Strength Isometric Test: Supine Hip Internal Rotation

To test supine hip internal rotation (IR) isometric strength with a Muscle Meter, you can follow these steps:

1. Have the client adopt a supine position lying down on a massage table or mat. Ask the client to bring one of their hips up to 90 degrees.
2. While ensuring the client keeps their knee directly over the center of their hip joint, have the client rotate their foot away from their body. Doing this will allow the client’s hip to internally rotate. 
3. As this is a rotational assessment, the Measurz app will utilise the transverse plane feature of the inclinometer. Thus, the starting position of the smart device is critical. The smart device should be resting at 0 degrees, ideally on top of the midway point of the client’s tibia.
4. Once the client has achieved their maximal level of hip internal rotation, press the pause/play, followed by the save buttons to view the client’s results.
5. This test can also be performed passively, by assisting the client to achieve extra range of motion. Should this be selected, please record this in the notes section and use it consistently. NB: Aiming for a result of at least 30 - 40 degrees of hip internal rotation.

Some studies have reported normative data for hip internal rotation isometric strength using a muscle meter in units of force, such as Newtons or pounds. For example, one study of healthy adults aged 18-50 years found that the average peak force for hip internal rotation isometric strength was approximately 33 Newtons for men and 24 Newtons for women (Kawczynski et al., 2020). Another study of healthy young adults aged 18-30 years found that the average peak force for hip internal rotation isometric strength was approximately 49 Newtons for men and 35 Newtons for women (Katz-Leurer et al., 2009).

Other studies have reported normative data for hip internal rotation isometric strength using a muscle meter in units of torque, such as Newton meters or pound-feet. For example, one study of healthy older adults aged 65-89 years found that the average peak torque for hip internal rotation isometric strength was approximately 10 Newton-meters for men and 7 Newton-meters for women (Molloy et al., 2010).

References:

1. Hislop HJ, Montgomery J. Daniels and Worthingham's Muscle Testing: Techniques of Manual Examination and Performance Testing, 9th ed. Philadelphia: Saunders/Elsevier, 2013.
2. Mentiplay BF, Perraton LG, Bower KJ, Adair B, Pua YH, Williams GP, et al. Assessment of lower limb muscle strength and power using hand-held and fixed dynamometry: a reliability and validity study. PLoS One. 2015;10(10):e0140822.
3. Youdas JW, Krause DA, Hollman JH, Harmsen WS, Laskowski E. Validity and reliability of strength measures from the Myotest and Jamar hand-held dynamometers in adults. J Hand Ther. 2009;22(3):266-273.
4. Bohannon RW. Hand-held compared with isokinetic dynamometry for measurement of static knee extension torque (parallel reliability of dynamometers). Clin Phys Physiol Meas. 1990;11(3):217-222.