Andrew Foskett

Validation of a soccer skill test for use with females.

The aim of this study was to validate the Loughborough Soccer Passing Test (LSPT) for use with female players. Nineteen Premier Division (elite) and 16 Reserve team players (nonelite) volunteered for this study. The LSPT requires players to complete 16 passes against coloured target areas as fast and as accurately as possible. Participants completed an initial familiarisation trial followed by two main trials, each separated by at least one week. During both trials participants were given two practice efforts before recording the mean of the next two attempts as the performance score. All trials were performed inside a sports hall, using an indoor soccer ball, and following a standardised 10-min warm-up. The mean time taken (54.6 +/- 5.3 s vs. 61.6 +/- 6.5 s, p = 0.002), added penalty time (22.8 +/- 7.2 s vs. 35.9 +/- 11.5 s, p < 0.001) and overall performance time (77.4 +/- 11.6 s vs. 97.5 +/- 17.2 s, p < 0.001) were lower for elite players. Due to the lower agreement ratio, LSPT performance was more repeatable in the elite (x//1.39) relative to nonelite (x//1.45) group. In conclusion, the LSPT is a valid and reliable protocol to assess differences in soccer skill performance using female players.

Fluid balance, thermoregulation and sprint and passing skill performance in female soccer players

Ten females performed 90 min of the Loughborough Intermittent Shuttle Test (LIST) on two occasions separated by 7 days. Water [3 mL/kg body mass (BM)] was provided every 15 min during exercise (FL); no fluid was given in the other trial (NF). Participants performed the Loughborough Soccer Passing Test (LSPT) before and every 15 min during the LIST. Core temperature (Tc) was measured throughout using ingestible temperature sensors. Heart rate (HR), blood lactate ([La−]) and ratings of perceived exertion (RPE) were collected at regular intervals during exercise. Participants experienced greater BM loss in NF (2.2 ± 0.4%) than FL (1.0 ± 0.4%; P<0.001). Sprint performance deteriorated by 2.7% during exercise (P<0.001) but there was no difference between trials (P=0.294). No significant differences in LSPT performance were detected between trials (P=0.31). Tc was higher during exercise in NF and was 38.6 ± 0.3 °C (NF) and 38.3 ± 0.3 °C (FL; P<0.01) after 90 min. HR (P<0.001), [La−] (P<0.01) and RPE (P=0.009) were higher during exercise in NF. Ingesting water during a 90‐min match simulation reduces the mild dehydration seen in female soccer players when no fluid is consumed. However, there was no effect of fluid ingestion on soccer passing skill or sprint performance.

Rapid directional change degrades GPS distance measurement validity during intermittent intensity running.

Use of the Global Positioning System (GPS) for quantifying athletic performance is common in many team sports. The effect of running velocity on measurement validity is well established, but the influence of rapid directional change is not well understood in team sport applications. This effect was systematically evaluated using multidirectional and curvilinear adaptations of a validated soccer simulation protocol that maintained identical velocity profiles. Team sport athletes completed 90 min trials of the Loughborough Intermittent Shuttle-running Test movement pattern on curvilinear, and multidirectional shuttle running tracks while wearing a 5 Hz (with interpolated 15 Hz output) GPS device. Reference total distance (13 200 m) was systematically over- and underestimated during curvilinear (2.61±0.80%) and shuttle (−3.17±2.46%) trials, respectively. Within-epoch measurement uncertainty dispersion was widest during the shuttle trial, particularly during the jog and run phases. Relative measurement reliability was excellent during both trials (Curvilinear r = 1.00, slope = 1.03, ICC = 1.00; Shuttle r = 0.99, slope = 0.97, ICC = 0.99). Absolute measurement reliability was superior during the curvilinear trial (Curvilinear SEM = 0 m, CV = 2.16%, LOA ± 223 m; Shuttle SEM = 119 m, CV = 2.44%, LOA ± 453 m). Rapid directional change degrades the accuracy and absolute reliability of GPS distance measurement, and caution is recommended when using GPS to quantify rapid multidirectional movement patterns.

