Associations between the circumstances and severity of head impacts in men's university ice hockey.

Improved evidence on the most common and severe types of head impacts in ice hockey can guide efforts to preserve brain health through improvements in protective gear, rink design, player training, and rules of play. In this observational cohort study of men's university hockey, we compared video evidence on the circumstances of 234 head impacts to measures of head impact severity (peak linear accelerations and rotational velocities) from helmet-mounted sensors (GForceTracker). Videos were analyzed with a validated questionnaire, and paired with helmet sensor data. Shoulder-to-head impacts were more common than hand- or elbow-, but there were no differences in head impact severity between upper limb contact sites (p ≥ 0.2). Head-to-glass impacts were nearly four times more common, and just as severe as head-to-board impacts (p ≥ 0.4). Head impacts resulting in major penalties (versus no penalty), or visible signs of concussion (versus no signs), involved greater head rotational velocities (p = 0.038 and 0.049, respectively). Head impacts occurred most often to the side of the head, along the boards to players in their offensive zone without puck possession. Head impact severity did not differ between cases where the head was (versus was not) the primary site of contact (p ≥ 0.6). Furthermore, penalties were called in only 4% of cases where the head was the initial point of contact. Accordingly, rules that focus on primary targeting of the head, while important and in need of improved enforcement, offer a limited solution.

Association Between Falls, Head Impacts, and Mortality Among Older Adults in Long-Term Care.

OBJECTIVES: Residents in long-term care (LTC) are at high risk for falls, and falls in LTC often result in impact to the head, with clinical consequences that may be challenging to detect. We examined whether the survival of LTC residents associates with falls and fall-related head impacts. DESIGN: Prospective cohort study. SETTING AND PARTICIPANTS: This study was conducted in 2 Vancouver-area LTC homes where falls were captured on video from surveillance cameras. A total of 232 participants (133 females, 99 males) experienced at least 1 fall captured on video, among whom 84% (n = 194) died between January 2011 and January 2020. The mean age at death was 86.5 (SD = 8.5) years, and the mean survival time after enrollment to this study was 3.8 (SD = 2.1) years. METHODS: Univariable and multivariable models were used to determine how survival time depended on the rate of falls (falls per 365 days), the percentage of falls on video involving head impact, sex, age at death, and baseline physical and cognitive status. RESULTS: On average, participants experienced 6.2 (SD = 7.0) falls per 365 days, and 36.9% (SD = 36.3) of video-captured falls resulted in head impact. In multivariable analyses, an increase of 1 fall per 365 days resulted in a 4.2% higher risk of death [hazard ratio (HR) = 1.042, 95% CI 1.023-1.062, P < .001]. A 1% increase in falls involving head impact resulted in an 0.5% higher risk of death (HR 1.005, 95% CI 1.001-1.010, P = .015). Participants who experienced head impact in all video-captured falls had a 50% higher risk for death than those who always avoided head impact. CONCLUSIONS AND IMPLICATIONS: Survival in LTC is associated with the rate of falls and percentage of falls involving head impact. Improved efforts are required to prevent falls in LTC, and reduce the frequency and consequences of head impacts during falls (eg, through compliant flooring).

Exaggerated postural sway improves orthostatic cardiovascular and cerebrovascular control.

