Send-Off vs Rest Interval in Swimming

Use a send-off when the clock cycle is part of your training goal; use fixed rest when the recovery duration matters more than total cycle time. A send-off measures start to start, while a rest interval measures from your finish to your next start.

What changes between a send-off and fixed rest?

A send-off fixes your departure schedule. On a two-minute cycle, starting at 0:00 means subsequent departures are at 2:00, 4:00 and 6:00, regardless of your swim time. Fixed rest instead fixes the gap at the wall: touch, count the prescribed recovery, then leave again.

Two timing contracts

What is controlled?	Send-off	Fixed rest
Next departure	Previous start + cycle	Previous finish + rest
If you swim faster	You get more rest	You get the same rest
If you slow down	Your rest shrinks	Your next departure moves later
Clock task	Track scheduled starts	Read the finish, then add rest

USMS uses “@” for send-off notation and explicitly labels rest when recovery is intended. Read the whole instruction: “@2:00” as a send-off includes swimming; “2:00 rest” begins after the swim. For other abbreviations, see how to read a swim workout.

How do 6 × 100 on 2:00 and 6 × 100 with :20 rest compare?

They match only at a repeat time of 1:40. These two illustrative main sets use the same distance and steady effort; choose one after warming up, then finish your session with an easy cool-down. The two-minute cycle is an example, not a pace target everyone should meet.

Send-off example: 6 × 100 on 2:00

Illustrative main set, after your warm-up · 600m total

6 × 100m Steady freestyle — GA1 · Leave every 2:00 between repeats · Start every two minutes. Use only if this cycle leaves usable recovery at your steady pace; adjust it otherwise.

Fixed-rest example: 6 × 100 with :20 rest

Alternative main set, not an additional set · 600m total

6 × 100m Steady freestyle — GA1 · Rest 20s between repeats · Rest 20 seconds after touching the wall between repeats. No final rest is included in the finish-time calculation below.

The calculations below assume all six repeats take the same time, with no missed starts. “Finish” means the final touch, measured from the first push-off: five send-off cycles plus the last swim, or six swim times plus five fixed rests. These are calculated examples, not observed training results.

Calculated recovery and finish times

Time per 100m	2:00 send-off Rest between repeats; final touch	:20 fixed rest Rest between repeats; final touch
1:30	:30 rest; finish 11:30	:20 rest; finish 10:40
1:40	:20 rest; finish 11:40	:20 rest; finish 11:40
1:50	:10 rest; finish 11:50	:20 rest; finish 12:40
2:00	No rest; finish 12:00	:20 rest; finish 13:40

For scheduling, six complete two-minute slots occupy 12:00, including the remainder of the last cycle. If you also count a final 20-second rest in the fixed-rest version, its totals become 11:00, 12:00, 13:00 and 14:00 respectively. State whether that final recovery is included before comparing a plan’s duration with a watch recording.

At 1:50 per repeat, converting 20 seconds rest to a 2:00 send-off halves the available recovery. A 2:10 cycle would preserve 20 seconds only while you keep swimming 1:50. Use the swim pace calculator to estimate repeat times, then check them against what you can actually sustain.

Which timing format fits your set’s purpose?

Start with the intended effort and recovery, then choose how to express them. USMS describes send-offs as useful for distance pacing and fixed rest for broken swims, while stressing that rest must suit the swimmer’s speed. Applying that principle gives these practical choices.

Choose by purpose

Aerobic pacing Use a manageable send-off to practise steady repeat times against a predictable clock. Fixed rest also works when you want a consistent pause and can let the set duration vary.
Threshold-style repeats Choose a cycle that leaves the planned short recovery at your intended pace. If slowing down removes that recovery, adjust the prescription with your coach. A tight send-off alone does not define a threshold effort.
Sprints and broken swims Use explicit rest when the recovery is a defining part of the task. Maximum-speed work needs enough recovery to preserve speed; a broken swim needs the stated breaks. Do not apply the example’s 20-second rest to every sprint set.
Mixed-ability lanes The same send-off gives faster swimmers more rest. Group similar paces or adjust cycle, distance or repeat count with the coach. Fixed rest equalises wall time, but swimmers will depart at different times, so agree lane order and spacing.
Solo lap swimming Fixed rest is simple when your repeat times vary. Choose send-offs if following a clock rhythm is part of your goal and you can consistently reach the wall with the intended rest remaining.

If clock reading is the obstacle, the swimming pace-clock guide explains how to follow departures. The decision here is what those departures should control: the full cycle or the recovery alone.

Which timing mistakes change the workout?

What should you check on a Garmin or other swim watch?

Keep the timing rule explicit when copying a set to a watch: “start every 2:00” and “rest :20 after touching” are different instructions. Check the workout preview and your particular model’s manual for how it represents each one. The sources here establish swimming terminology, not Garmin model compatibility or automatic-rest behaviour.

When reviewing a recording, compare swim time, wall rest and elapsed time separately. If the workout transfer cannot represent the intended rule, retain a clear written prescription and use the pool clock. In the AquaPlan free workout builder , keep the repeat distance, effort and recovery instruction together, then check the exported version before swimming.

Choose your timing rule

Use send-offs for the cycle; fixed rest for the recovery.

Preserve the purpose when you change formats. If your goal requires a dependable pause after every swim, keep fixed rest. If pacing against regular departures is part of the task, choose a send-off that leaves the intended recovery at your pace.

Frequently Asked Questions

Does @2:00 mean two minutes of rest?

When used as a send-off, @2:00 means start a repeat every two minutes, including swimming and rest. A 1:40 swim leaves 20 seconds at the wall. If the instruction explicitly says two minutes rest, that recovery starts when you finish swimming.

Are a 2:00 send-off and 20 seconds rest equivalent?

Only while each repeat takes exactly 1:40. At 1:50 per repeat, the send-off leaves 10 seconds rest, while fixed rest still gives 20 seconds and moves the next start to 2:10 after the previous start.

What if I cannot make the send-off?

If you arrive at or after the next departure, there is no rest left in that cycle. Ask the coach to adjust the interval or distance; when swimming solo, choose a longer cycle that preserves the intended effort and recovery. Do not silently replace the prescription with a different timing rule.

Which format is easier for solo lap swimming?

Fixed rest is a straightforward starting point when repeat times vary: note your finish time and add the stated rest. Send-offs suit solo swimmers practising a steady clock rhythm. Neither format is automatically easier; the pace and available recovery decide that.

Sources and editorial process

Sources checked October 4, 2026. The USMS glossary supplies the notation; the two training articles explain timing definitions and choosing rest around set purpose. The 600m examples and elapsed-time calculations are illustrative applications of those definitions, not prescribed USMS workouts or first-hand testing.

Limitations: the timing examples assume steady repeat times and are not personalised training targets. No device model or export workflow was tested for this article.

Automated editorial check (daily-ai-v1): this article was authored using AI and checked through an automated editorial process. No human expert review is claimed.

Article publisher

Published and maintained by AquaPlan. The article above identifies its evidence sources and automated editorial process; no human expert review is claimed.