The physical performance of children in Japan deteriorated dramatically in fiscal 2019 from the previous year, a survey by the Sports Agency showed Monday.

The overall performance score for boys in the fifth year of elementary school was the lowest since the survey started in fiscal 2008, and that for boys in the second year of junior high school was the worst in the past five years.

The physical performance scores had been on an upward trend for girls and had gradually improved for boys since the survey was launched.

According to the agency, the latest results reflected a drop in time spent on exercise, excluding physical education at schools, growth in time spent using smartphones and rising obesity rates.

Agency officials said they will promote steps to allow students to make exercise a habit, and to have more time for physical activities.

The fiscal 2019 survey was conducted between April and July, covering some 2.01 million students — or almost all children in the two grades across the country.

Their physical performance was evaluated across eight categories, including grip strength and 50-meter sprint time.

With a maximum of 80 points, the total physical performance scores for boys and girls in the fifth grade at elementary schools stood at 53.61 and 55.59, respectively, and those for boys and girls in the second grade at junior high schools were 41.56 and 50.03, respectively.

Those figures were lower by between 0.31 and 0.62 point than the previous fiscal year.

The survey found that male junior high school second graders took 6.31 seconds longer on average to run 1,500 meters. Female junior high school second graders took 3.02 seconds longer to run 1,000 meters.

The average time for a 50-meter run for both boys and girls in the two grades rose by between 0.03 and 0.05 second.

Boys’ grip strength was the weakest ever. Boys in the two grades and female fifth graders at elementary schools logged the poorest performance in ball throwing.

The survey saw a drop in the proportion of both elementary and junior high school students who spend 420 minutes or more on exercise per week, excluding physical education at schools. The size of the declines was bigger for boys than girls.

Students who use smartphones for three hours or more per day logged physical performance scores lower than average.

Agency officials said they were concerned about a possible further deterioration in children’s physical strength due mainly to the growing use of smartphones.

According to the agency, the share of elementary school fifth graders who use smartphones, game consoles or personal computers for one hour or more per day on weekdays stood at 83.3 percent for boys and 73.1 percent for girls.

The share of such male and female second graders at junior high schools came in at 90.3 percent and 87.6 percent, respectively.

The agency said that the share was higher in all grades than in fiscal 2016.