Running tip #77 … out rest back rest out rest rest rest … (hear the rhythm?)
I’d forgotten about a favorite workout until I did it this morning with seejanerun, my running club of moms. Here we are lining up for The Owl’s Roost Rumble, a trail 1/2 marathon we all ran several years ago:
In preparation for an April goal race, we are at the point in our training where we can enjoy what I call a big meal of intervals. Up until now, we’ve been building our appetite (so to speak) with shorter, easier, “pleasantly fatiguing” workout/snacks … so today’s meal satisfied that deep hunger runner’s get when closing in on a goal race.
Warm up 15 minutes, then change into whatever racing shoes you plan to wear in goal race.
On a stretch of trail that can accommodate 2-3 people abreast, run hard for exactly 100 seconds and mark your end-point with a big stick or a tossed tee-shirt. Regroup and recover and for 75 seconds. Then, turn back to re-trace your steps for another 100-second fast interval, making it to or beyond the original starting point. Recover, again, for 75 seconds before setting off on the 3rd of three 100-second intervals in a set.
Between sets, jog back to the very beginning and wait until your heart rate is back under 100 before set #2 … usually it takes about 3-4 minutes. 
Advanced runners do 3 sets of 3 for 9 total intervals.
Us old gals get full after 2 sets.
Save room for dessert and cool down for 15 minutes!