Strength Isometric Test: Ankle Inversion

Testing ankle inversion isometric strength with a muscle meter can be done using the following protocol:

1. Have the client adopt a supine position, lying down on a table with their shoes and socks off. 
2. Ensure the foot being tested starts in a neutral position with a small amount of degrees of ankle eversion. 
3. To increase comfort levels of the client, place a small towel or soft lining underneath the surface of the foot toward the medial side where the Muscle Meter will be placed.
4. Prior to proceeding with this protocol, it is recommended that the practitioner assist the client while applying downward pressure to the client’s lower leg. This will ensure the ankle joint is truly isolated throughout this test. 
5. To promote the most accurate and reproducible results, it is critical that the practitioner keeps Muscle Meter as close as possible to their body throughout the test. This will make it much easier for the practitioner to maintain maximum leverage while expending minimal energy themselves. 
6. Once set, queue the client to invert their ankle inward as best they can, holding for 2-3 seconds to achieve peak force. Hit save on the Measurz app, and compare the results to the other side.

One study by Wikstrom et al. (2010) reported normative data for ankle inversion strength using isokinetic dynamometry in healthy young adults. The study found that the mean peak torque for ankle inversion was 46.9 Nm for males and 28.5 Nm for females.

Another study by Bohannon and Larkin (1985) reported normative data for ankle inversion strength using manual muscle testing in healthy young adults. The study found that the mean score for ankle inversion strength on a scale of 0 to 5 (with 5 indicating normal strength) was 4.9 for males and 4.8 for females.

References:

1. Leung, J., Moseley, A. M., & Grivas, T. B. (2011). Electrogoniometric and dynamometric assessment of ankle dorsiflexion after a proprioceptive neuromuscular facilitation intervention. Physical Therapy in Sport, 12(2), 71-79.
2. Nester, C. J., Jarvis, H. L., & Jones, R. K. (2007). Bowler I et al. Inter-session reliability of ankle isometric, isotonic and isokinetic strength and power measures. Journal of sports sciences, 25(8), 905-913.
3. Samson, K. M., & Ng, J. (2003). Ankle invertor muscle strength and dynamic balance. Journal of Orthopaedic & Sports Physical Therapy, 33(8), 407-414.
4. Zinder, S. M., Granata, K. P., & Padua, D. A. (2007). Reliability of a handheld dynamometer to measure isometric ankle inversion and eversion strength. Journal of Sport Rehabilitation, 16(1), 64-75.