Sports Medicine Clinic Research Articles

Low energy availability surrogates are associated with Relative Energy Deficiency in Sport outcomes in male athletes

ObjectivesTo determine the association between surrogates of low energy availability (EA) and proposed health and performance outcomes of Relative Energy Deficiency in Sport (REDs) in a clinical sample of adolescent...

Factors that Influence Recovery From Concussion in Young Children and Preadolescents

Objective: To examine differences in the presentation and management of concussion in younger children (aged 4–8 years) versus preadolescents (9–12 years) and identify factors that influence recovery time. Design: Retrospective analysis of prospectively collected data. Setting: Pediatric sports medicine and orthopedics clinic. Patients: Three hundred seventy-five patients aged 4 to 12 years diagnosed with concussion between 2020 and 2022. Independent Variables: Age, gender, race/ethnicity, mechanism of injury (sport vs nonsport related), neurodevelopmental or psychiatric diagnosis, concussion history, Post-Concussion Symptom Scale (PCSS) score, and Vestibular Ocular Motor Screening (VOMS) overall change scores. Main Outcome Measures: Days since injury (DSI) to initial visit, total number of visits, recovery time (days). Results: Groups significantly differed in DSI (P = 0.01) and overall VOMS change score (P = 0.03). No differences were observed between groups on total number of visits or recovery time. Patients with fewer DSI [odds ratio (OR) = 1.15], less change in overall VOMS score (OR = 1.02), lower PCSS scores (OR = 1.02), and who were injured in sport were less likely to experience a protracted recovery. Conclusions: Younger children with concussion may be appropriately treated with a similar approach to preadolescent patients despite greater DSI and differences in VOMS change scores, without sacrificing overall recovery time. Consistent with research in older cohorts, protracted recovery was seen in nonsport patients, and patients seen sooner at a specialty concussion clinic were less likely to experience a protracted recovery, endorsed lower PCSS scores, and had lower overall VOMS change scores. Further research is needed to solidify a child-specific paradigm to concussion management.

Use of Telemedicine in a Sports Medicine Clinic: An Investigation of Patient Satisfaction

Objective: Compare patient satisfaction between telemedicine and in-office visits and between providers post-operatively in an orthopedics setting with athletic trainers and physicians. Design: Cross-sectional study Methods: Patients from a Sports Medicine Clinic that received an orthopedic surgical intervention from March 2020-September 2021, and engaged in telemedicine, or an in-office visit post-operatively. Provider type included full-time athletic trainers, resident athletic trainers, physician (MD) resident/fellows, and float athletic trainers. Press-Ganey Patient Experience Surveys were collected at the time of follow up visit, with focus on items, “likelihood to recommend” and “how well staff worked together.” Results: There was a total of 255 patients (age=50±17 years). Providers included the attending physician with full-time athletic trainers (n=134, 52.3%), resident athletic trainers (n=77, 30.1%), MD residents/fellows (n=38, 14.8%), or float athletic trainers (n=6, 2.3%). No significant difference was found with patient satisfaction between in-office (n=175, 68.4%), or telemedicine visits (n=80, 31.3%), (p>.44). Patients were more satisfied with care provided by the full-time athletic trainers compared to MD residents/fellows (p.18). Conclusions: This study demonstrates no significant differences with patient satisfaction between in-office or telemedicine visits. Patients seeing full-time athletic trainers had the highest patient satisfaction, demonstrating the capability of athletic trainers to effectively use telemedicine in a physician practice.

How Athletic Swiss Patients Experience Their Return to Sports After Anterior Cruciate Ligament Reconstruction: Results from a Retrospective Self-Assessment.

