DATSURYOKU Sensor-A Capacitive-Sensor-Based Belt for Predicting Muscle Tension: Preliminary Results.

Excessive muscle tension is implicitly caused by inactivity or tension in daily activities, and it results in increased joint stiffness and vibration, and thus, poor performance, failure, and injury in sports. Therefore, the routine measurement of muscle tension is important. However, a co-contraction observed in excessive muscle tension cannot be easily detected because it does not appear in motion owing to the counteracting muscle tension, and it cannot be measured by conventional motion capture systems.

Intra-day variation in daily outdoor walking speed among community-dwelling older adults.

Background: Walking speed is an important measure associated with health outcomes in older individuals, such as dependency and death. This study aimed to examine whether the walking speed of community-dwelling older adults varies between time periods within a day, as measured outdoors in daily life. We aimed to determine the types of walking speed variations and examine the factors associated with them.

Association between Daily Living Walking Speed and Walking Speed in Laboratory Settings in Healthy Older Adults.

Although there is evidence on the predictors of adverse health outcomes in older individuals, walking speed has typically been measured in laboratory settings (LWS); LWS may be distinct from individuals' actual walking speed in their daily lives (DWS). We examined whether DWS differs from LWS among older adults, and its association with physical frailty. Participants were 90 community-dwelling older adults.

Three-dimensional shape variation and sexual dimorphism of the face, nose, and mouth of Japanese individuals.

Three-dimensional (3D) shape variations of the face and facial parts in Japanese adults were examined to collect basic data to be used for facial comparison in forensics. In total, 1000 3D facial scans (500 males, 500 females) of Japanese individuals were re-meshed into anatomically homologous shape models and analyzed by principal component analysis (PCA) after Procrustes superimposition. Facial parts (the nose and the mouth) were segmented from homologous face models and analyzed by PCA, too.

Inter-Individual Variability in The Joint Negative Work During Running.

The inter-individual variability of running technique is an important factor affecting the negative work of lower extremity joints that leads to muscle damage. Our study examines the relationships between the negative work of the lower extremity joints and the associated mechanical parameters that account for inter-individual variability in the negative work. Twenty-four young male adults were asked to run on a runway at a speed of 3.

Training Shoes do not Decrease the Negative Work of the Lower Extremity Joints.

Different types of running shoes may have different influence on the negative work of each lower extremity joint. Clarifying this influence can reduce the potential risk of muscle injury. The present study examined the difference in the negative work and associated kinetic and kinematic parameters of the lower extremity joints between training shoes and racing flats during the contact phase of running.

Relationship between body height and spatiotemporal parameters during a 100-m sprint in able-bodied and unilateral transtibial sprinters.

Background: Although anthropometric factors could influence sprint performance in able-bodied sprinters, little is known about the relationships between these anthropometric factors and sprint performance in amputee sprinters.

Objectives: To investigate the relationships between body height and spatiotemporal parameters of 100-m sprints in unilateral transtibial amputee and able-bodied sprinters.

Study Design: This is a cross-sectional study.

COMPARING 3D FOOT SHAPE MODELS BETWEEN TAIWANESE AND JAPANESE FEMALES.

This study compares foot shape and foot dimensions between Taiwanese and Japanese females. One hundred Taiwanese and 100 Japanese female 3D foot scanning data were used for comparison. To avoid the allometry effect, data from 23 Taiwanese and 19 Japanese with foot length between 233 to 237 mm were used for shape comparison.

Age-independent and age-dependent sex differences in gait pattern determined by principal component analysis.

Although various studies have reported significant sex differences in pelvic and/or hip-joint motion during normal walking in healthy adults, it is still unclear whether such differences are among the most dominant age-independent sex differences. This study was conducted to analyze the whole waveform of lower-extremity joint kinematics obtained from 191 healthy adults using a principal component analysis (PCA). The PCA was conducted using a 955×1212 input matrix constructed from the participants' time-normalized pelvic and right-lower-limb-joint angles along three axes (five trials of 191 participants×101 data points×4 angles×3 axes).

Ethnicity and spatiotemporal parameters of bilateral and unilateral transtibial amputees in a 100-m sprint.

Similar to able-bodied sprinters, most of the medals for the 100-m sprint in past Paralympic Games and IPC Athletics World Championships were dominated by West African (WA) and Caucasian (CC) amputee sprinters, not Asian (AS) sprinters. Although these results indicate differences in sprint performance due to ethnicity, little is known about the ethnicity and spatiotemporal parameters of the 100-m sprint for amputee sprinters. The purpose of this study was to investigate the differences in the spatiotemporal parameters of WA, CC and AS sprinters with bilateral and unilateral transtibial amputations during a 100-m sprint.

Does amputation side influence sprint performances in athletes using running-specific prostheses?

