The influence of novel compliant floors on balance control in elderly women--A biomechanical study

Effects of flooring on static and dynamic balance in young and older adults

BACKGROUND

Reducing fall-related injuries is difficult due to the multi-factorial nature of falls, and challenges in implementing injury-preventative strategies. While safety floors are effective at absorbing energy and reducing fall-related impact forces, the low stiffness component of these floors may impair an individual's balance and mobility, thereby increasing fall risk.

RESEARCH QUESTION

Therefore, the objective of this study was to investigate the influence of compliant flooring (i.e., safety flooring) on balance and mobility in young and older adults.

METHODS

Kinematics were measured with inertial measurement units from 20 young and 10 older adults. Static balance was evaluated during quiet stance on three flooring surfaces (traditional, safety, foam) with three stance positions (regular, tandem, one-legged). Mobility was evaluated using the 3 m timed-up-and-go test on two flooring surfaces (traditional, safety).

RESULTS

All participants were able to complete quiet standing trials on normal and safety flooring surfaces; however, most older adults could not complete one-legged stance trials or standing on foam. Significant age-related effects were observed for several balance and mobility tasks, particularly during the more challenging tandem stance condition, and the dynamic timed-up-and-go mobility test. In contrast, the introduction of safety flooring (compared to traditional flooring) had limited effects on balance/mobility (1 of 16 outcome variables showed negative effects).

SIGNIFICANCE

Overall, the findings demonstrate minimal effects of a novel safety floor compared to the age-related differences, and provide insights to assist researchers, consumers, and industry stakeholders in the development of environments that support safe movement and maintained independence for older adults.

Margins of postural stability in Parkinson's disease: an application of control theory

Introduction: Postural instability is a restrictive feature in Parkinson's disease (PD), usually assessed by clinical or laboratory tests. However, the exact quantification of postural stability, using stability theorems that take into account human dynamics, is still lacking. We investigated the feasibility of control theory and the Nyquist stability criterion-gain margin (GM) and phase margin (PM)-in discriminating postural instability in PD, as well as the effects of a balance-training program. Methods: Center-of-pressure (COP) data of 40 PD patients before and after a 4-week balance-training program, and 20 healthy control subjects (HCs) (Study1) as well as COP data of 20 other PD patients at four time points during a 6-week balance-training program (Study2), collected in two earlier studies, were used. COP was recorded in four tasks, two on a rigid surface and two on foam, both with eyes open and eyes closed. A postural control model (an inverted pendulum with a Proportional-integral-derivative (PID) controller and time delay) was fitted to the COP data to subject-specifically identify the model parameters thereby calculating |GM| and PM for each subject in each task. Results: PD patients had a smaller margin of stability (|GM| and PM) compared with HCs. Particularly, patients, unlike HCs, showed a drastic drop in PM on foam. Clinical outcomes and margins of stability improved in patients after balance training. |GM| improved early in week 4, followed by a plateau during the rest of the training. In contrast, PM improved late (week 6) in a relatively continuous-progression form. Conclusion: Using fundamental stability theorems is a promising technique for the standardized quantification of postural stability in various tasks.

Does sitting on a stability ball increase fall risk during ergonomic reaching tasks?

Although sitting on a stability ball has become an alternative to using an office chair, little is known about the increased potential for a fall on the deformable seat. This study examined differences in stability between sitting on a seat pan of a backless office chair and a stability ball during reaching tasks. Sixteen participants performed forward and lateral reaching tasks on a backless and armless office chair and stability ball while whole-body motion and force data under the seat were recorded. Even with participants placing their feet 16.5 cm wider when seated on the ball, the perceived fall risk was significantly greater. Centre of pressure displacement tended to be smaller under the ball for lateral reach directions, but larger during far anterior reaches. While not statistically significant, the medial-lateral margin of stability was on average 3.4 cm smaller on the ball. Despite attempts to increase stability by widening their stance, stability ball fall risk remained higher.

