Identifying Musculoskeletal Injury Risk Before Military Training

Key Highlights

• More than 25 modifiable and nonmodifiable factors were associated with musculoskeletal injury risk during basic combat training.
• MSKI occurred in 49% of women trainees and 51% of men who were trainees.
• Poor sleep, low bone density, high body fat, tobacco use, and low physical fitness were key modifiable risk factors.

In a prospective cohort study of 2988 US Army trainees, researchers identified 27 modifiable and nonmodifiable factors associated with musculoskeletal injury (MSKI) risk during the 10-week basic combat training (BCT) and 6-week follow-up. These findings formed the basis of a risk stratification model designed to guide early screening and tailored interventions. Trainees classified as high risk using this model had significantly increased MSKI incidence compared with those in lower tiers.

Musculoskeletal injuries are common and costly in physically demanding environments, with injury rates in BCT reaching 62% in women and 42% in men. While numerous studies have examined MSKI risk in athletes and military personnel during active service or sports seasons, few have focused on the key pretraining factors that drive injury risk during the initiation of intense physical activity. This gap in evidence limits the ability of clinicians and training personnel to proactively mitigate risk. The present study aimed to develop a quantifiable model to classify MSKI risk at training onset, enabling targeted prevention strategies.

Trainees between the ages of 17 and 41 years of age were enrolled at two US Army BCT sites from 2017 to 2023. Data were collected within the first week of training and included fasting blood draws, body composition assessments via dual-energy x-ray absorptiometry, physical fitness tests, and self-reported surveys on demographics, physical activity, sleep quality, psychological resilience, and injury history. MSKIs were tracked using ICD-10 codes from medical records, and logistic regression models with cross-validation were applied to derive risk prediction algorithms for the total cohort and stratified by sex.

MSKI occurred in 1487 trainees, with 35.7% experiencing more than one injury. Risk factors associated with higher MSKI probability spanned seven domains: demographics, anthropometrics/body composition, nutritional status, medical history, physical activity and fitness history, psychological characteristics, and sleep parameters.

Among modifiable risk factors, lower bone mineral density, higher body fat percentage, tobacco use, poor sleep quality, and low exercise frequency in the 2 months prior to BCT were significantly associated with injury risk. Nonmodifiable risk factors included female sex, older age, and prior injuries such as fractures or concussions. Physical fitness variables like poor long jump performance and participation in nonmultidirectional sports also predicted MSKI. The final model demonstrated moderate accuracy (AUROC 0.701) in predicting MSKI and was used to generate a traffic light–style risk stratification tool.

The current study has several limitations, including a reliance on self-reported survey data, limited generalizability to nonmilitary populations, and lack of differentiation among MSKI types, which may have constrained model performance. Additionally, smaller sample sizes in sex-specific models may have affected variable selection and risk estimation.

“This cohort study presents a tiered approach to identifying persons at increased MSKI risk before the start of a physical training program,” the authors concluded. “Applying a tiered quantification risk metric and incorporating multifactorial interventions from these findings may play a role in reduced MSKI risk.”

Reference
Foulis SA, Proctor SP, Spiering BA, et al. Model for musculoskeletal injury risk factors among us army basic combat trainees. JAMA Netw Open. 2025;8(6):e2513177. Published 2025 Jun 2. doi:10.1001/jamanetworkopen.2025.13177