No. Butt wink is not a useful term. But if you are referring to lumbar flexion in the bottom of the squat, then that decreases the tension on the hamstrings.
No. Butt wink is not a useful term. But if you are referring to lumbar flexion in the bottom of the squat, then that decreases the tension on the hamstrings.
From that I take it that most of the people on this website aren't getting the full stretch reflex then. I must admit that when I go into a full squat, I can't feel it.
You how you know when you've done it correctly?
The bar feels like it flies up on the ascent. It's almost as if the load was lighter, but it wasn't; you had just prepared the system to engage more muscle to lift the weight. That's what the stretch reflex is all about; a muscle under tension will want to contract harder.
Try this: slow down just a touch. Because you have to consciously use your muscles to lower the bar, as opposed to letting gravity do the work, you'll prime the springs to engage.
I would also throw in that a lack of stretch reflex is probably more of a lack of enough isometric contraction of the spinal erectors when there are no obvious form issues that would point to the hamstrings. Satch makes a good point, too: slow down. Something must relax to descend quickly in the squat, and there is nothing about that relaxation that is desirable/good for the squat or lifter.