Questions related to PPST about intensity & power calculation.

[TalEphrat]

Hi Rip,
I'm currently reading PPST (2nd edition) and two questions came up. I haven't finished all the book, but as I understood up to this moment, my questions are still relevant.

1. At pages 36-37 the volume and intensity are discussed. I accept the volume calculation, but something in the intensity calculation is bothering me.
For example, if my 1RM is 100kg, and I do 3 sets of 5 with 80kg - the volume is 1200, and the intensity is 80%. But if I do 5 sets of 3 with 80kg, or 15 singles with 80kg - both the volume and intensity of that session remains the same. But 15 singles of 80kg are not the same as 3 sets of 5 with the same weight.
I thought about calculating it also relative to the "lift level". The level is "how much will it worth compared to 1RM". For example, the level of 80kg for single is 80kg. The level of 80kg for a double, is 80/0.95 = 84.2kg. For triple - 80/0.9, for 5 - 80/0.86 and so on, according to any calculator you think works best for you (in my experience the Brzycki works best for me).
So 3 sets of 5 with 80kg will be - 80% * (80/0.86)/100 = 74.4%
5 sets of 3 with the same weight will be - 80% * (80/0.9)/100 = 71.1%
15 singles with the same weight will be - 80% * (80/1)/100 = 64%

So yes, the absolute intensity, as you suggest, is correct - because it is the absolute intensity. But my suggestion calculate the intensity in relation to the specific set you did.

What do you think about that? Any chance I came up with a good idea, or am I missing something?

2.
A. At page 45 you present a calculation of power. For the power clean it's:
Work = 150kg X 9.8m/s2 X 1.27m = 1866.9 N m
Power = 1866.9 N m / 0.6 seconds = 3111.5 watts

It may sound stupid and obvious - but these are the watts per second that generated during that power clean, right? (watts per second aren't written there)

B. The relative power output at that case is: 3111.5 watts / 140kg = 22.2 watts/kg
We're still talking about watts per second, right? (per kg)
Because, I'm not so familiar with the cyclists calculations, but they're always measure the cyclist quality by watts per kg. And 6.5 watts/kg counted as Elite level...
So how is it possible that someone with 150kg power clean who weighs 140kg is MUCH "better" than elite cyclists in term of power?
My guess is that they measure it by, for example, how much watts per kg you can generate for an hour, and not for a "single rep". But I really don't know, and it's possible that I said quite much bullshit.



Thank you very much!

[Mark Rippetoe]

Hi Rip,
I'm currently reading PPST (2nd edition) and two questions came up. I haven't finished all the book, but as I understood up to this moment, my questions are still relevant.

1. At pages 36-37 the volume and intensity are discussed. I accept the volume calculation, but something in the intensity calculation is bothering me.
For example, if my 1RM is 100kg, and I do 3 sets of 5 with 80kg - the volume is 1200, and the intensity is 80%. But if I do 5 sets of 3 with 80kg, or 15 singles with 80kg - both the volume and intensity of that session remains the same. But 15 singles of 80kg are not the same as 3 sets of 5 with the same weight.
I thought about calculating it also relative to the "lift level". The level is "how much will it worth compared to 1RM". For example, the level of 80kg for single is 80kg. The level of 80kg for a double, is 80/0.95 = 84.2kg. For triple - 80/0.9, for 5 - 80/0.86 and so on, according to any calculator you think works best for you (in my experience the Brzycki works best for me).
So 3 sets of 5 with 80kg will be - 80% * (80/0.86)/100 = 74.4%
5 sets of 3 with the same weight will be - 80% * (80/0.9)/100 = 71.1%
15 singles with the same weight will be - 80% * (80/1)/100 = 64%

So yes, the absolute intensity, as you suggest, is correct - because it is the absolute intensity. But my suggestion calculate the intensity in relation to the specific set you did.

What do you think about that? Any chance I came up with a good idea, or am I missing something?

You may be on to something here.

2.
A. At page 45 you present a calculation of power. For the power clean it's:
Work = 150kg X 9.8m/s2 X 1.27m = 1866.9 N m
Power = 1866.9 N m / 0.6 seconds = 3111.5 watts

It may sound stupid and obvious - but these are the watts per second that generated during that power clean, right? (watts per second aren't written there)

B. The relative power output at that case is: 3111.5 watts / 140kg = 22.2 watts/kg
We're still talking about watts per second, right? (per kg)
Because, I'm not so familiar with the cyclists calculations, but they're always measure the cyclist quality by watts per kg. And 6.5 watts/kg counted as Elite level...
So how is it possible that someone with 150kg power clean who weighs 140kg is MUCH "better" than elite cyclists in term of power?

The power output is measured over the time it takes to perform the clean. Over that period of time, 0.6 seconds, 3111.5 watts is developed. Since the work is not being performed repetitively, the power is not expressed as watts per second.

