Quick answer
Almost every swimmer is slower in the second half of a 100; that alone is not "fading." To know whether your swimmer really fades, compare their splits with swimmers of the same age who finish in the same time. If their first 50 is slower than those peers and their second 50 is faster, the seconds to find are at the start of the race, not the end. That changes what the coach might work on, and what you ask after the race.
This article walks through a 100 free, split by split, to show how to tell the difference, and how to run the check on your own swimmer.
What a "Split" Is, in 30 Seconds
A swimming race is timed in pieces. In a 100, the two main pieces are the first 50 (block to turn) and the second 50 (turn to finish). Each piece is a split. At meets with electronic timing, splits are recorded automatically by the touchpads and usually appear in the official results.
From the stands you see one number on the scoreboard, say 1:01.46. The swimmer feels both halves, and the results file has both.
What Pacing Patterns Mean
Coaches describe how a swimmer divided the race in three ways:
- Positive split. First half faster than the second. By far the most common pattern in a 100, because the first 50 includes the dive.
- Even split. Both halves roughly equal.
- Negative split. Second half faster. Rare in a 100; more common in longer races swum with careful pacing.
Parents see positive splits and read them as fading. Sometimes that is right. Often it is not.
An Example: a 14-Year-Old and a 1:01.46
Take an illustrative example: a 14-year-old girl whose best 100 free in a 25-metre pool is 1:01.46:
| Her split | |
|---|---|
| First 50 | 29.88 |
| Second 50 | 31.58 |
| Total | 1:01.46 |
She is 1.70 seconds slower on the back half. The parent's natural conclusion: "she can't hold her pace, she needs more endurance."
That conclusion may be wrong. The only way to know is to compare her with the right group.
The Peer Comparison
Instead of comparing her with herself or with a generic chart, compare her splits with other swimmers about her age who finish in about the same time.
Suppose the average of those peers, all finishing around 1:01.5, looks like this (numbers for illustration):
| Her split | Peer average | Gap | |
|---|---|---|---|
| First 50 | 29.88 | 29.10 | 0.78 slower |
| Second 50 | 31.58 | 32.36 | 0.78 faster |
| Total | 1:01.46 | 1:01.46 | same |
Swimmers who finish in the same time will always balance out: if she is slower in one half, she is faster in the other. The question is which way round. Here, she is slower at the start and faster at the finish than her peers. She is not fading more than they do. She is starting slower.
If the table were the other way round (a faster first 50 and a slower second 50 than her peers), then fading really would be the issue.
For broader context on what "fast for her age" means, see is my swim time good for my age?. The peer comparison is a sharper version of the same idea, narrowed to swimmers who finish in the same time.
Why the Diagnosis Matters
The two readings point to different conversations with the coach:
If she really fades (second 50 slower than peers), the work is usually about the back half: aerobic base, race-pace sets, holding speed when tired.
If she starts slow (first 50 slower than peers), the work is usually about the front of the race: the dive and reaction, underwater kicks, breakout, first turn.
Same swimmer, same time, two different focuses. Without the comparison, parents and coaches tend to focus on whichever half looked worse from the deck, and that is almost always the second half, where the swimmer is visibly working hardest. The first 50 happens fast and looks "fine" even when it is the slow one.
What Changes in Practice (and at Home)
The coach conversation changes from "she needs to hold the second 50" to "her first 50 is behind swimmers her age at the same time. Can we look at the start and the first turn?" The coach decides what to do with that; the data just points where to look.
At home, the question after a race changes from "how was your endurance?" to "how did the start feel?"
And the swimmer's self-talk changes from "I died at the end" to "I left time at the start." Same race, more accurate words, and a lighter emotional load. For which "best" matters when, see Season Best vs Personal Best: What Counts.
How to Run This Check on Your Own Swimmer
In Gophin, the Times → Splits screen does this for you:
- Open Times → Splits and pick your swimmer.
- Choose a race that has official splits, such as a 100.
- Open the Find time tab and enter the time your swimmer is chasing.
Gophin compares the race with swimmers born within a year of yours who swam within about 5% of the same time in the last 24 months, points out the split with the biggest gap to that group, and lets you drag a slider on any split to see the projected total. You can also compare against up to three swimmers you choose. It is free for every event and distance.
Prefer to do it by hand?
- Find the swimmer's time and splits in the meet results.
- Find several swimmers of the same age who finished in about the same time at recent meets. The USA Swimming times database and Swimming Canada's rankings let you search by event and age.
- Average their first 50s and their second 50s.
- Compare each with your swimmer's. The half where your swimmer is slower than the group is the one to look at.
For a broader look at reading splits, see how to read swim splits.
What This Approach Does Not Tell You
The peer comparison answers "where in the race is the gap?" It does not answer "why?" The why might be:
- A short underwater kick off the start
- A slow turn into the second 50
- A breathing pattern that costs speed early
- A stroke issue in one half specifically
- Nerves at the start that settle by the second length
Those are questions for the coach's eye and video, not for data alone. The splits tell you where to look; the coach tells you what is happening there.
Quick Decision Guide
- "Did she go out too slow or come back too slow?" Compare both halves with swimmers of the same age and final time.
- "What do I raise with the coach?" The start and first turn if the first 50 is behind; the back half if the second 50 is behind.
- "What do I ask after the race?" Start with "how did the start feel?"
- "Where do I find peer data fast?" The Find time tab in Times → Splits in Gophin.
- "What if there are few peers at her exact age and time?" Widen the group a little (a year either side, a slightly wider time range). The comparison still works.
One Last Thing
If your swimmer seems to be "fading" in the second half, the next question is not "how do we build endurance?" It is "how does the first half compare with swimmers their age who finish in the same time?" Often the answer is that there is more time to find at the front of the race.
The race you watched from the bleachers is not the same race the swimmer swam. The splits close the gap. Check your swimmer's splits in Gophin. Free.
