Transient pain and discomfort when wearing high-heeled shoes.

In the dynamic world of fashion, high-heeled footwear is revered as a symbol of style, luxury and sophistication. Yet, beneath the facade of elegance of classy footwear lies the harsh reality of discomfort and pain. Thus, this study aims to investigate the influence of wearing high-heeled shoes on the sensation of pain across different body regions over a period of 6 h. It involved fifty female participants, all habitual wearers of high-heeled shoes, aged between 20 and 30 years. Each participant kept a record of their perceptions of pain and discomfort every hour for a total of 6 h using a 0-10 pain scale with 0 indicating no pain and 10 indicating severe pain. The findings reveal a progressive rise in pain throughout wear, with the most intense pain reported in the back, calcaneus, and metatarsals. The analysis shows that after approximately 3.5 h, participants experience significant increases in pain levels. However, the relationship between heel height and pain is not linear. It appears that a heel height of 7.5 cm is the threshold where overall body pain becomes significant. The study suggests that a duration of 3.5 h of wear and a heel height of 7.5 cm serve as critical points to decrease overall body pain. Moreover, beyond this heel height, knee pain diminishes compared to other body areas possibly due to the shift towards a more neutral posture. The study findings, coupled with the recommendations, can assist footwear designers in crafting not only stylish but also comfortable shoes.

What Aimed Movement Models Fit Distal Pointing With Varying Depth?

OBJECTIVE: With the rapid improvements in drone technology, there is an increasing interest in distal pointing to diffuse drones. This study investigated the effect of depth on distal pointing when the hand does not traverse the entire distance from start to target so that the most suitable mathematical model can be assessed. BACKGROUND: Starting from the Fitts paradigm, researchers have proposed different models to predict movement time when the distance to the target is variable. They do consider distance, but they are based on statistical modeling rather than the underlying control mechanisms. METHODS: Twenty-four participants volunteered for an experiment in a full-factorial Fitts' paradigm task (3 levels of movement amplitude *7 levels of target width *3 levels of distance from participant to screen). Movement time and the number of errors were the dependent variables. RESULTS: Depth has a significant effect when the target width is small, but depth has no effect when the target width is large. The angular version of the two-part model is superior to the one-part Fitts' model at larger distances. Besides, Index of difficulty for distal pointing, IDDP with adjustable k achieves the best fit even though the model is very sensitive to the value of k and the complexity of the model could be resulting in an overfitting. The result implies that the effects of movement amplitude and target width are not comparable and grouping them to form a dependent index of difficulty can be misleading especially when distance is an added variable. CONCLUSION: The angular version of the two-part model is a viable and meaningful description for distal pointing. Even though the IDDP with adjustable k is the best predictor for movement time when depth is an added variable, there is no physical interpretation for it. APPLICATION: A reasonable predictive model for performance assessments and predictions in distal pointing.

Determinants of self-efficacy of driving behavior among young adults in the UAE: Impact of gender, culture, and varying environmental conditions in a simulated environment.

Research on traffic accidents have acknowledged that human error is the leading cause of road accidents around the world. In the UAE, those aged between 18 and 30 years are involved in the most accidents. As a result, this study examines the perception, attitude and driving behavior of young adults in the UAE. Virtual Reality (VR) was used to examine driving behavior because it offers alternatives to assess driving behavior with a high degree of immersive experience in a safe and replicable environment. Participants drove through a virtual environment that resembled the urban environment of Abu Dhabi in the UAE, which included six traffic events. A sample of 12 females and 27 males also completed a pre and post-simulation questionnaire to report and evaluate their personal driving experience in Abu Dhabi. The volunteer group represented young drivers with limited driving experience and diverse cultural backgrounds. Results indicated that male drivers were less adhering to safe driving behavior compared to females. Even though both males and females exceeded the designated speed limit, males traveled longer distances over the limit. Additionally, it was found that young drivers tend to overestimate their skills with factors like gender, cultural background, and driving experience being key contributors. The results indicate that traffic authorities should take into consideration different approaches in the formulation of policies related to young drivers with periodic reassessment of skills and training to enhance the safety of driving in the UAE and the region.

Efficacy of information extraction from bar, line, circular, bubble and radar graphs.