Introduction: Healthy individuals with poor cardiovascular control, but who do not experience syncope (fainting), adopt an innate strategy of increased leg movement in the form of postural sway that is thought to counter orthostatic (gravitational) stress on the cardiovascular system. However, the direct effect of sway on cardiovascular hemodynamics and cerebral perfusion is unknown. If sway produces meaningful cardiovascular responses, it could be exploited clinically to prevent an imminent faint. Methods: Twenty healthy adults were instrumented with cardiovascular (finger plethysmography, echocardiography, electrocardiogram) and cerebrovascular (transcranial Doppler) monitoring. Following supine rest, participants performed a baseline stand (BL) on a force platform, followed by three trials of exaggerated sway (anterior-posterior, AP; mediolateral, ML; square, SQ) in a randomized order. Results: All exaggerated postural sway conditions improved systolic arterial pressure (SAP, p = 0.001) responses, while blunting orthostatic reductions in stroke volume (SV, p < 0.01) and cerebral blood flow (CBFv, p < 0.05) compared to BL. Markers of sympathetic activation (power of low-frequency oscillations in SAP, p < 0.001) and maximum transvalvular flow velocity (p < 0.001) were reduced during exaggerated sway conditions. Responses were dose-dependent, with improvements in SAP (p < 0.001), SV (p < 0.001) and CBFv (p = 0.009) all positively correlated with total sway path length. Coherence between postural movements and SAP (p < 0.001), SV (p < 0.001) and CBFv (p = 0.003) also improved during exaggerated sway. Discussion: Exaggerated sway improves cardiovascular and cerebrovascular control and may supplement cardiovascular reflex responses to orthostatic stress. This movement provides a simple means to boost orthostatic cardiovascular control for individuals with syncope, or those with occupations that require prolonged motionless standing.

Compensatory stepping responses during real-life falls in older adults.

BACKGROUND: Laboratory studies of postural responses suggest that stepping is a common strategy for balance recovery. Yet little is known about the frequency and characteristics of stepping responses during real-life falls in older adults. RESEARCH QUESTIONS: (1) Among falls experienced by older adults in long-term care (LTC), what is the prevalence of attempts to recover balance by stepping? (2) How often are steps aligned to the direction of the fall? (3) Do the prevalence and characteristics of steps associate with intrinsic and situational factors? METHODS: We collected and analyzed video footage of 1516 falls experienced by 515 residents of LTC (of mean age 82.7 years). Using generalized estimating equations, we tested whether the prevalence, direction and size of steps associated with sex, age, fall direction, activity at the time of falling, cause of imbalance, and holding or grasping objects. RESULTS: Stepping after imbalance was observed in 76% of falls, and 80% of these cases involved multiple steps. The direction of steps aligned with the initial fall direction in 81% of cases. The size of the first step was less than one-half foot length in 64% of cases. Secondary steps tended to be similar in size to the first step. Steps were more common for falls during walking than standing, and for sideways falls. Steps were less common in falls involving held objects, and steps were less likely to be aligned with the fall direction when reach-to-grasp responses were observed. SIGNIFICANCE: Older adults in LTC tended to respond to falls with multiple compensatory steps. Steps were tailored to the direction of the fall, but small in size (less than one-half foot length in size). Exercise programs for fall prevention in older adults should focus on increasing step size to enhance the effectiveness of step recovery responses.

Circumstances of Falls During Sit-to-Stand Transfers in Older People: A Cohort Study of Video-Captured Falls in Long-Term Care.

OBJECTIVE: To characterize the circumstances of falls during sit-to-stand transfers in long-term care (LTC), including the frequency, direction, stepping and grasping responses, and injury risk, based on video analysis of real-life falls. DESIGN: Cohort study. SETTING: LTC. PARTICIPANTS: We analyzed video footage of 306 real-life falls by 183 LTC residents that occurred during sit-to-stand transfers, collected from 2007 to 2020. The mean age was 83.7 years (SD=9.0 years), and 93 were female (50.8%). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: We used Generalized Estimating Equations to test for differences in the odds that a resident would fall at least once during the rising vs stabilization phases of sit-to-stand and to test the association between the phase of the transfer when the fall occurred (rising vs stabilization) and the following outcomes: (1) the initial fall direction; (2) the occurrence, number, and direction of stepping responses; (3) grasping of environmental supports; and (4) documented injury. RESULTS: Falls occurred twice as often in the rising phase than in the stabilization phase of the transfer (64.0% and 36.0%, respectively). Falls during rising were more often directed backward, while falls during stabilization were more likely to be sideways (odds ratio [OR]=1.95; 95% confidence interval [CI]=1.07-3.55). Falls during rising were more often accompanied by grasping responses, while falls during stabilization were more likely to elicit stepping responses (grasping: OR=0.30; 95% CI=0.14-0.64; stepping: OR=8.29; 95% CI=4.54-15.11). Injuries were more likely for falls during the stabilization phase than the rising phase of the transfer (OR=1.73; 95% CI=1.04-2.87). CONCLUSION: Most falls during sit-to-stand transfers occurred from imbalance during the rising phase of the transfer. However, falls during the subsequent stabilization phase were more likely to cause injury.

Perceived risk for falls and decision-making in riding raised ramps in mountain biking: a pilot study.

Mountain biking (MTB) is a challenging activity where riders face constant decisions on whether to attempt technical paths or features (e.g., wooden ramps and jumps) that pose risk for falls and injuries. Risk homeostasis theory posits that riders pursue an optimal non-zero level of risk that balances the rewards of attempting challenging features with the need to avoid unreasonable risk for injury. Little is known on how riders judge risk, and the level of risk that riders deem unacceptable. We conducted experiments with experienced MTB riders (n = 17) to examine how their willingness to ride raised wooden ramps depended on their perceived probability for falling (Pf) and their perceived probability for injury in the event of a fall (Pi) while riding the ramp. In one experiment, participants viewed ramps of varying widths and heights and described their willingness to ride each ramp, along with Pf and Pi. We found that Pf and Pi were independent predictors of willingness to attempt ramps. Moreover, the product Pf*Pi (the perceived risk for injury in attempting the ramp) was a stronger predictor than Pf or Pi alone. In a second experiment, participants viewed ramps of different widths, and reported the maximum (threshold) height where they would ride each ramp, along with Pf and Pi. We found that Pf*Pi at the threshold height, averaging 13%, did not vary with ramp width. We conclude that decisions on riding ramps are based on the product Pf*Pi. On average, riders refused to ride ramps when Pf*Pi exceeded 13%.

Protective responses of older adults for avoiding injury during falls: evidence from video capture of real-life falls in long-term care.

BACKGROUND: falls are common in older adults, and any fall from standing height onto a rigid surface has the potential to cause a serious brain injury or bone fracture. Safe strategies for falling in humans have traditionally been difficult to study. OBJECTIVE: to determine whether specific 'safe landing' strategies (body rotation during descent, and upper limb bracing) separate injurious and non-injurious falls in seniors. DESIGN: observational cohort study. SETTING: two long-term care homes in Vancouver BC. METHODS: videos of 2,388 falls experienced by 658 participants (mean age 84.0 years; SD 8.1) were analysed with a structured questionnaire. General estimating equations were used to examine how safe landing strategies associated with documented injuries. RESULTS: injuries occurred in 38% of falls, and 4% of falls caused injuries treated in hospitals. 32% of injuries were to the head. Rotation during descent was common and protective against injury. In 43% of falls initially directed forward, participants rotated to land sideways, which reduced their odds for head injury 2-fold. Upper limb bracing was used in 58% of falls, but rather than protective, bracing was associated with an increased odds for injury, possibly because it occurred more often in the demanding scenario of forward landings. CONCLUSIONS: the risk for injury during falls in long-term care was reduced by rotation during descent, but not by upper limb bracing. Our results expand our understanding of human postural responses to falls, and point towards novel strategies to prevent fall-related injuries.

Effects of the Mobility-Fit Physical Activity Program on Strength and Mobility in Older Adults in Assisted Living: A Feasibility Study.

