Stretching exercises for growing children: evaluation of obesity, flexibility, pain and injury of musculoskeletal organs before and one year later.

Rapid bone development in growing children causes excessive tension in the lower extremities' muscles and tendons, leading to reduced flexibility and increased musculoskeletal disorder risk. Further, lack of exercise causes obesity. Therefore, we created a stretching exercise protocol to prevent musculoskeletal disorders in elementary school (middle and upper grades) children during their growth period, when rapid bone development begins. We examined the effects on pain, injury, and flexibility. Fifty-three (boys: 34, girls: 19) students in grades 3-5 (ages 9-11) performed the stretching exercises at school thrice a week for one year, and we compared the results before and a year after the intervention. A three-minute stretching exercise routine achieved an intensity of 4.6-4.9 metabolic equivalents (METs; equivalent to brisk walking). Obesity (=1.000), flexibility problems (inability to bend forward [=0.754] or squat problems [=1.000]), bone/joint pain (=1.000), and injury (=1.000) did not significantly increase. Stretching exercises during the growth period may help prevent childhood musculoskeletal disorders, obesity, and flexibility loss.