Rate of Force Development

[miaou]

Maiou,

Granted the punching example has been overdone, I just wanted to take a movement and break it down and see what ways one would implement ROFD.

I only used a basketball example when someone referred to basketball, but I actually said I'd like to become a baseball trainer.

Dafree clinic, how it punching with weights detrimental?

If you are referring to punching with 10 lb dumbbells than maybe yes. But what about 16 oz gloves, etc.

I believe punching speed is the exact opposite that lifting weights, in respect to RFD. I mean, when lifting you have a great amount of resistance you need to start applying force on, when punching you have almost zero resistance. So it's not a matter of developing as much force as possible in a small amount of time, it is about developing a given (and very small) force in as less time as possible. So you obviously won't go about it the same way, meaning you are not going to repeat the same movement with less resistance, as that (even if it were possible) would do nothing for you! The general idea is that when you are trying to develop more force in the same amount of time (weight lifting) you lower the resistance and try to do it faster, now that you are developing little force in less time you will add resistance and try to do it as fast.

I remember reading about different ways to train punching power, maybe it was in "Science and Practice of Strength Training". The author was examining ways to simulate the same movement but with added resistance. He began by saying something like: "the obvious example would be punching while holding weight, but then the weight would not be acting against the direction of movement. Then the second idea would be lying on a bench and punching while holding weight; that would be better in terms of punching power since the resistance is applied against the direction of movement, but it is still less that ideal since it would take the lower body completely out of the equation...".

My thoughts on this is simple: bands and (if possible) cables.

Bands have the disadvantage that they offer accommodating resistance, which is dissimilar to the actual punching motor pattern. On the upside, that will add safety to the training movement, as it will take a lot of impact from any hyper-extension. Or alternatively, you will be able to hyper-extend at full-speed without worrying about injuring yourself; training without "holding yourself back" at the end of ROM is very favorable for your speed, that is why when training dynamic effort, it is much better to actually throw the weight, instead of stopping it at the end of the movement.

Cables, on the other hand, offer steady resistance (which will also be affected by acceleration in a similar way to normal punching, unlike resistance bands). They can also be used in "semi-throwing" fashion. The downside is they can be hard to find, the particular machine may not be height-adjustable, being used a lot might result in damage to the machine, or (depending on the particular machine) some pulleys may malfunction at high speed.

I have never used cables but I have used bands in the past. I recommend getting two minibands and using them in two different ways: use one by holding it in your two hands and looping it around your back (so it comes under your armpits and on the inside of your elbows). That will only work your upper-body. The second one, cut it (so it is a straight band, not a loop), fix it to a stable spot at chin height. That will allow you to use your entire body to generate power (make sure the floor is not slippery!).

I hope this helps, or at least gives you an idea of something to try!
edit: I've already taken for granted work on technique and work on power production (power cleans, sprints, etc.)



EDIT: I've also seen the "overspeed principle" being thrown around. Someone devised a way to use bands to assist his punches while he was hitting the punching bag. There are a number of reasons why I don't agree with that (granted I have never tried it myself).

 

[miaou]

Miaou,

I still do not understand how you are so convinced that speed work will not help with powerlifting.

To my knowledge there are no scientific studies that contradict the use of speed work in powerlifting, but there have been experiments conducted at Westside and at Ball State University that tentatively support the use of bands, chains, and DE work. I don't really have time to dig through every Westside article but they are out there. An article posted earlier in this thread notes that lifting heavy weights will increase RFD -- so if RFD has no bearing to heavy lifting why would the body perform a useless adaptation?

There is also considerable history behind the use of speed work in powerlifting, dating back to the 80's. Frequently, top powerlifters incorporate speed work into their training and I find it very difficult to believe that this is just a coincidence or that "it helps them avoid accommodation" (the latter of which can be accomplished with any number of other methods). I have been to a number of dedicated powerlifting gyms and ALL of them performed some kind of speed work. Even IPF lifters!

I also wonder whether you have even tried to incorporate speed work into your training. And if you have, did you use it correctly? Were you strong enough to benefit from it?

Honestly I think this forum is stuck with old-timey training methods, probably because of the large amount of beginners here.

