31 May FSI Selected Publications of the Week
1. Association of the British Athletic Muscle Injury Classification and anatomic location with return to full training and reinjury following hamstring injury in elite football.
Shamji R, James SLJ, Botchu R, Khurniawan KA, Bhogal G, Rushton A.
Medical Department, Aston Villa FC, Birmingham, UK.
The electronic medical records of all players at an English Premier League club were reviewed over 8 consecutive seasons using the BAMIC. Out of 61 Hamstrings Muscle Injuries HMIs, the intramuscular tendon (BAMIC ‘c’) was involved in 13 (21.3%), with a mean rank time to return to full training TRFT of 36 days compared with 24 days without involvement, and 38.5% reinjury rate compared with 12.5%. Most of the HMIs to the biceps femoris with reinjury (5 out of 9) were in the distal third section related to the distal tendon site involving both the long and short head.
2. Influence of Pitch Size on Short-Term High Intensity Actions and Body Impacts in Soccer Sided Games.
Castillo D, Raya-González J, Yanci J, Manuel Clemente F.
Faculty of Health Sciences, Universidad Isabel I, Burgos, Spain.
This study in 20 U16 soccer players compared five-a-side plus goalkeepers small-sided games (SSGs 38 x 26m, individual interaction space (IIS) per player 100 m2 ) and largesided games (LSGs 53 x 37m IIS 200m2). The results showed no meaningful differences in the total distance and intensity of accelerations and decelerations, but LSGs elicited lower distance covered at medium intensity (2.5 – 4 m·s-2), and greater number of sprints, maximum velocity and body impacts.
3. The influence of randomness on goals in football decreases over time. An empirical analysis of randomness involved in goal scoring in the English Premier League.
Wunderlich F, Seck A, Memmert D.
Institute of Exercise Training and Sport Informatics, German Sport University Cologne, Cologne, NRW, Germany.
This study analyzed all goals (7,263) from the seasons 12/13 to 18/19 of the English Premier League, that were checked for the occurrence of six variables of random influence. Additionally, the influence of nine situational variables was investigated. Results show that randomness was present for almost 50% of all goals, the proportion of random goals decreased over the seven seasons, is more pronounced for weaker teams as well as if the current scoreline is a draw, and depends on the match situation (open play, freekick, corner, penalty). Researchers and practitioners should acknowledge randomness as a crucial factor to distinguish clearly between performance and success, and coaches could even consider the conscious creation of uncontrollable situations as a possible tactic to provoke random influences on goal scoring.
4. Individual acceleration-speed profile in-situ: A proof of concept in professional football players.
Morin JB, Le Mat Y, Osgnach C, Barnabò A, Pilati A, Samozino P, di Prampero PE.
Univ Lyon, UJM-Saint-Etienne, Laboratoire Interuniversitaire de Biologie de la Motricité, EA 7424, F-42023 Saint-Etienne, France. Football Science Institute. Electronic address: firstname.lastname@example.org
This proof-of-concept short communication presents a method to derive the players’ individual acceleration-speed (AS) profile in-situ from global positioning system data collected over several football sessions (without running specific tests). Briefly, raw speed data collected in 16 professional male football players over several training sessions were plotted, and for each 0.2 m/s increment in speed from 3 m/s up to the individual top-speed reached, maximal acceleration output was retained to generate a linear AS profile. Results showed highly linear AS profiles for all players which allowed to extrapolate the theoretical maximal speed and accelerations as the individual’s sprint maximal capacities. Good reliability was observed between AS profiles determined 2 weeks apart for the players tested. This opens the possibility to “test players without testing them”.
5. What Role Do Chronic Workloads Play in the Acute to Chronic Workload Ratio? Time to Dismiss ACWR and Its Underlying Theory.
Impellizzeri FM, Woodcock S, Coutts AJ, Fanchini M, McCall A, Vigotsky AD.
Human Performance Research Centre, Faculty of Health, University of Technology Sydney (UTS), Driver Avenue, Moore Park, Sydney, NSW, 2021, Australia. Football Science Institute email@example.com.
This study used previously published data to generate a contrived workload ratio (ACWR) by dividing the acute load (AL) by fixed and randomly generated chronic loads (CLs), and compared these results to real data, to examine the presence and implications of statistical artifacts. The analyses with original data showed effects compatible with higher injury risk for ACWR, but similar effects were observed by dividing AL by the “contrived” fixed and randomly generated CLs, and even these random ACWRs reduced the variance relative to the original AL and further inflated the odds ratios ORs of injury. It was concluded that ACWR is a rescaling of the explanatory variable (AL, numerator), in turn magnifying its effect estimates and decreasing its variance despite conferring no predictive advantage, suggesting ACWR be dismissed as a framework and model for injury risk estimation.