Association of prospective lower extremity musculoskeletal injury and musculoskeletal, balance, and physiological characteristics in Special Operations Forces.

OBJECTIVES: Previous research has examined lower extremity (LE) musculoskeletal injury (MSI) patterns and risk factors in Special Operations Forces (SOF) trainees, conventional military personnel, and athletes; however, it is unclear if SOF have the same patterns/risk factors. This study aimed to determine the association of musculoskeletal, balance, and physiological characteristics with LE MSI in SOF. DESIGN: Cohort study. METHODS: A total of 726 Air Force (N=140), Navy Sea, Air, and Land (N=301), and Special Warfare Combatant Crewmen (N=285) SOF (age=25.72±4.77years, height=178.34±6.63cm, weight=84.28±9.03kg) participated in laboratory testing, including: LE muscular strength and flexibility; balance; body composition; anaerobic power/capacity; and aerobic capacity. Medical charts were reviewed for LE MSI 365days following laboratory testing. Participants were assigned by injury status and laboratory data stratified by tertile. Chi-square statistics were calculated to determine the frequency of LE MSI across tertiles for each characteristic. RESULTS: There was a significant association between LE MSI and: ankle inversion strength (weaker side: Χ(2)=17.703; stronger side: Χ(2)=18.911; p≤0.001); ankle eversion/inversion strength ratio (lower side: Χ(2)=13.456; higher side: Χ(2)=16.885; p≤0.001); hamstring flexibility (less flexible: Χ(2)=19.930; more flexible Χ(2)=15.185; p≤0.001); gastrocnemius-soleus flexibility (less flexible: Χ(2)=7.889, p=0.019); dynamic balance asymmetry (Χ(2)=7.444, p=0.024); Vestibular and Preference ratios (Χ(2)=9.124, p=0.010 and Χ(2)=6.572, p=0.037, respectively); and aerobic capacity (Χ(2)=13.935, p=0.001). CONCLUSIONS: Characteristics associated with LE MSI are unique in SOF. Human performance program initiatives should include efforts to optimize ankle strength and flexibility, maintain moderate hamstring flexibility, expand dynamic balance strategies, and maximize aerobic capacity to reduce LE MSI risk.

Epidemiology of musculoskeletal injuries sustained by Naval Special Forces Operators and students.

OBJECTIVES: The aim of this analysis was to describe the incidence and common types of medical chart-reviewed musculoskeletal injuries, among four distinct groups of Naval Special Warfare (NSW) personnel: Sea, Air, and Land (SEAL) Operators, SEAL Qualification Training (SQT) students, Special Warfare Combatant-craft Crewman (SWCC) Operators, and Crewman Qualification Training (CQT) students. DESIGN: Descriptive cross-sectional study. METHODS: Medical records were reviewed for 920 NSW personnel. MSI were described and classified by frequency and incidence; anatomic location; injury type and cause; activity during injury; and potential for prevention. RESULTS: The frequency of MSI was 23.1, 46.5, 31.6, and 17.0 per 100 participants per year among SEAL, SQT, SWCC, and CQT, respectively. Upper extremity MSI were the most common in SEAL, lower extremity MSI were common in the other groups. The most frequent MSI anatomic sub-locations varied across groups (SEAL: shoulder, 21.6% of MSI; SQT: foot and toes, 17.0%; SWCC: lumbopelvic spine, 21.7%; and CQT: knee, 30.3%). Pain/spasm/ache were the most common MSI type in SEAL (29.7%) and SWCC (21.7%), tendonitis/tenosynovitis/tendinopathy was the most common MSI type in SQT (21.0%), and tendonitis/tenosynovitis/tendinopathy and fracture were the most common in CQT (15.2% each). A considerable proportion of MSI were classified as potentially preventable-SEAL: 35.1%, SQT: 53.0%, SWCC: 36.7%, and CQT: 21.2%. CONCLUSIONS: MSI cause considerable morbidity among NSW Operators and students, with distinct patterns of distribution by anatomic location and injury type. Since many injuries may be preventable, targeted interventions may be able to mitigate MSI risk.