Interesting Study: Elastic tendons can act as muscle power amplifiers or energy-conserving springs during locomotion
on June 24th, 2010 at 3:48 pmI found the following study very interesting. It was sent to me by colleague Cal Dietz I think the first sentence of the abstract sums it up best. I have thought for a long time that one key to improving performance on the field is training the body to act like a spring.
Teaching the muscles and connective tissues to absorb and release force in a spring like manner. This study looks at the tendon spring and it’s effects at buffering forces that are eccentrically absorbed by the muscles.
Enjoy
-Alel
The series-elastic shock absorber: tendons attenuate muscle power during eccentric actions Thomas J. Roberts1,* and Emanuel A. Azizi1
1Brown University
Submitted 10 November 2009 ; revised 24 May 2010 ; accepted in final form
25 May 2010
Elastic tendons can act as muscle power amplifiers or energy-conserving springs during locomotion. We used an in situ muscle-tendon preparation to examine the mechanical function of tendons during lengthening contractions, when muscles absorb energy. Force, length and power were measured in the lateral gastrocnemius muscle of wild turkeys. Sonomicrometry was used to measure muscle fascicle length independently from muscle-tendon unit (MTU) length as measured by a muscle ergometer. A series of ramp stretches of varying velocities was applied to the MTU in fully activated muscles.
Fascicle length changes were decoupled from length changes imposed on the MTU by the ergometor. Under most conditions, muscle fascicles shortened on average while the MTU lengthened. Energy input to the MTU during the fastest lengthenings was -54.4 J kg-1, while estimated work input to the muscle fascicles during this period was only -11.24 J kg-1. This discrepancy indicates that energy was first absorbed by elastic elements, then released to do work on muscle fascicles during the post-lengthening period of the contraction. The temporary storage of energy by elastic elements also resulted in a significant attenuation of power input to the muscle fascicles. At the fastest lengthening rates, peak instantaneous power input to the MTU reached -2,143.9 W kg-1, while peak power input to the fascicles was only -557.6 W kg-1. These results demonstrate that tendons may act as mechanical buffers by limiting peak muscle forces, lengthening rates, and power inputs during energy-absorbing contractions.
tendon; eccentric; muscle; muscle damage
Hello,
So this is what ldiso’s combined with drops/rebounds are supposed to do?
brandon
In a nutshell, yes. They help develop that ability.
Hello,
Anything to those 5 min. holds at once suggested by Jay?
Kelly Baggett seems to think that past 1 min.(per set)is max.
In other words 5 min worth of 1min. holds are better.
Brandon Green
Hello,
Are there any potentiators FOR Ldiso’s such as heavy lifts,rebounds etc. ?
Brandon Green
Hi Brandon,
I agree with Kelly, and so does Jay!!! when he said that there is no difference in results from holding for 5 min straight or doing 30×10 second holds.
As far as potentiators. Not really. I like doing the WGF core and ab stuff first since the goal of each is correcting movement patterns.