"Tabata swim WOD"

A friend of mine is in town and I therefore have a training partner for this week. Yesterday evening I took him to the treadmill and made him do the CrossFit Endurance Tabata run. For anyone who hasn't tried it, I can highly recommend it. It's an mindblowing experience! You simple set the treadmill to a 12% incline and then work your way through eight sets of 20 sec. on /10 sec. off. All out effort! Amazing how hard four minutes of work can be. I didn't let him suffer on his own though and went through it myself as well. Kept an 17km/h pace on the first five sets but had to take it down to 16,5 on the last three. The heavy squats from the morning were showing their effect. Last time i did it, i felt sick for an hour afterwards and even had to go and puke three times. Awesome!
Anyway, we decided to meet up again this evening to do some swimming. A perfect opportunity to test my newest "water-WOD" on someone else than myself. I continued to follow the "tabata pathway" and decided we should do four exercises. Here goes:

"Tabata swim WOD"
Butterfly kicks (with board)
Muscle ups on the ledge
Submerged breath holds
Sculling (arms below shoulders)

Doing a tabata workout in the pool was a new and interesting experience. The butterfly kicks were hard on the abs and it was difficult breathing because of the up and downward movement. Muscle ups proved difficult in the last three sets, because of muscular exhaustion. The interesting part were the submerged breath holds. They got easier and easier as we went through them. That is something i have experienced before, when doing multiple long dives. There is probably a scientific explanation for it, but I don't know it. The sculling on the other hand was WAY harder than i had anticipated. After two sets my arms were toast and i had a hard time going on for 20 seconds. All in all i think it was a good workout, but i could probably have put one or two extra exercises in it to make it more demanding.
The easiest way to make this workout work, is to bring a friend to keep track of time. I was pretty accurate counting twenty seconds in my head while I was submerged, but not thinking about time while you are under water probably makes it a little easier. I think sculling is the hardest at shoulder hight, were the resistance of the water against the arms is greatest. But feel free to change the position.

Enjoy!
/Kasper