The study stopped due to unforeseen circumstances.

The purpose of the study is to investigate the prevalence of pain in the anterior part of the knee, amongst youngsters between 16 and 18 years of age.

Furthermore, this trial intends to study the connection between the pain, hyperpronation of the foot and tight Achilles tendon.

We want to find out if there is a need of an early effort in terms of information, training and/or support for the shoes.

All students (around 300) between 16 and 18 years of age from one Gymnasium, receives a questionnaire. They are asked to answer whether they have had pain in the anterior part of their knee within the last month. If so they are invited to participate in a scientific study. An equivalent group with no pain are invited to participate as a control group.

In both groups navicular drop and drift will be measured together with the dorsal flexion. The investigations are made single-blinded as the investigators do not know if the "patient" has pain or not.

Inclusion Criteria:

• Informed consent, and for those being under 18 years of age, their parents signature.
• Anterior knee pain syndrome and for the control group: no knee pain syndrome

Exclusion Criteria:

• Former knee surgery
• Any form of arthritis
• Diagnosed meniscus or other injuries in the knee