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



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.


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.


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.


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.

Peer Review reports


Addressing matters of health and safety through environmental design interventions is a long-standing and diverse discipline [1]. In geriatric care settings, one of the most prevailing safety concerns are falls and their associated injuries, the most severe of which include fractures and head injuries [2, 3]. Falls can cause lasting consequences for health, independence, functioning, and wellbeing, and are particularly discriminatory against older age groups who are more at risk of low-impact trauma and vulnerability to adverse health outcomes due to frailty [4, 5]. With a complex aetiology and array of risk factors [6,7,8], there remains no panacea for preventing falls and related injuries, and environmental design is therefore considered one potential tool in a repertory of interventions, including exercise and multifactorial approaches targeting individual risk factors [9].

The consensus definition of a fall being of “an unexpected event in which the participants come to rest on the ground, floor, or lower level” presents the most obvious target for environmental intervention [10]. Shock-absorbing flooring aims to reduce the stiffness of the ground surface to lower the impact forces experienced from a fall to help mitigate injury. A standard rigid floor, prevalent in care settings, may comprise a concrete sub-floor with a resilient sheet-vinyl covering (approximately 2 mm thick) [11]. Yet variations exist on this norm; commonly used floor materials such as carpet, wooden sub-floors, and thicker underlays, may variably afford softer landings for people who fall [12, 13]. In the sports sector, floor materials have been designed to offer shock-absorbency for the comfort and protection of players, and some of these designs have been repurposed for use in hospitals and care homes [14]. More recently, flooring manufacturers have started to target the gap in the market for specially-designed ‘health’ floors to support injurious falls prevention in care settings [15, 16].

Flooring interventions offer various appeals, as they form part of the ambient environment; they do not require any active user compliance, in contrast to hip protectors or helmets, which only target specific body locations. With an expected longevity of up to 20 years, a flooring intervention presents the opportunity for a significant return on investment [17,18,19,20]. If proven effective at preventing hip fractures for example (which have been estimated to incur upwards of USD 6500 per fracture to various international health systems, often considerably more [21,22,23]), the cost of purchasing and installing a new floor could be quickly recouped. Yet rarely do interventions come without risk, and for shock-absorbing flooring interventions the concerns are twofold: 1) the debated potential for a softer surface to inadvertently increase the risk of falling for those already unsteady on their feet [24,25,26,27,28,29,30,31,32,33,34,35]; and 2) the risk to staff who may find manoeuvring wheeled equipment (such as beds and trolleys) harder, due to greater resistance to pushing and pulling forces [36,37,38,39], potentially increasing the risk of musculoskeletal injuries [40, 41].

A scoping review identified all of the evidence on shock-absorbing flooring published to May 2016 [42]. This systematic review updated the search performed by the scoping review, and to our knowledge is the first to systematically synthesise the evidence on shock-absorbing flooring use in care settings, to help inform practice. This is an abridged report of the review, which is published in full as a Health Technology Assessment [43]. Our objectives were to:

  1. 1)

    Assess the potential benefits (fall-related injury prevention) and risks (falls; staff injuries) of different flooring systems in care settings;

  2. 2)

    Assess the extent to which these potential benefits and risks may be modified by different study/setting, intervention and participant characteristics;

  3. 3)

    Critically appraise and summarise current evidence on the resource use, costs and cost-effectiveness of shock-absorbing flooring in care settings for older adults, compared with standard flooring;

  4. 4)

    Summarise findings on the implementation of flooring interventions in the included studies;

  5. 5)

    Summarise the views and experiences of shock-absorbing flooring use from staff, patients’, residents’ and visitors’ perspectives;

  6. 6)

    Identify gaps in existing evidence.


In this mixed methods review (including randomised, non-randomised, qualitative, and economic studies), we aimed to systematically review the evidence on shock-absorbing flooring use in care settings (hospitals and care homes) for fall-related injury prevention in older adults, to understand what is known about the effectiveness, cost-effectiveness, and qualitative experiences of shock-absorbing flooring use. We followed established approaches and reporting standards in conducting this review [44,45,46,47], which was guided by our protocol (registration: PROSPERO CRD42019118834) [48].

Eligibility criteria

We placed no restrictions on publication status, date, or language of reports, but rather studies needed to satisfy the following characteristics:

Types of studies

We included primary research involving experimental, quasi-experimental, observational, and qualitative designs, and partial and full economic evaluations based on a single study or model. Laboratory/biomechanical studies, and simple before-and-after quantitative studies with no evaluation of time trends or concurrent control, were excluded.


Our target population was broadly older adults in hospitals and care homes. Adverse events pertaining to staff were also included. Qualitative evidence evaluating the views of any individuals occupying the same environment was also eligible. Studies must have focussed on adult populations (paediatric settings were excluded); however, we did not set a strict threshold for ‘older adults’, since chronological age may not be a good indicator of frailty [49, 50], and due to the nature of the intervention we anticipated studies would have been conducted in locations where individuals were at risk of falls.


Studies conducted in hospitals (acute, sub-acute), intermediate and long-term care settings (nursing and care homes) were eligible. Private housing, and other settings (e.g. sporting venues) were excluded.


