The side hop test: Validity, reliability, and quality aspects in relation to sex, age and anterior cruciate ligament reconstruction, in soccer players

To study the side hop test regarding validity, reliability, and quality in relation to sex, age and ACL-reconstruction in soccer players. Cohort study. 117 females with a primary ACL-reconstruction, and 119 females, 46 males (age 16–26 years), 49 girls and 66 boys (age 13–16 years) without injury. For convergent validity, one physiotherapist analysed side hops live and later on video. One physiotherapist and two physiotherapy students analysed side hops from 92 players for interrater reliability (video). For intrarater reliability, side hops from 35 players were analysed twice (video). Quality aspects (flaws), i.e. number of times the hopping limb touched the strips, the non-hopping limb touched the floor, and double hops/foot turns with the hopping limb, were registered (video). Convergent validity was excellent; the intraclass correlation coefficient (ICC) was 0.93–1.0. All reliability measures were excellent (ICC 0.92−1.0). Adult male players had fewest and girls had most flaws, especially double hops/foot turns with the hopping limb, compared with all other players (mean, 11−12 vs 1−6, η2 = 0.18, large effect size). No differences were reported between knee-healthy and ACL-reconstructed females. The side hop test is valid and reliable. Quality aspects differ between sexes and ages. •The side hop test is a valid and reliable test.•The side hop test can be used in clinical practice without video recording.•Hop techniques differ between sexes and ages.•Adult males had less flaws and youth girls had most flaws.•Hop techniques did not differ between knee-healthy and ACL-reconstructed females.