Dietary Intake, Anthropometric Characteristics, and Iron and Vitamin D Status of Female Adolescent Ballet Dancers Living in New Zealand

Ballet dancing is a multifaceted activity requiring muscular power, strength, endurance, flexibility, and agility; necessitating demanding training schedules. Furthermore dancers may be under aesthetic pressure to maintain a lean physique, and adolescent dancers require extra nutrients for growth and development. This cross-sectional study investigated the nutritional status of 47 female adolescent ballet dancers (13-18 years) living in Auckland, New Zealand. Participants who danced at least 1 hr per day 5 days per week completed a 4-day estimated food record, anthropometric measurements (Dual-energy X-ray Absorptiometry) and hematological analysis (iron and vitamin D). Mean BMI was 19.7 ± 2.4 kg/m2 and percentage body fat, 23.5 ± 4.1%. The majority (89.4%) of dancers had a healthy weight (5th-85th percentile) using BMI-for-age growth charts. Food records showed a mean energy intake of 8097.3 ± 2155.6 kJ/day (48.9% carbohydrate, 16.9% protein, 33.8% fat, 14.0% saturated fat). Mean carbohydrate and protein intakes were 4.8 ± 1.4 and 1.6 ± 0.5 g/kg/day respectively. Over half (54.8%) of dancers consumed less than 5 g carbohydrate/kg/day, and 10 (23.8%) less than 1.2 g protein/kg/day. Over 60% consumed less than the estimated average requirement for calcium, folate, magnesium and selenium. Thirteen (28.3%) dancers had suboptimal iron status (serum ferritin (SF) < 20 μg/L). Of these, four had iron deficiency (SF < 12 μg/L, hemoglobin (Hb) ≥ 120 g/L) and one iron deficiency anemia (SF < 12 μg/L, Hb < 120 g/L). Mean serum 25-hydroxy vitamin D was 75.1 ± 18.6 nmol/L, 41 (91.1%) had concentrations above 50 nmol/L. Female adolescent ballet dancers are at risk for iron deficiency, and possibly inadequate nutrient intakes.

Measuring intermittent exercise performance using shuttle running

Abstract The aim of this study was to include self-paced exercise within a modified Loughborough Intermittent Shuttle Test (LIST-P) in order to quantify key performance variables not possible with prescribed workloads. Sixteen male games players performed two trials of the LIST-P, at least 7 days apart. The LIST-P incorporates 4 × 15-min blocks of “prescribed-pace” activity (participants exercise in time to audible signals) followed by 2 × 15-min blocks of “self-paced” running (no audible signals). Distances covered and mean speeds were monitored during self-paced exercise. Total distance covered (12.54 ± 0.45 km vs. 12.64 ± 0.32 km; P = 0.10) and mean speed (8.37 ± 0.31 km ∙ h−1 vs. 8.44 ± 0.22 km ∙ h−1; P = 0.10) was similar between trials. Other indices also showed the test to be reliable (Pearson’s correlation = 0.89 and 0.90 (P < 0.01), total distance and mean speed, respectively; intraclass correlation coefficient = 0.88 and 0.88 (P < 0.01); standard error of measurement = ±0.13 km and ±0.09 km ∙ h−1; coefficient of variation (CV) = 1.7% and 1.7%; ratio limits of agreement = 1.00 */÷1.03 and 1.01 */÷1.04). Sprint time was also similar between trials (2.60 ± 0.19 s vs. 2.64 ± 0.23 s; P = 0.29). Incorporating self-paced exercise within an established intermittent shuttle running test appears to be a sensitive means of quantifying key performance variables for multiple-sprint sports research.

Caffeine ingestion enhances perceptual responses during intermittent exercise in female team-game players

Abstract We examined the influence of caffeine supplementation on cognitive performance and perceptual responses in female team-game players taking low-dose monophasic oral contraceptives of the same hormonal composition. Ten females (24 ± 4 years; 59.7 ± 3.5 kg body mass; 2–6 training sessions per week) took part in a randomised, double-blind, placebo-controlled crossover-design trial. A 90-min intermittent treadmill-running protocol was completed 60 min following ingestion of a capsule containing either 6 mg • kg−1 anhydrous caffeine or artificial sweetener (placebo). Perceptual responses (ratings of perceived exertion (RPE), feeling scale (FS), felt arousal scale (FAS)), mood (profile of mood states (POMS)) and cognitive performance (Stroop test, choice reaction time (CRT)) were completed before, during and after the exercise protocol, as well as after ~12 h post exercise. Caffeine ingestion significantly enhanced the ratings of pleasure (P = 0.008) and arousal (P = 0.002) during the exercise protocol, as well as increased vigour (POMS; P = 0.007), while there was a tendency for reduced fatigue (POMS; P = 0.068). Caffeine ingestion showed a tendency to decrease RPE (P = 0.068) and improve reaction times in the Stroop (P = 0.072) and CRT (P = 0.087) tests. Caffeine supplementation showed a positive effect on perceptual parameters by increasing vigour and a tendency to decrease fatigue during intermittent running activity in female games players taking low-dose monophasic oral contraceptive steroids (OCS).

