Muscle Elastic/Spring Energy Research?

[Skilzat85X]

Hello good chaps, I've been meaning to do some research on this subject for a while, but I can't find much research about it. This is probably because I'm not sure of the technical term for it.

Anyways, I was just looking to learn more about the "elastic energy" of muscles for certain movements.

It's probably hard to understand what I'm trying to say, so here's an example:

When doing a vertical jump, to achieve maximum power one quickly bends down, and just as quickly shoots back up, right? This makes it easier to do the jump faster, and subsequently higher, blah blah blah.
However, if you bend down, wait 2 seconds, and then jump up, it's harder to do the movement faster, thus the jump is lower, less powerful, more strainful, etc.

So what I'm looking to do research on is why the first method of execution results in more power than the latter, other than it just feeling right. I think I've heard the term "elastic energy" for muscles somewhere, but I'm not entirely sure where.

So if you know what this principle is called, please tell me. And if you have any links/research on it, let me know as well. Or if you just wanna spill your knowledge on it, then go for it! Thanks!

[Munks]

I believe its to do with the "stretch relflex" action of the agonist muscle. Where when you quickly bend down, it stretches the quads and as a reflex the muscle contracts (usually to stop hyperextention), and because you also contract consciously the speed and power of the contraction is increased. Thus when u bend down and stop for 2 seconds, the stretch relfex is not activated.

I'm pretty certain this is what you are looking for, coz I have done labs where its proven that this increases vertical jump height. :good:

[shengoikee]

*BOING*

is this pretty much the same as rapidly rebounding from something like when you're training using plyometrics? hmm

[Skilzat85X]

*BOING*

is this pretty much the same as rapidly rebounding from something like when you're training using plyometrics? hmm
Yea basically. This increases the power and decreases the conscious exertion of most tricks when I try it. Plus it just feeels good.
I believe its to do with the "stretch relflex" action of the agonist muscle. Where when you quickly bend down, it stretches the quads and as a reflex the muscle contracts (usually to stop hyperextention), and because you also contract consciously the speed and power of the contraction is increased. Thus when u bend down and stop for 2 seconds, the stretch relfex is not activated.

I'm pretty certain this is what you are looking for, coz I have done labs where its proven that this increases vertical jump height. :good:
Ahhh yes, I shall look into this! Thanks Munks, you're the man!

[shengoikee]

plyometric exercises are great, just do them all the time.

like when you come across a wall in the street, jump up on the wall, jump off then bounce straight back up onto it.

it's sort of like being in mushroom kingdom when you bounce off goombas.

[chicanerous]

More potential energy => greater force => greater kinetic energy

[Skilzat85X]

Ahh yes of course, so the question is now, where does the potential energy go if you decide not to jump back up immediately after you bend down?

[Munks]

Ahh yes of course, so the question is now, where does the potential energy go if you decide not to jump back up immediately after you bend down?

Thats probably to do with the elastic properties of the muscle when you rapidly rebound.

For example, imagine a ball, if it is soft like clay, and has no elasticity, then the ball will just splat onto the floor, where as if the ball is a bouncy ball made of rubber with alot of elacticity, the ball rebounds and bounces back...

the amount of rebound is determined by how much energy is lost in deforming the ball then reforming the ball back to its original state... therefore the faster the rebound the more bounce....

its a little confusing, and i cant really explain it full off the top of my head... but i think u get the gist... :)

[rock10]

Ahh yes of course, so the question is now, where does the potential energy go if you decide not to jump back up immediately after you bend down?

"potential energy" is such a weird concept. Then again the only physics I've done is at school where everyone just accepts it and moves on and you're not allowed to think "wtf does that actually mean"?


In this case, since the stretch reflex is neural and everything, if you don't jump back up soon enough then your muscles relax and the stretched state no longer exists. When the muscle is allowed to relax, by its neural control, then the "energy" that had it under tension, and that was prevented from 'going anywhere' by the neural maintainance of muscle rigidity, goes into stretching it out back its full length.
????

[chicanerous]

Ahh yes of course, so the question is now, where does the potential energy go if you decide not to jump back up immediately after you bend down?
The body stores it so that you can release it later by invoking your chi. :tongue:

[chicanerous]

A standing vertical jump is only slightly more difficult to analyze than the bench press, because it still involves primarily changes in potential energy. The vertical jump can be broken down into three phases: a preparatory (or down) phase, a propulsive (or up) phase, and a flight phase. The first two phases occur while the jumper is on the ground. Because the height reached by the jumper's center of gravity is determined by what the jumper does on the ground, let's analyze only the two ground phases.

The movements that occur during the vertical jump primarily involves movements about the ankle, knee, hip, and shoulder joints. Some movement occurs around the elbow joints, but it doesn't appear to be as important as the other joints, so let's examine just there four joints. Let's assume jumping action is symmetrical, so the left and right sides move together.

During the preparatory phase, the ankles dorsiflex, the knees flex, the hips flex, and the shoulders hyperextend. During the propulsive phase, the opposite motions occur at each joint: the ankles plantar flex, the knees extend, the hips extend, and the shoulders flex.