Age-related changes in protective arm reaction kinematics, kinetics, and neuromuscular activation during evoked forward falls

Fall related injuries in older adults are a major healthcare concern. During a fall, the hands and arms play an important role in minimizing trauma from ground impact. Although older adults are able to orient the hands and arms into a protective orientation after falling and prior to ground impact, an inability to avoid increased body impact occurs with age. Previous investigations have generally studied rapid arm movements in the pre-impact phase or absorbing energy in the post-impact phase. There are no known studies that have directly examined both the pre-impact and post-impact phase in sequence in a forward fall. The aim of this study was to identify age-related biomechanical and neuromuscular changes in evoked arm reactions in response to forward falls that may increase fall injury risk. Fourteen younger and 15 older adults participated. Falls were simulated while standing with torso and legs restrained via a moving pendulum system from 4 different initial lean angles. While there was not a significant age-related difference in the amount of energy absorbed post-impact (p = 0.68), older adults exhibited an 11% smaller maximum vertical ground reaction force when normalized to body weight (p = 0.031), and 8 degrees less elbow extension at impact (p = 0.045). A significant interaction between age and initial lean angle (p = 0.024), indicated that older adults required 54%, 54%, 41%, and 57% greater elbow angular displacement after impact at the low, medium, medium-high, and high initial lean angles compared to younger adults. These results suggested older adults may be at greater risk of increased body impact due to increased elbow flexion angular displacement after impact when the hands and arms are able to contact the ground first. Both groups exhibited robust modulation to the initial lean angle with no observed age-related differences in the initial onset timing or amplitude of muscle activation levels. There were no significant age-related differences in the EMG timing, amplitude or co-activation of muscle activation preceding impact or following impact indicating comparable neuromotor response patterns between older and younger adults. These results suggest that aging changes in muscular elements may be more implicated in the observed differences than changes in neuromuscular capacity. Future work is needed to test the efficacy of different modalities (e.g. instruction, strength, power, perturbation training, fall landing techniques) aimed at reducing fall injury risk.

Shock-absorbing flooring for fall-related injury prevention in older adults and staff in hospitals and care homes: the SAFEST systematic review

BACKGROUND

Injurious falls in hospitals and care homes are a life-limiting and costly international issue. Shock-absorbing flooring may offer part of the solution; however, evidence is required to inform decision-making.

OBJECTIVES

The objectives were to assess the clinical effectiveness and cost-effectiveness of shock-absorbing flooring for fall-related injury prevention among older adults in care settings.

REVIEW METHODS

A systematic review was conducted of experimental, observational, qualitative and economic studies evaluating flooring in care settings targeting older adults and/or staff. Studies identified by a scoping review (inception to May 2016) were screened, and the search of MEDLINE, AgeLine and Scopus (to September 2019) was updated, alongside other sources. Two independent reviewers assessed risk of bias in duplicate (using Cochrane's Risk of Bias 2.0 tool, the Risk Of Bias In Non-randomized Studies - of Interventions tool, or the Joanna Briggs Institute's qualitative tool).

