BackgroundThe purpose of the present investigation was to compare the bouts of daily physical activity (PA) determined by three different accelerometer epoch lengths under free-living conditions.MethodsOne hundred thirty-four adults (50 ± 7 years) wore an accelerometer (Lifecorder) for 7 consecutive days under free-living conditions in order to determine the time spent in physical activity of light intensity (LPA), moderate intensity (MPA), vigorous intensity (VPA), moderate to vigorous intensity (MVPA), and the total physical activity (TPA; sum of LPA, MPA and VPA). Additionally, all PA was divided according to the bout durations (sporadic, >3 min, >5 min, and > 10 min). These indices of PA were analyzed using three different epoch lengths (4 sec, 20 sec and 60 sec) derived from the accelerometer.ResultsThe LPA significantly increased in association with increases in the epoch length (48.7 ± 15.9 to 178.7 ± 62.6 min/day, p < 0.05). The amount of sporadic VPA determined by the shortest epoch length (2.9 ± 5.2 min/day) was significantly longer than the two remaining epoch lengths (1.1 ± 2.4 to 0.9 ± 2.5 min/day, p < 0.05). The times of the MVPA bouts lasting longer than 3 minutes determined using the 4-second epoch length (2.6 ± 5.4 to 7.7 ± 10.0 min/day) were significantly shorter than those determined using the other two settings (6.5 ± 10.5 to 13.8 ± 13.8 min/day, p < 0.05). The frequencies of the MVPA bouts lasting longer than 10 minutes determined using the 4-second epoch length (0.2 ± 0.3 bouts/day) were significantly lower than those determined using the other two settings (0.3 ± 0.4 bouts/day, p < 0.05).ConclusionThe epoch length setting of the accelerometer affects the estimation of the PA bouts under free-living conditions in middle-aged to older adults.

The 12-week SJ program was easily performed by older adults with low skeletal muscle mass, improved aerobic capacity, muscle function, and muscle composition in older adults.

The purpose of the present investigation was to assess the relationship between bouts of very short daily physical activity (PA) lasting <10 min with obesity and abnormal fat distributions. A total of 42 females (age 50±6 years, height 156±5 cm, body weight 54±8 kg, body mass index 22±3 kg/m2) participated in the present investigation. Computed tomography was used to evaluate the area of visceral adipose tissue and subcutaneous adipose tissue (VAT and SAT). All participants wore a pedometer with a one-axial accelerometer (Lifecorder, Kenz, Japan) in order to determine their frequency (bouts/day) of PA and moderate to vigorous intensity PA (MVPA). The total frequency of PA and MVPA, including all bout durations, was not significantly associated with the body fat distribution. The frequency of PA lasting longer than 3 min and 5 min, and MVPA lasting longer than 1 min and 3 min were significantly associated with the area of the VAT (p<0.05). A smaller area of VAT was associated with a higher frequency of PA and MVPA lasting 1-5 min. The present investigation did not find that very short bouts of PA lasting<1 min played a significant role in controlling abdominal fat distribution.

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To assess the association between very short daily non-exercise physical activity (PA) lasting <5 min and metabolic syndrome (MS). A total of 42 females (50 ± 6 years) wore a pedometer with a one-axial accelerometer (Lifecorder, Kenz, Japan) to determine the time and the frequency of PA and the moderate to vigorous intensity PA (MVPA). In addition to the PA and the MVPA (PA(all) and MVPA(all)), the PA and MVPA were analyzed based on the bout duration, such as >32 s, >1 min, >3 min, and >5 min (PA(32S), PA(1M), PA(3M), PA(5M); MVPA(32S), MVPA(1M), MVPA(3M), MVPA(5M)). MS was defined according to the Japanese standard based on waist circumfluence, blood lipids, blood glucose, and blood pressure. The frequency of the MVPA(1M) was significantly lower in subjects with MS compared with that in subjects without MS (P < 0.05). The frequency of MVPA(32S) and MVPA(1M) was significantly associated with the HDL cholesterol (P < 0.05). The frequency of PA(3M) and PA(5M) was significantly associated with the fasting glucose level (P < 0.05). In contrast, we could not find any significant relationships between MS and the components of MS and the frequency of PA lasting <32 s. These results demonstrated that very short non-exercise PA, such as MVPA lasting >32 s to 3 min, has significantly associated with the components of MS. The specific advantages with regard to PA lasting <32 s remain unclear.