With the emergence of enormous amounts of data, numerous ways to visualize such data have been used. Bar, circular, line, radar and bubble graphs that are ubiquitous were investigated for their effectiveness. Fourteen participants performed four types of evaluations: between categories (cities), within categories (transport modes within a city), all categories, and a direct reading within a category from a graph. The representations were presented in random order and participants were asked to respond to sixteen questions to the best of their ability after visually scanning the related graph. There were two trials on two separate days for each participant. Eye movements were recorded using an eye tracker. Bar and line graphs show superiority over circular and radial graphs in effectiveness, efficiency, and perceived ease of use primarily due to eye saccades. The radar graph had the worst performance. "Vibration-type" fill pattern could be improved by adding colors and symbolic fills. Design guidelines are proposed for the effective representation of data so that the presentation and communication of information are effective.

A one- and two-phased model of aimed movement with eye-hand incompatibility.

Aimed movement is ubiquitous and has been extensively investigated. However, little research exists when the hand movements are incompatible with eye movements such as when viewing through a mirror or when performing laparoscopic surgery. An experiment was designed to investigate how individuals perform under one-dimensional and two-dimensional inversion with direct viewing as a reference condition. Twenty-four right-handed university students participated in this experiment and completed all aimed movements with a full-factorial design of movement amplitude at three levels and index of difficulty at 10-levels in three visual conditions of direct, viewing through a mirror (1D inversion) and observing through a right-angled mirror (2D inversion). Learning is rather rapid with direct viewing and with 1D inversion. However, participants take a longer time to stabilize their performance in the 2D inversion condition. Fitts' law is robust under all visual conditions. The eye-hand incompatibility increases movement time with 2D inversion taking the longest movement time. Movement time (MT) was split into initiation time (IT), distance covering time (DCT) and acquisition time (AT) based on submovements. The distance covering part is the first submovement that is primarily ballistic and covers around 90% or more of total amplitude. Furthermore, AT allows the aimed movement to be split into two phases: ballistic and visual control. The results show that the transition from ballistic to visual control happens at lower Index of difficulty (ID) values as the level of incompatibility increases. Based on the experiment and prior research, it is appropriate to use the model MT = a + b ID + c√A as it can account for the two phases of ballistic and visual control.

Pressure thresholds and stiffness on the plantar surface of the human foot.

A methodology to assess Pressure Discomfort Thresholds (PDT), Pressure Pain Thresholds (PPT) and tissue stiffness on the plantar surface of the foot was developed. Ten male and 10 female participants volunteered for the study. Foot landmarks were used to create a standardised grid-type template of 95 points. For each test point, PPT and PDT values were obtained, and stiffness was calculated for each of the 20 participants. Cluster analyses were performed to determine the regions of similarity for the three dependent variables, PPT, PDT and stiffness. Moran's-I-index was used to determine the spatial auto correlations. The use of k-means clustering showed five distinct clusters while the three dependent variables showed strong correlations to each other. Morisita's similarity index was used to check the similarity of the grid among all participants. Both male and female participants showed a Morisita's index greater than 0.7 confirming the reliability of the foot template. Practitioner Summary: Pressure Discomfort thresholds (PPT), Pressure pain thresholds (PPT) and tissue stiffness were evaluated at 95 points on the plantar surface of the foot. The PPT and related PDT map are useful to design the footbeds of shoes. Based on the data collected, five distinct clusters of locations were identified.

Pointing Device Performance in Steering Tasks.

Use of touch-screen-based interactions is growing rapidly. Hence, knowing the maneuvering efficacy of touch screens relative to other pointing devices is of great importance in the context of graphical user interfaces. Movement time, accuracy, and user preferences of four pointing device settings were evaluated on a computer with 14 participants aged 20.1 ± 3.13 years. It was found that, depending on the difficulty of the task, the optimal settings differ for ballistic and visual control tasks. With a touch screen, resting the arm increased movement time for steering tasks. When both performance and comfort are considered, whether to use a mouse or a touch screen for person-computer interaction depends on the steering difficulty. Hence, a input device should be chosen based on the application, and should be optimized to match the graphical user interface.

A model for combined targeting and tracking tasks in computer applications.

Current models for targeted-tracking are discussed and shown to be inadequate as a means of understanding the combined task of tracking, as in the Drury's paradigm, and having a final target to be aimed at, as in the Fitts' paradigm. It is shown that the task has to be split into components that are, in general, performed sequentially and have a movement time component dependent on the difficulty of the individual component of the task. In some cases, the task time may be controlled by the Fitts' task difficulty, and in others, it may be dominated by the Drury's task difficulty. Based on an experiment carried out that captured movement time in combinations of visually controlled and ballistic movements, a model for movement time in targeted-tracking was developed.

