The research project aims to find out how special training influences the frequency and severity of injuries among female footballers in the top Swiss league. The project also aims to help establish normative values that are specifically tailored to women. The participating clubs will be randomly assigned to a comprehensive pre-season baseline examination with training recommendations based on the performed examinations (intervention group) or control group (normal training). Over the course of the 2024/2025 season, both groups will be compared in terms of the incidence and severity of concussions and musculoskeletal injuries. Initial results will be available in spring 2025 to coincide with the start of the European Women's Football Championship. The investigators' hypothesis is that the training recommendations in the intervention group will lead to a lower incidence of concussions and that the players will show better injury prevention as a result of these exercises.
All clubs in the top women's league in football will be contacted and asked to take part in the study. The baseline examinations will ideally take place in June and August 2024 to allow sufficient time to implement the training recommendations. The baseline examinations include a range of assessments addressing various systems potentially impacted by a concussion. These assessments encompass a standardized questionnaire, as well as vestibular, neurocognitive, balance, neck, and neurological evaluations. Due to the availability of the players, baseline examinations may also have to take place in September. The players in the intervention group are also given specific training recommendations for the prevention of head injuries, which are compiled by experts (neurologists, sports scientists, physiotherapists and neuroscientists). The exercise selection covers several areas that can be affected after a head injury. Each section contains 8 different exercises with increasing levels of difficulty (3x Basic-3x Intermediate-2x Advanced). The recommendations should be used as a warm-up program throughout the season before each training session. The coach or athletic coach will lead the warm-up program and ensure that each player follows the sequence and completes each phase according to the scheduled weeks. The warm-up program should be conducted as an 8-week cycle. The exercises are sent to the coaching staff in writing and by means of a video using our Neuroreha-Tool app. The coaches have access to the specific prescribed exercises. Each exercise is repeated 2-3 times and each exercise takes 50 seconds. In total, the warm-up will take 10-15 minutes. During the football season from August 2024 to April 2025, players (both intervention and control groups) will be asked every two weeks to submit information about any injuries sustained in the match via the My REDCap app or the REDCap online survey. In the event of an injury, the date, type, and injured body region will be recorded via REDCap. Training adherence will also be documented for both groups (intervention group: number of training minutes for specific vestibulo-oculomotor and/or neuromuscular training exercises; control group: minutes of regular training). After 8 weeks, a follow-up of the standard baseline tests will be repeated to measure the effects of the training recommendations. Each player receives a short report on the results of their examination within one week of the follow-up examination. If a player suffers a concussion, they will be asked to complete the post-concussion symptom scale (PCSS). Players can also indicate if they wish to be contacted by the BrainCare institute for targeted diagnostics and/or therapy. On the day of the baseline examination, players will be thoroughly informed about the definition and correct recording of all endpoints collected in the follow-up. This information will also be available online on the app at any time. A recently published study confirms the usefulness and user-friendliness of a mobile app for monitoring training adherence and assessing pain using a pain rating scale. Once a month, the club's contact person - ideally a member of the medical team who was also present at the baseline test - is contacted by the project management to verify the information and record the severity (i.e. the number of days the player is out of action) of injuries. The number of match appearances played (in hours) is determined using Power BI from the Swiss Football Association (football.ch).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
209
The players in the intervention group are also given specific training recommendations for the prevention of head injuries, which are compiled by experts (sports scientists, physiotherapists and neuroscientists). The exercise selection covers several areas that can be affected after a head injury. Each section contains 8 different exercises with increasing levels of difficulty (3x Basic-3x Intermediate-2x Advanced). The recommendations should be used as a warm-up program throughout the season before each training session. The coach or athletic coach will lead the warm-up program and ensure that each player follows the sequence and completes each phase according to the scheduled weeks. The warm-up program should be conducted as an 8-week cycle.
Incidence of injury frequency
Injury frequency will be gauged via REDCap questionnaires, capturing date, type, and injured region. Training adherence will be noted: the intervention group reports specific vestibulo-oculomotor and/or neuromuscular exercise minutes, while the control group reports normal training minutes. Concussed players complete the Post-Concussion Symptom Scale (PCSS). The PCSS is designed to quantify the range and severity of symptoms that can occur after a concussion. It helps healthcare professionals monitor changes in symptoms over time and make informed decisions about an individual's recovery and readiness to return to activities.Each symptom is rated on a scale, typically from 0 to 6, where 0 means the symptom is not present and 5-6 indicates severe severity. Questionnaires occur at baseline, 8-week follow-up, and biweekly until season end for all players.
Time frame: 1 year
Clinical cervical spine/jaw exam:
The examination of the cervical spine and the surrounding tissue is used to identify cervical causes of headaches. Assessments include range of motion (degrees) and isometric strength (N) for the cervical spine, and extent of movement and deviation of mouth opening (degrees) for the jaw.
Time frame: 1 year
Video-Head Impulse Test (vHIT)
Passive, fast and low-amplitude rotational movements (head impulses, 10-15° eccentricity) are performed in the planes of each pair of semicircular canals (horizontal, RALP (right front-left rear), LARP (left front-right rear)) and induce VOR responses. During the examination, the subject is asked to fixate a target straight ahead. The eye movements during the VOR are measured with a high-speed video camera. Evaluation of gain (ratio between head and eye movement) and presence of saccades (rapid, corrective eye movements) are measured.
