Light, medium or high: match the support to your workout

The support level is the first thing to check, and most names here state it. More movement needs more support.

• Light support: for yoga, pilates, barre or all-day wear. adidas says its Hyperglam Rib Bralette gives light support for barre or pilates, and Nike puts the Indy Light-Support bra on low-impact workouts.
• Medium support: most of this range. Nike says the Swoosh Medium Support bra suits training workouts and dance classes, and Under Armour lists cycling, weight training and boxing as medium-support activities.
• High support: for running and jumping. Nike says the Indy High-Support bra keeps motion to a minimum, which makes it a pick for runs. Under Armour and adidas also have high-support bras here.

Some sizes include your cup range

Many sports bras come in plain sizes from XS to XL. Some add the cup range to the size, and that helps a lot. On adidas Powerreact and Powerimpact bras, S AB means size small for A and B cups, and S CD means size small for C and D cups. Under Armour Infinity bras use S A-C, and some come in D-DD too. If you have a smaller chest, look for the AB or A-C sizes. adidas also makes a plus-size version of its Aeroreact light-support bra.

Straps and backs: what the names mean

Adjustable straps, as on the Nike Indy Adjustable bras, let you set the fit yourself. The Nike Pro Indy Plunge has convertible straps you can wear in more than one way. Crossback styles, like the Under Armour Crossback Mid, cross the straps behind you. The SQUATWOLF Serpent opens with a zip at the front.

If you are buying your first sports bra, start with a medium-support padded bra such as the Nike Swoosh Medium Support. Add a high-support bra when you start running, and see women's running gear for the rest of your kit.