Decline in objective physical activity over a 10-year period in a Japanese elementary school

Abstract

BackgroundThe purpose of this study was to examine the change in accelerometer-derived daily physical activity (PA) and activity record-derived daily activities over a 10-year period in urban elementary schoolchildren in Japan.MethodsA total of 233 sixth-grade children (11–12 years old) in a same elementary school in Kyoto participated in the study (n = 125 and 108 in 1999 and 2009, respectively). The participant rate is 91.9 and 98.2 % in 1999 and 2009, respectively. The size and shape of the school district was not changed. The children were instructed to wear an accelerometer for 5 consecutive days of weekday and to keep minute-by-minute 24-h activity records with the assistance of their parents. The school-day scheduling was similar between 1999 and 2009 (29 and 27 sessions of 45-min class per week, respectively).ResultsFrom 1999 to 2009, step counts considerably decreased (20,832 vs. 12,237 steps per day in boys and 16,087 vs. 10,748 steps per day in girls; P < 0.001) with concomitant significant decreases in total energy expenditure (P = 0.011), activity energy expenditure (P < 0.001), and physical activity level (P < 0.001). Time spent playing outdoors and walking to school were also significantly less in 2009 than 1999 (P < 0.001). Accelerometer-measured PA was significantly associated with the amount of time spent playing outdoors and walking to school.ConclusionsThese results indicate that elementary schoolchildren in 2009 spend less time playing outdoors and walking to school, perform less PA, and take fewer steps than children of a decade ago.

Association between daily step counts and physical activity level among Korean elementary schoolchildren

“…Despite the lack of a significant difference in PAL between boys and girls in the present study, boys took significantly around 2,500 more steps/d than girls (12,578 vs. 10,031). The difference was also similar with the results from most studies reporting elementary school boys having higher step counts than elementary school girls in other countries 6 , 11 , 28 , 29 . In the United states, urban elementary school boys took significantly around 4,000 more steps/d than girls (16,421 vs. 12,332) 28 .…”

“…Likewise, in Japan, Itoi et al . 11 reported that urban elementary school boys took significantly around 1,500 more steps/d than girls (12,237 vs. 10,748). On the other hand, in Korea, a similar population of elementary school boys had similar steps as girls (11,165 vs. 10,708) 6 .…”

“…Our association data between steps/d and PAL showed that around 2,500 steps/d are needed to achieve an increased 0.1 PAL for normal-weight elementary school children. Thus, it has been suggested that elementary school children should spend more time playing outdoors and walking to school to increase PAL 11 .…”

“…Itoi et al . 11 recently reported that steps/d in urban elementary school children (11-12 years old) in Japan considerably decreased during a decade (1999 to 2009) (20,832 vs. 12,237 steps per day in boys and 16,087 vs. 10,748 steps per day in girls) with a concomitant decrease in physical activity level (PAL, the ratio of total energy expenditure (TEE): resting metabolic rate (RMR)) assessed by accelerometry. This result suggests that childhood PAL, specifically steps for daily physical activities, might have decreased over the past few decades.…”

Changes in physical activity over the lifespan: impact on body composition and sarcopenic obesity

“…A negative trend in most aspects of physical fitness, as observed in school‐aged children over a 20‐year interval, is a worrying health trend all over the world and will compromise well‐being of future adults . Modern children have lower physical activity than the children of a decade ago as a result of less time being spent playing outdoors or active transport to school . PAL in school‐aged children, as measured with accelerometers, are shown to decrease in many countries .…”