d rhon, s de la motte, j fraser, t greenlee, b hando, j molloy, d teyhen, j tiede, j van wyngaarden, r westrick, g bullock

Musculoskeletal injuries enact a substantial burden in military settings, incurring high costs, long-term disability, and impacting military readiness. This has led to a prioritization of injury prevention programs. Understanding the challenges faced by those trying to implement these programs could help standardize and better inform future efforts. The purpose was to capture perceptions of barriers and facilitators to implementation of injury prevention programs in the US Armed Forces.

A cross-sectional survey with open-ended questions was circulated to relevant stakeholders; key themes were derived using conceptual content analysis. Four questions were asked concerning injury prevention programs: 1) barriers, 2) facilitators, 3) how can leadership best support, and 4) how can subject matter experts best collaborate to make these programs successful?

The survey reached at least 300 individuals working with the armed services worldwide; 91 completed the survey. The mean (SD) time working with military service members was 11.5 (8.2) years; 93 % worked with active-duty service members, 71.4 % were licensed healthcare providers, and 55 % worked in settings with established injury prevention programs. Only 45.2 % of participants believed an appropriate, clear way to measure program success currently exists. Nearly 85 % believed that lacking standardization of definitions and metrics hinders program assessment. Wide variability existed in opinions regarding who should be primarily responsible for promoting/supporting injury prevention efforts. Key themes included resources as both a facilitator (when present) and barrier (when absent), organizational culture, and leadership support. Leadership can best help by prioritizing the programs and valuing the programming through modeling the desired behavior. Program staff can collaborate by focusing on enabling change, integrating into organizational/unit culture and collaborating with leaders to change policy.

Daniel I. Rhon, Sarah J. de la Motte, John J. Fraser, Tina A. Greenlee, Benjamin R. Hando, Joseph M. Molloy, Deydre S. Teyhen, Jeffrey M. Tiede, Joshua J. Van Wyngaarden, Richard B. Westrick, Garrett S. Bullock. Perceived barriers and facilitators to implementation of injury prevention programs in the military: feedback from inside the trenches, Injury. 2024. 112029. ISSN 0020-1383, doi.org/10.1016/j.injury.2024.112029.

b hando, v pav, b isaacson, c colahan, w funk, x yuan

The U.S. Military Health System (MHS) transitioned to the ICD-10-CM coding scheme in October 2015 and began the phased rollout of a new electronic health record system, MHS GENESIS, in October 2017. Both changes have the potential to affect the observed prevalence and health care utilization associated with musculoskeletal injuries (MSKIs) in service members. The purpose of this article was to (1) determine the effect of the ICD-10-CM transition on the observed prevalence of select MSKI conditions and (2) describe MSKI-related health care utilization in four MTFs during the adoption of MHS GENESIS.

Ben Hando, Veronika Pav, Brad Isaacson, Courtney Colahan, Wendy Funk, Xiaoning Yuan, Musculoskeletal Injury Surveillance in the U.S. Military: Analysis of the ICD-10-CM Transition and Descriptive Report of Health Care Utilization at Four Sites Adopting MHS GENESIS, Military Medicine, Volume 189, Issue Supplement_4, November/December 2024, Pages 78–86, https://doi.org/10.1093/milmed/usad462

v pav, x yuan, b isaacson, w funk, b hando

Musculoskeletal injuries (MSKIs) represent the most common, costly, and impactful medical conditions affecting active duty service members (ADSMs) of the United States Armed Forces. Inconsistent, variable MSKI surveillance methods and often incompletely described criteria for cohort selection, injuries, incidence, and prevalence have limited efforts to observe longitudinal trends, identify gaps in care, or highlight specific military branches or sites that could benefit from enhanced MSKI intervention protocols. The purpose of this manuscript is to present a comprehensive, well-documented, and reproducible framework for capturing and categorizing MSKI burden, healthcare utilization, and private sector costs for ADSMs across a 12-year period spanning the International Classification of Diseases, 10th Revision, Clinical Modification transition.