RESULTS

Of the 22 included studies, 20 assessed the outcomes (three randomised controlled trials; and seven observational, five qualitative and five economic studies) on novel floors (n = 12), sports floors (n = 5), carpet (n = 5) and wooden subfloors (n = 1). Quantitative data related to 11,857 patient/resident falls (nine studies) and 163 staff injuries (one study). Qualitative studies included patients/residents (n = 20), visitors (n = 8) and staff (n = 119). Hospital-based randomised controlled trial data were too imprecise; however, very low-quality evidence indicated that novel/sports flooring reduced injurious falls from three per 1000 patients per day on vinyl with concrete subfloors to two per 1000 patients per day (rate ratio 0.55, 95% confidence interval 0.36 to 0.84; two studies), without increasing falls rates (two studies). One care home-based randomised controlled trial found that a novel underlay produces similar injurious falls rates (high-quality evidence) and falls rates (moderate-quality evidence) to those of a plywood underlay with vinyl overlays and concrete subfloors. Very low-quality data demonstrated that, compared with rigid floors, novel/sports flooring reduced the number of falls resulting in injury in care homes (26.4% vs. 33.0%; risk ratio 0.80, 95% confidence interval 0.70 to 0.91; three studies) and hospitals (27.1% vs. 42.4%; risk ratio 0.64, 95% confidence interval 0.44 to 0.93; two studies). Fracture and head injury outcomes were imprecise; however, hip fractures reduced from 30 per 1000 falls on concrete to 18 per 1000 falls on wooden subfloors in care homes (odds ratio 0.59, 95% confidence interval 0.45 to 0.78; one study; very low-quality evidence). Four low-quality economic studies concluded that shock-absorbing flooring reduced costs and improved outcomes (three studies), or increased costs and improved outcomes (one study). One, more robust, study estimated that shock-absorbing flooring resulted in fewer quality-adjusted life-years and lower costs, if the number of falls increased on shock-absorbing floors, but that shock-absorbing flooring would be a dominant economic strategy if the number of falls remained the same. Staff found moving wheeled equipment more difficult on shock-absorbing floors, leading to workplace adaptations. Staff injuries were observed; however, very low-quality evidence suggests that these are no less frequent on rigid floors.

LIMITATIONS

Evidence favouring shock-absorbing flooring is of very low quality; thus, much uncertainty remains.

CONCLUSIONS

Robust evidence is lacking in hospitals and indicates that one novel floor may not be effective in care homes. Very low-quality evidence indicates that shock-absorbing floors may be beneficial; however, wider workplace implications need to be addressed. Work is required to establish a core outcome set, and future research needs to more comprehensively deal with confounding and the paucity of hospital-based studies, and better plan for workplace adaptations in the study design.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42019118834.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 5. See the NIHR Journals Library website for further project information.

The SAFEST review: a mixed methods systematic review of shock-absorbing flooring for fall-related injury prevention

BACKGROUND

Shock-absorbing flooring may minimise impact forces incurred from falls to reduce fall-related injuries; however, synthesized evidence is required to inform decision-making in hospitals and care homes.

METHODS

This is a Health Technology Assessment mixed methods systematic review of flooring interventions targeting older adults and staff in care settings. Our search incorporated the findings from a previous scoping review, MEDLINE, AgeLine, and Scopus (to September 2019) and other sources. Two independent reviewers selected, assessed, and extracted data from studies. We assessed risk of bias using Cochrane and Joanna Briggs Institute tools, undertook meta-analyses, and meta-aggregation.

RESULTS

20 of 22 included studies assessed our outcomes (3 Randomised Controlled Trials (RCTs); 7 observational; 5 qualitative; 5 economic), on novel floors (N = 12), sports floors (N = 5), carpet (N = 5), and wooden sub-floors (N = 1). Quantitative data related to 11,857 patient falls (9 studies), and 163 staff injuries (1 study). One care home-based RCT found a novel underlay produced similar injurious falls rates (high-quality evidence) and falls rates (moderate-quality evidence) to a plywood underlay with vinyl overlay and concrete sub-floors. Very low-quality evidence suggested that shock-absorbing flooring may reduce injuries in hospitals (Rate Ratio 0.55, 95% CI 0.36 to 0.84, 2 studies; 27.1% vs. 42.4%; Risk Ratio (RR) = 0.64, 95% CI 0.44 to 0.93, 2 studies) and care homes (26.4% vs. 33.0%; RR 0.80, 95% CI 0.70 to 0.91, 3 studies), without increasing falls. Economic evidence indicated that if injuries are fewer and falls not increased, then shock-absorbing flooring would be a dominant strategy. Fracture outcomes were imprecise; however, hip fractures reduced from 30 in 1000 falls on concrete to 18 in 1000 falls on wooden sub-floors (OR 0.59, 95% CI 0.45 to 0.78; one study; very low-quality evidence). Staff found moving wheeled equipment harder on shock-absorbing floors leading to workplace adaptations. Very low-quality evidence suggests staff injuries were no less frequent on rigid floors.