PCP, I have nothing against you having a different opinion nor do I consider myself infallible in any way. I feel that in my answers to your previous posts I explained my opinion fairly thoroughly and I don't feel I have something specific to add to that without repeating myself. Feel free to disagree, and by all means keep doing what best works for you. I hope you can find some piece of information I provided helpful.

 

[chia]

Miaou,

I still do not understand how you are so convinced that speed work will not help with powerlifting.

No one has said that speed work or submaximal work is useless, just that RFD is a fairly unimportant concept in powerlifting.

To my knowledge there are no scientific studies that contradict the use of speed work in powerlifting, but there have been experiments conducted at Westside and at Ball State University that tentatively support the use of bands, chains, and DE work. I don't really have time to dig through every Westside article but they are out there.

Again, submaximal work is definitely useful for increasing max strength. Just because bands or chains are used or because one attempts to move a load as quickly as possible, it is not necessarily true "dynamic effort" lifting. Rather, it is one or another variation of submaximal training which naturally has been around since strength training existed.

An article posted earlier in this thread notes that lifting heavy weights will increase RFD -- so if RFD has no bearing to heavy lifting why would the body perform a useless adaptation?

It's not a useless adaption, it's just useless in the context of powerlifting. Based on your posts you seem to have no grasp of the concept of RFD. You should read the Science and Practice of Strength Training where Zatsiorsky outlines these basic concepts. Just because certain articles use the buzzword "RFD" doesn't mean they have used it correctly. Again, submaximal work, even when performed in a fast manner, does not necessarily train RFD. Improvements in max strength obtained from submaximal work are not necessarily because of improvements in RFD. When the length of the effort is longer than a few hundred milliseconds, the RFD is largely irrelevant. Please try to understand basic concepts before you argue about them.

There is also considerable history behind the use of speed work in powerlifting, dating back to the 80's. Frequently, top powerlifters incorporate speed work into their training and I find it very difficult to believe that this is just a coincidence or that "it helps them avoid accommodation" (the latter of which can be accomplished with any number of other methods). I have been to a number of dedicated powerlifting gyms and ALL of them performed some kind of speed work. Even IPF lifters!

Again, submaximal training has existed since the beginning of strength training. No one has said it doesn't work. Just because a day is labeled as "dynamic effort" does not mean it is true speed training in the academic definition. Rather it is a just one of infinite ways to incorporate submaximal lifting into a training program, which no one has ever argued to be ineffective.

I also wonder whether you have even tried to incorporate speed work into your training. And if you have, did you use it correctly? Were you strong enough to benefit from it?

Honestly I think this forum is stuck with old-timey training methods, probably because of the large amount of beginners here.

Yes, you seem like quite an advanced lifter and you probably would not fit in here. This place is full of beginners--I doubt anyone here could even barely hitch a 2x bodyweight deadlift much less pull it for a triple. However there are a couple of good forums that I would recommend since you're more advanced, including Wanna Be Big and Bodybuilding Dungeon. You really should check them out.

 

[PCP]

Chia,

I simply disagree with some of the training ideology here and wanted to voice my thoughts.

There is no need to turn this discussion into a namecalling contest. It's a waste of everyone's time. Can we not have a civil discussion on this forum?

Look, I am not even interested in posting here if I am just going to get flamed for my opinions.

 

[chia]

Chia,

I simply disagree with some of the training ideology here and wanted to voice my thoughts.

There is no need to turn this discussion into a namecalling contest. It's a waste of everyone's time. Can we not have a civil discussion on this forum?

Look, I am not even interested in posting here if I am just going to get flamed for my opinions.

There has been absolutely no namecalling or flaming--I'm not sure where you see this. I apologize if I've offended you somehow.

Unfortunately concepts such as Rate of Force Development are not matters of opinion and are often misunderstood or used incorrectly. I (and miaou) have simply been trying to clarify these concepts. It's difficult to have a civil discussion if one side does not even grasp the fundamentals. Again, these concepts are outline concisely and clearly in Zatsirosky's work if you would like to learn more.

As much as I'd like you to stay, I have no problem if you're not interested in posting here.