Physical activity programs focusing on fall prevention often overlook upper-limb strength, which is important for transferring, balance recovery, and arresting a fall. We developed and evaluated a physical activity program, Mobility-Fit for older adults in Assisted Living (AL) that includes upper-limb strengthening, agility, coordination, and balance exercises. Thirty participants (85 ± 6 years) were recruited from two AL facilities; 15 were assigned to Mobility-Fit (three times/week, 45 min/session for 12 weeks) and 15 maintained usual care. Twenty-two participants (11 in each group) completed the study. We compared outcome changes between groups and interviewed participants and staff to explore the effectiveness and feasibility of the program. Among participants who attended Mobility-Fit, knee extension strength increased by 6%, reaction time decreased by 16%, and five-time sit-to-stand duration decreased by 15%. Conversely, participants in the usual care group had a 6% decrease in handgrip strength. Changes of these outcomes were significantly different between two groups (p < 0.05). Participants enjoyed the program and staff suggested some changes to improve attendance. Our results indicate that Mobility-Fit is feasible to deliver and beneficial for older adults in AL and may guide future clinical trials to evaluate the effectiveness of upper limb strengthening on safe mobility of older adults in care facilities.

Injuries from falls by older adults in long-term care captured on video: Prevalence of impacts and injuries to body parts.

BACKGROUND: Falls are the leading cause of injuries in older adults. However, most falls in older adults do not cause serious injury, suggesting that older adults may fall in a manner that reduces the likelihood of impact to body sites that are most vulnerable to injury. In this observational study of falls in long-term care (LTC), we tested whether body parts differed in their probability of impact and injury. METHODS: We recorded and analyzed videos of 2388 falls by 658 LTC residents (mean age 84.0 (SD = 8.1); 56.4% female). We used Linear Mixed Models to test for differences between body parts in the probability of impact and injury, and injury when impacts occurred. RESULTS: Injuries were reported in 38.2% of falls, and 85.9% of injuries involved direct impact to the injured body part. Impact occurred most often to the hip/pelvis (probability (standard error) = 0.95 (0.01); p < .001 relative to other body parts), and least often to the head (0.35 (0.01)). Conversely, injury occurred most often to the head (p < .001 relative to other body parts). The probability of injury when impacts occurred was 0.40 (0.01) for the head, and 0.11 or less for all other body parts. CONCLUSION: Our results help to explain why most falls by older adults in LTC do not cause serious injury: residents land on body parts that are the most resilient to injury. The high susceptibility of the head to injury reinforces the need to enhance upper limb protective responses for fall arrest. The dominant role of direct impact as the mechanism of injury supports approaches to attenuate impact forces through strategies like protective clothing and compliant flooring.

Accuracy of Kinovea software in estimating body segment movements during falls captured on standard video: Effects of fall direction, camera perspective and video calibration technique.

Falls are a major cause of unintentional injuries. Understanding the movements of the body during falls is important to the design of fall prevention and management strategies, including exercise programs, mobility aids, fall detectors, protective gear, and safer environments. Video footage of real-life falls is increasingly available, and may be used with digitization software to extract kinematic features of falls. We examined the validity of this approach by conducting laboratory falling experiments, and comparing linear and angular positions and velocities measured from 3D motion capture to estimates from Kinovea 2D digitization software based on standard surveillance video (30 Hz, 640x480 pixels). We also examined how Kinovea accuracy depended on fall direction, camera angle, filtering cut-off frequency, and calibration technique. For a camera oriented perpendicular to the plane of the fall (90 degrees), Kinovea position data filtered at 10 Hz, and video calibration using a 2D grid, mean root mean square errors were 0.050 m or 9% of the signal amplitude and 0.22 m/s (7%) for vertical position and velocity, and 0.035 m (6%) and 0.16 m/s (7%) for horizontal position and velocity. Errors in angular measures averaged over 2-fold higher in sideways than forward or backward falls, due to out-of-plane movement of the knees and elbows. Errors in horizontal velocity were 2.5-fold higher for a 30 than 90 degree camera angle, and 1.6-fold higher for calibration using participants' height (1D) instead of a 2D grid. When compared to 10 Hz, filtering at 3 Hz caused velocity errors to increase 1.4-fold. Our results demonstrate that Kinovea can be applied to 30 Hz video to measure linear positions and velocities to within 9% accuracy. Lower accuracy was observed for angular kinematics of the upper and lower limb in sideways falls, and for horizontal measures from 30 degree cameras or 1D height-based calibration.

