[Purpose] To determine the relationship between low back pain and a range of demographic, environmental, and injury history factors to identify potential factors for the management of low back pain. [Participants and Methods] The participants were 123 elite high school male and female volleyball players. They answered an extensive questionnaire regarding demographic details, low back pain in the previous year, volleyball-specific movements, previous regional injuries, and years of volleyball experience. Questionnaire responses were analyzed. Data were analyzed using a multivariate logistic regression analysis using the presence and absence of low back pain within 1 year as the explanatory variable. [Results] Of the 123 volleyball players, 48.0% reported low back pain. The volleyball-specific movements that induced pain were diverse (e.g., spike, serve, and pass) with no common factor. The factors associated with low back pain were an ankle injury within the previous year and years of volleyball experience. [Conclusion] The associations found in this survey indicate that particular attention should be given to more experienced players with a history of ankle injury to manage low back pain in high school volleyball players.

Low back pain (LBP) is a typical symptom in volleyball players, yet associated physical function factors have not been identified. This study purpose is to determine the relationship between LBP and physical function factors in order to identify potential factors for the management of LBP. Participants were 123 male and female volleyball players of 15- to 17-year-olds who, completed a questionnaire regarding demographic details, presence of LBP, and years of volleyball experience. Participants were divided into 2 groups based on the presence of current LBP and evaluated on physical function tests. The results of the questionnaire response and physical function test were compared between the 2 groups. Data were analyzed using a multivariate logistic regression analysis with presence and absence of current LBP as the explanatory variable. 11.4% of all participants reported current LBP. Physical function factors associated with current LBP were a positive modified Thomas test, years of volleyball experience and reduced range of motion of shoulder horizontal abduction on the dominant hand side. The associations between physical function factors and LBP found in this survey suggest that attention should be given to more experienced players with decreased flexibility of hip and shoulder flexors on the dominant side in order to manage LBP in high school volleyball players.

Background: In recent years, the functional movement screen (FMS) and FMS training have attracted attention as a means of preventing injury, but no studies have examined the effect of such training in high-school baseball players. The aim of this study was to clarify the effect of FMS training on FMS score, physical function and baseball performance in high-school baseball players. Methods: Subjects in this randomized controlled clinical trial were high-school male baseball players assigned to either an FMS training group (intervention group) or a control group. The intervention group performed FMS training 4 times per week for 12 weeks. FMS ability, physical function, and baseball performance were measured prior to the intervention, 8, 12, and 24 weeks after the intervention in the subjects’ school environment. Results: A total of 71 baseball players aged 15 to 17 years were recruited and assigned to either an intervention group (n = 37) or control group (n = 34). There was no significant difference in the characteristics of participants between the 2 groups. Most FMS scores improved to 12 weeks after continued training. In the intervention group compared with the control group, deep squat, hurdle step, inline lunge, active straight leg raise, trunk stability push-up and rotary stability FMS score, total FMS score and eyes closed single leg stance time significantly increased after 8 weeks of training. While hurdle step, inline lunge, active straight leg raise, trunk stability push-up, total FMS score, and eyes closed single leg stance time significantly increased, pitching ball speed significantly decreased at the end of the 12 week training period. Eyes closed single leg stance time and feeling of fatigue significantly improved 12 weeks after training. The number of subjects who scored less than 14 for the total FMS score in the intervention group compared with control group were significantly less after 8 and 12 weeks of FMS training. Conclusion: FMS training for 8 weeks contributes to improving FMS scores for high-school baseball players, but FMS scores go down if FMS training is not continued. Trial registration: University Hospital Medical Information Network Center, Tokyo, Japan: UMIN000027553. Registered on May 30, 2017.

Shoulder range of motion (ROM) adaptation is common observed among volleyball players, but studies on the shoulder joint function of adolescent athletes are lacking. This study aimed to clarify the prevalence of glenohumeral internal rotation deficit (GIRD) among adolescent players and differences in ROM based on sex. A questionnaire survey and ROM measurements of the shoulder joint and trunk using a plastic goniometer were conducted on 123 volleyball players (63 males and 60 females; mean age, 15.8 years). The prevalence of GIRD was investigated for internal rotation differences of > 10° and total rotation motion of <5°. Questionnaire items and ROM were compared between GIRD and non-GIRD patients, and sex differences in ROM were also presented. Of the participants, 38.2% (n = 47/123) had GIRD. The GIRD group showed a decrease in external rotation on the dominant side (p = 0.003, 1 − beta = 0.84), but this was not associated with a history of shoulder injury. Sex differences in shoulder ROM showed hypomobility in males and hypermobility in females. However, there was no association between shoulder injury and GIRD among adolescent players. There are sex differences in ROM, which should be considered in future studies.

Background: Low back pain (LBP) is a common injury in high school volleyball players. We hypothesized that a prevention program could decrease the incidence of LBP in high school volleyball players. This study was an in-season cluster-randomized controlled trial.Methods: We block-randomized 8 high school volleyball teams comprising 70 players aged 15 to 17 years into the intervention (4 teams, 34 players) and control (4 teams, 36 players) groups. The intervention program consisted of 9 physical function tests as well as 1 or 2 self-selected preventive exercises, including dynamic thoracic mobility, trunk stabilization exercises, and static stretching, performed during warm-up. Both groups were followed up for 4 weeks, during which the incidence of LBP was recorded. Physical function tests (back endurance; spinal and back flexibility; active or passive shoulder and trunk range of motion; ankle joint mobility; and iliopsoas, quadriceps, and hamstrings flexibility) were conducted before and after the intervention.Results: The intervention group had a significantly lower incidence of LBP (8.8%) than the control group (33.3%) (relative risk, 3.78; 95% confidence interval, 1.17-12.23; P = .017, 1 − β = 0.99). Lumbar extension accounted for nearly 70% of LBP incidences. Most players in the intervention group demonstrated improved physical function associated with the exercises. Conclusion:The semi-customized prevention program decreased the incidence of LBP and enhanced the physical function parameter in high school volleyball players. Abbreviations: BB = backbends in a supine position, ER = external rotation, FFD = finger-floor distance, HAB = horizontal abduction, LBP = low back pain, MTT = modified Thomas test, ROM = range of motion.