 

[Tosa]

Personally I'm not entirely convinced either way about whether DE is beneficial in powerlifting. Unfortunately, I couldn't seem to find any studies that supported either position with what I would consider solid evidence. However in the studies I read, RFD was either strongly correlated with, or primarily caused by increases in maximal strength (The more time the movement takes, the stronger the correlation or causation). So that's really nothing new, and may not be applicable to someone who's significantly stronger than the particpants in the studies.

My take on DE or RFD in relation to powerlifting is there's isn't anything that disproves it's effectiveness, or the importance of RFD in maximal lifts. But there isn't anything that strongly supports it either, except for the personal experiences of a large number of lifters. And, as has already been stated, there's alternative explanations for why this might be the case, and it could have nothing to do with RFD. But I don't need a training practice to be supported by numerous studies before I experiment with it in my own training. So long as the rationale is reasonable and consistent with what I know (and I think it is, although that's different than believing it to be true) I'll experiment with it, and see if it works for me. As to why it works, I think that's relatively hard to determine, since RFD and maximal strength are strongly correlated with eachother.

 

[chia]

Tosa, it sounds like you're confusing RFD with power when they are two very different things. RFD represents the time constraint of force exertion. Even untrained individuals reach peak force in under one second so unless your sport requires an action on the order of 10's or 100's of milliseconds, it is not usually an important quality. Power, on the other hand, is almost ALWAYS an important quality.

Personally I'm not entirely convinced either way about whether DE is beneficial in powerlifting. Unfortunately, I couldn't seem to find any studies that supported either position with what I would consider solid evidence. However in the studies I read, RFD was either strongly correlated with, or primarily caused by increases in maximal strength (The more time the movement takes, the stronger the correlation or causation). So that's really nothing new, and may not be applicable to someone who's significantly stronger than the particpants in the studies.

No, it's the reverse. The more time the movement takes, the less important is RFD. RFD represents the limitation of exerted force over time. Exerted force is more strongly correlated with maximal strength, the longer the movement.

My take on DE or RFD in relation to powerlifting is there's isn't anything that disproves it's effectiveness, or the importance of RFD in maximal lifts. But there isn't anything that strongly supports it either, except for the personal experiences of a large number of lifters. And, as has already been stated, there's alternative explanations for why this might be the case, and it could have nothing to do with RFD. But I don't need a training practice to be supported by numerous studies before I experiment with it in my own training. So long as the rationale is reasonable and consistent with what I know (and I think it is, although that's different than believing it to be true) I'll experiment with it, and see if it works for me. As to why it works, I think that's relatively hard to determine, since RFD and maximal strength are strongly correlated with eachother.

DE training (in the Westside sense) is not necessarily (and probably not) reflective of improvements in RFD.

DE training (in the Westside sense) is also usually not optimized to generate peak power (typically 30% of 1RM).

Finally, you cannot really think in terms of correlation between RFD and maximal strength since they are quite different things. Think of RFD as the time derivate of force exertion, while maximal strength is simple the peak value of the force-time curve. Understanding exerted force, RFD, maximal strength, etc. in a basic context isn't really a matter of reading studies but knowing the definitions and concepts. Again Zatsiorsky does a very good job explaining this in Science and Practice of Strength Training.

Hopefully this image will clarify some things. In particular, pay attention to the time scale and to the different shapes of the force-time curves:

 

[Tosa]

Tosa, it sounds like you're confusing RFD with power when they are two very different things. RFD represents the time constraint of force exertion. Even untrained individuals reach peak force in under one second so unless your sport requires an action on the order of 10's or 100's of milliseconds, it is not usually an important quality. Power, on the other hand, is almost ALWAYS an important quality.

Even if a motion isn't completed by the time the peak force output is reached, doesn't mean RFD isn't important. Although I'd agree that power is a much more important quality.

No, it's the reverse. The more time the movement takes, the less important is RFD. RFD represents the limitation of exerted force over time. Exerted force is more strongly correlated with maximal strength, the longer the movement.

