Not every training session should be a heavy lifting day! For those times when your body is feeling a bit worn down from intense training, it's still possible to get a productive workout in by doing a shorter, less intense workout that focuses on building up your weaknesses, improving mobility deficits, and working on your conditioning.
The following video is a workout I did in NYC's Highbridge Park, using exclusively body weight movements, mobility drills, and some stair sprints for conditioning.