Serious stair injuries can be prevented by improved stair design

doi:10.1016/S0003-6870(00)00049-1

Applied Ergonomics

Volume 32, Issue 2, April 2001, Pages 135-139

https://doi.org/10.1016/S0003-6870(00)00049-1 Get rights and content

Abstract

An estimated 2.5 million injuries, and a further 4000 deaths in the UK in 1995 were due to home accidents. About 230,000 of these injuries and 497 deaths resulted from falls on stairs. When exposure is taken into account, stairs are one of the most hazardous locations in buildings. Of these falls, those where the person falls forward are most likely to cause severe injuries. One aspect of stair design, the “going” (the horizontal distance between two consecutive nosings) can be changed to decrease the potential number of serious trip accidents. Builders should therefore be encouraged to build stairs with larger goings.

Introduction

In the UK, every year there are an estimated 2.5 million home accidents serious enough to cause the victim to attend a hospital Accident and Emergency (A&E) unit (Consumer Safety Unit DTI, 1997). There are a further 4000 deaths resulting from home accidents. An estimated 230,000 of these accidents and nearly 500 of the fatalities were the result of falls on stairs. Taking into account the amount of time people spend on stairs, this makes stairs the most dangerous component of any home. This paper considers the seriousness of one particular stair accident scenario and what could be done to reduce the number of accidents that might occur as a result of this hazard.

Section snippets

Types of stair accident

There are at least three major reasons for stair accidents: user behaviour, maintenance and design. User behaviour accidents might include: tripping over objects placed on steps (roller skates or the cat, for example), running up or down the stairs, missing steps or taking two or three steps at a time. They could even include playing or fighting on stairs or just being distracted by some other event causing that momentary lack of attention. Such accidents are difficult to control and hence will

Stair terminology and geometry

Stair geometry can be described by the terms “rise”, “going” and “pitch”, (see Fig. 1.) The rise, the vertical distance between two consecutive treads or between a tread and a landing, is easily determined from the floor-to-floor height where the stair is to be situated. Since it is good design to have equally sized steps the floor-to-floor height should be an exact multiple of the rise. For example with a floor-to-floor height of 2.6 m, typical in British dwellings, the rise could be 260, 236,

The stair gait

People walk up and down stairs in a manner that is very different to walking on the level; a full description of the normal stair gait is given by Templer (1992) and is summarised as follows. In descent, where the accidents tend to be more serious, the leading foot swings over two nosings (of the tread the leading foot was on and the tread the rear foot is now on) and stops over the tread below; this is known as the swing phase. As this leading foot starts its descent the heel of the rear foot

Hazards associated with the stair gait

On ascent, the accidents tend to be less severe in nature (Templer, 1992). This is because the centre of gravity of the user is slightly forward, so that most falls are relatively small and towards the higher steps. The greatest risks, when considering the gait, are during the swing phase. As the rear foot passes over two nosings, there is a high risk of tripping; this is particularly heightened if there is a large variation in rise values along the flight. Another risk situation in ascent is

Can these injuries be prevented?

These accidents, and hence the injuries that result from them, are to a large extent preventable by making the stair goings larger than the feet of the users. Where the stairs are unfamiliar to the users, and when crowds might be using the stair at the same time, this safety measure is already applied. Under the present guidance (Department of the Environment and the Welsh Office, 1992; British Standards Institute, 1984) the going in these situations should be a minimum of 280 mm. This compares

The costs and the benefits

What will it cost builders to install these larger stairs? The maximum possible cost to the domestic property builder would be a loss of floor area of approximately 0.6 m² for a 900 mm wide stair, i.e., 0.3 m² downstairs and a 0.3 m² hole upstairs. Some of this lost floor area could, however, be recovered elsewhere, for example, with increased under stair storage, or adequate space for a downstairs WC. Rearrangement of the internal space could therefore make these changes negligible, or even

References (6)

British Standards Institute, 1984. BS5395: Part 1: 1977: Stairs, Ladders and Walkways: Code for the Design of Straight...
Consumer Safety Unit, DTI, 1997. Home Accident Surveillance System 1995: 19th Annual Report. Department of Trade and...
Department of the Environment and The Welsh Office, 1992. The Building Regulations 1991 Approved Document K: Stairs,...

There are more references available in the full text version of this article.

