An analysis of pre-season risk factors for low back injury in high-school baseball pitchers: a prospective study

Shoulder stretching versus shoulder muscle strength training for the prevention of baseball-related arm injuries: a randomized, active-controlled, open-label, non-inferiority study

Glenohumeral internal rotation deficit (GIRD) and weakness in prone external rotation are risk factors for shoulder and elbow injuries in high school baseball pitchers. While a shoulder-stretching prevention program to improve GIRD decreases the injury rate, the effects of external rotation strength remain unclear. This non-inferiority (NI) study investigates the hypothesis that external rotation strength training is not inferior to sleeper stretching for shoulder and elbow injury prevention in high school baseball pitchers. Participants were randomly allocated to the stretching (n = 62; active control group) and muscle-training (n = 51) groups. Specific exercises were performed each night. Elbow and shoulder injuries were monitored for 150 days. Kaplan-Meier survival curves were generated, and the hazard ratios (HRs) for injury occurrence were calculated using multivariate Cox regression. The log-rank test was used to compare the injury-free time. A one-sided NI test using a fixed NI margin was performed (significance level, P = 0.025). The injury rates were 22.6% (n = 14) in the stretching group and 9.8% (n = 5) in the muscle-training group. The muscle-training group had a lower injury rate (P < 0.001) and a lower risk of injury than the stretching group (HR = 0.489). Therefore, external rotation muscle strength training is not inferior to stretching for preventing baseball-related arm injuries.

Physical characteristics of patients with symptomatic lumbar spondylolysis who have recurrent low back pain after returning to sports

INTRODUCTION

To determine the physical characteristics of patients with symptomatic lumbar spondylolysis (LS) who have recurrent low back pain after returning to sports.

METHOD

Fifty-three adolescent patients with symptomatic LS participated in this study. Patients with symptomatic LS were assessed for flexibility, trunk muscle strength, and Functional Movement Screen (FMS) score, and then divided into two groups according to the degree of pain experienced one month after returning to sport.

RESULTS

Twenty-four patients returned to their pre-injury sports level without pain (excellent group), while the remaining 29 patients had pain and decreased activity level during sports (pain group). The excellent group had a significantly higher shoulder mobility score on the FMS than the pain group, and the effect size was larger. However, there were no significant differences in body flexibility, muscle tightness, trunk muscle strength, or other FMS items.

DISCUSSION

The most important finding of this study is that patients with LS who have recurrent low back pain after returning to sports are characterized by poor functional upper body movement.

CONCLUSIONS

Because upper body functional movement pattern may be an important factor in the management of patients with symptomatic LS, preventive rehabilitation to enhance upper body mobility and motor control should be considered for these patients.