Epidemiology of Bone Stress Injuries and Healthcare Utilization in PAC-12 Cross-Country Athletes.

CONTEXT: Bone stress injury (BSI) is common in collegiate athletics. Injury rate and healthcare utilization is not well documented in running athletes. OBJECTIVE: The purpose of this study was to describe the rate, classification, and healthcare utilization in collegiate cross-country runners with BSI. DESIGN: Descriptive Epidemiology Study. SETTING: Sports medicine facilities participating in the PAC-12 Health Analytics Program. PATIENTS OR OTHER PARTICIPANTS: Collegiate cross-country athletes. MAIN OUTCOME MEASURES: Counts of injury and healthcare resources utilized for each injury. Injury rates were calculated based on athlete seasons. RESULTS: A total of 168 BSIs were reported over four seasons from 80 team season (M: 34, F: 46) and 1,220 athlete seasons, resulting in 1,764 AT services and 117 physician encounters. BSIs represented 20% of all injuries reported by cross-country athletes. The average bone stress injury rate was 0.14 per athlete season. Injury rates were higher in female athletes (0.16) compared to males (0.10) and rates were higher in the 2019-2020 season (0.20) compared to the 2020-21(0.14), 2018-2019 (0.12) and 2021-2022 (0.10) seasons. A majority of BSI's occurred in the lower leg (23.8%) and the foot (23.8%). Most injuries were classified as overuse and time-loss (73%) and accounted for the majority of AT services (75%) and physician encounters (73%). On average, there were 10.89 AT services per overuse-TL injury and 12.20 AT service per overuse-NTL injury. Mean occurrence was lower for physician encounters (0.70), prescription medications (0.04), tests (0.75), procedures (0.01), and surgery (0.02) compared to AT services. CONCLUSIONS: BSIs are common in collegiate cross- country runners and require considerable athletic training resources. Athletic trainers should be appropriately staffed for this population and suspected BSIs should b e confirmed with medical diagnosis. Future investigations should track treatment codes associated with BSI to determine best-practice patterns.

Acute and Overuse, Time-Loss and Non-Time-Loss Lateral Ankle Sprains and Health Care Utilization in Collegiate Student-Athletes.

CONTEXT: Health care utilization and the occurrence of non-time-loss (NTL) lateral ankle sprains is not well documented in collegiate athletes but could provide better estimates of injury burden and inform clinician workload. DESIGN: Descriptive epidemiologic study. METHODS: Lateral ankle sprain injury occurrence for Division I collegiate student-athletes in a conference with 32 sports representing 732 team seasons was collected during the 2018-2019 through 2020-2021 academic years. Injuries were designated as acute or overuse, and time-loss (TL) or NTL. Associated health care utilization, including athletic training services (AT services), and physician encounters were reported along with anatomical structures involved and season of occurrence. RESULTS: A total of 1242 lateral ankle sprains were reported over the 3 years from 732 team seasons and 17,431 player seasons, resulting in 12,728 AT services and 370 physician encounters. Most lateral ankle sprains were acute-TL (59.7%), which were associated with the majority of AT services (74.1%) and physician encounters (70.0%). Acute-NTL sprains represented 37.8% of lateral ankle sprains and were associated with 22.3% of AT services and 27.0% of physician encounters. On average, there were 12.7 (5.8) AT services per acute-TL sprain and 6.0 (3.6) per acute-NTL sprain. Most sprains involved "ankle lateral ligaments" (45.6%), and very few were attributed to overuse mechanisms (2.4%). CONCLUSIONS: Lateral ligament sprains are a common injury across many sports and result in substantial health care utilization from ATs and physicians, including NTL lateral ankle sprains. Although TL injuries were the majority of sprains, a substantial proportion of sprains were NTL and accounted for a considerable proportion of health care utilization.

Muscle activity during backward and forward running with body weight support.

We investigated muscle activity during backward (BR) and forward (FR) running with body weight support (BWS). Ten participants completed BR and FR on a lower body positive pressure treadmill while selecting a preferred speed (PS) for different BWS conditions (0%, 20%, 40%, 60%, and 80%BWS). Muscle activity from the rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and gastrocnemius (GA), rating of perceived exertion (RPE), preferred stride frequency (PSF), and PS were measured. Magnitude of muscle activity (BF, TA, and GA), RPE, PSF, and PS were not influenced by the interaction of direction and BWS (P>0.05). BF, TA, and GA were not different between directions (P>0.05) but were different between BWS conditions (P<0.01). RF was influenced by the interaction of direction and BWS (P<0.01). RF, BF, TA, and GA during BR were lower with increasing BWS. RF during BR was 59-86% higher than that of FR within BWS condition. RPE was lower with increasing BWS (P<0.001), regardless of direction of locomotion. PSF was lower and PS was higher during BR and FR with increasing BWS (both P<0.001). PSF during BR was 6-9% higher than that of FR. PS during BR was 24-31% lower than that of FR. These observations demonstrate that a change in BWS influences magnitude of muscle activity, PS, PSF, and RPE for both BR and FR. However, a change in direction of locomotion may not influence magnitude of muscle activity or RPE during running for a given BWS, even though muscle activity pattern, PS, and PSF were different between BR and FR.