Ever copied a lifter's squat form and felt something was just... off? Your skeleton might be why.
Every joint works like a lever, and the length of that lever, called the moment arm, varies from person to person. At the knee, the patellar tendon's moment arm averaged about 46 mm in one study, but males measured 5 to 10 mm longer than females (Dandridge et al., 2022). At the ankle, healthy participants had Achilles tendon moment arms roughly 4 to 5 mm longer than people with Achilles tendon injuries, even though everyone was matched for height and weight (Khair et al., 2026). That small difference may change how hard the tendon has to work.
Before you blame your proportions for every sticking point, though: in a small study of 11 trained men, limb lengths explained very little about deadlift mechanics (Keith et al., 2023).
The takeaway? Structure matters, but it isn't destiny. Experiment with stance width and foot angle, and pick the setup that feels strong and smooth for your body.
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Reference: Dandridge, O., Garner, A., Amis, A. A., Cobb, J. P., & Arkel, R. J. (2022). Variation in the patellar tendon moment arm identified with an improved measurement framework.Journal of Orthopaedic Research, 40(4), 799-807. https://doi.org/10.1002/jor.25124
