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The physical demands of English Premier League soccer goalkeepers were quantified during training and match-play in a two-part study. Goalkeeper-specific micromechanical electrical systems (MEMS) devices, profiled training and match-day activities throughout one competitive week (n=8; part A). Changes in MEMS-derived outputs were also profiled throughout match-play (100 matches; n=8, 18±14 observations per goalkeeper; part B). In part A, goalkeeping-training elicited the most dives (51±11) versus all activities (all p≤0.030) except shooting-training (p=0.069). Small-sided games elicited the fewest (5±3) dives (all p≤0.012). High-speed distance covered in match (103±72 m) was similar to goalkeeping-training (p=0.484), while exceeding shooting-training, small-sided games, pre-match shooting, and pre-match warm-up (all p=0.012). Most changes of direction (34±12) and explosive efforts (70±18) occurred during goalkeeping-training, with values exceeding match (both p=0.012). In part B, between-half reductions in total distance, but increased high-speed changes of direction and explosive efforts, occurred (both p≤0.05). Excluding the number of high jumps, all variables differed from 0-15-min during at least one match epoch, with more dives (1.3±1.4 vs 1.0±1.1) and explosive efforts (2.5±2.4 vs 2.0±1.8) performed between 75-90-min versus 0-15-min (all p<0.05). These data highlight the differing physical demands of various activities performed by professional soccer goalkeepers throughout a competitive week. [ABSTRACT FROM AUTHOR]

The purpose of the study was to assess the validity and inter-bike reliability of 10 Wattbike cycle ergometers, and to assess the test–retest reliability of one Wattbike. Power outputs from 100 to 1000 W were applied using a motorised calibration rig (LODE) at cadences of 70, 90, 110 and 130 rev · min−1, which created nineteen different intensities for comparison. Significant relationships (P < 0.01,r2 = 0.99) were found between each of the Wattbikes and the LODE. Each Wattbike was found to be valid and reliable and had good inter-bike agreement. Within-bike mean differences ranged from 0.0 W to 8.1 W at 300 W and 3.3 W to 19.3 W at 600 W. When taking into account the manufacturers stated measurement error for the LODE (2%), the mean differences were less than 2%. Comparisons between Wattbikes at each of the nineteen intensities gave differences from 0.6 to 25.5 W at intensities of 152 W and 983 W, respectively. There was no significant difference (P > 0.05) between the measures of power recorded in the test–retest condition. The data suggest that the Wattbike is an accurate and reliable tool for training and performance assessments, with data between Wattbikes being able to be used interchangeably. [ABSTRACT FROM AUTHOR]

Growth and maturation impact the selection, development and progression of youth athletes. Individual differences in the growth and maturity may afford a performance advantage, clouding coaches and practitioners' perceptions regarding current ability and future potential. This may result in the exclusion of talented, yet less physically gifted athletes. Participants were 91 male (n = 47) and female (n = 44) elite British Junior tennis players, 8-17 years of age (12.5 ± 1.9 years). Height and body mass were measured and compared to growth charts; hand-wrist radiographs were taken. Skeletal age (SA) was estimated with the Fels method and contrasted to chronological age (CA). Mean height and body mass of individual players ranged between the 50th and 90th centiles for age and sex. Females were advanced in SA relative to CA (0.3-0.89 years.) from 8 years. Males were average to delayed in maturation from 8 to 12 years, but advanced in SA from 14 to 16 years (0.75-1.23 years). Individual differences in growth and maturation appear to contribute towards the selection of elite junior tennis players, with a bias towards males and females who are advanced in maturation and comparatively tall and heavy for their age. This has important implications for talent identification and development. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of annual-age category, relative age, playing position, anthropometry and fitness on the career attainment outcomes of junior rugby league players originally selected for a talent identification and development (TID) programme. Junior rugby league players (N = 580) were grouped retrospectively according to their career attainment level (i.e., amateur, academy and professional). Anthropometric (height, sitting height, body mass, sum of four skinfolds), maturational (age at peak height velocity; PHV) and fitness (power, speed, change of direction speed, estimated) characteristics were assessed at the Under 13s, 14s and 15s annual-age categories. Relative age (Q2 = 8.5% vs. Q4 = 25.5%) and playing position (Pivots = 19.5% vs. Props = 5.8%) influenced the percentage of players attaining professional status. Anthropometry and fitness had a significant effect on career attainment at the Under 14 (P = 0.002,η2 = 0.16) and 15 (P = 0.01,η2 = 0.12) annual-age categories. Findings at the Under 14s showed future professional players were significantly later maturing compared to academy and amateur players. Findings suggest that relative age, playing position, anthropometry and fitness can influence the career attainment of junior rugby league players. TID programmes within rugby league, and other related team sports, should be aware and acknowledge the factors influencing long-term career attainment, and not delimit development opportunities during early adolescence. [ABSTRACT FROM PUBLISHER]