From "Influence of maximal muscle strength and intrinsic muscle contractile properties on contractile rate of force development" by Lars L. Andersen

 

[Cuban Moses]

This atricle indicates peak power occurs at 30- 50 % max force

Strength Development - It's So Simple Part I



Strength Development: It's So Simple
By Steven Scott Plisk

When looking for the best way to strength-train athletes go back to your high school physics class and recall

Power = force x velocity

A critical velocity or power output is required to execute any skill. Depending on the movement, power production usually peaks at 30-50% of maximum force or velocity. (Figure 1)

Impulse = force x time

In order to executive athletic movements, the object must be rapidly moved through an acceleration path with peak force applied for a very short time (typically about 0.1-0.2 second, whereas absolute max force development requires 0.6-0.8 second. (Figure 2) Brief explosive force production is what separates the good athletes from the not-so-good ones.

Force = mass x acceleration

Once the weight is determined, maximal force (relative to one

 

[Cuban Moses]

Interesting thread I found.

Powerlifting Heads-Up

This could give a bit of insight on why potetionally the westside method works.

"Louie Simmons has stated that you can produce as much force with a 400 pound weight lifted explosively as you can with a 700 pound weight that is your max. Doc has also stated as much. So if we look at the F=mxa equation, if you are lifting a lighter mass but accelerating it as much as possible, is it not possible to produce as much force with 55% of max as you can with say 85% of max? Obviously you can accelerate that lighter mass much more than you can that heavier mass correct?"

 

[ASEGSEA]

PCP, could provide your credentials or experience in physical training? I like what both sides have to say. I do know that when EZA finally provided his experience what he had to say suddenly had different meaning.

I don't mean this in a "prove yourself bitch" sort of way. What I am saying is that if you are a man/woman with much experience and the right creds, and you truly do believe some trainee's here on the forums are stuck in an old-timey routine, then I certainly would like to know how to fully maximize my workout and see the best gains.

 

[miaou]

Even if a motion isn't completed by the time the peak force output is reached, doesn't mean RFD isn't important. Although I'd agree that power is a much more important quality.

From "Influence of maximal muscle strength and intrinsic muscle contractile properties on contractile rate of force development" by Lars L. Andersen

 

[chia]

My impression from reading the abstract is that you understood the results but misunderstood the implications. You noted correctly that "So the correlation between RFD and maximal strength is stronger the longer the movement takes." That is true, and it is also what is to be expected. RFD is a value that depending on two things: the acceleration of speed of shortening and the force produced by muscle (max strength). When the time-frame is short the deciding factor is acceleration of muscle shortening, when the time-frame is long the deciding factor is max strength. That is what the study says and that supports the case that in that the more time the movement makes the more important max strength is and the less important the acceleration of speed of shortening is.
[/I]

These are my thoughts too, but you are a much better explainer than I am. A higher correlation between maximum force and RFD means that RFD is playing a smaller and smaller role as length of contraction increases.

The abstract of that study is not very clearly written. It took me a while to really understand the nature of the study (still not 100% sure on the methods used).

 

[miaou]

I guess a good example to explain that it the following:

In deadlift the bar starts from a dead stop. The lifter fixes his grip, gets into proper position and starts pulling.

A certain amount of time (measured in milliseconds) elapses from the moment the lifter starts applying force to the bar (onset of muscle contraction) until the moment the bar starts moving upwards. By the time the bar starts moving, the lifter is already applying near-maximal force. How long it took for the lifter's muscles to reach that level of force production doesn't matter and will not affect how fast the bar moves. The speed of the bar will only be affected by the maximum strength the lifter can apply to the bar.

If the lifter were to lift sub-maximal weights, then the RFD would play a more important part in how fast the bar is moving, because when the bar starts to move the lifter is not applying near-maximal force to it so the speed of muscle contraction is still accelerating (he still has potential to increase the speed of the bar).

Powerlifting is the sport of lifting maximal weights.

 

[Nosweat]

If anyone has access to 'Fighting Fit' magazine (published by boxing news, but covers various martial arts) there's a good article on this subject as it relates to MMA written by Dan Hardy's strength and conditioning coach. I think it was in the June issue.

 

[Origins]

So miaou and chia, what you are saying is that RFD plays a minimal role in powerlifting because the lifter is already applying near-maximal force when the bar starts moving. However, in sports, RFD plays a much larger role, because you are applying sub-maximal force to the object once it starts moving and therefore still have the ability to accelerate it? That makes sense.

