Your Running Zones Are Wrong in the Pool, and 6A Is Not 6a

Is 1:49 per 100 a fast swim? It depends on a word most people leave out. Per 100 yards, it is the pace of a 1,650-yard swim done in exactly 30 minutes. Per 100 meters, it is about ten seconds per 100 quicker than that, and over an Olympic-distance triathlon swim the difference adds up to 2:33.

Swimmers, triathletes and climbers all carry numbers from one place to another: from a yard pool to a meter race, from a running watch to the pool, from a gym in Colorado to a crag in Spain. Most of those numbers do not survive the trip unchanged, and the beliefs that grow around them are worth checking. Below are seven that come up again and again, each held against what the Swim Pace Calculator, the Climbing Grade Converter and the Swimming Heart Rate Calculator actually return. One more turns out to be true.

Seven myths about swim pace, laps, heart rate and climbing grades

Myth 1: 100 yards and 100 meters are close enough

A yard is 0.9144 meters, so 100 yards is 91.44 m. That sounds like a rounding error. It is not: every pace per 100 yards is about 9% faster on paper than the same effort per 100 meters.

Fact: a swimmer's mile of 1,650 yd in 30:00 is 1:49.1 per 100 yd, which is 1:59.3 per 100 m. Planned as 1:49.1 per 100 m, a 1,500 m race would take 27:17. At the real pace it takes 29:50.

The table converts five common paces from a yard pool into meters and shows what they mean on race day, where every triathlon swim is measured in meters or miles. The race columns assume the pool pace holds all the way, with no wall to push off every 25 yards, so read them as the best case.

The fix is boring and reliable: type the unit of the pool you actually swam in. The calculator prints the pace in both units, so there is nothing to convert by hand and nothing to forget.

Myth 2: a mile in the pool is 66 laps

It is, sort of. US pool workouts use a swimmer's mile of 1,650 yd, which is 66 lengths of a 25-yard pool. A real mile is 1,760 yd.

Fact: a full mile is 70.4 lengths of a 25 yd pool, 64.4 of a 25 m pool and 32.2 of a 50 m pool. And if your plan counts there and back as one lap, every one of those numbers halves.

The word lap causes as much trouble as the mile. Some swimmers mean one length, end to end; others mean down and back. The calculator counts lengths and says so. Here is how the common distances come out in the three pool sizes:

Each of these has a ready page with the pool lengths already worked out and the time at six different paces: 500 yards, 1000 yards, 1500 yards, 1650 yards and 2000 yards for yard pools; a 400m swim, 750m, 1000m, 1500m and 2000m for meter pools; and in miles a quarter mile, half a mile, a mile, 1.2 miles and 2.4 miles.

Myth 3: your CSS is your race pace for any distance

Critical swim speed, worked out from a 400 and a 200 time trial, is the swimmer's version of threshold. A 400 m in 6:00 and a 200 m in 2:52 give a CSS of 1:34 per 100 m: the 188 seconds between the two swims, divided by two. It is a great anchor for training. The coaching convention used by Effortless Swimming hangs the sets around it: easy at 1:42 to 1:44, steady at 1:38 to 1:41, speed work at 1:29 to 1:32.

Fact: in lab trials, critical speed could be held for only about 14 to 39 minutes, and a 200 and 400 test gives a faster figure than protocols with swims of 800 or more (Scott, Burden and Dekerle, Journal of Human Kinetics). At 1:34 per 100 m, an Ironman swim would take 1:00:31, well beyond that window. Plan the long race slower than CSS, not at it.

Myth 4: your running heart rate zones work in the pool

This is the one that quietly ruins a lot of swim training. A watch set up with running zones reads 150 bpm during a swim set as 83% of maximum, steady aerobic work. Easy, right?

