FSI Football Science Update


Contextualised high-intensity running profiles of elite football players with reference to general and specialised tactical roles.

Ju W, Doran D, Hawkins R, Evans M, Laws A, Bradley PS.

Biol Sport. 2023 Jan;40(1):291-301. doi: 10.5114/biolsport.2023.116003. Epub 2022 May 10

This study on 244 English Premier League players tracking data found that, compared with other positions, Central Offensive Players covered more distance at high-intensity (> 19.8 km · h-1) when performing actions such as ‘Break into Box’, Run in Behind/Penetrate’, and ‘Close Down/Press’, Wide Offensive Players when performing ‘Run with Ball’, Wide Deffensive Players when performing ‘Over/Underlap’, and Deffensive players when performing ‘Covering’. A contextualised physical-tactical analysis may assist coaches and practitioners when designing position or even player-specific training drills.


Effects of pitch size on soccer players’ physiological, physical, technical, and tactical responses during small-sided games: a meta-analytical comparison.

Clemente FM, Praça GM, Aquino R, Castillo D, Raya-González J, Rico-González M, Afonso J, Sarmento H, Silva AF, Silva R, Ramirez-Campillo R.

Biol Sport. 2023 Jan;40(1):111-147. doi: 10.5114/biolsport.2023.110748. Epub 2022 Jan 21

This systematic review with meta-analysis of 41 final articles found that, independent of SSG format and age group, SSGs played on larger pitches induced greater values for heart rate, rate of perceived exertion, total distance, high-speed running, stretch index and surface area. No significant differences were found between pitch size regarding the numbers of accelerations, decelerations, passes, dribbles or positional centroid. These results were found independent of format and age group.


A review of machine learning applications in soccer with an emphasis on injury risk.

Nassis GP, Verhagen E, Brito J, Figueiredo P, Krustrup P.

Biol Sport. 2023 Jan;40(1):233-239. doi: 10.5114/biolsport.2023.114283. Epub 2022 Mar 16

This narrative review paper argues that regarding injuries, machine learning does not seem to have a high predictive ability at the moment (models specificity ranged from 74.2%-97.7%. sensitivity from 15.2%-55.6% with area under the curve of 0.66-0.83). It seems, though, that machine learning can help to identify the early signs of elevated risk for a musculoskeletal injury.


Injury incidence and risk factors in youth soccer players: a systematic literature review. Part I: epidemiological analysis.

Mandorino M, Figueiredo AJ, Gjaka M, Tessitore A.

Biol Sport. 2023 Jan;40(1):3-25. doi: 10.5114/biolsport.2023.109961. Epub 2022 Jan 3

This systematic literature review found that: (1) injury incidence is higher in older players and during matches than during training; (2) sex and maturity status may increase risk of injury; (3) male soccer players are more prone to muscle strains and ligament sprains while female players suffer more ligament sprains; (4) most injuries are located in the ankle and thigh in young male soccer players, and in the ankle and knee in female players; (5) severe injuries are less frequent but the incidence increases in older players.


Injury incidence and risk factors in youth soccer players: a systematic literature review. Part II: Intrinsic and extrinsic risk factors.

Mandorino M, Figueiredo AJ, Gjaka M, Tessitore A.

Biol Sport. 2023 Jan;40(1):27-49. doi: 10.5114/biolsport.2023.109962. Epub 2022 Jan 3

This systematic literature review found that:(1) alteration in neuromuscular control such as limb asymmetry and dynamic knee valgus are important intrinsic risk factors; (2) maturation status may impair neuromuscular control and increase the risk of injury; (3) fatigue and poor recovery contribute to the onset of overuse injuries; (4) the impact of anthropometric factors is still unclear; (5) previous injuries increase the risk of re-injuries; (6) highly skilled players are more exposed to risk of injuries; (7) high external workloads increase the risk of injuries; (8) playing position, as well as sport specialization, exposes young soccer players to greater injury risk. Many factors (e.g., neuromuscular control, training load, maturity status) can modify the susceptibility to injury in young soccer players.


Hamstring muscle architecture and myotonometer measurements in elite professional football players with a prior strained hamstring.

Núñez FJ, Martínez JC, Overberg JA, Torreno N, Suarez-Arrones L.

Biol Sport. 2023 Jan;40(1):93-99. doi: 10.5114/biolsport.2023.112092. Epub 2022 Jan 3

This study using Myotonometry (MyotonPRO) and ultrasound in 7 professional football players that had suffered biceps femoris long head injury BFlh during the previous season found that, compared with 8 non-injured players, these players showed higher frequency, stiffness, decrement, relaxation and creep at the distal BFlh than in the common tendon and proximal BFlh; and higher frequency and stiffness, and lower relaxation and creep in the dominant BFlh, with these findings showing a higher intrinsic tension and a poorer capacity to deform. There were no significant differences between the fascicle length and angle of pennation.


Anterior cruciate ligament ruptures in Spanish soccer first division: An epidemiological retrospective study.

Requejo-Herrero P, Pineda-Galan C, Medina-Porqueres I.

Knee. 2023 Jan 9;41:48-57. doi: 10.1016/j.knee.2022.11.014. Online ahead of print

This retrospective epidemiological study using the Transfermarkt and Besoccer online electronic databases between the 2011 and 2020 (ten) seasons found 110 ACL ruptures registered, with 15.45% of them being re-injuries. This represent an average of 11 ACL tears per season with approximately one ACL injury per team every two seasons, and an incidence rate of 0.0364 per 1000 h of total play with a 68-fold risk in matches compared with training, and higher incidence in September-October and March-April. Predominant injury mechanism was non-contact (56.36%) and the mean lay-off time was 218.8 days.


Effectiveness of Conservative Interventions After Acute Hamstrings Injuries in Athletes: A Living Systematic Review.

Afonso J, Olivares-Jabalera J, Fernandes RJ, Clemente FM, Rocha-Rodrigues S, Claudino JG, Ramirez-Campillo R, Valente C, Andrade R, Espregueira-Mendes J.

Sports Med. 2023 Jan 9. doi: 10.1007/s40279-022-01783-z. Online ahead of print

This systematic review of a final 14 studies comprising 730 athletes (mostly men with ages between 14 and 49 years) from different sports found that no single exercise-based intervention or combination of interventions proved superior in achieving a faster or reducing the risk of reinjury. Only eccentric lengthening exercises showed limited evidence in allowing a shorter time to return to full training TRFT. The platelet-rich plasma treatment did not consistently reduce the TRFT or have any effect on the risk of new hamstrings injuries.


Changes in the Mechanical Properties of the Horizontal Force-Velocity Profile during a Repeated Sprint Test in Professional Soccer Players.

Hermosilla-Palma F, Loro-Ferrer JF, Merino-Muñoz P, Gómez-Álvarez N, Bustamante-Garrido A, Cerda-Kohler H, Portes-Junior M, Aedo-Muñoz E.

Int J Environ Res Public Health. 2022 Dec 30;20(1):704. doi: 10.3390/ijerph20010704

This study in 17 first-division Chilean soccer players that completed a repeated sprint protocol consisting of 8 sprints of 30 m with 25-s pauses between repetitions recorded and analyzed with the MySprint® application found that the horizontal force-velocity profile variables affected by fatigue were those associated with the production of force at high speeds (theoretical max speed V0, decrease of ratio of force DRF, and maximum power Pmax), while those that contribute to the generation of force at the beginning of the sprint (theoretical maximal horizontal force F0 and ratio of force peak) do not present essential variations.