Who SHOULD NOT use a traditional back squat?
Those in pain
Let us start with the obvious. If squatting with a bar on your back causes significant pain, you should not be back squatting. Repeat this statement using any other exercise and you get the same answer. Whilst minor pain isn’t always an issue, pain during an exercise is rarely, if ever, necessary and it is extremely detrimental to motivation and performance. There are always ways that we can modify an exercise to reduce or eliminate pain, whilst training for the same outcomes. In most cases, minor pain will be a reflection of mobility limitation, weakness and/or overuse (usually a combination of all) and therefore a thorough examination of all relevant muscles and joints is required before deciding on the best course of action.
Those with mobility limitations
There is a certain amount of mobility that one must possess to be able to squat without disfunction. Limitations at the shoulder, hip or ankle can cause a host of up or down-stream issues in common areas such as the lower back and knee. Often times you may need to work specifically on mobility in the 3 key areas before you are able to get in a comfortable squat position. If there are long-term limitations to mobility such as shoulder surgery, you may find that using an alternative variation such as a safety squat bar can allow you to continue working on your prime movers (quads and glutes), without placing detrimental stress on the recovering area.
Those with anatomical limitations
Whilst many mobility issues can be alleviated through specific training, many people are faced with anatomical limitations that inhibit their ability to perform a picture-perfect, full-range squat. An example is a person that has extremely long femurs (upper leg) and limited ankle range of motion. Their squat is going to look more like a hip hinge, than a squat. This is where it is important to step back and have a think about WHY you are performing the squat. If you are using a squat to try and develop quadricep strength through a full range of motion, a traditional squat will not be the answer for this specific person. Again, the only reason you HAVE to use the squat is if it is used within your competition.
Those with muscle imbalances
The squat is a bilateral exercise, it requires the use of both sides of the body. As humans we are naturally asymmetrical, meaning that for 99% of us, we are stronger and more coordinated on one side of the body. Significant strength differences between the lower limbs can cause a heavy reliance on the dominant leg during bilateral exercises. Not only will this continue to widen the strength gap, but it can also lead to dysfunction in other areas of the body. It is important to recognise any major strength differences and work on unilateral exercises such as a single leg squat before progressing into heavy bilateral squats.
Those with poor motor control
By now you have probably got the idea that position is everything. How a squat is performed will determine what is actually gained from its inclusion in an exercise program. For young children, growing teenagers and many sedentary adults, coordination isn’t always a strong suit. Before participating in any weight-loaded exercise, a person must be proficient with their own bodyweight. It is never a good idea to place weight on the back of someone who cannot perform a bodyweight squat with control through a full range of motion. Mobility and coordination should always come before load!
Those with weak supporting muscles
Most people would agree that the squat is an exercise used mainly to develop the quadriceps and the glutes. So what happens when the strength of the spinal erectors is the reason you can not lift any more weight or perform any more reps? Are your quads and glutes really getting the stimulation they need from this exercise? The answer is probably not. In this case, it could be beneficial to perform an exercise such as the leg press for quad and glute strength whilst using specific back exercises to build up the erector muscles. Alternatively, if you really want or need to work on your squat pattern, you could continue to squat (improving the skill component) whilst using accessory exercises to strengthen your weak areas.