Constant Aquathlon

The last Friday of the summer months, we offer an Aquathlon workout.
This week we did two sets:

10 minute choice swim warm up
3 x [400 swim
     2/3 mile run on grass fields
     (descend total time 1-3)]
3 x [200 swim
     1/3 mile run on grass
     (descend total time 1-3]
200 easy swim cool down