Studies must have compared different flooring types, with at least one of the comparison groups classifiable as a ‘shock-absorbing’ floor, that is: floor coverings, underlays, and sub-floors considered to reduce the impact forces of falls. We included purposely-designed (novel) injury-prevention flooring systems, sports flooring repurposed for care setting use, carpet with or without underlay, and other combination flooring systems (e.g. vinyl overlays with padded underlays such as foam, or rubber, or wooden sub-floors). Studies involving flooring as part of a multiple-component intervention in which the effects of the floor were not discernible from the other intervention components were not eligible. Flooring is permanently affixed to the ground, providing universal coverage; therefore, fall mat interventions were excluded. Studies were eligible if they compared different types of shock-absorbing flooring systems, or a shock-absorbing floor to a standard ‘rigid’ floor (e.g. concrete, ≤2 mm vinyl/resilient sheeting). In this abridged report, we have focussed on our main comparison “any shock-absorbing flooring versus standard flooring”.


The reporting of specific outcomes did not form part of our eligibility criteria.

Outcomes and prioritisation

Our pre-specified outcomes were developed, and prioritised, based on related core outcome sets, public involvement, wider stakeholder engagement [51], and peer review feedback on our protocol [48].

Primary outcomes:

  1. (1)

    Injurious falls rate per 1000 person days;

  2. (2)

    Falls rate per 1000 person days.

Secondary outcomes:

  1. (3)

    Number of falls with injuries (e.g. none, minor, moderate, severe, death);

  2. (4)

    Number of fractures;

  3. (5)

    Number of hip fractures;

  4. (6)

    Number of fallers;

  5. (7)

    Number of adverse events (staff injuries);

  6. (8)

    Number of head injuries;

  7. (9)

    Fractures per 1000 person days;

  8. (10)

     Hip fractures per 1000 person days;

  9. (11)

     Qualitative outcomes (e.g. staff, patient/resident, and visitor attitudes, views, and experiences);

  10. (12)

     Economic outcomes (to include assessments of quality-adjusted life years);

  11. (13)

     Process outcomes (e.g. ease of, or problems with, flooring installation).

Search methods

We incorporated the search results from a scoping review (which included searches from databases’ inception dates to May 2016) [42], and ran an updated search of AgeLine (EBSCOhost), Cumulative Index of Nursing and Allied Health Literature (CINAHL; EBSCOhost), MEDLINE (EBSCOhost), Scopus (Elsevier), Web of Science (Thomson Reuters), and NHS Economic Evaluation Database (Centre for Reviews and Dissemination); databases were last searched in September or November 2019. Grey literature searches were conducted of conference proceedings, websites, theses, and clinical trial registries. We conducted forward and backward citation searches on included studies, and a hand search was undertaken of the journal ‘Age and Ageing’. No language restrictions were placed on the search. The MEDLINE search strategy is provided as an example in an additional file (see Additional File 1).

Data collection

Data management

Search results were imported into a reference management software (Endnote™ online, Clarivate Analytics), and duplicates were removed. Screening and data extraction were supported by software (Covidence and Microsoft Excel). Data were analysed and synthesised in RevMan (version 5.3), NVivo QSR, and GRADE Pro GDT.

Study selection

Titles, abstracts, and full reports were screened independently by two review authors (LF plus AD, BK, CL, or OO) using an eligibility checklist. Disagreements were resolved through discussion and a third person.

Data extraction

For quantitative and qualitative studies, the study characteristics (funding, study design, interventions/phenomena of interest, population, outcome acquisition/methods, setting, public/patient involvement), risk of bias assessments, and outcome data, were collected independently in duplicate (AD, LF, BK, CL, KFS, CM, OO), using a data collection form and instructions (which was piloted on two studies). Disagreements were resolved through discussion and a third review author. Review authors were not involved in the assessment of primary research studies they had co-authored. Data from the economic studies were primarily collected by a health economist (JR), and checked by another review author (AD); data were collected on: research question, rationale, outcomes, perspective, time frame, costs, assumptions, and methods.

Risk of bias assessment and quality assessment

Studies were assessed independently in duplicate, using tools appropriate to each study design. The Cochrane Risk of Bias 2.0 tool (RoB 2.0 [52]) was used for randomised trials (with the extension for cluster trials where relevant [53]), the ROBINS-I (Risk Of Bias In Non-randomised Studies of Interventions) tool for non-randomised studies [54], and the Joanna Briggs Institute (JBI) critical appraisal checklist for qualitative studies [55]. Quantitative studies were assessed at the outcome level for our seven most prioritised outcomes (the two primary outcomes, and first five secondary outcomes). The credibility of individual findings extracted from qualitative studies were rated as ‘unequivocal’, ‘credible’, or ‘not supported’, according to the JBI criteria [55]. Problems with the quality of reporting of economic studies were assessed using the CHEERS checklist [56], and have been summarised as serious (< 50% items addressed), moderate (50 to 75% items addressed), and low (> 75% items addressed). Disagreements were resolved through discussion and involvement of a third review author if required.

Data analysis

Measures of treatment effect

We summarised outcomes using rate ratios (for injurious falls rate, falls rate, fracture rate, and hip fracture rate), risk ratios (for number of falls with injuries, number of fallers, number of head injuries), or odds ratios for rare outcomes (number of fractures, number of hip fractures). We used the reported estimates and 95% confidence intervals where available, or calculated them using the raw data if feasible and appropriate. Adverse events and process outcomes were summarised narratively in text and tables.

Unit of analysis issues

Three studies presented potential unit of analysis issues [13, 14, 57]. We avoided the double-counting of research participants in a factorial study and multi-intervention study by segregating the data across different comparisons/sub-groups. A cluster randomised trial had presented descriptive data useful for our secondary outcomes, for which we approximated the design effect based on wider literature [58,59,60], using sensitivity analyses to check our assumptions.