Effective stiffness, damping and mass of the body during laboratory simulations of shoulder checks in ice hockey.

Ice hockey is a fast-paced sport with a high incidence of collisions between players. Shoulder checks are especially common, accounting for a large portion of injuries including concussions. The forces generated during these collisions depend on the inertial and viscoelastic characteristics of the impacting bodies. Furthermore, the effect of shoulder pads in reducing peak force depends on the baseline (unpadded) properties of the shoulder. We conducted experiments with nine men's ice hockey players (aged 19-26) to measure their effective shoulder stiffness, damping and mass during the impact stage of a shoulder check. Participants delivered a style of check commonly observed in men's university ice hockey, involving lateral impact to the deltoid region, with the shoulder brought stationary by the collision. The effective stiffness and damping coefficient of the shoulder averaged 12.8 kN/m and 377 N-s/m at 550 N, and the effective mass averaged 47% of total body mass. The damping coefficient and stiffness increased with increasing force, but there was no significant difference in the damping coefficient above 350 N. Our results provide new evidence on the dynamics of shoulder checks in ice hockey, as a starting point for designing test systems for evaluating and improving the protective value of shoulder pads.

Recreational Therapy to Promote Mobility in Long-Term Care: A Scoping Review.

The objective of this study was to explore and synthesize evidence on the effectiveness and implementation of recreational therapy programs to enhance mobility outcomes (e.g., balance, functional performance, fall incidence) for older adults in long-term care. The authors conducted a scoping review of 66 studies following the PRISMA guidelines. Two independent reviewers evaluated each article, and a third reviewer resolved discrepancies. Randomized controlled studies provided strong to moderate evidence that tai chi programs, walking, dancing, and ball games improve flexibility, functional mobility, and balance. Studies assessing program implementation highlighted that program delivery was facilitated by clear instruction, encouragement, attendance documentation, and minimal equipment. This review elucidated the benefit of recreational therapy programs on mobility. It also identified the need for customized programs based on individuals' interests and their physical and mental abilities. These findings and recommendations will assist practitioners in designing effective and feasible recreational therapy programs for long-term care.

Effect of Holding Objects on the Occurrence of Head Impact in Falls by Older Adults: Evidence From Real-Life Falls in Long-Term Care.

BACKGROUND: Falls cause approximately 80% of traumatic brain injuries in older adults, and nearly one third of falls by residents in long-term care (LTC) result in head impact. Holding objects during falls, such as mobility aids, may affect the ability of LTC residents to avoid head impact by arresting the fall with their upper limbs. We examined the prevalence of holding objects and their effect on risk for head impact during real-life falls in older adults living in LTC. METHODS: We analyzed videos of 1105 real-life falls from standing height by 425 LTC residents, using a validated questionnaire to characterize the occurrence of head impact and whether the resident held objects during descent and impact. We classified objects as either "weight-bearing" (via contact to the fixed environment, eg, chairs and walkers) or "non-weight-bearing" (eg, cups) and tested their effect on odds for head impact with generalized estimating equations. RESULTS: Residents held objects in more than 60% of falls. The odds for head impact were reduced for falls where weight-bearing objects were held or grasped during descent (odds ratio = 0.52; 95% confidence interval = 0.39-0.70) or maintained throughout the fall (odds ratio = 0.34; 95% confidence interval = 0.23-0.49). The most commonly held objects were chairs/wheelchairs (23% of cases), tables/counters (10% of cases), and walkers/rollators (22% of cases); all reduced the odds of head impact when held during descent. Holding non-weight-bearing objects did not affect the odds of head impact (odds ratio = 1.00; 95% confidence interval = 0.64-1.55). CONCLUSION: Our results show that older adults in LTC use held, weight-bearing objects to reduce their risk for head impact during falls.

