The way muscles are thought to work when they're still doesn't seem to match how they actually perform when moving your wrist continuously — what we know from static tests might not apply when things are in motion.

What we've found so far suggests that the isometric length-tension curve — which describes how muscle force changes with length when the muscle is not moving — may not accurately predict wrist muscle torque during dynamic movements. Our current analysis is based on one assertion from the evidence we've reviewed. The evidence we've reviewed leans toward the idea that muscle behavior during steady, controlled contractions doesn’t fully reflect what happens when the wrist is in motion [1]. In other words, the force a wrist muscle produces when held at a fixed length might not tell us much about how it performs when actively moving, like during gripping, turning, or lifting. This could mean that models based on static muscle tests have limits when applied to real-world, moving tasks. We only have one assertion to draw from so far, and no studies or claims that contradict it. Still, this doesn’t mean the pattern is solid or proven — it just means that what we’ve seen up to this point points in a certain direction. There isn’t enough evidence to say how strong this mismatch is, or whether it applies to all wrist muscles or specific movements. Our analysis remains limited by the small amount of evidence available. As more studies are reviewed, our understanding could change. We don’t yet know whether adjusting training or rehabilitation programs based on dynamic muscle behavior would lead to better results. Practical takeaway: If you're relying on static muscle tests or theories to predict how wrist muscles work during movement, keep in mind that real motion might not follow the same rules.