Slip and fall risk among firefighters in relation to balance, muscular capacities and age
Introduction
In firefighting and rescue operations work conditions are unpredictable and rapidly changing. Surfaces can be slippery and passages narrow and smoky or totally dark. Firefighters work frequently on roofs and with ladders, and they smoke-dive (i.e., extinguish a fire and rescue victims in environment where is smoke and combustion gases), which also requires good balance and muscular capacities (Lusa et al., 1994). Besides of smoke-diving, also the other work tasks of firefighters often necessitate the use of fire-protective equipment, including fire-protective clothing and a self-contained breathing apparatus (SCBA). The SCBA increases strain on the postural control system by increasing postural sway, especially, when postural muscles are fatigued (Kincl et al., 2002). Furthermore, a large amount, about 30%, of work-related accidents among professional firefighters in Finland are due to slips or falls at the same level (Statistics Finland, 1996–2001). The proportion of slips and falls at the same level is lower (23%) among the working population in Finland (Statistics Finland, 2002). Compared with younger workers, workers over 45 years of age were reported to have a greater proportion of slip-, trip- and fall-related injuries (Kemmlert and Lundholm, 2001, Statistics Finland, 2002).
The heel contact phase in early stance and the push-off phase during late stance are considered the most critical phases in locomotion when a slip and fall may occur (Perkins, 1978, Redfern et al., 2001, Strandberg and Lanshammar, 1981). For measuring forward slipping after the heel contact, slip distances during walking are used as indicators of slipping and falling hazards or as a discriminating factor between a slip recovery and likely falling (Brady et al., 2000, Grönqvist et al., 1993, Strandberg and Lanshammar, 1981). Longer slip distances are associated with an increased risk of falling (Brady et al., 2000, Grönqvist et al., 1993, Strandberg and Lanshammar, 1981). The nature of slipping and falling events is complex. Therefore, different objective, subjective and combined approaches are needed and used for studying individual risks of slips and falls in a laboratory (Brady et al., 2000, Grönqvist et al., 1993, Grönqvist et al., 2001a, Grönqvist et al., 2001b, Hirvonen et al., 1994, Strandberg and Lanshammar, 1981, You et al., 2001). During the slipping event, however, the variable that, according to current knowledge, best describes the probable outcome of a foot slide is the slip distance (Brady et al., 2000). The critical slip distance between an avoidable and unavoidable fall is reported to be in the range 5–22 cm (Brady et al., 2000, Grönqvist et al., 1993, Grönqvist et al., 1999, Strandberg and Lanshammar, 1981). A slip distance less than a few centimeteres may not be perceived by a person as a slippery condition, while a slip distance over 5 cm may cause falling accidents (Grönqvist, 1995).
The risk exposure to slipping and falling depends primarily on poor friction between footwear and underfoot surfaces (Grönqvist et al., 2001b, Hanson et al., 1999). The friction demand, in terms of the peak required friction coefficient, has been reported to vary between 0.17 and 0.22 for normal walking on level surfaces (Redfern et al., 2001). The magnitude of a given risk exposure depends on several extrinsic and intrinsic factors, for example, lighting, an individual’s perception and cognition of the hazards and the ability to regain balance (Grönqvist et al., 2001b). Lockhart et al. (2000) showed that older people experience as many slips as middle-aged and younger people, but their horizontal heel velocities at heel contact are higher and the slip distances longer, resulting in a higher frequency of falls. The ability to recover successfully from a slip may be affected by a degradation of lower-legs muscle strength, sensory function and balance (Lockhart et al., 2000). In epidemiological studies, impaired balance and muscle strength are significant risk factors for falling among older people (Lord and Clark, 1996, Stalenhoef et al., 2002). Although the importance of balance, muscular abilities and age in the risk of slipping and falling is recognized, still little is known about how these factors are associated with biomechanical parameters of slip and fall risk. The aim of this study was to investigate the slip and fall risk in walking experiments with firefighters who wore fire-protective equipment and to determine the associations of balance, muscular capacities and age with the risk of slipping.
