Back squats are an incredible strength building exercise. Under proper form the movements is very safe and recruits muscles from the entirety of the body to make the lift successful. The 5×5 scheme has been found to be the best for developing strength and endurance. If you recall, strength + endurance = Power and power is the measure we use in CrossFit to gauge our progress. Everything we do in CF is quantifiable, meaning we can attach a method of measurement for the purposes of gauging fitness to all exercises in one form or another.
A few things to consider with the squat. Legs should be under the hips, toes turned out about 30 degrees. When descending, the knees should track over the toes and even extend a bit beyond the toes dependent upon bar position style and personal anthropometry. The back should maintain an angle that will keep the bar directly over the center of the foot on the way down and back up. The bar’s placement is key too and there are two ways to do it, no real right or wrong. I have done both and prefer the low-bar position.
A high bar, resting on the traps and across the rear of the delts, will force the lifter to maintain a more upright posture. Under heavy load, as the lifter tries to keep the bar over the foot, many will find the back angle becomes difficult to maintain. This is partly due to the high bar position and as the lifter compensates to keep the bar over the mid-foot, the load at the top of the spine can place a lot of shear force on the back due to the lever arm it becomes. That being said, Oly lifters prefer the high bar position over a low bar position due to the upright posture which more closely translates to the Oly lifts and the posture needed to complete them.
The low bar position rests a couple more inches down the back, right below the upper edge of the scapula. There’s a nice little pocket there that the bar can rest in, pinned in place by your arms wedging it tightly to the back. This position keeps the bar, and thereby the weight, lower on the back. This means less of a lever arm and less torque on the lower back. The bar maintains an easier position over the mid-foot with less compensation by the back in maintaining the proper body angles and bar alignment. This allows you to squat more weight, which is why it is favored amongst power lifters. I did not believe it until I tried it. It was also easier on my low back. It does tend to be a bit uncomfortable on the scapula for long periods of time under heavy weight, but if you are a total Nancy, you can pad it with a towel. I would not recommend using a foam pad as it can spin/slip and the bar will zip down your back at high speed. Your shoulders tend not to like this violent tearing motion, so avoid it.
Also, a neutral head posture is important. I don’t know where the stupid “look at the ceiling” thing came from, but that is murder on the shoulder girdle and cervical column. You are seriously putting some unnatural angle on the spine and under load, this is no bueno. Instead, you should be looking at a spot about 7 feet in front of you on the floor or at the most, directly ahead. This maintains a neutral head position and less bad things going on in the spine.
As for the argument about squats being had for the knees, well those people are right – if you are doing squats above parallel. When you fail to squat to a point below parallel, the adductors, quads and other supporting muscles start to exert a tremendous amount of pulling force on the knee. In a complete, ass-to-ankles squat, this force is compensated and relieved by the hamstrings which actually are what provides the bulk of driving force from the bottom, along with the glutes. If you are doing good squats at depth, you are getting total leg recruitment – quads, glutes, hams and all their friends. If you only go halfway, the only thing really working is the quadriceps. There is a lot more going on here, but that’s the condensed version of why squats are NOT bad for your knees and why we need to go below parallel.
Be smart, don’t get hurt here. Work up to a heavy, yet manageable weight that allows you to get in deep while still maintaining a good lordotic arch (low back). If your hams are tight, this arch will go away as you get to parallel. If this happens, don’t try to be the hero and squat a bunch of weight below parallel since the lack of nice back posture will cause things to hurt….bad. Instead, I would rather someone works a light weight to a safe depth and make improvements from that point on. In fact, I will not give my clients any weight to speak of until their air squats are perfect everytime. You should do the same. Squats also kick out a strong neuroendocrine response, and that’s important on so many levels. Have fun, work hard and GET SOME!