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Footwear outsole design is an important factor for shoe-floor friction and for preventing slipping. Shoes with small, uniformly-separated tread blocks (often included on slip-resistant shoes) have ...

Ladder falls from overreaching are a problem in older adults. Evidence suggests ladder use behavior to be dependent on interfacing user and environmental circumstances (i.e. situational factors). This study investigates the effects of situational factors (remaining debris, ladder position, time into task, hand dominant reach, reaching disposition) on reaching during a gutter clearing task on a ladder in 104 older adults. Reaching was quantified as the maximum lateral center of pressure (COP) displacement from the ladder's center. A reach was classified as an overreach when the COP displaced outside the ladder width, indicative of a ladder tip. Reaching disposition, remaining debris, ladder position, and the interaction of reaching disposition and remaining debris predicted 20% of the reaching variability during the ladder task. Overreaching was observed in 40% of participants accounting for 13% of all extended reaches (beyond ladder). This work can guide interventions on mitigating overreaching and improving ladder safety.

Ladder fall and injury risk increases with age. People who present to a hospital after an injurious ladder fall have been surveyed, but little is known about ladder use in the community. The purpose of this study was to: (1) document salient factors related to ladder safety, and (2) determine physical, executive function, psychological and frequency-of-use factors associated with unsafe ladder use in older people. One hundred and two older people (aged 65+ years) were recruited. Participants completed questionnaires on demographics, health, and ladder use (type, frequency, task, behaviours) and underwent assessments of physical and executive function ability. Results showed both older men and women commonly use step ladders (61% monthly, 96% yearly), mostly inside the home for tasks such as changing a lightbulb (70%) and decorating (43%). Older men also commonly use straight ladders (27% monthly, 75% yearly), mostly outside the home for tasks such as clearing gutters (74%) and pruning trees (40%). Unsafe ladder use was more common in males and individuals with greater ladder use frequency, greater quadriceps strength, better upper limb dexterity, better balance, better stepping ability, greater self-reported everyday risk-taking, a lower fear of falling, and fewer health problems compared to their counterparts (all p &lt, 0.05). These findings document ladder use by older people and provide insight into unsafe ladder behaviours that may be amenable to interventions to reduce ladder falls and associated injuries.

Introduction: Slips, trips, and falls are a major cause of injury in the workplace. Footwear is an important factor in preventing slips. Furthermore, traction performance (friction and under-shoe fluid drainage) are believed to change throughout the life of footwear. However, a paucity of data is available for how traction performance changes for naturally worn, slip-resistant footwear. Method: The presented research is a preliminary analysis from an ongoing, larger study. Participants wore slip-resistant footwear while their distance walked was monitored. Friction and under-shoe fluid pressures were measured using a robotic slip tester under a diluted glycerol contaminant condition after each month of wear for the left and right shoes. The size of the worn region was also measured. Results: Friction initially increased and then steadily decreased as the distance walked and the size of the worn region increased. Fluid pressures increased as the shoes were worn and were associated with increased walking distance and size of the worn region. Discussion: Consistent with previous research, increases in the size of the worn region are associated with increased under-shoe fluid pressures and decreased traction. These trends are presumably due to reduced fluid drainage between the shoe-floor interface when the shoe becomes worn. Conclusions: Traction performance changes with natural wear. The distance walked in the shoe and the size of the worn region may be valuable indicators for assessing loss of traction performance. Practical Applications: Current shoe replacement recommendations for slip-resistant shoes are based upon age and tread depth. This study suggests that tools measuring the size of the worn region and/or distance traveled in the shoes are appropriate alternatives for tracking traction performance loss due to shoe wear.

Older adults have the highest incidence of domestic ladder falls, but little investigation has been given to this important injury issue. There is therefore a need to understand the influence of individual factors like physical and cognitive ability and psychological status on safe and effective ladder use in this population. This study investigated associations between vision, lower and upper limb sensation, upper limb control, strength, balance, cognitive function and psychological status with task completion time and number of ladder moves taken in a simulated roof gutter clearing task on a straight ladder in 97 older adults. Several measures from upper limb control, strength, balance, processing speed, executive function and psychological domains were significantly associated with the two ladder task performance measures. Upper limb bimanual coordination, knee extension strength, coordinated leaning balance, and self-reported risk-taking were identified as independent and significant predictors of task completion time in a multiple regression model, predicting 56% of the variability in ladder task completion time. Upper limb bimanual coordination and proprioception, simple reaction time and coordinated leaning balance were independent and significant predictors of the number of ladder moves in a separate multiple regression model, predicting 38% of the variability in ladder moves taken. These findings help identify individuals at greater ladder fall risk and can guide ladder fall interventions, such as strength and balance training, ladder design and targeted safety instructions.