Cited by (86)

Perceptual-motor recalibration is intact in older adults
2023, Human Movement Science
From an ecological perspective, perceptual-motor recalibration should be a robust and adaptable process, but there are suggestions that older adults may recalibrate slower. Therefore, this study investigated the age-related temporal effects in perceptual-motor recalibration after motor disturbances. In three experiments, we disturbed young and older adults' perception-action by fitting weights around their ankles and asking them to climb stairs or cross obstacles repeatedly. In Experiment 1, participants (n = 26) climbed stairs with different ankle weights. An innovative methodology was applied, identifying the timeline of recalibration as the point where a stable movement pattern emerged. Experiment 1 showed that older adults recalibrated slower than young adults in lighter (but not heavier) weight conditions. In Experiment 2, participants (n = 24) crossed obstacles with different ankle weights. Results showed that older adults recalibrated faster than young adults. Finally, in Experiment 3, participants (n = 24) crossed obstacles of unpredictable and varying heights with heavy ankle weights. Again, results showed that older adults recalibrated faster than young adults. Taken together these results show that although older adults had reduced muscle strength and flexibility, they recalibrated quickly, especially when the task was more challenging.
The effects of Müller-Lyer illusion on toe clearance height in stair ascent
2022, Gait and Posture
The appearance of a stair can impact the safe negotiation of stair climbing. Increasing toe clearance height is a common strategy for reducing the risk of tripping when stepping onto a raised surface.
Can the Müller-Lyer illusion cause people to increase their toe clearance height when walking over a stair?
Indoors, 15 healthy individuals (9 women and 6 men) walked up a 3-step staircase with each step 60 cm wide, 18 cm tall, and 30.5 cm deep. Outdoors, 253 people walked up a 2-step staircase with each step 6 m wide, 15 cm tall, and 38 cm deep. Four visual conditions were displayed at both the indoor and outdoor locations: fins out, fins in, line, and control.
While the fins out stairs were perceived taller than all the other displayed stair conditions, the toe clearance height was not different between display conditions when tested indoors. However, toe clearance height was greater in the fins out condition when compared to all other conditions for the outdoor stairs location.
In the natural environment when walkers were oblivious to themselves being filmed and not having any knowledge of the task demand, the Müller-Lyer illusion significantly impacted their toe clearance height.
Underlying mechanisms of fall risk on stairs with inconsistent going size
2022, Applied Ergonomics
Citation Excerpt :
Large rises (height of each step) and small goings (tread) (Templer, 1992) increase muscular force demand, further decrease foot clearances and the amount of foot placed on each step (Di Giulio et al., 2020; Roys, 2013; Templer, 1992), increasing the risk of a fall. Thus, stair dimensions are known to be associated with the risk of falling (Roys, 2001, 2013; Templer, 1992). UK building regulations specify going dimensions should be between 220 and 400 mm in private dwellings and be greater than 250 mm for public stairs.
Serious falls occur frequently on stairs with inconsistent dimensions. Inconsistent smaller goings are thought to reduce user's foot clearances and foot contact lengths since individuals do not detect and alter their behaviour prior to the inconsistency, increasing the risk of a trip, heel-catch or over-step and potential slip on the stairs. So far, these mechanisms for a stair fall remain theoretical only. The aim of this paper was to identify the underlying mechanisms by which steps with inconsistent going size increase the risk of falls. For this study twenty-seven younger adults (24 ± 3 y, 1.74 ± 0.09 m, 71.41 ± 11.04 kg) and thirty-three older adults (70 ± 4 y, 1.68 ± 0.08 m, 67.90 ± 14.10 kg) ascended and descended a seven-step instrumented staircase in two conditions: 1) consistent dimensions with 200 mm risers and 250 mm goings and 2) inconsistent going dimensions where the going of the third step was reduced by 10 mm, and consequently the going of the second step was larger by 10 mm. Five repeated trials on the inconsistent stairs were performed to assess if there was an adaptation effect after first exposure.
In descent in the first inconsistent trial, foot contact lengths were not significantly different between conditions for the younger and older adults on the inconsistently shorter step (∼1%, p = .121). Foot trajectories were pulled further back in the last 22% of swing before contact (p = .025), contradicting previous expectations. Younger adults then had reduced clearances over the next step (∼5 mm, p = .027), which was inconsistently longer, increasing the risk of a heel-catch, whereas foot clearances for older adults were not different. With repeated inconsistent trials the foot contact length of older adults reduced on the shorter step (p = .024).
