How deep should you squat? The effect of squat depth on muscle activity

(10-22-2013) Proper technique during an exercise is veryStrongman squat important for good training results. This especially holds true for free weight exercises such as the squat. An important part of exercise technique is the Range of Motion (ROM). To see what the effect of squat depth is on muscle activation during the squat exercise, researchers performed the following study.

What did the researchers do?

In total 10 men and 10 women were recruited all of which had at least 4 years of strength training experience. The subjects were required to perform two different squat varieties. The Parallel Squat which requires the knee angle to be at 90 degrees at the lowest point, and the Partial Squat which requires a knee angle of only 135 degrees at the lowest point (less deep). Testing measurments were done with a load corresponding with the maximum amount of weight with which the subjects could perform 10 repetitions (10RM). During measurements 6 repetitions were done with this load. The load was higher in the Partial Squat compared with the Parallel Squat (see table below). Muscle activity was measured using EMG electrodes on the m. Rectus Femoris (front upper leg), m. Biceps Femoris (rear upper leg), m. Erector Spinae (lower back) and the m. Gastrocnemius (calves).

What were the results?

The results of the study are depicted in the table and figure below.

10 RM Squat    Weight (kg)
Parallel Squat 51,2
Partial Squat 78,4


Effects of squat depth on muscle activity

Figure 1: Muscle activity in mV in different variants of the squat exercise.












Both the m. Rectus Femoris and the m. Erector Spinae were significantly more active in the Parallel Squat exercise compared with the Partial Squat. No differences in muscle activation between the two squat variants were found in the m. Biceps Femoris and m. Gastrocnemius.

What did the researchers conclude?

The researchers concluded that the Parallel Squat was more effective to increase maximum strength in the lower body than the Partial Squat, despite the fact the first exercise does not allow as much weight to be added. In addition the researchers conclude that the increased activation of the lower back can help strenghten it. This might reduce risk of injuries during other exercises since the lower back muscles play an important role in stabilizing the trunk.

What does this mean for me?

Performing the Parallel Squat is more effective than the Partial Squat when the goal is increasing muscle strength and muscle size. Making a larger movement is vital when you want to maintain or even increase maximum range of motion. In addition Parallel Squat is safer as a result of lower weights used and increased muscle activation in stabilising muscles such as the m. Erector Spinae. So how deep should you squat? In conclusion: when your range of motion allows, it is both safer and more effective to perform a deeper squat to where the upper leg is parallel to the floor. Partial squats are less effective.

See also:

-Compound vs isolation exercises


-Gorsuch, J., Long, J., Miller, K. et al. The Effect of Squat Depth on Multiarticular Muscle Activation in Collegiate Cross-Country Runners. Journal of Strength & Conditioning Research 2013, 27,9, 2619-2625.