Those weight machines at the gym may look impressive, but they aren’t helping you build an impressive physique. You’ll burn more calories and work more muscles at once by doing a side lunge instead of using an isolation equipment piece like the adductor machine. “During a side lunge there is a lot of balance and stability required, thus meaning more work by the adductors (or inner thigh muscles). In addition to strengthening the ligaments of the knee, all the other muscles in the legs are being worked as well— quads, glutes, hamstrings and calves. The more muscles being worked, the more energy being burned, which means leaner, stronger legs faster,” says Dominic Lucibello, a certified strength and conditioning specialist and owner of Breakthrough Fitness in Orlando, Florida.