American society of biomechanics journal of biomechanics award 2019: Circumstances of head impacts in men's university ice hockey.

This observational study examined the circumstances of head impacts in men's university ice hockey. Video footage was collected of 449 head impacts experienced by 37 players over 33 games. Videos were analyzed using a reliable, structured questionnaire to classify: playing zone, location on ice, puck possession, direction of gaze, object striking the head, location of head impact, trajectory of colliding players, and penalties. Generalized Linear Models were used to compare response categories for the proportion of players experiencing at least one head impact, and the number of head impacts per player. The majority of events resulting in head impact involved contact with another player (93%). Head impacts occurred most often to players who did not have puck possession, who were checked along the boards in their offensive zone. Players were just as likely to experience head impact with an environmental object, as with an opposing player's body part. Glass-to-head impacts represented 30% of cases, four times as common as board-to-head impacts. Hand-to-head impacts accounted for 23% of cases, twice as common as shoulder- or elbow-to-head impacts. In 27% of events, there were two or more successive impacts to the head (e.g., contact with shoulder and then boards). Only 16% of head impacts which involved contact with another player resulted in infractions. Our results support the need for additional research on the benefits of stricter rule enforcement, and modifications to the stiffness of glass and padding of gloves, for reducing the frequency and severity of head impacts in ice hockey.

The Effect of Fall Biomechanics on Risk for Hip Fracture in Older Adults: A Cohort Study of Video-Captured Falls in Long-Term Care.

Over 95% of hip fractures in older adults are caused by falls, yet only 1% to 2% of falls result in hip fracture. Our current understanding of the types of falls that lead to hip fracture is based on reports by the faller or witness. We analyzed videos of real-life falls in long-term care to provide objective evidence on the factors that separate falls that result in hip fracture from falls that do not. Between 2007 and 2018, we video-captured 2377 falls by 646 residents in two long-term care facilities. Hip fracture was documented in 30 falls. We analyzed each video with a structured questionnaire, and used generalized estimating equations (GEEs) to determine relative risk ratios (RRs) for hip fracture associated with various fall characteristics. All hip fractures involved falls from standing height, and pelvis impact with the ground. After excluding falls from lower than standing height, risk for hip fracture was higher for sideways landing configurations (RR = 5.50; 95% CI, 2.36-12.78) than forward or backward, and for falls causing hip impact (3.38; 95% CI, 1.49-7.67). However, hip fracture risk was just as high in falls initially directed sideways as forward (1.14; 95% CI, 0.49-2.67), due to the tendency for rotation during descent. Falling while using a mobility aid was associated with lower fracture risk (0.30; 95% CI, 0.09-1.00). Seventy percent of hip fractures involved impact to the posterolateral aspect of the pelvis. Hip protectors were worn in 73% of falls, and hip fracture risk was lower in falls where hip protectors were worn (0.45; 95% CI, 0.21-0.99). Age and sex were not associated with fracture risk. There was no evidence of spontaneous fractures. In this first study of video-captured falls causing hip fracture, we show that the biomechanics of falls involving hip fracture were different than nonfracture falls for fall height, fall direction, impact locations, and use of hip protectors. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

Effectiveness of Hip Protectors to Reduce Risk for Hip Fracture from Falls in Long-Term Care.

