. These parameters can be easily obtained from global positioning system (GPS) units attached to players. In particular, the recent and widely use of GPS devices monitors the player’s performance during training sessions and competitions, 17 recording various parameters. This information could help to
Sergio Jiménez-Rubio, Archit Navandar, Jesús Rivilla-García, Víctor Paredes-Hernández and Miguel-Ángel Gómez-Ruano
Matthew Pearce, David H. Saunders, Peter Allison and Anthony P. Turner
. 17 By dividing adolescent leisure-time physical activity into context-based dimensions and combining data from global positioning system (GPS) receivers, diaries, and accelerometers, it may be possible to more accurately characterize the specific contexts where MVPA occurs. Consistent with an
Dan Weaving, Nicholas E. Dalton, Christopher Black, Joshua Darrall-Jones, Padraic J. Phibbs, Michael Gray, Ben Jones and Gregory A.B. Roe
embedment in decision making for coaches during their planning of the training process. 5 In the age of technology, 5 numerous TL methods and variables are now available to practitioners working in team-sports including microtechnology (eg, global positioning systems [GPS]) and the session rating of
Denise Jennings, Stuart J. Cormack, Aaron J. Coutts and Robert J. Aughey
The purpose of this study was to investigate the influence of multiple games on exercise intensity during a world-class hockey tournament.
15 players (mean ± SD age 27 ± 4 y, stature 179 ± 5 cm, body mass 77 ± 5 kg, and estimated VO2 64.2 ± 3.1 mL · kg−1 · min−1) competing in the Champions Trophy (CT). Global-positioning systems assessed total distance (TD), low-speed activity (LSA; 0.10–4.17 m/s), and high-speed running (HSR; >4.17 m/s) distance. Differences in movement demands (TD, LSA, HSR) between positions and matches were assessed using the effect size and percent difference ± 90% confidence intervals. Two levels of comparison were made. First, data from subsequent matches were compared with match 1, and, second, data from each match compared with a tournament average (TA).
In all matches, compared with game 1, midfielders performed less HSR distance. However, the amount of HSR did not decrease as the tournament progressed. When compared with the TA, defenders showed more variation in each match. All positions showed lower movement outputs when the team won by a large margin.
It was possible for elite team-sport athletes to maintain exercise intensity when playing 6 matches in a period of 9 days, contrary to the only other investigation of this in elite male field hockey.
Thomas Kempton and Aaron J. Coutts
To describe the physical and technical demands of rugby league 9s (RL9s) match play for positional groups.
Global positioning system data were collected during 4 games from 16 players from a team competing in the Auckland RL9s tournament. Players were classified into positional groups (pivots, outside backs, and forwards). Absolute and relative physical-performance data were classified as total high-speed running (HSR; >14.4 km/h), very-high-speed running (VHSR; >19.0 km/h), and sprint (>23.0 km/h) distances. Technical-performance data were obtained from a commercial statistics provider. Activity cycles were coded by an experienced video analyst.
Forwards (1088 m, 264 m) most likely completed less overall and high-speed distances than pivots (1529 m, 371 m) and outside backs (1328 m, 312 m). The number of sprint efforts likely varied between positions, although differences in accelerations were unclear. There were no clear differences in relative total (115.6−121.3 m/min) and HSR (27.8−29.8 m/min) intensities, but forwards likely performed less VHSR (7.7 m/min) and sprint distance (1.3 m/min) per minute than other positions (10.2−11.8 m/min, 3.7−4.8 m/min). The average activity and recovery cycle lengths were ~50 and ~27 s, respectively. The average longest activity cycle was ~133 s, while the average minimum recovery time was ~5 s. Technical involvements including tackles missed, runs, tackles received, total collisions, errors, off-loads, line breaks, and involvements differed between positions.
Positional differences exist for both physical and technical measures, and preparation for RL9s play should incorporate these differences.
Nick B. Murray, Georgia M. Black, Rod J. Whiteley, Peter Gahan, Michael H. Cole, Andy Utting and Tim J. Gabbett
Throwing loads are known to be closely related to injury risk. However, for logistic reasons, typically only pitchers have their throws counted, and then only during innings. Accordingly, all other throws made are not counted, so estimates of throws made by players may be inaccurately recorded and underreported. A potential solution to this is the use of wearable microtechnology to automatically detect, quantify, and report pitch counts in baseball. This study investigated the accuracy of detection of baseball pitching and throwing in both practice and competition using a commercially available wearable microtechnology unit.
Seventeen elite youth baseball players (mean ± SD age 16.5 ± 0.8 y, height 184.1 ± 5.5 cm, mass 78.3 ± 7.7 kg) participated in this study. Participants performed pitching, fielding, and throwing during practice and competition while wearing a microtechnology unit. Sensitivity and specificity of a pitching and throwing algorithm were determined by comparing automatic measures (ie, microtechnology unit) with direct measures (ie, manually recorded pitching counts).
The pitching and throwing algorithm was sensitive during both practice (100%) and competition (100%). Specificity was poorer during both practice (79.8%) and competition (74.4%).
These findings demonstrate that the microtechnology unit is sensitive to detect pitching and throwing events, but further development of the pitching algorithm is required to accurately and consistently quantify throwing loads using microtechnology.
Jamie E. L. Spinney, Hugh Millward and Darren Scott
Walking is the most common physical activity for adults with important implications for urban planning and public health. Recreational walking has received considerably more attention than walking for transport, and differences between them remain poorly understood.