Veronika Pav, Xiaoning Yuan, Brad Isaacson, Wendy Funk, Ben Hando, Capturing and Categorizing the Burden of Musculoskeletal Injuries in U.S. Active Duty Service Members: A Comprehensive Methodology, Military Medicine, Volume 189, Issue Supplement_4, November/December 2024, Pages 70–77, https://doi.org/10.1093/milmed/usae245

b isaacson, b hando, p pav, l wagner, c colahan, p pasquina, x yuan

Lower Extremity musculoskeletal injuries (LE MSKIs) represent a significant portion of overuse injuries in active duty service members (ADSMs). However, variations in study methods and research gaps related to LE MSKIs have prevented Department of Defense (DoD) leaders from assessing the burden of these conditions. The purpose of this study was to report the incidence, prevalence, and types of LE MSKIs sustained by ADSMs across four branches of service and describe associated health care utilization and private sector costs.

Brad Isaacson, Ben Hando, Veronika Pav, Linzie Wagner, Courtney Colahan, Paul Pasquina, Xiaoning Yuan, Lower Extremity Musculoskeletal Injuries in United States Active Duty Service Members: Prevalence/Incidence, Health Care Utilization, and Cost Analysis Spanning Fiscal Years 2016–2021, Military Medicine, Volume 189, Issue Supplement_4, November/December 2024, Pages 56–69, https://doi.org/10.1093/milmed/usae046

x yuan, e stewart, c colahan, p pasquina, b isaacson, v pav

Low back pain and musculoskeletal injuries (MSKIs) of the Spine are the most common reason for U.S. active duty service members (ADSMs) to seek medical care. The purposes of this descriptive study were to report the prevalence/incidence, health care utilization, and health care costs attributable to Spine (thoracic, lumbar, sacral, and pelvic) MSKIs across the four major branches of service from Fiscal Years (FY) 2016 to 2021.

Xiaoning Yuan, Emma Stewart, Courtney Colahan, Paul Pasquina, Brad Isaacson, Veronika Pav, Ben Hando, Musculoskeletal Spine Injuries in U.S. Active Duty Service Members: Prevalence/Incidence, Healthcare Utilization, and Cost Analysis Spanning Fiscal Years 2016–2021, Military Medicine, Volume 189, Issue Supplement_4, November/December 2024, Pages 45–55, https://doi.org/10.1093/milmed/usae248

b isaacson, b hando, v pav, l wagner, c colahan, p pasquina, x yuan

Upper Extremity musculoskeletal injuries (UE MSKIs) represent a major threat to the overall health and readiness of U.S. active duty service members (U.S. ADSMs). However, a lack of prior research and inconsistent study and surveillance methodology has limited Department of Defense (DoD) leaders from assessing and addressing the burden of these conditions. The purpose of this study was to report the incidence, prevalence, and types of UE MSKIs sustained by ADSMs across four branches of service and describe associated health care utilization and private sector costs.

Brad Isaacson, Ben Hando, Veronika Pav, Linzie Wagner, Courtney Colahan, Paul Pasquina, Xiaoning Yuan, Upper Extremity Musculoskeletal Injuries in United States Active Duty Service Members: Prevalence/Incidence, Health Care Utilization, and Cost Analysis Spanning Fiscal Years 2016–2021, Military Medicine, Volume 189, Issue Supplement_4, November/December 2024, Pages 34–44, https://doi.org/10.1093/milmed/usae047

x yaun, e stewart, c colahan, p pasquina, b isaacson, v pav, b hando

Active duty service members (ADSMs) of the U.S. Armed Forces are uniquely at risk for musculoskeletal injuries (MSKIs) of the Head/Neck region, including the eye and face, from training with head gear, donning Kevlar, operating aircraft, and maintaining sitting or standing postures for prolonged durations. The purposes of this descriptive study were to report the prevalence/incidence, health care utilization, and health care costs attributable to Head/Neck MSKIs across the Services from fiscal years (FYs) 2016 to 2021.

