I’m going to take a break from my usual idiocratic writing style on my website; and let you into my scientific, engineering part of my brain for a second.
Today’s topic of choice is perpetual progress and “work”.
“Work” is the most important concept of muscle gaining and strength building. The more “work” your muscle can perform, the bigger and stronger you will become (provided you’re fueling yourself properly). This is also supported by Wolff’s Law and Davis’s Law. The body will add tissue (hypertrophy) along lines of stress (lifting weights) in order to alleviate that stress (make it easier for the body to perform under that stress).
“Work” is also vital when computing “Impulse strength” for explosive athletes, but that is a different set of equations for a different day. “Work” is also related to “energy” (aka calories), but again, different equations, different day.
Let’s look at the physics which allow us to state such an “outlandish” claim that progress can be made everyday. Remember, if you are increasing your muscle’s work capacity, your body is laying down more tissue (or making existing tissue more efficient) to make it easier next time. Increasing work capacity on a daily basis seems like a great way of progressing faster, no?
Work is defined as the amount of force required to move a certain object, a certain distance.
In equation form, it looks like this:
Since most people, don’t have a way of continually and accurately measuring force (or a Tendo), let’s break that down into it’s components (Newton’s 2nd Law): Force = mass x acceleration
Combining those two equations, we see that work is how fast you can accelerate a certain mass over a certain distance. Simply put:
Like force, acceleration is not readily measured within the constraints of a gym session. Let’s make that simpler as well: Acceleration = distance divided by time-squared.
Now let’s relate acceleration to work by combining equations 3 and 4:
The final equation of easily measured metrics is that work is the mass of the object multiplied by a certain distance-squared divided by the amount of time it takes-squared. That’s just a more complicated way of stating this:
Voila! There are our 3 easily measureable metrics that we collect.
“But wait, are you saying that I need to measure my ROM for each movement and the amount of time each rep takes?”
Not at all, it’s much simpler than that. All it takes is a general understanding of what happens to “work” when the different variables change.
Let’s talk about those variables.
Your ROM on each rep is usually a constant distance; however, you can think of distance as the total number of reps you do for a given movement. The more reps you do, the more distance that object has traveled (and vice versa).
Time does not need to be measured on a “per rep” basis. As long as you measure time on a consistent basis, you can either do it “per set” or “per movement”. Again, as long as you’re consistent, it doesn’t matter which method you choose, and in that sense, “per movement” is easiest.
Mass is quite simply the amount of load you use on a given movement.
So, as can be seen in Equation (6), if the mass (amount of weight) increases, and all other variables stay the same, work increases. If the distance is increased (number of reps), work increases. If the amount of time it takes you to perform a given movement *decreases*, work *increases*.
The tricky part is when more than 1 variable changes at a time, which is normally the case. However, if you consistently measure each metric the same way every time and use the same equation every time (which NEVER changes), you can simply input your load, number of reps, and amount of time into Equation (6) and see if your work capacity has increased. This may be an oversimplification for diehard physics nerds, but c’mon, how many of those do you see in the gym? This method is probably valid for 98% of people in the weight room, and those other 2% are people that should probably be using the tendos and power plates.
Getting back to our original argument, that a personal record can be achieved everyday, we argue that any time your work capacity is increased, you have just set a new PR. People get their panties all sorts of bunched up when we claim this. I’m not sure why. If I can do more work this time than I did last time, it is obviously a “personal record”. Why are you limiting yourself to just one metric? Progress is not made in one direction; progress is made in all directions.
Dave Sandel is a Movement biomechanics coach candidate who is available for distance and in studio training in the Minneapolis area. You can learn more about him on his website Athlete Creator
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I think most people concentrate far too much on just adding more weight to bar, and that’s where this whole “you can’t PR every day” thing comes from. Once you start tracking volume and density a whole new world of PR’s open up to you, and they are valid PR’s, and they CAN happen every workout.
If you concentrate on increasing your volume and density you will make much better progress on adding weight to the bar, at least that’s why I have found. I very very rarely do 1RM lifts, except for when getting close to a competition to see where I am at, because I have consistently found the best progress happens with lighter weights for lots of volume in minimal time.
Also I think the best PR’s of all are improvements in quality of movement, which can be harder to quantify, but being able to squat deeper or lift overhead with straight arms instead of them being bent etc are way better than any other kind of PR.
beautiful logic. Me loves the simple logic of algebra.
another note.
Because the distance and time are squared, they have a larger impact than mass alone. A doubling of mass increases work 2 fold. Double distance (number of reps) and the work is multiplied by a factor of 4. Cut the time in half and work increases by a factor of 4 also.
if the goal is to increase the work load of the body, then the cutting rest and doing more reps is the most logical goal. (which is what you have been saying all along)
Gene,
Isn’t that interesting that in several calls & articles we have said that density is one of the most valuable variables to increase?
Strangely that makes me really want to go lift. Who ha Physics!
kris…. i totally agree with you. everybody just wants to ‘up their bench’ press.
sandel I think this is an amazing breakdown, and something GS athletes really understand well. the metrics we track in training are exactly what we have been talking about. add more time, add a few more reps, add volume to the day and you KNOW you have made progress. just jumping bell weight for 1 rep means absolutely nothing. AND, the best athletes I’ve seen and talked too are primarily concerned with movement quality, and I feel like this is a quality that is almost totally ignored.
Elegant and simple way to justify our use of:
-intensity
-volume
-density
as metrics of tracking progress
and how they are interrelated
expressed physic(s)-ally
through the formula for work.
Of course
each variable affects the others
just as each movement affects the others.
Well done, Sandel.
Thanks, everyone. I knew that 5 years of engineering school would pay off eventually.
