As you know by now, inefficient equipment can lead to great workouts. It’s why we prefer free weights to machines, and it’s why kettlebells, slosh tubes, and sandbags have gotten so much attention from us recently. The more work the equipment does for you, whether it’s a bench press machine keeping your press perfectly aligned or even a symmetrical dumbbell with perfect balance, the less work you’re actually performing. And a workout’s effectiveness depends exactly on that: the amount of work performed. Using symmetrical free weights like a barbell or a dumbbell is great and allows you to focus purely on moving tons of weight (a form of work); using machines that guide and assist you is actually counterproductive (don’t be a slacker) and ineffective.