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Liam Anderson, Patrick Orme, Rocco Di Michele, Graeme L. Close, Jordan Milsom, Ryland Morgans, Barry Drust and James P. Morton

Purpose:

To quantify the accumulative training and match load during an annual season in English Premier League soccer players classified as starters (n = 8, started ≥60% of games), fringe players (n = 7, started 30–60% of games) and nonstarters (n = 4, started <30% of games).

Methods

Players were monitored during all training sessions and games completed in the 2013–14 season with load quantified using global positioning system and Prozone technology, respectively.

Results:

When including both training and matches, total duration of activity (10,678 ± 916, 9955 ± 947, 10,136 ± 847 min; P = .50) and distance covered (816.2 ± 92.5, 733.8 ± 99.4, 691.2 ± 71.5 km; P = .16) were not different between starters, fringe players, and nonstarters, respectively. However, starters completed more (all P < .01) distance running at 14.4–19.8 km/h (91.8 ± 16.3 vs 58.0 ± 3.9 km; effect size [ES] = 2.5), high-speed running at 19.9–25.1 km/h (35.0 ± 8.2 vs 18.6 ± 4.3 km; ES = 2.3), and sprinting at >25.2 km/h (11.2 ± 4.2 vs 2.9 ± 1.2 km; ES = 2.3) than nonstarters. In addition, starters also completed more sprinting (P < .01, ES = 2.0) than fringe players, who accumulated 4.5 ± 1.8 km. Such differences in total high-intensity physical work done were reflective of differences in actual game time between playing groups as opposed to differences in high-intensity loading patterns during training sessions.

Conclusions

Unlike total seasonal volume of training (ie, total distance and duration), seasonal high-intensity loading patterns are dependent on players’ match starting status, thereby having potential implications for training program design.

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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.

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Nick B. Murray, Georgia M. Black, Rod J. Whiteley, Peter Gahan, Michael H. Cole, Andy Utting and Tim J. Gabbett

Purpose:

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.

Methods:

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).

Results:

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%).

Conclusions:

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.

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Thomas Kempton and Aaron J. Coutts

Purpose:

To describe the physical and technical demands of rugby league 9s (RL9s) match play for positional groups.

Methods:

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.

Results:

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.

Conclusions:

Positional differences exist for both physical and technical measures, and preparation for RL9s play should incorporate these differences.

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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.

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Laura A. Garvican, Kristal Hammond, Matthew C. Varley, Christopher J. Gore, Francois Billaut and Robert J. Aughey

Purpose:

This study investigated the decrement in running performance of elite soccer players competing at low altitude and time course for abatement of these decrements.

Methods:

Twenty elite youth soccer players had their activity profile, in a sea-level (SL) and 2 altitude (Alt, 1600 m, d 4, and d 6) matches, measured with a global positioning system. Measures expressed in meters per minute of match time were total distance, low- and high-velocity running (LoVR, 0.01–4.16 m/s; HiVR, 4.17–10.0 m/s), and frequency of maximal accelerations (>2.78 m/s2). The peak and subsequent stanza for each measure were identified and a transient fatigue index calculated. Mean heart rate (HR) during the final minute of a submaximal running task (5 min, 11 km/h) was recorded at SL and for 10 d at Alt. Differences were determined between SL and Alt using percentage change and effect-size (ES) statistic with 90% confidence intervals.

Results:

Mean HR almost certainly increased on d 1 (5.4%, ES 1.01 ± 0.35) and remained probably elevated on both d 2 (ES 0.42 ± 0.31) and d3 (ES 0.30 ± 0.25), returning to baseline at d 5. Total distance was almost certainly lower than SL (ES –0.76 ± 0.37) at d 4 and remained probably reduced on d 6 (ES –0.42 ± 0.36). HiVR probably decreased at d 4 vs SL (–0.47 ± 0.59), with no clear effect of altitude at d 6 (–0.08 ± 0.41). Transient fatigue in matches was evident at SL and Alt, with a possibly greater decrement at Alt.

Conclusion:

Despite some physiological adaptation, match running performance of youth soccer players is compromised for at least 6 d at low altitude.

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Matthew D. Portas, Jamie A. Harley, Christopher A. Barnes and Christopher J. Rush

Purpose:

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.

Methods:

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.

Results:

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%.

Conclusions:

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.

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Kieran Cooke, Tom Outram, Raph Brandon, Mark Waldron, Will Vickery, James Keenan and Jamie Tallent

Purpose: First, to assess changes in neuromuscular function via alterations in countermovement-jump strategy after training and 2 forms of competition and second, to compare the relationship between workloads and fatigue in seam bowlers and nonseam bowlers. Methods: Twenty-two professional cricketers’ neuromuscular function was assessed at baseline, immediately post and +24 h posttraining, and after multiday and 1-day cricket events. In addition, perceptual (rating of perceived exertion [RPE] and soreness) measures and external loads (PlayerLoad™, number of sprints, total distance, and overs) were monitored across all formats. Results: Seam bowlers covered more distance, completed more sprints, and had a higher RPE in training (P < .05), without any difference in soreness compared with nonseam bowlers. Compared with seam bowlers, the nonseam bowlers’ peak force decreased post-24 h compared with baseline only in 1-d cricket (95% CI, 2.1–110.0 N; P < .04). There were no pre–post training or match differences in jump height or alterations in jump strategy (P > .05). Seam bowlers increased their peak jumping force from baseline to immediately posttraining or game (95% CI, 28.8–132.4 N; P < .01) but decreased between postcricket to +24 h (95% CI, 48.89–148.0 N; P < .001). Conclusion: Seam bowlers were more accustomed to high workloads than nonseamers and thus more fatigue resistant. Changes in jump height or strategy do not appear to be effective methods of assessing fatigue in professional crickets. More common metrics such as peak force are more sensitive.

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Jamie E. L. Spinney, Hugh Millward and Darren Scott

Background:

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.

Methods:

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:

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.

Conclusions:

This research highlights the importance of both types of walking, while also casting suspicion on the traditional home-based paradigm used to measure “walkability.”

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Nicola Furlan, Mark Waldron, Mark Osborne and Adrian J. Gray

Purpose:

To assess the ecological validity of the Rugby Sevens Simulation Protocol (R7SP) and to evaluate its interday reliability.

Methods:

Ten male participants (20 ± 2 y, 74 ± 11 kg) completed 2 trials of the R7SP, separated by 7 d. The R7SP comprised typical running and collision activities, based on data recorded during international rugby sevens match play. Heart rate (HR) was monitored continuously during the R7SP, and the participants’ movements were recorded through a 20-Hz global positioning system unit. Blood lactate and rating of perceived exertion were collected before and immediately after the 1st and 2nd halves of the R7SP.

Results:

The average activity profile was 117 ± 5 m/min, of which 27 ± 2 m/min was covered at high speed, with a calculated energetic demand of 1037 ± 581 J/kg, of which ~40% was expended at a rate above 19 W/kg. Mean HR was 88% ± 4% of maximal HR. Participants spent ~45% ± 27% of time above 90% of maximal HR (t >90%HRmax). There were no significant differences between trials, except for lactate between the halves of the R7SP. The majority of the measured variables demonstrated a between-trials coefficient of variation (CV%) lower than 5%. Blood lactate measurements (14–20% CV) and t >90%HRmax (26% CV) were less reliable variables. In most cases, the calculated moderate worthwhile change was higher than the CV%.

Conclusions:

The R7SP replicates the activity profile and HR responses of rugby sevens match play. It is a reliable simulation protocol that can be used in a research environment to detect systematic worthwhile changes in selected performance variables.