Analysis of Knee Flexion Angles During 2 Clinical Versions of the Heel Raise Test to Assess Soleus and Gastrocnemius Function

Abstract

STUDY DESIGN: Controlled laboratory study, using a repeated-measures, counterbalanced design. OBJECTIVES: To provide estimates on the average knee angle maintained, absolute knee angle error, and total repetitions performed during 2 versions of the heel raise test. BACKGROUND: The heel raise test is performed in knee extension (EHRT) to assess gastrocnemius and knee flexion (FHRT) for soleus. However, it has not yet been determined whether select knee angles are maintained or whether total repetitions differ between the clinical versions of the heel raise test. METHODS: Seventeen healthy males and females performed maximal heel raise repetitions in 0ࠨEHRT) and 30ࠨFHRT) of desired knee flexion. The average angle maintained and absolute error at the knee during the 2 versions, and total heel raise repetitions, were measured using motion analysis. Participants' kinematic measures were fitted into a generalized estimation equation model to provide estimates on EHRT and FHRT performance applicable to the general population. RESULTS: The model estimates that average angles of 2.2ࠡnd 30.7࠷ill be maintained at the knee by the general population during the EHRT and the FHRT, with an absolute angle error of 3.4ࠡnd 2.5ଠrespectively. In both versions, 40 repetitions should be completed. However, the average angles maintained by participants ranged from -6.3࠴o 21.6ࠤuring the EHRT and from 22.0࠴o 43.0ࠤuring the FHRT, with the highest absolute errors in knee position being 25.9ࠡnd 33.5ଠrespectively. CONCLUSION: On average, select knee angles will be maintained by the general population during the select heel raise test versions, but individualized performance is variable and total repetitions do not distinguish between versions. Clinicians should, therefore, interpret select heel raise test outcomes with caution when used to respectively assess and rehabilitate soleus and gastrocnemius function.