Injury prevention effects of stretching exercise intervention by physical therapists in male high school soccer players

We aimed to examine the prevalence of injury after physical therapy intervention for muscle tightness and injury prevention in male high school soccer players. A randomized controlled trial was conducted. Participants comprised 124 players from two high schools who competed in national tournament soccer games held from April 2018 to March 2019. Players were randomly divided into intervention (with a 12-week stretching intervention by physical therapists) and control groups (without the intervention). Players and coaches provided written information regarding injuries and daily training and match times; physical therapists visited each team weekly to collect data and review documentation. Muscle tightness and injury incidence, number, type, location, circumstances, situations, severity, and contents during the 12-week intervention period and a subsequent 40-week observation period were compared between groups. Injuries were significantly lower with intervention during the 40-week observation period (P < .01) but not during the 12-week intervention period (P = .44). Injury types mainly included disorder, non-contact, lower-limb/trunk, and muscle/tendon injuries. Significant interactions were observed for all tightness-test measurement items. The intervention group showed significant improvements in heel-buttock distance, and straight leg-raise and hip rotation angles (pre-intervention < 12 weeks < 52 weeks), as well as significant improvements in ankle dorsiflexion angles at 12 and 52 weeks (relative to pre-intervention values). Instructed stretching exercises, personally designed by physical therapists to address muscle tightness, improved the range of motion and trunk flexibility, with a positive effect on the injury rate in male high school soccer players, especially for non-contact disorder injuries during training.