4

Stand, with a tiny knee bend and two dumbbells in hands, palms in. Hinge forward at the hips so your arms hang. Bend elbows to pull weights up to ribs, drawing shoulder blades back and down. Return to start. That’s one rep. Do 10 reps and repeat for three sets.

It works the hamstrings, the hips, the entire back and the core, all to improve stability on the run.