The aims of this study were to describe the internal and external match loads (ML) of refereeing activity during official soccer matches and to investigate the relationship among the methods of ML quantification across a competitive season. A further aim was to examine the usefulness of differential perceived exertion (dRPE) as a tool for monitoring internal ML in soccer referees. Twenty field referees (FRs) and 43 assistant referees (ARs) participated in the study. Data were collected from 30 competitive matches (FR = 20 observations, AR = 43 observations) and included measures of internal (Edwards’ heart-rate-derived training impulse [TRIMPEDW]) ML, external (total distance covered, distance covered at high speeds, and player load) ML, and ML differentiated ratings of perceived respiratory (sRPEres) and leg-muscle (sRPEmus) exertion. Internal and external ML were all greater for FRs than for ARs (–19.7 to –72.5), with differences ranging from very likely very large to most likely extremely large. The relationships between internal-ML and external-ML indicators were, in most cases, unclear for FR (r < .35) and small to moderate for AR (r < .40). The authors found substantial differences between RPEres and RPEmus scores in both FRs (0.6 AU; ±90% confidence limits 0.4 AU) and ARs (0.4; ±0.3). These data demonstrate the multifaceted demands of soccer refereeing and thereby highlight the importance of monitoring both internal and external ML. Moreover, dRPE represents distinct dimensions of effort and may be useful in monitoring soccer referees’ ML during official matches.
Daniel Castillo, Matthew Weston, Shaun J. McLaren, Jesús Cámara and Javier Yanci
Jamie Highton, Thomas Mullen, Jonathan Norris, Chelsea Oxendale and Craig Twist
This aim of this study was to examine the validity of energy expenditure derived from microtechnology when measured during a repeated-effort rugby protocol. Sixteen male rugby players completed a repeated-effort protocol comprising 3 sets of 6 collisions during which movement activity and energy expenditure (EEGPS) were measured using microtechnology. In addition, energy expenditure was estimated from open-circuit spirometry (EEVO2). While related (r = .63, 90%CI .08–.89), there was a systematic underestimation of energy expenditure during the protocol (–5.94 ± 0.67 kcal/min) for EEGPS (7.2 ± 1.0 kcal/min) compared with EEVO2 (13.2 ± 2.3 kcal/min). High-speed-running distance (r = .50, 95%CI –.66 to .84) was related to EEVO2, while PlayerLoad was not (r = .37, 95%CI –.81 to .68). While metabolic power might provide a different measure of external load than other typically used microtechnology metrics (eg, high-speed running, PlayerLoad), it underestimates energy expenditure during intermittent team sports that involve collisions.
Dean J. McNamara, Tim J. Gabbett, Geraldine Naughton, Patrick Farhart and Paul Chapman
This study investigated key fatigue and workload variables of cricket fast bowlers and nonfast bowlers during a 7-wk physical-preparation period and 10-d intensified competition period.
Twenty-six elite junior cricketers (mean ± SD age 17.7 ± 1.1 y) were classified as fast bowlers (n = 9) or nonfast bowlers (n = 17). Individual workloads were measured via global positioning system technology, and neuromuscular function (countermovement jump [relative power and flight time]), endocrine (salivary testosterone and cortisol concentrations), and perceptual well-being (soreness, mood, stress, sleep quality, and fatigue) markers were recorded.
Fast bowlers performed greater competition total distance (median [interquartile range] 7049  m vs 5062  m), including greater distances at low and high speeds, and more accelerations (40  vs 19 ) and had a higher player load (912  arbitrary units vs 697  arbitrary units) than nonfast bowlers. Cortisol concentrations were higher in the physical-preparation (mean ± 90% confidence intervals, % likelihood; d = –0.88 ± 0.39, 100%) and competition phases (d = –0.39 ± 0.30, 85%), and testosterone concentrations, lower (d = 0.56 ± 0.29, 98%), in the competition phase in fast bowlers. Perceptual well-being was poorer in nonfast bowlers during competition only (d = 0.36 ± 0.22, 88%). Differences in neuromuscular function between groups were unclear during physical preparation and competition.
These findings demonstrate differences in the physical demands of cricket fast bowlers and nonfast bowlers and suggest that these external workloads differentially affect the neuromuscular, endocrine, and perceptual fatigue responses of these players.
Ademir F.S. Arruda, Christopher Carling, Vinicius Zanetti, Marcelo S. Aoki, Aaron J. Coutts and Alexandre Moreira
To analyze the effects of a very congested match schedule on the total distance (TD) covered, high-intensity-running (HIR) distance, and frequency of accelerations and body-load impacts (BLIs) performed in a team of under-15 soccer players (N = 10; 15.1 ± 0.2 y, 171.8 ± 4.7 cm, 61 ± 6.0 kg) during an international youth competition.