Xiaoning Yuan, Emma Stewart, Courtney Colahan, Paul Pasquina, Brad Isaacson, Veronika Pav, Ben Hando, Musculoskeletal Head and Neck Injuries in U.S. Active Duty Service Members: Prevalence/Incidence, Health Care Utilization, and Cost Analysis Spanning Fiscal Years 2016–2021, Military Medicine, Volume 189, Issue Supplement_4, November/December 2024, Pages 22–33, https://doi.org/10.1093/milmed/usae045

c colahan, v pav, x yuan, b isaacson, l wagner, b hando

Musculoskeletal injuries (MSKIs) represent the most substantial and enduring threat to U.S. military readiness. Previous studies have focused on narrow surveillance periods, single branches of service, and used variable approaches for MSKI identification and classification. Therefore, the goals of this retrospective population study were to report the incidence, prevalence, and types of MSKIs sustained by active duty service members (ADSMs) across four Services in direct care (DC) and private sector care (PC) settings over fiscal years (FYs) 2010–2021, and to quantify and describe associated health care utilization and PC costs over the same period.

Courtney Colahan, Veronika Pav, Xiaoning Yuan, Brad Isaacson, Linzie Wagner, Ben Hando, Musculoskeletal Injuries in Female U.S. Active Duty Service Members: Prevalence/Incidence, Health Care Utilization, and Cost Analysis Spanning Fiscal Years 2016–2021, Military Medicine, Volume 189, Issue Supplement_4, November/December 2024, Pages 10–21, https://doi.org/10.1093/milmed/usae308

V Pav, x yuan, b isaacson, c colahan, b hando

Musculoskeletal injuries (MSKIs) represent the most substantial and enduring threat to U.S. military readiness. Previous studies have focused on narrow surveillance periods, single branches of service, and used variable approaches for MSKI identification and classification. Therefore, the goals of this retrospective population study were to report the incidence, prevalence, and types of MSKIs sustained by active duty service members (ADSMs) across four Services in direct care (DC) and private sector care (PC) settings over fiscal years (FYs) 2010–2021, and to quantify and describe associated health care utilization and PC costs over the same period.

Veronika Pav, Xiaoning Yuan, Brad Isaacson, Courtney Colahan, Ben Hando, Burden of Musculoskeletal Injuries in U.S. Active Duty Service Members: A 12-Year Study Spanning Fiscal Years 2010–2021, Military Medicine, Volume 189, Issue Supplement_4, November/December 2024, Pages 1–9, https://doi.org/10.1093/milmed/usae357

Galvin J, Milam r, patterson b, mepola j, buckwalter j, wolf b, say f, free k, yohannes e

Abstract accepted for platform presentation at the 2024 Society of Military Orthopaedic Surgeons (SOMOS) Annual Meeting

The incremental biological changes in the synovial microenvironment of the shoulder in acute and chronic instability that may contribute to joint degeneration are poorly understood. Proteomic analysis of synovial fluid in patients with shoulder instability may improve our understanding of proteins that are shed into shoulder synovial fluid after an injury.

Proteomic analysis enriched our understanding of proteins that were secreted into shoulder synovial fluid of patients with shoulder instability. The identification of POSTN, a proinflammatory catabolic protein involved with tissue remodeling and repair, as a significant target in anterior shoulder instability is a novel finding. Therefore, further study is warranted to determine the role that POSTN may play in the progression of bone loss and posttraumatic osteoarthritis.

e Florkiewicz, k east, m crowell, a weart, g freisinger, d goss

In-clinic gait retraining has been effective in modifying suspected biomechanical risk factors for running injury, but its feasibility is often limited by multiple clinic visits. This randomized clinical trial investigated the effects of a telehealth-based gait retraining intervention on running biomechanics, pain, and function in previously injured runners.

