When I started to get seriously into swimming I was at a loss to interpret the jargon used by swim coaches to specify workouts. Things like this were as meaningful to me as a doctor's prescription.
300 smooth pull or swim:15 sec rest
200 2(50 fast heavy on legs,50 ez) :15 sec rest
100 change stroke ea. 25
4x25's fast heavy on legs or kick
4x50's add :10 sec #1 stay on pace
4x75 add :15 sec # 1 stay on pace
I have a bit more experience with running. Here is this morning's strides workout:
5 min 1Z
5 min 2Z
6 x (30 sec 4Z/1:30 1Z)
5 min 2Z
5 min 1Z
To put this into a really practical context, I start this workout on Kilauea Avenue close to the Aloha gas station, after getting a sip of water at the professional building next to the church preschool. I run on the east sidewalk headed south. The route is slightly downhill, which simplifies warming up. Five minutes gets me to a spot just past the elementary school where I can slip into Kahala Park, so the second half of the ten minute warmup period is spent running across the huge grass playing field. The plan says to bring HR up into zone 2, but I like to keep ramping up gradually so that I am at or close to zone 3 for the start of the interval set.
I do the six repeats running in a large oval or sometimes a meandering path on the grass. The outfield of the big baseball field is always good as it is well maintained; just don't step on the dirt. At my age, the recovery interval, ninety seconds in zone 1, is best done walking. The idea is to bring the HR down and give the legs a good rest before the next hard effort.
Wherever I end up on the field when the reps are done I head for the narrow entry point, out onto the sidewalk, and head back up towards the Aloha gas station. Somewhere along the way I get to the last line, five minutes in zone 1, and I continue running at a very easy pace even if my HR stays up a bit in zone 2. If there is time left I divide by two, turn around and run back towards the park, then turn around again until time runs out.
My point is that those five cryptic lines unpack into a while bunch of details that I could not have known the first few times I did it. I know I can vary the repeated section any way I want, because it all happens on the playing field and as long as I include ten minutes on either side I have plenty of time to get there and back. I have a similar arrangement for hill intervals, also on Kilauea but up at the mauka end past Wilson Elementary, where it kicks up between five and ten percent.
I used to have to write this stuff on my arm with a ball point pen until I learned how to program workouts like this into my Garmin FR610. I can do it directly on the watch, or I can do it at the Garmin Connect web site and download the workout to the watch. Here is a video on YouTube that describes the process. I just wish the text display were larger, as my tired old eyes have a hard time seeing some of the detail, especially in the dark like it was this morning.