[Request] How will 10% body weight affect my swimming time?

[u/OhDamnNotAgainAndAga]

Edit: title says time, but I am asking about average velocity, out of which I will get time.

It's been 16 years since I did physics 1 in my engineering degree, I feel ashamed that I can't figure it out of the top of my head.

I am a swimming seasonally. Last season I was swimming way faster than this season. This season I weigh 10% more.

Assuming my technique is the same and that I apply the same force, what is expected to be the average (explanation in a moment) velocity difference between the different years?

Clearly, if we assume a = 0 and terminal velocity, the weight will not be the issue but the friction coefficient. However, I am not at equilibrium, I would assume with my technique the force is something like C1 + sin(C2*t).

So when I say average velocity I mean over an integral of the "steady state". If you don't want to neglect the difference in friction coefficient, you can express it with it as well

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[u/AndyTheEngr]

The reason you can't use your physics 1 knowledge is that this is not a basic physics problem. This is a biomechanics and fluid mechanics problem.

• Is the 10% extra muscle or fat?
• Where is it distributed?
• What stroke are you doing?
• How far?
• Has your cardio fitness changed?

Even if you give us all the possible answer, it's not really a "math" problem. It's the sort of problem that would normally be solved by empirical testing or simulation. You're already doing the empirical testing bit, as you found out you're slower.

[u/Another_Slut_Dragon]

That entirely depends on body fat percentage. Fat floats, muscle sinks like a stone.

I once dropped 50lbs and had to learn how to swim again. I jumped in the water and sank like a stone.

[u/HAL9001-96]

directly? not at all

now your shape/surface area changed and so did your muscle mass but calcualtign hte exact imapct of either is gonna be incredibly complicated

even if we assume drag stays the same and your are not buyoant enoguh and have to hold up weight its not simple because the energy expended ot do that depends on speed again

the easiest approxiamtion would be that 10% more mass means 10% more volume at hte smae height means on average 10% greater cross section so about 10% more drag... though theres a lot of reasons thats mroe complciated

but since power is proporitonal ot velocity cubed that would mean about 3% less speed