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Murray, Andrew; Fullagar, Hugh H.K.; Delaney, Jace A.; Sampson, John
2018 Science and Medicine in Football
doi: 10.1080/24733938.2018.1452284
Purpose: To investigate if participation in a higher percentage of preseason sessions affects the injury profile within Division I-A American Collegiate and whether the Bradford Factor (BF) is viable for practitioner use.Methods: A retrospective research design was used. Training load and injury data were collected and analysed for two collegiate American football seasons for 70 players.Results: A total of 184 injuries were sustained across two seasons with 106 resulting in time loss (15.6 ± 5.4 time loss injuries per 1000 h). On average, athletes completed 93 ± 17% of preseason sessions. For injury likelihood in the following week, an increase in accumulated minutes in 7d increased the injury risk by 35%. For non-contact time-loss injuries, preseason completion showed a reduction in injury likelihood of 2% for additional 3 sessions completed. A high BF in preseason (>7) increases the risk compared to a low BF through the in-season period.Conclusion: Preseason completion was not associated with a substantial reduction in injury risk in-season. A clear difference in BF between groups was evident and may provide a practical “flagging” variable. The BF may provide a simple but practically meaningful measure to monitor adaptation.
Enright, Kevin; Morton, James; Iga, John; Lothian, Daniel; Roberts, Simon; Drust, Barry
2018 Science and Medicine in Football
doi: 10.1080/24733938.2017.1411603
Purpose: To assess the reliability of a battery of field tests when performed around habitual training during one micro-cycle of the “in-season” period in youth elite soccer players.Methods: n = 19 English Premier League academy players (mean ± SD: age, 18.3 ± 0.2 years; stature, 1.80 ± 0.05 m; body mass, 76.5 ± 7.5 kg; O2 max, 62.3 ± 4.38 ml · kg−1 · min−1; sum of 8 skinfolds, 64.8 ± 17.4 mm) performed; “1RM half-back squat (HBS)”, “vertical jump” (VJ), “Yo-Yo IR2”, “5, 10 & 20 m, sprint”, change of direction “CoD test”, “repeated sprint ability” assessments around their habitual “in-season” training and match-play on two occasions. Intraclass correlations (ICC), typical errors, coefficient of variations (CV), effect sizes and the smallest difference needed to be considered real (MD) were calculated for each test.Results: Most assessments demonstrated good levels of variability (CV; 0.3–4.3%, ICC; 0.83–0.99). To witness an “almost certain beneficial change” (i.e., >MD), changes of approximately 5% are needed for RSAbest, RSAmean, 10m and 20m sprint, “CoD” and 1RM HBS. Whereas, changes of 9–11.5% for CMJ, 5m sprint and Yo-Yo IR2 are needed.Conclusions: The present training and testing “model” is reliable and could be used when evaluating the fitness of highly trained youth elite soccer players during the “in-season” period.
Scott, Tannath J.; McLaren, Shaun J.; Caia, Johnpaul; Kelly, Vincent G.
2018 Science and Medicine in Football
doi: 10.1080/24733938.2018.1448937
Purpose: The aim of the present study was to examine the reliability and usefulness of a proposed 4-min individualised submaximal shuttle run test (SSRIndiv) in elite rugby league players.Materials and methods: Twenty-two elite rugby league players competing in the National Rugby League competition (23.2 ± 3.4 years, 186.8 ± 5.4 cm, 100.2 ± 8.5 kg) performed the SSRIndiv twice, seven days apart (test–retest design). The SSRIndiv was prescribed as 75% of the average speed during a 1500-m time trial. Exercise heart rate was calculated as the average heart rate (HR) over the final 30 s (HRex). Seated HR recovery (HRR) was recorded at 1- (HRR60) and 2-min (HRR120) post-exercise. Data were analysed with magnitude-based inferences.Results: Test–retest typical errors were moderate for HRex (1.2 percentage points; 90% confidence limits: 1.0–1.7), HRR60 (3.4; 2.7–4.6) and HRR120 (2.9; 2.3–3.9). Intraclass correlation coefficients were extremely high for HRex (0.91; 0.78–0.94) and very high for both HRR60 (0.80; 0.61–0.90) and HRR120 (0.84; 0.69–0.92). Thresholds for an individual change that would be likely small and greater than the typical error were ±1.8 (percentage points), ±4.6 and ±4.1 for HRex, HRR60 and HRR120, respectively.Conclusions: The SSRIndiv demonstrates acceptable reliability in the assessment of HRex and HRR, thus demonstrating its potential usefulness for monitoring fitness and fatigue in elite rugby league players.