Dealing with missing data

One review author (LF) approached seven corresponding authors for missing and unclear data. Missing summary effect estimates were calculated where feasible from raw data. We conducted analyses based on the available data, and assessed the problem of missing or incomplete data from individual participants as part of our risk of bias judgements.

Assessment of reporting bias

We did not perform any statistical tests to assess for potential reporting biases due to insufficient studies; rather, we aimed to reduce the risk of publication bias affecting our review through a comprehensive search and communication with researchers in the field. We contacted corresponding authors for missing outcomes where we thought the data may have been feasibly collected. We assessed the potential for reporting bias as part of our GRADE assessments, and downgraded the quality of the evidence if reviewers agreed it was appropriate.

Data synthesis

Quantitative studies were synthesised in RevMan (version 5.3), with data presented separately for randomised trials and all studies combined. We pooled data using the generic inverse-variance method with a DerSimonian and Laird random effects model (assuming that intervention effects are likely to vary across studies), unless the outcome was rare, in which case we used Mantel-Haenszel analyses (fixed effect). Qualitative studies were synthesised in NVivo (version 12) using meta-aggregation to organise individual study findings into categories of similar meanings, which we subsequently pooled into synthesised findings. Economic studies were summarised narratively.

Assessment of heterogeneity

Heterogeneity was assessed through a combination of visual inspection of forest plots, along with consideration of tests for homogeneity (χ2 with statistical significance set at P < 0.10), and measures for inconsistency (I2) and heterogeneity (τ 2). Where feasible, we explored study design, setting, and flooring type via pre-specified subgroup analyses.

Sensitivity analyses

We undertook sensitivity analyses to explore the influence of risk of bias, choice of effect estimate, adjustment for clustering, use of unreported data, choice of analysis for rare events, and analysis decisions for the handling of the factorial study.

Confidence in cumulative evidence

We appraised the quality of the evidence across the included studies at the outcome level using GRADE for quantitative outcomes [61], and the GRADE CERQual approach for qualitative findings [62]. The final set of judgements were agreed via discussion between two review authors.

Triangulation of methods

We undertook a convergent segregated approach to mixed methods syntheses [47]; Each type of evidence (quantitative, qualitative, and economic) was analysed separately, prior to configuring the results in our overall discussion.

Changes from the protocol

We did not search the World Health Organisation Health Evidence Network as planned, due to a technical error with their server. Originally, we had planned to use one software (Covidence) for all of our data collection tasks; however, at the time of undertaking this review it did not support all of our needs so we supplemented it with another programme (Microsoft Excel), whilst maintaining our protocol of conducting the review processes independently in duplicate. We did not perform sub-group analyses on acuity of care as planned due to limited data. Our decisions for how to deal with a 2 × 2 factorial study and rare outcomes were not planned at the protocol stage, so we undertook sensitivity analyses to ascertain the robustness of these decisions. Our protocol used the language “patient bed-days”, however we have opted for the terminology “person bed-days” in this report, as whilst the calculation is the same, the phrase better suits both care home residents and hospital patients.


We screened 3444 records after removal of duplicates, of which 79 were assessed in full. Twenty-nine papers reporting 22 studies met our inclusion criteria (Fig. 1).

Fig. 1
figure 1

Flow diagram of study selection process

Characteristics of included studies

We identified 12 quantitative studies [12,13,14,15,16, 57, 63,64,65,66,67,68], ten of which contributed data to our pre-specified outcomes (3 to 7 studies per outcome). We analysed data from three randomised controlled trials (RCTs; 1 care home-based and 2 hospital-based studies) and seven observational studies (3 care home-based and 4 hospital-based), one specific to staff injuries (163 injuries) [68], and the others relating to 11,857 patient/resident falls (11 to 6641 falls per study). The interventions explored in these were carpet (N = 4 studies) [12, 13, 63, 66], sports floors (Tarket Omnisports Excel, N = 3) [14, 57, 68], novel floors (Kradal or SmartCells, N = 5) [15, 16, 57, 64, 68], and wooden sub-floors (N = 1) [13], with three studies exploring more than one flooring type [13, 57, 68]. The flooring industry funded the costs of flooring materials and installation in three of these studies but had no further involvement in the studies’ conduct [16, 57, 68], and an additional study received a grant from the flooring manufacturer [64].

Five qualitative studies were included [69,70,71,72,73], representing the views and experiences of 147 people, comprising hospital/hospice staff (N = 84) across a range of roles (managerial, doctors, nurses, allied health professions, domestic staff), senior managers of nursing homes (N = 27), hospital patients (N = 12), hospital visitors (N = 8), residents (N = 8), and long-term care nurses (N = 8). Three qualitative studies focussed on specific flooring systems (Tarkett Omnisports Excel = 1 study; Kradal = 2 studies) [69,70,71], one explored perspectives towards ‘purpose-designed compliant’ flooring [72], and another was around the built environment more broadly, within which the topic of carpets was discussed [73]. None of the qualitative studies were industry-funded.

We identified five economic studies [74,75,76,77,78]; two studies were based in Sweden, [75, 76] and the others were based in New Zealand [77], UK [78], and the US [74]. Four studies focussed on novel flooring (3 = Kradal, 1 = dual stiffness underlay) in care homes [74,75,76,77], and one focussed on a sports floor (Tarkett Omnisports Excel on concrete) in hospitals [78]. The control floors were generally not well described, but were ‘standard’ floor coverings such as vinyl or linoleum, and in two studies the sub-floor was known to be concrete [74, 78]. The characteristics of included studies are detailed in Table 1.