Background: For athletes using running-specific prostheses (RSPs), current Paralympic guidelines for track events are generally based on level of amputation, not side of amputation. Although 200- and 400-m sprint races are performed in a counterclockwise direction, little is known about the effects of amputation side on race performance in athletes with unilateral lower limb amputation. The study aim was to test whether athletes using RSPs on their left side have slower race times than those using RSPs on their right side.

Ingress and egress motion strategies of elderly and young passengers for the rear seat of minivans with sliding doors.

This study investigates the motion strategies performed by elderly and young passengers while entering and exiting the rear seat of minivans with sliding doors. A minivan mock-up was constructed with four adjustable parameters to represent nine different conditions of vehicle geometry. Ten elderly male participants (66.

Normative Spatiotemporal Parameters During 100-m Sprints in Amputee Sprinters Using Running-Specific Prostheses.

The aim of this study was to develop a normative sample of step frequency and step length during maximal sprinting in amputee sprinters. We analyzed elite-level 100-m races of 255 amputees and 93 able-bodied sprinters, both men and women, from publicly-available Internet broadcasts. For each sprinter's run, the average forward velocity, step frequency, and step length over the 100-m distance were analyzed by using the official record and number of steps in each race.

Leg stiffness of older and younger individuals over a range of hopping frequencies.

The purpose of this study was to compare spring-mass behavior between older and younger individuals at a range of hopping frequencies. A total of 14 elderly and 14 young subjects performed in-place hopping in time with a metronome at frequencies of 2.2, 2.

Three-dimensional analyses of aging-induced alterations in facial shape: a longitudinal study of 171 Japanese males.

We sought to generate data to facilitate forensic facial comparisons. Specifically, we conducted a longitudinal study of alterations in face shape induced by aging. We obtained two three-dimensional facial shape measurements in 171 Japanese males at intervals of approximately 10 years.

Key joint kinematic characteristics of the gait of fallers identified by principal component analysis.

It has been reported that fallers have a higher risk of subsequent falls than non-fallers. Therefore, if the differences between the movements of recent fallers and non-fallers can be identified, such could be regarded as the basis of the high risk of falling of the former. The objective of the present study was the identification of the key joint kinematic characteristics of human gait related to the risk of falling while walking on level ground.

A protocol for evaluating the accuracy of 3D body scanners.

Scan-derived landmarks locations and surface shapes are more and more used, but there is no commonly accepted protocol for evaluating the accuracy of these measurements. Therefore we propose a protocol for evaluating the accuracy of surface shape and the repeatability of scan-derived landmark locations. According to existing Japanese and German domestic standards, we propose to use an artefact (e.

Questionnaire survey of customer satisfaction for product categories towards certification of ergonomic quality in design.

Customer satisfaction was surveyed for 6 product categories (consumer electronics, daily commodities, home equipment, information systems, cars, and health appliances) by questionnaires based on the Analytic Hierarchy Process. Analyzing weight of evaluation factors, the 6 product categories were reorganized into 4 categories, those were related to 4 aspects in daily living that formed by two axes: home living - mobility life and healthy life - active communication. It was found that consumers were attracted by the actual user test by public institutes for all product categories.

A study of frictional property of the human fingertip using three-dimensional finite element analysis.

Since the tactile perception detects skin deformation due to the contact of an object, it is important to understand contact mechanics, especially, frictional behavior of the human fingertip. The coefficient of friction is recently modeled as a function of the applied normal load in which case the traditional Coulomb's law does not provide a description for the skin surface. When a surface is a rubber-like material, the frictional behavior follows the frictional law of the rubber-like material.

Errors in landmarking and the evaluation of the accuracy of traditional and 3D anthropometry.

Body dimensions are based on landmarks of the body, but the magnitude of error in landmark determination is not well known. Therefore, a study was performed in which 40 subjects were marked five times in total by one highly skilled marker and a novice marker. Immediately after marking, a skilled measurer determined 34 body dimensions that were based on the mark locations.

Deformation of foot cross-section shapes during walking.

To clarify the magnitude of shape change during walking, the shapes of four cross-sections (Forefoot, Instep, Navicular, and Heel) of the right foot during standing and walking were measured using a four-dimensional measurement system we developed (14 Hz) with an accuracy of +/-0.5 mm. Images of the sole were measured using a high-speed video camera (120 Hz).

Geometric modeling of living tissue for subject-specific finite element analysis.

We introduce shape morphing approach to generate subject-specific finite element (FE) models. Different from the conventional approaches, our method generate individual (FE) model by applying spatial transformation to a reference model. It does not, therefore, require time-consuming works such as segmentation and mesh generation.

3D finite element analysis of the frictional behavior of the human fingertip.

Although the tactile sensation is one of the most important senses, little quantitative research has been carried out to investigate the sense of the touch of the fingertip. We developed a three-dimensional finite element model of the fingertip and performed a determination of material properties using an optimization technique so that the contact area of finite element analysis corresponded with that of the experiment when a rigid plane was indented. The estimated material properties agreed with published data and the optimization method is considered to be effective.