Anterior cruciate ligament (ACL) ruptures are frequent injuries, especially in athletes. Return to sports after reconstruction of the ligament is a frequently debated topic and of high relevance for these patients. It is mostly achieved at 9-12 months post-surgery. However, the risk of subsequent knee injuries is high and psychological factors play an important role in the process and success of returning to sports. Little is known about patients' perception of their journey returning to sports. This study aims to fill the gap. The study aimed to include patients treated surgically for an ACL injury over 5 years at a specialized sports-medicine clinic. Patients were surveyed on the impact of the injury on their lives, their return to sports experience, and medical history. In total, 100 (of 474) patients aged 35.9 years responded. Within 5 years, 19% experienced a reoperation and 23% a new knee injury. Overall, 83% of patients returned to their main sport, 72% reached their pre-injury level. However, 45% reported at least one distinct or severe consequence of their ACL injury. The ability to return to sports had more impact on the perception of the course of treatment than the experience of new injuries or surgery. The rate of successful return to sports was comparable to previous reports despite a higher average age in this cohort. A successful return to sports seems to be a major determinant for the perception of impact from the injury and may be more important than the avoidance of repeat trauma.

Injury Patterns in Fencing Athletes - A Retrospective Review.

Fencing is a unique and increasingly popular sport, but limited data exist regarding related injuries. To examine the types of injuries incurred by fencing athletes, and to analyze associations between age, sex, and hand dominance with type and location of injury. Cross-sectional. Retrospective chart reviews were performed to evaluate fencing related injuries in athletes evaluated in the sports medicine and orthopedic clinics of a large teaching hospital. One hundred and eighty-six patients (98 male, 88 female) were included. Average age at time of injury was 14.6 years (range 9 - 32 years). 73% of injuries involved the lower extremity, 16% involved the upper extremity and 10% affected the back. In the lower extremity, the knee (49%), ankle (16%) and hip (11%) were most commonly affected. 80% of injuries were treated with physical therapy. Only 5% required surgical intervention. Injuries of both upper and lower extremities were more commonly seen on the athlete's dominant side, and the majority of injuries (77%) occurred in athletes 13 years or older. The majority of injuries in these fencing athletes affected the lower extremity, most commonly the knee. Extensor mechanism dysfunction, primarily patellofemoral pain, was the most common diagnosis. Hand dominance, patient age, and patient sex did affect different injury characteristics. 2b.

Platform Design for Optical Screening and Conditioning for Injury Resilience.

Musculoskeletal injuries (MSKIs) among active duty soldiers result in more than 10 million limited duty days each year and account for more than 70% of the medically nondeployable population. Overuse injuries in lower limbs from running, foot marching long distances with heavy loads, and lifting heavy objects are the most common types of injuries in the military. Physical training and rehabilitation exercises for greater resiliency through aerobic, muscle strength, endurance, and agility conditioning programs can prevent or reduce the effects of MSKIs if Soldiers adhere to proper biomechanics and training techniques. We are introducing a three-dimensional (3D) camera-based platform for Optical Screening and Conditioning for Injury Resilience (OSCIR) that is designed to identify and correct high-risk movement patterns based on quantifiable biomechanical measurements in clinical or field settings. Our goal is to improve resilience to MSKI by offering greater access to quality of movement skills in warfighters through an autonomous device that can be used in Sports Medicine and Reconditioning Team (SMART) clinics and High-Intensity Tactical Training (HITT) sites. OSCIR fuses four pairs of Kinect Azure cameras into a concise footprint to achieve suitable sampling rates and an unobstructed field of view for accurate dynamic movement tracking using a custom point cloud solution. We designed a unique multistage 3D joint tracking algorithm architecture to methodically isolate the human body point cloud from the background, identify individual limb segments, and perform iterative joint optimization at the global and local joint levels. We evaluated the feasibility of our prototype system among N = 12 control participants (6 M/6 F; 21-37 years) in compliance with the Western Institutional Review Board (Tracking #20225920, approved on November 4, 2022). Five task-specific MSKI outcome metrics identified by end-user physical therapists and athletic trainers as indicators for movement quality were assessed across 7 lower-extremity exercises derived from standardized MSK assessment/conditioning batteries used in the military. Data were recorded concurrently by OSCIR and a reference standard Vicon motion capture system for validating system accuracy. Task-specific MSKI indicators for knee flexion and hip flexion range of motion achieved an average error of 4.05 ± 2.34°, while 3D position-based postural outcomes of left-right foot distance, left-right hand distance, and step length obtained mean absolute errors of 2.58 ± 2.30 cm. Results support the feasibility of our system in achieving outcomes that are comparable to currently accepted laboratory standards. Our study describes the integration process for a 3D camera-based clinical system for MSKI conditioning and rehabilitation. The impact of our system will enable key stakeholders in the military to manage MSKIs in warfighters by automating key assessment and rehabilitation test batteries; making tests more readily accessible, and interpretations more accurate by providing objective biomechanical measures. OSCIR is undergoing turn-key design features to serve as a screening tool for warfighters to readily assess susceptibility to MSKI or as a training platform to help guide exercise techniques to achieve resiliency against future injuries.