Table 1 Characteristics of included studies

Risk of bias and study quality

A summary of our risk of bias and quality assessments is provided in Fig. 2. Of the three randomised controlled trials, two were considered at low risk of bias [14, 16], and the other presented some concerns due to lack of information on allocation concealment and reporting of injuries (which raised the risk of bias to high for number of falls with injuries) [66]. The non-randomised studies were all judged to be at serious risk of bias across all outcomes, with the predominant issue being risk of confounding.

Fig. 2
figure 2

Risk of bias and quality assessments across key outcomes

Whilst most of the quality markers were adequately addressed in the qualitative studies, there were some issues with the quality of reporting, with none providing a detailed description of the underpinning philosophical perspective, and one lacked a clear description of the researchers’ cultural or theoretical positions [69]. One qualitative study was considered to have more serious shortcomings as it lacked a clear description of the analysis methods, and relied on personal recall to document data, meaning the report lacked representation of the participant voices [73]. This study however contributed minimal data to the synthesis, and its exclusion would not have changed the overall conclusions.

We judged there to be moderate issues in the quality of reporting of three economic studies [74, 75, 77]. More concerning than the quality of reporting, were the data used to populate the models, which varied widely. Only one, used new data from a randomised comparison [14, 78], with assumptions taken from the literature where data were very scarce [78]. Another used data from a small observational study, supplemented by best estimates from the literature made necessary by the small size of that study [75]. The other three were desktop exercises using available estimates mainly from the published literature [74, 76, 77].

Assessment of outcomes

A summary of findings for the seven prioritised quantitative outcomes is provided separately for hospitals (Table 2) and care homes (Table 3).

Table 2 Summary of findings for shock-absorbing flooring versus rigid flooring in hospitals
Table 3 Summary of findings for shock-absorbing flooring versus rigid flooring in care homes

Injurious falls rate per 1000 person days

RCT evidence provided no clear evidence to support shock-absorbing flooring use for reducing injurious falls rates (Rate Ratio [RaR] = 0.87, 95% CI 0.61 to 1.25, P = 0.46; 2 studies; I2 = 0%; Fig. 3) [14, 16]. Incorporating unpublished data from an observational study [57], maintained the possibility of the intervention making no difference, albeit the effect estimate shifted more in favour of the intervention (RaR 0.71, 95% CI 0.48 to 1.04, P = 0.08; 3 studies; Fig. 3). There was no evidence of a differential effect by study design, setting, or flooring type (novel and sports floors). When looked at in isolation, the hospital-based evidence (RCT and unpublished observational data) was indicative of a positive effect (RaR = 0.55, 95% CI 0.36 to 0.84, P = 0.006; 2 studies; I2 = 0%; very low-quality evidence; Fig. 3). Sensitivity analyses made no material difference to the conclusions.

Fig. 3
figure 3

Any shock-absorbing flooring versus rigid flooring for injurious falls rate per 1000 person days

Falls rate per 1000 person days

Pooled analyses of falls rates (for RCTs alone, and all study types combined) all incorporated the possibility that shock-absorbing flooring does not affect falls rates (based on novel and sports floors). One observational study of carpet versus vinyl, unsuitable for meta-analysis, was also non-significant [63]. Heterogeneity exists amongst the studies, with the confidence intervals of RCT evidence at low risk of bias additionally incorporating the possibility that shock-absorbing flooring may increase the rate of falls (RaR = 1.17, 95% CI 0.89 to 1.54, P = 0.27; 2 studies; I2 = 0%; Fig. 4), and observational studies at high risk of bias in favour of shock-absorbing floors (test for sub-group differences: Chi2 = 5.44, df = 1 (P = 0.02); I2 = 81.6%). There was no evidence of a differential effect by setting, or flooring type. Sensitivity analyses did not alter the conclusions.

Fig. 4
figure 4

Any shock-absorbing flooring versus rigid flooring for falls rate per 1000 person days

Number of falls with injuries

For this outcome we have treated the RCT data as if they are observational, since the outcome denominator is based on the observed number of falls and not the numbers of people randomised to each group. Overall (Fig. 5), the findings positively favour shock-absorbing flooring (RR = 0.69, 95% CI 0.52 to 0.90; P = 0.006), but are heterogeneous (Tau2 = 0.06; Chi2 = 14.71, df = 5 (P = 0.01); I2 = 66%). This heterogeneity can be largely explained by a retrospective cohort study at serious risk of bias comparing carpet versus vinyl [12], which counter-intuitively was more favourable than the studies on novel and sports floors [14,15,16, 57, 64]. There was no evidence of a differential effect by setting, or study design. Novel and sports floors produced similar findings, albeit the sports floor data were very imprecise (test for subgroup differences: Chi2 = 0.81, df = 1 (P = 0.37), I2 = 0%), but the study on carpet introduced heterogeneity (test for subgroup differences: Chi2 = 12.09, df = 2 (P = 0.002), I2 = 83.5%). The hospital data (RR = 0.39, 95% CI 0.15 to 1.02, I2 = 73%) were sensitive to the estimated intracluster correlation coefficient (ICC) of the cluster randomised trial [14], with a smaller ICC providing a more precise effect estimate in favour of the intervention floors (RR = 0.40, 95% CI 0.16 to 0.97; P = 0.04; I2 = 73%). In addition, the removal of the carpet study from the hospital subgroup resolved the heterogeneity and provided a more precise estimate in favour of shock-absorbing floors (RR = 0.64, 95% CI 0.44 to 0.93; P = 0.02; I2 = 0%).

