Perfect Form: How to Know If You're Working Your Butt or Your Thighs

Ever feel like your squats are bulking up legs rather than slimming than down? Well, it’s not that uncommon. Your form is probably to blame. We chatted with Nikki Warren, co-founder of Kaia FIT, who set us straight.

First, a little squat/anatomy lesson. “Hamstrings are the literal backbone to our squats,” Warren says. “They are the antagonist muscle, providing control and support to the prime mover (quads). When we’re doing squats, it’s easy to focus on the front line of the body and activate those muscles that we can easily see and touch.” But to get that lifted bum and those lean thighs, you need to focus on the backs of your legs.

Next, a quick refresher in squat form.

  • Keep your gaze above the shoulder line, which will force your chest to stay up and open.
  • Sink the weight back into your heels, enough so that you can wiggle all 10 toes.
  • Knees back behind your 10 wiggling toes.
  • Once you’ve reached the depth of your squat (buttocks parallel with your knees), pause and get ready to activate your hamstrings.

Finally—and this is the key—here’s you how you know you’re activate your hamstrings:

  • Mentally focus on the backline on your body (hamstrings, glutes, erector spinae), visualize those firing up.
  • Tuck your pelvis under by activating your glutes and pulling them toward each other, you should feel the back line of your legs light up (similar to the upward pull on a bike).
  • Keeping that glute activation, press through your heels to stand up.

Once you’ve nailed that, then you can start adding weight. Stick five-pound weights ($11) and then increase to 8 or 10 pounds.

Have you been using your quads or hamstrings? Try this technique and let us know if you feel the difference!