The specific aims of this study are to:

• describe how many heel raises and side hops TG athletes of various ages can perform and how far they can jump, one leg at a time.
• examine how calf muscle endurance and hop performance are related to the risk of new injuries in the foot, ankle, and lower leg in TG athletes.

The investigators hypothesise that atletes with superior performance in the tests for muscular endurance and hop performance will report fewer injuries during the follow up period.

TeamGym (TG) is the most common gymnastics discipline in Sweden. There is a relatively high injury incidence of 2,2-3,4 injuries per 1000 hours of gymnastic activity. Muscular fatigue has been proposed as a risk factor for sustaining an injury in gymnastics, but this has yet not been examined.

In TG, the lower extremity is more susceptible to injuries than the spine and upper extremity, with injury rates ranging between 60 - 77% for the lower extremity. More specifically, the foot, ankle, and the lower leg account for 40 - 56% of all reported injuries, consisting mostly of ankle injuries.

In clinical and research settings, heel raises and side hops are commonly used to assess muscular endurance in the lower leg. Furthermore, it is common to also include a hop performance test to assess the physical capacity of an athlete following an injury to the foot, ankle, or lower leg. However, there are normative values published of the aforementioned tests, in TG athletes

The overall purpose of this project is to facilitate and improve the caretaking of TG athletes who have sustained various types of injuries in the foot, ankle and lower leg.

Specific aims are to:

• describe how many heel raises and side hops TG athletes of various ages can perform and how far they can jump, one leg at a time.
• examine how calf muscle endurance and hop performance are related to the risk of new injuries in the foot, ankle, and lower leg in TG athletes.

The investigatorshypothesise that atletes with superior performance in the tests for muscular endurance and hop performance will report fewer injuries during the follow up period.

About 200 athletes who regulary participate in TeamGym training (at least once per week) and understand written and spoken Swedish will be included in this study.

Athletes with a recent injury to the foot, ankle, or lower leg or the presence of with other injuries to the lower limb or spine that may be accentuated or affect test results will be excluded.

Data regarding numbers of new injuries (acute and overuse injuries) in the foot, ankle and/or lower leg within six months after baseline testing aswell as severity score of the overuse injuries will be measured bi-weekly with the Oslo Sports Trauma Research Center (OSTRC) questionnaire.

Inclusion Criteria:

• Regular participation in TeamGym training (at least once per week)
• Understanding written and spoken Swedish

Exclusion Criteria:

• Recent (defined as: in the last 4 weeks before baseline testing) injury to the foot, ankle, or lower leg = exclusion from hop tests.
• Presence of other injuries to the lower limb or spine that may be accentuated or affect test results.

TeamGym athletes (members of the Swedish Gymnastics Federation) in Gothenburg, Sweden.

One of the purposes of the project is describing normative data regarding muscular endurance and hop performance in TeamGym athletes and the results will therefore be published. Thus, there will be no need to make IPD available for other researchers.