The squat and the deadlift are probably the two most popular exercises that exist. But, how much does the deadlift carryover to the squat (does the deadlift increase your squat?), and what about the opposite, how much does the squat carryover to the deadlift (does the squat increase your deadlift?).
In this article, we’ll be answering these exact questions based on the available evidence.
Table of Contents
First, let’s explore the similarities and differences between the squat and deadlift.
I must note that when I mention the squat, I am referring to the high bar back squat, as this outside of powerlifting, this is probably the most common squat. Moreover, the high bar back squat is the squat used in the research we will be reviewing throughout this article.
That said, much of the information in this article will very much apply to the low bar back squat and front squat. This is simply because there are way more similarities between these squat variations than differences.
Also, when I mention the deadlift, I am referring to the conventional barbell deadlift.
Comparing the Squat and Deadlift
Both movements primarily involve the extension of the hip, knee, and spine.
Therefore, both the squat and deadlift activate similar muscle groups: the gluteus maximus and hamstrings (which primarily extend the hip), the quadriceps (which extend the knee), and the spinal erectors (which extend the spine).
However, the extent to which these muscle groups would be activated would not be identical between the two exercises.
Let’s compare the start positions between the two movements:
Based on research by Swinton et al. at the start of the deadlift, the hips are flexed around 89.8 degrees, while the knees are flexed around 72 degrees.
Based on a different paper by Swinton et al. at the lowest position of a parallel back squat, the hips are flexed around 104 degrees, while the knees are flexed around 120 degrees.
It’s important to note that these numbers are just averages. Moreover, these are from two different studies with different subjects. Your numbers will likely vary from these to some degree. But nonetheless, they do give us a rough estimation of the joint angles in the squat and deadlift.
As we can see, hip flexion is slightly more in the squat (overall, this probably is not significant).
But knee flexion is significantly more in the squat.
The greater knee flexion with the squat means that the overall range of motion the knee joint goes through is greater. This is important because longer ranges of motion with the knee joint are associated with greater overall quadriceps hypertrophy.
On top of the greater knee range of motion with the squat, it also involves a longer moment arm for the knee joint.
The moment arm is simply the perpendicular distance from the line of force (which is typically a vertical line that goes through the barbell with these exercises) to the joint we are looking at.
With all things equal, a longer moment arm means that the muscles that move that joint must work harder.
Therefore, the longer knee range of motion and longer knee moment arm with the squat vs the deadlift means the quadriceps are going to be more involved in the squat.
When comparing the moment arms for lower joints of the spine and hip in both exercises, the deadlift would typically involve a slightly longer moment arm for both. However, I’m not entirely sure if this slightly longer moment arm would be significant.
I think there’s a good probability that the spinal erectors would be more involved with the deadlift vs the squat. Much anecdotal evidence suggests that deadlift taxes the lower back to a greater extent. Moreover, there is evidence that deadlifts result in lower back pain.
This may suggest that the spinal erectors are likely required to be more activated during the deadlift.
With the gluteus maximus (which are involved in hip extension), the deadlift is without a doubt is a great movement for developing this muscle group. However, research suggests that deep squats also significantly hypertrophy this muscle.
Based on this, I think there’s a chance both the squats and deadlift involve comparable high amounts of gluteus maximus involvement (though future research would be needed to confirm this).
The hamstring muscles are also involved in carrying out hip extension. The squat, contrary to popular belief, does not significantly involve the hamstrings. This is because the combined significant knee and hip flexion ultimately mean the hamstrings remain at a fairly constant length throughout the whole duration of a squat.
The lesser knee flexion and the greater stretch of the hamstrings with the deadlift mean that this muscle group is significantly involved.
Okay, so now that we have detailed some of the similarities, and more so the differences between the squat and deadlift, it’s time to move on to the main section of this article: does training the deadlift exclusively increase your squat? Also, does training the squat exclusively increase your deadlift?
In other words, do the squat and deadlift carryover to each other?
Does the Deadlift Increase Your Squat? (And Vice Versa)
To answer this question, we’ll be looking at this great paper by Nigro and Bartolomei.
They split 25 trained men into either a squat group or a deadlift group. The subjects had an average of 3 years of training experience. Moreover, their average deadlift was 135kg, while their average squat was 138kg.
The squat group trained the parallel back squat. The deadlift group trained the conventional barbell deadlift.
Both groups trained their respective exercise 3 times per week for 6 weeks.
The table below outlines the reps and sets used for both groups throughout the 6 weeks:
One-rep max on both the parallel squat and conventional barbell deadlift was measured before and after the training period for both groups.
The squat group increased their back squat one-rep max by 15.2% on average, while they increased their conventional barbell deadlift one-rep max by 5.7% on average.
The deadlift group increased their back squat one-rep max by 6.7% on average, while they increased their conventional barbell deadlift by 17.7% on average.
So, does the deadlift increase your squat? Based on this study, it seems it does, as the group that only deadlifted 6 weeks managed to increase their squat by 6.7%.
Does the squat increase your deadlift? Similarly, it seems it does, as the group that only squatted for 6 weeks managed to increase their deadlift by 5.7%
Of course, these increases aren’t as much as the increases the groups experienced for the exercise they trained. But according to the principle of specificity, these results make sense.
Why Is Their a Carryover Between the Squat and Deadlift?
Unfortunately, the researchers did not dive into the potential underlying mechanisms as to why there was some degree of carryover between the squat and deadlift.
But nevertheless, we can speculate.
Overall, I think the most likely explanation behind the carryover between the squat and deadlift is down to muscle hypertrophy, more specifically of the gluteus maximus and possibly spinal erectors. Note, this is likely why other exercises like the hip thrust, as explored in another article, may also have a good carryover to the back squat.
As mentioned earlier in this article, both the deadlift and squat train the gluteus maximus and spinal erectors to a good degree. Therefore, training either of these exercises would of course grow these muscles.
Hypertrophy of these muscle groups would mean that they can produce greater force (though this is assuming the growth is myofibrillar hypertrophy). This gluteus maximus and spinal erector growth should allow you to be stronger with both the deadlift and squat. This probably explains why the squat and deadlift have some degree of carryover.
A very important consideration is that the stronger you get on the squat and/or deadlift, the carryover between them likely becomes less and less. This likely relates to the principle of specificity.
For example, if you are squatting around 200kg (440lbs), I highly doubt taking 6 weeks off and training the deadlift exclusively would increase that squat (and vice versa).
This is probably because once you are moving impressive weight on either or both of the squat and deadlift, your gluteus maximus and spinal erectors are probably extremely well developed, and the amount of further growth that could occur would be relatively little.
Furthermore, other factors such as coordination and overall technique are important when it comes to getting strong on a particular exercise. When moving impressive weight on either the squat and/or deadlift, taking six weeks off and training one of the exercises would probably reduce your coordination and overall technique on the other exercise, negatively impacting strength.