When it comes to training for strength and muscular growth for your legs, you have to take a calculated approach.
First off, your approach has to be progressive, you cannot expect to grow following the same routine week after week. Your body will adapt to this, and eventually your progress will start to stagnate. Ideally speaking, you should be changing your routine around every 3-4 weeks (For intermediate-to-advanced lifters) and 4-6 weeks (For beginner lifters).
Do you best to avoid the comfort zone of using a smith machine to do squats instead of your conventional free standing squat. Important stabilisation factors come into play when doing a free standing squat. Avoid doing anything that makes you feel too comfortable.
First mistake, the smith machine is designed to HELP you when doing any movement within the smith machine. This is due to the springs and tension within the upright stands that assists you during your reps. This tension, takes a huge load off of your legs, especially in your hamstrings and glutes, (remember the squat is 60% hamstrings and glutes, and 40% quad work). So it’s more than likely that you’re compromising the optimal growth within your legs, by using the smith machine.
Second mistake, you lose all the tension within your back when using the smith machine. The squat is basically a full body movement, you engage your core first, (before even starting the squat), which engages and strengthens your Erector spinae muscles (lower back). So again, with the smith machine you are losing the tension within your lower back, and putting a direct load on your Lumbar vertebrae – which could then lead to lower back injuries.
Thirdly, the correct degree of flexion for the squat to engage maximal glute activation is below parallel or just below 90 degrees.
As seen in the pic attached below.
So please, when it comes to the correct technique especially with a complex exercise such as the squat, please make sure you are getting your information from someone who knows what they are doing. Don’t make the mistake by copying someone else’s technique in the gym.
Remember to have fun, set goals and keep progressing toward them in a safe and calculated way.