Fig. 5
figure 5

Any shock-absorbing flooring versus rigid flooring for number falls resulting in injury

Number of fractures

Five studies reported on the outcome ‘any type of fracture’ [14, 16, 57, 64, 66]. We analysed fractures as a function of the number of participants, and the number falls to incorporate all of the evidence, however the latter may produce more biased effect estimates. The data were however too imprecise to detect with certainty whether shock-absorbing flooring reduces fracture risk (Fig. 6), as whilst the point estimates favour the intervention, the confidence intervals incorporate the possibility of no difference. We found no evidence for a differential effect between study designs, settings, or flooring types. Sensitivity analyses did not alter the bottom-line conclusions.

Fig. 6
figure 6

Any shock-absorbing flooring versus rigid flooring for number of fractures

Number of hip fractures

Four studies reported hip fracture outcomes [13, 14, 57, 66]. As for the number of fractures, Fig. 7 presents hip fracture data as a function of the number of participants and falls (here we have presented the data sub-grouped into flooring types). There was insufficient evidence to detect an effect related to overlay/underlay materials in hospitals, care homes, or both settings combined, and no indication of a differential effect by study design, setting, or flooring material. The data for wooden sub-floors was indicative of a beneficial effect however (OR = 0.59, 95% CI 0.45 to 0.78 (P = 0.008); serious risk of bias). Assuming that 4 out of 100 falls result in a hip fracture (based on the control arm of Simpson 2004 [13]), the effect estimate can be re-expressed to suggest that one less person will fracture their hip for every 63 falls (95% CI 47 to 118 falls) that occur on wooden as opposed to concrete sub-floors (very low-quality evidence). Our sensitivity analyses did not alter the bottom line findings, however not stratifying the factorial study by the other factor in that study removes the statistical heterogeneity from all of the analyses [13].

Fig. 7
figure 7

Any shock-absorbing flooring versus rigid flooring for number of hip fractures

Number of fallers

Three RCTs contributed data to this outcome [14, 16, 66]. Whilst the point estimate favours control floors, the confidence intervals incorporate the possibility that shock-absorbing flooring does not increase the risk of being a faller (RR = 1.28, 95% CI 0.73 to 2.25; P = 0.40; I2 = 46%; Fig. 8). There was no indication of a differential effect by setting, or flooring type. Sensitivity analyses did not alter the bottom-line findings, although removing the study at high risk of bias (on carpet) also removed the heterogeneity and produced an effect estimate more centred around the line of no effect (RR = 1.04, 95% CI 0.90 to 1.19 (P = 0.60); 2 studies on novel and sports floors).

Fig. 8
figure 8

Any shock-absorbing flooring versus rigid flooring for number of fallers

Number of adverse events (staff injuries)

Two RCTs collected data on staff injuries [14, 16], however since the unit of allocation in Mackey 2019 was the resident room [16], the data pertaining to staff injuries working within the same facility are more akin to a pre-post design and have not been published. One further observational study has been published [68]. Neither of the hospital-based studies were able to determine the size of the denominator population, as adverse events may have related to any events occurring on the participating wards involving staff based internally or externally to the wards, meaning accurate exposure time was not obtained. Overall, the data suggest that whilst initial concerns of working on a shock-absorbing floor maybe raised, there is very low-quality evidence to suggest that over longer periods of follow-up there may be no difference in staff injuries (Table 4).

Table 4 Adverse events associated with staff outcomes

Number of head injuries

Two studies reported the number of head injuries [16, 57], and we also incorporated personally communicated data pertaining to Gustavsson 2018 in a sensitivity analyses [15]. We analysed the data with both participants and falls as the denominator since it was not clear whether the number of events were independent or related to recurrent fallers, however this made negligible difference to the findings (Fig. 9). Whilst the confidence intervals incorporate a reduction in the number of head injuries, the data were too imprecise, and the possibility remains that shock-absorbing flooring makes no meaningful difference, when focussing on the RCT data alone (RR = 0.60, 95% CI = 0.24 to 1.51, P = 0.28) or both studies combined (RR = 0.52, 95% CI 0.24 to 1.12; P = 0.10; I2 = 0%). The two studies were statistically similar, although they were conducted in different settings and using different study designs (test for subgroup differences: Chi2 = 0.26, df = 1 (P = 0.61), I2 = 0%); there is no indication of a differential effect due to flooring type. A sensitivity analysis including unpublished data improves the precision of the effect estimate and indicates that shock-absorbing flooring may help reduce head injuries (RR = 0.55, 95% CI 0.31 to 0.97, P = 0.04; 3 studies; I2 = 0%). These additional data were from an observational study at high risk of bias and had not been adjusted for confounding. Other sensitivity analyses did not materially affect the findings.

Fig. 9
figure 9

Any shock-absorbing flooring versus rigid flooring for head injuries

Fractures and hip fractures per 1000 person-bed days

Whilst it was possible to derive fracture and hip fracture rates for three of the studies [14, 16, 57], the analyses did not provide any further information above and beyond the data we have already reported for number of fractures/hip fractures, and are problematic due to sparseness of data leading to imprecision.

Qualitative findings

Five qualitative studies generated 69 findings (61 unequivocal and 8 credible), creating ten categories, which generated three synthesised findings (Fig. 10).

Fig. 10
figure 10

Qualitative synthesis flow chart

Qualitative finding 1: We have moderate confidence that shock-absorbing flooring is viewed by many as a potential solution to help protect people from fall-related injuries, with a potential side effect of improving environmental comfort.