Load distribution to minimise pressure-related pain on foot: a model.

The optimal force distribution to minimise pain or discomfort at the foot-shoe interface is still not known. Most shoe-related products attempt to distribute the load uniformly without much consideration to the bony and soft tissue regions. An experiment was conducted to first determine the pressure pain threshold (PPT) and tissue deformation on the plantar surface of the foot. Circular probes of areas 0.5, 1.0 and 2.0 cm(2) at indentation speeds of 0.5, 1 and 2 mm/s showed that PPT depends on the location stimulated, area of stimulation and the indentation speed. The results also showed that tissue stiffness is quite low for small deformations ( < 4 mm), but significantly higher at large deformations (>4 mm). The stiffness at the larger deformation region was positively correlated with PPT (r = 0.63, p < 0.001). The data were further used to develop a model with PPT, deformation and stimulated area. PRACTITIONER SUMMARY: Pressure at which there is an onset of pain is higher when a larger area of soft tissue is stimulated. Bony areas may be better suited to bear load on smaller areas to minimise pressure-related pain. Thus, manipulating supporting surface stiffness and surface contours can help minimise pain.

A model for the perception of surface pressure on human foot.

The psychophysical relationship between the magnitude of pressure on thirteen test locations of twenty healthy subjects' feet with four probe areas at three indentation speeds and the corresponding perceived sensations were analyzed. The dependency of pressure pain thresholds (PPT) on area, A, and speed, v, can be mathematically modeled in the form, PPT(i) = [a(i) + bLn(v)]A(ß)i = 1,2…13 where ß and b are constants and are dependent on location and gender, and a(i) is a constant highly correlated with foot tissue stiffness. The relationship between the sensory intensity to pressure magnitude appears to follow a modified Stevens' power law with power exponents less than 1.0 and consistent across the 13 test locations with a mean of 0.82 and a range from 0.67 to 0.98. This particular model helps to understand the sensation of pressure threshold and its impact in the design of consumer products.

Open-loop and feedback-controlled mouse cursor movements in linear paths.

Path length (A), path width (W) and movement direction (θ) are identified as the main factors affecting visually-controlled movement times in linear paths. Effects of A and W are well described by Drury's ( 1971 . Movements with lateral constraint. Ergonomics, l4 (2), 293-305.) model in which movement time is linearly related to the ratio of A/W. At low A/W values, departure from linearity has been identified but not investigated in detail. Data are presented for both open-loop and feedback-controlled movements in linear paths at 0, 60 and 150° movement directions. Movement amplitude and path width were varied over a wide range to determine the effects of A and (A/W) on movement time. Movements were found to be made ballistically or in open-loop mode when the ratio (A/W) was less than about 8 to 10 and the movement times were linearly related to √A for all angles of movement. Feedback-controlled movements followed Drury's law; ballistic movements had movement speed linear with √A. PRACTITIONER SUMMARY: Many tasks require manoeuvring equipment or devices through a path of limited width. These movements can be made with or without feedback control, depending on the path constraints. The conditions for the two forms of movement are determined in this research.

Constrained path tracking at varying angles in a mouse tracking task.

OBJECTIVE: This study was aimed to determine the effects of direction and path length on movement time when traversing a constrained path of width, W, in a mouse tracking task. BACKGROUND: Tracking within constrained paths has been demonstrated to hold in many applications. Movement time and velocity of movement have shown very similar relationships, possibly because of the lack of extreme testing conditions. Most previous research evaluated conditions with only constant path length (A) of movement. METHOD: A total of 15 participants performed a mouse steering task within a constrained path at various angles. The independent variables were track width (W), path length, and path angle. Movement time was the dependent variable. RESULTS: Analyses showed a significant effect of movement direction on movement time, and the relationship was approximately sinusoidal and symmetrical about the horizontal axis. Path length had a significant effect on speed of movement, which was not that apparent on movement time. At low A/W values, movements appeared to be ballistic. CONCLUSION: Tracking within constrained paths can be modeled to account for the effect of path angle. APPLICATION: Vertical hand movements, especially within constrained paths, may not be ideal from a performance and biomechanical standpoint. The performance curve gradients are a good way to evaluate and standardize the testing of input devices and to define acceptable speeds for various tolerances in computer and industrial tasks that involve angular motions. The results of this experiment will help designers to optimize products and training programs.

Pressure thresholds of the human foot: measurement reliability and effects of stimulus characteristics.

