We have developed a slip sensor which is knitted by tension-sensitive electro-conductive yarns. When elongating this yarn, its resistance will drop remarkably. Because the yarn is mainly sensitive to deformation along its main axis, a special way to knit these yarns has been proposed to form a slip sensor. This sensor is used in detection of the human fingertip's slip during rubbing action on its surface. We found that, a simple derivative of the sensor's output was sufficient to detect slippage. However, in some cases, the sensor gets troublesome to distinguish between change of normal load and the occurrence of slip, since human implements their action without caring much about keeping the stable applied force on the sensor. Therefore, a well-known DWT (Discrete Wavelet Transform) method is employed to overcome this problem. As a result, depending on the purpose of the application, several data processing methods are employed to detect slippage of human's rubbing action, or robotic fingertip. Results in this paper promise an applicable sensory mean, which can be employed in haptic devices, teleoperation, or robotic skin.
This study was performed to establish a simple method to evaluate knee joint proprioception by examining knee-bending angle, in which Lombard's Paradox phenomenon could be confirmed, in 8 extremities of 7 patients with ACL injured who were diagnosed with ACL rupture at a medical facility (ACL injured group) and 10 extremities of 10 healthy adults (control group). As a result, knee joint proprioception in the ACL injured group was significantly lower than that in the control group (P<0.05). Significantly more incidence of Lombard's Paradox phenomenon was confirmed at the knee-extension position in the ACL injured group (P<0.01), compared with the control group. Significant negative correlation was confirmed between the reproductive angle inaccuracy of joint position sensation, a marker of knee joint proprioception, and Lombard's Paradox phenomenon under the conditions of r=-0.58 and the risk rate of 5%. Based on the results of this study, it was suggested that the knee-bending angle, in which Lombard's Paradox phenomenon was confirmed, would be affected by knee joint proprioception through feedback from the ACL mechanoreceptors, and the angle might be used as a simple evaluation method for knee joint proprioception.
The objective of this study was to clarify the effectiveness of exercise on functional fitness for 2 different styles of Nordic walking (NW). Twenty-five community-dwelling middle-aged and elderly women (mean age: 61.8 ± 6.5 years) volunteered for the study. The subjects were divided into a diagonal-style NW (DIA) group (n = 13) who walked by pressing the poles against the ground diagonally backwards, and a defensive-style NW (DEF) group (n = 12) who used the poles pointing forward as if using assistive canes. In both groups, the exercise intervention consisted of supervised NW for 60 min/day, twice a week for 9 weeks. Subjects were encouraged to engage in non-supervised NW in their neighborhood in addition to the supervised sessions. They were then required to record the frequency and duration of such exercise in their record books. No significant difference was noted in recorded heart rate, %heart rate reserve (%HRR) and the number of steps (DIA group: 121 ± 8 bpm, 58.2 ± 2.8%HRR, 7,671 ± 408 steps and DEF group: 124 ± 13 bpm, 61.6 ± 9.2%HRR, 7,405 ± 269 steps) between the 2 supervised NW groups. There was also no significant difference in the frequency and duration of nonsupervised NW between the 2 groups. Exercise effectiveness was evaluated using functional fitness tests at preand post-intervention levels. Among various functional fitness tests, there was significant group effect in the chair stand (CS). Moreover, in terms of time, there were significant differences in the arm curl (AC), CS, sit & reach (SR), back scratch (BS), up & go (UG), and TW tests. The interaction was significant in the CS and UG tests. Following the intervention, the improvement in lower limb muscle strength index (CS) was greater in the DEF group than in the DIA group; the dynamic balance and agility indices (UG) were greater in the DIA group. Many of the measured variables showed a similar level of improvement while performing short-term NW. However, a significant difference in improvement was noted in some variables, and this is an issue that will require further study.
The purpose of this study was to examine maturity-related differences in anthropometry and body composition in Japanese youth within a single year.Two hundred and ten Japanese youth aged from 13 to 13.99 years participated in this study. Their maturity status was assessed using a self-assessment of stage of pubic hair development. Bioelectrical impedance analysis was used to estimate percent body fat and lean body mass (LBM). Muscle thickness of the anterior thigh, posterior lower leg and rectus abdominis muscles were measured by ultrasound.For boys, height, body weight, and LBM in less mature groups were lower than that in more mature groups. The maturity-related differences were still significant after adjusting for chronological age. On the other hand, muscle thickness values in the lower extremity and abdomen differed among the groups at different stages of pubic hair development, whereas there was no maturity-related difference in the relative values corrected by LBM, except for those thickness values measured at the abdomen. For girls, only the muscle thickness at the anterior thigh and muscle thickness relative to LBM1/3 at the posterior lower leg was significantly affected by maturity status, but significant maturity-related difference was not found after adjusting for chronological age.At least for Japanese boys and girls aged 13 years, maturity status affected body size in boys, but not in girls, and the influence of maturation on the muscularity of the lower extremity and trunk muscles is less in both sexes.
