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Categories of Weight Training: Part 12

Continuing from Categories of Weight Training: Part 11, I’m going to forge ahead and get further into the different “types” of power training methods that I outlined in the Force-Velocity curve that I presented last time.  I won’t reproduce the graphic but it presented pure speed training, speed-strength training, power training, strengths-speed training and maximal strength training on the continuum from highest speed/lowest force to highest force/slowest speed.

But before getting into the actual methods and means of training those different ranges, I first need to talk a little bit more about power and the physics of what happens in the weight room a bit; this will lead into the Inevitable Car Analogy.   Hang on for what I’m sure will be a compelling and exciting ride..

The Important of High Power Outputs

When it comes to different types of training, it’s usually assumed that the best way to increase a given capacity is to apply a maximal (or at least optimal) stress.  So in the case of maximal strength (where the primary adaptation is in force output), the focus is on the generation of high muscular forces (typically through moving heavy weights) which is often associated with relatively slow movement speeds.

In the case of endurance type training (where the primary adaptation is an ability to resist fatigue), the focus is on generating some amount of fatigue generally through a focus on duration of the activity (mind you there are different types of endurance and each one has an optimal volume/intensity relationship).  Hypertrophy is a slightly different mix with tension, fatigue, metabolite accumulation and damage all playing interaction roles.

So as you’d expect this means that the primary stimulus for increasing power output is by working in such a way that high power outputs are generated/required by the movements.  I mentioned a few different ways that power might be increased ranging from decreasing the time taken to perform a movement, increasing the weight being moved (the assumption being that going heavier doesn’t make the movement slower) and, although usually impractical, increasing the distance over which the force is generated.

Now, due to the difficulty of changing the distance over which movements are performed (i.e. your legs or arms can only move through a fixed range of motion), usually the focus when we talk about the physics of this is based around changes in the mass of what’s being moved and the time taken to move that mass.  Once again, generally speaking, heavier weights don’t move as quickly and quicker movements require lighter loads and the relationship of change determines the actual power output.

And without going through all of the physics (which I’m not sure I can derive the equations for), what this means is that high power outputs mean reaching high velocities of movement, if only relatively speaking.  Since the idea is to reach those high velocities quickly (since you have limited time/distance over which to move), that means a high rate acceleration.

If this isn’t making sense, think about two identical weight cars (with different engines) accelerating over the same 100 meter track (or over 5 seconds).  With distance or time of movement fixed, the car with the higher acceleration (because it has a higher horsepower engine) will reach a higher ending velocity.  More power will have been both required (by the engine) and generated (by physics) by the higher horsepower car.

So that’s sort of the end-goal for power training, reaching a maximal velocity (via the highest possible acceleration) at the end of the movement such that maximum power output is both required/generated.

Which is really just a very long lead up for me to explain why most traditional weight training movements actually suck for power training applications.

Traditional Weight Room Movements and Power Training

.It dawned me as I started talking about power training methods, within the context of an article series called Categories of Weight Training that I had an immense problem which is this: most power training methods are actually NOT done with traditional weight training exercises.  Quite in fact, as I’m going to try to explain, most traditional weight room movements actually suck for power training.

One exception, and the style of training that has usually been held up for performing power training is Olympic lifting and there’s a reason for that that I’ll come back to.  But fundamentally, the way that the Ol’s are performed makes them distinctly different than the majority of traditional weight room movements (i.e. squat, bench, deadlift type of stuff).

And to understand that I have to try to explain the physics of weight training along with delving deeper into the whole issue with velocity and acceleration.  Yes, we’re going back to 8th grade physics now.  The main thing to keep in mind is that velocity describes the speed of movement (i.e. you’re moving at 10mph) and acceleration is the change in speed that speed (you are accelerating by 1 mile per second per second).   Mind you, there can also be a negative acceleration (or deceleration) and that’s important here so keep it in mind.

The Inevitable Car Example

So say you’re sitting in your car at a dead stop.  It will take some acceleration to get from zero to 30 miles per hour.  But once you’re at 30 mph, if you maintain that speed, your acceleration will be zero (because speed isn’t changing).    If you then want to slow back down to zero, there will have to be a negative acceleration/decceleration.

Now keep in mind what I said above, to generate the most power over any fixed distance of movement means, ideally, accelerating as hard as possible for as long as possible such that the highest terminal velocity is reached at the end of the movement.  So an ideal power training movement starts at some velocity (generally zero) and has you reach the highest velocity possible at the end of the movement.  That will maximize power production.