Participants acknowledged that falls were a problem in older age, and that shock-absorbing flooring is a potential solution to help prevent injurious falls. Senior managers in particular expressed uncertainty around the effectiveness of floors and wanted to see further evidence; however, some staff held strong beliefs about the value of intervention floors for preventing injuries. These beliefs influenced behaviours in terms of where patients were placed, and what other injury-prevention interventions were used, and provided staff with reassurance that a ‘safety net’ was in place. Benefits were discussed in terms of improved staff morale (because they perceived that they were better able to prevent injuries), noise reduction, and some conflicted findings around improved comfort when walking and kneeling. Hospital staff, patients, and visitors found sports flooring more comfortable underfoot, whereas some care home staff debated whether the novel shock-absorbing floor they were exposed to, may be more demanding to walk on, contributing to some initial subsiding muscle soreness. Mixed views were expressed around colour and pattern choices, emphasising the need to consider the influence of a new floor on the ambient environment.

Staff member, hospital: because we’ve got that floor we know it’s a special floor and we, and we put our vulnerable patients in that bay because we know if they fall and they fall on that floor then they’re gonna be protected more than they would if they fell in another bay [69].

Qualitative finding 2: We have high confidence that changing a floor has consequences for the wider system (e.g. affecting the ease of moving equipment), potentially leading to further adaptations and adjustments in behaviours, attitudes, equipment, processes, and staffing.

This finding draws together the potential consequences (whether actual or perceived) that implementing a new shock-absorbing floor can have, related to push and pull challenges, walking and mobilising, cleaning and maintenance, and the introduction of a ‘novelty factor’ in to the environment. The perceptions people held contributed to adaptations in people’s behaviours and attitudes, for example, with regards to processes (e.g. where to place the trolley on medication rounds, where to rehabilitate patients), and staffing (e.g. rotating staff members more).

Staff member, hospital: I’ve actually hurt my neck today transferring a patient using a turntable um, the patient was stood on the turntable and when I went to turn it, it wouldn’t turn at all um, and that’s not usual for a turntable and it wasn’t anything that the patient or myself or my assistant were doing, it was the floor that was stopping the turntable moving… I actually hurt my neck on it because the patient didn’t move and I did move [69].

Qualitative finding 3: We have moderate confidence that installation may be an initial concern but can be effectively managed; however, cost and funding considerations need to extend beyond the initial purchase and installation, to consider potential adaptations in staffing/processes/equipment, and potential cost-savings from fall-related injury prevention (should the floor be effective).

This finding encapsulated discussions on the installation process, which typically went smoothly even when installation was conducted as a retrofit, which was of concern to some along with the management of thresholds. Upfront costs associated with installation have budgetary implications with funding mechanisms likely to vary by setting, context, and whether it is for a new build or retrofit. Senior managers were cognisant of potential extra costs associated with obtaining compatible equipment for use with the floor, and staff training, as well as potential cost-savings.

Senior manager, care home: You’d have to look at the flooring [.. .] at where it’s going and then if you have to look at the motorized lifts and [.. .] different equipment to accommodate the flooring. [.. .] And training for the staff on proper body mechanics. [.. .] it’s not just how much the flooring costs [72].

Economic outcomes

Five studies contributed economic data [74,75,76,77,78], four of which were very low quality [74,75,76,77]. Whilst there was heterogeneity between the floors, settings, and population groups assessed, the assumptions made in the poorer quality studies may have been unduly optimistic. Three of these found that shock-absorbent floors dominated standard floors in that costs were less and outcomes improved [74, 76, 77], and one estimated that shock-absorbing floors increased both costs and quality-adjusted life years (QALYs) but at a cost per increased QALY well above the accepted threshold level [75]. The QALY gains in these studies were a result of assuming relatively large QALY losses due to hip fracture. Only the higher quality study collected data on quality of life [78]. This study found reduced QALYs, albeit with reduced costs, which despite a favourable incremental cost effectiveness ratio, was noted to not likely be a result leading to implementation. The reduced QALYs in this study were based on the assumption that shock-absorbing flooring increases falls risk; a sensitivity analysis demonstrated that if shock-absorbing flooring does not increase the number of fallers yet reduces the number of injurious falls, the intervention floor would become dominant.

Process outcomes

Whilst no process evaluations were identified, the qualitative outcomes captured process issues around installation, maintenance and ease of use. Here we report on additional information provided by the quantitative studies. One study described a 20–30 cm split seam in the new floor attributed to welding at installation which was subsequently repaired [14]. The types of floors selected in studies influenced where they were placed as some flooring types were unsuitable for wet areas. As a minimum, floors were placed in the bedded areas, and in care homes the coverage extended to other living areas (Table 5). We were able to assess the protection offered in terms of the number of falls that occurred in the target areas in three studies, to find that upwards of 75% of all falls occurred on the intervention floors for participants assigned to the intervention group, when at least the bedded areas were covered. Two quantitative hospital-based studies reported impacts on the working environment [14, 57], citing increased effort required to move wheeled equipment. One of these studies also highlighted changes to staffing to support manual handling, with one of the four intervention sites increasing staffing from six to seven staff members during the 07:00–15:00 shift, and another site altering the shift patterns (maintaining the overall staffing levels) to increase cover on the night shift [69].