The Antigravity Treadmill as a Postoperative and Injury Rehabilitation Tool: Reduction in Contact Forces and Muscle Activity With Reduced Weight Running.

To investigate the effects of reduced weight running on the antigravity (AG) treadmill on maintenance of normal muscle activation and reduction of plantar forces in healthy subjects. Descriptive laboratory study. Clinical sports medicine center. Twenty healthy subjects (10 male and 10 female) aged 18 to 29 years. Subjects running at 6.5 miles per hour on a standard treadmill and on the AG treadmill at 100%, 90%, 80%, 70%, 60%, and 50% of bodyweight levels. Dynamic plantar loading data were recorded using pressure insoles. Surface electromyography electrodes with imbedded accelerometers were used to estimate timing and magnitude of muscle activity, stride length, and cadence. There was a significant, sequential reduction in peak pressure, maximum force, and force time integral (FTI) with decreasing bodyweight. A 50% bodyweight reduction resulted in a 51% reduction in maximum force and a 59% reduction in FTI in the heel, as compared with 19% to 28% at the metatarsal heads. There was reduced contact area in the heel and midfoot at and below 70% BW. Lower limb muscle activity decreases with reduced bodyweight while maintain normal muscle recruitment timing. The AG treadmill provides a reduction in loading forces while maintaining normal muscle recruitment patterns. Decreased BW running preferentially unloads the hindfoot. The AG treadmill can be an effective rehabilitation tool following foot or ankle injury and may prove superior to other limited weight-bearing methods.

New-Onset Gaze Palsy in a Sports-Related Concussion.

Concussions are a common injury in pediatric sports medicine clinics. Occasionally, a patient presenting for concussion will demonstrate abnormal neurologic findings, but in this case, a gaze palsy was witnessed during the initial 2 weeks following closed head injury with subsequent complete resolution of symptoms. There are limited available studies or case reports demonstrating this atypical presentation; thus, this case study aims to provide sports medicine physicians a reference for future similar atypical presentations.

Shared Decision-Making About Returning to Sport After Recovery From Pediatric Concussion: Clinician Perspectives.

Describe how sports medicine clinicians support decision making about sport participation after concussion recovery with adolescent patients and their parents. Specific areas of inquiry related to how clinicians framed the decision, what factors they considered in how they approached the decision process, and how they navigated discordance within families. Qualitative study. Tertiary care sports medicine clinics at 4 children's hospitals in the United States. Individual interviews were conducted with 17 clinicians practicing in sports medicine settings. N/A. Semi-structured interviews explored clinician approaches to supporting decision making, with the question guide informed by components of the Ottawa Decision Support Framework. Clinicians routinely incorporated aspects of shared decision making (SDM) into their conversations with families. This included ensuring all parties were informed about risk and aligned behind a shared value of adolescent well-being. Mediation strategies were used to manage discordance between adolescents and their parents, and between parents. These strategies aimed to facilitate a decision that was adolescent centered. When clinicians believed that there was a medical benefit to modifying the adolescent's sport participation practices, or when they did not believe the athlete was psychologically ready to return to the sport in which they were injured, they initiated conversations about alternative activities. In such situations, they used persuasive communication practices to encourage families to strongly consider this option. The strengths and strategies used by sports medicine clinicians in this study provide a foundation for guidance or intervention development aimed at supporting SDM after concussion with adolescents and their families.

