Nobuaki Moriyama

Effect of Residence in Temporary Housing After the Great East Japan Earthquake on the Physical Activity and Quality of Life of Older Survivors

OBJECTIVE This study aimed to compare the physical activity level and health-related quality of life (HRQOL) between older survivors residing in temporary housing after the Great East Japan Earthquake (GEJE; temporary housing group) and older individuals residing in their own homes (control group) and to clarify whether mobility function and muscle strength were correlated with physical activity among older temporary housing residents. METHODS Subjects were recruited to the temporary housing group (n=64, 19 men and 45 women) or control group (n=64, 33 men and 31 women) according to their residence. Physical activity was assessed by the number of walking steps determined by using a triaxial accelerometer, mobility function by the Timed Up and Go test, muscle strength by the grasping power test, and HRQOL by the Medical Outcome Study 36-Item Short Form Survey v2. RESULTS In the temporary housing group, reduced physical activity and correlation between physical activity and mobility function in men, and muscle strength in both men and women, were observed. There was no significant difference in HRQOL between groups except for bodily pain in women. CONCLUSION Support for older evacuees should focus on maintaining their physical activity level as well as on HRQOL to avoid deterioration of health in these survivors. (Disaster Med Public Health Preparedness. 2017;11:701-710).

CHARACTERISTICS OF ANKLE MUSCLE ACTIVITY DURING TILTING MOVEMENTS ON A WOBBLE BOARD

Background Balance training is a common component of rehabilitation after ankle sprains. A relatively high activity of the peroneus longus (PL) to the activity of the tibialis anterior (TA) (a low TA/PL ratio) is reported as an effective muscle activity pattern during balance training to prevent inversion ankle sprains. To date, no research has investigated ankle muscle activity during tilting movements on a wobble board. Objective To assess the magnitude of muscle activity of the ankle while inversion and eversion movements of the ankle joint are performed on a wobble board. Design Single-session randomized repeated-measures study design. Setting University laboratory. Participants Seventeen young adults (11 females and 6 males) with no history of ankle injury. Interventions Participants performed tilting movements on a wobble board in a medial and lateral direction while balancing on their non-dominant leg. The frequency of the movement was set at 40 bpm. Muscle activity of the TA and the PL during five cycles of inversion-eversion movements were collected and stored for analysis. Main Outcome Measurements Normalized RMS EMG values (percentage of each participants maximum voluntary isometric contraction; %MVIC) of the TA and PL, along with TA/PL ration in the inversion (wobble board tilted in the lateral direction) and eversion (wobble board tilted in the medial direction) phase. Results There was a significant difference in muscle activity of the PL (inversion phase; 41.6±15.3%MVIC, eversion phase; 59.2±21.5% MVIC, p<0.01) and TA/PL ratio (inversion phase; 52.6±22.3%, eversion phase; 34.1±16.3%, p<0.01). There was no significant difference in muscle activity of the TA (p>0.05). Conclusions The results of the present study indicate that tilting movements on a wobble board in the medial direction (eversion of the ankle joint) may be favorable as an exercise modality after inversion ankle sprains as a high PL activity and a low TA/PL ratio was acquired.

[The effect of different working postures while felling a tree with a chain-saw on trunk muscles' activity].

PURPOSE Many forestry workers who use chain-saws suffer from low back pain. Previous studies have reported that low back pain is related to the working postures while felling a tree with a using chain-saws. However, no previous study has investigated trunk muscle activities during work. The purpose of this study was to clarify the relationship between working postures while holding a chain-saw, and trunk muscles activities as measured by surface electromyography (EMG). METHOD Subjects were 10 males who were not forestry workers. Four task postures while holding a chain-saw were tested: standing, 30(o) trunk flexion, 90(o) trunk flexion and half-kneeling. EMG recordings were obtained bilaterally of the lumbar paraspinal (LP) muscles and rectus abdominis (RA) muscles. Raw EMG data were processed by integrating the EMG and normalizing them to %MVC. The paired t-test was used to detect statistical differences in the activities between the right and left LP muscles and RA muscles. One-factor repeated measures ANOVA was used to compare the bilateral LP and RA muscle activities among the 4 different postures. The significance level was set to less than 5%. RESULTS In the half-kneeling posture, the right LP muscle activity was 14.7% higher than the left LP muscle activity (p<0.05); however, there were no significant differences in muscle activities among the other postures. The right LP muscle activity of 30(o) trunk flexion posture was 25.6% higher than that of the standing posture, and 14.2% higher than that of half-kneeling posture (p<0.05). The bilateral LP muscle activities of the 90(o) trunk flexion posture were the highest of the 4 postures, 16.7% higher than the half-kneeling posture (p<0.05) right LP muscle activity. There was a tendency of increase in the left LP muscle activity when trunk flexion angle increased, but no significant differences among the 4 postures were found. The bilateral RA muscle activities were low and did not significantly differ among the 4 postures. CONCLUSIONS This study showed that when the trunk is flexed, the LP muscle activities change asymmetrically, with the right LP muscle activity increasing significantly compared to the standing posture and the half-kneeing posture, but there was no significant difference in the left LP muscle activity. These results suggest that working postures that involve trunk flexion while felling a tree with a holding chain-saw may lead to increased loading of the LP muscles.