Thursday, March 1, 2012

The Bench Press-Part I

The Bench Press-Part I

***One of the most popular free weight exercises; yet one of the most misunderstood exercises***

 The reason I say misunderstood is that a large percentage of the gym population is performing this exercise in a manner that places them a greater risk for injury than they might realize.

As I stated in my blog posted back on Oct. 16, 2011- What Is Good Exercise Form? (if you haven’t read this blog,  I highly suggested reading it to help put this article perspective), all exercises have a certain amount of risk-to-benefit ratio.  The goal for most of us is to find exercises that have a high benefit/low risk ratio.

Where the bench press is concerned many who have a goal of general health/fitness and the aesthetics; are performing this exercise using the form/technique that was developed by the sport of Power Lifting.  The problem with this is that this form can be very detrimental to the long-term health of the shoulder joint.

The crude version of the Brench Press that eventually evolved into the exercise as we know it today first surfaced in the early 1930’s.
The form that we most frequently see today mirrors the rules for the strength competition we know as “Power Lifting”.   It is very surprising to me that much of the research findings into the biomechanics of weight lifting has not filtered down to the everyday gym floor.  These research findings have been out for several years now, but the “old school ways” seem to be hard to break.  Even more concerning is that a quick google of the words “Bench Press”, will feed us links that give us the standard Power Lifting form.  Also, a glance at many of the mainstream fitness magazines and bodybuilding books will again yield the standard Power Lifting form. 

It is not until you delve into the teachings of such modern day fitness experts such as Douglas Brooks, M.S., and Everett Aaberg that you realize the hidden dangers of the “Power Lift” version of the Bench Press.   Also, it will be a great surprise to many that using this form will limit us from reaching our maximum muscular development potential. 

Now let’s get specific about this exercise.   The main problem with the Power Lift style bench press is that it requires us to lower the bar all the way to the chest (as seen in the photos below).

As can be seen in the photos above, when the bar is lowered to the chest (elbows going below the midline of the body) the larger more powerful pectoral  muscle is stretched  which lessens its ability to generate force.    The greater the stretch, the less force this muscle is able to generate, thus putting the pectoral muscles at mechanical disadvantage.  As a consequence of this a larger portion of the loaded barbell weight is then shifted to the much smaller and more venerable shoulder joint.  Here in lies the danger of this method for the Bench Press Exercise.    The shoulder joint is one of the most complex joints in the body, and thus very susceptible to injury. 

Above is a very simple (layman’s terms) explanation of this issue.  For those who would like a more explicit explanation of the anatomical issues involved, I listed an excerpt below taken from Douglas Brooks’ book Effective Strength Training (Official Textbook For The International Weightlifting Association). 

How “Deep” Should A Chest Press Or Flye Be Performed?
It is common, when performing chest exercises to bring the fists to the level of the chest, or to cue “touch the chest” with, for example, a barbell.  However, this places the joint in a loaded, horizontally extended/abducted position, which in turn puts the shoulder joint capsule at risk for injury. Cahill (1992) was the first to describe a series of weight trainers who suffered trauma to the distal clavicle.  In other words, hyperextension of the shoulder—elbows behind the midline of the body—places excessive stresses on the acromio-clavicular joint during pressing movements, and is likely to contribute to an injury process in this area of the body (Reeves, et al., 1998 Weight Training Injuries, Part 2).

In addition, allowing the elbows to move beyond the body line that divides it into front and back halved decreases the force angle (the line formed from the elbow to shoulder) of the shoulder.  As the force angle decreases, the ability of the pectoralis major to produce muscular force continually decreases.  When the muscle is extremely stretched at this angle, insufficient actin and myosin overlap occurs. (Actin and myosin are the protein filaments that slide past one another to produce muscular force and movement.) Insufficient overlap leaves the muscle in a position where it is not capable of effectively producing muscle force, which in turn leaves the join vulnerable to injury.  Why? The joint is literally being held together passively by relatively weak shoulder muscles and ligaments, since the pectoralis major is largely incapable of producing significant force.  Any exercise that places the elbow behind this mid-body line places the shoulder at a mechanical disadvantage that may contribute to rotator cuff injury or anterior shoulder instability (Reeves et al., 1998 Part 1; Wolfe et al., 1992). The pectoralis major doesn’t have a good line of pull until the elbow-shoulder line reaches a point where it is in line with the frontal plane that divides the body into front and back halves.

In the coming weeks, I will post Part II of this blog.  In Part II,
I will break this exercise down into its most basic components and present a safer more effective way to perform it.

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