The most important thing as a beginner is to get the technique down. You need to make sure you have a stable foundation before you start thinking about going heavy, so practise with light weights first. Done properly, these moves are very beneficial, but injuries start to happen when you load with bad form.
The back squat
A back squat is when you are under a barbell loaded with weights and you are squatting to depth – this means that the hip joint is parallel or below the knee joint – and you drive up from the squat.
You will hear a lot of personal trainers say that you should not let the knee track over the toe. But this is a myth! You should let the knee track over the toe. If it doesn’t, you probably have poor ankle mobility; it will also tend to throw the form off.
Deadlifts work all major muscle groups. The goal is to drive the weighted barbell off the floor into a lockout position, and then to bring the weight back down to the floor safely, while remaining in contact with the bar.