Management of sports injury treatment and radiological data analysis based on enhanced MRI image retrieval using autoencoder-based deep learning

BackgroundThe retrieval of magnetic resonance imaging (MRI) data holds paramount importance in clinical settings and sports medicine due to the limitations of conventional methods, such as slow speed, low accuracy, and limited learning capabilities. Enhancing this retrieval process is critical for advancing sports injury diagnostics and treatment outcomes. Overcoming these challenges is vital for improving healthcare practices and sports medicine methodologies. MethodThis study investigates the utilization of autoencoders in deep learning to efficiently retrieve MRI data from databases for sports injury diagnosis and treatment, with a focus on the model's ability to be trained with a small amount of labeled data. This research aims to enhance the MRI data retrieval process by leveraging autoencoders, showcasing the potential of deep learning technologies in sports injury diagnostics without the necessity of extensive labeled datasets for training. ResultsFindings have showcased the remarkable benefits of this approach for MRI data retrieval tasks, achieving an average accuracy of 99.09%. This signifies the exceptional performance of the technique within this specific domain, demonstrating its effectiveness and reliability in extracting MRI data. ConclusionsThis innovative methodology can enhance the management of archival data and diagnostic capabilities of medical images in sports injury contexts, offering an efficient and dependable solution for MRI data retrieval. It not only facilitates rapid clinical diagnosis and sports medicine research but also proposes a convenient approach for medical image file management.

Adolescents With a High Burden of New-Onset Mood Symptoms After Sport-Related Concussion Benefit From Prescribed Aerobic Exercise, a Secondary Analysis of 2 Randomized Controlled Trials.

Approximately 20% of students with sport-related concussion (SRC) report new symptoms of anxiety and depression which may be associated with delayed recovery and increased risk for developing a mood disorder. Early prescribed aerobic exercise facilitates recovery in athletes with concussion-related exercise intolerance. We studied the effect of aerobic exercise treatment on new mood symptoms early after SRC. Exploratory secondary analysis of 2 randomized controlled trials (RCT). Sports medicine clinics associated with UB (Buffalo, NY), CHOP (Philadelphia, PA), and Boston Children's Hospital (Boston, MA). Male and female adolescents (aged 13-18 years) diagnosed with SRC (2-10 days since injury). Participants were randomized to individualized targeted heart rate aerobic exercise (n = 102) or to a placebo intervention designed to mimic relative rest (n = 96). Incidence of Persisting Post-Concussive Symptoms (PPCS, symptoms ≥28 days). First RCT recruited from 2016 to 2018 and the second from 2018 to 2020. Of 198 adolescents, 156 (79%) reported a low burden (mean 1.2 ± 1.65/24) while 42 (21%) reported a high burden (mean 9.74 ± 3.70/24) of emotional symptoms before randomization. Intervention hazard ratio for developing PPCS for low burden was 0.767 (95% CI, 0.546-1.079; P = 0.128; β = 0.085) and for high burden was 0.290 (95% CI, 0.123-0.683; P = 0.005; β = 0.732). High burden of mood symptoms early after injury increases risk for PPCS, but the sports medicine model of providing early targeted aerobic exercise treatment reduces it. Nonsports medicine clinicians who treat patients with a high burden of new mood symptoms after concussion should consider prescribing aerobic exercise treatment to reduce the risk of PPCS and a mood disorder.

