If you don't know your way around a weight room, heading to the gym can be intimidating -- and even dangerous. But paying attention to a few simple rules of proper technique can make you slimmer, stronger and healthier all over.
We spent an afternoon at Equinox with trainer and manager Rebecca Woll, learning the ins and outs of some of the most popular strength-training machines.
In the coming weeks, we'll be sharing Woll's thoughts on the biggest mistakes we all make while building muscle, plus her tips and tricks for better form. This week, we're perfecting the reverse fly, a move performed on the same machine used in last week's seated fly.
The Faux Pas: One of the most dangerous mistakes made in this position is taking the arms past 90 degrees, says Woll. Also, too often there's an arch in the lower back or a curve to the shoulders that will decrease the effectiveness of the move and can lead to injury. A workout buddy can help you align your spine, as Woll demonstrates below.
The Fix: Luckily, most people aren't naturally flexible enough to extend the arms too far in this position, but be aware of how far back you push yours, says Woll. Make sure the toes and heels are firmly on the ground, she advises, and push through the whole foot as you lean your chest against the bench. Keep the back flat -- you'll know you're doing it right when you feel your abs engage. 
Tell us how it goes in the comments below, and be sure to check back over the following weeks to fix your form on the row machine, the shoulder press and more.
Check out more in our Fix Your Form series below:
Fix Your Form
Photos by Damon Dahlen, AOL
For more on fitness and exercise, click here.