In ascent, in the first inconsistent trial, interaction effects were detected between groups and conditions on three steps: the inconsistently longer step (p = .003), the shorter step (p = .004), the next step (p = .006), as well as on the walkway (p = .048). Older adults positioned themselves further away from the stairs on the walkway compared to younger adults and then had a reduced foot contact length on the inconsistently shorter step (∼2.8%, p = .026), increasing the chances of under-stepping and slipping off the shorter step. Whereas younger adults were positioned closer to the stairs on the walkway, had increased foot contact lengths on the inconsistently longer step and contact lengths that were not different on the inconsistently shorter step. With repeated inconsistent trials, foot contact lengths were reduced on the longer step (p = .006) and then on the shorter step (p = .018).
These findings contradict previous assumptions that individuals do not adapt to inconsistent goings on stairs. In descent on the first trial, both groups adjusted their stepping behaviour late in the swing prior to contact with the first inconsistent step. In ascent younger adults made changes to their position and stepping behaviour before stepping on the stairs. These behaviours to mitigate the risk of the inconsistent step, did not persist in the repeat trials. Future investigations should establish the magnitude at which inconsistencies are detectable and can be acted upon and should include a wider range of individuals. This type of research could help inform future initiatives to prevent serious stair falls.
Staircase design for health monitoring in elderly people
2021, Journal of Building Engineering
The need for early detection and intervention for age-related health deterioration via home-based health monitoring systems is growing with global population aging. Health deterioration is typically evaluated using questionnaires, but obtaining frequent responses is difficult. Although stair walking involving a high physical load is suitable for assessing health deterioration, uniform assessment using home-based systems is difficult because different stair designs result in different movements. There is currently insufficient research on differences in evaluation performance between different stair designs. The current study aimed to develop an objective index to assess difficulties in activities of daily living (ADLs) as an indicator of health deterioration by observing stair walking, and to investigate the effects of stair dimensions on the relationship between the index and health deterioration. We hypothesized that knee joint positions during stair ascent would be associated with health deterioration, and developed the “Stepping in Level” index, reflecting the knee joint position when stepping in, obtained using a markerless depth information-based system. Seventy elderly people ascended two types of stairs (steep: 33.7°; shallow: 28.2°) and completed a questionnaire regarding ADL difficulty. We used a generalized linear mixed model to investigate the ability of “Stepping in Level” to explain ADL difficulty. The results revealed that “Stepping in Level” was able to explain ADL difficulty, and steep stairs were more suitable than shallow stairs for assessment. Our system enables daily assessment of difficulty in ADLs and detection of subtle changes in daily life. The current findings could inform design guidelines for health monitoring.
Determining the effect of stair nosing shape on foot trajectory during stair ambulation in healthy and post-stroke individuals
2021, Applied Ergonomics
Stair design can influence the risk of stair falls. Stair nosings are intended to provide greater foot accommodation, although to date little is known about how the nosing shape can affect foot trajectory during stair ambulation. This study investigates the impact of different nosing shapes (round, square, tapered, and no nosing) on foot clearance and overhang measures during stair ascent and descent among healthy and post-stroke older adults. Slower cadence in ascent and descent, and greater foot overhang during descent highlighted the increased risk of stair falls for persons with chronic stroke. For both healthy and post-stroke participants, the tapered and round nosing shapes resulted in the largest horizontal foot clearance, and smallest foot overhang, respectively. However, given the greater step-to-step variability detected with round nosings, the tapered nosing presents as the safest choice among all evaluated designs. The results of this work can be used to inform architectural and accessible design standards for a safer built environment.
Negotiating stairs with an inconsistent riser: Implications for stepping safety
2020, Applied Ergonomics
Stairs are associated with falls, especially when step dimensions are inconsistent. However, the mechanisms by which inconsistencies cause this higher risk are mostly theoretical. In this experimental study we quantified the effect of inconsistent rise heights on biomechanical measurements of stepping safety from younger (n = 26) and older adults (n = 33). In ascent, both groups decreased foot clearance (~9 mm) over the inconsistently higher step (F(1,56) = 48.4, p < 0.001). In descent, they reduced foot contact length on the higher step by 3% (F(1,56) = 9.1, p < 0.01). Reduced clearance may result in a toe-catch potentially leading to a trip, while reduced foot contact lengths increase the risk of overstepping which may also lead to a fall. These effects occurred because participants did not alter their foot trajectories, indicating they either did not detect or were not able to adjust to the inconsistent rise, increasing the likelihood of a fall. Consistent stair construction is vital, and existing inconsistencies should be identified and safety interventions developed.

View all citing articles on Scopus

View full text