Kelly, Vincent G.; Chen, Kexun K.; Oyewale, Michael
2018 Science and Medicine in Football
doi: 10.1080/24733938.2018.1453167
Purpose: The purpose of this study was to investigate the test–retest reliability of a modified 30-15 intermittent fitness test (30-15IFT-28m) with elite wheelchair rugby (WR) players.Materials and methods: Ten elite WR players from the Australian Wheelchair Rugby team attended two testing sessions separated by a minimum of 48 h. In each session, participants completed the 30-15IFT-28m. Participants’ final velocity (V30-15IFT-28m), peak heart rate (HRpeak), blood lactate ([La]b) and rating of perceived exertion (RPE) were recorded.Results: There was high reliability for V30-15IFT-28m (intraclass correlation coefficient [ICC] = 0.99, typical error of measurement [TE] = 1.02, coefficient of variation [CV] = 1.9%), HRpeak (ICC = 0.95, TE = 1.05, CV = 4.5%), [La]b (ICC = 0.98, TE = 1.05, CV = 5.5%) and RPE (ICC = 0.97, TE = 1.03, CV = 3.5%). The smallest worthwhile change was 0.2 km·h−1 which represents less than one level on the test. Significant agreement was found for V30-15IFT-28m, HRpeak and [La]b outcome measures through 95% limits of agreement.Conclusions: The 30-15IFT-28m was found to be a reliable test to monitor anaerobic, aerobic and change of direction performance in WR players and can be used to monitor athletes’ performance and determine the effectiveness of a training program.
Cobb, Nathan M.; Unnithan, Viswanath; McRobert, Allistair P.
2018 Science and Medicine in Football
doi: 10.1080/24733938.2017.1423176
Purpose: The purpose of the study was to assess the validity, objectivity, and reliability of a Soccer-Specific Behaviour Measurement Tool (S-SBMT) in relation to the soccer philosophy of a Category One Premier League soccer academy. Methods: A 30 minute, 8 vs. 8 small-sided game (SSG), played by the U12 squad of the participating academy was used for analyses. Validity was ensured through formulating the S-SBMT definitions with experienced soccer coaches from the same soccer academy. Percentage agreement with a reference value of ±1, 95% Confidence Intervals, median sign and Yule’s Q were used to assess objectivity and reliability. Results: High levels of objectivity were found for the number of passes (98.8% agreement), runs with the ball (97.5% agreement), and goal attempts (100%). Reduced objectivity was apparent for forward zonal transitions (75.3%), along with tackles (70.4%), interceptions, (63%), and loose balls (48.1%). Reliability was tested after 1- and 4-weeks, with levels of percentage agreement found to be above the 85% acceptable threshold for most behaviours (passing = 95.1%, runs with the ball = 92.6%, goal attempts = 100%, tackles = 100%). Conclusions: The study demonstrated acceptable objectivity and reliability for S-SBMT behaviours and these findings demonstrate the potential utility of the S-SBMT in monitoring technical actions in a Category One Premier League soccer academy, and a methodological process for other academies to follow in ensuring the quality of performance data.
Suarez-Arrones, Luis; Petri, Cristian; Maldonado, Rafael Angel; Torreno, Nacho; Munguía-Izquierdo, Diego; Di Salvo, Valter; Méndez-Villanueva, Alberto
2018 Science and Medicine in Football
doi: 10.1080/24733938.2018.1445871
Objective: In soccer players, body fat mass (FM) is commonly estimated by assessment methods such as skinfolds, bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA). The main aim was to cross-validate the 3 field methods for quantifying body fat against a recent model of DXA. Methods: This study involved a group of 18 international-level, elite male soccer players belonging to the squad of a Serie A club in Italy. Results: All skinfold equations (with the exception of Deuremberg) showed large-to-very large positive correlations (r from 0.61 to 0.82, p ≤ 0.01) with DXA, however, BIA %FM data showed unclear relationship. All the sum of skinfolds showed moderate-to-very large positive correlations with DXA (r from 0.46 to 0.79, p values from 0.061 to 0.000). The combination of triceps and iliac crest skinfolds selected by the stepwise procedure explained 78.6% variance in DXA total %FM. Conclusion: All different methods employed in the present study are likely to differ, which prevent their use interchangeably. Almost all the equations showed positive correlations, but with different values in comparison with a recent model of DXA. Finally, the sum of skinfolds appears to be a good alternative when limited time and budged is available.
