Bennell K.L., Talbot R.C., Wajswelner H, Techovanich W, Kelly D.H and Hall A.J. Intra-rater and inter-rater reliability of a weight-bearing lunge measure of ankle dorsiflexion. Aust J Physiother. 1998;44(3):175-180.
Regaining dorsiflexion after an ankle injury is one of the most difficult and important aspects of rehabilitation. This paper was designed to assess the reliability of a weightbearing dorsiflexion measure with the knee bent. Given the high levels of force and motion required of the ankle during daily activities such as squatting and descending stairs, and the difficulty of replicating this with manually applied forces, the authors discuss the importance of having a reliable weightbearing measure that can accurately capture the maximum available functional ankle motion.
The subjects were 13 healthy physiotherapy students, with an average age of 19 years. The test involves standing facing the wall, and then lunging forward to reach the knee toward the wall, without lifting the heel. Subjects attempted to move their feet as far backwards as possible, while still being able to both touch their knee to the wall and keep their heel flat. Heel contact with the floor was manually maintained by the assessing therapist. The result was recorded two ways: distance of the toes to the wall, and ankle dorsiflexion angle as measured by inclinometer on the tibia. To assess the inter-tester reliability, 4 assessors – 3 experienced physiotherapists and one student – performed sequential evaluations, and 2 of the therapists performed re-tests one week later to assess intra-tester reliability. The test was carried out three times by each assessor, and the average of the results was recorded.
The inter-rater ICCs were .97 for the angle measurement and .99 for the distance measurement, indicating nearly perfect reliability. The intra-rater reliability was also within that range, and the results measured by the student were found to be consistent with the other testers. Given a standard error of 3 approximately 3 percent for both methods, the authors indicate that a change of greater then 1 centimeter or 3° would be required to be confident in a change in motion, at least among subjects without injury.
Despite these excellent outcomes, there are several things to keep in mind. As the subjects in this study were young and free of any ankle pathology, they were likely reaching their true endrange, a fact supported by the wide variation in the measurement between subjects (30-68°). Pain, swelling, balance, or difficulty with weightbearing may influence the ability to reach endrange, influencing the reliability of the findings. There was also no mention of subject or tester blinding that I could find, a finding that could certainly affect the intra-rater reliability, but would likely have little effect on the inter-rater reliability, unless the subjects with repetition were able to learn where to place their feet for the most efficient outcome. It is difficult to accept the results of a reliability study that does not include blinding, and this certainly could have an effect on the standard error measurement. Given these drawbacks, this study shows the test to be reliable in a healthy sample, and it certainly appears to be a more functional and reliable test than dorsiflexion in lying.
I was at a continuing education course once where the instructor had me come up to the front to demonstrate how to perform a screen. I indicated that for at least the past several years, my right ankle has been tighter than my left into dorsiflexion (there is a several centimeter difference when I perform the test above). In testing this prone, he reported that it was not a significant difference, and had me then perform step-downs. This was easy on the left, but nearly impossible on the right, due to my inability to dorsiflex and the resultant increased stress on the knee and hip. I did not want to debate with the course instructor, but ever since he demonstrated the inability of the prone dorsiflexion test to pick up functionally important differences in dorsiflexion motion, I have placed greater importance on including this test in my lower extremity screen. I have always measured the distance to the wall, but given the excellent correlation shown in this study, I may have to pull out our inclinometer and save myself a few steps.
Orthopedic Physical Therapy Research 