The Utility of Musculoskeletal Ultrasound in Diagnosing Uncommon Talocrural Synovitis in an Amateur Weightlifting Athlete

The use of musculoskeletal ultrasound to assess sports-related injuries has been increasing worldwide. This case report focuses on an unusual form of synovitis of the talocrural joint in a 33-year-old male amateur weightlifter who presented to our sports medicine clinic with acute non-traumatic left ankle pain lasting for 2 days. He reported a recent change in his squatting technique and had no significant medical history other than a recent viral upper respiratory illness. Weight-bearing ankle X-rays were inconclusive, however, ultrasound evaluation revealed effusion in the talocrural joint upon assessment of the ankle’s anterior joint capsule. Additionally, the ultrasound examination helped rule out other common soft tissue ankle pathologies that can affect athletes. The athlete's symptoms resolved by day 5 with conservative measures, including weight bearing as tolerated, nonsteroidal anti-inflammatory drugs, and lymphatic drainage techniques. This report demonstrates the utility of musculoskeletal ultrasound in diagnosing an uncommon cause of ankle pain in athletes.

Understanding the Role of Nutrition in Musculoskeletal Healing: Assessing Patient and Physician Perceptions in an Urban Orthopaedic and Sports Medicine Clinic

Understanding the Role of Nutrition in Musculoskeletal Healing: Assessing Patient and Physician Perceptions in an Urban Orthopaedic and Sports Medicine Clinic

Development and implementation of an injury and illness surveillance system for team USA

BackgroundThe purpose of this report is to provide insight and details regarding the development and implementation of an injury and illness surveillance (IIS) system for the United States Olympic and Paralympic Committee (USOPC).MethodsThe development and deployment of the IIS employed a multiphase approach. First, researchers determined variables to include in the IIS using the recommendations from the 2020 IOC consensus statement for reporting sport epidemiological data. Second, the hosting and deployment platforms were comprehensively evaluated for their suitability, ease of use, flexibility, and backend data structure (for both capture and aggregation). Third, focus groups consisting of the Sports Medicine department leadership and clinicians piloted the IIS system and revisions were made based on their feedback. Pilot testing of the IIS and follow-up focus groups were then conducted among all departmental clinicians to solicit additional feedback and drive further revisions. Finally, the IIS system was piloted among providers working during the 2023 Pan American and Parapan American Games to refine the system for future Games. After reviewing all potential software platform options (electronic medical record [EMR] system, athlete management systems, secure data collection platforms), Qualtrics (Qualtrics, Provo, UT, USA) was selected to host the IIS system. This choice was made due to the inability of the EMR and athlete-management systems to make frequent updates, modify existing questions, and provide the necessary form logic for the variety of scenarios in which the IIS system would be deployed. Feedback from the department’s leadership and clinicians resulted in a number of changes, most notably being the ability to enter multiple diagnoses for a single injury event. Additionally, clinician feedback resulted in the creation of additional diagnostic codes not currently present in the OSIICS v14.0 diagnostic coding system, adding “non-sport” as an additional variable for injury setting, and developing a system for reporting return-to-sport date for time-loss injuries.DiscussionA multi-stage process of extensive planning, stakeholder feedback, and ongoing updates is required in order to successfully develop and implement an IIS system within a National Olympic and Paralynpic Committee. This process can be used to inform the development and implementation of IIS systems in other sporting organizations.

The Effect of Neurophysiological Modulation on Muscle Power and Pain Through Manual Therapy Over Electro- Physiotherapy for Athletes with Illio Tibial Band Syndrome (ITBS)

