The Cross Country exercise works your shoulders, arms, butt, quads, inner thighs, outer thighs and calves.
Using the same leg throughout, step out into a side lunge, keeping your arms at shoulder height. As you return to standing, extend your arms overhead. And lunge forward, return to standing and extend your arms overhead. And lunge backward, return to standing and extend your arms overhead. Do the side-front-back lunge combo eight times, then switch legs and repeat. Do two sets total.