As a trainer [1], one of the things that makes me the happiest is seeing people taking care of their bodies and being healthy. With that being said, there are a few exercises that do more harm than good. In order to prevent injury, consider eliminating these moves from your exercise repertoire.
Crunches
Crunches are one of the most universal exercises when it comes to training your core, but they actually aren't that effective. Stuart McGill, PhD, world renowned professor of biomechanics, found that crunches can put up to 340 kilograms of compressive force on the spine when bent in flexion. If you currently have back pain [3], this is an exercise to avoid at all costs. Instead of doing crunches, try any of these 37 crunch-free exercises to strengthen your core [4].
Standing Oblique Side Bend
While this exercise does strengthen and build muscle in the obliques, it does so at a cost. Similar to the crunch, this movement places extra stress on the spine, which can lead to a plethora of injuries like a disc bulge. Instead try a unilateral kettlebell carry (holding a kettlebell in one hand with the arm extended). This move will strengthen your quadratus lumborum, your abdominal wall, obliques, back, and shoulders. It's extremely effective because it requires you to create tension in your muscles in order to maintain an upright position.
Barbell Deadlifts (If You're a Beginner)
Recently deadlifts [5] have become one of the most popular full-body exercises in the gym. Deadlifts are great way to strengthen your posterior chain and build strength and power. If you don't have much experience strength training, doing barbell deadlifts with flawed movements can put you at risk for injury. Start by mastering the dumbbell deadlift [6] before advancing to the barbell deadlift. Once you've got that down, have an experienced strength coach to teach you how to do a barbell deadlift.