Motion Analysis of Match Play in New Zealand U13 to U15 Age-Group Soccer Players

Abstract Atan, SA, Foskett, A, and Ali, A. Motion analysis of match play in New Zealand U13 to U15 age-group soccer players. J Strength Cond Res 30(9): 2416–2423, 2016—The purpose of this study was to investigate motion analysis in 85 players (U13–U15 years) from Aucklands Metropolitan League during 2 competitive soccer matches. Five-Hz global positioning system (with interpolated 10-Hz output) units were used to measure total distance (absolute and relative) and time spent in standing, walking, low-intensity running, medium-intensity running, high-intensity running, and sprinting. Speed thresholds for each match activity were determined through mean 10-m flying sprint peak speed for each age group. Under 15 years (U15, 6600 ± 1480 m) covered more absolute distance because of longer playing time than under 14 years (U14, 5385 ± 1296 m, p = 0.001) and under 13 years (U13, 4516 ± 702.6 m, p = 0.001). However, there were no differences in relative distances covered (U15, 94.5 ± 11.2 m·min−1, U14, 96.1 ± 11.9 m·min−1, U15, 97.3 ± 17.6 m·min−1, p = 0.685). Maximum speed attained during the match was faster for U15 (26.5 ± 1.68 km·h−1) than U14 (25.4 ± 1.93 km·h−1, p = 0.022) and U13 (23.5 ± 1.74 km·h−1, p = 0.001); there were no differences in average distance per sprint, with all age groups covering ∼16 m per sprint (p = 0.603). The current findings provide useful information for developing specific training programs for young soccer players and a framework for developing age-specific soccer simulation protocols.

Effect of Alcohol Consumption on Recovery From Eccentric Exercise Induced Muscle Damage in Females

This study was designed to investigate the effects of alcohol consumption on recovery of muscle force when consumed immediately postexercise in young females. Eight young women completed 300 maximal eccentric actions of the quadriceps femoris muscle on an isokinetic dynamometer on two occasions in a randomized, cross-over design after which an alcoholic beverage (0.88g ethanol/kg body weight) or an iso-caloric placebo was consumed. Maximal isokinetic (concentric and eccentric) torque and isometric tension produced across the knee were measured in both the exercised and control leg predamage, 36 hr post, and 60 hr post damage. Venous blood creatine kinase (CK) activity and muscle soreness ratings were taken before damage and once per day to 60 hr post damage. Significant differences were observed between the exercised and control leg for maximal concentric, and eccentric torque and isometric tension (p < .05). A near significant Treatment × Time interaction was observed for isometric tension (p = .077), but not for concentric or eccentric torque. No main effects of treatment (alcohol) or interactions with Time × Leg or Leg × Treatment were observed. Perceived muscle soreness during box stepping and squatting showed significant time effects (p < .05), and CK activity did not significantly change. Our results indicate that the consumption of 0.88g ethanol/kg body weight following eccentric exercise-induced muscle damage does not affect recovery in the days following damage in females.

Potentiation of sprint cycling performance: the effects of a high-inertia ergometer warm-up

ABSTRACT Participant and protocol factors affect post-activation potentiation response. Performance enhancement is more consistent in highly-trained participants following multiple sets of a biomechanically similar conditioning activity. Providing optimal conditions, 6 international-level sprint cyclists executed multiple sets of short maximal conditioning contractions on a high-inertia ergometer before metered sprint performance. Three trial conditions were completed on separate days after a standardised warm-up: dynamic (DYN: 4 × 4 crank-cycles), isometric (ISO: 4 × 5-sec maximal voluntary contraction (MVC)), and control (CON: rest). Performance was measured from standing start to maximum velocity on an inertial-load ergometer at baseline (Pre), 4 (Post4), 8 (Post8) and 16 (Post16) min post-conditioning. Performance and biomechanical measures were assessed across 4 sprint segments, with magnitude-based inferences used to assess the likelihood that any affect was beneficial. Performance time only improved in DYN Post4, a 3.9% reduction during the first crank cycle (92% likely). On the ascending limb of the power-cadence relationship, peak torque and average power increased by 6.2% (94% likely) and 4.0% (87% likely), respectively. In ISOPost16, optimal cadence increased (82% likely) and average power improved over the descending limb (76% likely). DYN and ISO potentiated extremities of the torque-cadence relationship at distinct recovery times post-conditioning. This study suggests merit in including a high-inertia warm-up for sprint cycling.