Table 5 Floor coverage and proportion of falls occurring on target areas with intervention


The findings from the different types of evidence (quantitative, qualitative, and economic) included in this review, were largely complementary of each other and focussed on different aspects of our research question; however, there were some exceptions. The qualitative evidence suggests that many people view shock-absorbing flooring as a potential solution for reducing injurious falls, and whilst the limited robust quantitative data did not confirm this to be true, very low-quality quantitative data indicates shock-absorbing flooring may have a positive effect. We cannot discern from this whether the views held by those utilising the floors are contributing to bias in the very low-quality quantitative evidence, or if the qualitative evidence is merely reflecting some truth identified by the low-quality quantitative evidence. There were no qualitative data linked to the non-significant trial contributing the more robust quantitative evidence, which may further explain this contradiction. The qualitative data additionally highlighted that senior managers were aware of the potential for additional costs associated with shock-absorbing flooring, in relation to workplace adaptations (e.g. staffing levels, training, equipment upgrades), however to date these costs have not been considered in economic evaluations.

Systematic reviews on flooring materials are sparse, with Cochrane reviews on falls prevention [9], and hospital environments [80], excluding or not fully covering the studies on shock-absorbing flooring. There has been a scoping review of shock-absorbing flooring [42], and a review on floor finishes with a facility management focus [11]; however, these were descriptive rather than analytical, and did not incorporate a risk of bias or quality assessment, nor include all of the studies we identified. The scoping review did however incorporate a broader range of literature [42], including laboratory-based and biomechanical studies exploring impact absorption, gait, and balance [24,25,26,27,28,29,30,31,32,33, 35, 48, 81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101].

We found one high quality study indicating that a novel shock-absorbing underlay was no more effective than rigid flooring in care homes [16], and very low-quality evidence that shock-absorbing flooring may reduce fall-related injuries. Laboratory studies typically indicate the promise that shock-absorbing flooring holds in terms of impact absorption, with the same underlay that was found to produce null clinical effects in the present review [16], demonstrated to attenuate peak force by up to 33.7% to the hip [25], and 80% to the head [27], in simulated laboratory falls. This disconnect may relate to: (i) the underlying assumptions of laboratory-based research (e.g. the biofidelity of test systems, impacts simulated and assumed to be involved in injuries); (ii) co-interventions or other setting or fall characteristics that may negate the power of a clinical study to detect a change attributable to flooring; or (iii) the susceptibility of study populations to low-impact trauma such that the impact attenuation achieved remains insufficient. The clinical evidence we found in favour of shock-absorbing flooring, which aligns with the indications of laboratory evidence, was of very low quality, meaning that it is very uncertain and further research is likely to improve our understanding.

Push and pull tasks have been explored in biomechanical studies, highlighting the increased forces required to move wheeled equipment [36, 102, 103]. The biomechanical literature complements our findings, and highlights the important interactions between equipment types, flooring materials, and pushing forces required, indicating the potential for risk mitigation strategies to help prevent adverse events.

A further concern related to shock-absorbing flooring is the potential for it to lead to instability and increase falls risk [26]. We found very low-quality evidence in hospitals that the rate of falls was not increased with shock-absorbing flooring, and moderate- and high-quality evidence in care homes that falls rates and faller risk were not affected by SmartCells underlay. These findings align with biomechanical evidence (often conducted with healthy adults), which supports that individuals can maintain their balance on carpet [28, 86, 87], and novel shock-absorbing floors [25, 26, 28, 30, 104, 105]. Compliant surfaces have been contraindicated however when sensory input (such as visual cues) is affected [24, 86, 94], and stroke patients have been shown to find carpet more challenging than parquetry [31]. Other biomechanical research on hospital inpatients found no difference in their ability to perform the timed-up-and-go test on novel, sports, and rigid flooring types [105]. The current direct and indirect evidence appears promising in suggesting that falls are not adversely increased on shock-absorbing floors, however the evidence is imprecise in hospital settings, and biomechanical evidence in clinical populations is sparse.


There is high-quality evidence that a novel shock-absorbing underlay produces similar injury and falls rates to a rigid plywood underlay, with vinyl overlays and concrete sub-floors in care homes. When incorporating observational studies, we found very low-quality evidence that shock-absorbing flooring may reduce the number of falls resulting in injury in care homes. There is also very low-quality evidence that shock-absorbing flooring use in hospitals may reduce injuries without increasing the rate of falls. Data on fractures and head injuries were generally too imprecise to determine effectiveness in care homes and hospitals; however, one observational study at high risk of bias indicated that fewer hip fractures were likely to occur on wooden sub-floors compared to concrete sub-floors in care homes. Including unadjusted unpublished observational data on head injuries indicated that shock-absorbing flooring might reduce head injuries; however, these data are of very low quality. Whilst some adverse events were described, there is very low-quality observational evidence that novel and sports floors do not result in more staff injuries in up to two years follow-up. The qualitative data is indicative that there may have been under-reporting of adverse events in the trial data [69]. Staff did report increased effort required to manoeuvre wheeled equipment (in both quantitative and qualitative studies), which led to changes in the workplace; it is unclear whether the lack of observed influence of shock-absorbing flooring on staff adverse events is despite or because of these workplace adaptations, or due to flaws in the studies collecting data on these outcomes.

Fall-related injuries remain a significant problem for care settings [2, 3]. The present systematic review summarises evidence associated with shock-absorbing flooring, which remains a potential solution albeit the research in favour of shock-absorbing flooring has limitations and is therefore very uncertain; this has led to the following prioritised recommendations for research:

  1. 1)

    To establish a clearly defined core outcome set for flooring studies, which includes recommendations for measurement, analysis, and reporting.

  2. 2)

    Research questions lending themselves to observational designs need to address the above core outcome set, and comprehensively deal with potential confounding. Other questions (particularly on new flooring interventions) lend themselves to pragmatic randomised controlled trials, of which there are a paucity.

