A novel multifactorial hamstring screening protocol: association with hamstring muscle injuries in professional football (soccer) - a prospective cohort study

Abstract

The aim of this pilot study was to analyze the potential association of a novel multifactorial hamstring screening protocol with the occurrence of hamstring muscle injuries (HMI) in professional football. 161 professional male football players participated in this study (age: 24.6 ± 5.36 years; body-height: 180 ± 7.07 cm; body-mass: 77.2 ± 7.70 kg). During the pre- and mid-season, players performed a screening protocol consisting of 11 tests aimed to evaluate their performance in regards to four main musculoskeletal categories: posterior chain strength, sprint mechanical output, lumbopelvic control and range of motion. Univariable cox regression analysis showed no significant association between the isolated test results and new HMI occurrence during the season (n = 17) (p > 0.05). When including injuries that took place between the pre- and mid-season screenings (~90 days), maximal theoretical horizontal force (F0) was significantly associated with higher HMI risk between pre- and mid-season evaluations (n = 14, hazard ratio; 4.02 (CI95% 1.08 to 15.0, p = 0.04). This study identified that 1) no single screening test was sufficient to identify players at risk of HMI within the entire season, while 2) low F0 was associated with increased risk of HMI when occurring closer to the moment of screening. The present results support the potential relevance of additionally including frequent F0 testing for HMI risk reduction management. Replication studies are needed in larger cohorts for more accurate interpretations on "univariable and multivariable levels levels. Finally, future studies should explore whether improving F0 is relevant within a multifactorial HMI risk reduction approach.

Keywords: Injury prevention; Risk factors; Soccer; Sprinting.

FIG. 1

Range of motion tests. The novel Jurdan test (A, B) is based on a composite score from two measurements; the active maximal knee extension angle and the opposite legs passive hip flexion angle. The ASLR test (C, D) is based on the maximal active straight leg hip flexion angle. Asymmetries are calculated from both tests. Therefore, a total of four tests are analysed within the range of motion category. Figure used with permission from Lahti et al. [14].

FIG. 2

Lumbopelvic control tests. The Walk-test (A, B) is based on a composite score of the sagittal and frontal plane kinematic range of the pelvis during walking. The novel Kick-back test (C, D) is based on a composite score from two measurements; the ipsilateral thigh angle during toe-off and the contralateral thigh angle touchdown. Figure used with permission from Lahti et al. [14].

FIG. 3

Posterior chain strength tests. The hip extensor strength test (A) and the knee flexor strength test (B) measure strength via a maximal voluntary isometric contraction using manual dynamometry. Asymmetries are calculated in both tests. Therefore, a total of four tests are analysed within the posterior chain strength category. Figure used with permission from Lahti et al. [14].

FIG. 4

Sprint mechanical output. Raw velocity data from a radar gun is fitted with an exponential function (A). Thereafter, a sprint force-velocity profile is created (B). The variable of interest is the extrapolated maximal theoretical horizontal force value (In figure B it is 6.03 N · kg^-1). Figure used with permission from Lahti et al. [14].