When you read "Run 25% slower than 5K pace" how do you interpret?

Using "Canova math," you'd go with option A.

Whether it's "right" or "wrong," mathematically, when you read through Canova's stuff, it's clear he uses whatever race pace as "100%" then uses (RP in seconds)*1.05 to get "95% of race pace", RP*1.10 to get 90%, and so on.

If you prefer to use Option B, more power to you- but if for whatever reason you're looking at other runners' workouts or recommending something to someone you coach, just make it clear how you're doing your math. If you send out a ~15:30 5k runner to do a 90min run at 85% of 5k pace, you'd better explain which 85% you want!

For what it's worth, I think option A is the convention among runners. I think the poster "MPR" used to use Option B for some of his marathon workouts, but you'd have to check with him- I'm pretty sure it's Mark Hadley, coach and dad of Alana Hadley. In my experience, A is vastly more common.

How is B, which is 33% slower, literally 25% slower? Explain it for the slow kids in the room like me.

Since about a year ago Renato has started using normal math.

ibemissingthepoint wrote:

How is B, which is 33% slower, literally 25% slower? Explain it for the slow kids in the room like me.

I'll use 50% slower to illustrate:

5:00 x 1.5 = 7:30

5:00 / .5 = 10:00

In my mind, 50% slower means "half the speed". A person running 10:00 miles would cover 50% of the distance of someone running 5:00 miles.

So you're saying that if I told you to run 100% slower than race pace, you would run (Race Pace x 2). I would say that 100% slower means you are not moving.

Surely....

5min/mile = 12mph

95% of 12 = 11.4mph

11.4mp = 5.15min/mile pace

mmm... wrote:

Surely....

5min/mile = 12mph

95% of 12 = 11.4mph

11.4mp = 5.15min/mile pace

That's just option B, but you converted the pace into mph and back again for some reason....

11.4mph = 5:15.78947 BTW

The only way the term 25% slower makes any sense to me is if you cover 25% less distance in the same amount of time. So that would be 6:40 pace.

Whilst your reasoning is sound mathematically, I think that using the option where 25% slower is simply 1.25 x pace makes more sense with regards to running. The reason being that as you said, 100% slower is stationary if taken in the literal sense, which is silly.

The exponential nature of the way you are calculating the pace makes it so that if you ask a runner to run 50% or 75% slower than they usually do, they will be running uselessly slowly.

Anyways, it's a stupid way to tell someone a pace. Speed is a ratio of time and distance. You either have to increase time by 25% or decrease distance by 25%. But I guess since we generally say min/mile time is the dominant unit and should be the one the 25% is focused on?

Agreed.

I just know I have had coaches in the past that would say say precisely: "I want you to run at about 65% of your max today."

I would say, WTF?

Say I'm training for the mile and my PR is 4:20. I assume that's my max.

Based on one interpretation, I'm running 5:51 pace, on another it's 6:40 pace. That's a huge range. Why not just tell me to run at one or the other?

Sadly, I think a lot of coaches just throw this terminology around without much explanation.

I have to disagree with the British fellow's reasoning. Another example:

It's well known that many Kenyan marathoners that average 4:45 on race day do easy runs in the 8-9 minute range.

Using your example, you would say that they are running at 70-90% slower than RP. I have never heard someone recommend that you do your easy runs at 75-90% slower than race pace.

I would argue they are going 40-50% slower.

Lenny Leonard wrote:

[quote]ibemissingthepoint wrote:

I'll use 50% slower to illustrate:

5:00 x 1.5 = 7:30

5:00 / .5 = 10:00

In my mind, 50% slower means "half the speed". A person running 10:00 miles would cover 50% of the distance of someone running 5:00 miles.

So you're saying that if I told you to run 100% slower than race pace, you would run (Race Pace x 2). I would say that 100% slower means you are not moving.

I don't understand that point of view at all. I think it makes more sense to use whatever percentage applied to original figure. What's 100% of 5:00 min/mile? 5:00 min/mile. So if I slow down by 100%, I slow down by how much? 5:00 min/mile. So what pace am I running? 10:00 min/mile.

I can see what you are saying. On a side note, I do think 8-9 mins is a bit exaggerated though. I'm sure that those runs aren't real training runs as such, i.e taken out of context. I'd accept they run as slow as 7mins on easy runs. From a scientific point of view, 8-9mins is a bit 'too' slow to work as aerobic training stimulus.

I think as long as the runner and coach are on the same page then it doesn't really matter what terminology is used.

800m Brit wrote:

From a scientific point of view, 8-9mins is a bit 'too' slow to work as aerobic training stimulus.

The concept of 'aerobic training stimulus' is not scientific. It's just something people say.

Wow, this is actually a great post.

Here is how I calculate training intensities (not sure if it's correct or not).

7:41 (RP/.65) Easy Pace that I use

6:15 (RP/.80) * tempo run pace

5:33 (RP/.90) * 10k/5k XC pace

5:00 (3200m Track Race Pace)

4:32 (RP/1.10) *roughly mile pace

4:10 (RP/1.20) * roughly 800m pace (2:05)

I don't think of this sign (/) as division, but as a FRACTIONAL RELATION, so 4:32 is race pace plus .10 faster than Race Pace; 5:33 is only .9 of the pace of the race.

Does this look right?

Well, it's something that scientists say.

http://www.gssiweb.org/Article/sse-54-muscle-adaptations-to-aerobic-training

another though wrote:

Lenny Leonard wrote:

[quote]ibemissingthepoint wrote:

I'll use 50% slower to illustrate:

5:00 x 1.5 = 7:30

5:00 / .5 = 10:00

In my mind, 50% slower means "half the speed". A person running 10:00 miles would cover 50% of the distance of someone running 5:00 miles.

So you're saying that if I told you to run 100% slower than race pace, you would run (Race Pace x 2). I would say that 100% slower means you are not moving.

I don't understand that point of view at all. I think it makes more sense to use whatever percentage applied to original figure. What's 100% of 5:00 min/mile? 5:00 min/mile. So if I slow down by 100%, I slow down by how much? 5:00 min/mile. So what pace am I running? 10:00 min/mile.

Here's the winning answer.

You can actually slow down MORE than 100% and still be moving.

What a thread.

This is why the Kenyans are winning.

The problem is you are - i think - looking at the wrong thing.

Velocity is what we are measuring.

If I remember correctly it includes displacement and direction. Minutes does not reflect either position. So you have to convert the time:distance ratio to MPH or M/sec and then do the manipulations.

It becomes obvious then which direction you want to go --faster or slower.

5:00 1600m = 1600/300 ===> 5.33... m/sec.

multiplying 5.33 x .75 and you get 3.975 m/sec. This is obviously slower and if that is the direction you want then you have the right number. Since multiplication and division are reciprocal you can divide: 5.33/.75 = 7.1111 m/sec. That is obviously faster. If that is what you want to do, then you have the right number.

The equation 5/.5 is a ratio only. An expression of the relationship of the two sides. It does not involve velocity. Runners and coaches are concerned with velocity.

I think...