OBJECTIVE: To generate evidence of the effectiveness of hip protectors to minimize risk of hip fracture at the time of falling among residents of long-term care (LTC) by contrasting rates of hip fractures between falls with and without hip protectors. DESIGN: A 12-month, retrospective cohort study. We retrospectively reviewed fall incident reports recorded during the 12 months prior to baseline in participating homes. SETTING AND PARTICIPANTS: A population-based sample comprising all residents from 14 LTC homes owned and operated by a single regional health authority, who experienced at least 1 recorded fall during the 12-month study. RESULTS: At baseline, the pooled mean (standard deviation) age of residents in participating homes was 82.7 (11.3) years and 68% were female. Hip protectors were worn in 2108 of 3520 (60%) recorded falls. Propensity to wear hip protectors was associated with male sex, cognitive impairment, wandering behavior, cardiac dysrhythmia, use of a cane or walker, use of anti-anxiety medication, and presence of urinary and bowel incontinence. The incidence of hip fracture was 0.33 per 100 falls in falls with hip protectors compared with 0.92 per 100 falls in falls without hip protectors, representing an unadjusted relative risk (RR) of hip fracture of 0.36 (95% confidence interval 0.14-0.90, P = .029) between protected and unprotected falls. After adjusting for propensity to wear hip protectors, the RR of hip fracture was 0.38 (95% confidence interval 0.14-0.99, P = .048) during protected vs unprotected falls. CONCLUSIONS AND IMPLICATIONS: Hip protectors were worn in 60% of falls, and the risk of hip fracture was reduced by nearly 3-fold by wearing a hip protector at the time of falling. Given that most clinical trials have failed to attain a similar level of adherence, our findings support the need for future research on the benefits of dissemination and implementation strategies to maximize adherence with hip protectors in LTC.

The Flooring for Injury Prevention (FLIP) Study of compliant flooring for the prevention of fall-related injuries in long-term care: A randomized trial.

BACKGROUND: Fall-related injuries exert an enormous health burden on older adults in long-term care (LTC). Softer landing surfaces, such as those provided by low-stiffness "compliant" flooring, may prevent fall-related injuries by decreasing the forces applied to the body during fall impact. Our primary objective was to assess the clinical effectiveness of compliant flooring at preventing serious fall-related injuries among LTC residents. METHODS AND FINDINGS: The Flooring for Injury Prevention (FLIP) Study was a 4-year, randomized superiority trial in 150 single-occupancy resident rooms at a single Canadian LTC site. In April 2013, resident rooms were block randomized (1:1) to installation of intervention compliant flooring (2.54 cm SmartCells) or rigid control flooring (2.54 cm plywood) covered with identical hospital-grade vinyl. The primary outcome was serious fall-related injury over 4 years that required an emergency department visit or hospital admission and a treatment procedure or diagnostic evaluation in hospital. Secondary outcomes included minor fall-related injury, any fall-related injury, falls, and fracture. Outcomes were ascertained by blinded assessors between September 1, 2013 and August 31, 2017 and analyzed by intention to treat. Adverse outcomes were not assessed. During follow-up, 184 residents occupied 74 intervention rooms, and 173 residents occupied 76 control rooms. Residents were 64.3% female with mean (SD) baseline age 81.7 (9.5) years (range 51.1 to 104.6 years), body mass index 25.9 (7.7) kg/m2, and follow-up 1.64 (1.39) years. 1,907 falls were reported; 23 intervention residents experienced 38 serious injuries (from 29 falls in 22 rooms), while 23 control residents experienced 47 serious injuries (from 34 falls in 23 rooms). Compliant flooring did not affect odds of ≥1 serious fall-related injury (12.5% intervention versus 13.3% control, odds ratio [OR]: 0.98, 95% CI: 0.52 to 1.84, p = 0.950) or ≥2 serious fall-related injuries (5.4% versus 7.5%, OR: 0.74, 95% CI: 0.31 to 1.75, p = 0.500). Compliant flooring did not affect rate of serious fall-related injuries (0.362 versus 0.422 per 1,000 bed nights, rate ratio [RR]: 1.04, 95% CI: 0.45 to 2.39, p = 0.925; 0.038 versus 0.053 per fall, RR: 0.81, 95% CI: 0.38 to 1.71, p = 0.560), rate of falls with ≥1 serious fall-related injury (0.276 versus 0.303 per 1,000 bed nights, RR: 0.97, 95% CI: 0.52 to 1.79, p = 0.920), or time to first serious fall-related injury (0.237 versus 0.257, hazard ratio [HR]: 0.92, 95% CI: 0.52 to 1.62, p = 0.760). Compliant flooring did not affect any secondary outcome in this study. Study limitations included the following: findings were specific to 2.54 cm SmartCells compliant flooring installed in LTC resident rooms, standard fall and injury prevention interventions were in use throughout the study and may have influenced the observed effect of compliant flooring, and challenges with concussion detection in LTC residents may have prevented estimation of the effect of compliant flooring on fall-related concussions. CONCLUSIONS: In contrast to results from previous retrospective and nonrandomized studies, this study found that compliant flooring underneath hospital-grade vinyl was not effective at preventing serious fall-related injuries in LTC. Future studies are needed to identify effective methods for preventing fall-related injuries in LTC. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01618786.