And this is where we run into problems with traditional weight room exercises, the majority of which have to start AND stop with zero velocity or bad things tend to happen.  So think about a bench press for example: you’re on your back with the bar on your chest. The bar is at zero velocity (even if you bounce it off your ribcage, there is a moment of zero velocity as the direction changes).  You start to press the bar with some force, generating some acceleration and achieving some velocity.

Here’s the problem: unless you want to hyperextend your arms and blow out your elbows, you have to stop at a zero velocity as well.  And this factor holds for essentially all traditional weight training movements save the Olympic lifts.  The starting and ending velocity have to be zero which affects the potential velocity and acceleration curves.

Because to stop at a velocity of zero means that, at some point in most movements, you have to allow the bar to decelerate.  You can do this passively by not pushing as hard or you could do it actively by pulling back against the bar.  No matter what, it becomes impossible to accelerate throughout the entire movement.  This makes it impossible to generate maximum power.

In fact studies show that  with weights even as low as 81% of maximum, over half of the bench press is spent decelerating the bar.  And the problem gets worse as the weights get lighter.  Since the initial acceleration can be higher, the deceleration phase has to be larger and longer as well.  Of course, this is all occurring as the mechanics of the movement are changing with the lockout typically being easier than the midpoint.  So the effect is even more pronounced.

Ok, I’m still not sure this is making sense so I’m falling back on something that has been part of the strength training world for years.

The Second Inevitable Car Analogy

.To try to explain what I’m failing to explain, I want you to look at the following graphic (why yes, I did draw it myself) which shows different conditions involving a car, a stretch of road, a brick wall, a ramp and, inexplicably, Pacman.

In the first three, I’ve shown a car sitting on a piece of road with a brick wall at the end.  In the fourth, there is a jump ramp at the end.  In the third, there is a parachute (looking oddly like Pac Man and yes that is a Super Pac Man powerpill on the track) attached to the car.  And I’ve shown effectively 4 different situations that can occur.  On the far right is my attempt to show what happens with velocity and acceleration in each condition.  Ok, first the graphic with details below.

The Inevitable Car Analogy

The first example is a situation where the car starts to accelerate (note how A goes up as does V) but to avoid running into the wall (the end velocity is zero) has to start decelerating about halfway through.  You can see how acceleration starts to decrease, crossing zero, until a negative acceleration (deceleration) occurs so that the car stops at zero right before the wall.  This represents the majority of traditional weight training movements where starting and ending velocity are both zero and any acceleration at the beginning must be compensated for by a deceleration later on (with larger initial accelerations requiring larger decelerations).

NOTE: I have a strong feeling that the way I’ve presented the acceleration curve in example one is wrong but physics is way too far back for me to be sure (I imagine some physics nerd will correct it in the comments and that’s fine).  The main thing to understand from this example is this: any movement that starts and stops from a zero velocity (i.e. most traditional weight room movements) has to have both an acceleration and deceleration phase; you physically cannot accelerate throughout the entire movement.  That’s the primary take-home point.

The second example is one where the driver doesn’t give a damn and just accelerates straight through, crashing into the wall.  You can see that both acceleration and velocity increase until the end when both drop rather abruptly to zero.  This is what would happen if you tried to accelerate a traditional weight room movement without slowing.  In the weight room, instead of hitting a wall to stop the movement you’re hitting lockout, likely hyperextending your joints in the process.

You could presumably set up in a power rack or something with pins set at the top position and jam the bar into the pins.  But it’s a pretty abrupt stop, great way to blow up your joints although it would make tons of awesome noise.  Anyone who has done martial arts knows that punching into a Makiwara or punching bag sort of accomplishes this: it allows you to punch through the target without pulling your punch but the bag/target acts as a brake so you don’t destroy your joints.  Martial artists are actually taught to aim for a spot a few inches behind the target so that they punch through it.

The third example is the Pacman/Parachute.  Imagine a situation where something is attached to the car which act to increase the resistance that you’re applying force against as you get further into the movement or that otherwise actively decelerates you (like an actual parachute) without you having to change the acceleration you’re applying.  If you could set up a situation where this device brought you to a zero velocity  before hitting lock out/the wall, you could presumably accelerate the entire way through.

