I was out walking my dogs the other day when a woman jogged past, and I couldn’t help but notice her chest, which happened to be bouncing out of control. Three thoughts immediately ran through my head:

Way to go! I love seeing people putting in work and breaking a sweat. 

Dear God, that looks painful. Does she know what’s happening to those poor ligaments?! 

Huh, having something there to actually bounce must be nice, though…

I’ll spare you the details of the rest of my internal monologue, but the point is that it reminded me of the importance of wearing the right gear — not only to maximize your workouts, but also to minimize any potential nasty side effects, such as said bouncing, chafing, snagging, riding up, falling down, constricting, tripping or worse (injury).

Plus, let’s face it — when you look good, you feel good. And when you feel good, you can give it all you’ve got, whether you’re hitting the gym, running the trails or competing at an event.

Here are my nine no-no’s when it comes to suiting up for that next sweat session:

1. Unsupportive Sports Bras (or Shorts)

Ladies, did you know that you can do permanent damage to connective tissue over time if you neglect to give your breasts the correct support? And, gentlemen, you’re not immune to the jostling of certain body parts either. So, regardless of gender, do yourself a favor and find something that provides plenty of reinforcement for high-impact activities.

2. 100 Percent Cotton Clothing

It might be the fabric of our lives, but it’s the foe of comfortable workouts. Cotton is wonderfully absorbent, but that’s also it’s downfall; damp, slow-drying shirts tend to bring on chills and irritate skin. Instead, opt for synthetics and moisture-wicking fabrics, which are quick-drying, lightweight and designed for efficient evaporation.

3. Baggy Layers

Tempted to tent that not-quite-beach-ready body in loose-fitting clothing? Little do you know, you’re creating a potential safety hazard. Not only does extra material up your chances of getting snagged on equipment, but it also prevents you from checking form and alignment. Exchange oversized apparel for more form-fitting gear, which doubles as extra incentive to get to the gym!

4. Overly-Constrictive Pieces

Too loose isn’t good, but too tight isn’t any better. Any outfit you have to pour yourself into will only hamper movement, threaten circulation and probably make you feel pretty self-conscious. Instead, find a happy medium with fabrics and cuts that skim your figure and allow for a full range of motion.

5. Past-Their-Prime Shoes 

You maybe tempted to squeeze a few more miles into fraying footwear, but it’s better to ditch your kicks before you put yourself at risk for injury. Worn-out treads and flattened arch support won’t serve you well in the long run — and could actually do some damage during long runs. Replace your sneakers every 500 miles or so, and consider a gait analysis to find the best model for you.

6. Too Much Bling

I may sound old-school, and it’s probably because this was drilled into me early in my high school track & field years, but the only metal objects you should be swinging around at the gym are kettlebells. This will allow you to concentrate on the task at hand, rather than keeping your necklace or earrings from getting caught or damaged.

Rings, especially, should be kept at home or stowed away. You only have to hear one horror story about an engagement bauble getting stolen after being left behind in a gym shower to set you straight on this one. True story.

7. Eau de Poo Poo

An inside joke in my family, this is the nickname we give to stinky perfumes. Whether you’re squeezed into the close quarters of spin class, taking a dip in your gym’s pool or lined up mat-to-mat in yoga, please forgo strong scents. Body heat and sweat only intensify the issue, and the last thing you want is to ruin your classmate’s workout by giving them a stomach-turning headache.

8. Untested Apparel 

You snag a deal on some gear, and then later realize why it was deeply discounted — because it sucks. Yep, been there, done that. It was mid-bootcamp, in fact, when a friend gave me a heads up on my too-thin tights (oops). So take it from me: Use the ‘try before you buy’ rule by jumping around and bending over in the dressing room in order to avoid anything see-through, low-cut or otherwise offensive.

9. Almost Anything Gray

Unless you’re prepared to own some pretty awkwardly-placed post-workout sweat stains, avoid the color gray for super-intense exercise. I learned this the hard way while marathon training in one of my favorite styles of (gray) capris last fall. I still love ’em, but now I just use that pair for less sweaty endeavors, such as restorative yoga, hiking and Pilates classes.

Are there any off-limits outfits you’d add to the list?