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Convert a 40-yd or 100-yd Dash Time to MPH?

# Convert a 40-yd or 100-yd Dash Time to MPH?

If you have a 100-yard dash time, divide it into 205 to get an approximate miles per hour speed.

So, if you have a 10 second 100-yard dash, you are going about 20.5 mph. If you have a 14 second 100-yard dash, you are going about 14.6 mph. If you have a 12 second 100-yard dash, you are going about 17 mph. An 8 second time? About 26 mph.

If you have a 40-yard dash time, divide it into 80 to get an approximate miles per hour speed.

So, if you have a 5 second 40-yard dash, you are going about 16 mph. If you have an 8 second 40-yard dash, you are going about 10 mph.

1. bob

what do you mean “divide it into”? Divided by?

1. Michael Gold

It means to divide 205 by your time. So, of course, a 10-second time would be 205/10 = 20.5 mph.

Make sense now? Any other questions I could answer?

I hope all is well with you.

2. Brian Chapman

This method overlooks the time needed to accelerate. It would be legit if both sprints were from a running start, but the 40-yd sprinter has a disadvantage here since a greater portion of his sprint is spent accelerating to his top speed.

1. Michael Gold

Thank you for the response and for bringing up that point!

But “overlook” has (at least) two meanings here:
1. to neglect for purposes of simplifying an analysis, while maintaining the various contexts involved;
2. to not remember to consider or to not know to consider.

I did the first.

I am aware of acceleration. I am also aware of other factors that affect speed: ground conditions, nature of surface running on, terrain, elevation change, wind speed, sleep status, health status, nutrient status, mitochondrial function, age, recent workouts, etc.

While it would be fascinating to bring all those factors into play to get a multi-variate function for speed, it is no way to start, and not something to carry around for common use.

Yes, as Brian says, in some but not all contexts we should consider acceleration. Thanks!

3. thank you for that sir