Sub-symptom threshold aerobic exercise for patients with persisting post-concussion symptoms and exercise intolerance after mild traumatic brain injury - a study protocol with a nested feasibility study for a randomized controlled trial.

BACKGROUND: Persistent post-concussion symptoms (PPCS) affect between 34 and 46% after a mild traumatic brain injury (mTBI). Many also experience exercise intolerance. Sub-symptom threshold aerobic exercise, SSTAE (exercise at an intensity level that does not increase symptoms) is proposed as a treatment to both reduce the symptom burden and increase the exercise tolerance after the injury. It is unclear if this also applies in a more chronic phase after mTBI. MAIN PURPOSE: The main purpose of this study is to evaluate whether SSTAE in addition to ordinary rehabilitation will lead to clinically meaningful improvement of symptom burden, normalize exercise tolerance, increase physical activity, improve health-related quality of life, and reduce patient-specific activity limitations compared to a control group that only receives ordinary rehabilitation. DESIGN: Randomized, controlled, single-blind parallel-group study with three measurement times; T0 at baseline, T1 after the intervention and T2 six months after T1. METHODS: Patients between the ages of 18 and 60 with exercise intolerance and persistent PPCS (> 3 months) will be recruited to the study and randomized to two groups. All patients will receive follow-up at the outpatient TBI clinic. The intervention group will in addition receive SSTAE for 12 weeks with exercise diaries and a retest every 3 weeks for optimal dosage and progression. The Rivermead post-concussion symptoms questionnaire will be the main outcome measure. The secondary outcome measure will be a test of exercise tolerance-the Buffalo Concussion Treadmill Test. Other outcome measures include the patient-specific functional scale that measures patient-specific activity limitations, as well as outcome measures for diagnosis-specific health-related quality of life, anxiety and depression, specific symptoms such as dizziness, headache and fatigue, and physical activity. DISCUSSION: This study will add knowledge about the effect of SSTAE and whether it should be implemented in rehabilitation for the adult population with persistent PPCS after mTBI. The nested feasibility trial showed that the SSTAE intervention was safe and that the study procedures and delivery of the intervention overall were feasible. However, minor amendments to the study protocol were made prior to the commencement of the RCT. TRIAL REGISTRATION: Clinical Trials.gov, NCT05086419. Registered on September 5th, 2021.

Head impact velocities in FIS World Cup snowboarders and freestyle skiers: Do real-life impacts exceed helmet testing standards?

INTRODUCTION: Prior to the 2013-2014 season, the International Ski Federation (FIS) increased the helmet testing speed from a minimum requirement of 5.4 to 6.8 m/s for alpine downhill, super-G and giant slalom and for freestyle ski cross, but not for the other freestyle disciplines or snowboarding. Whether this increased testing speed reflects impact velocities in real head injury situations on snow is unclear. We therefore investigated the injury mechanisms and gross head impact biomechanics in four real head injury situations among World Cup (WC) snowboard and freestyle athletes and compared these with helmet homologation laboratory test requirements. The helmets in the four cases complied with at least European Standards (EN) 1077 (Class B) or American Society for Testing and Materials (ASTM) F2040. METHODS: We analysed four head injury videos from the FIS Injury Surveillance System throughout eight WC seasons (2006-2014) in detail. We used motion analysis software to digitize the helmet's trajectory and estimated the head's kinematics in two dimensions, including directly preimpact and postimpact. RESULTS: All four impacts were to the occiput. In the four cases, the normal-to-slope preimpact velocity ranged from 7.0(±SD 0.2) m/s to 10.5±0.5 m/s and the normal-to-slope velocity change ranged from 8.4±0.6 m/s to 11.7±0.7 m/s. The sagittal plane helmet angular velocity estimates indicated a large change in angular velocity (25.0±2.9 rad/s to 49.1±0.3 rad/s). CONCLUSION: The estimated normal-to-slope preimpact velocity was higher than the current strictest helmet testing rule of 6.8 m/s in all four cases.

Injury rate and injury patterns in FIS World Cup Alpine skiing (2006-2015): have the new ski regulations made an impact?

BACKGROUND: New regulations for ski equipment were implemented prior to the 2012/2013 season in the International Ski Federation (FIS) Alpine World Cup (WC). OBJECTIVE: To investigate the effect of the new ski regulations on the rate and pattern of injuries by comparing data before (2006-2012) and after the implementation (2012-2015). METHODS: Injuries were recorded on the basis of the FIS Injury Surveillance System (FIS ISS) through retrospective interviews at the end of each of the nine WC seasons. All acute injuries that required medical attention were registered. Exposure was calculated on the basis of the official result lists. RESULTS: The absolute injury rate (injuries/100 athletes/season) was lower in the three seasons after the new ski regulations compared with the six seasons before (risk ratio (RR) 0.74, 95% CI 0.63 to 0.87). This was also the case for the relative injury rate (injuries/1000 runs) (RR 0.76, 95% CI 0.59 to 0.98). These changes were evident for male skiers, not for female skiers. There was a lower absolute injury rate for upper body injuries (RR 0.56, 95% CI 0.43 to 0.77), while no difference was found for lower extremity injuries (RR 0.84, 95% CI 0.70 to 1.01). CONCLUSIONS: We found a lower rate of injuries in the three seasons after the new ski regulation compared with the six seasons before. However, the ability to draw conclusions on the effects of the equipment change in subgroups of sex, discipline or body part is restricted by the limited statistical power.

