[Purpose] The external and internal abdominal muscles may be related to gait speed; however, this has not yet been elucidated. In this study, we aimed to clarify the relationship between gait speed and trunk muscle thickness in elderly individuals. [Participants and Methods] The participants were 12 elderly individuals (4 males and 8 females, mean age 83.4 years old, SD ± 0.5) that attend a day service center. We measured the 5 m free gait speed, the 5 m fastest gait speed, and the thickness of five trunk muscles (the rectus abdominis [divided into three parts: upper, central, and lower], external oblique, internal oblique, transverse abdominis, and iliopsoas muscles). [Results] There were positive correlations between the free gait speed and the thickness of the lower rectus abdominis, internal oblique, and transverse abdominis muscles. There were also positive correlations between the fastest gait speed and the thickness of the lower rectus abdominis, internal oblique, and transverse abdominis muscles. [Conclusion] Incorporating muscle strength training of the lower rectus abdominis, internal oblique, and transverse abdominis muscles into existing lower limb muscle training protocols is important to effectively maintain the gait speed of elderly individuals.

[Purpose] This descriptive study examined healthcare-seeking behavior and awareness of physical therapy among Japanese residents of different age groups in Thailand. [Participants and Methods] The study included 145 Japanese residents in Thailand. An online questionnaire was used to collect data on the participants’ sociodemographic characteristics, healthcare-seeking behavior, and awareness of physical therapy. Participants were categorized into three groups based on age, such as young adults, middle-aged adults, and older adults. The χ² test and Fisher’s exact test were used in the data analysis. [Results] The results showed that compared with the older groups, the youngest group was more likely to visit pharmacies, physical therapy clinics, osteopathic clinics, and Thai massage shops to receive healthcare services for injuries or diseases. The participants learned about healthcare services in Thailand through word-of-mouth. Additionally, more than 50% of all participants knew about physical therapy. [Conclusion] There are some differences in health-seeking behavior and awareness of physical therapy among the groups. The youngest group visited physical therapy clinics and 50% of all participants knew about physical therapy.

[Purpose] The purposes of this study were to: 1) survey smartphone addiction among university students, 2) survey the prevalence of upper body musculoskeletal symptoms in relation to the respondents’ sitting posture, and 3) determine the association between smartphone addiction and upper body musculoskeletal symptoms, classified by age and gender. [Participants and Methods] Two self-report questionnaires were employed to collect data from 2,645 university students in Chiang Mai, Thailand. [Results] Of 2,027 respondents (860 males and 1,167 females), the participants’ ages ranged from 18 to 26 years with a mean age of 20.5 ± 1.38 years. The prevalence of smartphone addiction and upper body musculoskeletal symptoms among participants were 15.9% and 30%, respectively. Overall, the mean value of pain severity was 3.66 ± 1.67 out of 10 on the visual analog scale. Multivariate logistic regression analysis revealed that smartphone addiction (OR=6.05, 95% CI: 4.68–7.84), was significantly associated with upper-body musculoskeletal symptoms when adjusted by age and gender. [Conclusion] The prevalence of upper body musculoskeletal symptoms was relatively high, especially for female smartphone users and students aged over 20 years. These results suggest that smartphone addiction may be a potential risk factor for upper body musculoskeletal symptoms in university students.

[Purpose] To clarify the effect of asymmetrical buttock pressure on the shear forces exerted on a buttock. [Participants and Methods] Sixteen healthy adult males participated in this study. A cushion 0 or 2 cm high was placed on the left side of the seat for all participants. The 0- and 2-cm height conditions were called “without difference condition” and “difference condition”, respectively. The back support was inclined at increasing angles, starting at the upright position, to a fully reclined position, and back to the upright position. [Results] With the “difference condition”, the force on the left buttock was 147.4% body weight and that on the right buttock was 105.6% body weight. In contrast, with the “without difference condition”, there was no significant difference in the force on the left buttock and right buttock in terms of percent body weight. [Conclusion] Our results suggest that asymmetrical buttock pressure while in the sitting position causes a difference in shear force exerted on the left and right buttocks when using a reclining chair.

[Purpose] Limited studies exist on the impact of sustained work at a visual display terminal (VDT) on the position and motion of the pelvis and lumbar spine. We evaluated the changes in movement of the lumbar column and pelvis during VDT work. [Participants and Methods] We evaluated the sitting posture of 20 healthy adults while they performed VDT work. The effects of the sitting posture on lumbo-pelvic position and motion were captured using a three-dimensional accelerometer. Between-posture effects of VDT work were evaluated using an analysis of variance (ANOVA). A two-way ANOVA was used to assess the root mean square (RMS) values of the 80-min VDT work period for each posture. A one-way ANOVA was used to evaluate pre- and post-work changes in RMS values during the finger floor distance test (FFD). [Results] People in the dynamic sitting balance chair (DSBC)-based posture demonstrated significantly higher pelvic RMS values than those in reclining and upright sitting postures. The DSBC-based posture was also associated with significantly higher pre- and post-work lumbar and pelvic RMS values during the FFD than in the reclining and upright sitting postures. [Conclusion] The dynamic balance chair may be an effective method of establishing a pattern of spinal exercise during prolonged sitting.

