You can certainly squat and deadlift in the same workout safely, but there are some fine points you need to consider in order to avoid problems.
First, you should never squat after you deadlift.
The deadlift fatigues your whole back, and form always suffers when you squat with drained spinal erectors. If you choose to do so, your back will give up way before your legs have been impressed, which would takes away from the primary reason people squat – to develop a strong lower body.
On the other hand, deadlifting after squats is way more forgiving, although you can still run into hip and back issues and except to have less than optimal deadlift experience. However, you can still do very well and many people choose to squat and deadlift on the same day to mimic the conditions at a powerlifting competition, where the deadlift is done last.
This is also one of the reasons powerlifting purists tend to consider records set at one lift meets less impressive. There is a big difference between deadlifting at the end of a three lift meet and deadlifting first in a pull only competition.
If you are considering squatting and deadlifting in the same workout, you have to do a pushing upper body exercise in between. Movements such as the bench press, dips, push-ups, dumbbell press and the overhead press are all fine. What you should avoid are pulling and biceps exercises. Deadlifting with tired biceps and pulling musculature is no fun nor safe.
The main reason to put an upper body exercise between the squat and the deadlift is to give your body (hips and back) and CNS time to recover for the caveman party that’s about to happen at the end of your workout.
What are the benefits of doing squats and deadlifts in the same workout?
There are two main reasons to squat and deadlift in the same workout – to save time and to mimic a powerlifting meet.
If you find yourself in a situation where you cannot go to the gym multiple times a week, workout compression may be required, and this is one of the ways to do it. At the same time, if you are a powerlifter, replicating the meet conditions will prepare you better for contests. A popular powerlifter under the name of Dave Jacoby used to train the same way (all lifts in one day) because he worked as a truck driver while competing.
What are the benefits of spiting squats and deadlifts into different workouts?
The main benefit is that you can do the exercises when you are fresh and have greater focus. When you know that heavy deadlifting is waiting for you at the end of your workout, the whole training sessions becomes way more stressful. Many people who have reached more advanced numbers find splitting the two lifts into separate dedicated workouts much more forgiving.
Another benefit is that you can accumulate more deadlifting volume. When you are deadlifting and squatting in the same workout, the deadlift is done for just one set. If you do the lift separately, you can add a little more volume.
If you are going to squat and deadlift in the same workout, don’t neglect the following:
never deadlift before squats;
do an upper body pushing exercise in between the squat and the deadlift;
don’t deadlift for more than one working set;
don’t do pulling exercises of any sort before your deadlifts;