This study aimed to investigate the validity and reliability of global (GPS) and local (LPS) positioning systems for measuring distances covered and sprint mechanical properties in team sports. Here, we evaluated two recently released 18 Hz GPS and 20 Hz LPS technologies together with one established 10 Hz GPS technology. Six male athletes (age: 27±2 years; VO2max: 48.8±4.7 ml/min/kg) performed outdoors on 10 trials of a team sport-specific circuit that was equipped with double-light timing gates. The circuit included various walking, jogging, and sprinting sections that were performed either in straight-lines or with changes of direction. During the circuit, athletes wore two devices of each positioning system. From the reported and filtered velocity data, the distances covered and sprint mechanical properties (i.e., the theoretical maximal horizontal velocity, force, and power output) were computed. The sprint mechanical properties were modeled via an inverse dynamic approach applied to the center of mass. The validity was determined by comparing the measured and criterion data via the typical error of estimate (TEE), whereas the reliability was examined by comparing the two devices of each technology (i.e., the between-device reliability) via the coefficient of variation (CV). Outliers due to measurement errors were statistically identified and excluded from validity and reliability analyses. The 18 Hz GPS showed better validity and reliability for determining the distances covered (TEE: 1.6–8.0%; CV: 1.1–5.1%) and sprint mechanical properties (TEE: 4.5–14.3%; CV: 3.1–7.5%) than the 10 Hz GPS (TEE: 3.0–12.9%; CV: 2.5–13.0% and TEE: 4.1–23.1%; CV: 3.3–20.0%). However, the 20 Hz LPS demonstrated superior validity and reliability overall (TEE: 1.0–6.0%; CV: 0.7–5.0% and TEE: 2.1–9.2%; CV: 1.6–7.3%). For the 10 Hz GPS, 18 Hz GPS, and 20 Hz LPS, the relative loss of data sets due to measurement errors was 10.0%, 20.0%, and 15.8%, respectively. This study shows that 18 Hz GPS has enhanced validity and reliability for determining movement patterns in team sports compared to 10 Hz GPS, whereas 20 Hz LPS had superior validity and reliability overall. However, compared to 10 Hz GPS, 18 Hz GPS and 20 Hz LPS technologies had more outliers due to measurement errors, which limits their practical applications at this time.

Phosphocreatine (PCr) repletion following either single (1x6 s, n=7) or repeated (5x6 s, departing every 30 s, n=8) maximal short sprint cycling efforts was measured in separate groups of trained subjects. Muscle biopsies (vastus lateralis) were taken pre‐exercise before warming up, and then at 10 s, 30 s and 3 min post‐exercise. After the 1 × 6 s sprint PCr concentration was respectively, 55% (10 s; P<0.01), 69% (30 s; P<0.01) and 90% (3 min; NS) of the pre‐exercise value (mean±SD) (81.1±7.4 mmol · kg−1 DM), whereas after the 5 × 6 s sprints, PCr concentration was, respectively, 27% (10 s; P<0.01), 45% (30 s; P<0.01) and 84% (3 min; P<0.01) of the pre‐exercise value (77.1±4.9 mmol · kg−1 DM). PCr concentration was correlated with muscle lactate at 30 s (r=−0.82; P<0.05) and 3 min of recovery (r=−0.94; P<0.01) for the 1 × 6 s sprint, but not for the 5 × 6 s sprints. The extent of PCr repletion was significantly greater after the 5 × 6 s sprints than the 1 × 6 s sprint between both 10 s and 30 s and 30 s and 3 min, despite lower PCr levels at 10 s, 30 s and 3 min following the 5 × 6 s sprints. Full repletion of PCr is likely to take longer after repeated sprints than single short sprints because of a greater degree of PCr depletion, such that replenishment must commence from lower PCr levels rather than because of slower rates of repletion.

The purpose of this study was to ascertain the typical metabolic power characteristics of elite men's hockey, and whether changes occur within matches and throughout an international tournament. National team players (n = 16), divided into 3 positional groups (strikers, midfielders, defenders), wore Global Positioning System devices in 6 matches. Energetic (metabolic power, energy expenditure) and displacement (distance, speed, acceleration) variables were determined, and intensity was classified utilising speed, acceleration and metabolic power thresholds. Midfielder's average metabolic power (11.8 ± 1.0 W · kg) was similar to strikers (11.1 ± 1.3 W · kg) and higher than defenders (10.8 ± 1.2 W · kg, P = 0.001). Strikers (29.71 ± 3.39 kJ · kg) expended less energy than midfielders (32.18 ± 2.67 kJ · kg, P = 0.014) and defenders (33.23 ± 3.96 kJ · kg, P < 0.001). Energetic variables did not change between halves or across matches. Across all positions, over 45% of energy expenditure was at high intensity (>20 W · kg). International hockey matches are intense and highly intermittent; however, intensity is maintained throughout matches and over a tournament. In isolation, displacement measures underestimate the amount of high-intensity activity, whereas the integration of instantaneous speed and acceleration provides a more comprehensive assessment of the demands for variable-speed activity typically occurring in hockey matches.

The aim of this study was to quantify the movement patterns of contemporary elite women's water polo match play. Thirty-three player matches (centre, n = 15 and perimeter, n = 18) were analysed using video-based time-motion analysis. Frequency and duration of individual movements and distance swum were assessed. Mean match time and playing time were 69:48 +/- 04.30 min:s and 33:14 +/- 14:40 min:s, respectively. Players performed 330 +/- 158 discrete movements per match, representing a change in movement every 6.2 s. There were 54 +/- 25 high-intensity activities per match, or one every 38.4 s. These findings characterise women's water polo as a high-intensity intermittent sport. Total distance swum per match was 699.3 +/- 296.8 m. Positional differences showed a predominance of wrestling in centre players (4:13 vs. 1:53 min:s; P < 0.001) and sprint swimming in perimeter players (2:09 vs. 0:52 min:s; P < 0.001). Players performed 6.7 +/- 3.5 repeated high-intensity activity bouts per match, suggesting that this facet of play is important in water polo. Overall, exercise intensity decreased as a match progressed, suggesting the likelihood of fatigue during the latter stages. These findings provide important information for the planning and monitoring of training in women's water polo.

The strong relationship between these variables suggests that PL in hockey is mostly accumulated through running and other locomotor actions, such that PL is not effective in quantifying other activities (evasion, low stance) that contribute to physiological demands, particularly in training.