Every coach has his/her own terms and abbreviations which can make it hard to understand a written practice. If the coach is available, ask him/her any questions you might have. As a coach, I might use different terms or abbreviations, I might use a drill you don’t know, or sometimes my handwriting is just horrible. I, and most Master’s coaches, am never insulted for clarification as I know master’s swimmers have very different backgrounds when they come to my program. I appreciate the curiosity and interested in my work. If the coach is not available, consider emailing them or any coach or long time swimmer for their ideas on what was meant.
One question I often get is on a common set such as 10×50 Fr on 1:00. What this means for my practices is that the swimmer should do 50 yards Freestyle, 10 times, starting 1 minute apart. Often this means starting on the 60 or “the top” and every 60 starting the next 50. This is a good set because if you start on the same time, you easily compare if you go faster or slower than the one before. Not every swimmer can repeat 50’s on a minute, so 2 minutes could also be used for the same experience. If you are getting good at reading the pace clock (it is a skill just like flip turns and butterfly kick that do improve with practice), then you can try other intervals like 1:30 or :50. To repeat 50’s on :50, try the first one on the 60, the second on the 50, the third on the 40, the fourth on the 30 and so on.
Some people have expressed that they thought on 1:00 meant taking one minute rest after you finish the 50, which also an option. In my practices, I will note this by saying 10×50 Fr with 1:00 rest. The advantage of practicing on an interval- leaving every 1:00 or 2:00 is that you are incouraged to swim fast so that you can have more rest. The advantage of having swimmers rest a specific amount of time between swims is that many different abilities can swim a set and not feel pressure to keep up with or slow down for the group.
Most important is that you do sets that you are comfortable with and can feel successful at even if you make up your own rules for them. This will encouraged you to keep swimming.