Swimming Glossary

Glossary of Swimming Terms

Base Interval – Cruise Pace (BI)

The base interval is the lane we practice in (e.g., the 1:20 lane) and the basis for all of our Send-Offs. For 100’s on +10, the 1:20 lane’s sendoff is 1:30, which is the base interval, 1:20, plus 10 seconds. For Mountain View Masters, the correct base interval will allow you to do 6 to 10 X 100 freestyle (about 10 to 12 minutes of swimming) on that interval at 80% of maximum heart rate with a couple of seconds rest per 100.

Note:  Send-offs for longer (and shorter distances) are calculated by adding the 100 Base Interval over the specified distance. The 1:30 Base Interval swimmer will swim 200’s on 3:00 (2x 1:30) and 400’s on 6:00 (4x 1:30).

Send-offs are often adjusted by adding or subtracting seconds from the Base Interval. Seconds are added to or subtracted from the sum of the Base Intervals, not to each 100 in the distance. For example an adjustment of -5 (minus 5 seconds) to the send-offs of a swimmer with a 1:30 Base Interval are the following: 100’s on 1:25, 200’s on 2:55 , 400’s on 5:55.

Samples of adjusted Send-offs for different Base Intervals:

Read down the column with your base interval for your adjusted send-off intervals.
Base Interval ->  1:15 1:20 1:30 1:45 2:00
1x 100 on cruise  1:15 1:20 1:30 1:45 2:00
1x 300 on cruise – :15 3:30 3:45 4:15 5:00 5:45
1x 100 on cruise + :05 1:20 1:25 1:35 1:50 2:05
1x 200 on cruise – :15 2:15 2:25 2:45 3:15 3:45
1x 100 on cruise + :10 1:25 1:30 1:40 1:55 2:10
1x 100 on cruise – :15 1:00 1:05 1:15 1:30 1:45

Best Average

Holding the best time possible for the number of repeats on the given interval. Usually a best average set will allow for a more rest, so you can swim at a faster pace. Your pace on a best average set should be faster than when you swim threshold, but not as fast as sprint pace.


The interval or time on which you begin each repeat (swim) of the set. For example, if you swim 4 X 100 on 1:30, the Send-off is 1:30. If you swim a 1:22 for the 100, you will have 8 seconds rest before you need to leave on the next send-off.

Warm up

The warm-up is almost always some version of 600 yards/meters. Swim this very easy in what will feel like slow motion swimming. Stop to stretch whenever you want. This is the time to adjust goggles, caps and what not.


The drill set is an extension of warm-up. There are rarely interval times associated with this set, so that you may focus totally on stroke technique without concerning yourself with speed or rest. Again, stretch as necessary and pay close attention to your body position and form. Allow your heart rate to come up slowly. You should get 10-15 seconds of rest between each part of the Drill Set.


The main set ranges in length from 1200 to over 2000 yds/mtrs. To modify the main set (or any set of the workout) for less distance, you may either decrease the distance in the repetitions or decrease the number of repetitions.

For example: a set of 10x 100 can be modified to 5x 100 or 10x 50 to arrive at a set one-half the distance.

If your water time is limited, avoid the temptation to eliminate the warm-up and/or drill sets. These are important for injury prevention, better stroke technique and the flow of the workout. Equally important is to leave time for a cool-down swim at the end of your workout!

Pattern Repeating

Often the workout will give you a pattern of strokes and/or drills and/or kicking to do over a given distance. Note that the pattern does not always equal the distance of the swim. You are being asked to repeat the pattern over the given distance. For example, the following set:

1x 300: 50 free / 25 back / 25 breast is asking you to swim the pattern of 50 free / 25 back / 25 breast as many times as necessary to complete a 300. In this case it is 3.

Swim to the Interval

Swim to the Interval is a general way of specifying that the swimmer pace himself through a swim such that he doesn’t go too fast (getting too much rest) or too slow (getting too little rest). The idea is to pace yourself properly to swim easy for an easy interval and to swim fast for a fast interval.


Descending sets ask you to swim each repetition faster than the previous. For example, the following set:

6x 50: Descend 1->6asks you to swim six 50’s with each one faster. If the set read:

6x 50: Descend 1->3, 4->6you are asked to descend the first 3 and the second 3 in the set. The fourth 50 should be slower than the third. The third and sixth are the fastest in the set. Unless specified, the interval stays the same, giving you a bit more rest as your swimming time descends.


Building is different from Descending in that the swimmer’s goal is to increase speed within the single swim distance(s). For example, the following set:

3x 100: Build asks you to swim each 100 starting easy (with perfect technique) and increasing speed within each 100 to a fast finish (maintaining perfect technique throughout). As you may have guessed, the goal in a “Build” swim is to build speed while maintaining good stroke technique.

Negative Split

Swimming a Negative Split means that the second half of the distance is swum at a faster pace than the first half. For example, the following set:

1x 600: Negative Split asks you to swim the second 300 yards at a faster pace and time than the first 300 yards. The idea is to control your pace at the beginning of the swim so that you have the energy necessary to swim faster at the end of the swim.

Transitional IM’s

These are IM repeats that work on the stroke transitions of the Individual Medley. The three transitions are fly -> back, back -> breast and breast -> free. The following set:

3x 100: Transitional IM would be swum: #1) 50 fly / 50 back, #2) 50 back / 50 breast, #3) 50 breast / 50 free. And the following set:

6x 50: Transitional IM would be swum #1-2) 25 fly / 25 back, #3-4) 25 back / 25 breast, #5-6) 25 breast / 25 free. This of course, could also be swum 1 of each transition, going through the pattern twice for a total of six repeats.

IM with alternate lengths Free

This is describes an IM swim with the even lengths freestyle. For example, a 400 IM with alternate lengths freestyle would be swum as: 25 fly / 25 free / 25 fly / 25 free / 25 back / 25 free / 25 back / 25 free / 25 breast / 25 free / 25 breast / 25 free / 25 free / 25 free / 25 free / 25 free.


A Pull-Out is a strength building exercise. It must be done in water at least 6 feet deep with the pool deck preferably much higher than the water level. Facing the wall, the swimmer will place his hands on the edge of the deck or gutter about shoulder-width apart. Without kicking, the swimmer will pull his upper body up and out of the water to the full extent of the arms. Once full extention is obtained, the swimmer will lower himself back into the water carefully.

Within a swim set, Pull-Outs are used to build upper body strength. For example, the set:

1x 200: Swim, on Cruise
10x Pull-Outs
1x 200: Swim, on Cruise

asks the swimmer to complete a 200 yard swim within his Cruise interval, then complete 10 Pull-Outs at the wall, and then progress to another 200 yard swim within his Cruise interval.


FUNS stands for Fly, Underwater, No breath and Sprint. One FUNS is 4×25 (25 Fly, 25 Underwater, 25 No breath and 25 Sprint) where you rest after each 25 and then go on for the next part of FUNS. FUNS is a favorite of all swimmers.

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