During the preparatory phase, the body is lowered, so its potential energy decreases. The segment immediately about the ankle joint is lowered (its motion is downward relative to the ankle joint), so its potential energy relative to the ankle joint decreases. The contraction of the active ankle joint muscle group is eccentric. The ankle joint motion is dorsiflexion, but the muscle contraction is eccentric, so the ankle plantar flexors are the active muscle group. The segment immediately about the knee joint (the thigh) is also lowered relative to the knee joint, so its potential energy relative to the knee joint decreases. The contraction of the active knee joint muscle group is eccentric. The knee extensors are the active muscle group. The segment immediately above the hip joint, so its potential energy relative to the hip joint decreases. The contraction of the active hip joint muscle group is eccentric, and the hip extensors are the active muscle group. The segment distal to the shoulder joint (the arm) is raised (the arm moves upward relative to the shoulder increases. The action of the active shoulder joint muscle group is concentric. Hyperextension occurs at the shoulder joint, so the shoulder extensors are the active muscle group.

During the propulsive phase, the potential and kinetic energy of all the body segments increase. The contraction of the active muscles at each of the joints in concentric. The ankle plantar flexes, so the plantar flexors are active; the knee extends, so the knee extensors are active; the hip extends, so the hip extensors are active. Closer examination of the shoulder joint reveals that the arm initially moves downward relative to the shoulder joint and then moves upward. This slight decrease in potential energy is much small than the segment's large increase in kinetic energy, so positive work is done, and the shoulder flexors contract concentrically.

At the end of the preparatory phase and the beginning of the propulsive phase, the body is accelerated upward rapidly. The joints all experience acceleration at these instances as well. Strength is required in the ankle plantar flexors, knee and hip extensors, and the shoulder flexors to vertical jump well. (Further examination of the flight and landing phases would reveal an impact at landing that would also stress all these muscles except the shoulder flexors.) Strength (and power) training exercises specifc to these muscle groups may be appropriate.

The only extremes in joint ranges of motion observed occur at the shoulder joint. The hyperextension of the shoulder joint that occurs during the preparatory phase may be limited by the shoulder flexors. Flexibility exercises for the shoulder flexors muscles may be appropriate.

"Biomechanics of Sport and Exercise" - Peter Merton McGinnis

Page through this: http://books.google.com/books?id=PrOKEcZXJ58C&pg=PA321&lpg=PA321&dq=jumping+potential+energy+muscle&source=web&ots=djBN9Srb9t&sig=Q7rSpvEMKyxJg4xlmBzOSf8mdVQ&hl=en

Also, check out page 279 for information about the stretch reflex.

[Aiden Bloodaxe]

This may be a little obvious,but it could also be related to speed X strength = power.Oh,I might have stumbled upon something that may help whilst looking to perfect my bent over barbell rows. >> http://stronglifts.com/the-stretch-reflex-to-bounce-or-not-to-bounce/

Edit: Oh shit,everybody else's answeres just PWND! mine:smile:

Edit#2:Nah,it's actually not that helpful xD!!!

[chicanerous]

"potential energy" is such a weird concept. Then again the only physics I've done is at school where everyone just accepts it and moves on and you're not allowed to think "wtf does that actually mean"?
Potential energy is just a mathematical abstraction -- a convenient way to simplify a complex process in order to quantify the equal abstract concept of work.

[shengoikee]

everybody go do plyometrics now

[chicanerous]

This may be a little obvious,but it could also be related to speed X strength = power.Oh,I might have stumbled upon something that may help whilst looking to perfect my bent over barbell rows. >> http://stronglifts.com/the-stretch-reflex-to-bounce-or-not-to-bounce/

Edit: Oh shit,everybody else's answeres just PWND! mine:smile:
This StrongLifts site is starting to piss me off. It's some random dude (http://stronglifts.com/about-mehdi/) from Belgium with next to no qualifications who has basically decided to profit by parroting the advice of Starr, Pendlay, and Rippetoe.

// hijack

[anfeyd]

Skilz, as people have previously mentioned try to research plyometrics in general. Other things you might want to check out are muscle spindle aparatus and golgi tendon organs as well as monosynaptic reflex.

[anfeyd]

This StrongLifts site is starting to piss me off. It's some random dude (http://stronglifts.com/about-mehdi/) from Belgium with next to no qualifications who has basically decided to profit by parroting the advice of Starr, Pendlay, and Rippetoe.

// hijack

Haha i'm stronger than him which is pretty pathetic. Aside from that he shaves well.

[shengoikee]

me too haha (even more pathetic)

[Aiden Bloodaxe]

This StrongLifts site is starting to piss me off. It's some random dude (http://stronglifts.com/about-mehdi/) from Belgium with next to no qualifications who has basically decided to profit by parroting the advice of Starr, Pendlay, and Rippetoe.

// hijack
Yeah,true & he's not that strong considering I can do the same/more than most of his lift "stats".Meh!Considering I'm 2inches smaller in height & about 10lbs lighter in weight.

Edit:
Haha i'm stronger than him which is pretty pathetic. Aside from that he shaves well.
Yes,you beat me to it.He's a fag seeking praise!

Edit#2:Haha! Look at this.
Teh Fag!
1996. After losing arm wresting to my friends, and to a girl, I decide to build strength doing push-ups. The first time I try them I can’t do a single rep.

[Shaedar]

2003. I lose interest in bodybuilding. But I fear losing my physique if I train for strength. I start doing Max-OT: a mix of bodybuilding & strength training.

Is he serious ?
Not to mention it took him years to learn stuff that takes a few months for most of people.

[Aiden Bloodaxe]

I can't believe I considered his site a quarter decent!?:shocked::amazed: