HI Clay, welcome to the wondering/confusing world of swimming. I was a competitive swimmer for 15 years, and now I'm sticking with triathlons!

To help clarify the swimming lingo....first you need to make sure the workout you are referring to is yrds or meters. Based on the times you provided, it is yards, unless you are an Olympian I don't know about, lol!

So, the first set consists of 8 x(times) 25 yrds. So you are swimming 8 seperate lengths(1 length of the pool=25 yrds) 25 yrds at a time. So you will stop at each end of the pool. This set also totals 200 yrds. (4 lengths =100 yrds so 8 lengths =200 yrds). So the timing comes in that you need to do each 25 within 50 seconds. This set gives you ample time to rest. Now if that seems like a lot of time for you, maybe you can drill that 25, or swim odd stroke, or even swim it at a fast pace. Just because the workout you are referring to doesn't specify to drill, or pace it, doesn't mean you can't do whatever you need to accomplish your workout! Spice things up!

The next set 4 x 100 yrds (4 seperate 100 yrds (remember 100 yrds is 4 lengths)) Now, you are to do 4 lengths without stopping on the 1:15 interval....now this is a difficult set, you need to be holding a very fast pace, and you will not get a lot of rest, so the set is suppose to be hard. This is a good training set and will elevate your rate heart very quickly.

Hope this helps, and I made some sense, it is very hard trying to de-code swimming through writing it out! Have fun!!