Heavy Leg Workouts

Is it the summer? Lack of motivation? For whatever the reason, most of my recent workouts and runs have felt heavy legged. I haven't had the motivation to kick it into my highest gear in the last 30 meters of intervals or just to raise my heartrate too high. Just going through the motions of workouts. Be that as it may, I'm still getting my mileage. Here are my last two workouts:

Tuesday Central Park hill fartleks

Wednesday easy miles

Current training calendar