[Manimal]

If i remember correctly seconds dont have to be written there because the more basic SI units for watts is (N*m)/s

[Barry Charles]

But if you did 3 sets of 5 reps in 10 minutes, your power would be:

1800x3x5/60= 45 Watts.

Pulsed lasers, which I know something about as opposed to lifting, might be one Joule per pulse, and a pulse might be one nano-second. That's 1giga-watt! But if it only pulses once per second the average power is 1 Watt. So the safety guy says a billion Watts will explode your retina, the tech says relax it's only a one watt laser, and the sales guy quotes which ever number sounds better when he says it.

[Karl Schudt]

I think your formula has a bit of a problem. As I see it, it's this:

Weight/Actual 1 rep max * Brzycki 1 rep max / actual 1 rep max. You are multiplying two percentages. It gives me odd results. Think about it: you do a single at 80% of your 1rm, and the intensity is 64%? Shouldn't the intensity by definition of a single be the same as the weight/1rm? The intensity should diverge from the actual percentage as the reps go up. Add a square root to the whole equation, and see what happens. The intensity of the single at 80% goes back to 80%. So, it would be:

Square Root ( Weight/actual 1rm * Brzycki 1 rep max/ actual 1 rep max)

or

Square Root (Weight * Brzycki 1 rep max)
-------------------------------------------------------------
Actual 1 rep max


Here's my results. I used w*36/(37-r) for my Brzycki calculation.


Reps Adjusted intensity
1 80%
2 81%
3 82%
4 84%
5 85%
6 86%
7 88%
8 89%
9 91%
10 92%
11 94%
12 96%

This matches better my experience. If I did 80% of my 1rm squat, by the time it got near double digits I would be approaching my limit.

I hope this makes sense.

[ianmcginley]

Because, I'm not so familiar with the cyclists calculations, but they're always measure the cyclist quality by watts per kg. And 6.5 watts/kg counted as Elite level...
So how is it possible that someone with 150kg power clean who weighs 140kg is MUCH "better" than elite cyclists in term of power?
My guess is that they measure it by, for example, how much watts per kg you can generate for an hour, and not for a "single rep". But I really don't know, and it's possible that I said quite much bullshit.

I'm not Rip, but you are correct in your assumption over an hour period. Google for "Power 411", you'll find extensive information about cycling and power. Additionally under that page you will find information about Power Profiles.

Some details:
International (World Class) athletes at the top of their game in the various disciplines (track sprinting, pursuiting, road time trials, etc) give the following numbers as power/kg average for a duration:

5 seconds = 24.04W/kg
1 minute = 11.50 W/kg
5 minutes = 7.60 W/kg
Functional Threshold (effectively 1 hour) = 6.40 W/kg

[partyb]

I'm sorry, but all that math confused me almost immediately so I just went outside to my garage and did squats instead, adding weight since the last time I did squats.

[TinyArnold]

1.

if single rep is 100%
2 reps at 95% would be 95% and 100% ?
3 reps at 92.5% would be 92.5%, 9X% and 100% ?
4 ...

Somehow i get an impression that this is going to be complicated and "physics as you go" approach will not work - or at least, just recording data of response of your body to specific intensity&volume combination would be more useful.

2. W/s (watts/second) or J/s/s (Joules/second/second) is the rate of change of energy consumption or the rate in which the power changes. So Power IS just Watts.

[TalEphrat]

Thank you all for the replies.
I understand now the power issue, but I'm still struggling with the intensity issue.
Because not all of you understood why it's important - it's not important to someone who train only at the gym for strength, because he can use conventional programs until he is very, very strong. But for athletes who train, for example, in 3 disciplines except the strength training, to control the intensity as best as possible, can be a game changer.

Anyway,
You were right, to double percentages in percentages isn't the ideal. So I thought about calculating the intensity as the weight used compared to the maximal weight FOR THE SAME NUMBER OF REPS.
For example, if my RM5 is 150kg and I did a set of 5 with 130kg - than it's (130\150)*100 = 86.67%
But, because we want to measure how heavy we trained, and RM20 is not the same thing as doing RM1 in terms of adaptations and the things it demand (RM20 is more difficult but it's MUCH lighter than RM1 - it demand and create diferrent adaptations), than I thought we can make an average between the absolute intensity (weight/RM1) and the "set intensity".
So a 130kg for 5 reps when the RM5 is 150kg, and the RM1 is 174kg (by Brzycki suggestion - RM5/0.86=RM1. If the RM1 is known, it's better to use it) would be:
(130/150)*100 = 86.67%
(130/174)*100 = 74.71%
(86.67% + 74.71%)/2 = 80.69%

To be honest - it looks like a great way to measure intensity. What do you think?

[Mark Rippetoe]

I think what Karl thinks.