Introduction and Objectives: Iliotibial Band Syndrome (ITBS) is a common overuse injury in athletes, primarily impacting the knee and hip due to repetitive friction of the iliotibial band against the femur, resulting in pain and restricted hip abduction and knee extension. Muscle power and pain associated with ITBS can be measured using Hand-held Dynamometer (HHD) and Visual-Analog-Scale scores (VAS) respectively. This study aimed to compare the efficacy of two treatment groups, Manual-Therapy (MT) and Electro-Physiotherapy (EPT), in determining the most effective approach for managing ITBS. Materials and Methods: A RCT was conducted at the Sports Medicine Clinic of the Teaching Hospital Karapitiya, enrolling twenty athletes in each group as controls and experimental subjects. The control group received EPT, NSAIDS, and paracetamol for one week, while the experimental group received MT, NSAIDS, and paracetamol for the same duration. Muscle power and pain measurements were assessed using HHD & VAS on D1 and D28. P-values for statistical significance were obtained using RM-ANOVA followed by Bonferroni test. Results: Mean ages for EPT and MT groups were 24.4±6.6 and 25.4±6.6years, respectively. Muscle power (N) for EPT group on D1, and D28 were 101.7±26.3 and 112.7±23 respectively. The same parameters for MT group were 98.1±26 and 186.8±25.3. The mean differences for muscle power of two groups on D1 and D28 were -3.600(P=0.666) and 74.050(P<0.001). VAS scores for EPT group on D1, and D28 were 8.2±0.9 and 7±1 respectively. The same parameters for MT group were 7.9±0.8 and1.8±0.8. The mean differences for pain of two groups on D1 and D28 were 0.250(P=0.395) and -5.200(P<0.001). Partial-Eta-Squared for the two groups were 0.355 and 0.758respectively. ManualTherapy group’s higher effectiveness was statistically significant (p<0.001) and a 35.5% variance in muscle power and 75.8% variance in VAS score was attributable to it. Conclusion:Manual-therapy is superior to electro-physiotherapy in improving muscle power and decreasing in VAS scores of athletes with ITBS.

Medical examinations of professional and amateur athletes at a sports medicine clinic. Insights from a sports medicine specialist and cardiologist.

In 2019, three regulations of the Minister of Health regarding sports medicine examinations in children, adolescents and young athletes came into force. The publication presents in detail the current scope of tests and the frequency of required medical examinations necessary to obtain medical certificates qualify- ing patients to practice sports. The publication also presents the Regulation of the Minister of Health on the required qualifications of doctors authorized to issue medical certificates to athletes. It is very important to properly assess the health of potential and current athletes to ensure their safety while participating in sports competitions. There are diseases that increase the risk of sudden cardiac death which doctors should keep in mind when qualifying athletes for competition. The publication draws attention to the underestimated role of echocardiography and electrocardiographic stress testing.

Prognosticating Return-To-Play Time Following a Hamstring Strain Injury Using Early Flexibility Asymmetry and Musculoskeletal Ultrasound Imaging Outcomes: An Exploratory Study Among Canadian University Football Players.

Identify key flexibility and point-of-care musculoskeletal ultrasound (POCUS) measures for prognosticating return-to-play (RTP) following a first hamstring strain injury (HSI) and informing the clinical decision-making process. Exploratory prospective cohort study. Sport medicine and rehabilitation clinic of a Canadian university. One hundred and sixty-seven elite Canadian university football athletes followed over 5 seasons. Clinical and POCUS measures collected within 7 days after HSI and preseason clinical measures. Active knee extension (AKE) and Straight Leg Raise (SLR) to quantify hamstring flexibility, POCUS-related outcomes to characterize tissue alteration, and RTP until full sport resumption were documented (categorized as Early [1-40 days] or Late [>40 days] RTP). A total of 19 and 14 athletes were included in the Early RTP (mean RTP = 28.84 ± 8.62 days) and Late RTP groups (mean 51.93 ± 10.54 days), respectively, after having been diagnosed with a first HSI. For the clinical results, height and a greater flexibility asymmetry measure with the AKE or SLR when compared with both ipsilateral preseason and acute contralateral values significantly increases the chance of facing a long delay before returning to play (ie, RTP). For the POCUS-related results, the Peetrons severity score, extent of the longitudinal fibrillary alteration, and novel score lead to similar results. Early hamstring flexibility asymmetry following acute HSI, particularly the AKE, along with some POCUS-related measures are valuable in prognosticating late RTP following among Canadian university football athletes.

Predictors of Concussion Symptom Reporting Intention among Collegiate Athletes.