Information related to reliable values of discomfort thresholds can help to improve the designs of various products. This study aimed to investigate the measurement reliabilities associated with pressure thresholds, while determining the effects of stimulus characteristics (stimulus area, indentation speed) of the human foot. An indentation apparatus was used with four sizes of indentation probes and three indentation speeds. In total, 13 locations on the right foot of 10 male and 10 female participants were tested to determine the pressure discomfort thresholds (PDT) and pressure pain thresholds (PPT). Results show that the tests had very good measurement reliability with intra-class correlations (ICC) greater than 0.8 for the PPT measurements and acceptable reliability (most ICC > 0.75, with a few between 0.5 and 0.75) for the PDT measurements, demonstrating that participants are capable of judging their pain and discomfort thresholds. Pressure sensitivity differs across locations of the foot, with the medial plantar arch of the foot being the most sensitive, followed by the dorsal surface of the foot. The heel area was the least sensitive. PPT and PDT are dependent on the stimulus characteristics of the area and the speed of indentation. A smaller area has a higher PPT and PDT, indicating significant effects of spatial summation. The increase of PDT and PPT at higher speeds may be partially explained by the increase in stiffness because foot tissue exhibits viscoelastic properties. The findings can have a significant impact on the design of footwear and other accessories for improved foot health and comfort. Statement of Relevance: This study investigated the threshold measurement reliability while determining the pressure sensitivity on the surface of the foot with varying stimulus characteristics. The findings may be very useful in the design of footwear and other accessories for improved comfort and reduced injuries.

An indentation apparatus for evaluating discomfort and pain thresholds in conjunction with mechanical properties of foot tissue in vivo.

The mechanical properties of human foot tissue in vivo as well as discomfort and pain thresholds are important for various applications. In this study, an apparatus for measuring the discomfort and pain thresholds and the mechanical properties of human tissues is presented. The apparatus employs a stepper motor that controls the indentation speed, as well as a load cell and potentiometer that determine the corresponding reaction force and tissue deformation (displacement), respectively. A LabVIEW program (LabVIEW 8, National Instruments Corporation; Austin, Texas) was developed to control the indentation via a data acquisition card. The apparatus can accommodate indentor displacements up to 35 mm and can impart forces up to 150 N at a controlled indentation speed in the range of 0 to 10 mm/s. Tests showed that the displacement measurement error is <0.17 mm in the nominal range (0.5% in the full scale) and the measurement error of force is <1.6 N in the nominal range (1.1% in the full scale). Experimental results indicate that the apparatus is reliable and flexible for measuring the mechanical properties of foot tissue in vivo in conjunction with pain and discomfort thresholds.

Foot arch characterization: a review, a new metric, and a comparison.

BACKGROUND: The medial longitudinal arch of the foot is important because it helps protect the foot from injury. Researchers have developed many measures to quantify the characteristics of the arch, and there is ongoing debate about the suitability of these different metrics. This article compares the various measures related to the foot arch, including a new metric, the midfoot dorsal angle, and then investigates the differences in the dimensional measures among various foot types. METHODS: The right feet of 48 healthy individuals (24 men and 24 women) were measured, and various metrics, including the arch height index, the navicular height to arch length ratio, the arch index, the footprint index, the subjective ranking, the modified arch index, the malleolar valgus index, and the midfoot dorsal angle, were determined. RESULTS: Correlation analyses showed that the arch index obtained from the inked footprint has a moderate to high correlation (Pearson correlation coefficients >0.50) with all measured foot-type metrics except for the malleolar valgus index. There were no differences in participant age, stature, weight, body mass index, foot length, foot width, and midfoot height among high, normal, and low foot arches. However, the high-arched group had significantly shorter arch lengths but larger navicular heights and higher midfoot dorsal angles compared with the low-arched group. There were differences in force distributions and peak pressures as well. The rearfoot had more loading and greater peak pressure whereas the midfoot had less load in the high-arched group compared with the low-arched group. CONCLUSIONS: The midfoot dorsal angle may be an appropriate metric for characterizing the foot arch because it is quick and easy to measure, without the tedious procedures associated with area calculations and dimension measurements.

Footbed shapes for enhanced footwear comfort.

