sprinting performance, including use theoretical models. Eight rugby players, eight track sprinters competitive sportsmen, all national or regional competitors, performed sprints over 15 m 35 with times recorded 0-15 30-35 m. Isokinetic...

Physical inactivity is recognised as a public health concern within children and interventions to increase physical activity are needed. The purpose of this research was evaluate the effect school-based healthy lifestyles intervention on activity, fruit vegetable consumption, body composition, knowledge, psychological variables. A non-randomised controlled study involving 8 primary schools (4 intervention, 4 control). Participants were 589 aged 7–11 years. lasted 10 months comprised CD-rom...

It is well documented that heat acclimation of six or more sessions at least 60 min duration prolongs the time to exhaustion during endurance walking, cycling and running in heat. However, this type not specific team sport activity effect on prolonged high-intensity intermittent has yet been investigated.To assess impact an protocol distance run activity.The four short (30-45 Loughborough Intermittent Shuttle Test; LIST) capacity (LIST) (30 degrees C, 27% relative humidity (RH)), was...

It has been suggested that a low-glycaemic index (GI) breakfast may be beneficial for some elements of cognitive function (e.g. memory and attention), but the effects are not clear, especially in adolescents. Thus, aim present study was to examine low-GI breakfast, high-GI omission on A total fifty-two adolescents aged 12–14 years were recruited participate study. Participants consumed or omitted breakfast. battery tests completed 30 120 min following consumption capillary blood samples...

Moderate intensity exercise has been shown to enhance cognition in an adolescent population, yet the effect of high-intensity sprint-based remains unknown and was therefore examined present study. Following ethical approval familiarisation, 44 adolescents (12.6 ± 0.6 y) completed (E) resting (R) trial a counter-balanced, randomised crossover design. The comprised 10 × s running sprints, interspersed by 50 active recovery (walking). A battery cognitive function tests (Stroop, Digit Symbol...

An acute bout of exercise elicits a beneficial effect on subsequent cognitive function in adolescents. The games-based activity, an ecologically valid and attractive model for young people, remains unknown; as does the moderating fitness exercise-cognition relationship. Therefore, aim present study was to examine activity cognition adolescents, this relationship.Following ethical approval, 39 adolescents (12.3 ± 0.7 year) completed resting trial counterbalanced, randomised crossover design....

Abstract Six games players (GP) and six endurance‐trained runners (ET) completed a standardized multiple sprint test on non‐motorized treadmill consisting often 6‐s all‐out sprints with 30‐s recovery periods. Running speed, power output oxygen uptake were determined during the blood samples taken for determination of lactate pH. Games tended to produce higher peak (GP vs ET: 839 ± 114 777 89 W, N.S.) speed 7.03 0.3 6.71 m s‐1, N.S.), but had greater decrement in mean than 29.3 8.1% 14.2...

This study examined (1) the distances and speeds covered during match play for U11 to U16 English Premier League Academy players, (2) differences in performance between retained released players (3) effect of calculating speed zones different ways when analysing performance. Eighty-one academy outfield (10-16 years old), competing 11-a-side matches, were analysed using a 1-Hz global positioning system with three (absolute, squad individual). Pitch dimensions 78.7 × 54.1 m (U11 U12), 88.0...

Abstract We studied the effects of oral creatine supplementation on sprint swimming performance in 14 elite competitive male swimmers. The subjects performed a single (1 X 50 yards [45.72 m]) and repeated set (8 at intervals 1 min 30 s) before after 5 day period either (9g + 4.5g maltodextrin glucose day-1) or placebo (18g day-1; double-blind protocol) supplementation. Venous capillary blood samples were taken for determination plasma ammonia, pH lactate. Mean times recorded yard unchanged...

Abstract Seven healthy male subjects performed 10 maximal 6‐s sprints, separated by 30‐s recovery periods, on a non‐motorized treadmill. On two occasions, 3 days, the ingested solution of either sodium bicarbonate (NaHCO3; alkaline) or chloride (NaCl; placebo), 2.5 h prior to exercise. The doses were 0.3 g kg‐1 body mass for alkaline treatment and 1.5 total placebo, dissolved in 500 ml water. order testing was randomly assigned. Pre‐exercise blood pH 7.43 ± 0.02 7.38 0.01 placebo trials...

To investigate the influence of ingesting versus mouth rinsing a carbohydrate-electrolyte solution on 1-h running performance.After 14- to 15-h fast, 10 endurance-trained male runners (mean ± SD: VO2peak = 65.0 4.4 mL·kg(-1)·min(-1)) completed three performance runs separated by 1 wk. In random order, ingested either 8-mL·kg(-1) body mass 6.4% (CHO) or placebo (P) 30 min before 2-mL·kg(-1) at 15-min intervals throughout run. On separate occasion, rinsed (R) CHO, i.e., without ingestion, same...

The validity and reliability of a battery field-based performance tests was examined. opinions coaches, fitness professionals players (n=170, 172 101 respectively) on the importance testing were established using questionnaire. On 2 occasions, separated by 7 days, 80 elite, young soccer (mean±SD [and range]: age 13.2±2.6 [8.9–19.1] years; stature 1.59±0.18 m [1.32–1.91]; body mass 50.6±17.1 [26.5–88.7] kg) completed comprised heart rate response to submaximal Multi-stage test, 3 types...

This study longitudinally examined age-related changes in the match-running performance of retained and released elite youth soccer players aged 8-18 years. The effect playing position on was also considered. Across three seasons, 263 were assessed 1-29 competitive matches (988 player-matches). For each player-match, total distance distances covered at age group-specific speed zones (low-speed, high-speed, sprinting) calculated using 1 Hz or 5 GPS. Mixed modeling predicted that developed...