P18. Backstroke Start Performance: The Impact of Using the Omega Backstroke Ledge

Background: FINA recently approved use of the “backstroke ledge” (Omega OBL2) to improve backstroke start performance in competition, but its performance has not been thoroughly evaluated. The purpose of this study was to compare starts performed on a flat wall to those performed with the OBL2, and to identify factors that contribute to better start performance. Methods: Ten elite backstroke swimmers performed three flat-wall and three OBL2 starts. Horizontal impulse, vertical impulse, takeoff velocity and takeoff angle were calculated from the force plate data. Entry distance, time to 10 m and start of hip and knee extension were recorded using digital video cameras. Results: We determined that starts performed with the OBL2 had a faster time to 10 m, less variability in vertical impulse and greater entry distance. Time to 10 m and head entry distance had a significant negative correlation. Starts with the OBL2 also had a trend toward lower resultant takeoff velocity, lower horizontal impulse and greater COM takeoff angle. Discussion and Conclusions: The OBL2 appears to provide a performance advantage by allowing an increased head entry distance, rather than larger impulse on the wall. Additional studies are needed to evaluate the factors that contribute to improved performance when using the OBL2. Coaches may consider head entry distance as a training target. Athletes should use the OBL2 in training and competition to ensure optimal start performance. Interdisciplinary Reflection: Concepts from physical and biological sciences are combined to explain the factors which affect backstroke start performance

P17. P3b event-related potentials show changes in varsity football players due to accumulated sub-concussive head impacts

BACKGROUND: Concussion has been a focus in football at all levels of participation. However, there is a growing appreciation that repetitive sub-concussive impacts may have more significant effects on overall neurological health than the isolated diagnosed concussions that have been the focus of recent research. The purpose of this study was to evaluate the relationship between the number of head impacts that players experience throughout the season and their P300 evoked potential. METHODS: Canadian university football players (n=45) were separated into three groups based on player mass and position/skill (small-skilled, big-skilled and big-unskilled). Groups were separated into low and high levels of impact exposure based on the total number of head impacts experienced in-season. Players completed baseline, midseason, postseason, and follow-up neurophysiological tests to measure P300 evoked potentials. Statistically significant differences between high versus low impact subgroups for each player group were assessed using independent-samples t-tests. RESULTS: Small-skilled and big-skilled players showed statistically significant decreases in P300 amplitude at midseason and postseason for high impact players compared to low impact players. Follow-up measures revealed that all groups were not significantly different compared to baseline measures. DISCUSSION & CONCLUSION: Players that experience a large number of head impacts in varsity football demonstrate significant decreases in specific EEG measures of cognitive function and information processing. INTERDISCIPLINARY REFLECTION: The combination of biomechanical head impact exposure with neurophysiological outcomes yields insight into the processes behind head impacts and their effects on the human brain

P19. Head impacts in youth soccer are comparable to American Football

Head Impacts in youth soccer are comparable to American Football Alexandra Harriss1, Aakash Naik1, David M. Walton2, James P. Dickey1 School of Kinesiology1, School of Physical Therapy2, Western University, London, Canada Background: Research has unequivocally demonstrated that females and youth soccer players are at a significant high risk of concussion. Recently, concerns for “heading” have been raised due to possible adverse neurological effects. While head impact accelerations and rotations have been investigated in American football, head impacts in youth soccer have not been rigorously studied. The purpose is to measure impact accelerations that result from different heading scenarios during youth soccer games. Methods: 16 players on an U-14 female youth soccer team were fitted with headbands instrumented with wireless sensors (GForceTracker, Artaflex Inc., Markham, Ontario, Canada) during eight soccer games. All games were video recorded to characterize heading scenario. Peak linear acceleration, and peak rotational velocity were recorded for each header. Results: A total of 126 header impacts were recorded, and long-range kicks accounted for 40% of all headers. Average header peak linear acceleration was 16.78 g and ranged from 7.96 g (ball deflection) to 38.62 g (drop kick). Average header peak rotational velocity was 1063 °/s and ranged from 37 °/s (long-range kick) to 2791 °/s (long-range kick). Discussions and conclusions: Header accelerations experienced by youth players depend on game scenario with largest impact accelerations from drop kicks and long-range kicks. Although the number of head impacts is smaller in soccer compared to American football, the impact magnitudes are comparable. Interdisciplinary Reflection: While the measured head accelerations are below injury thresholds, these data provide insight into the magnitude of head impacts in soccer and possible contribution to long-term cognitive deficits

Biofeedback as an intervention for persistent post-concussive symptoms: A randomized feasibility trial

