Common Form Mistakes #2: Locking knees on the Deadlift

While not a perfect picture, the image above shows the likely outcome of locked knees while deadlifting; a round back from neck to butt. Not pretty and most likely, this guy’s back didn’t feel so great the next day.

When I coach the deadlift, inevitably, first time attempters will lock their knees. This is usually mildly amusing for me as I always take time to physically demonstrate several reps first. As I demonstrate, my knees are soft and bending as my hips push backwards. Luckily, for a first timer, they are only doing bodyweight drills or using an empty bar so the possibility of hurting their back is not really that high. However, I do want to nip this nasty habit in the bud as soon as I can. Locking the knees as you descend on a deadlift is asking for a strained lower back or worse.

Disclaimer: There is an exercise called the Straight Leg Deadlift. However, I do not even feel straight leg deadlifts should be done with perfectly straight legs, i.e. locked out knees. Most coaches agree, a slight bend is beneficial for glute activation and avoiding a strain in the hamstrings or lower back.

Look at the image to the right, now imagine the legs are locked straight. What does that do to the lifter?

Well, if his back remains in the same relative position, the bar has now shifted considerably in front of this lifters center of gravity. What do you think that will do to his lower back as he pulls the bar off the ground? If you said, "Strain it, " good job.

If he locks his knees but somehow keeps the bar near his shins, what do you think happens to his back? Most likely our lifter will look like a question mark from the side, with a big ol' curve from neck to butt as he attempts to keep his legs straight while keeping the bar close to his shins. Sounds painful.

Is there any way you can keep the knees completely locked AND keep the back in the correct relative position AND keep the bar near the shins, aka, your center of gravity?

Yes, and it involves going so light as to make the exercise almost pointless. It is almost as if you are teasing yourself, tempting fate as you wait for the lower back demons to perform their dirty work. Leaving you incapable of bending over to tie your shoes without spasms of pain shooting every which way like lightning emanating from the small of your back.

So relax those knees will ya? Do not lock them. Let them bend as you push the hips backward. This combined action of pushing the hips backward while letting the knees naturally bend as an effect of the hip motion, will keep your lower back safe and allow you to most effectively recruit your hamstrings and glutes. These are the muscles you want as your primary movers during the deadlift.

I will leave you with one last image. Look at the girl below. Nice spinal alignment, flat back, hips pushed backwards and knees naturally soft. I guarantee you she didn’t think about bending those knees as she got into position. But just because she didn’t think about it, doesn’t mean they don’t bend. I cannot say it enough, so here goes one last time; do not lock your knees.