Brownlee, Thomas E; Murtagh, Conall F; Naughton, Robert J; Whitworth-Turner, Craig M; O’Boyle, Andy; Morgans, Ryland; Morton, James P; Erskine, Robert M; Drust, Barry
2018 Science and Medicine in Football
doi: 10.1080/24733938.2018.1432886
Purpose: The purpose of the present study was to record normative isometric maximum voluntary force (MVF) data at baseline and after an 8-week training period using the isometric mid-thigh pull (IMTP) for English Premier League academy players and a maturation-matched control group.Methods: In total, 155 English Premier League academy players across under 9 to under 21 age groups and 93, maturation-, weight- and height-matched control participants performed an IMTP. In total, 142 and 62 of the elite and control cohorts respectively were retested 8 weeks later following a period of integrated soccer training or physical education lessons. Allometrically scaled (peak force divided by body mass0.66) MVF was recorded. MVF was analysed in three maturity groups based on years from/to age of predicted peak height velocity (PHV): pre-PHV, mid-PHV, and post-PHV in elite and control groups.Results: A small difference was seen in isometric MVF in elite (115.42 ± 21.96 N) compared to control (109.36 ± 29.90 N) at baseline (P = 0.004) though no difference was seen between or within groups after 8 weeks (P > 0.167).Conclusion: Differences in baseline MVF suggest that strength is likely important to elite youth soccer performance though training undertaken by this elite group may be insufficient to elicit adaptation in isometric strength.
2018 Science and Medicine in Football
doi: 10.1080/24733938.2018.1427883
Purpose: To survey practices and perceptions of training load monitoring among soccer coaches and practitioners.Methods: A questionnaire assessed factors influencing training planning, training load practices, and training load feedback and usefulness. The questionnaire was distributed via email and as an online version (Bristol Online Survey Tool) to relevant staff working within elite English Soccer.Results: Respondents represented two groups; those involved with player tactical (coach, n = 94) or physical (practitioner, n = 88) preparation. Coaches worked predominantly with younger players at lower standing clubs while practitioners worked with older players at higher standard clubs. With exception for the influence of current match schedule in training planning, there was coach-practitioner agreement for all training planning questions. There was agreement on some purposes for training load monitoring (maximise fitness, evaluate training) but not others (enhance fitness, reduce injury). For load monitoring methods, the greatest proportion of coach answers was for coach perception (22%); whereas the greatest proportion of practitioner responses was for GPS (22%). Largely, load reports were perceived positively and 84.1% of respondents felt training load monitoring was beneficial to their club.Conclusion: This survey shows coaches and practitioners perceive training load monitoring as worthwhile, with differences in practices and perceptions likely reflecting club infrastructure.
DeWitt, John K; Gonzales, Meghan; Laughlin, Mitzi S; Amonette, William E
2018 Science and Medicine in Football
doi: 10.1080/24733938.2018.1447142
Objectives: This investigation examined relationships between game state and external loading in professional women’s soccer. Methods: Match motion and accelerometer data were collected and used to determine running distance, high-speed distance, number of high-speed runs, number of sprints, and total player load (AU). These data were compared by game state (draw 0–0, leading, trailing, or drawing where the score was not 0–0) and playing position: Full back (FB), center back (CB), center midfield (CM), and forward (FW). Results: External loading was not dependent upon game state for FW. Total distance (d = 0.51–0.54), meterage (d = 0.051–0.55), and total player load (d = 0.32–0.76) were less when leading or trailing than when drawn 0–0 for CM. Total distance (d = 0.45–0.80) and meterage (d = 0.31–0.80) were less when leading or trailing than drawing 0–0 for CB. High-speed distance was greater for CB when trailing than when leading (d = 0.62). Total player load for FB was greater (d = 0.49–1.12) when drawn 0–0 than when leading or trailing. Conclusions: Some external loads in women’s professional soccer players are different by position and game state; fatigue or tactical adjustments may influence loading.
