Do full-range of motion heavy squats to train the posterior chain for strength and size. Full-range of motion squats in which you go all the way down so that the hamstring covers the upper calf is one of the best exercises you can perform and they can produce all of the following results: Greater muscle size in the glutes and hamstrings, increased range-of motion in the hip joint, higher vertical jump height, and more strength in the entire lower body.
There’s a time and place for partial range squats, but studies show that you’ll get more out of your efforts by making full-range training a staple, and you’d do well to avoid the box squat. Two recent studies in the Jouranl of Strength and Conditioning Research provide new information to help convince all healthy populations to choose full-range squats.
In the first study, researchers performed a motion analysis to identify the mechanical effort required by the calves, quads, hamstrings, and glutes during the squat at knee angles that ranged from 30 degrees to 119 degrees using loads of 50, 60, 70, 80, and 90 percent of the 1RM. Results showed that the calves experienced the greatest training stimulus when trainees squatted all the way down with the 90 percent load. For the quads, squat depth (95 to 119 degrees of flexion) was most important for optimal training stimulus and heavier loads did not lead to greater effect. For the hamstrings and glutes, the heaviest, deepest squats produced the greatest activation.
Take away the knowledge that full-range, heavy squats give you more return on your investment, allowing you to recruit more higher threshold motor units so you can produce more force. Know that to train the quads, you have to go all the way down, otherwise you may develop structural imbalances, putting you at risk of injury and dysfunction.
This study also provides more data that a full-range squat will help you jump higher since they maximally recruit the posterior chain including the calves. We know from a recent German study that the greatest vertical jump gains will come from full-range squats rather than half- or quarter-range squats, even if the partial squats are trained at heavier loads than the full squats.
A related issue is whether to box squat. In order to put this debate to rest, be aware that a motion analysis of an unloaded sit-to-stand—a similar motion as a box squat—activates the quads much more than it does the posterior chain. And a 2010 study shows that the box squat produces less muscle activation in the quads than a regular squat (presumably a parallel squat was used in this study, but that is not specified).
With the knowledge we have from the first motion analysis study, we know that depth is more important than load to train the quads, meaning that a box squat would never be superior to a parallel squat, since the box squat trains the quads to a lesser degree than the parallel squat, and the parallel squat is already inferior to the full-range squats. Got that? The order of activation from greatest to least for the quads is full-range, parallel, box squats.
A few more reasons not to box squat include the following: it eliminates the stretch-shortening cycle, which is critical for power and jumping ability; the restricted movement pattern changes soft tissue integrity and can produce tightness in the piriformis, which will impair the ability to change direction in sports; and the shins don’t travel forward, which is a pointless way to train since the knees have to pass over the toes when you go up and down the stairs or are playing sports.
McBride, J., Skinner, J., et al. Comparison of Kinetic Variables and Muscle Activity During a Squat Vs. A Box Squat. Journal of Strength and Conditioning Research. 2010. 24(12), 3195-3199.
Bryanton, M., Kennedy, M., et al. Effect of Squat Depth and Barbell Load on Relative Muscular Effort in Squatting. Journal of Strength and Conditioning Research. 2012. Published Ahead of Print.