Schoolchildren are becoming physically weaker, according to researchers who have studied how the muscle strength of 10-year-olds has changed over recent years. The team says 10-year-olds have become heavier and taller since 1998, meaning that on average their body mass index (BMI) has remained fairly stable. However their strength and endurance have declined.

“In order to develop strength you have got to use your muscles – you have got to use them repeatedly and you have got to use them regularly,” said Gavin Sandercock, co-author of the research from the University of Essex. “[Children] are not doing the type of activity which will promote strength.”

Writing in the Journal of Science and Medicine in Sport the researchers describe how they took various measurements from more than 300 boys and girls, aged 10, in Chelmsford, Essex, in 2014. These measurements were taken during school PE lessons and included height, weight, distance achieved in a standing broad jump, number of sit-ups in 30 seconds, strength of handgrip and how long the children could keep their chin above gymnasium bars when hanging by their arms. The children were also questioned on how much physical activity they engaged in each week.

The results were then compared to data previously collected for similar sized groups of 10-year-olds in the area in 1998 and 2008. They showed that both boys and girls had become heavier and taller over the years, but also displayed a drop in muscular fitness. The decline also appeared to be speeding up, at least in relation to some aspects..

Between 1998 and 2008 measurements for handgrip and sit-ups fell by an average of 0.6% and 2.6% a year respectively, while between 2008 and 2014 the figures fell on average by 1.6% and 3.9% respectively each year. Overall, Sandercock said there had been a 20% decrease in muscle strength and a 30% decrease in muscle endurance in 10-year-olds over the 16-year period.