You'll probably work up a sweat in a sports bra and you don't want that sweat to get trapped against your skin because it causes friction which rubs and irritates the skin. Wicking material is usually made up of multiple layers that pulls moisture away from the skin towards the outer layer where it can evaporate. Working out in a bra that doesn't have wicking material can cause you to get sores under your breasts and at the armpits and this leaves you open to infection so DON'T DO IT!
Compression or Encapsulation
These words refer to the cups on a sports bra. Compression cups aren't sized like regular bras (e.g. 32FF, 34G, 36GG etc). Instead they have sizes like small, medium, large. The cups support by keeping the breast tissue compressed close to the chest, thus minimizing bounce. This works well for high impact sports. If you prefer your breasts to be separated then you need an encapsulation style sports bra which houses each breast in a separate cup.
|Enell is a compression bra that supports by keeping the breasts close to the chest.|
While your band is still the most critical part of your support in a sports bra (if your band is too big for you in any bra then it can't support you enough and the pressure rests on your straps) you also want wider straps to disperse the impact of vertical movements like jumping and running.
When you're working out you have a greater range of arm movements. If your cups come up too high towards your armpits the fabric can rub against you and chafe the skin. Lots of sports bras now have tapered armpits so that the edge of the cup doesn't rub. Panache Sports Bra is particularly good for this because they have also adjusted the position of the straps so that they don't slip on narrow or sloping shoulders.
|The tapered armpit on Panache Sports Bra means you can move your arms through full rotation without chafing|
Some sports bras have a J hook on the straps at the back so that you can create a racerback shape. This is a cross shape that reduces the movement of the bra even more.
|Both Panache Sports Bra and Cake's Orange Zest Sports Bra have racerback options|