The purpose of the current study was to develop an instrument, the Children’s Active Play Imagery Questionnaire (CAPIQ), to assess imagery use during children’s (7–14 years) active play. Phase 1 involved an assessment of content validity using experts (N = 7), while Phase 2 assessed the factorial validity of the CAPIQ using a sample of children (N = 302). Phase 3 contributed to the factorial validity of the CAPIQ by utilising confirmatory factor analysis among an independent sample of children (N = 252). The final version of the CAPIQ consists of 11 items across three factors: fun, social and capability. Further use of the CAPIQ will aid in identifying types of imagery used among children (7–14 years) in their active play, which may contribute to physical activity interventions. [ABSTRACT FROM AUTHOR]

Velocity coupling denotes a perceptual motor behaviour known to occur during coincidence timing tasks. Individuals have been shown to increase their effector limb speed with increases in stimulus speed during interceptive tasks. However, little is known about the physiological effects of velocity coupling. The aim of this study was to determine the physiological cost of velocity coupling during tennis groundstrokes. Eight male and eight female competitive tennis players volunteered to perform three 4-min bouts of continuous groundstrokes against balls projected from a tennis ball machine at speeds of 18, 22, and 27 m · s-1 (65, 79, and 97 km · h-1) and a frequency of 14 balls per minute, the order of which was counterbalanced. Breath-by-breath pulmonary gas exchange, heart rate, locomotion time, and limb acceleration were measured throughout each of the 4-min bouts. Capillary blood samples (for blood lactate analysis), rating of perceived exertion, and difficulty rating were taken at the end of each bout. Increasing ball speed did not influence the locomotion time between groundstrokes but did result in a bilateral increase in both the mean upper- and lower-limb acceleration (all P < 0.05). Velocity coupling behaviour increased oxygen uptake, blood lactate concentration, heart rate, rating of perceived exertion, and perceived task difficulty (all P < 0.05). It would appear, therefore, that velocity coupling influenced tennis groundstroke behaviour and indirectly modified the concurrent cardiopulmonary and metabolic responses. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the influence of a pressurized tennis ball 6% greater in diameter (Type 3) than a standard sized (Type 2) ball on performance and the physiological responses to the Loughborough Intermittent Tennis Test (LITT) ( Davey et al ., 2002 ). Eight competitive tennis players (males, n = 4, age 24.8 ± 3.5 years, body mass 81.3 ± 3.1 kg, height 1.74 ± 0.02 m, estimated &Vdoti;O 2max 54.4 ± 2.6 ml · kg -1 · min -1 ; females, n = 4, age 26.3 ± 3.1 years, body mass 67.0 ± 6.7 kg, height 1.68 ± 0.02 m, estimated &Vdoti;O 2max 49.9 ± 3.3 ml · kg -1 · min -1 ; mean ± ) completed two main trials of the LITT with either the Type 2 or Type 3 tennis balls to the point of volitional fatigue. The mean time to volitional fatigue was 29.5% greater during the Type 3 trials than during the Type 2 trials (56.9 ± 6.4 min vs 40.1 ± 3.7 min; P < 0.05). The mean percentage accuracy and mean percentage consistency recorded for the entire LITT were greater for the Type 3 than the Type 2 trials (9.2 ± 1.5 vs 4.0 ± 0.3% and 61.1 ± 0.6 vs 51.3 ± 0.6%, respectively; P < 0.01). A significantly lower mean heart rate and blood lactate concentration were observed during the Type 3 than during the Type 2 trials. There was a clear effect of ball diameter on tennis performance and certain physiological responses. [ABSTRACT FROM AUTHOR]

