Drop Jump Landing Knee Valgus Angle; Normative Data in a Physically Active Population

Aims of the study:

To establish normative values for dynamic knee valgus angles during the functional movement patterns of the unilateral single leg landing (SLL) and the bilateral drop jump landing (DJL), which are two commonly used movements to assess knee motion control function on physically active individuals.

To assess if these values differ between limb, gender and task to evaluate these landing patterns with relation to possible injury mechanics that may result from a variance in knee valgus angles.

The analysis of knee valgus angles using 2-D video systems, as they wanted to prove that this method would obtain both valid and reliable data which would prove a very useful tool in the clinical assessment of patients.

Method:

The study involved 100 participants (50 f, 50 m)

A standard as in all of the 3 methods is that subjects ''have no history of ACL injury or other knee pathology, significant lower limb pathology, lower limb fracture or surgery and had been injury free for 3 months prior to the data collection''.

This study however set a skill level of fitness to a minor extent in comparison to the last summarised study below. The requirements of the participants were to engage in only 3 hours of sporting activity per week. However the subjects were not of a particular sporting complex rather a diverse mix of sports which may have affected test results with relation to the varying skill levels of participants.

Procedure:

Similar to the study below the valgus angle of the knee was taken as the angle that subtended between the lines formed between the markers at the Anterior Superior Iliac spine and middle of the tibiofemoral joint and that formed from the markers on the middle of the tibiofemoral joint to the middle of the ankle mortise. However no guidelines were followed as to the correct placement of the angles for FPPA.

Intra tester reliability was carried out differently in this study in comparison to the other 2 as 10 knee valgus photographs were (5 drop jump landing, 5 step landing) were selected randomly for reassessment of angle.

Subjects were allowed practice trials before each test (SLL and DJ) until they felt comfortable; this was typically 3 to 5 trials. After familiarization each participant performed 3 trials of each test. Both legs were tested and analysed for all tests.

Pros:

The two movement patterns of unilateral single leg landing (SLL) and the bilateral drop jump landing (DJL) are the pinnacle of field sports in relation to deceleration of the athlete and their landing mechanics. These movements are central to our target population (Gaa Athletes), hence to evaluate similar movement patterns and pre-screen these individuals will therefore better prepare and reduce the relative risk of injury associated with dynamic knee valgus.

There was a clear development in population norms from this study in relation to a comparison of previous research which was clearly labelled and displayed in table form which showed the comparison of knee valgus angle findings between the current study and previous research.

On average all of the studies both past and present indicated that for a drop jump landing task knee valgus angle should be symmetrical and in the range of 7-13 for females and 3-8 for males to be described as average for the population