CONCLUSION

Evidence favouring shock-absorbing flooring is uncertain and of very low quality. Robust research following a core outcome set is required, with attention to wider staff workplace implications.

TRIAL REGISTRATION

PROSPERO CRD42019118834 .

A comparison of floor surfaces for injury prevention in care settings: impact forces and horizontal pulling force required to move wheeled equipment

Shock-absorbing flooring is one potential solution to prevent fall-related injuries. No standards exist to characterize shock-absorbing healthcare flooring. This study explores two mechanical tests for impact force reduction and horizontal force required to move wheeled objects. An appropriately designed rubber underlay can reduce peak impact by 25% compared with 1% with standard vinyl.

INTRODUCTION

Severe falls often occur in hospitals and care homes. Shock-absorbing flooring is one potential solution to prevent fall-related injuries; however, no standards exist for characterizing flooring as an injury prevention measure. Shock-absorbing flooring use in high-risk settings may influence both patients (injury-saving potential) and staff (manoeuvring equipment). We aimed to explore two tests to characterize floors, to determine shock absorbency and horizontal pulling force required to move wheeled objects.

METHODS

Mechanical testing was performed according to the Canadian Standards Association Z325 Hip Protectors document. This test was developed for hip protectors but is applicable to compliant surfaces that form part of the floor. Tests were performed on commercially available floor materials (suitable for care settings) to assess the force required to initiate movement of a wheeled object across the floor. We explored the relationships between horizontal force required to pull wheeled objects, impact force, floor thickness, and core material.

RESULTS

Considerable differences were identified between floor samples in their ability to reduce the peak impact force (range 0.7-25%). A peak force reduction of up to 25% can be achieved with a specially designed rubber underlay. Horizontal pulling force increased with floor thickness but was lower for rubber floors. There was no direct relationship between impact attenuation and horizontal pulling force. Whilst thickness and core material explain some variations (66.5% for wheel movement; 82.3% for impact), other unmeasured factors clearly influence floor performance.

CONCLUSIONS

These results can inform the development of flooring and the establishment of standards needed to underpin practice, research, and development in this field.

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.

Influence of a brisk walking program on postural responses in sedentary older women: a randomised trial

This study analyzes the evolution in kinematic and non-linear stabilometric parameters in elderly sedentary women selected to participate in a brisk walking program. Ninety-four women were randomly selected for a program of 78 sessions over 6 months, with three sessions of 60 min per week. On the force platform, participants were assessed with both eyes opened as well as eyes closed during a period of 51.2 s and the sampling frequency was 40 Hz. The main dependent kinematic variables were the length, stabilogram surface, and the mean position in anteroposterior as well as medio-lateral directions. For the dynamic approach, we have selected the parameters of recurrence quantification analysis, sample entropy, and multiscale entropy. The kinematic and the time series analysis of group × time interactions demonstrated that 6 months of walk-training lacked influence on kinematic postural responses and on dynamical measurements. The weekly brisk walking program was situated on flat ground and consisted of three 60-min weekly sessions lasting 6 months, leading to no significant effect on postural responses. In regards to international recommendations brisk walking is a pertinent exercise. However, in older sedentary women, our study indicated a systemic lack of influence of 6 months' walk-training on flat ground on kinematic postural responses and on dynamical measures obtained by time series analysis.

