Increase Leg Strength With Squats

Build Muscle in Your Lower Body

By Michael J. Rudolph, Ph.D.
Senior Science Editor

The squat is the ultimate leg-building exercise, possessing the unique ability to stimulate massive muscle growth of the lower body while also enhancing athletic performance.¹ Because of the remarkable capabilities and lofty status associated with the squat, it has become widely regarded as a supreme test of lower-body strength – making it an integral component for the strength athlete such as those who compete in the sport of powerlifting.² The sport of powerlifting often involves the use of supportive equipment such as the squat suit. Squat suits are made from very tight material that provides resistance during the downward phase of the movement, while also providing stored elastic energy that is released at the bottom of the movement – aiding the lifter through the upward phase of the lift, which ultimately facilitates the use of heavier weight.

While there has been debate as to whether the powerlifter and non-powerlifter should use the squat suit, there is no argument as to its effectiveness, which has been proven by many powerlifters during many powerlifting competitions throughout the years. However, there has been no scientific data to substantiate these claims, until recently. A few studies support the prudent use of the squat suit, as it not only improves squat performance but also reduces the likelihood of certain types of injury.

Reduced Likelihood of Spinal Injury

Depending on the amount of weight being lifted during the squat, the spine can be placed under an excessive amount of compressive force by leaning too far forward and compromising spine position. Excessive spine flexion caused by too much forward lean during the squat movement has been shown by Fry et al.³ to generate extreme spinal shearing forces that substantially increase the possibility of spinal injury. In addition, overextending the spine to prevent forward knee movement during the squat will also increase possible injury of the spine. Demonstrating this was a study by Dolan et al.⁴ where they confirmed that even a slight increase of only 2 degrees in spine extension from the neutral position notably increases spinal compressive forces by approximately 16 percent. Because the spine is apparently extremely vulnerable to excessive flexion and extension during the squat, it is sensible to maintain a neutral spine throughout the entire squat movement. Since the results from these studies were found while performing the squat without the use of a squat suit, conceivably the use of a squat suit will limit excessive spinal flexion and extension, supporting a more neutral spine position and thus reducing the likelihood of spinal injury.

Increased Squatting Efficiency and Power

A previous study by McLaughlin et al.⁵ found that highly trained powerlifters performed the squat movement more efficiently with less forward movement of the knee when compared to a less skilled group. This significant difference in movement between these two groups contributes to the considerable difference in strength performance, as a study by Fry et al.³ showed that reduced forward displacement of the knee during the squat increased the use of the hip and gluteus maximus muscle groups, significantly increasing force production. Because the squat suit restricts forward knee movement during the squat, the use of the suit should also increase recruitment of these larger and stronger muscle groups, thus enhancing strength and power during the squat.

In order to investigate the squat suit’s influence on performance, a study by Blatnik et al.⁶ looked at the influence the squat suit had on the performance of eight male powerlifters who performed the squat at 80 percent, 90 percent and 100 percent of their one-repetition maximum with and without a squat suit. The most important finding of this study was that squatting with the squat suit elicited higher velocity and power during the concentric or upward phase of the squat, while also decreasing the amount of knee vertical displacement. This finding illustrates that the squat suit confined the lifter to a more optimal squatting motion throughout the movement – activating the larger muscle groups, which resulted in greater performance.

Knee Wraps for Improved Performance?

The benefit from using knee wraps while squatting has also been heavily debated. While using knee wraps increases support and spring at the bottom of the squat, enabling the use of heavier weights stimulating greater muscle growth, others believe the use of knee wraps prevents complete muscle and strength development while increasing the chance for injury. However, research by Lake et al.⁷ suggests that the cautious use of knee wraps can be good for squat performance and muscle growth. In this study, they looked at the squatting performance of 10 men with and without knee wraps. The key finding from this study being that the elastic properties of knee wraps increased mechanical output, allowing for the use of heavier weights – yet altered squatting technique, which may increase the likelihood of knee injury. Taken together, these two opposing details suggest that knee wraps are beneficial for squatting performance and lower body development, but should be used preferentially when lifting weights at very high intensity levels.

In summary, while wearing squat suits and knee wraps gives one the ability to handle heavier weights during the squat – leading to greater muscle growth – they should be used with great caution. This is because their use has been shown to dramatically alter squatting technique, potentially creating debilitating forces on susceptible areas of the body, which could cause injury. In addition, the ability of the squat suit and knee wrap to absorb forces during the squat may diminish the workload normally put on the muscle, which could diminish the muscle-building effect that normally occurs from intense squatting workouts that put tremendous stress on the muscle. All things considered, the prudent use of squat suits and knee wraps can be extremely valuable for squatting performance and lower body development when intelligently employed.

For most of Michael Rudolph’s career he has been engrossed in the exercise world as either an athlete (he played college football at Hofstra University), personal trainer or as a Research Scientist (he earned a B.Sc. in Exercise Science at Hofstra University and a Ph.D. in Biochemistry and Molecular Biology from Stony Brook University). After earning his Ph.D., Michael investigated the molecular biology of exercise as a fellow at Harvard Medical School and Columbia University for over eight years. That research contributed seminally to understanding the function of the incredibly important cellular energy sensor AMPK – leading to numerous publications in peer-reviewed journals including the journal Nature. Michael is currently a scientist working at the New York Structural Biology Center doing contract work for the Department of Defense on a project involving national security.

References:

1. Escamilla RF, et al. Effects of technique variations on knee biomechanics during the squat and leg press. Med Sci Sports Exerc 2001;33(9): p. 1552-66.

2. Escamilla RF. Knee biomechanics of the dynamic squat exercise. Med Sci Sports Exerc 2001;33(1): p. 127-41.

3. Fry AC, Smith JC and Schilling BK. Effect of knee position on hip and knee torques during the barbell squat. J Strength Cond Res 2003;17(4): p. 629-33.

4. Dolan P, et al. Dynamic forces acting on the lumbar spine during manual handling. Can they be estimated using electromyographic techniques alone? Spine (Phila Pa 1976) 1999;24(7): p. 698-703.

5. McLaughlin TM, Dillman CJ and Lardner TJ. A kinematic model of performance in the parallel squat by champion powerlifers. Med Sci Sports 1977;9(2): p. 128-33.

6. Blatnik JA, Skinner JW and McBride JM. Effect of supportive equipment on force, velocity, and power in the squat. J Strength Cond Res 2012;26(12): p. 3204-8.

7. Lake JP, Carden PJ and Shorter KA. Wearing knee wraps affects mechanical output and performance characteristics of back squat exercise. J Strength Cond Res 2012;26(10): p. 2844-9.

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