The hands are believed to be important for arresting falls from ladders. Yet, there is a paucity of kinetic data for the hand-handhold interface during recovery from a ladder climbing perturbation. This study quantified the hand-rung forces utilized after ladder climbing perturbations and the factors (upper body strength, fall severity, reestablished foot placement) contributing to hand-rung force. A ladder rung was released under the foot of the participants to simulate a climbing misstep perturbation. Hand-rung forces after the perturbation were quantified from load cells connected to two ladder rungs. Mean peak hand-rung force magnitudes were found to range between 46% and 84% of the climber’s body weight. These magnitudes approached and, in some cases, exceeded individuals’ grasping capacity. Individual upper body strength was not found to consistently contribute to hand-rung force, but increased hand-rung force was clearly linked with greater fall severity after an ascending perturbation. Individuals that reestablished foot placement after an ascending perturbation utilized lower hand-rung forces. Therefore, this study suggests hand-rung force to be dependent on circumstances of the falling event (fall severity, reestablished foot placement) as opposed to the climber’s capability of producing upper body force. This knowledge highlights the importance of handhold and ladder designs for arresting a falling event, and is critical to inform ladder fall interventions such as designing handholds that resist high forces and permitting steps that enable reestablished foot placement.

There is a need for pedagogical techniques that increase student engagement among underrepresented groups in engineering. Relating engineering content to student interests, particularly through biomechanics applications, shows promise toward engaging a diverse group of students. This study investigates the effects of student interests on engagement and performance in 10th grade students enrolled in a summer program for students underrepresented in the science, technology, engineering, and mathematics fields. The authors assessed the effects of interest-tailored lectures on student engagement and performance in a 5-week program with bioengineering workshops, focusing on the delivery of biomechanics content. A total of 31 students received interest-tailored lectures (intervention) and 23 students received only generic lectures (control) in biomechanics. In addition, the authors assessed the effects of teaching method (lecture, classroom activities, and laboratory tours) on student engagement. The authors found interest-tailored lectures to significantly increase student engagement in lecture compared with generic lectures. Students that received interest-tailored lectures had an insignificant, but meaningful 5% increase in student performance. Students rated laboratory tours higher in engagement than other teaching methods. This study provides detailed examples that can directly assist student teaching and outreach in biomechanics. Furthermore, the pedagogical techniques in this study can be used to increase engagement of underrepresented students in engineering.

Fundamental to the advancement of scientific knowledge is unbiased, accurate and validated measurement techniques. Recent United Nations and landmark Nature publications highlight the global uptake of mobile technology and the staggering potential for big data to encourage people to be physically active and to influence health policy. However, concerns exist about inconsistencies in smartphone health apps. Big data has many benefits, but noisy data may lead to wrong conclusions. In reaction to the increasing availability of low quality data; we call for a rigorous debate into the validity of substituting big data for accurate data in health research. We evaluated the step counting accuracy of a smartphone app previously used by 717,527 people from 111 countries. Our new data (from 48 participants; aged 21–59 years; body mass index 17.7–33.5 kg/m2) revealed significant (15–66%) undercounting by Apple phones. In contrast to the generally positive performances of wearable devices for stereotypical treadmill like walking, we observed extraordinarily large (0–200% of steps taken) error ranges for both Android and Apple phones. Unconscious bias (developers’ perceptions of usual behaviour) may be embedded into many unvalidated smartphone apps. Consumer-grade wearable devices appear unsuitable to detect steps in people with slow, short or non-stereotypical gait patterns. Specifically, there is a risk of systematically undercounting the steps by obese people, females or people from different ethnic groups resulting in biases when reporting associations between physical inactivity and obesity. More research is required to develop smartphone apps suitable for all people of the heterogeneous global population.