Feasibility of Compliant Flooring in Long-Term Care: Results from a Stakeholder Symposium

Compliant flooring aims to prevent fall-related injuries among high-risk older adults in long-term care, but uptake of compliant flooring in this setting is limited. We hosted a one-day stakeholder symposium to identify advantages and disadvantages of implementing compliant flooring in long-term care and the most pressing directions for future research from the perspective of key stakeholders. Twenty-three stakeholders representing health care, industry, and research attended the symposium. Attendees believed the most important advantages of compliant flooring were reducing injuries in residents who have fallen, potential benefits to care staff, and potential increases in quality of life for residents. Attendees perceived the most significant disadvantages of compliant flooring were financial considerations, lack of research evidence, and challenges with installation. Attendees indicated a need for additional research on cost-effectiveness and clinical effectiveness. While stakeholders perceived compliant flooring to add value to long-term care, there are significant informational and financial barriers to uptake.

Compliant flooring to prevent fall-related injuries in older adults: A scoping review of biomechanical efficacy, clinical effectiveness, cost-effectiveness, and workplace safety

Background

Compliant flooring, broadly defined as flooring systems or floor coverings with some level of shock absorbency, may reduce the incidence and severity of fall-related injuries in older adults; however, a lack of synthesized evidence may be limiting widespread uptake.

Methods

Informed by the Arksey and O’Malley framework and guided by a Research Advisory Panel of knowledge users, we conducted a scoping review to answer: what is presented about the biomechanical efficacy, clinical effectiveness, cost-effectiveness, and workplace safety associated with compliant flooring systems that aim to prevent fall-related injuries in healthcare settings? We searched academic and grey literature databases. Any record that discussed a compliant flooring system and at least one of biomechanical efficacy, clinical effectiveness, cost-effectiveness, or workplace safety was eligible for inclusion. Two independent reviewers screened and abstracted records, charted data, and summarized results.

Results

After screening 3611 titles and abstracts and 166 full-text articles, we included 84 records plus 56 companion (supplementary) reports. Biomechanical efficacy records (n = 50) demonstrate compliant flooring can reduce fall-related impact forces with minimal effects on standing and walking balance. Clinical effectiveness records (n = 20) suggest that compliant flooring may reduce injuries, but may increase risk for falls. Preliminary evidence suggests that compliant flooring may be a cost-effective strategy (n = 12), but may also result in increased physical demands for healthcare workers (n = 17).

Conclusions

In summary, compliant flooring is a promising strategy for preventing fall-related injuries from a biomechanical perspective. Additional research is warranted to confirm whether compliant flooring (i) prevents fall-related injuries in real-world settings, (ii) is a cost-effective intervention strategy, and (iii) can be installed without negatively impacting workplace safety. Avenues for future research are provided, which will help to determine whether compliant flooring is recommended in healthcare environments.

External Hand Forces Exerted by Long-Term Care Staff to Push Floor-Based Lifts: Effects of Flooring System and Resident Weight

OBJECTIVE

The aim of this study was to investigate the effects of flooring type and resident weight on external hand forces required to push floor-based lifts in long-term care (LTC).

BACKGROUND

Novel compliant flooring is designed to reduce fall-related injuries among LTC residents but may increase forces required for staff to perform pushing tasks. A motorized lift may offset the effect of flooring on push forces.

METHOD

Fourteen female LTC staff performed straight-line pushes with two floor-based lifts (conventional, motor driven) loaded with passengers of average and 90th-percentile resident weights over four flooring systems (concrete+vinyl, compliant+vinyl, concrete+carpet, compliant+carpet). Initial and sustained push forces were measured by a handlebar-mounted triaxial load cell and compared to participant-specific tolerance limits. Participants rated pushing difficulty.

RESULTS

Novel compliant flooring increased initial and sustained push forces and subjective ratings compared to concrete flooring. Compared to the conventional lift, the motor-driven lift substantially reduced initial and sustained push forces and perceived difficulty of pushing for all four floors and both resident weights. Participants exerted forces above published tolerance limits only when using the conventional lift on the carpet conditions (concrete+carpet, compliant+carpet). With the motor-driven lift only, resident weight did not affect push forces.