Bennett, Kyle J. M.; Novak, Andrew R.; Pluss, Matthew A.; Stevens, Christopher J.; Coutts, Aaron J.; Fransen, Job
2018 Science and Medicine in Football
doi: 10.1080/24733938.2017.1413246
Purpose: This study adopted an exploratory approach to investigate the use of small-sided games as a talent identification tool to determine youth soccer players’ skill proficiency. Methods: A total of 73 male youth soccer players (age = 13.3 ± 1.2 years) were subdivided into two groups in accordance with their playing level (high-level: n = 36, low-level: n = 37). Within their levels, players completed 4 vs. 4 small-sided games on a 30 × 20 m playing surface under two conditions (condition 1: 5 × 3 min, condition 2: 3 × 5 min). Attempted and completed skill involvements were analysed using retrospective video analysis. Skill proficiency was determined as the total completed involvements relative to amount attempted. Results: Repeated measures multivariate analysis of variance identified that high-level players displayed a significantly greater number of attempted and completed passes, touches, and total skill involvements compared with low-level players. Only the number of attempted passes and total involvements differed between conditions for high-level players. High-level players’ total skill proficiency was significantly greater than their lower level counterparts. Conclusion: This study supports the use of small-sided games as a tool to assess soccer-specific skill proficiency, which coaches and sporting practitioners can apply in a talent identification setting.
Lovell, T. W. J.; Bocking, C. J.; Fransen, J.; Coutts, A. J.
2018 Science and Medicine in Football
doi: 10.1080/24733938.2017.1420208
Objectives: To examine the factors influencing selection into playing levels and playing positions in a school-based soccer programme.Methods: Anthropometry, maturation, physical capacity, technical ability and motor competence were assessed in 216 soccer players (aged 10–16 years) who participated in a school-based soccer programme. Team coaches selected players into playing levels, playing positions and provided subjective ratings of player ability.Results: Multivariate analyses of covariance showed significant large and moderate differences between playing levels (F = 5.336, P < 0.001, η2 = .30) and playing positions (F = 1.974, P = 0.002, η2 = .14) respectively, for a combination of maturation, anthropometry, physical capacity, technical ability and motor competence, when adjusted for chronological age. Discriminant analysis revealed 64.8% of cases could be correctly classified into playing level with a combination of sprint speed, agility, aerobic fitness, technical ability and motor competence. Large differences in subjective coach ratings were found between positions for players in the highest playing level (F = 2.598, P = 0.001, η2 = .16).Conclusions: These findings contribute new evidence to highlight how individual characteristics influence the selection process in recreational youth soccer, which have important implications for talent development pathways in schools, clubs and academies.
Black, Georgia M.; Gabbett, Tim J.; Johnston, Rich D.; Cole, Michael H.; Naughton, Geraldine; Dawson, Brian
2018 Science and Medicine in Football
doi: 10.1080/24733938.2018.1426103
Objective: To investigate the influence of physical fitness on peak periods of match-play.Methods: Forty-three female Australian footballers from three teams wore global positioning system units in matches during one competitive season. The Yo-Yo Intermittent Recovery Test (Level 1) was conducted as an estimate of physical fitness. One-, two-, three-, four- and five-minute rolling periods were analysed in order to determine the “peak” and “subsequent” periods during match-play.Results: Midfielders covered greater distances during peak periods than half-line players (Effect size, ES range = 0.33–0.86; likelihood ≥76%). Nomeaningful differences were reported between positional groups for high-speed distances during the peak periods, with the exception of half-liners covering greater distance during the 1-minute period (ES = 0.38; likelihood = 80%).Higher fitness players covered greater peak total and high-speed (ES range = 0.70–1.16; likelihood ≥94%) distances than lower fitness players, irrespective of position. Higher fitness midfielders covered greater high-speed distances during the 1 to 3-minute subsequent periods than lower fitness midfielders (ES range = 0.46–0.71; likelihood ≥81%). Half-liners with greater Yo-Yo performances covered greater relative total and low-speed (ES range = 0.47–0.70; likelihood ≥76%) distances during the subsequent periods than lower fitness players.Conclusion: Developing physical fitness may enable greater peak and subsequent period performances and improve players’ abilities to maintain higher average match intensities.