PURPOSE: With increasing interest in addressing quality of life of older individuals, tests such as the Functional Independence Measure (FIM) are widely used measures of infirmity and burden of care. However, these scales are largely qualitative and especially problematic when assessing movement-based tasks. While effective, reliable analysis of human movement is technically complicated and expensive; an infrared depth sensor is potentially a low-cost, portable devise which may provide a quantitative aspect to clinical testing. Our purpose was to assess the utility of the KinectTM sensor in providing an objective evaluation of human movement using an oft measured ADL (march-in-place test; MIP). METHODS: Community-dwelling older adults living in 6 districts and were users of daycare 3 facilities within 4 prefectures in JAPAN. Men (n= 31) and women (n= 74) between the age of 62 and 93 years, consisting of independent (IG; n = 58) and dependent (DG; n = 47) older adults performing the March test. FIM was administered to all subjects (scored by a physical therapist). On a separate day, subjects completed a 20-s MIP test and joint point coordinate data was recorded with a KinectTM v2 during the final 10-s of the test. Initial head position is the origin (H (0)) and head position at any time t is H (t). The Euclidean distance | H (t) - H (t) between these two points 0) | was calculated and summed as the maximum moving distance (MMD) max {| H (t) - H (0) |}. RESULTS: Age, height, body mass and BMI were similar between groups. MMD was greater (p<0.05) in DG (0.293 ± 0.187m) than IG (0.153 ± 0.102m), and was related to age (r=0.605, p=0.051). An optimal threshold for MMD identifying frailty was determined by a receiver-operator characteristic curve with a MMD of 0.207m providing the combination of sensitivity (62%) and specificity (79%). CONCLUSIONS: During the 20-s MIP test, the increased MMD observed in DG appears to indicate that staggering during stepping is large. The result seems to represent instability during marching and poor balancing ability in frail adults. The 20-s MIP and associated MMD identifies frailty in the present population with good sensitivity and specificity.
In Japan, Nordic walking (NW) has two style walking method. For one thing, the poles are used to push against the ground towards the back of the body (diagonal style: DIA). The other one, the poles put on forward and using like a cane (defensive style: DEF). This study aims to clarify differences between the two Nordic walking (NW) styles. The subjects were 12 community-dwelling middle-aged and older adults (mean age: 62.4 ± 7.8 years). All of subjects were tested to perform NW in both style for 12 minutes walking around the park. Walking distance, speed, heart rate (HR), energy expenditure (EE) and electromyogram (EMG) amplitude of the upper and lower limbs using surface EMG were assessed. A pole with a built-in load cell measured force used to push the pole into the ground (pole force), pole contact time, and pole impulse. Distances and speed in DIA was significantly higher than DEF. Significant difference in muscle activity was observed between DIA and DEF in the triceps brachii only. EE of DEF was significantly higher than DIA. Poling force and pole impulse in DIA was significantly higher than DEF. These results indicate that when prescribing NW for health promotion, it should be done according to each characteristic in DIA or DEF.
Abstract Background It is unclear whether or not the breakpoint (BP), at which the proportion of each of fat mass (FM) and fat-free soft tissue mass (FFSTM) to body mass (BM) alter, exists in male athletes. We examined the hypothesis that in male athletes, the regional FM and FFSTM-BM relationships have a BP, but the body mass at BP (BM BP ) differs among the arms, trunk, and legs. Methods By using a dual X-ray absorptiometry, whole-body and regional FMs and FFSTMs in the arms, trunk, and legs were estimated in 198 male athletes (20.8 ± 2.1 years; 1.73 ± 0.07 m; 72.7 ± 14.8 kg). To detect the BP in the relationship between each of FM and FFSTM and BM, a piecewise linear regression analysis was used. If a BP was detected in the corresponding relationship, the significant difference between the regression slopes above and below the BP was examined. Results The regression analysis indicated that the BM BP existed in the FM- and FFSTM-BM relationships regardless of region and whole body. For the whole body, BM BP was 81.8 kg for FM and 82.2 kg for FFSTM. In regional FM-BM relationships, BM BP was 80.5 kg for arms, 82.6 kg for trunk, and 63.3 kg for legs, and the regression slopes above the BM BP became higher than those below the BP, and vice versa in regional FFSTM-BM relationships (BM BP 104.6 kg for arms, 80.9 kg for trunk, and 79.0 kg for legs). The relative differences in the slopes between below and above BM BP in the regional FM-BM relationships were higher in the arms and trunk than in the legs, and those in the regional FFSTM-BM relationships in the legs than in the trunk. Conclusion Whole-body and regional FM- and FFSTM-BM relationships for male athletes have breakpoints at which the proportion of the tissue masses to BM alters. The BM BP and differences in the distribution of regional FM and FFSTM around the breakpoint are region specific.
Here, in comparison with community-dwelling middle-aged and older men, we investigated the skeletal muscle mass and bone mineral density of a Japanese alpinist (Mr. A) who, at the age of 80 years, is to date the oldest person to have climbed to the summit of Mount Everest (8,848 m). Using dual X-ray absorptiometry, we determined the appendicular skeletal muscle mass index (SMI), total bone mineral density (tBMD), whole body fat-free mass index (FFMI) and fat mass index (FMI) of Mr. A (84.6 yr) and 209 community-dwelling middle-aged and older men (50-79 yr, mean age: 68.1 yr). The SMI, tBMD, FFMI and FMI were 8.79 kg/m2, 1.075 g/cm2, 22.3 kg/m2 and 9.8 kg/m2, respectively, in Mr. A and 7.46 ± 0.81 kg/m2, 1.020 ± 0.100 g/cm2, 18.1 ± 1.9 kg/m2 and 5.5 ± 1.7 kg/m2, respectively, in the community-dwelling middle-aged and older men. The values in Mr. A were higher than those in the community-dwelling middle-aged and older men, with z-scores for the SMI and tBMD of 1.63 and 0.55, respectively. Mr. A maintained a high skeletal muscle mass and bone mineral density even at the age of 84 years, which may have been attributable in part to his long-term training for mountain climbing.
