Tuesday, February 15, 2011

Front Squat versus Back Squat

In a recent post, I explained why and how alot of folks have lower back pain. Here I just want to quickly compare two common exercises, the back squat and the front squat. Personally, I reccomend the front squat for the general population, and progressing on to the split squat once proficiency is gained. Having worked with both athletes and the lay population I hve noticed that the vast majority of trainees end up creating a higher torque on the lower back structure whilst performing the back squat in comparison to performing the front squat. Allow me to ellaborate on this a little more.

So for those who have not taken physics or are just a bit rusty, torque is essentially force x moment arm. The moment arm is the distance away from the point of rotation and always happens to be perpendicular to the vertical line of force.

T = F x MA
Torque = Force x Moment arm

Now in the situation I am elaborating on, the point of rotation is at the hips. The muscles of the lower back as well as the hip extensor (ie the gluteus maximus, hamstrings) fight to keep the back in a more upright position but generally do not do as great of a job when the individual is in the back squat. Therefore the trainee has more of a forward lean pushing the moment arm further from our respective point of rotation (at the hips) and creating more toque on the lower back. Below are illustrations that may do a better job of allowing one to see what is occuring.



Fig. 2-31 from Starting Strength by Mark Rippletoe. Calculations in red done by "spiderman" -forum member at startingstrength.com



The calculations above were actually done comparing the low back squat (far right) to the high bar back squat (middle) There is controversy as to which method spare the lower back best. However there is not controversy as to whether the front squat reduces the moment arm. Lets use the hypothetical calculations above for example. The cartton is squatting roughly 225 lbs (100 kg) in the front squat this results in 13.7 Nm of torque on the lower back where as in the best case scenario for backsquat the torque is 15.9 Nm. Therefore the frontsquat reduces torque in this scenario by about 13%. You can also see less forward lean in the front squat when comparing the 2 photos I have posted.

 
Notice how I have adopted a more upright posture here which would "spare" the lower back, particularly during heavier loading


Before pressing forward, I will say that this cartoon does not do everyday life scenarios 100% justice. For instance while the front squat does spare the lower back quite a bit, the more upright posture may cause a more anterior tracking of the knees placing more stress on the patella. With that said, the front squat is great for individuals seeking to spare the lower back while squatting. Most individuals I have worked with have been able to pick up on them fairly easily and as long as the trainee is not a strength athlete, it is also a positive that inferior leverage gained in the front squat forces one to use less weight even further reducing load on the spine.



In the back squat there is more forward lean. Even more would occur in a situation where I used a challenging load.

Alright well I will stop boring everyone on the intricacies of back squat vs. front squat. Last words; The front squat is best for the average Joe or Jane who is not concerned with necessarily using huge weight. The lift is still great for athletes as well, but the back squat is generally used in these populations to facilitate a base of strength.  However if knee pain is experienced then front squat may be the lesser of the 2 choices. Other great lowerbody lifts include the deadlift and split squat. For those who find the barbell too challenging at first start with dumbells or kettlebells (see here). Have a safe and productive workout !


 


                                                 

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