  3. 3)

    The dearth of robust research on the effectiveness of shock-absorbing flooring in hospital settings should be addressed.

  4. 4)

    Studies should plan for workplace adaptations within the study design, for example through process evaluations and risk management plans to better mitigate, manage and evaluate risks to staff. Further research and innovation is also required to identify how best to adapt the workplace to shock-absorbing flooring.

  5. 5)

    High quality economic evidence is required that provides improved specifications of the alternatives evaluated, distinguishes falls by severity and type, specifies the processes by which reductions in types of falls are expected to improve health, uses appropriate time frames, provides greater details to enable different definitions of costs to be used, and considers the costs of workplace adaptations.

  6. 6)

    With the uncertainty surrounding current flooring solutions, research and innovation is required to establish the specifications for improved products to support fall-related injury prevention in care settings.

Availability of data and materials

The datasets supporting the conclusions of this article are available in the full report and its additional files (published with the Health Technology Assessment [43]). Project files are available on the Open Science Framework ( Any additional data can be obtained from the corresponding author on request.



Confidence in the Evidence from Reviews of Qualitative research


Confidence Interval


Cumulative Index of Nursing and Allied Health Literature


Grading of Recommendations, Assessment, Development and Evaluations


Joanna Briggs Institute


National Health Service


National Institute for Health Research


Patient and Public Involvement


Quality-adjusted Life Years


Randomised Controlled Trial


Risk of Bias


Risk Of Bias In Non-randomised Studies of Interventions


Rate Ratio


Risk Ratio


United States Dollars


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This review was developed and delivered through the support and guidance of our Advisory Board members: Nadra Ahmed (National Care Association, UK); Margaret Bell (Public Involvement Member, UK); Liz Burden (Public Involvement Member, UK); Dr. Alison Cracknell (Leeds Teaching Hospitals NHS Trust, UK); Kirsten Farrell-Savage (University of Portsmouth, UK); Olanrewaju Okunribido (Health & Safety Executive, UK); Jonathan Stewart (Health Estates and Facilities Management Association [HEFMA], UK); Joleen Tobias (Public Involvement Member, UK); Julie Windsor (NHS England/Improvement, UK); Dr. Anna Winfield (Leeds Teaching Hospitals NHS Trust, UK).

Our public involvement members (Margaret Bell, Liz Burden, and Joleen Tobias) additionally supported the protocol development, communication of the risk of bias assessments and GRADE assessments, development of the plain English summary, and dissemination activities. Olanrewaju Okunribido and Kirtsen Farrell-Savage additionally supported data acquisition.

We would like to thank Dr. Ngianga Li Kandala for his statistical support and advice, and Dr. H. Carl Hanger and Dr. Johanna Gustavsson for their co-operation, time, and generous supply of unpublished data for incorporation into this review.


This report presents independent research funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme. The views expressed in this publication are those of the authors and not necessarily those of the NHS, the National Institute for Health Research or the Department of Health and Social Care. The Health & Safety Executive supported 10 days of Olanrewaju Okunribido’s time in kind on this project.

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AD contributed to: the conception and design of the review; acquisition, analysis, and interpretation of data; drafting and critically revising the manuscript for important intellectual content; final approval; and agrees to be accountable for all aspects of the work. LF and JR contributed to: the design of the review; acquisition, analysis, and interpretation of data; critically revising the manuscript for important intellectual content; final approval; and agrees to be accountable for all aspects of the work. BK and DM contributed to: the conception and design of the review; acquisition and interpretation of data; critically revising the manuscript for important intellectual content; final approval; and agrees to be accountable for all aspects of the work. CL contributed to: the conception and design of the review; acquisition of data; critically revising the manuscript for important intellectual content; final approval; and agrees to be accountable for all aspects of the work. CM contributed to: acquisition, analysis, and interpretation of data; critically revising the manuscript for important intellectual content; final approval; and agrees to be accountable for all aspects of the work. AL contributed to: the conception and design of the review; critically revising the manuscript for important intellectual content; final approval; and agrees to be accountable for all aspects of the work.

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Correspondence to Amy Drahota.

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Competing interests

AD and BK collaborated with the Health & Safety Laboratory (2018–2020) on some unfunded academic research using a new testing procedure to assess the shock-absorbency of various floor coverings; Five flooring manufacturers delivered free samples to use in the project. AD and BK have no stake in any of these companies. In 2015, AD was involved in a collaborative funding application with Polyflor; The application was short-listed but unsuccessful. AD has no stake in this company. AL reports grants from SofSurfaces Inc., grants and personal fees from SorbaShock LLC, grants and personal fees from Viconic Sporting, outside the submitted work. AL was a member of an ASTM Work Group (WK38804) whose Technical Contact is the President of SATech. SATech, Viconic Sporting, and Mannington Mills have donated flooring materials to AL’s laboratory that have formed the basis of several studies examining the biomechanical effectiveness of compliant flooring (i.e. safety flooring). AL has never had (nor does he currently have) any financial links to these companies. CL is employed at the Canadian Agency for Drugs and Technologies in Health (CADTH) outside of the submitted work. AD, DM, CL, and AL authored original research papers that were included in this review. JR is a member of the NIHR’s HTA/EME editorial board (0.2 whole time equivalent). CM declares that he has no competing interests.

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Drahota, A., Felix, L.M., Raftery, J. et al. The SAFEST review: a mixed methods systematic review of shock-absorbing flooring for fall-related injury prevention. BMC Geriatr 22, 32 (2022).

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  • Accidental falls
  • Bone
  • Floors and floor coverings
  • Fractures, hospitals
  • Long-term care