In practice this won’t ever happen (which I didn’t really show well in the acceleration curve), there will always be some deceleration at the end but the curve will be flattened compared to example one.  This is at least part of what chains and bands are meant to accomplish (it’s not the only thing of course),  By increasing the force requirements later in the movement (where mechanics tend to give you an advantage anyhow) you can accelerate through more of the movement.  But you still can’t accelerate from start to finish, there will be some end-range deceleration in practice so it’s still not ideal for power production.

And that brings us to example 4, our sweet jump.  In this situation, because the car can be launched (ballistically) into the air, the driver is able to accelerate the entire time, reaching the highest velocity and generating the highest power outputs.    But the physics of the situation, launching the car avoids the need to decelerate actively (example 1), a drastic physical deceleration (example 2) or having to attach something to the car to slow it down (example 3).

You can accelerate, accelerate, accelerate until you go zooming off the ramp.  Now, in the car example, clearly there is a landing issue but don’t focus on that so much, This is just an attempt to explain the physics of this and which situation allows maximal velocity, acceleration and hence power output to be achieved.

What is the Point of All of This?

.Because in an ideal situation, power training would be done with movements that either allow the implement to be accelerated throughout the movement which tends to not be true of most traditional weight training movements (without some modification).

And stunningly, since this is about the right length, I’m going to stop here, having said nothing beyond a bunch of boring physics to set up for the final part of the series.  In it I’ll discuss some ways people have attempted (beyond bands and chains) to make traditional weight room movements better for power training and talk about more typical methods of training the different types of power along with loading, sequencing,  etc.

Read Categories of Weight Training Part 13

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6 thoughts on “Categories of Weight Training: Part 12

  1. Physics Man to the rescue!

    The A curve should be a square wave, going from positive to negative at the half-way point. A constant acceleration produces a linear change in velocity.

    Cheers, Nige

  2. Looking for your thoughts on the Olympic lifts (that’s what I do).

    I’m wondering if the problem you explain is why bands and chains are so popular in powerlifting. Because, in effect, the weight increases as you reach the top of the lift, forcing you to continue driving hard to the finish. It seems as though this would minimize the problem you’ve discussed.

    Thanks for the great articles.

  3. Thank you, Nigel. I knew I was screwing this up but didn’t have the time nor energy to figure it out. Btw, Nigel’s blog is great. Go read it.

  4. Not sure what you’re asking in terms of the Ol’s.

    So far as bands and chains. Certainly part of why they are used are for what I focused on in this article: they flatten the acceleration curve and allow for *more* acceleration over a greater distance because they are changing the resistance.

    Part of it is to provide a more balanced resistance curve. With most movements, things go from easier (bottom) to hardest (sticking point) to easier (as the levers lockout). So consider a heavy squat, the bottom isn’t so bad, you hit the sticking point (where the lever arm is longest and the amount of force required is highest) which is where you usually fail if you’re going to and just about anything you get through the sticking point you can lockout because of how the levers are changing. This means that all movements are limited by what you can get through the sticking point and are often underloaded at the bottom (below the sticking point) and top (above the sticking point). That is, with a fixed resistance.

    Old Nautilus machines tried to provide accomodating resistance with the cam but you’re limited to machines.

    Bands and chains overload the top portion of the movement, where changing mechanics (i.e. arms straightening on bench, legs straightening on squat/DL) tend to make it easier. So it smooths the resistance curve out in a way that better matches most movements. Lighter at bottom and through the sticking point and heaviest where changing mechanics is requiring the least force from you.

    Perhaps the bigger issue is due to the way gear works. Bench shirts and squat suits tend to allow the lifter to move a LOT more weight out of the bottom position than they otherwise could and geared PL’ing is a lockout contest. The gears lets you get way more weight through the sticking point and then you have to lock out it. That necessitates overloading that top position (i.e. board presses, partial squats) and chain/bands let you do it in the competition movement.

    So a guy who would normally only bench 315 off the chest (i.e. he can only get that through the sticking point) only needs to be able to lockout 315. But if his shirt lets him spring 450 off his chest, he has to be able to lockout 450. So he has to train the lockout position with that much more resistance. And unless he trains with the shirt, by definition he can’t get that started off the chest to train it. So he starts with a weight he can start and lets bands chain overload the top. It’s just competition specific to geared PL’ing.

    Does that clear it up?

  5. For the third example that should really be a graph of (power output by the engine)/mass as the acceleration is really the same as in the first graph, but I get what you mean.

  6. Yeah, hence ‘kind of’ in the notes. It’s really just more of a flattened version of Example 1 for Example 3.

    Hopefully the descriptions made it clear more of what was going on in the different examples. Thanks for the catch, though.

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