Objectives: Objective measurements using built-in smartphone sensors that can measure physical activity/inactivity in daily working life have the potential to provide a new approach to assessing workers' health effects. The aim of this study was to elucidate the characteristics and reliability of built-in step counting sensors on smartphones for development of an easy-to-use objective measurement tool that can be applied in ergonomics or epidemiological research. Methods: To evaluate the reliability of step counting sensors embedded in seven major smartphone models, the 6-minute walk test was conducted and the following analyses of sensor precision and accuracy were performed: 1) relationship between actual step count and step count detected by sensors, 2) reliability between smartphones of the same model, and 3) false detection rates when sitting during office work, while riding the subway, and driving. Results: On five of the seven models, the inter-class correlations coefficient (ICC (3,1)) showed high reliability with a range of 0.956-0.993. The other two models, however, had ranges of 0.443-0.504 and the relative error ratios of the sensor-detected step count to the actual step count were ±48.7%-49.4%. The level of agreement between the same models was ICC (3,1): 0.992-0.998. The false detection rates differed between the sitting conditions. Conclusions: These results suggest the need for appropriate regulation of step counts measured by sensors, through means such as correction or calibration with a predictive model formula, in order to obtain the highly reliable measurement results that are sought in scientific investigation.

Objective To examine whether the self‐monitoring interventions of a mobile health app reduce sedentary behavior in the short and long terms. Method We designed a double‐blind randomized control trial. Participants were selected from among the staff of a medical institution and registrants of an online research firm. Forty‐nine participants were randomly assigned to either a control group (n = 25) or an intervention group (n = 24). The control group was given only the latest information about sedentary behavior, and the intervention was provided real‐time feedback for self‐monitoring in addition to the information. These interventions provided for 5 weeks (to measure the short‐term effect) and 13 weeks (to measure the long‐term effect) via the smartphone app. Measurements were as follows: subjective total sedentary time (SST), objective total sedentary time (OST), mean sedentary bout duration (MSB), and the number of sedentary breaks (SB). Only SST was measured by self‐report based on the standardized International Physical Activity Questionnaire and others were measured with the smartphone. Results No significant results were observed in the short term. In the long term, while no significant results were also observed in objective sedentary behavior (OST, MSB, SB), the significant differences were observed in subjective sedentary behavior (SST, β int − β ctrl between baseline and 9/13 weeks; 1.73 and 1.50 h/d, respectively). Conclusions Real‐time feedback for self‐monitoring with smartphone did not significantly affect objective sedentary behavior. However, providing only information about sedentary behavior to users with smartphones may make misperception on the amount of their subjective sedentary behavior.

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Objectives: Increasing attention has been paid to pelvic incidence (PI) as a potential parameter related to low back pain. However, little knowledge exists regarding potential anthropometric landmarks specialized for the estimation of PI. This study aimed to examine the inter-and intra-examiner reliability of potential anthropometric landmarks applicable to estimate PI. Methods: Twenty healthcare workers were recruited as participants. Three were experienced physiotherapists for more than 5 years in clinical practice. Eight anatomical landmarks were selected: (1) the acromion, (2) the upper edge of the iliac crest, (3) the posterior superior iliac spine (PSIS), ( 4) the anterior superior iliac spine (ASIS), ( 5) the upper edge of the greater trochanter, (6) the coccyx, (7) the lateral joint space of the knee, and (8) the lateral malleolus. Photographs of the right-side view of the subjects were used to determine the twodimensional (x, y) coordinates of the landmarks. Results: Most landmark measurements reached acceptable levels for intra-examiner (ICC 1 , 0.64 to 0.98) and inter-examiner reliability (ICC 3 , 0.71 to 0.97). However, as possible anatomical landmarks, the PSIS (ICC 1 0.65, ICC 3 0.48), acromion (ICC 3 0.66), and coccyx (ICC 1 0.64) tended to have relatively low ICCs. Conclusions: Our study suggests that potential anthropometric landmarks on the body surface examined on palpation have acceptable intra-and inter-examiner reliability; however, identifying the acromion, PSIS, and coccyx as anatomical landmarks using the measurement method in this study remain difficult to be considered reliable.

山田翔太 2,3 ，榎原 毅 2 ，上原 徹 3 ，稲田 充 3 ，上島通浩 2 Pelvic incidence (PI) , which is measured by lateral spine radiography, has been attracting attention Pelvic incidence (PI) , which is measured by lateral spine radiography, has been attracting attention as one of the determinants of low back pain. This study assessed the external validity of the Kendall as one of the determinants of low back pain. This study assessed the external validity of the Kendall postural types and the Camper plane categories using their estimated PIs with a validated non-invasive postural types and the Camper plane categories using their estimated PIs with a validated non-invasive way. In addition, we devised four simple classification tools for non-medical personnel to evaluate the way. In addition, we devised four simple classification tools for non-medical personnel to evaluate the Kendall classification (S, M, L, and LL) and the Camper plane categories (S, M, and L) from standing Kendall classification (S, M, L, and LL) and the Camper plane categories (S, M, and L) from standing posture, and evaluated their inter-rater reliability. The results obtained from 62 photographs of lateral posture, and evaluated their inter-rater reliability. The results obtained from 62 photographs of lateral standing posture indicated that there was a significant trend of a dose-response relationship between standing posture indicated that there was a significant trend of a dose-response relationship between the Kendall postural types and the estimated PIs ( the Kendall postural types and the estimated PIs ( p p＝0.06) , but there was no significant difference ＝0.06) , but there was no significant difference in multiple comparisons among them. The maximum inter-rater reliability (Kappa coefficient) of the in multiple comparisons among them. The maximum inter-rater reliability (Kappa coefficient) of the four simple classification tools was 0.41 (95％ CI: 0.37-0.45) . From these results, we concluded that four simple classification tools was 0.41 (95％ CI: 0.37-0.45) . From these results, we concluded that posture assessment using the Kendall postural types and the Camper plane categories cannot be used posture assessment using the Kendall postural types and the Camper plane categories cannot be used for estimating PI. Further improvement is warranted to enhance the inter-rater reliability of the four for estimating PI. Further improvement is warranted to enhance the inter-rater reliability of the four simple classification tools for practical use. simple classification tools for practical use.