Using global positioning systems, player performances were repeatedly monitored in 5 matches performed over 3 successive days.
Significant differences were observed between matches (P < .05) for the frequency of accelerations per minute, BLIs, and BLIs per minute. No differences were observed for the TD covered, TD run per minute, number of high-intensity runs, distance covered in HIR, per-minute peak running speed attained, or frequency of accelerations. The frequency of accelerations per minute decreased across the competition while BLIs were higher during the final than in all other matches.
These results suggest that BLIs and acceleration might be used as an alternative means to represent the external load during congested match schedules rather than measures related to running speed or distance covered.
Marco Cardinale and Matthew C. Varley
The need to quantify aspects of training to improve training prescription has been the holy grail of sport scientists and coaches for many years. Recently, there has been an increase in scientific interest, possibly due to technological advancements and better equipment to quantify training activities. Over the last few years there has been an increase in the number of studies assessing training load in various athletic cohorts with a bias toward subjective reports and/or quantifications of external load. There is an evident lack of extensive longitudinal studies employing objective internal-load measurements, possibly due to the cost-effectiveness and invasiveness of measures necessary to quantify objective internal loads. Advances in technology might help in developing better wearable tools able to ease the difficulties and costs associated with conducting longitudinal observational studies in athletic cohorts and possibly provide better information on the biological implications of specific external-load patterns. Considering the recent technological developments for monitoring training load and the extensive use of various tools for research and applied work, the aim of this work was to review applications, challenges, and opportunities of various wearable technologies.
Matthias W. Hoppe, Christian Baumgart, Jutta Bornefeld, Billy Sperlich, Jürgen Freiwald and Hans-Christer Holmberg
The aims of this study were (1) to assess the running activities of adolescent tennis players during match play with respect to velocity, acceleration, and deceleration; (2) to characterize changes in these activities during the course of a match; and (3) to identify potential differences between winners and losers. Twenty well-trained adolescent male athletes (13 ± 1 y) played one simulated match each (giving a total of 10 matches), during which distances covered at different velocity categories (0 to < 1, 1 to < 2, 2 to < 3, 3 to < 4, and ≥ 4 m·s−1) and number of running activities involving high velocity (≥ 3 m·s−1), acceleration (≥ 2 m·s−2), and deceleration (≤ −2 m·s−2) were monitored using a global positioning system (10 Hz). Heart rate was also assessed. The total match time, total distance covered, peak velocity, and mean heart rate were 81.2 ± 14.6 min, 3362 ± 869 m, 4.4 ± 0.8 ms−1, and 159 ± 12 beats min−1, respectively. Running activities involving high acceleration (0.6 ± 0.2 n·min−1) or deceleration (0.6 ± 0.2 n·min−1) were three times as frequent as those involving high velocity (0.2 ± 0.1 n·min−1). No change in the pattern of running activities (P ≥ .13, d ≤ 0.39) and no differences between winners and losers (P ≥ .22, d ≤ 0.53) were evident during match play. We conclude that training of well-trained adolescent male tennis players need not focus on further development of their running abilities, since this physical component of multifactorial tennis performance does not change during the course of a match and does not differ between the winners and losers.
Nicola Marsh, Nick Dobbin, Craig Twist and Chris Curtis
This study assessed energy intake and expenditure of international female touch players during an international tournament. Energy intake (food diary) and expenditure (accelerometer, global positioning system) were recorded for 16 female touch players during a four-day tournament, competing in 8.0 ± 1.0 matches; two on Days 1, 2, and 4, and three on Day 3. Total daily energy expenditure (43.6 ± 3.1 Kcal·kg-1 body mass (BM)) was not different (p > .05) from energy intake (39.9 ± 9.4 Kcal·kg-1 BM). Carbohydrate intakes were below current recommendations (6–10 g·kg-1 BM) on Days 1 (4.4 ± 0.6 g·kg-1 BM) and 3 (4.7 ± 1.0 g·kg-1 BM) and significantly below (p < .05) on Day 2 (4.1 ± 1.0 g·kg-1 BM). Protein and fat intakes were consistent with recommendations (protein, 1.2–2.0 g·kg-1 BM: fat, 20–35% total Kcal) across Days 1–3 (protein, 1.9 ± 0.8, 2.2 ± 0.8, and 2.0 ± 0.7 g·kg-1 BM; fat, 35.6 ± 6.8, 38.5 ± 6.4, and 35.9 ± 5.4% total Kcal). Saturated fat intakes were greater (p < .05) than recommendations (10% total Kcal) on Days 1–3 (12.4 ± 2.9, 14.2 ± 5.1, and 12.7 ± 3.5% total Kcal). On average, female touch players maintained energy balance. Carbohydrate intakes appeared insufficient and might have contributed to the reduction (p < .05) in high-intensity running on Day 3. Further research might investigate the applicability of current nutrition recommendations and the role of carbohydrate in multimatch, multiday tournaments.