Fact: the heart does not reach the same peak in the water. Twelve elite swimmers tested by Olstad and colleagues reached a maximum 6.7 bpm lower in front crawl than in running. Studies from the seventies found about 15 bpm in young swimmers (boys 184 against 199, girls 186 against 201), and triathletes and fitness swimmers came out 9 to 14 lower. For a 40-year-old with the 7-beat correction, the same 150 bpm is 87% of the water maximum, which is vigorous work.

Why is the ceiling lower? The authors list the usual suspects: you swim lying flat, mostly with your arms, carried by the water, with restricted breathing. Less muscle is working at once, so the heart has less reason to go flat out. The size of the gap varies a lot from person to person, which is why the calculator offers three corrections and a measured maximum rather than one magic number. For a 40-year-old with no test (land maximum 180 bpm from 208 - 0.7 x age), the bands come out like this:

Look at the top of the moderate band: 135 on land, 130, 126 or 124 in the water. A swimmer holding 135 bpm because the running zones call it easy is already in the vigorous band. Better still, measure the maximum in the pool with a step test and skip the correction altogether.

Myth 5: Font 6A and French 6a are the same grade

Same digit, same letter, and the guidebook does not always help. But one is a boulder grade and the other a route grade, and they sit far apart.

Fact: a Font 6A boulder problem compares to a route of about 6c+, and it is a V3 on the American boulder scale. A French sport route of 6a is a 5.10a. The capital letter is the only warning, which is why British guides write route grades as f6a.

The pairs that confuse people most, side by side:

The converter has ready pages for the boulder grades people search for most: Font 6A, 6B, 6C, 7A, 7B, 7C and 8A on the V scale, and the other way, V7 and V10 in Font.

Myth 6: a grade converts exactly, row for row

Conversion charts look precise: one row, one grade per column. That neatness hides gaps. The scales do not have the same number of steps, so some grades fall between two of another scale's.

Fact: between 5.10a and 5.12a, YDS counts nine grades, and the RockFax and theCrag table leaves two of their UIAA cells empty. The converter writes those as A/B: 5.11a is VII+/VIII- UIAA. Charts also disagree with each other most between French 6a and 7a, where some put 6b at VII- and others at VII. Treat a converted grade as the same band of difficulty, not the same climb.

The most searched route conversions each have their own page: 5.10a, 5.11a, 5.12a and 5.13a in French, and UIAA 6, UIAA 7 and UIAA 8 in French and YDS. A UIAA VII, for example, is a 6b, or 5.10c.

Myth 7: a British E-grade tells you how hard the moves are

Partly. The British trad grade has two parts: an adjectival grade such as E3 for the overall seriousness, and a technical grade such as 5c for the hardest move. E4 is usually paired with 6a; an E5 6a has the same moves with less protection.

Fact: The Indian Face in Wales, the first route given E9, is only 6c technically, which the comparison table puts beside 5.13a. The E9 is about the fall, not the crux. That is why the converter marks its British column as indicative and assumes a typical, reasonably protected route.

One myth that is true: at the top, the scales agree

Climbers often say that above a certain level the grades simply line up. They do. From about 5.12a, French 7a+ and UIAA VIII+ upward, sport climbing took over and the French, YDS and UIAA columns of the table match almost exactly. Ewbank follows them one number per grade: 5.12a is 24, and 5.14a, French 8b+, is 32, the grade of Punks in the Gym at Mount Arapiles, the first route in the world at 8b+. The disagreement lives in the easier grades, where the scales grew up on different rock with different habits.

The only rule that holds for all three

Every number on this page was right where it was born and wrong somewhere else: a pace in a yard pool, a mile in a log book, a heart rate zone set up on a run, a grade in a guidebook from another country. Before you compare a number, check where it came from and convert it there, not after. Pace per 100 in the unit of the pool, laps counted as lengths, a heart rate maximum from the water, and a grade read with its letter case. Do that, and the numbers start telling the truth again.

Tools discussed in this article

• Swim Pace Calculator
• Climbing Grade Converter
• Swimming Heart Rate Calculator

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