RFD is a product of max strength and the acceleration of speed of contraction...so that explains why training with maximal resistance (ie powerlifting) will improve RFD in a novice. However, once max strength gains slow down in an advanced trainee, that trainee should start "explosive-ballistic" training? What exactly does that mean? Does that imply oly lifting or something else? Obviously this trainee is not training for powerlifting but for a sport in which RFD is important.

 

[Tosa]

I only have access to the study through my universities website, so unfortunately I can't share it. The study was done with 25 healthy, sedentary males. Isometric Knee extenion was used for force measurements. The study produced some graphs, which roughly correspond to the graphs already posted.

While I understand that the maximum amount of force that can be produced is by far the most important factor, I'm not ready to dismiss RFD as a factor in maximal lifts entirely. For example, in the bench press, the force needed to press the bar of the chest, and the force needed to complete the lift (in a reasonable time frame) are different (although how different, I'm not certain). And if my sticking point is 1-2 inches off the chest in the bench press, (and it's typical to have a sticking point near the beginning of the concentric portion of a lift, at least for raw lifters) I want to be producing maximum force at that point, not just near maximum force. It may be a small difference, but I don't think that means it's necessarily insignifcant.

 

[miaou]

I'm pretty convinced that RFD will have minimal-to-zero contribution in competition bench press (paused with near-maximal weights). I really can't come up, and haven't come across, a realistic mechanism for the opposite.

If you are referring to touch-n-go bench press I could try to think a little more about that; see if I actually can come up with a convincing enough reason why/mechanism how RFD would contribute to it.

 

[Tosa]

I was just using bench press as an example, I meant any lift where the "sticking point" is often near the beginning of the concentric portion of the lift, which is most of them.

Also, I'd be interested to see if the graphs involving rate of force production, and time peak force would be different for elite powerlifters. Especially if there was a comparison between those who use DE or other explosive work, and those that don't. However I don't think such a study will ever be done.

Minimal contribution is very different than zero contribution, at least in my mind. It's like tweaking technique, or performing a particular assistance exercise. Individually, each one may contribute minimally, but improve the amount that can be lifted synergistically. And minimal contribution can become significant when someones has achieved a very high level.

That being said, I'm not convinced either way of RFD's importance, and I'm not going to entirely embrace it, or dismiss it. I do, however, enjoy playing devil's advocate.

 

[miaou]

I used the word minimal instead of minor on purpose. I don't think RFD contribution could be
comparable to improvements in technique.

The sticking points often being near the beginning of the concentric doesn't have to do with not developing force fast enough. It has to do with the force-length curves, which are pretty well studied and documented. In in vivo studies you can often come across the force-joint angle relationship instead (which really is closer to practical application). There are plenty of studies on this, if you are interested in searching I guess a good bet would be to include "knee extensors" as a keyword.

The sticking points being often near the beginning of the concentric (in full ROM movements) is not due to insufficient RFD, it is due to a well described mechanism (the insufficient overlapping of filaments in stretched muscle, according to the cross-bridge model), combined with unfavorable mechanics at that angle.


I am trying to think through the RFD contribution in touch-n-go bench press, here is my chain of thoughts...

The lift begins with an eccentric. The speed is slow and the weight is lowered under control. That means that the force produced is obviously less than the concentric, but near-maximal nevertheless. Right before the bar touches the chest the lifter starts exerting maximum force (remember we are referring to touch-n-go), and this is when the force starts becoming from near-maximal to maximal. This is also when SSC comes into play. The SSC has actually been shown to contribute in achieving fast maximal contraction through the stretch reflex (this is also a very well described mechanism). As the concentric begins, the stored elastic energy from the SSC is being released, assisting in the first few moments (as the bar is leaving the chest). The bottom sticking point is typically right now (right after the contribution of the SSC has been played out). The reason for this is described above.

If I try to be real honest about this, I can't say with absolute certainty that there is zero contribution of the RFD, unless I see specific studies outlining the muscle activation during the reversible muscle action. My best thinking leads me to believe that the time between the onset of MVC and the time when the lifter need to have reached maximal force production (in order to break through the sticking point) should be long enough that differences in the RFD would have a minimal-to-zero contribution (minimal, not minor). That is also reinforced by the fact that maximal force production will be reached even faster than in a pure concentric movement, due to the contribution of the SSC.

I could be wrong, but this is my best assessment.