A popular fitness challenge undertaken by many influencers on YouTube is the month-long practice of doing 100 pushups every day, usually with the goal of building as much upper body strength and muscle as possible in a 30-day window. In a new video on his channel, trainer Jeremy Ethier evaluates just how effective this challenge is.

He cites research which shows that for beginners especially, doing pushups can be just as beneficial in terms of building muscle as the bench press—but that doesn't necessarily mean that churning out high volumes of reps is the way to go.

"In the first week of the challenge, many of you may not even have the strength to reach a total of 100," says Ethier, adding that this is when you will likely feel the most soreness in your chest and arms. However, if you're feeling pain in your back or traps, that's a sign that your technique needs work.

One of the key flaws in these kinds of challenges, Ethier points out, is that you're doing the same exercise every single day without allowing for sufficient recovery. This means that while you are continually breaking down the muscle fibers, you're not giving them enough time at rest in which to grow back stronger. "Our muscles continue to recover and grow up to 48 hours after we work out," he says. "Because of this... you'll likely experience a lot of fatigue in weeks two and three."

Another side effect of this challenge is that it can potentially lead to muscle imbalances, as you are consistently working the same muscle group. "If you regularly train your front muscles without training your back muscles, then the stronger front muscles will over time start to pull your body forward into a hunched over position," says Ethier. "Ideally, to balance this out, you want to perform plenty of back work focused on the muscles that will help keep you upright."

Ultimately, Ethier believes that the 100 pushups challenge causes too many recovery issues for him to consider it a worthwhile endeavor, and he backs this up with research that finds there's a negligible difference in the muscle you'd gain doing this vs. doing a pushup workout twice a week.

"After these 30 days, if your body gets stronger then it's going to need even more of a challenge to continue growing," he says. "Eventually, standard pushups won't be enough, and you'll have to start incorporating bands and added weight... One benefit it does provide, however, is building the habit of exercising. It's a great way of getting your foot in the door and building momentum."