Background Case reports indicate that low-resolution electromagnetic tomography neurofeedback and heart rate variability biofeedback may improve physiological functioning in individuals with persistent post-concussive symptoms. However, it is unclear whether larger-scale studies are feasible. Purpose To evaluate the feasibility of a combined low-resolution electromagnetic tomography neurofeedback and heart rate variability biofeedback intervention for individuals with persistent post-concussive symptoms. Methods Individuals with persistent post-concussive symptoms were randomized into intervention and control groups, and their baseline and post-test assessments were compared to a healthy control group. Outcomes included self-report questionnaires, resting electroencephalograph and electrocardiograph recordings, and a driving simulation task. Participants in the intervention group completed three 20 min low-resolution electromagnetic tomography neurofeedback sessions per week and at-home heart rate variability biofeedback training every morning and night for 8 weeks. Feasibility was evaluated according to recruitment capability and sample characteristics, data collection procedures, suitability of the intervention and study procedures, management and implementation of the study intervention, and preliminary participant responses to the intervention. Results Thirty-three individuals were recruited and 24 completed this study (seven intervention participants, nine persistent post-concussive symptoms control participants, and eight healthy control participants). One-quarter of participants (four intervention participants and three persistent post-concussive symptoms control participants) experienced simulator sickness during the driving simulator task and had to withdraw from the study. Intervention participants had an 88% and 86% compliance rate for the low-resolution electromagnetic tomography neurofeedback and heart rate variability biofeedback sessions, respectively. Low-resolution electromagnetic tomography neurofeedback sessions took approximately 1 h to complete per participant. Preliminary analysis indicated that the intervention reduced electroencephalograph z-score deviation with a very large effect size (d = 1.36) compared to the other study groups. Conclusions Pilot studies evaluating the efficacy of low-resolution electromagnetic tomography neurofeedback and heart rate variability biofeedback should be performed to confirm these preliminary findings. However, the protocol should be modified to reduce participant fatigue and withdrawal. This trial was registered with Clinicialtrials.gov (NCT03338036; https://clinicaltrials.gov/ct2/show/NCT03338036?term=03338036&draw=2&rank=1)

Graduate Keynote. Golf Grip Force Evaluation in Individuals with and without Hand Arthritis Using a New Wearable Sensor Technology

BACKGROUND Hand osteoarthritis (H-OA) is the most common type of osteoarthritis largely affecting individuals over 45. H-OA involves pain, loss of grip strength and limiting participation in recreational activities such as golf. Currently, a number of ‘arthritic’ grips are designed using joint protection principles to ‘reduce hand forces and tight gripping’. However, no comprehensive examinations in their effectiveness have been conducted. HYPOTHESIS The purpose of this study is to systematically analyse the hand forces produced from various golf grips and arthritis grips at the distal-phalanges of the hand-grip interface in individuals with and without hand arthritis using new wearable sensor technology. METHODS The finger forces in the hand were measured using Pressure Profiles FingerTPS system for participant’s bottom gripping hand thumb, index, middle and ring fingers. The participants performed 3 golf shots using a real ball on artificial turf with 12, mid-iron clubs fitted with various types of standard and arthritis grips. RESULTS Preliminary results of 4 healthy participants demonstrated that serrated style golf grips designed for players with arthritis produced some of the highest forces. Also, players with larger hand length measures produce higher forces in smaller diameter grips and small hand length measures in larger diameter grips. DISCUSSION These preliminary results demonstrate the possibility that ‘arthritic’ golf grips are not appropriately designed for the given user along with the potential relationship between grip geometry and hand size to finger forces. In better understanding the mechanics of arthritis and its relation to sports, the design of more advanced sporting equipment can be developed

A Mastication Mechanism Designed for Testing Temporomandibular Joint Implants

The development of temporomandibular joint implants has involved simplified mechanical tests that apply pure vertical forces or pure rotational movements to the implant. The aim of this study was to develop a biological based mastication mechanism and conduct preliminary testing of a novel temporomandibular joint implant. The mechanism was designed to mimic temporomandibular joint loads by performing compression and anterior/posterior translation. Pilot testing was performed on six implant/joint specimens for seven consecutive hours, completing approximately 22,000 cycles at a frequency of approximately 1 Hz. Each cycle had a joint compression phase (67.3 N over 0.15 s) followed by a translation phase (8.67 N over 0.43 s) that was similar to joint loads/motions that have been reported in vivo. This new mastication mechanism incorporates both anatomical and mechanical variability. The use of biological specimens is an important approach that can help bridge the gap between traditional synthetic implant materials/mechanical testing and in vivo testing

Impact of Biofeedback Interventions on Driving Performance in Individuals with Persistent Post-Concussive Symptoms

Low resolution electromagnetic tomography (LoRETA) neurofeedback and heart rate variability (HRV) biofeedback may improve driving ability by enhancing attention, impulse control, and peripheral vision, and reducing stress. However, it is unclear whether combined LoRETA neurofeedback and HRV biofeedback can improve driving performance for individuals experiencing persistent post-concussive symptoms (PPCS). In this study, seven individuals with PPCS completed an eight-week LoRETA neurofeedback and HRV biofeedback intervention. Changes in participants’ simulated driving performance and self-reported symptoms were measured and compared to two control groups: individuals with PPCS (n = 9), and healthy control participants (n = 8). Individuals in the intervention and PPCS control groups reported reduced PPCS severity (p < .05) compared to healthy control participants. Interestingly, individuals in the intervention group responded variably. These results indicate that more research is necessary to identify the subgroup of individuals that respond to LoRETA neurofeedback and HRV biofeedback and confirm these preliminary results