Underreporting of concussion symptoms in college athletics presents a challenge for sports medicine clinicians in evaluating and diagnosing such injuries. Some athletes do not report concussion symptoms because they do not recognize that they have a brain injury, however many athletes intentionally withhold symptoms to avoid removal from sport participation. To examine individual factors that influence college athletes' intentions to report concussion symptoms. Cross-sectional study. Collegiate athletics. 2,649 student-athletes from 23 sports, across 22 colleges/universities. The primary outcome was intention to report concussion symptoms. Predictor variables included demographics (age, race/ethnicity, sex, sport type, number of years in sport, number of previous concussions, and perceived concussion symptom knowledge), athletic identity, attitudes toward symptom reporting, perceived social pressure (injunctive and descriptive norms), and perceived behavioral control (capacity and autonomy). Hierarchical ordinary least squares regression revealed positive effects of attitude (b = .063; P = .005), descriptive norms (b = .131; P < .001), injunctive norms (b = .107; P < .001), and capacity (b = .196; P < .001) on intention to report symptoms. Athletic identity and participation in collision sports had small negative indirect effects on intention, while perceived concussion knowledge had a small positive indirect effect. The full regression model explained 14.24% of the variance in concussion reporting intention. These findings may help clinicians develop more focused interventions that address key social and individual determinants of underreporting, including attitude, injunctive and descriptive norms, and capacity to report. Athletic identity, sport type, and perceived understanding of concussion symptoms also influence reporting intention to a lesser extent. Previous research in this area has often failed to address a diverse population of college-age athletes from different sports and NCAA divisions.

Psychological readiness for injury recovery: evaluating psychometric properties of the IPRRS and assessing group differences in injured physically active individuals

ObjectivesThe primary purpose of the study was to assess the one-factor and two-factor structure of the Injury Psychological Readiness to Return to Sport Scale (IPRRS) in an injured physically active...

Symptom Exacerbation and Adverse Events during a Randomized Trial of Early-stage Concussion Rehabilitation.

Few studies utilize randomized clinical trials (RCT) to quantify clinical intervention safety of rehabilitation after sport-related concussion across sport levels. Describe symptom exacerbation and adverse events (AEs) associated with two concussion rehabilitation interventions. Cluster Randomized Controlled Trial (XXX). Sports medicine clinic and field settings. The RCT enrolled 251 concussed athletes (median age=20 years; female n=48) across 28 sites from New Zealand professional rugby (n=31), Canadian professional football (n=52), United States (U.S.)/Canadian colleges (n=128) and U.S. high schools (n=40). Two medically supervised interventions: 1) Enhanced Graded Exertion (EGE): international return to sport strategy and sport specific activities only (EGE-only n=119) and 2) Multidimensional Rehabilitation (MDR) followed by EGE: early symptom-directed exercises once symptoms were stable, followed by EGE after symptoms resolved (MDR+EGE n=132). Primary outcomes were intrasession total symptom severity score exacerbation and significant intersession (increase 10+ severity points) sustained total symptom severity exacerbation, each measured with a Postconcussion Symptom Scale (132 total severity points on scale). Reported AEs were also described. Activity-based rehabilitation sessions (n=1437) were the primary analysis unit. Frequencies, proportions, medians, and Interquartile Ranges (IQRs) were calculated for outcomes by treatment group. The 251 post-injury participants completed 1437 (MDR+EGE=819, EGE-only=618) activity-based intervention sessions. A total of 110 and 105 participants contributed data (those missing had no documented session data) to at least 1 activity-based session in the MDR+EGE and EGE-only arms respectively. Intrasession symptom exacerbations were equivilantly low in MDR+EGE and EGE-only arms (MDR+EGE: 16.7%, 95% CI:14.1%,19.1%; EGE-only: 15.7%, 95% CI: 12.8%,18.6%). In total, 9/819 MDR+EGE sessions (0.9%) and 1/618 EGE-only sessions (0.2%) resulted in a pre- to post-session symptom exacerbation beyond a 10+ severity point increase; 8/9 resolved to <10 points by the next session. Two study-related AEs (1 in each arm) were reported. Participants in MDR+EGE and EGE-only activities reported equivalently low rates of symptom exacerbation.