As a fitness editor, I'm no stranger to workout challenges, and if you've been with Tom's Guide long enough, you'll notice that I've said yes to most of the weird and wonderful fitness challenges that come up in planning meetings. 100 a day I've tried everything from a week of single-arm cleans and presses to Lily James' 600-abdominal training challenge, but standing dumbbell side bends were on the list this week.

This exercise is often included in standing ab workouts and is sometimes called an oblique bend. To perform dumbbell side bends, first stand with your feet hip distance apart, hold one of the best adjustable dumbbells in one hand and place it against your thigh.

Next, engage your core, bend at the waist, and lower the dumbbell along your leg toward the floor. Then work the abdominal obliques on the side opposite the dumbbells and bring the torso back to the starting position. Repeat as many times as desired before switching sides.

Read on to see what happened when I added this exercise to my abdominal training for a week and why I do not recommend it. A word of caution, what works for me may not work for you or your body. If you are new to exercising or returning to exercising after an injury, I recommend having a personal trainer check your form before adding weight or reps.

Like a fitness guinea pig (if guinea pigs wore lycra), I embarked on this challenge to learn more about this exercise. It was not an exercise I was very familiar with, as it was not one that I incorporated into my abdominal training or strength training sessions. The tutorial said not to be afraid to reach for heavier weights, so I got right to it. The result:

As I mentioned in my previous workout story, I suffer from sciatica after a horseback riding accident as a teenager. When working out my abdominal muscles, I have to be careful to keep my lower back pressed against the floor so as not to strain my spine. For this article, I intended to do 50 reps each side, for a total of 100 reps daily. But after the first day, my lower back was incredibly stiff. The next day I did 25 reps on each side, but to no avail, and I definitely felt tightness and stiffness in my back.

A quick Google search revealed that I was not alone. Personal trainers often do not recommend dumbbell lateral bending because lifting too heavy dumbbells can pull the dumbbells into an excessive range of motion. Furthermore, doing this exercise too often can strain the spine and pinch nerves.

Another reason I abandoned this challenge after two days. I couldn't feel it in my abdominal obliques. I do a lot of Pilates and have done my fair share of abdominal challenges, and when I did 100 deadbugs a day for a week, it hurt when I laughed, but I couldn't really think about my abs during the movement and didn't feel them working. My glutes did, but not my obliques.

After a quick chat with my personal trainer, he told me that if I wanted to work my obliques, there were better exercises that were more gentle on my back and didn't risk injury.

So what should I replace my side bends with? Side planks, parov presses, and bird dogs; read what happened when two Tom's Guide fitness writers did 50 parov presses daily and 50 bird dogs daily for a week.

On the first side plank, seconds after stacking my legs and working my core (read more about how to do side planks with perfect form), I was shaking. I could feel my entire core working to stabilize my body, and I was struggling to hold each side for 40 seconds. To take it to another level, I added a side plank with a boss ball as a finisher for the next strength session.

Lesson learned here. Sometimes exercises just don't work for your body, whether it's because of an old injury, weakness, or tightness. If you feel something is wrong, it is always a good idea to check with your doctor or personal trainer before continuing. Not all pain is DOMs, and if in doubt, stop and switch to easier exercises that you know you can do with perfect form.

Looking for more workout tips? We also show you the results of 50 glute bridges a day for a week, 100 deadbugs a day for a week, and 30 sit-ups a day for 30 days. We've also handpicked the best workout apps to download right now, as well as the best gym bag to take with you.