Twenty-three participants recovering from lower extremity injuries were randomized to a control or intervention group. The intervention group completed 4 to 6 telehealth gait retraining sessions over 8 to 10 weeks, consisting of visual and verbal cues to transition to a non-rearfoot strike pattern and increase step rate. The control group received standard physical therapy. Biomechanics, pain, and function were assessed pre- and post-intervention using a 2 × 2 mixed model analysis of variance.

Half of the participants (55 %) in the intervention group successfully transitioned to a non-rearfoot strike pattern. No significant differences were observed between groups in step rate, biomechanics, or function. A significant group-by-time interaction for pain was observed (F = 10.55, P = 0.004), with the intervention group reporting greater reductions in pain compared to the control group (mean difference 2.52, 95 % CI 0.91 to 4.12).

Erin M. Florkiewicz, Kyle H. East, Michael S. Crowell, Amy N. Weart, Gregory M. Freisinger, Donald L. Goss. The effects of telehealth running gait retraining on biomechanics, pain, and function in patients with lower extremity injuries: A randomized clinical trial. Clinical Biomechanics, 2024. 106381, ISSN 0268-0033. https://doi.org/10.1016/j.clinbiomech.2024.106381.

m Crowell, e florkiewicz, j morris, j mason, w pitt, t benedict, k cameron, d goss

Abstract accepted for platform presentation at the 2025 American Physical Therapy Association Combined Sections Meeting- Houston, TX

Purpose/hypothesis: Shoulder instability is common in active young athletes and military personnel, often requiring shoulder stabilization surgery. Acute post-operative pain is usually managed with opioid pain medications, which have adverse effects that reduce military readiness. Battlefield Acupuncture (BFA) has demonstrated promise as a non-pharmaceutical intervention for acute post-operative pain. The purpose of this randomized clinical trial was to assess the effectiveness of BFA on post-surgical pain and opioid medication usage.

i gaunaurd, m sumner, p pasquina, a symsack, j haynes, c bennett, r gailey

Abstract accepted for platform presentation at the 2025 American Physical Therapy Association Combined Sections Meeting- Houston, TX

Purpose/hypothesis: Veterans with lower limb loss (LLL) are a complex population with their own unique challenges with rehabilitation but share many commonalities with the general population. This case series highlights two examples of a physical therapist and patients with LLL who participated in the Mobile Device Outcomes Based Rehabilitation Program at the Bruce W. Carter VA Medical Center, Miami, FL using a novel mobile sensor system and application called Rehabilitative Lower Limb Orthopaedic Assistive Device (ReLOAD) to augment rehabilitation.

i gaunaurd, p pasquina, a symsack, m sumner, j haynes, t fields, a munoz-boyle, l prasso, christina sole-plasa, j stevens, c bennett, b applegate, b isaacson, r gailey

Abstract accepted for platform presentation at the 2025 American Physical Therapy Association Combined Sections Meeting- Houston, TX

Purpose/hypothesis: Supported by the DoD/VA Joint Incentive Fund, Mobile Device Outcomes-based Rehabilitation Program (MDORP) utilizes mobile technology, called Rehabilitative Lower Limb Orthopedic Assistive Device (RELOAD) to enhance the rehabilitation of Services Members (SMs) and Veterans with lower limb loss (LLL). The ReLOAD system assesses walking quality, provides auditory feedback to correct gait deviations, and recommends patient-speci c exercises that target their impaired function and limitations. The purpose of this study is to examine the use of the RELOAD system in the clinical practice of Physical Therapists (PTs) to optimize assessment and care of SMs and Veterans with LLL.

