Hill Repeats

Today's workout was 2.6 miles easy warm up.  Then I did 6 hill repeats.  This was .25 miles up hill then a 1 minutes rest and .25 mile down.  Finally I finished with 2.4 miles easy warm down.  This was a total of 8 miles.  Hill repeats are hard.  The uphill part is hard.  The down hill part is easy.  This is supposed to make me stronger.