[Purpose] We aimed to obtain new findings by investigating the relationship between the presence or absence of falls and the results from the Frailty Screening Index (FSI), which can be easily carried out. [Participants and Methods] A total of 780 community-dwelling older adults (age ≥65 years) were classified based on whether they had fallen in the past year as those who had fallen at least once (fall group), and those who had not (non-fall group). We compared the study groups using sub-items of the FSI to extract more specific fall-related factors. The FSI is a questionnaire that comprises five items with simple ‘yes/no’ responses. [Results] The following three out of five sub-items of the FSI were extracted as fall-related factors: 1) “no” to the question, “Do you do physical exercise, like walking, at least once a week?”; 2) “yes” to the question, “Do you think you walk slower than before?”; and 3) “yes” to the question, “Have you felt tired for no reason (in the past two weeks)?” [Conclusion] The study results suggest the significance of paying attention to participant responses to the sub-items on the FSI, instead of merely determining their frailty risk based on their total score.

[Purpose] Recently, a photo-based smartphone application for angle measurement—“Grid line imaging application Professional”—was developed to evaluate joint disease treatments. The aim of this study was to determine the accuracy and reliability of the application. [Participants and Methods] We measured the knee joint of a mannequin using an application and a universal goniometer. Twelve examiners measured eight knee joints of mannequins at different arbitrary angles using the application and a universal goniometer. Correlations between the application and universal goniometer measurements were examined using scatter plots and correlation coefficients. Systematic errors of the application were visually confirmed using the Bland-Altman method. Intra-class correlation coefficients were used to evaluate the inter-examiner reliability of the application. [Results] The application and universal goniometer measurements showed a good correlation (r=0.99) and no systematic error. The intra-class correlation coefficient for inter-examiner reliability was 0.999. Furthermore, to evaluate intra-examiner reliability, six examiners measured six different knee joints twice using the application on a 2-day interval. The intra-class correlation coefficient for intra-examiner reliability was 0.982. [Conclusion] The accuracy of the application was equivalent to that of a universal goniometer, and both the inter- and intra-examiner reliabilities of the application were almost perfect.

[Purpose] The purpose of this study was to develop a simpler method to estimate the intervertebral disc compressive force in healthy older adults. We also examined the validity of a simpler estimation formula for patients with spinal diseases. [Participants and Methods] Fifty-two older adults participated in the study. The standing posture was measured using a three-dimensional motion capture system. The intervertebral disc compressive force was calculated using a previously reported method. Correlation analysis was used to detect the relationship between the measured parameters and the intervertebral disc compressive force. Multiple regression analysis was performed to obtain an equation for the intervertebral disc compressive force. Correlation analysis was used to determine the regression equation for the patients with spinal diseases. [Results] Multiple regression analysis showed that trunk flexion/extension angle and body mass were significantly associated with intervertebral disc compressive force. A correlation was found between the measured and predicted values in the healthy older adults, whereas both values were inconsistent in patients with spinal diseases. [Conclusion] The results of our study demonstrated that the trunk flexion/extension angle and body mass are indicators of intervertebral disc compressive force and can be used to assess low back mechanical stress in healthy older adults.

[Purpose] This study investigated the parameters that characterize the knee, hip, and pelvic kinematics during a single-leg squat in preoperative anterior cruciate ligament rupture injury. [Participants and Methods] Overall, 15 patients with unilateral anterior cruciate ligament deficiency were enrolled in this study. For each single-leg squat, data from two-dimensional video cameras and three-dimensional motion analysis were collected. Measurement indices included the articular angles of the knee, hip, and trunk. The anterior cruciate ligament-injured leg was compared with the uninjured leg. [Results] The maximum knee valgus and flexion angles during a single-leg squat were smaller in the injured leg than in the uninjured leg. During the single-leg squat, the effect of “compensatory mechanisms” appeared as knee valgus and flexion movements. In particular, the knee valgus angle decreased in the anterior cruciate ligament-injured leg compared to that in the uninjured leg. [Conclusion] This phenomenon suggests that it is possible to utilize recurrence prevention training for anterior cruciate ligament injury.

[Purpose] This study investigated gait parameter changes in hemiplegic stroke patients who walked with a body weight-supported (BWS) walker and evaluated the usefulness of using the BWS walker in a walking exercise. [Participants and Methods] Nineteen hemiplegic stroke patients hospitalized in a convalescent rehabilitation ward were enrolled in the study. Trunk acceleration was used to evaluate walking with and without a BWS walker. Gait speed, cadence, stride length, step time symmetry, stride time variability, and stride time regularity were calculated from the accelerometer waveform. [Results] Hemiplegic stroke patients had a faster gait speed, walked more symmetrically, and had less variation in their gait cycle when using the BWS walker than when not using it. [Conclusion] Using a BWS walker may help hemiplegic stroke patients learn to walk more efficiently in terms of their gait speed.

[Purpose] Determine if female adolescent soccer players with a history of concussion, impaired K-D scores, and pre-season subjective complaints of neck pain, dizziness, and headache were predisposed to additional risk of musculoskeletal or concussive injury during 10-weeks of competitive play. [Participants and Methods] Twenty-three female high school soccer athletes provided concussion history and reported pre-season subjective complaints. K-D testing was performed pre and postseason. During the 10-week season, all injuries, preventing participation in practice or game, were recorded. [Results] Six reported a history of concussion. Of those six, three injuries were reported, including two concussions and a hamstring strain. Baseline K-D scores were worse in athletes that had two or more pre-season subjective factors compared to those that did not have any. Moderate positive correlations were found between a history of concussion and the number of injuries and a history of concussion and K-D post-test scores. [Conclusion] Findings indicate that pre-season subjective factors of neck pain, dizziness and headache, history of concussion, and K-D potentially increased injury risk. Combining pre-season metrics both at baseline and during the course of the season may assist in better injury risk screening in-season or indicate suboptimal function due to cumulative effects.