Factors associated with the implementation of physical activity among National Institute of Technology students during school closure due to COVID-19 / 体力科学

We examined the characteristics of students with high levels of physical activity during school closure due to the coronavirus pandemic and the factors related to performing physical activity. A total of 404 students, enrolled in Hachinohe National College of Technology, participated in the study. After data cleaning and processing, 345 responses were analyzed. Online classes were held between April 20 and June 5, 2020. A questionnaire was used to survey the lifestyle of students during this period. Additionally, a physical activity survey was conducted in the second week of June 2020, when face-to-face classes resumed. Among students who liked exercising, vigorous physical activity (VPA), moderate to vigorous physical activity (MVPA), and total physical activity in both male and female students and moderate physical activity in male students were significantly higher than that of students who disliked exercising. However, among students who were not afraid of coronavirus, only the VPA of females students was significantly higher than that of students who were afraid. The odds ratios (OR) and 95% confidence intervals (CI) were obtained by logistic regression analysis with the high MVPA group (MVPA ≥ 420 min/week) as the dependent variable and participants’ characteristics as independent variables. We found an association between high MVPA and belonging to an exercise club (OR: 1.85, CI: 1.06–3.22, p=0.030), liking exercise (OR: 4.14, CI: 1.83–9.38, p=0.001), frequently going out (OR: 3.24, CI: 1.74–6.03, p<0.001), and number of factors preventing people from going out (OR: 1.96, CI: 1.05–3.63, p=0.033).

The association of muscle mass and muscle strength with mobility limitation and history of falls in older adults -focusing on sarcopenia and dynapenia- / 体力科学

<p>The purpose of this study was to examine the association of muscle mass and muscle strength with mobility limitation and history of falls in community-dwelling older adults. This cross-sectional study included 420 older adults (207 men, 213 women, 73.7 ± 5.2 years). The participants were classified to following four groups according to their appendicular skeletal muscle mass index (AMI) which was evaluated by bioelectric impedance analysis for skeletal muscle mass in the arms and legs and appendicular skeletal muscle strength Z-score (ASZ) which was calculated from hand-grip strength for upper extremity and peak reaction force during sit-to-stand movement for lower extremity: 1) Low AMI and Low ASZ, 2) Low AMI alone, 3) Low ASZ alone, and 4) Normal. Mobility limitation and history of falls were assessed as a self-reported questionnaire. We used a poisson regression analysis with an adjustment for age, body mass index, knee pain, and back pain. The prevalence of mobility limitation was significantly higher at Low AMI and Low ASZ (relative risk, RR = 5.09, 95% confidence interval, CI 2.08–12.46) and Low ASZ alone (RR = 4.79, 95% CI 2.01–11.39) in men and Low AMI and Low ASZ (RR = 1.70, 95% CI 1.01–2.88) in women than Normal. History of falls was significantly associated with Low ASZ alone (RR = 2.00, 95% CI 1.02–3.91) just in men. These results suggest that low muscle strength per weight rather than low muscle mass per height is an important risk factor to increase mobility limitation in both genders and falls in men.</p>

RELATIONSHIP BETWEEN STRIDE TIME VARIABILITY OF WALKING AND FALL EXPERIENCE IN MIDDLE AGED AND ELDERLY WOMAN / 体力科学

This study was carried out in order to compare stride time (gait) variability of walking not only between young and older adults, but also between “fallers” and “non-fallers”. Moreover, this study aimed to clarify the relationship between stride time variability, balance ability, muscular strength and fall experience. The subjects were 12 young women aged 21.2±2.2 years (young group) and 27 older women aged 66.6±4.4 years (older group). The older group included 14 fallers and 13 non-fallers. They wore an accelerometer on their back and walked at a slow, preferred or fast pace. The time of heel contact was detected by acceleration waveform, and stride time was estimated. The stride time variability was computed by the coefficient of variance (CV) of stride time. The subjects underwent balance tests and muscular strength tests. The CV of stride time at the preferred and fast pace were significantly larger in the older group than in the young group, even though there was no difference in any of the gait speeds between the two. The CV of stride time was significantly larger in fallers than in non-fallers at the fast pace. Path analysis showed that fall experience was affected by an increase in the CV of stride time and decreased balance ability, but less affected by decreased muscular strength. Therefore, this study suggested that stride time variability when walking fast is useful as an early assessment of fall risk in middle-aged and elderly people and that fall experience was affected by stride time variability and balance ability.

AGING EFFECTS ON CO-CONTRACTION OF ANKLE MUSCLES DURING VOLUNTARY SWAY TASK / 体力科学

The aim of this study was to compare co-contraction of ankle muscles between older and young adults performing a voluntary sway task, and identify any relationships between co-contraction, balance ability and muscular strength. The task involved displacement of the center of mass backwards and forwards continually during upright stance under three amplitude conditions, large, small and preferred, with sway speeds of slow, medium and fast. The participants comprised 17 older (64.1±2.9 years) and 14 young (21.3±3.3 years) women. Electromyographic recordings were obtained from the tibialis anterior and the medial gastrocnemius muscles during task performance to calculate the co-contraction index (CCI) and evaluate the relative level of co-contraction of antagonist muscle. Additional measurements were obtained from balance tests including body sway tests, functional reach, gait tests, and the EquiTest (Neurocom), and also muscular strength of plantar flexion and dorsiflexion. The CCI was highest under large sway amplitude, but did not differ among sway speeds. The CCI was higher in the older group (23%) than in the young group (15%). Multiple regression analysis revealed that the CCI correlated with body sway in the EquiTest and functional reach, and dorsiflexion strength. Therefore, this study suggested that co-contraction of ankle muscles increased with aging and related to not only static and dynamic balance abilities, but also ankle dorsiflexor strength.

EFFECTS OF BALANCE EXERCISES ON BALANCE ABILITIES OF COMMUNITY-DWELLING OLDER WOMEN; A RANDOMIZED CONTROLLED TRIAL / 体力科学

This study was to investigate the effects of balance exercises on among static, dynamic and reactive balance ability in community-dwelling older women. Participants comprised 26 community-dwelling older women in Japan, randomized for age and gait speed to the exercise group (n=13) or the control group (n=13). The exercise group performed structured balancing exercises on the sponge and the G ball, once weekly for 24 weeks. The control group performed stretching exercises once per month. Static balance ability was assessed by measuring postural sway and standing on one leg; dynamic balance ability was assessed by measuring functional reach, timed up and go, and gait; and reactive balance ability was assessed using the EquiTest. We also measured knee and ankle strength using an isokinetic machine.At baseline, the two groups were well matched in physical characteristics and in all balance ability and strength tests. After 24 weeks, step length of preferred speed walking (p=0.049) only improved, and peak torque of knee flexion (p=0.050) tended to improve in the exercise group. Any correlations were not found between step length of preferred speed walking and knee flexion strength.These results suggest that these structured balance exercises are effective in improving dynamic, but not static or reactive balance ability. Improvements in dynamic balance ability were not dependent on improved muscle strength.