She included the exercise during a recent after-work gym sesh.

If you thought Jennifer Lopez accepting Alex Rodriguez's marriage proposal mid-leg extensions would be her best gym moment this week, think again. Lopez is back with another look at her workouts, this time showing everyone how leg presses are done.

Lopez posted a video to Instagram, sharing that she fit in a workout while filming her upcoming movie, Marry Me. "Just another Tuesday... After work workout," she captioned the post.

At the start of the video, Lopez's trainer, Dodd Romero, adjusts the weight on the 45-degree leg press machine so that it's loaded with 270 pounds. "I got it," Lopez told her trainer, to which he responded, "Okay, it's heavy." Lopez proceeded to crank out 10 reps and wink at the camera, apparently unfazed.

The exercise that Lopez so smoothly pulled off hits a lot of muscles, so if you steal it for your own workout, plan on knocking it out early on. "Because this exercise works big muscle groups—your glutes, hamstrings, and quads—it should be one of the first lower-body exercises you complete at the gym," Laura Arndt, C.S.C.S., CEO of Matriarc, a pre- and postnatal fitness app, previously told us. The leg press also offers a solid modification to a traditional squat position, as it works many of the same muscles without putting too much strain on your lower back and knees, added Arndt.

Another note: If you have weak glutes and hamstrings and want to engage them more during the exercise, focus on digging into your heels as you press.

BTW, Lopez's trainer's decision to increase her weight probably wasn't just a ploy to impress her Instagram followers. (Although, if it was, it worked.) Continuing to lift heavier and heavier weights can help prevent plateaus when it comes to fat loss, strength, or muscle mass. This practice of lifting heavier over time is one form of progressive overload, the concept of increasing the difficulty of your workouts over time in order to see continued progress.

Heavy leg presses are no joke, especially at the end of a workday. But leave it to the woman who mastered pole dancing in a matter of months and feels like superwoman after hours-long performances to make them look easy.

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