Sunday, February 11, 2007

Biomechanical efficiency and force production


There seems to be some confusion over the difference between efficiency of a movement, biomechanically, and efficiency of effort, from a force production standpoint. Some are confusing using maximum force production in a movement and ‘inefficiency’ of technique. This is wrong. Saying that there is just one optimal way to lift something is almost true; each person will have their own individual, optimal mechanics to lift an object, dependent on their limb lengths, tendon insertions, muscle fiber type,etc. Each person will have their optimal position but that will differ from person to person. Within that ideal, individualized unique form there is also the issue of how much force one uses to complete the lift.

‘Dr Squat’, Fred Hatfield, used the term compensatory acceleration( CAT) to describe applying maximum force throughout the entire range to create more overload. Hatfield determined that by applying max force throughout the entire range of motion he could create more overload in one set of five reps that he normally got from 5 sets of 5!

And let’s not forget, no overload, no adaptation. The S.A.I.D principle implies overload. Of course overload for an endurance contest is NOT the same as overload for a strength contest. Louie Simmons took it a step further by attaching chains and or bands to the bars to deal with the inevitable de acceleration that takes place at the top a barbell movements ROM. With band or chains one can push all the way to the top of the movement and not have to slow the force production down.

Of course this is an advanced technique and one needs to know when and where to apply max force and still remain ‘in control’ as well as use ideal biomechanics. One does not preclude the other. Using compensatory acceleration is NOT the indiscriminate throwing of the weight around or being inefficient That is simply not what the technique is about. And using CAT is NOT being inefficient biomechanically, it is maximizing the biomechanics to learn how to produce the most force throughout the entire range of motion. Hatfield said the loads best suited for CAT training are 70-80% as once the loads go above 80% you will have to push maximally anyway to get the bar to move fast enough to make the lift(s). This was before chains and bands, and Louie uses less bar weight and more bands and chains to accommodate the resistance.

As far as kettlebells go lets look at the swing as an example. Think of the difference between swinging a bell for 100 continuous reps and doing 100 reps in 10 sets of 10. If you do 10 sets of 10 you can use a much heavier bell, swing the bell higher and harder on each rep as well as pulling the weight down to create more kinetic energy on the downswing producing more force one has to reduce and reverse. More work,more acceleration, more velocity and more force per rep equals more overload and a greater training effect. The result will be more strength, speed and power available for your use. Is that the way to train if your goal is 100 continuous reps? Not all the time as you must develop pace, aerobic capacities and be able to go the distance first. But it WILL make you stronger if one uses the HIIT methods at least some of the time.

You can't use the two pood for reps if you can't snatch it once.You must be strong enough so that the weight is submaximal.

If your goal is to squat or deadlift more ,or be stronger or faster in general, than the HIIT method will reap many more dividends than the high rep method. If your goal is strength endurance then doing 100 continuous reps will greatly help that but there is no way one can last for the entire set using the same force production you would do for just ten reps. Just can’t do it.

Attach some bands to the kb and do your swings as high as you can. This will give you a great feel for what max force production requires on the ascent as well as the descent. The good thing about the kb is that you don’t need the bands, just a heavier kb and a continued rooting to create as much force as possible on each rep. Keeping swinging higher each rep and if it is too easier there is always the Beast. If that is too easy do it one hand or attach some heavy bands. My guess is that it wont be too easy for almost anyone. Pavel wrote a great blog on the subject here: http://www.dragondoor.com/kettlebells/news/archives/2006/09/compensatory_ac.html


I like using the swing as an example as the snatch is more of a competition skill rather than a training exercise. Increasing your force output and rate of force production in the swing will help your snatch when you go back to your comp form just as using the box squat will help your free squat when you go back to that form. There is also the issue of training exercises and techniques, in which one is trying to create an adaptive response via overload, and competition form, where one is trying to create the most efficient movement possible.

Lets looks at the squat as an example. In training one can use the box squat to increase the overload. The box squat makes the squat HARDER by breaking up the eccentric/concentric chain and allowing one to sit back further than would be possible without the box. Is the box squat less efficient than the stretch reflex competiton squat? Yes, but for a purpose. To overload the involved muscles and create more of an adaptation.When one takes out the box and allows the stretch reflex to occur, the squat is easier.


Same with the deadlift. By pulling off boxes one makes the stroke longer, the pull harder and the overload greater. When one goes back to pulling off the floor it seems the bar is at your waist and the pull very short! Does this mean one should use the same exact technique off the block as you do off the floor? Close but no. Louie advocates those pulling sumo NOT to use that form too regularly in training for overload as it is TOO EFFICIENT with little strength gains in the appropriate muscles. Of course this is just one approach but I have not seen the point argued against cogently. Many may not LIKE it but I have not seen the point negated.


If your goal is to do hundred of reps in a movement one absolutely has to train with the form you will use on the platform, but if your goal is more strength, more power, more explosiveness, more speed then training those qualities is a must. But just as a swimmer will do stroke work to maximize efficiency in the water there also must be sprint and speed work to actually gain strength and power. One should not confuse the one with the other. Another interesting article on compensatory acceleration: http://www.strengthcats.com/explosiverepsvariableresistance.htm


Let’s remember, efficient biomechanics and maximum force production are NOT mutually exclusive.

3 comments:

Royce said...

Great posr Rif, let me know when the book is coming out will ya'!
Pavel posted something one time about doing strength days on Mon and Thur. then conditioning on Tue and Fri. He said that the strength days were the days for low rep sets of swings, cleans, and snatches for strength.

So would it be benificial to work on ballistic strength 2 days a week then work on speed on the conditioning days. So you kinda have a RKC style ME/DE setup going.
I realize they would not be true ME/DE days, I am just wondering if they would compliment each other.

Mark Reifkind said...

thanks man, I will let you know but do not hold your breath. I can only write for beans first thing in the am and right now I am at work at 5 am 5 days a week.

You could definitely do ballistic strength work in one workout with a heavier bell( keep the reps low and the explosion level high and then DE day the other day with still low reps with a lighter bell but with short rest periods.
thanks for reading man.

Royce said...

I understand on the early mornings. Monday everything changes for me. school 4 days a week 8-10 hours a day. Then later this year 18 months straight of 8-15 hours days of either school or clinicals. Then after I pass my boards 4-5 days a week of 12 hour nights.
I am going to work a crapload, because first of all, it's my nature to work a lot when I can, and second to give Barb a long long break from her hellish work schedule, she needs it.
Even if I had something to write about I couldn't do it!!!

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