A shoe wearer's comfort is related to the shape of the footbed of a shoe. Even though the footbed shape is important in footwear design, there exists no methodology to evaluate the existing guidelines used in last making. Thirty-two females participated in an experiment where heel seat length, heel seat inclination and heel height were investigated using the profile assessment device. The dependent variables were plantar pressure and perceived feeling of each participant. The results show that perceived feel is best for wedge angles of 4 degrees and 5 degrees at a heel height of 25 mm, 10 degrees and 11 degrees at a heel height of 50 mm and 16 degrees and 18 degrees at a heel height of 75 mm. A regression model was derived and this explained approximately 80% of the variation of perceived feeling with the contact area, peak plantar pressure and percentage of force acting on the forefoot region. Both heel wedge angle and heel seat length play an important role in the perceived feel of high-heeled shoes. This study, in relation to the load-bearing heel part of a shoe, highlights the importance of good footbed design. The findings can be used to design footwear with enhanced comfort.

Pistol shooting accuracy as dependent on experience, eyes being opened and available viewing time.

A study of the shooting accuracy of three groups of pistol shooters is reported. The groups included (i) experienced gas pistol shooters; (ii) persons with experience in video shooting games; and (iii) persons with no shooting experience. The viewing time was varied in the tests. The results showed that experience had a significant effect on the mean and root mean square (RMS) shooting errors at the target. The results also showed that the viewing time does not need to exceed about 2s for an experienced pistol shooter and about 3s for a novice shooter to reach the best performance. Two models for the effects of limited viewing time are proposed; both models fit the data well when the viewing time is less than about 2s. The results indicated that the differences occurring with varying levels of experience are due to postural balance and not due to the aiming or cognitive component of the task.

Effects of pen design on drawing and writing performance.

Two experiments are reported with the aim of determining the effect of pen shape and size on two different types of task: drawing and writing. Experiment 1 attempted to determine the optimum shape and size of shank for ball-point pens used to perform an accurate drawing task. Twenty-seven participants used a total of nine different pens. Drawing performance was measured by having the subjects follow mazes of different size. The dependent variables were drawing movement time and drawing accuracy. The results indicate that the pen with an equivalent diameter of 8mm had the best accuracy during drawing, even though it had the lowest speed. The results confirm the applicability and validity of the Drury tracking model for such a task. Even though users tended to prefer larger pens, their accuracy with such pens tended to be low. In a second experiment, subjects performed a writing task (with no accuracy constraints) and rated their preference for types of pen. An attempt was made to determine the preferred dimensions of ball-point pens for writing in Chinese and English. A total of 36 'bare-bodied' pens and 20 Chinese subjects were used to evaluate the effects of shape, size and weight on time to write a sentence. The Writing Ability, Comfort and an Overall Rating were given by the subjects. The results indicate that the Chinese subjects preferred a circular shaped pen for writing in both languages. A factor analysis showed that speed, comfort and writing ability are independent parameters in pen evaluations.

Effects of surface characteristics on the plantar shape of feet and subjects' perceived sensations.

Orthotics and other types of shoe inserts are primarily designed to reduce injury and improve comfort. The interaction between the plantar surface of the foot and the load-bearing surface contributes to foot and surface deformations and hence to perceived comfort, discomfort or pain. The plantar shapes of 16 participants' feet were captured when standing on three support surfaces that had different cushioning properties in the mid-foot region. Foot shape deformations were quantified using 3D laser scans. A questionnaire was used to evaluate the participant's perceptions of perceived shape and perceived feeling. The results showed that the structure in the mid-foot could change shape, independent of the rear-foot and forefoot regions. Participants were capable of identifying the shape changes with distinct preferences towards certain shapes. The cushioning properties of the mid-foot materials also have a direct influence on perceived feelings. This research has strong implications for the design and material selection of orthotics, insoles and footwear.

Modelling foot height and foot shape-related dimensions.

The application of foot anthropometry to design good-fitting footwear has been difficult due to the lack of generalised models. This study seeks to model foot dimensions so that the characteristic shapes of feet, especially in the midfoot region, can be understood. Fifty Hong Kong Chinese adults (26 males and 24 females) participated in this study. Their foot lengths, foot widths, ball girths and foot heights were measured and then evaluated using mathematical models. The results showed that there were no significant allometry (p > 0.05) effects of foot length on ball girth and foot width. Foot height showed no direct relationship with foot length. However, a normalisation with respect to foot length and foot height resulted in a significant relationship for both males and females with R(2) greater than 0.97. Due to the lack of a direct relationship between foot height and foot length, the current practice of grading shoes with a constant increase in height or proportionate scaling in response to foot length is less than ideal. The results when validated with other populations can be a significant way forward in the design of footwear that has an improved fit in the height dimension.