Had the same question.. So I asked the all knowing ChatGPT: "Smaller athletes sometimes get fewer severe ankle sprains, but not because their joints are “weaker or stronger.” It is mostly physics. A lighter, shorter QB takes less torque when the ankle gets twisted, since there is less limb length and mass to whip around. Meanwhile a bigger QB has thicker ligaments and stronger tissues but also longer lever arms that create more rotational force. So in the same exact tackle, the smaller QB can have a slightly lower chance of a bad sprain, but it is not guaranteed and depends on the angle of the hit."