The aim of this study was to identify the kinematic and postural characteristics associated with sprint running on uphill and downhill slopes of 3° and on a horizontal surface. Eight male physical education students were filmed while sprinting maximally on an uphill-downhill platform under each of three conditions: (a) uphill at 3°, (b) downhill at 3° and (c) horizontal. Running speed, step rate, step length, step time, contact time, flight time and selected postural characteristics of the step cycle were analysed. Running speed was 9.2% faster (P < 0.05) during downhill and 3.0% slower (P < 0.05) during uphill compared with horizontal sprint running. During downhill and uphill sprint running, step length was the main contributor to the observed changes in running speed. It increased by 7.1% (P < 0.05) for downhill sprint running and was associated with significant changes in posture at touchdown and take-off. During uphill sprint running, step length decreased by 5.2% (P < 0.05), which was associated with significant changes in posture and reduced flight distance. Given the interaction between the acute changes in step length and posture when sprinting on a sloping surface, our findings suggest that such changes in posture may detract from the specificity of training on such surfaces. The chronic effects of training on such slopes on the kinematics and posture of horizontal sprint running are currently unclear. [ABSTRACT FROM AUTHOR]

Presents abstracts on sport sciences presented at the Annual Conference of the British Association of Sport and Exercise Sciences in Great Britain. 'Mechanical Power in Submaximal Speed Sprinting.'

We investigated the effect of an acute creatine loading (25 g per day for 4 days) and longer-term creatine supplementation (5 g of creatine or 5 g of placebo per day for 2 months) on the performance of 22 elite swimmers during maximal interval sessions. After the acute creatine loading, the mean of the average interval swim times for all swimmers (n = 22) improved (44.3 +/- 16.5 s before vs 43.7 +/- 16.3 s after supplementation; P < 0.01). Three of the 22 swimmers did not respond positively to supplementation. After 2 months of longer term creatine supplementation or placebo,neither group showed a significant change in swimming performance (38.7 +/-13.5 s before vs 38.7 +/- 14.1 s after for the creatine group; 48.7 +/- 18.0 s before vs 48.7 +/- 18.1 s after for the placebo group). We conclude that, in elite swimmers, 4 days of acute creatine loading improves swimming performance significantly when assessed by maximal interval sessions. However, longer-term supplementation for 2 months (5 g of creatine per day) did not benefit significantly the creatine group compared with the placebo group. [ABSTRACT FROM AUTHOR]

Presents books on sports sciences. `Managing Health Promotion Programmes,' by B. Wilson and T. Glaros; `Functional Progressions for Sport Rehabilitation,' by S.R. Tippert and M.L Voight; `Complete Guide to Youth Fitness Testing,' by M.J. Safrit; 'Child Health, Nutrition and Physical Activity' edited by L.W.Y. Cheung and J.B. Richmond; `Fundamentals of Orthopaedic Biomechanics,' by A.H. Burstein and T.M. Wright; `Biomechanical Basis of Human Movement,' J. Hamill and K.M. Knutzen.

The potential for imprecision in the estimation of hydration status from changes in body mass has been outlined previously but the equations derived from these derivations appear inconsistent. Reconciliation of body mass loss in terms of sweat loss and effective body water loss is possible from specific equation sets provided that gains and losses of both body mass and water used in the derivation of sweat loss and to derive effective body water loss are in inclusive equation sets. This is obligatory so that mass and water changes as quantifiable determinants are consistent with both internal processes and external gains and losses. Thus, body mass loss, substrate oxidation, metabolic water, and all the terms used in simultaneous equation sets have to be reconciled not only as identical variables but mathematically balance exactly. The revised equation for effective body water loss given here is different from that originally proposed. Metabolic water is part of body mass loss corrected for substrate oxidation, fluid ingestion, and respiratory water to derive sweat loss and it may not be justified to also include water associated with glycogen as releasable bound water. Accordingly, our calculated effective body water loss is substantially a greater loss than originally supposed but clearly still less than the simple balance between mass loss and fluid ingested. [ABSTRACT FROM AUTHOR]

Editorial. Comments on the 1999 Annual Conference of the British Association of Sport and Exercise Sciences in Great Britain. Issues presented in the conference; Inclusion of agenda-setting lectures by association and organization representatives; Trade exhibitions in the conference program.