Mathematical Modeling of Attempt Selection | Jeff Russell

[K9ZAZ]

Yes, but hitting an attempt does not mean you can hit it 100% of the time

I never said that it did. What hitting the attempt does is tell you that the attempt does not exceed your 1RM, which is a useful piece of information. Missing, on the other hand, doesn't tell you a whole lot.

Due to this uncertainty, the idea of a definitive “1RM” isn’t accurate

The definition of a 1RM in this article is essentially the weight at which the probability of hitting it reaches 0; it's not really the definition others use, but it's related and is a useful one in this context.

The model espoused by the article says hitting a lift at weight w is like flipping a coin with bias f(w), where f is a decreasing function of w, and takes values in [0,1]. An accurate estimate of the bias requires flipping the coin a few times.

I know. I read the article.

[Shiva Kaul]

General impression is it would be very difficult to create a model that outperforms an experienced coach relying on lifter feedback before/after attempts.

I agree. I don’t think an algorithm would spit out good attempts, if only because the input data aren’t precise.

However, a mathematical analysis of the problem could help coaches think strategically about attempt selection. For example, coaches currently choose conservative 1st attempts. If an aggressive 1st attempt is proven superior within the model, then they may revise their selections accordingly, while still using their judgement and experience.

[Shiva Kaul]

I never said that it did. What hitting the attempt does is tell you that the attempt does not exceed your 1RM, which is a useful piece of information. Missing, on the other hand, doesn't tell you a whole lot.

I agree that hitting an attempt is more informative than missing for estimating one’s strength curve. Under the exponential model, it probably wouldn’t be hard to derive the optimal “query” attempts which would most rapidly estimate the curve.

All I was observing was: when lifters barely grind out a rep under the best possible conditions, they might call it their “1RM” with an undue certainty. The article is says that random outcome is not particularly informative, as a measure of strength, or as a data point to help choose attempts. It (provocatively) strips these lucky lifters of some glory.

[Mark Rippetoe]

Suppose that non-monotonic (i.e. currently illegal) attempt selection led to to substantially higher totals. Say, 3-5% higher. Would the practical benefits of the current rules be worth the hindrance of performance?

What is a non-monotonic attempt selection?

[K9ZAZ]

What is a non-monotonic attempt selection?

One where the first attempt would be higher than the second. Presumably only applicable if the rules changed and you tried a weight you weren't sure about for your first attempt, bombed it, then went back to a safe(r) weight for the second attempt.

[Shiva Kaul]

What is a non-monotonic attempt selection?

Attempts that don’t steadily increase, e.g. 310 -> 330 -> 320.

[Mark Rippetoe]

One where the first attempt would be higher than the second. Presumably only applicable if the rules changed and you tried a weight you weren't sure about for your first attempt, bombed it, then went back to a safe(r) weight for the second attempt.

Attempts that don’t steadily increase, e.g. 310 -> 330 -> 320.

If you guys are going to pull a shiny new word out of your asses, coordinate the definition first. What would be the purpose of allowing a meet to function as a training session?

[Shiva Kaul]

If you guys are going to pull a shiny new word out of your asses, coordinate the definition first. What would be the purpose of allowing a meet to function as a training session?

Allowing attempts to decrease (rather than just increase or remain the same) could allow lifters to hit higher totals via more rational attempt selection.
The optimal strategy for a 2-attempt meet decreases the 2nd attempt if the 1st was not hit; I haven’t analyzed the 3-attempt meet.

I think a meet allowing optimal attempt selection would be a better demonstration of strength. But as you mentioned, it would be more impractical to run.

[Mark Rippetoe]

Allowing attempts to decrease (rather than just increase or remain the same) could allow lifters to hit higher totals via more rational attempt selection.

This is precisely the effect of NOT allowing the 2nd attempt to be lighter. It encourages conservative attempt selection until the 3rd attempt. Have you ever been to a meet?

[Shiva Kaul]

I’m not sure I understand. Do you believe that the current rule, encouraging conservative 1st and 2nd attempts, tends to result in the highest possible totals? Or do you wish to encourage conservative, more-easily-repeatable attempts at the expense of performance?

The main question is: if dropping the rule led to higher totals, would USSF be in favor of doing so? I think either choice is justifiable.

I haven’t participated in a powerlifting meet, and that will remain true for roughly 3 weeks.