Abdominal exercises, like it or not, are essential to building and maintaining a strong, healthy physique. While aiming for a bench press PR may be a great incentive to hit the gym, it is the stabilizing and supporting muscles of the trunk (rectus abdominis, transverse abdominis, internal and external obliques) that allow us to lift heavier objects, run faster, and jump higher.

However, core training can get a little, well, boring. For Pilates and yoga enthusiasts, it is relatively easy to train the abdominal muscles in new and interesting ways. But for those who like to run, take HIIT classes, or hold barbells, getting down on the mat can be a challenge.

Thanks to a genetic back problem that has plagued me (literally) for years. Fortunately, I have been able to increase my running mileage and increase my squat weight without being hampered by back pain.

As a result of all this abdominal training, my core is clearly stronger, but now doing sit-ups every day doesn't work my abs as well as it used to (and, as you can imagine, is boring me to tears). So I decided to take my core training to another level by doing weighted sit-ups every day for a week. If you are new to exercising, start with basic movements (such as modified planks or standard crunches) before moving on to these.

This exercise requires some type of weight. These can be medicine balls, adjustable dumbbells, kettlebells, or weight plates. Make sure you have proper form for weighted sit-ups:

Even though it is a classic exercise, you need a relatively strong core to perform sit-ups properly on their own, even without extra weights. To get the correct form, try practicing a standard sit-up first. If you need further improvement, ask a friend to support your legs while you do them a few times. You may also start with crunches before sit-ups. Here's how to do sit-ups with perfect form and why it's so important.

Wanting to add something new to my usual core training, I did weighted sit-ups every day for a week, using a 15-pound kettlebell and aiming for three sets of 10 repetitions. The result was this:

Admittedly, I didn't think that adding weighted sit-ups to my workout would result in any noticeable fatigue. However, I was quite wrong. By the end of the third set on the first day, my abs were waving the white flag. I barely made it to the last rep with good form.

As expected, I was incredibly sore the next day. In fact, I had to replace my 15-pound kettlebell with a 10-pound plate and reduce my sets of three 10 repetitions to one set of 10. Even that was painful.

After the shock of the first two days passed, I was able to return to the 15-pound kettlebells. However, once I got a little more comfortable with the movements, I found it very easy to let the momentum take over and not fully contract my core muscles.

This is an easy fix to fall back on, especially when fatigue sets in. But by slowing down and stopping completely at the end of a repetition, I was able to reset and refocus on using the right muscles for the job.

By mid-week, I began to really feel the benefits. My usual planks and birddogs felt like a total breeze. Bicycle crunches felt as easy as riding a real bike. Even weighted situps began to feel just a little more difficult.

I considered using heavier weights for the rest of the days, but decided against it. Instead, I switched from 15-pound kettlebells to 15-pound dumbbells to keep things interesting.

To my surprise, a week's worth of weighted situps made my usual lower body routine feel more like a warm-up than a work set. The goblet squats, which were always a problem for me, were easy. I added a pound and was able to do another set.

[3] I attribute much of this success to the fact that I was able to stabilize my abs. Goblet squats always feel a little unstable due to my lower back issues, but after a week of heavy core training, my entire posterior chain felt much more solid.

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