A Symsack, i gaunaurd, j haynes, m sumner, c bennett, b isaacson, p pasquina, r gailey

Abstract accepted for platform presentation at the 2025 American Physical Therapy Association Combined Sections Meeting- Houston, TX

Purpose/hypothesis: The home-based exercise program (HEP) for patients in rehabilitation following lower limb loss (LLL) is an integral part of the continuity of care outside the clinic for the maintenance and improvement of strength, mobility, and functional goals. However, clinical evidence shows that patients have varying degrees of exercise adherence to HEPs. Evidence-based exercise prescription to improve HEP adherence has suggested dosing of 20 minutes daily, minimum of three times per week or the completion of two-thirds of the prescribed exercise routine. The purpose of this study is to determine patient adherence to their HEP among SMS and Veterans with LLL using the Rehabilitative Lower Limb Orthopaedic Assistive Device (ReLOAD).

A Symsack, i gaunaurd, j haynes, m sumner, c bennett, b isaacson, p pasquina, r gailey

Abstract accepted for platform presentation at the 2025 American Physical Therapy Association Combined Sections Meeting- Houston, TX

Purpose/hypothesis: The rehabilitation for Service Members (SMS) and Veterans with lower limb loss (LLL) can involve months of prosthetic training and targeted exercises intended to improve gait quality and functional mobility. During this time, Physical Therapists (PTS) prescribe home exercise programs (HEP) as part of the plan of care, which serve to augment treatment and improve or maintain patient function while outside the clinic. The purpose of this study is to identify the targeted exercise prescription trends following initial evaluation (eval) among PTS who are participating in the Mobile Device Outcomes Based Rehabilitation Program (MDORP) for SMS and Veterans with LLL.

t velasco, n reilly, c hulsopple, k roberts, s wise, d goss, j leggit

Abstract accepted for poster presentation at the 2025 American Physical Therapy Association Combined Sections Meeting- Houston, TX

Background and Purpose: Chronic exertional compartment syndrome (CECS) is a debilitating condition for soldiers marked by lower-limb pain, paresthesia, and weakness1,2. While the gold standard treatment has long been fasciotomy, anecdotal data shows mixed results and limited predictive success following the procedure3,4. Alternative approaches to treating CECS have included pharmaceutical interventions (i.e., Botulinum toxin, BoTN-A)5,6 and structured gait retraining to ameliorate movement patterns7. However, the incorporation of a combination of non-surgical interventions for CECS has not been extensively studied in military personnel. Thus, the purpose of this case study was to evaluate a multimodal combination of treatment approaches for CECS in a soldier to identify an efficacious way to address running parameters and reduce pain to improve function.  

Case Description: A 27-year old female Soldier diagnosed with bilateral anterior and lateral lower leg CECS was recruited to participate in a larger cohort study.  She received saline injections and supervised gait retraining, including strengthening and flexibility exercises. The participant had their running gait assessed using pressure-sensitive insoles (LoadSol, Novel USA, St. Paul, MN) at the initial treatment, after 8-weeks, 3-months, and 6-months. Time points of 12- and 24-months running assessments were not collected as she moved out of network. Between the 3- and 6-months visit, the participant elected to cross-over treatment therapies and received BoTN-A. Clinical metrics included numeric pain rating scale (NPRS), the Single Assessment Numerical Evaluation (SANE) and University of Wisconsin Running Index (UWRI), as well as the Global Rating of Change scale (GROC). These metrics were obtained up to 24 months post initial injection.

Outcomes: From baseline to the 3-month mark, the participant showed improvement on clinical metrics including a 90.9% increase in UWRI and a GROC of 5. These metrics are accompanied by a 22.5% increase in cadence and a 10.2% decrease in peak ground reaction force (GRF). Notably, the patient still reported an NPRS of 5/10 (7/10 baseline) with running at 3-months. Following the BoTN-A injections, the participant at 6-months displayed a 17.9% decrease in average vertical loading rate (AVLR) and a 2.0% decrease in peak GRF. Clinically, she displayed improvements in UWRI of 47.6%, SANE of 20.0%, and a GROC of 6, along with NPRS of 0/10 with running. At 12-months, NPRS remained at 0/10 with running, but UWRI and GROC scores slightly decreased, likely from her reported knee injury. At 24-months, the participant reported no pain with running and perfect SANE, UWRI, and GROC scores.