Injuries in World Cup telemark skiing: a 5-year cohort study.

BACKGROUND: There are limited data on injuries in World Cup (WC) telemark skiing. OBJECTIVE: To describe the injury incidence and injury pattern seen among WC telemark skiers during the competitive season. METHODS: We interviewed all WC athletes (or their coach, if the athlete was not present) at the end of five winter seasons from 2008 until 2013. All acute injuries occurring in the competitive season that required the attention of medical personnel were registered. Exposure was calculated based on the official International Ski Federation (FIS) results database. RESULTS: 149 acute injuries were registered during 565 WC skier seasons. The absolute injury incidence was 26.4 injuries per 100 athletes per season (95% CI 22.1 to 30.6), higher for females than males (risk ratio (RR) 1.49, 95% CI 1.07 to 2.08). During the FIS WC competitions, 69 injuries were registered, corresponding to a relative incidence of 8.2 injuries per 1000 runs (95% CI 6.3 to 10.1). The most frequently injured body part was the knee (21%) followed by the hand-finger-thumb (20%), ankle (13%) and shoulder/clavicle (13%). The absolute risk of knee and shoulder/clavicle injuries was higher for females versus males (RR for knee injuries 2.72, 95% CI 1.35 to 5.51; RR for shoulder/clavicle injuries 2.55, 95% CI 1.06 to 6.14). No differences were detected in the injury incidence between disciplines. CONCLUSIONS: Female telemark skiers are at 1.5 times greater risk of injury than male skiers. The most commonly injured body part was the knee. The risk of knee and shoulder/clavicle injuries was higher for female athletes than for male athletes.

Head injuries among FIS World Cup alpine and freestyle skiers and snowboarders: a 7-year cohort study.

BACKGROUND: Traumatic brain injury is the leading cause of death for skiers and snowboarders. Fatal head injuries have also occurred at the International Ski Federation (FIS) World Cup (WC) level. We therefore wanted to describe the risk of head injuries across disciplines and sex among WC skiers and snowboarders. METHOD: We conducted retrospective interviews with FIS WC athletes at the end of seven consecutive seasons (2006-2013) to register injuries sustained during the competitive season. Head injuries were classified as 'head/face' injuries and did not include neck or cervical spine injuries. To calculate the exposure, we extracted data from the official FIS website for all WC competitions for each of the athletes interviewed. RESULTS: A total of 2080 injuries were reported during seven WC seasons. Of these, 245 (11.8%) were head/face injuries. Of the 245 head/face injuries reported, nervous system injuries/concussions were the most common (81.6%) and 58 of these were severe (23.7%). The injury incidence per 1000 competition runs was higher in freestyle (1.8, 95% CI 1.2 to 2.4) than in alpine skiing (0.9, 95% CI 0.6 to 1.2; risk ratio (RR) 2.05, 95% CI 1.25 to 3.46) and snowboard (1.0, 95% CI 0.6 to 1.3; RR 1.85, 95% CI 1.15 to 2.99). Women had a higher injury incidence (5.8, 95% CI 4.8 to 6.9) versus men (3.9, 95% CI 3.2 to 4.6; RR 1.48, 95% CI 1.15 to 1.90) throughout the season (per 100 athletes). CONCLUSIONS: The majority of head/face injuries were nervous system injuries/concussions and one in four injuries was severe. Freestyle skiers had the highest overall head injury incidence. Across all disciplines, the injury incidence was higher in women than in men.

Injury incidence in qualification runs versus final runs in FIS World Cup snowboard cross and ski cross.

BACKGROUND: In the International Ski Federation (FIS), World Cup (WC) snowboard cross (SBX) and ski cross (SX), the injury incidence in individual qualification runs versus final runs in heats of four athletes is unknown. Objective To investigate the injury incidence in individual qualification runs versus final runs of SBX and SX. METHODS: Injuries were recorded by the FIS injury surveillance system (FIS ISS) through retrospective athlete interviews at the end of each season during four WC seasons (2006-2010). A total of 713 athletes (345 SBX and 368 SX) were interviewed. Time-loss injuries occurring during SBX and SX competitions were included. Injury incidence was expressed as the relative injury rate (per 1000 runs). RESULTS: For SBX, the injury incidence per 1000 runs in finals was 12.1 vs. 6.1 in qualifications (RR 1.9, 95% CI 1.1-3.5). The injury incidence was 12.9 in finals and 4.4 in qualifications (RR 2.9, 95% CI 1.4-6.2) for SBX males and 10.5 vs. 9.3 (RR 1.1, 95% CI 0.5-2.8) for females. For SX, the injury incidence in finals was 12.4 and 9.2 in qualifications (RR 1.4, 95% CI 0.8-2.3). The injury incidence for SX males was 13.6 in finals vs. 8.8 in qualifications (RR 1.5, 95% CI 0.8-3.1) and10.8 vs. 9.8 (RR 1.1, 95% CI 0.5-2.6) for females. CONCLUSION: The injury incidence was significantly higher in final runs compared with qualification runs in SBX for males. For SBX females and in SX, no significant differences were found.