Using time-use data collected from 1971 randomly-chosen adults in Halifax, Canada, we identified walking for transport and walking for recreation events, and then computed participation rates, occurrences, mean event durations, and total daily durations in order to examine the participants and timing, while the locations were examined using origin-destination matrices. We compared differences using McNemar’s test for participation rates, Wilcoxon test for occurrences and durations, and Chi-Square test for locations.
Results illustrate many significant differences between the 2 types of walking, related to participants, timing, and locations. For example, results indicate a daily average of 3.1 walking for transport events, each lasting 8 minutes on average, compared with 1.4 recreational walking events lasting 39 minutes on average. Results also indicate more than two-thirds of recreational walks are home-based, compared with less than one-fifth of transport walks.
This research highlights the importance of both types of walking, while also casting suspicion on the traditional home-based paradigm used to measure “walkability.”
Daniel Medina, Eduard Pons, Antonio Gomez, Marc Guitart, Andres Martin, Jairo Vazquez-Guerrero, Ismael Camenforte, Berta Carles and Roger Font
Despite approval of the use of electronic performance-tracking systems (EPTSs) during competition by the International Football Association Board, other team-sport organizations and leagues have banned their use due to “safety concerns,” with no evidence to support this assertion. The aim of the current brief report was to provide empirical evidence to support the widespread use of EPTSs across all sports by examining safety issues concerning their use in a multi-team-sport club. Five outdoor football teams (1st team, 2nd team, under 19 [U-19], under 18 [U-18], and 1st team female) and 3 indoor-sport (basketball, futsal, and handball) teams were monitored, accounting for a total of 63,734 h of training and 12,748 h of game time. A questionnaire was sent to all fitness coaches involved, and the clinical history was reviewed for every medical issue reported. Six minor chest contusions were recorded in female football goalkeepers wearing the frontal chest strap (3.17 episodes per 1000 training h). During training, 3 episodes of minor skin abrasion affecting the thoracic area due to wearing vests too tight were recorded in the U-19 football team (0.21 per 1000 h) and 2 episodes in U-18 (0.39 per 1000 h). It must be noted that none of these episodes resulted in lost days of training or games, and none required medical assistance. In conclusion, empirical evidence confirms that EPTSs are safe to use across team sports.
Matthew D. Portas, Jamie A. Harley, Christopher A. Barnes and Christopher J. Rush
The study aimed to analyze the validity and reliability of commercially available nondifferential Global Positioning System (NdGPS) devices for measures of total distance during linear, multidirectional and soccer-specific motion at 1-Hz and 5-Hz sampling frequencies.
Linear (32 trials), multidirectional (192 trials) and soccer-specific courses (40 trials) were created to test the validity (mean ± 90% confidence intervals), reliability (mean ± 90% confidence intervals) and bias (mean ± 90% confidence intervals) of the NdGPS devices against measured distance. Standard error of the estimate established validity, reliability was determined using typical error and percentage bias was established.
The 1-Hz and 5-Hz data ranged from 1.3% ± 0.76 to 3.1% ± 1.37 for validity and 2.03% ± 1.31 to 5.31% ± 1.2 for reliability for measures of linear and soccer-specific motion. For multidirectional activity, data ranged from 1.8% ± 0.8 to 6.88% ± 2.99 for validity and from 3.08% ± 1.34 to 7.71% ± 1.65 for reliability. The 1-Hz underestimated some complex courses by up to 11%.
1-Hz and 5-Hz NdGPS could be used to quantify distance in soccer and similar field-based team sports. Both 1-Hz and 5-Hz have a threshold beyond which reliability is compromised. 1-Hz also underestimates distance and is less valid in more complex courses.
Liam Anderson, Patrick Orme, Robert J. Naughton, Graeme L. Close, Jordan Milsom, David Rydings, Andy O’Boyle, Rocco Di Michele, Julien Louis, Catherine Hambly, John Roger Speakman, Ryland Morgans, Barry Drust and James P. Morton
In an attempt to better identify and inform the energy requirements of elite soccer players, we quantified the energy expenditure (EE) of players from the English Premier League (n = 6) via the doubly labeled water method (DLW) over a 7-day in-season period. Energy intake (EI) was also assessed using food diaries, supported by the remote food photographic method and 24 hr recalls. The 7-day period consisted of 5 training days (TD) and 2 match days (MD). Although mean daily EI (3186 ± 367 kcals) was not different from (p > .05) daily EE (3566 ± 585 kcals), EI was greater (p < .05) on MD (3789 ± 532 kcal; 61.1 ± 11.4 kcal.kg-1 LBM) compared with TD (2956 ± 374 kcal; 45.2 ± 9.3 kcal.kg-1 LBM, respectively). Differences in EI were reflective of greater (p < .05) daily CHO intake on MD (6.4 ± 2.2 g.kg-1) compared with TD (4.2 ± 1.4 g.kg-1). Exogenous CHO intake was also different (p < .01) during training sessions (3.1 ± 4.4 g.h-1) versus matches (32.3 ± 21.9 g.h-1). In contrast, daily protein (205 ± 30 g.kg-1, p = .29) and fat intake (101 ± 20 g, p = .16) did not display any evidence of daily periodization as opposed to g.kg-1, Although players readily achieve current guidelines for daily protein and fat intake, data suggest that CHO intake on the day before and in recovery from match play was not in accordance with guidelines to promote muscle glycogen storage.