From Charles Poliquin Live
The squat is a killer exercise that gives you back significantly more than you put into it in terms of strength and body composition gains. A recent analysis in the Journal of Strength and Conditioning Research provides some guidelines for designing squat programs to get the most out workouts:
1) Stance width in the squat has a moderate effect on muscle activation in the lower limbs. A very wide stance width that is twice the width of the hips activates the glutes and adductors much more than a hip-width stance.
Rotating the feet out to 30 and 50 degrees will work the adductors even more, and muscle activity is greatest during the bottom phase of the squat in flexion and extension.
2) Compared to altering your squat stance, using heavier loads has a much greater impact on muscle activity. For example, a study that compared hip-width stance with stances that were 150 percent and 200 percent of hip width showed that muscle activation in the quads increased significantly as the load increased to 70 percent of the 1RM—the heaviest load tested.
A second study found that when trainees did squats with a heavier load of 75 percent of the 1RM the activated the quads 20 percent more and the adductors 28 percent more than when they used a lighter 65 percent load, regardless of stance width.
3) Full squats are superior to half or quarter squats. In a comparison of squats to parallel and half or quarter squats, muscle activation is highest in the last phase of the descent and first phase of the ascent. In simple terms, your muscles are working hardest as you go from parallel to a deep squat and vice versa.
The reviewers provide sage advice, writing, “partial or quarter squats will result in reduced muscle activation of the prime movers and therefore arguably produce an inferior training effect in comparison to parallel or full squats.”
4) One study found that deep squats were much more effective in increasing jump height than the partial-range squat. Full-range training with a heavy load is essential, but there is a time and place for partial-range squats if you want to challenge the strength curve and lift a really heavy weight that would be impossible in the full-range.
5) To train the abs and lower back, best results will come from progressively using heavier loads. Traditional exercises such as the squat and deadlift are best for training the abs and lower back.
6) Unstable surfaces such as balance disks appear to activate the quad muscles more (greater EMG activity) but lighter loads must be used, and strength and power gains are compromised. Therefore, unstable surfaces should be avoided when training for strength, power, or speed.
7) The free barbell squat activates the quads much more than a Smith machine squat. One study showed greater activation from the free barbell squats by 26 percent in the biceps femoris, 34 percent in the gastrocnemius, and 49 percent in the vastus medialis over the Smith squat using an 8RM load. The ab and lower back muscles were also more engaged in the free squat.
8) Only one study compared EMG with and without weight belts in the squat. No significant difference was found in muscle activity, but the weight belt trial was performed significantly faster, resulting in greater power output. The reviewers suggest weight belts should generally be avoided because, despite the greater power output, they will undermine the training effects of slower, controlled heavy squatting.
This is the take away point of this review: There’s a time and place for variation (sometimes you might want to trigger more growth hormone with a lighter load and higher reps, or do super heavy partial-range squats), but the core of any squat program should use a ground-based, heavy, free barbell full squat.
Clark, D., Lambert, M., et al. Muscle Activation in the Loaded Free Barbell Squat: A Brief Review. Journal of Strength and Conditioning Research. 2012. 26(4), 1169-1178.