Wait, what’s that? You learned simple algebra in 7th grade? Dammit.
NICE JOB DAVE VERY WELL WRITTEN
Thanks, Mike!
Let me guess…mechanical engineer (I’ll check your website in a bit)? Great post – it’s always interesting and fun to see the ways different people break down a metric or wrap their brain around what they’re doing.
Christopher,
Mechanical Engineering is for guys that aren’t smart enough to be electrical engineers.
Thanks for the comment!
Dave, awesome piece and very convincing (hopefully to those who still need convincing).
I can’t wait for the companion piece on the concept of “efficiency” in engineering and how ROM testing replicates this for exercise.
Don’t make me cobble it together and fuck it up!
That is coming, right?
Diehard physics nerd checking in.
But seriously, I like what you’ve done here. The only real problem with this concept is the lack of accurate and detailed data points. I could quite easily measure these variables (albeit at some cost) by using an infrared dot on the weight and camera. Simply record distance traveled per rep and the time it took. Mass is known. THis con be done with a nintendo wii remote, as is demonstrated here (example uses infrared dot for 3d video gaming, but it provedes proof of concept):http://www.youtube.com/watch?v=QgKCrGvShZs.
Brad, have you seen the work some of the Kinect hackers are doing?
I was thinking the other day that the application of that tech could be used for a similar purpose, but due to the skeletal and optical tracking nature it could also be used to record rep speed, deviation from original recorded path and even facial expression changes, as well as the obvious sets/reps & time.
Basically, if someone coded up that interface (with a record function to “enter” a movement so that it doesn’t have to know all your moves) it would be the ultimate workout buddy to record your data for whatever a kinect costs.
The raw data from that could surely be easily plugged into equations like Dave’s here to let you know which metrics you progressed in and how much.
Also, the reason I think the Wiimote tracking hack would be unsuitable is due to not having a consistant 2 IR dots facing the Wiimote camera during rotational movements, defeating the limited depth tracking in the technology and disallowing many “custom” movements.
hmm, not so sure about that. The absolute vast majority of work done lifting will be done in the positive Y-direction, that is, away from the center of the earth (not “up,” but that’s the subject of a different rant). Almost all of the “twisting” “custom” moves produce a lot of movement along the X-axis which produces pretty much zero work. I would program the system to record only movement in the positive Y-direction.
For example, in a clean, you must whip the bar forward slightly, but this movement only indirectly contributes to work done. I should also point out the massive weight (no pun intended) that the acceleration of gravity provides in the positive y-direction; any acceleration on this direction is a net acceleration and mus cancel -9.8m/s^2, whereas x-directional movement does not.
I agree and understand your point re: the limited impact of the x and z axes in the workload of a movement. My thought regarding tracking of these lies more in measurement of deviation from original form, whether due to internally guided correction or failure to avoid element of effort.
Also such data could also give feedback on things such as achieving a more intense angle on a back bridge type exercise, etc..
Ok, I wasn’t going to comment on this because it’s kind of behind us already, but I thought of something to add to my original statement.
Original: You are absolutely correct that it would be easy (for someone) to hack together something like that, using a Wii or camera. Here’s the problem with that: where does the VAST majority of people workout? In a private training facility, or a commercial, globo-gym? How many people are going to go to Gold’s, position their equipment in such a way that they can align a dot and a Wii controller? How useful would that actually be to the regular gym-goer?
We champion biofeedback as an easy-to-use, end user product. This only complicates the process (unless training at a private facility that is already set up for it.) You are also taking the “bio” out of biofeedback, by basically making a homemade Tendo.
Cal Dietz, head strength coach at U of MN, trains some of his athletes in this exact way, using “auto-regulation” based on Tendo results. Can we claim that he is using biofeedback? Probably not. (But Mike T is working on that)
So again, your methods are absolutely correct and would be substantially more accurate, but for what purpose and for whom?
Additional thought: If we’re going to cobble together a homemade Tendo, I would think that using the Nike+iPod accelerometer would be more portable (user-friendly) and even more accurate than a Wii or camera.
Well said Dave!
I meant this as a possible (bonus) addition to our recording of data, not as a replacement for biofeedback, as you seem to imply. Obviously this is not geared toward the average gym-goer (not every product has to appeal to huge population groups.
I’m describing the setup that I myself would make and use. If somehow I can make it coherent enough to sell it, great. To be honest though, I’d rather see everyone come up with their own system.
I like the accelerometer idea, but i wonder whether it has the accuracy to allow the derivation of distance for such small increments – it was designed for running and probably only records steps, not the exact distance of each, then calculates with an average stride length. Of course, i’m only guessing, but it seems like an accelerometer might be a little too inaccurate.
please prove me wrong, because it would save a lot of time and effort.
Pro tip: The Wii controller uses an accelerometer, but you would still need the IR dot using just that.
In other news, in exploring this topic, I have a pretty wicked idea for developing something. Dangit!
Exactly, I bet that if you invested a few days programming, you could have it automatically graph and analye trends in you work capacity – ever-updated, super-accurate, graphically-displayed records of your workout progress for less than $1000
You mean like what all the Movement Minneapolis members have access to?
Word to that
Curious when you may be selling this to others David.
Nice post david.
man some really good points here by everyone. Thats some pretty smart stuff in this article. Good read. Thanks for posting.
@Piers & @Brad
The easiest way to do it would be with Kinect hardware. In fact you don’t even really need Kinect hardware, you can use almost any webcam with OpenCV.
All you do is put a bright reflective spot on the end of the bar, or even on the side of a kettlebell for snatch/lccj/jerks.
I don’t have the time or coding chops to do it, but it’s pretty damn easy.
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