Timothy C. Sell

Introduction: Special operations combat soldiers (SOCS) are susceptible to cervical spine (CS) injuries as they undergo tactical training and perform missions in demanding environments with head-supported mass (HSM). This HSM, which includes the baseline protective helmet, communications, specialized night vision technology, and other attachments, can weigh more than 3 kg. The purpose of this study was to describe the injury epidemiology of CS injuries in SOCS including the effect that HSM may have on both CS injuries and pain. Materials and Methods: The study population included 284 SOCS and 91 age-matched nonmilitary control subjects. A self-report of CS injury history, which included a description of the cause of the injury and information regarding the HSM relative to the injury was collected from all participants. Participants were asked questions about their military experience, the number of parachute jumps, and HSM exposure. All participants completed a CS pain questionnaire (covering the previous 12 months) and the Neck Disability Index survey. All participants also underwent musculoskeletal testing (strength and range of motion) of the CS. Results: The SOCS reported 1,090 injuries of which 91% occurred while wearing HSM during military activities. Most of these injuries (74.7%) were characterized as sprain or strain and 81.4% were acute (sudden onset). Whiplash (28.5%), followed by parachute opening shock (23.1%), and landing (parachute operations) (23.1%) were the most common injury mechanisms. Treatment was sought in 50% of cases. Eighty-eight percent reported CS pain related to military operational activity during the previous 12 months with parachute opening (69%) listed as the most common task that aggravated neck pain. SOCS with 2 or more injuries, chronic neck pain, or pain in the previous 12 months were typically weaker, had worse range of motion, and worse neck disability. Conclusion: SOCS experience a considerable incidence of CS injuries and frequently report neck pain. Most of these conditions are associated with exposure to HSM and correlate with chronic pain, headaches, difficulties with concentration, and sleep disturbances. Such complications often necessitate medical intervention, may limit duty performance, and could increase susceptibility to further CS injuries. Opportunities for injury prevention exist through policy evaluation and recommendations, equipment assessments, and targeted physical training regimens.

Background: Comparing static postural stability between the involved and uninvolved legs in individuals 12 weeks after ACL reconstruction (ACLR), and against healthy controls, may provide insight into rehabilitation progression. Purpose: To compare static single-leg postural stability between the injured and uninjured legs of individuals 12 weeks post ACLR, and to a control group of healthy, physically active individuals. Study Design: Case-control study Methods: Twenty-nine participants (17 male, 12 female; age = 20.9 ± 5.0) 12 weeks post ACLR and 87 healthy controls (51 male, 36 female; age = 19.4 ± 1.2) volunteered. Static single-leg postural stability was assessed using an AMTI force plate under eyes open (EO) and eyes closed (EC) conditions. Ground reaction force in three directions were recorded for each condition. Comparisons were made between the ACLR group and controls, as well as between the involved and uninvolved legs within the ACLR group. Descriptive statistics were calculated for each variable. Kruskal-Wallis and Wilcoxon signed rank tests identified significant differences, and effect sizes were computed. Results: There were no significant differences within the ACLR group or between the ACLR and control groups for any static postural stability variable. Conclusions: Under the specific static postural stability test administered, individuals 12 weeks post ACLR did not show significant differences in static postural stability between their involved and uninvolved legs, or when compared to healthy controls. These findings suggest that static postural stability is either not significantly impacted by ACLR or that deficits resolve by 12 weeks post-surgery and may not need to be a primary focus of early rehabilitation. Alternatively, it is also possible that the challenge imposed in the current study was not sufficient to challenge the components required for postural stability and clinicians should consider integrating more difficult tasks. Level of Evidence: 3

Special Operations Combat Personnel (SOCP) face significant challenges and occupational demands that put them at significant risk for musculoskeletal injury. Musculoskeletal injury leads to lost-duty days, medical disqualification, and compromises operational readiness and mission success. Optimizing human performance and developing injury prevention strategies can position SOCP for success, but human performance optimization is a complex process that demands the integration of multiple disciplines to address a broad range of capabilities necessary for this success. The Warrior Model for Human Performance Optimization outlines a step-by-step approach to human performance optimization embedded within a scientific, evidenced-based approach to injury prevention and performance optimization that includes a step to ensure specificity of training and interventions. This evidence-based approach can insure that SOCP capabilities match the demands of occupation enabling them to successfully execute their occupation tasks without risk of injury. While the focus of this review is on military personnel, the same principles have application to nonmilitary high-performance athletes.

Internal and external rotational knee stability is essential for sports performance and excessive rotation can lead to injury but is rarely assessed in injury risk analysis. The objectives of this study were to determine the between-session reliability, discriminant validity and potential sex differences of a dynamic postural stability (DPS) assessment that challenges transverse plane knee stability. Thirty-six individuals (21.7 ± 2.6 years) including 19 females (20.8 ± 1.3 years) and 17 males (22.6 ± 3.4 years) participated. We measured DPS during rotational jump tasks (RJT) over 2 test sessions utilising a force plate. Kinematic (motion analysis) and electromyographic measures were compared to a traditional anterior–posterior jump task (APJT) to assess the discriminant validity and comparisons were performed between sexes. The intraclass correlation coefficients were between 0.67 and 0.86. Significant differences in transverse rotation angle at initial contact transverse rotational velocity of the knee were observed between the 2 different RJT and between the RJT and the traditional APJT. No sex differences were observed. The new assessment had good between-session reliability and offers a different challenge than a traditional jump task. This RJT may offer a novel assessment of knee joint rotational stability in conjunction with traditional measures.

Background: Muscle health is recognized for its critical role in the functionality and well-being of older adults. Readily accessible, reliable, and inexpensive methods of measuring muscle health are needed to advance research and clinical care. Methods: In this prospective, blinded study, 27 patients underwent quantitative muscle ultrasound (QMUS), standard electrical impedance myography (sEIM), and handheld electrical impedance myography (hEIM) of the anterior thigh musculature by two independent examiners. Subjects also had dual-energy X-ray absorptiometry (DEXA) scans and standardized tests of physical function and strength. Data were analyzed for intra- and inter-rater reliability, along with correlations with DEXA and physical measures. Results: Measures of intra- and inter-rater reliability were excellent (>0.90) for all QMUS, sEIM, and hEIM parameters except intra-rater reliability of rectus femoris echointensity (0.87–0.89). There were moderate, inverse correlations between QMUS, sEIM, and hEIM parameters and measures of knee extensor strength. Moderate to strong correlations (0.57–0.81) were noted between investigational measures and DEXA-measured fat mass. Conclusions: QMUS, sEIM and hEIM were highly reliable in a controlled, same-day testing protocol. Multiple correlations with measures of strength and body composition were noted for each method. Point-of-care technologies may provide an alternative means of measuring health.