SPEAKER_03 2:52–6:19
In the physio world, when testing a muscle like the glute medius, they use a straight plane representation. They think glute medius performs hip abduction because they're using an old school dead guy straight plane representation of what a muscle can do. Now, what we know is that if you move the extremity away from midline in a lateral representation, you're producing a late ER position of the hip. Under that circumstance, the muscle in question is oriented to produce force in IR, and we're asking them to produce force in ER. When they push down on the leg, it collapses, and they conclude the glute is weak. But it's not that the muscle is weak; it's in a position where it cannot produce force in the direction being tested due to its orientation. The test itself is fine, but the interpretation is wrong. They're looking at structural reductionist representations, viewing muscles as separate entities that behave separately. In reality, everything works together in a positional representation. They might say you have an unstable hip, pelvic instability, or weak hamstrings, but essentially it's about a muscle being incapable of producing force in a specific position. For example, if you anteriorly orient the pelvis sufficiently, it's difficult to put the hamstrings in a position to produce force. This derives from historical manual muscle testing approaches, like Florence Kendall's, which graded muscle activity on a five-point scale and used isolated representations of muscles in certain positions. Additionally, they often test in these ER-like weaker positions, making it inherently difficult to produce force regardless.
muscle testinggluteus mediusbiomechanicship mechanicsphysiotherapy assessment