CONCLUSION

Novel compliant flooring increased linear push forces generated by LTC staff using floor-based lifts, but forces did not exceed tolerance limits when pushing over compliant+vinyl. The motor-driven lift substantially reduced push forces compared to the conventional lift.

APPLICATION

Results may help to address risk of work-related musculoskeletal injury, especially in locations with novel compliant flooring.

Study protocol for the Flooring for Injury Prevention (FLIP) Study: a randomised controlled trial in long-term care

BACKGROUND

A promising strategy for reducing the incidence and severity of fall-related injuries in long-term care (LTC) is to decrease the ground surface stiffness, and the subsequent forces applied to the body parts at impact, through installation of compliant flooring that does not substantially affect balance or mobility. Definitive evidence of the effects of compliant flooring on fall-related injuries in LTC is lacking. The Flooring for Injury Prevention (FLIP) Study is designed to address this gap.

METHODS

The FLIP Study is a 4-year, parallel-group, 2-arm, randomised controlled superiority trial of flooring in 150 resident rooms at a LTC site. The primary objective is to determine whether compliant flooring reduces serious fall-related injuries relative to control flooring. Intervention (2.54 cm SmartCells compliant; 74 rooms) and control (2.54 cm plywood; 76 rooms) floorings were installed over the top of existing concrete floors and covered with identical 2.00 mm vinyl. The primary outcome is serious fall-related injury, defined as any impact-related injury due to a fall in a study room that results in Emergency Department visit or hospital admission. Secondary outcomes include minor fall-related injury, any fall-related injury, falls, number of fallers, fractures, and healthcare utilisation and costs for serious fall-related injuries. Randomisation of study rooms, and residents in rooms, was stratified by residential unit, and flooring assignments were concealed. Outcome ascertainment began September 2013.

DISCUSSION

Results from the FLIP Study will provide evidence about the effects of compliant flooring on fall-related injuries in LTC and will guide development of safer environments for vulnerable older adults.

TRIAL REGISTRATION NUMBER

NCT01618786.

Energy absorption during impact on the proximal femur is affected by body mass index and flooring surface

Impact mechanics theory suggests that peak loads should decrease with increase in system energy absorption. In light of the reduced hip fracture risk for persons with high body mass index (BMI) and for falls on soft surfaces, the purpose of this study was to characterize the effects of participant BMI, gender, and flooring surface on system energy absorption during lateral falls on the hip with human volunteers. Twenty university-aged participants completed the study with five men and five women in both low BMI (<22.5 kg/m(2)) and high BMI (>27.5 kg/m(2)) groups. Participants underwent lateral pelvis release experiments from a height of 5 cm onto two common floors and four safety floors mounted on a force plate. A motion-capture system measured pelvic deflection. The energy absorbed during the initial compressive phase of impact was calculated as the area under the force-deflection curve. System energy absorption was (on average) 3-fold greater for high compared to low BMI participants, but no effects of gender were observed. Even after normalizing for body mass, high BMI participants absorbed 1.8-fold more energy per unit mass. Additionally, three of four safety floors demonstrated significantly increased energy absorption compared to a baseline resilient-rolled-sheeting system (% increases ranging from 20.7 to 28.3). Peak system deflection was larger for high BMI persons and for impacts on several safety floors. This study indicates that energy absorption may be a common mechanism underlying the reduced risk of hip fracture for persons with high BMI and for those who fall on soft surfaces.

