SCY vs LCM vs SCM: Why Your Swimmer's Times Look Different in Every Pool
Your swimmer just had what looked like a great meet. Their 100 backstroke time was a personal best by nearly two seconds. Then a few months later, at a different meet in what seemed like a similar pool, that same swimmer went almost three seconds slower in the same event — and came home in tears.
Nothing went wrong. No bad race. No off day.
The pools were just different sizes.
This is one of the most disorienting parts of competitive swimming for new parents, and it almost never gets explained at orientation night. This guide covers everything you need to know about the three pool types used in competitive swimming, why times are so different between them, and what it actually means when your swimmer's coach says "that's a great short course time."
The Three Pool Types in Competitive Swimming
Competitive swimming takes place in three different pool configurations, each with its own abbreviation:
SCY — Short Course Yards A 25-yard pool. The most common pool type in the United States for club, high school, and college swimming. Most of the fall and winter competitive season (September through March) takes place in SCY pools.
LCM — Long Course Meters A 50-meter pool — the Olympic standard. Used for summer competition in the US and for international meets year-round. When you watch the Olympics, you're watching LCM.
SCM — Short Course Meters A 25-meter pool. Less common in the US than the other two, but used for some national championship meets and internationally. World Aquatics World Short Course Championships and many national championship events use this format.
Most American age group swimmers primarily compete in SCY during the school year and LCM during the summer. SCM appears less frequently but does come up, particularly at higher levels of competition.
Why Times Are So Different Across Pool Types
This is the part that trips parents up most. Your swimmer didn't suddenly get faster or slower. The pool changed.
Here's the key: walls are free speed.
Every time a swimmer reaches the end of the pool, they execute a flip turn and push off the wall. That push-off launches them into an underwater streamline — a position that is hydrodynamically faster than surface swimming. Every time a swimmer reaches the wall, they push off with their legs, essentially getting a burst of speed that is faster than swimming.
The shorter the pool, the more often this happens. And more turns means more free speed, which means faster times.
Here's how the turn math works across pool types:
| Pool | Length | Turns in a 100 race | Turns in a 200 race |
|---|---|---|---|
| SCY (25 yards) | 25 yds | 3 turns | 7 turns |
| SCM (25 meters) | 25 m | 3 turns | 7 turns |
| LCM (50 meters) | 50 m | 1 turn | 3 turns |
A swimmer racing 200 yards in a short course pool gets seven push-offs. That same swimmer racing 200 meters in a long course pool gets three. Those four extra turns add up to a meaningful time advantage — roughly 2% per 100 meters when comparing SCM to LCM.
This is why your swimmer's short course times will almost always look faster than their long course times, even when they're swimming just as hard.
The Yards vs. Meters Complication
The difference between SCY and SCM adds another layer of confusion, because a 100-yard race and a 100-meter race aren't the same distance.
100 SCY equals 91.44 meters, while 100 SCM or LCM equals 100 meters. So a 100 "freestyle" in a yards pool is actually about 9 meters shorter than a 100 freestyle in a meters pool.
That's why SCY times often look dramatically faster than LCM times — they're combining the shorter pool distance advantage and the extra turns advantage. A 100m in SCY is typically 2–3 seconds faster than in LCM.
As a rough rule of thumb: to estimate what a SCY time might look like in LCM, multiply by approximately 1.11. For example, a 100-yard freestyle in 50.00 seconds would convert to roughly 55.50 seconds in LCM. This is an approximation — actual conversion varies by stroke, distance, and how strong the swimmer's underwater work is — but it gives you a ballpark.
Which Pool Type Is Used When
For most age group swimmers in the US, the competitive calendar breaks down like this:
Fall and Winter (September – March): Short Course Yards (SCY) The bulk of the USA Swimming age group season takes place in short course yards pools. Club dual meets, invitational meets, LSC Age Group Championships, Zone Championships, and most Sectional meets during this period are SCY. This is the dominant format in American college and high school swimming.
Summer (April – August): Long Course Meters (LCM) Summer is long course season. Club summer meets, LSC summer championships, and the national summer championship meets (Futures, Junior Nationals, Toyota Nationals) are all contested in LCM. This is also when swimmers who are eyeing international competition get the most relevant preparation.
SCM: Situational Short course meters appears at specific national and international events, but most age group swimmers encounter it infrequently. If your swimmer's coach mentions an SCM time, it's usually in the context of a converted time or an unusual meet format.
Why Your Swimmer's Best Time "Doesn't Count" for Some Meets
Here's a practical consequence of all this that frustrates many swim families: a swimmer's personal best in one course type usually cannot be used to qualify for a championship meet held in a different course type.