Discussion: This case study demonstrates gait retraining can be beneficial for improving pain and function in soldiers with lower leg CECS.  The addition of BoTN-A injections in this case suggests it may be a useful supplemental modality in rehabilitation for long-term benefits for CECS patients. However, further research is needed to confirm these findings in a larger population.

m smith, x yuan, j smith, j banks deal jr, g nanos, s tintle, d reece, m miller

Abstract awarded the Jamie Dianne Bulken-Hoover Memorial- Best Hand Paper at The Society of Military Orthopedic Surgeons Annual Meeting in Nashville, TN- December 2024

Carpal tunnel release (CTR) using a mini-open (mOCTR) or endoscopic approach is the current standard of care (SOC) in the Military Health System (MHS) for management of refractory carpal tunnel syndrome (CTS), the most common peripheral entrapment neuropathy. CTR techniques have evolved over time to reduce iatrogenic tissue trauma and post-operative pain, promoting quicker recovery and improved outcomes. CTR using Ultrasound Guidance (CTR-US) is a promising treatment option under study for military beneficiaries with CTS in a trial comparing outcomes of CTR-US and mOCTR.

This single-site pragmatic randomized controlled feasibility trial at Walter Reed National Military Medical Center (WRNMMC) was approved by the Institutional Review Board (WRNMMC-2020-0278). Military beneficiaries (18-89 years) with clinical, electrodiagnostic, and sonographic findings consistent with CTS were enrolled. Exclusion criteria included prior wrist surgery, median nerve trauma, or sonographic findings precluding safe and effective CTR-US.

Participants were randomized to receive either CTR-US by board-certified Physical Medicine and Rehabilitation physicians with advanced training in ultrasound-guided procedures in a clinic procedure room with local anesthesia, or mOCTR by board-certified Orthopedic Hand Surgeons in a clinic procedure room with local anesthesia or operating room (OR) with moderate sedation. CTR-US was performed under continuous ultrasound guidance with a device featuring inflatable balloons to create space within the carpal tunnel and a retractable blade that releases the transverse carpal ligament in a retrograde manner.

Demographics and patient-reported outcome measures (PROMs) were collected at baseline. Follow-up PROMs were collected at 1, 2, 3, 4, 6 weeks, 3, 6, 12, and 24 months post-procedure. The primary outcome was the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) at 1 month. Additional outcomes included Boston Carpal Tunnel Questionnaire – Symptom Severity Scale (BCTQ-SS), Numerical Pain Rating Scale (NPRS), Global Assessment of Satisfaction, Global Rating of Change (GROC), modified 2-item CTS Palmar Pain Scale; grip and pinch strength (3 and 12 months); procedure time and incision length; and adverse events. Descriptive analyses reported central tendencies in terms of location (e.g., mean) and scale (e.g., standard deviation) for all study variables. Inferential analyses included two-sample Welch’s T-tests (α = 0.01) for procedural data and complete-case, intention-to-treat, generalized additive models incorporating multi-level structures through patient-level random effects for all other outcomes. No confidence interval (α = 0.05) overlaps on generalized additive models indicated statistical significance.

CTS is the most common peripheral entrapment neuropathy, impacting the health of military beneficiaries. CTS treatment barriers within the MHS include limited access to subspecialty care, lack of resources, and OR procedural costs. Preliminary data from this trial suggest that CTR-US can be performed within a clinic environment by non-operative physicians with advanced training, resulting in decreased post-procedural incisional pain and non-inferior outcomes compared to mOCTR approach out to 2 years. Outcomes of this WRNMMC trial can facilitate expansion of available CTS management options within the MHS, improving access to care and operational readiness.

martin c, nocera m, mercer j, marshall s, davi s, curtin j, cameron k

Mobile applications (apps) may be beneficial to promote self-management strategies to mitigate the risk of developing post-traumatic osteoarthritis in military members following a traumatic knee injury. This study investigated the efficacy of a mobile app in facilitating behavior modification to improve function and symptomology among military members.