Time frame: 1 year
Dynamic Visual Acuity (DVA)
During the DVA, visual acuity is determined during head movements in order to measure the effectiveness of the visual stabilization function. Static visual acuity (visual acuity without head movement) is determined by reducing the size of a Landolt with C on a computer screen until the athlete is no longer able to read it correctly. The visual acuity is then obtained with head movements (120°/s, ±30°). If the difference between the static and dynamic visual acuity is more than 0.2 logMAR, there is a visual stabilization disorder.The difference between static and dynamic visual acuity is assessed in logMAR.
Time frame: 1 year
Vestibulo/Oculomotor Screening (VOMS)
The VOMS tests eye movements and vestibulo-oculomotor coordination. The screening covers five areas: Smooth pursuit, horizontal and vertical saccades, near convergence distance, horizontal vestibular eye reflex and visual motion sensitivity. For each area, the symptoms are rated on a Visual analogue scale (VAS), typically from 0 to 10, where 0 means the symptom is not present and 8-10 indicates severe severity. The near point convergence distance is measured in centimeters (cm).
Time frame: 1 year
Modified Balance Error Scoring System-Test (BESS)
BESS is a reliable and inexpensive tool to measure static balance. BESS consists of 6 tests that include both leg stance, one leg stance and tandem stance conditions, respectively, on both hard and foam surfaces with eyes closed. A stopwatch is used to determine participants' time during 20-second stance tests. The grading method is based on the score of the error table in the six tests. Errors include lifting the hip, walking, opening the eyes, grasping something, falling, leaving the test position after 5 seconds, flexion or abduction of the upper leg more than 30 degrees, and lifting the heel or front of the leg on the surface. If more than one mistake is made at the same time, they are counted as one mistake. The maximum total number of errors for any test is taken to be 10 (a higher score indicates mor balance errors and greater balance impairment).
Time frame: 1 year
Dual Task - Concussion Balance Test (COBALT)
The COBALT assesses balance through 5 conditions: 1 single-task and 4 dual-task. Participants are timed for 20 seconds using a stopwatch. In the single-task, they count backwards by 7s from 100. Dual-task conditions combine balance exercises with the cognitive task, with and without foam: 1. Double leg stance with eyes closed, head rotating side to side to a metronome at 120 bpm. 2. Eyes open, arms outstretched, thumbs up, focusing on thumbs while rotating side to side to a metronome at 40 bpm. Scoring uses an error table across conditions. Errors include cognitive mistakes, hip lifting, walking, eye opening, grasping, falling, leaving position early, leg movement beyond 30 degrees, and not syncing head or trunk rotation with the metronome. Each test's maximum errors are 10, with higher scores indicating more balance issues and impairment.
Time frame: 1 year
Postural Control - Sway path length
Sway path length measurement using an accelerometer involves tracking the movement of the center of pressure (COP) during the BESS and COBALT. This measure provides an objective assessment of postural control by quantifying the total distance the COP travels. An accelerometer is placed on the hip to capture the body's movements, and the data is analyzed using specialized balance software. The sway path length is measured in millimeters (mm).
Time frame: 1 year
Postural Control - sway path velocity
Sway path velocity measurement involves quantifying the speed at which the center of pressure (COP) moves. This parameter provides an objective assessment of postural control by indicating how quickly the COP travels. An accelerometer is placed on the hip to capture the body's movements, and the data is analyzed using specialized balance software. The measure is performed during the BESS and COBALT. The sway path velocity is measured in millimeters per seconds (mm/s).
Time frame: 1 year
Latency in horizontal saccades
Saccade latency in milliseconds (ms) during horizontal paradigms. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.
Time frame: 1 year
Latency in vertical saccades
Saccade latency in milliseconds (ms) during vertical paradigms. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.
Time frame: 1 year
Velocity in horizontal saccades
Saccade velocity in degrees per seconds (˚/s) during horizontal paradigms. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.
Time frame: 1 year
Velocity in vertical saccades
Saccade velocity in degrees per seconds (˚/s) during vertical paradigms. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.
Time frame: 1 year
Horizontal smooth pursuit gain
The gain refers to the accuracy with which the eyes match the velocity of a moving target. It is a measure of how well the eye movement system keeps up with the speed of the moving object in the horizontal plane. Specifically, gain is calculated as the ratio of eye movement velocity to target velocity. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.
Time frame: 1 year
Vertical smooth pursuit gain
The gain refers to the accuracy with which the eyes match the velocity of a moving target. It is a measure of how well the eye movement system keeps up with the speed of the moving object in the vertical plane. Specifically, gain is calculated as the ratio of eye movement velocity to target velocity. The participant sits in front of a computer screen displaying a moving symbol, which they must follow without moving their head. Eye movements are recorded and analyzed using an eye-tracking device.
Time frame: 1 year
Pupillometry - Amplitude
Pupillometry is the measurement and analysis of pupil size and its response to light stimuli. The amplitude i.e maximum constriction is the difference between the baseline pupil size and the smallest pupil size achieved after exposure to the light stimulus. The amplitude is measured in millimeters (mm).
Time frame: 1 year
Pupillometry - Velocity
Pupillometry is the measurement and analysis of pupil size and its response to light stimuli. The velocity is the speed at which the pupil constricts or dilates in response to changes in light intensity. Typically reported in millimeters per second (mm/s).
Time frame: 1 year
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