This study developed a method to quantify required coefficient of friction (RCOF) during ladder climbing. This method was then used to assess the impact of ladder angle on slip risk. Just like in gait, we assert that slip risk during ladder climbing could be determined using RCOF. Subjects climbed a ladder positioned at three angles (90°, 82.75°, and 75.5°). Forces were measured using a force plate and then projected onto the orientation of the shoe-rung contact region to determine shear and normal forces. The maximum RCOF was determined from the force plate forces and shoe orientation with a set of criteria. The maximum RCOF for a ladder set at 90° and 82.75° was significantly larger than from the maximum RCOF for a ladder set at 75.5°. The maximum RCOF increased as the ladder became steeper, indicating climbers may be more susceptible to slipping while climbing a steeper ladder.

A fall from a ladder is the most common cause of a fatal fall injury to a lower level. Current guidelines recommend proper ladder climbing to avoid a ladder fall, but there is a lack of understanding on safe ladder climbing biomechanics. The purpose of this study was to investigate the effects of different temporal (2-beat, 4-beat) and coordination (lateral, diagonal) ladder climbing patterns on fall severity. In this study, fall severity is quantified as the peak weight supported by a safety harness (normalized to body weight) after a climbing perturbation. A greater harness force is associated with a greater probability of a falling event resulting into a fall. The airborne times of the hand and foot for each climbing pattern were investigated to better understanding differences between climbing patterns. This study did not find climbing patterns to affect fall severity. Thus, the events that occur after a ladder climbing perturbation may be more critical to consider when investigating ladder fall severity. Hand and foot airborne times varied by climbing pattern. Specifically, hand airborne times for the lateral coordination pattern were 19% longer than those of the diagonal coordination pattern. Foot airborne times of the 2-beat temporal pattern were 15% longer than those of the 4-beat temporal pattern. Increased airborne times may be indicative of overlapping regions and resources competition in the primary cortex.

Ladder falls are a common cause of injury in the domestic setting, particularly among older adults. There is a need, therefore, to understand contributing factors of safe and effective ladder use in this group. This study investigated associations between individual human factors (vision, lower and upper limb sensation, upper limb control, strength, balance, cognitive function and psychological status) with task performance on a ladder (time to climb a household stepladder and change a light bulb) under single and secondary cognitive task conditions in 104 older adults. Measures of upper limb control, strength, balance, cognitive processing speed and psychological domains were significantly associated with ladder task completion time in the single task condition; with the addition of executive function and global cognition significantly associated with ladder task completion time in the dual task condition. Knee extension strength, upper limb bimanual coordination, cognitive processing speed and fear of falling were found to be robust predictors of ladder task completion times. These findings help identify individuals with greater ladder use ability and presumably lower fall risk. This work can guide ladder fall interventions, such as strength and balance training, ladder design and targeted safety instructions.

OBJECTIVE To systematically examine stepping performance as a risk factor for falls. More specifically, we examined (i) if step tests can distinguish fallers from non-fallers and (ii) the type of step test (e.g. volitional vs reactive stepping) that is required to distinguish fallers from non-fallers. DATA SOURCE PubMed, EMBASE, CINAHL, Cochrane Database of Systematic Reviews and reference lists of included articles. STUDY SELECTION Cross-sectional and cohort studies that assessed the association between at least one step test and falls in older people (age ≥ 60 and/or mean age of 65). RESULTS A meta-analysis of 61 studies (n = 9536) showed stepping performance was significantly worse in fallers compared to non-fallers (Cohen'sd 0.56, 95 % CI 0.48 to 0.64, p < 0.001, I2 66 %). This was the case for both volitional and reactive step tests. Twenty-three studies (n = 3615) were included in a diagnostic meta-analysis that showed that step tests have moderate sensitivity (0.70, 95 % CI 0.62 to 0.77), specificity (0.68, 95 % CI 0.58 to 0.77) and area under the receiver operating characteristics curve (AUC) (0.75, 95 % CI 0.59 to 0.86) in discriminating fallers from non-fallers. CONCLUSIONS This large systematic review demonstrated that both volitional and reactive stepping impairments are significant fall risk factors among older adults. Step tests can identify fallers from non-fallers with moderate accuracy.

