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The elastic stress field caused by an ellipsoidal inclusion with uniform dilatational eigenstrains is investigated for a semi-infinite solid. The result is expressed in terms of derivatives of elliptic integrals. Numerical examples are given to show the effect of the free surface with parameters of depth from the surface and shapes of the inclusion.

[Purpose] The purpose of this study was to compare cervical repositioning errors according to smartphone addiction grades of adults in their 20s. [Subjects and Methods] A survey of smartphone addiction was conducted of 200 adults. Based on the survey results, 30 subjects were chosen to participate in this study, and they were divided into three groups of 10; a Normal Group, a Moderate Addiction Group, and a Severe Addiction Group. After attaching a C-ROM, we measured the cervical repositioning errors of flexion, extension, right lateral flexion and left lateral flexion. [Results] Significant differences in the cervical repositioning errors of flexion, extension, and right and left lateral flexion were found among the Normal Group, Moderate Addiction Group, and Severe Addiction Group. In particular, the Severe Addiction Group showed the largest errors. [Conclusion] The result indicates that as smartphone addiction becomes more severe, a person is more likely to show impaired proprioception, as well as impaired ability to recognize the right posture. Thus, musculoskeletal problems due to smartphone addiction should be resolved through social cognition and intervention, and physical therapeutic education and intervention to educate people about correct postures.

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A traditional soccer ball is constructed using 32 pentagonal and hexagonal panels. In recent years, however, the likes of the Teamgeist and Jabulani balls, constructed from 14 and 8 panels, respectively, have entered the field, marking a significant departure from conventionality in terms of shape and design. Moreover, the recently introduced Brazuca ball features a new 6-panel design and has already been adopted by many soccer leagues. However, the shapes of the constituent panels of these balls differ substantially from those of conventional balls. Therefore, this study set out to investigate the flight and aerodynamic characteristics of different orientations of the soccer ball, which is constructed from panels of different shapes. A wind tunnel test showed substantial differences in the aerodynamic forces acting on the ball, depending on its orientation. Substantial differences were also observed in the aerodynamic forces acting on the ball in different directions, corresponding to its orientation and rotation. Moreover, two-dimensional particle image velocimetry (2D-PIV) measurements showed that the boundary separation varies depending on the orientation of the ball. Based on these results, we can conclude that the shape of the panels of a soccer ball substantially affects its flight trajectory.

Soccer balls such as the Adidas Roteiro that have been used in soccer tournaments thus far had 32 pentagonal and hexagonal panels. Recently, the Adidas Teamgeist II and Adidas Jabulani, respectively having 14 and 8 panels, have been used at tournaments; the aerodynamic characteristics of these balls have not yet been verified. Now, the Adidas Tango 12, having 32 panels, has been developed for use at tournaments; therefore, it is necessary to understand its aerodynamic characteristics. Through a wind tunnel test and ball trajectory simulations, this study shows that the aerodynamic resistance of the new 32-panel soccer ball is larger in the high-speed region and lower in the middle-speed region than that of the previous 14- and 8-panel balls. The critical Reynolds number of the Roteiro, Teamgeist II, Jabulani, and Tango 12 was ~2.2 × 105 (drag coefficient, Cd ≈ 0.12), ~2.8 × 105 (Cd ≈ 0.13), ~3.3 × 105 (Cd ≈ 0.13), and ~2.4 × 105 (Cd ≈ 0.15), respectively. The flight trajectory simulation suggested that the Tango 12, one of the newest soccer balls, has less air resistance in the medium-speed region than the Jabulani and can thus easily acquire large initial velocity in this region. It is considered that the critical Reynolds number of a soccer ball, as considered within the scope of this experiment, depends on the extended total distance of the panel bonds rather than the small designs on the panel surfaces.Electronic supplementary materialThe online version of this article (doi:10.1186/2193-1801-2-171) contains supplementary material, which is available to authorized users.

Abstract. [Purpose] This study examined the effects of consecutive training in dual motor tasks on the gait ability of chronic stroke patients. [Subjects and Methods] Conservative physical therapy was conducted for 29 subjects divided into two groups. The dual-motor task group was also taught a basic motor task and additional motor tasks, whereas the single-motor task training group was taught consecutive single motor tasks. Both groups performed their programs five times a week for 30 minutes over a period of four weeks. For performance measurements, timebased gait variables and space-based gait variables were measured using GAITRite.[Results] The dual-motor task group exhibited statistically significant improvement in the temporal variables of cadence, gait velocity, step time, and cycle time, as well as in the spatial gait variables of step length and stride length. The single-motor task group exhibited significant improvements in cadence, gait velocity. Moreover, according to the comparison of training effects between in the two groups, the temporal gait variables of gait velocity and cycle time and the spatial gait variable of stride length revealed a statistically significant difference. [Conclusions] Compared to the single-motor task training, the dual-motor task training of stroke patients was more effective at improving gait ability

[Purpose] The purpose of this study was to determine whether proprioceptive neuromuscular facilitation (PNF) respiration exercise increases the pulmonary function of normal adults. [Subjects and Methods] Twenty-eight normal adults in their 20s were randomly assigned to an experimental group (n=14) or control group (n=14). Over the course of four weeks, the experimental group participated in PNF respiration pattern exercises for 30 minutes three times per week. Subjects were assessed pre-test and post-test by measurement of pulmonary function (tidal volume, inspiratory reserve volume, expiratory reserve volume, inspiratory capacity, and vital capacity). [Results] Our findings show that the experimental group had significant improvements in expiratory reserve volume and vital capacity. In the comparison of the two groups, the experimental group had higher pulmonary function than the control group. [Conclusion] In this study, the experimental group showed greater improvement in pulmonary function than the control group, which indicates that the PNF respiration exercise is effective at increasing the pulmonary function of normal adults.