Effect of body configuration at step contact on balance recovery from sideways perturbations.

Compensatory stepping is an important protective mechanism to prevent falling. To recover from sideways perturbations side steps are generally more advantageous than cross-over steps. However, there is lack of understanding of the characteristics of compensatory side steps following sideways perturbations that separate successful recoveries (i.e., no falls) from falls, the most clinically relevant outcome following a balance perturbation. We aimed to identify the critical determinants for successful side stepping after large sideways balance perturbations. Twelve healthy young adults were subjected to large leftward perturbations at varying intensities on a translating sheet. For recovery attempts started with a side step, we determined body configuration variables (frontal-plane leg and trunk angle) at first step contact, as well as spatiotemporal step variables (onset, length, duration, velocity). A logistic regression analysis was conducted to determine the predictive ability of body configuration and spatiotemporal variables on the probability of success (no fall vs. fall); perturbation intensity (peak jerk of translating sheet) and a random effect for individual were also included in the model. In the final model, leg angle and peak jerk were retained as predictors of successful balance recovery and these variables correctly classified the recovery outcome in 86% of the trials. This final 'body configuration' model yielded a -2 log likelihood of -36.3, whereas the best fitting model with only spatiotemporal variables yielded a -2 log likelihood of -45.8 (indicating a poorer fit). The leg angle at a given perturbation intensity appears to be a valid measure of reactive side step quality. The relative ease of measuring this leg angle at step contact makes it a candidate outcome for reactive stepping assessments in clinical practice.

A comparison of the magnitude and duration of linear and rotational head accelerations generated during hand-, elbow- and shoulder-to-head checks delivered by hockey players.

Ice hockey has the highest rates for concussion among team sports in Canada. In elite play, the most common mechanism is impact to the head by an opposing player's upper limb, with shoulder-to-head impacts accounting for twice as many concussions as elbow- and hand-to-head impacts combined. Improved understanding of the biomechanics of head impacts in hockey may inform approaches to prevention. In this study, we measured the magnitude and duration of linear and rotational head accelerations when hockey players (n = 11; aged 21-25) delivered checks "as hard as comfortable" to the head of an instrumented dummy with their shoulder, elbow and hand. There were differences in both peak magnitude and duration of head accelerations across upper limb impact sites, based on repeated-measures ANOVA (p < 0.005). Peak linear head accelerations averaged 1.9-fold greater for hand and 1.3-fold greater for elbow than shoulder (mean values = 20.35, 14.23 and 10.55 g, respectively). Furthermore, peak rotational head accelerations averaged 2.1-fold greater for hand and 1.8-fold greater for elbow than shoulder (1097.9, 944.1 and 523.1 rad/s2, respectively). However, times to peak linear head acceleration (a measure of the duration of the acceleration impulse) were 2.1-fold longer for shoulder than elbow, and 2.5-fold longer for shoulder than hand (12.26, 5.94 and 4.98 ms, respectively), and there were similar trends in the durations of rotational head acceleration. Our results show that, in body checks to the head delivered by varsity-level hockey players, shoulder-to-head impacts generated longer durations but lower magnitude of peak head acceleration than elbow- and hand-to-head impacts.