If your swimmer's Age Group Championship is held in an SCY pool, the qualifying cut is an SCY time. A strong LCM time from summer meets — even a genuinely fast one — won't satisfy the SCY qualifying standard. The meets are simply different events held in different pools, and the standards are set independently.
Some meets do publish converted qualifying times that accept performance from a different course, but this varies by meet and LSC. Always check the specific meet information. When in doubt, ask your swimmer's coach which course the qualifying time needs to come from.
How Strokes Are Affected Differently
Not all strokes benefit equally from short course pools. The size of the turns advantage varies by stroke because of how swimmers come off the wall.
Backstroke and butterfly tend to benefit most from short course pools. These strokes allow for extended underwater dolphin kick phases after each turn — a highly efficient position that produces fast split times. A strong underwater kick can essentially carry a swimmer several meters off every wall, and in a short pool, those meters add up quickly.
Freestyle benefits significantly too, particularly for swimmers with strong flip turns and tight streamlines.
Breaststroke benefits the least from short course, because breaststroke underwater pullouts — while meaningful — are shorter and less dramatic than the dolphin kick phases in the other strokes. The conversion factor for breaststroke between course types tends to be smaller.
This is why some swimmers appear to be exceptionally strong in short course and merely good in long course, or vice versa. It's not necessarily fitness — it can be a reflection of how well their particular stroke translates across pool types.
What This Means for Tracking Progress
The practical upshot for swim parents: when comparing your swimmer's times, you need to compare apples to apples.
A 1:02 in the 100 backstroke SCY is not the same as a 1:02 in the 100 backstroke LCM. They're different events in different pools. Comparing them directly — or being disappointed that a long course time is "slower" than a short course time — misreads what the times actually mean.
The right way to track progress is to compare SCY times to SCY times, and LCM times to LCM times, within the same season or across equivalent seasons from prior years.
Qualifying standards reflect this too. USA Swimming publishes separate standards for SCY, LCM, and SCM — so an AA standard in short course yards is a different number than an AA standard in long course meters. Both represent the same level of achievement relative to national peers, just in their respective pool types.
This is one of the core design decisions in SwimTrack: your swimmer's times are tracked separately by course type, so you're never accidentally comparing a summer long course best to a short course qualifying standard. The app automatically matches your swimmer's times to the right standards for the right pool — and shows you the gap in real time.
Quick Reference: SCY vs LCM vs SCM at a Glance
| SCY | LCM | SCM | |
|---|---|---|---|
| Pool length | 25 yards | 50 meters | 25 meters |
| US season | Fall/Winter | Summer | Occasional |
| Olympic format? | No | Yes | No |
| Turns per 100 race | 3 | 1 | 3 |
| Times vs LCM | Faster (~11% less distance + more turns) | Baseline | Faster (~2% more turns) |
| Common meets | Club meets, LSC championships, Sectionals SCY | Summer club, Futures, Junior Nationals | Specific national/international events |
Common Parent Questions
My swimmer dropped two seconds at the last meet — is that a real improvement? Check which pool type the meets were in. If they moved from LCM to SCY, some of that drop is expected based on the course difference. If both meets were in the same course type, it's a genuine improvement — celebrate it.
The qualifying cut says 1:05.00 but my swimmer went 1:03 last summer. Why can't they enter? Almost certainly a course type mismatch. If the championship is SCY and your swimmer's 1:03 was in LCM, those are different events. Your swimmer needs a 1:05 or better in an SCY pool to qualify. Check with your coach if you're unsure which course a time was swum in.
Can coaches use a summer LCM time to predict short course times? Yes, though not perfectly. The standard conversion approximation — multiply SCY by ~1.11 to estimate LCM — works as a rough baseline. Stroke technique, turn quality, and underwater ability all affect how well a particular swimmer converts between courses. Your coach will have a feel for whether your swimmer tends to be a stronger short course or long course racer.
Why does the US use yards when the rest of the world uses meters? It's a historical quirk of American pool infrastructure. The use of yards rather than meters is unique to American pools and dates back to when most US facilities were built in 25-yard configurations. The college and high school systems built around those pools, and the infrastructure stuck. Most US club pools are still 25 yards, which is why SCY dominates the domestic age group season.
SwimTrack tracks your swimmer's times separately by course type — SCY, LCM, and SCM — and compares them against the right qualifying standards automatically. No more wondering if you're comparing apples to oranges. Download free at swimtrackapp.com.