Novel safety floors do not influence early compensatory balance reactions in older adults

Novel safety flooring systems are a promising approach for reducing fall-related injuries in seniors, as they have been demonstrated to substantially reduce impact severity during falls, while minimally impairing balance control in community-dwelling older women. This pilot study aimed to characterize the potential effects of flooring conditions on dynamic balance control in retirement home-dwellers with more limited mobility. A tether-release paradigm was used to simulate a trip-type perturbation in 15 seniors across five flooring surfaces (three novel safety floors and one carpet compared to institutional-grade resilient rolled-sheeting). Kinetic and kinematic data tracked the displacement profiles of the underfoot centre-of-pressure and whole-body centre-of-mass, which were used to characterize compensatory balance reactions. Difference tests (ANOVA) found that the onset of the compensatory balance reaction was not associated with floor condition, nor were the timing and magnitude of peak centre-of-pressure excursion (minimum margin of safety) and velocity. Accordingly, the minimum margin of safety of the centre-of-mass was not significantly different across floors. Equivalence tests supported these findings. This study provides evidence that the carpet and novel safety floors tested do not negatively influence characteristics of initial dynamic balance responses following a lean-and-release perturbation compared to an institutional-grade resilient rolled-sheeting surface. In combination with reports of substantial force attenuative properties during fall-related impacts, these findings support the promise of novel safety floors as a biomechanically effective strategy for reducing fall-related injuries.

Cost--utility analysis of a shock-absorbing floor intervention to prevent injuries from falls in hospital wards for older people

BACKGROUND

hospital falls place a substantial burden on healthcare systems. There has been limited research into the use of hospital flooring as an intervention against fall-related injuries.

OBJECTIVE

to assess the cost-effectiveness of shock-absorbing flooring compared with standard hospital flooring in hospital wards for older people.

DESIGN

a cost-utility analysis was undertaken drawing upon data collected in a pilot cluster randomised controlled trial and the wider literature.

SETTING

the trial included eight hospital sites across England. Four sites installed shock-absorbing flooring in one bay, and four maintained their standard flooring.

MEASUREMENTS

falls and resulting injuries and treatment were reported by hospital staff. Data on destination of discharge were collected. Patients were followed up at 3 months and further resource use data were collected. Health-related quality of life was assessed, allowing quality-adjusted life years (QALYs) to be estimated. The incremental cost-effectiveness ratio of the shock-absorbing flooring was assessed compared with the standard hospital flooring.

RESULTS

in the base case, the shock-absorbing flooring was cost saving, but generated QALY losses due to an increase in the faller rate reported in the intervention arm. Scenario analysis showed that if the shock-absorbing flooring does not increase the faller rate it is likely to represent a dominant economic strategy-generating cost savings and QALY gains.

CONCLUSION

the shock-absorbing flooring intervention has the potential to be cost-effective but further research is required on whether the intervention flooring results in a higher faller rate than standard flooring.

Pilot cluster randomised controlled trial of flooring to reduce injuries from falls in wards for older people

BACKGROUND

falls disproportionately affect older people, who are at increased risk of falls and injury. This pilot study investigates shock-absorbing flooring for fall-related injuries in wards for frail older people.

METHODS

we conducted a non-blinded cluster randomised trial in eight hospitals in England between April 2010 and August 2011. Each site allocated one bay as the 'study area', which was randomised via computer to intervention (8.3-mm thick Tarkett Omnisports EXCEL) or control (2-mm standard in situ flooring). Sites had an intervention period of 1 year. Anybody admitted to the study area was eligible. The primary outcome was the fall-related injury rate. Secondary outcomes were injury severity, fall rate and adverse events.

RESULTS

during the intervention period, 226 participants were recruited to each group (219 and 223 were analysed in the intervention and control group, respectively). Of 35 falls (31 fallers) in the intervention group, 22.9% were injurious, compared with 42.4% of 33 falls (22 fallers) in the control group [injury incident rate ratio (IRR) = 0.58, 95% CI = 0.18-1.91]. There were no moderate or major injuries in the intervention group and six in the control group. The fall IRR was 1.07 (95% CI = 0.64-1.81). Staff at intervention sites raised concerns about pushing equipment, documenting one pulled back.

CONCLUSIONS

future research should assess shock-absorbing flooring with better 'push/pull' properties and explore increased faller risk. We estimate a future trial will need 33,480-52,840 person bed-days per arm.

