I always look forward to Tuesday nights. They mean speedwork in Central Park, usually a tempo or some other crazy long(ish) workout. Occasionally, though, we do hill repeats. Hill repeats are great because they're strength training in disguise but hill repeats also suck because, well, they're strength training in disguise.
These short, tough repeats are great because they work your core, your hip flexors, abductors, adductors, lower back, and hamstrings. They also help you to activate your fast-twitch muscles, something a tempo run doesn't do. I'm going out of town this weekend so I'll be missing the track meet but I have my first road mile of the summer next week so I figure the short speedwork will help with that too.
I might as well enjoy these short bursts of speed now because soon it will be marathon training season with its longer intervals and heavy dose of tempo runs.
*Quick plug: if you're in town you should come out to the Whippet's track meet. It's only $10 and should be really fun! Details are here: Dashing Whippets Track Meet