I just joined a gym a few weeks ago and I've noticed that most of the women in the locker room are not wearing underwear underneath their work-out pants. Are there any actual benefits to this, or is it just aesthetic (not wanting panty lines)? I can see how this may be beneficial during spin classes to reduce chafing, but not doing a regular weightlifting circuit.
One internet poll reported that around 33% of women do this. The practice does have at least one benefit in that workout clothing -- especially bike shorts -- is much better at wicking away moisture than many types of women's underwear.
Being a dude my explanation may be wrong but bare with me.
I do a lot of running, cycling and leg workouts. Two things that ruin a workout for me are the workout shorts and underwear. If I'm wearing the wrong pair of underwear or a pair of shorts that are too long then I'm in for a bad experience. That said, most panties have that seam at the bottom of them so imagine cycling or running with that seam against your sensitive area just rubbing against it for the length of the workout. Irritation second to a massive migraine.
Aside from that imagine squats, machine leg presses or any kind of flex work with a pair of undies ready to rip because they stretch only so much. Not fun and I have experienced this as a dude.
Wearing tight stretchy shorts for stretching and squats doesn't leave much to the imagination for everyone in the gym. Panties just add to the ease of view because it is like looking at a dotted cut line (easy to notice even harder to not look at it).
Lastly, I have had the unpleasant luck of having seen in my line of view during a deadlift one of the ladies who thought her baggy shorts hid everything was doing a set of crunches in-front of me. After finishing that rep I had to seek eyewash.
In other words, yes, you can go sans-panties for mere comfort (I've personally seen it) but make sure you got some decent workout shorts on to make up for the clothing that isn't there.
Had a Google but can't find any credible academic work, but there appears to be some academic interest in this field eg.
- Study Examines Breast Movement During Bare-Breasted Running (the article does mention pants)