Cloe Cummins and Rhonda Orr
To investigate the impact forces of collision events during both attack and defense in elite rugby league match play and to compare the collision profiles between playing positions.
26 elite rugby league players.
Player collisions were recorded using an integrated accelerometer in global positioning system units (SPI-Pro X, GPSports). Impact forces of collisions in attack (hit-ups) and defense (tackles) were analyzed from 359 files from outside backs (n = 78), adjustables (n = 97), wide-running forwards (n = 136), and hit-up forwards (n = 48) over 1 National Rugby League season.
Hit-up forwards were involved in 0.8 collisions/min, significantly more than all other positional groups (wide-running forwards P = .050, adjustables P = .042, and outside backs P = .000). Outside backs experienced 25% fewer collisions per minute than hit-up forwards. Hit-up forwards experienced a collision within the 2 highest classifications of force (≥10 g) every 2.5 min of match play compared with 1 every 5 and 9 min for adjustables and outside backs, respectively. Hit-up forwards performed 0.5 tackles per minute of match play, 5 times that of outside backs (ES = 1.90; 95% CI [0.26,3.16]), and 0.2 hit-ups per minute of match play, twice as many as adjustables.
During a rugby league match, players are exposed to a significant number of collision events. Positional differences exist, with hit-up and wide-running forwards experiencing greater collision events than adjustables and outside backs. Although these results may be unique to the individual team’s defensive- and attacking-play strategies, they are indicative of the significant collision profiles in professional rugby league.
Tyler L. Goodale, Tim J. Gabbett, Ming-Chang Tsai, Trent Stellingwerff and Jeremy Sheppard
To evaluate the effects of contextual game factors on activity and physiological profiles of international-level women’s rugby sevens players.
Twenty international-level female rugby sevens players from the same national team participated in this study. Global positioning system and heart-rate data were collected at 5 World Rugby Women’s Sevens Series events (2013–14 season).
Total, moderate-speed (0.2–3.5 m/s), and high-speed running (3.5–5.0 m/s) distances were significantly greater in the first half (20.1% ± 4.1%, 17.6% ± 6.9%, 24.5% ± 7.8%), during losses (11.4% ± 6.1%, 6.1% ± 6.4%, 26.9% ± 9.8%), during losses of large magnitudes (≥2 tries) (12.9% ± 8.8%, 6.8% ± 10.0%, 31.2% ± 14.9%), and against top-4 opponents (12.6% ± 8.7%, 11.3% ± 8.5%, 15.5% ± 13.9%). In addition, total distance increased (5.0% ± 5.5%) significantly from day 1 to day 2 of tournaments, and very-high-speed (5.0–6.5 m/s) running distance increased significantly (26.0% ± 14.2%) during losses. Time spent between 90% and 100% of maximum heart rate (16.4% ± 14.5%) and player load (19.0% ± 5.1%) were significantly greater in the second half. No significant differences in physiological or activity profiles were observed between forwards and backs.
Game half, game outcome, tournament day, opponent rank, and margin of outcome all affected activity profiles, whereas game half affected physiological profiles. No differences in activity or physiological profiles were found between playing positions. Practitioners are advised to develop high-speed running ability in women’s rugby sevens players to prepare them to tolerate the varying factors that affect activity profiles.
Aaron T. Scanlan, Daniel M. Berkelmans, William M. Vickery and Crystal O. Kean
Cricket is a popular international team sport with various game formats ranging from long-duration multiday tests to short-duration Twenty20 game play. The role of batsmen is critical to all game formats, with differing physiological demands imposed during each format. Investigation of the physiological demands imposed during cricket batting has historically been neglected, with much of the research focusing on bowling responses and batting technique. A greater understanding of the physiological demands of the batting role in cricket is required to assist strength and conditioning professionals and coaches with the design of training plans, recovery protocols, and player-management strategies. This brief review provides an updated synthesis of the literature examining the internal (eg, metabolic demands and heart rate) and external (eg, activity work rates) physiological responses to batting in the various game formats, as well as simulated play and small-sided-games training. Although few studies have been done in this area, the summary of data provides important insight regarding physiological responses to batting and highlights that more research on this topic is required. Future research is recommended to combine internal and external measures during actual game play, as well as comparing different game formats and playing levels. In addition, understanding the relationship between batting technique and physiological responses is warranted to gain a more holistic understanding of batting in cricket, as well as to develop appropriate coaching and training strategies.