Squatting: Helpful or Harmful?

SQUATTING EXERCISES: ARE THEY HELPFUL OR HARMFUL?

INTRODUCTION

There are a variety of different squatting exercises that are given to patients and clients for various reasons.  Reasons may include performance enhancement, functional activities, and rehabilitation. Not all squats are equal.  The following is a brief review on different squats and what they do:

PARALLEL SQUATS: Top of thigh stops parallel to the floor, roughly around 90 degrees knee and hip flexion.

HALF SQUATS: Knee and hips flex to approximately 60 degrees.

FULL SQUATS:  Top of thigh goes below parallel to the ground, past 90 degrees of knee flexion.

OLYMPIC SQUATS: Maximum knee flexion, buttocks is on or close to ankles with feet flat on the floor.

HIGH BAR SQUATS: Bar high on traps, greater load on quads.

LOW BAR SQUATS: Bar low on traps, greater load on glutes and hamstrings.

FRONT SQUATS: Bar rests on anterior deltoid, greater load on quads (more than High bar squats).

ONE LEG SQUATS/SPLIT SQUAT/LUNGE: Squat performed unilaterally.

THE CONTROVERSY

There has been much debate over the use of squats and the potential harm they may impose on the knee joint.  This controversy first ensued with work published in a journal by Klein in 1961.  Klein hypothesized that deep squatting would stretch ligaments and increase instability of the knee. He found that there was increased laxity in the medial collateral (MCL) and lateral collateral ligaments (LCL).  Despite speculative study methods, these results were published in many lay (non scientific) journals and became an accepted standard that squats beyond parallel (or 90 degrees) would be harmful to the knees. 

There is an assumption that knee laxity may predict knee injury.  This further ‘snowballed” into more people removing squatting from their programs.  In fact, this notion became so widely accepted that the US Marine Corp recommended the removal of squatting from their training programs. 

BIOMECHANICS OF THE KNEE DURING SQUATTING

There are 3 movements that are required for flexion and extension of the knee.

SLIDING (OR GLIDING) – single point on one surface contacting multiple points on another (such as going down a slide at the park)

ROLLING – multiple points on one surface contact multiple points on another (such as a ball rolling down a hill)

SPINNING – single point on one surface rotates on a single point on another (as a top spinning on a table)

DURING MOVEMENT ABOUT THE KNEE, THERE ARE VARYING DEGREES OF ALL 3 AFORMENTIONED MOVEMENTS.  THE SUMMATION OF THOSE MOVEMENTS LEAD TO FORCE AT THE CONTACT POINTS OF THE KNEE.  THESE FORCES INCLUDE SHEAR (ANTERIOR AND POSTERIOR OR FORWARD AND BACKWARD FORCE) AND COMPRESSION (UP AND DOWN FORCE).

SHEAR AND COMPRESSION FORCES

-It has been found that SHEAR and COMPRESSION INCREASES with:

            -DEPTH OF SQUAT

            -INCREASED SPEED OF DECENT

            -FATIGUE

            -LOAD

-it was noted that experienced lifters were able to REDUCE shear and compression forces during lifts.   

ARTHRITIS AND CHONDROMALACIA PATELLA

It is a common thought that overuse of knee joints leads to arthritis and chondromalacia patella (knee cap pain)  However, the following has been found:

-THERE IS A LOW INCIDENCE OF KNEE OSTEOARTHIRITS IN THOSE WHO LOAD THE KNEE THROUGH FULL RANGE OF MOTION

-THERE WAS FOUND TO BE LESS SYMPTOMATIC KNEE OSTEOARTHRITIS ARTHRITIS IN RETIRED WEIGHT LIFTERS

-THERE WAS NO DIFFERENCE IN DEGENERATIVE CHANGES (ARTHRITIS) IN THE KNEES OF WEIGHTLIFTERS VS. CONTROLS (NON WEIGHTLIFTERS)

-NO CHONDROMALACIA PATELLA FOUND IN WEIGHTLIFTERS STUDIED.

THE GREATEST CONCERN WAS THE QUADRICEPS TENDON (LIGAMENT) WHICH HAS BEEN PRVEN TO BE SUCEPTABLE TO OVERUSE INJURIES

            -TOO MUCH LOAD, TOO FAST = PATELLAR TENDINITIS/OPATHY

TAKE HOME MESSAGE

-QUESTION EVERYTHING YOU READ AND ENSURE THEY ARE RELIABLE SOURCES   ALWAYS ASK FOR EVIDENCE AND READ RESEARCH METHODS TO SEE IF THEY ARE VALID AND RELIABLE SOURCES.  REMEMBER, THAT MANY TEXTBOOKS ARE MANY YEARS BEHIND IN PUBLISHING ‘UP TO DATE’ MATERIAL.

-SQUATS ARE A LOW RISK EXERCISES AND DO NOT LEAD TO INSTABILITY AND DEGENERATIVE CHANGES IN THE KNEE. 

-SQUATS CAN BE SAFELY USED TO PREVENT INJURY, IMPROVE ATHLETIC PERFORMANCE, AND CAN SAFELY BE USED AS A REHABILITATION TOOL IF INSTRUCTED PROPERLY.

-BE SURE NOT TO LOAD A SQUAT TOO FAST AS IT CAN LEAD TO PATELLAR TENDON PROBLEMS.