Introduction: Muscle strength has been incorporated in the outcome assessment tools of many joints such as the shoulder and the hand. The purpose of this study was to examine the reliability and therefore the suitability of muscle strength around the ankle joint to be incorporated in foot and ankle assessment tools.

Participants: Sixty-nine healthy volunteers participated in this study (35 females and 34 males); the average age was 35 years (range: 21 to 71 years).

Methods: Three measurements of plantar flexion strength and of dorsiflexion strength of each ankle were performed using the Nottingham Mecmesin Myometer. Measurements were repeated at 2 weeks interval. The averages from first and second occasions were statistically compared.

Results: The average plantar flexion strength was 20.2 kg (range 11 to 41 kg). The average dorsiflexion strength was 14.7 kg (range 7 to 26 kg). The ninety five percent limits of agreement were −5.9 (29%) to +5.2 (26%) kg for the planter flexion and −4.9 (33%) to +5.2 (35%) kg for dorsiflexion.

Discussion/Conclusion: Both plantar flexion and dorsiflexion strengths showed repeatability. Nevertheless, the reliability of planter flexion is higher. Furthermore, this reliability is similar to those of grip strength and shoulder abduction strength. Hence, we advise to incorporate ankle planter flexion strength in foot and ankle outcome assessment tools.