Bodybuilders typically perform the squat with their thighs parallel to the floor in the bottom position. Olympic weightlifters, on the other hand, usually do what are known as full squats, where the thighs are well below parallel with the floor, or what some call “ass-to-floor” (deep) squats.
Squatting to parallel is the safest and most effective way to squat. Some experts believe that going any deeper than parallel in the squat can lead to knee injuries. Plus, most guys lack the flexibility to squat any deeper, anyway.
Parallel squats are not full range-of-motion (ROM) squats. Full range of motion is only reached when a squat passes parallel level. To get the most out of a muscle in the areas of strength and hypertrophy, you should use full ROM movements at least some of the time.
Researchers from the University of Alberta, in Canada, calculated what is known as the “net joint movement” (NJM) of the ankles, knees, and hips during both squats to parallel (about 105 degrees of knee flexion) and full ROM squats (about 120 degrees of knee flexion). This technique is used in biomechanical studies to determine the minimum muscular torque required by the muscles that move that joint. In other words, the NJM of the knee joint determines the amount of force supplied by the quads. The more force, the more muscle activity and the stronger the muscle can get; and the more muscle activity involved, the greater the potential for muscle growth. The results: The NJM of the knee joint was approximately 20% greater during full squats than during parallel squats.
Similar results regarding NJM of the knee joint during full squats versus parallel squats were also reported by Swedish researchers in a 1996 study.
And a study presented at the 2008 Congress of the European College of Sport Science reported that subjects performing full squats for 12 weeks had a significantly greater increase in thigh muscle growth compared to those doing shallow squats.
As far as safety of the knee joint goes, several long-term studies suggest that doing full squats does not have a negative effect on knee ligament stability or place the knee joint at risk of injury. Plus, ROM squats reduce stress on the spine.
VERDICT: FULL SQUATS
Based on these studies, it does make sense to try to increase your ROM in the bottom position of the squat for better strength and muscle growth.
To start going deeper with your squats, begin your leg workouts with two to three sets of lightweight squats, trying to go as deep as possible. This will serve as both a warmup and a method for increasing your ROM in the squat. Follow this with your typical squat workout with heavy weights, not worrying about how far past parallel you go down. Over time, you’ll find that your heavy sets of squats are getting deeper and your leg strength and size are becoming greater.
Also, to help you get deeper in the squat, work on your flexibility in your quads, hamstrings, glutes, and calves. Static stretching (hold-and-reach style) works well for this, but be sure to do this AFTER your workouts, as research shows that doing static stretching before workouts can limit muscle strength and power.
You can also work on increasing your ROM in the bottom of the squat by using box squats that get progressively lower over time. If your gym doesn’t have a variety of box sizes (most don’t), you can use an adjustable decline bench instead. Start with a flat bench, then progressively increase the decline until you feel comfortable going deep in the squat with a loaded barbell on your back. You can also do this with a decline bench that’s not adjustable simply by standing farther back for higher squats then progressively moving forward on the bench to go lower. You may also want to consider wearing shoes that have a raised heel, such as Olympic weightlifting shoes (or even work boots). Or you can place a two-by-four or weight plates under your heels. This will reduce the forward bend of your shins and help you go deeper.