This is a preliminary pre and post hoc analysis of a randomized control trial. The MARX scale, Intermittent and Constant Osteoarthritis Pain (ICOAP) questionnaire, and the Knee Injury and Osteoarthritic Outcome Score Readiness to Manage Osteoarthritis Questionnaire were completed at baseline, 6-week, 6-month, and 12-month follow-up. Participants in the treatment arm completed the System Usability Scale. Data were analyzed using descriptive statistics, the Wilcoxon sum of ranks test, the Wilcoxon signed-rank test, and Cohen’s d effect size.

A total of 28 participants were included. Between-group differences for baseline and 6-week follow-up were significantly improved in the injured knee ICOAP constant pain score for the treatment group (treatment: −4.2 ± 12, 95% CI: −11.5, 3.1; control: 5.5 ± 9.9, 95% CI: 0.9, 10.1; P = .035, effect size = 0.905). Within-group differences for baseline and 6-week follow-up demonstrated a significant decline in the injured knee ICOAP constant pain score among the control group (signed-rank: 16.0, P = .031, Cohen’s d = 0.339). No other significant differences were observed. A good System Usability Scale score for usability was found (76.6 ± 8.8).

These results indicate that the mobile app is easy to use and may contribute to improved constant pain symptomology for patients at risk for post-traumatic osteoarthritis.

Chelsea Leonard Martin, Maryalice Nocera, Jeremy Mercer, Stephen W Marshall, Steven M Davi, Jessica J Curtin, Kenneth L Cameron, Efficacy of a Novel Telehealth Application in Health Behavior Modification and Symptomology in Military Service Members at Risk for Post-traumatic Osteoarthritis, Military Medicine, 2023;, usad435, https://doi.org/10.1093/milmed/usad435

cheema n, ghag n, wise e, pham l, nazarian a, fuchs c, tam j, anderson r

Abstract accepted for poster presentation at the 2024 Military Health System Research Symposium

Fatigue is defined by the reduction of a muscle’s strength and performance during exercise, and it is affected by different parts of the motor pathway controlling muscle contractions. Fatigue limits performance and unless allowed to recover, continuous activity will result in musculoskeletal injuries that are commonly observed in military personnel. Light therapy has been shown to have several beneficial physiologic effects in a wide range of tissues. The musculoskeletal system can be irradiated with wavelengths in red and near infrared (NIR) regions which penetrate deep into the body. Recent studies are suggesting that photobiomodulation therapy (PBMT) can reduce pain, inflammation and enhance physical performance. However, the mechanism(s) of cellular responses by PBM in muscle is not clearly understood. There is no standardization in parameters for PBMT, with researchers and clinicians using a wide range of wavelengths, fluences, etc. Therefore, the goal of this study is to improve our understanding of the mechanism(s) of action of PBM effects on the musculoskeletal system, ultimately to inform the choice of clinical treatment parameters. We investigate the application of 830 nm and its effect on fatigue induced in intense exercise in mice. We performed a treadmill fatigue assay on mice and collected muscle tissue for histological and biochemical analysis. We observed that PBMT mice ran twice as long. Electron microscopy of fatigued muscle had some evidence of cellular stress where mitochondrial structure is altered whereas 830 nm treated muscle had a preservation of mitochondrial morphology. RNAseq data from fatigue muscle suggests that treated mice have an upregulation of genes involved in tissue remodeling, specifically cytoskeletal and vasculature markers. During muscle regeneration, mechanoreceptors, known as muscle spindle fibers form after innervation by the motor neuron. We saw increased number of muscle spindle fibers, which stimulate muscle contraction in response to stretch. Other signs of muscle regeneration, also observed in our treated muscle, are myoblast fusion and central localization of the myonucleus. In conclusion, our study suggests that 830 nm may have altered the muscle by activating regenerative genes that protect the muscle from cellular stress from intense exercise.