Section snippets
Subjects
The subjects were a subgroup (n = 29) of 69 male firefighters who participated in a 3-year follow-up study on the health and physical and mental capacity of Finnish professional firefighters (Punakallio et al., 1999). Altogether 36 of 69 firefighters in three age groups (33–38, 43–48 and 53–56 years) were asked to volunteer for this study. First 12 randomly selected subjects in each age group were asked to volunteer. Six firefighters over 50 years of age were excluded because they had had
Results
When the path was spread with water and detergent, two subjects in the older age group slipped 4 cm, and the sliding movement and balance was well controlled. After the track was made slippery with glycerol, every subject slipped in the tests at both walking cadences. Half of the subjects slipped over 5 cm in the test (Table 2). The average values of the slip distances were 9.7 ± 9.1 cm (100 steps/min) and 15.6 ± 18.2 cm (120 steps/min) in the 33-to-38-year age group and 10.8 ± 15.3 cm and 18.0 ± 18.6 cm,
Discussion
The main findings of this study were that fast and controlled performance in the dynamic stability test was related to smaller (slip distance <5 cm) risk of slipping and falling, but the associations between muscular capacities and the risk of slipping were not significant. These associations were the same for both age groups. The older firefighters tended to have longer and more serious slips than the younger ones, but the difference was not statistically significant. Furthermore, half of the
Conclusion
The younger and older firefighters of our study experienced as many slips, and half of both groups experienced over 5 cm foot slides considered to increase the risk of an unavoidable fall. Older firefighters, however, tended to have longer slip distances than the younger ones at a faster walking speed in particular. The firefighters whose slip distance was over 5 cm performed significantly poorer in the dynamic stability test as well, whereas associations between muscular capacity and the risk of
Acknowledgments
The authors wish to thank Professor Veikko Louhevaara and docent Pertti Era for their valuable comments during the preparation of this manuscript. We also thank Dr. Ritva Luukkonen for her advice regarding the statistical methods. The Fire Protection Fund of Finland and the Finnish Work Environment Fund supported this study financially.
References (40)
- et al.
Foot displacement but not velocity predicts the outcome of a slip induced in young participants while walking
J. Biomech.
(2000) - et al.
Lower extremity corrective reactions to slip events
J. Biomech.
(2001) - et al.
Changes in gait when anticipating slippery floors
Gait Posture
(2002) - et al.
Slipperiness of the shoe–floor interface comparison of objective and participative assessments
Appl. Ergon.
(1993) - et al.
Detection of near accidents by measurement of horizontal acceleration of the trunk
Int. J. Ind. Ergon.
(1994) - et al.
Slips, trips and falls in different work groups—with reference to age and from a preventive perspective
Appl. Ergon.
(2001) - et al.
A risk model for the prediction of recurrent falls in community-dwelling elderly: a prospective cohort study
J. Clin. Epidemiol.
(2002) - et al.
The dynamics of slipping accidents
J. Occup. Accid
(1981) - et al.
Effect of slip on movement of body center of mass relative to base of support
Clin. Biomech.
(2001) - Committee for Standardization. European Standard EN 469, 1995. Protective Clothing for Firefighters—Requirements and...
Postural balance and its sensory–motor correlates in 75-year-old men and women: a cross-national comparative study
J. Gerontol. A Biol. Sci. Med. Sci.
Measurement of slipperiness: fundamental concepts and definitions
Ergonomics
Human-centered approaches in slipperiness measurement
Ergonomics
Evaluation of three portable floor slipperiness testers
Int. J. Ind. Ergon.
Predicting slips and falls considering required and available friction
Ergonomics
Functional capacity of men born in 1906–10, 1926–30 and 1946–50
Scand. J. Soc. Med. Suppl.
Postural sway measurements: a potential safety monitoring technique for workers wearing personal protective equipment
Appl. Occup. Environ. Hyg.
Effects of musculoskeletal and sensory degradation due to aging on the biomechanics of slips and falls
Cited by (27)
Influence of radiation mode and intensity on the protective performance of firefighting boots
2024, Journal of Loss Prevention in the Process IndustriesMusculoskeletal Model for Assessing Firefighters’ Internal Forces and Occupational Musculoskeletal Disorders During Self-Contained Breathing Apparatus Carriage
2022, Safety and Health at WorkCitation Excerpt :Biomechanical risk factors for causing MSDs include load carriage, awkward posture, forceful exertion, and repetitive movements [5]. Several studies have reported that firefighters’ MSDs are influenced by heavy and bulky personal protective equipment (PPE) [6,7]. The PPE consists of turnout garments, self-contained breathing apparatus (SCBA), fire boots, helmet, and gloves, adding a significant physical burden during firefighting and leading to restricted mobility and musculoskeletal injuries in different body regions.
Impact of SCBA size and firefighting work cycle on firefighter functional balance
2018, Applied ErgonomicsCitation Excerpt :In a separate study using the same FBT, researchers found no difference among firefighters based on differences in muscular strength or endurance (Punakallio et al., 2005). Both of these studies did not find any impact of age on FBT performance (Kong et al., 2012; Punakallio et al., 2005), though other studies have found that older subjects took longer to complete a FBT and committed more errors (Punakallio, 2003). To date, however, few studies have examined the impact of different configurations of personal protective equipment on functional balance.
Fatigue-induced balance alterations in a group of Italian career and retained firefighters
2014, International Journal of Industrial ErgonomicsA review of risk factors of accidental slips, trips, and falls among firefighters
2013, Safety ScienceCitation Excerpt :It seems prudent, however, to utilize all protective garments during initial and continuing training to increase confidence, balance, and dexterity. One study demonstrated that muscular strength and endurance were not associated with the risk of slips and falls among male firefighters (Punakallio et al., 2005). However, there are important limitations in that study including a small sample size and the muscular capacity tests chosen to assess the subjects.