Ladder slip and falls cause negative financial and health impacts due to their severity and frequency. However, frictional requirements of climbing, which presumably influence slip risk, are unknown. The purpose of this study was to quantify frictional requirements during climbing at different ladder angles. The required coefficient of friction (RCOF) was calculated during ladder climbing and assessed for three ladder angles (75.5°, 82.8°, and 90°). Data was collected from 10 participants at each angle. Kinetic data and kinematic data of the climber’s shoe was collected and used to map friction and normal forces to the shoe. These forces were then used to calculate the RCOF. The RCOF and friction force at 90° was higher than at lower angles (75.5° and 82.8°). RCOF was correlated with shoe angle and body angle supporting both the relevance of shoe orientation and body position to slip risk. This study suggests that frictional requirements of ladder climbing are dependent on ladder angle, shoe orientation, and body angle.

Falls from ladders are a frequent and severe injury. To better understand effective strategies to arrest a falling from ladder event, this study assessed 35 participants on their ability to arrest their body from falling after a ladder climbing perturbation. Peak hand-rung forces were compared with fall severity after an ascending climbing perturbation to assess if greater hand-rung force leads to reduced severity in the falling event. Severity of the falling event was measured by the weight supported in the safety harness (i.e. harness force). Higher harness forces were found to be associated with higher hand-rung forces. Hand-rung forces after a climbing perturbation do not reduce the severity in the falling event. Instead, this study suggests that hand-rung forces are caused by the severity in the falling event. This is critical knowledge because the hands are likely to decouple from the ladder if the severity of the falling event is greater than the grasping capability of the climber.

ObjectiveWe examined the impacts of pulling task (breakaway and pull-down tasks at different postures), glove use, and their interaction on achievable downward pull forces from a ladder rung.BackgroundPosture, glove use, and the type of pulling task are known to affect the achievable forces. However, a gap in the literature exists regarding how these factors affect achievable downward pulling forces, which are relevant to recovery from a perturbation during ladder climbing.MethodsForty subjects completed four downward pulling tasks (breakaway force; pull force at maximum height, shoulder height, and a middle height), using three glove conditions with varying coefficient of friction (COF) levels (cotton glove, low COF; bare hand, moderate COF; and latex-coated glove, high COF) with their dominant and nondominant hand. The outcome variable was the maximum force normalized to body weight.ResultsThe highest forces were observed for the highest hand postures (breakaway and maximum height). Increased COF led to higher forces and had a larger effect on breakaway force than the other tasks. The dominant hand was associated with higher forces than the nondominant hand. Male subjects generated greater forces than female subjects, particularly for higher hand positions.ConclusionThis study suggests that a higher hand position on the ladder, while avoiding low-friction gloves, may be effective for improving recovery from ladder perturbations.ApplicationThis study may guide preferred climbing strategies (particularly those that lead to a higher hand position) for improving recovery from a perturbation during ladder climbing.

Ladder falls cause many fatal injuries. The factors that affect whether a ladder perturbation leads to a fall are not well understood. This study quantified the effects of several factors on a person's ability to recover from a ladder perturbation. Thirty-five participants each experienced six unexpected ladder missteps, for three glove conditions (bare hands, high friction, low friction) and two climbing directions (ascent, descent). Fall severity was increased during ladder descent (p

Ladder falls frequently cause severe injuries; yet the factors that influence ladder slips/falls are not well understood. This study aimed to quantify (1) the effects of restricted foot placement, hand positioning, climbing direction and age on slip outcomes, and (2) differences in climbing styles leading to slips versus styles leading to non-slips. Thirty-two occupational ladder users from three age groups (18-24, 25-44 and 45-64 years) were unexpectedly slipped climbing a vertical ladder, while being assigned to different foot placement conditions (unrestricted vs. restricted toe clearance) and different hand positions (rails vs. rungs). Constraining foot placement increased the climber's likelihood of slipping (p 0.01), while younger and older participants slipped more than the middle-aged group (p 0.01). Longer double stance time, dissimilar and more variable foot and body positioning were found in styles leading to a slip. Maintaining sufficient toe clearance and targeting ladder safety training to younger and older workers may reduce ladder falls. Practitioner Summary: Ladder falls frequently cause severe occupational fall injuries. This study aims to identify safer ladder climbing techniques and individuals at risk of falling. The results suggest that ladders with unrestricted toe clearance and ladder climbing training programmes, particularly for younger and older workers, may reduce ladder slipping risk.