Flexibility does not affect the dorsiflexion of foot and the popliteal angle in young adults

The aim of the study was to assess how flexibility affects the dorsiflexion of foot and the popliteal angle test results in junior high school students.

The subjects were 142 students from the 2nd, and 3rd year of Poznań junior high schools (age between 13 and 15). Each subject was examined 6 times: there were 3 raters, a specialist in orthopaedics, a resident doctor and a physical therapy student, and each of them performed 2 measurements. Flexibility was also measured using the Beighton scale (score from 0 to 9).

Since the Beighton scale is ordinal in order to evaluate the relationship between flexibility and the range of motion Spearman's rank correlation coefficient was calculated. The statistical analysis showed no correlation between flexibility measured on the Beighton scale and the range of passive foot dorsiflexion and the popliteal angle.

The degree of flexibility does not affect the dorsiflexion of the foot and the popliteal angle in junior high students. At this age the range of dorsiflexion is determined by the length of the triceps surae muscle while the popliteal angle depends on the length of the muscles on the back of the thigh.