The influence of body mass index and gender on the impact attenuation properties of flooring systems

The biomechanical effectiveness of safety floors has never been assessed during sideways falls with human volunteers. Furthermore, the influence of body mass index (BMI) and gender on the protective capacity of safety floors is unknown. The purpose of this study was to test whether safety floors provide greater impact attenuation compared with traditional flooring, and whether BMI and gender modify their impact attenuation properties. Thirty participants (7 men and 7 women of low BMI; 7 men and 9 women of high BMI) underwent lateral pelvis release trials on 2 common floors and 4 safety floors. As a group, the safety floors reduced peak force (by up to 11.7%), and increased the time to peak force (by up to 25.5%) compared with a traditional institutional grade floor. Force attenuation was significantly higher for the low BMI group, and for males. Force attenuation was greatest for the low BMI males, averaging 26.5% (SD = 3.0) across the safety floors. These findings demonstrate an overall protective effect of safety floors during lateral falls on the pelvis, but also suggest augmented benefits for frail older adults (often with low body mass) who are at an increased risk of hip fracture.

Quantification of the trade-off between force attenuation and balance impairment in the design of compliant safety floors

Safety floors (also known as compliant floors) may reduce the risk of fall-related injuries by attenuating impact force during falls, but are only practical if they do not negatively affect balance and mobility. In this study, we evaluated seven safety surfaces based on their ability to attenuate peak femoral neck force during simulated hip impacts, and their influence on center of pressure (COP) sway during quiet and tandem stance. Overall, we found that some safety floors can attenuate up to 33.7% of the peak femoral impact force without influencing balance. More specifically, during simulated hip impacts, force attenuation for the safety floors ranged from 18.4 (SD 4.3)% to 47.2 (3.1)%, with each floor significantly reducing peak force compared with a rigid surface. For quiet stance, only COP root mean square was affected by flooring (and increased for only two safety floors). During tandem stance, COP root mean square and mean velocity increased in the medial-lateral direction for three of the seven floors. Based on the substantial force attenuation with no concomitant effects on balance for some floors, these results support the development of clinical trials to assess the effectiveness of safety floors at reducing fall-related injuries in high-risk settings.

The influence of headform orientation and flooring systems on impact dynamics during simulated fall-related head impacts

Novel compliant flooring systems are a promising approach for reducing fall-related injuries in seniors, as they may provide up to 50% attenuation in peak force during simulated hip impacts while eliciting only minimal influences on balance. This study aimed to determine the protective capacity of novel compliant floors during simulated 'high severity' head impacts compared to common flooring systems. A headform was impacted onto a common Commercial-Carpet at 1.5, 2.5, and 3.5 m/s in front, back, and side orientations using a mechanical drop tower. Peak impact force applied to the headform (F(max)), peak linear acceleration of the headform (g(max)) and Head Injury Criterion (HIC) were determined. For the 3.5 m/s trials, backwards-oriented impacts were associated with the highest F(max) and HIC values (p<0.001); accordingly, this head orientation was used to complete additional trials on three common floors (Resilient Rubber, Residential-Loop Carpet, Berber Carpet) and six novel compliant floors at each impact velocity. ANOVAs indicated that flooring type was associated with all parameters at each impact velocity (p<0.001). Compared to impacts on the Commercial Carpet, Dunnett's post hoc indicated all variables were smaller (25-80%) for the novel compliant floors (p<0.001), but larger for Resilient Rubber (31-159%, p<0.01). This study demonstrates that during 'high severity' simulated impacts, novel compliant floors can substantially reduce the forces and accelerations applied to a headform compared to common floors including carpet and resilient rubber. In combination with reports of minimal balance impairments, these findings support the promise of novel compliant floors as a biomechanically effective strategy for reducing fall-related injuries including traumatic brain injuries and skull fractures.