PART II - Health, Injury Prevention, Longevity
Physicians and athletic trainers often discuss whether or not full ROM squats create too much shear force on the knee. Parallel squats are often recommended over full ROM squats because of knee pressure. Some have even argued that sports rarely require movements deeper than parallel, so full ROM is unnecessary. Generally speaking, athletes and/or persons whom have issues with full range of motion (ROM) squats often have pre-existing knee injuries or utilize incorrect squat technique. Regardless if it's parallel or full ROM, both parties understand that squats are an essential functional exercise. So the question remains, why perform a full ROM squat?
1) Biomechanics of a squat... how it effects the tissue layer, tendons, and ligaments?
Squats result in significant posterior chain development; soft tissue elasticity when performing full ROM; the synchronization of multiple joints; and strength in the tendons and ligaments. On the contrast, lack of movement, short ROM, sedentary lifestyle, chairs, and many other lifestyle habits lead to less elastic tissue and/or miniature adhesions in the fascia tissue layer. Adhesions and tightness in the soft tissue are the most common reasons for muscle strains and tears. Soft tissue impingement results in tendon and ligament tears as well. Therefore, it is imperative that the soft tissue layer of the human body remain elastic. In order to remain elastic one must engage in stretching and full ROM movements. It is imperative that each athlete and person who engages in resistance training performs self-myofascia release therapy (aka "foam rolling) and statically stretches post workout. The other option would be to seek out an ART specialist and/or a sports massage therapist.
2) Injury prevention, elasticity, longevity, health....
Performing full ROM squats have been linked to healthier knees, lower backs, and a stronger core (if performed correctly). Select studies have even shown that full ROM squats are superior in regards to knee health and longevity. Recently, a German study took 10 participants and had one group perform parallel squats and one group perform full ROM squats (5). Each of the participants who performed full ROM squats had zero to minimal knee pain and/or injury over a prolonged period of time. On the contrary, each participant whom performed parallel squats felt knee pain and/or became injured.
Parallel or quarter squats do not utilize maximal flexion, extension, and range of motion of the soft tissue and knee ligaments. The results are less elastic soft tissue, decreased tendon and ligament strength, and underdeveloped hamstrings and glutes. This is in large part to tendon and ligament weakness and soft tissue elasticity.
3) Existing knee problems...
The only individuals who should be precocious while performing full ROM squats are those with major knee issues; knee surgery, significant pain, and/or other major trauma. The ACSM claims that the knee joint undergoes 7.6 times sheer force once the knee joint is past 90˚ parallel. However, full ROM squats will increase tissue elasticity, strengthen the ligaments, break up any scar tissue, and flood the knee joint with vital nutrients. This is the most optimal way to increase knee health. Therefore, it is imperative to slowly progress through ranges of motion until eventually reaching a full ROM squat (even if it's body weight).
According to the NSCA and NASM, the knee joint is part of the endocrine response system to exercise. The endocrine response system contains glands within our body that are related to optimal hormonal production. Due to this response system, the knee joint is trainable and capable of being strengthened. Resistance training will build and/or rebuild cartilage and rehabilitate synovial joints.
4) Full ROM Squats benefits...
· Greater performance through enhanced gluteus and hamstring muscular activation.
· Superior health through tissue elasticity.
· Decrease the likelihood of injury through tendon and ligament strength.
· Increased blood flow and scar tissue removal have significant rehabilitation power.
5) Full ROM Squats cons...
· Increased sheer force placed upon the knee joint
· Requires higher levels of flexibility
· Higher mastery level making it difficult to keep form during the movement.
6) Suggested progression to full ROM squat...
It is a good idea to progressively work towards a full ROM squat. Start with an overhead squat; followed by squatting to a bench; then a parallel front squat; a full ROM front squat; then a parallel back squat; then an elevated heel full ROM back squat; and lastly a full ROM back squat. Focus on these progressions and you will be squat your way to perfection.
Although the full ROM has its benefits, do not neglect parallel squats altogether. The parallel squat will allow you to feel more weight, which can help increase your strength. However, make the full ROM squat your main stable.
Sources
1. Athletic Body in Balance
By, Gary Cook
2. American College of Sports Medicine
3. NASM Essentials of Personal Fitness Training (3rd edition)
By, National Academy of Sports Medicine
Editors: Michael A. Clark, Scott C. Lucett and Rodney J. Corn
©2008
4. The Essentials of Strength Training and Conditioning (3rd edition).
By, National Strength and Conditioning Association
Editors: Thomas R. Baechle and Roger W. Earle
©2008, 2000, 1994
pages 416-417
5. Ten Things We've Learned About Squats
By, Charles Poliquin
© 2012