track workouts?

Looking at your logs I might suggest that you might benefit from upping your mileage rather than speedwork at the track.

For me at least, doing higher mileage offered much more benefits than speedwork and was my primary focus over the past year. The idea is that improvements in running economy are a cheap and easy.

Faster running is not the only benefit of improved running economy. I became much less injury prone and my recovery time (From hard training as well as races) improved quite a bit.

Just be sure to follow the rules when ramping up the mileage:

1). Don't increase by more than 10%
2). Follow the Hard/Easy Principle
3). Schedule Regular Cutback Weeks
4). Listen to your body and get plenty of Rest

Good luck