Always, always, always wear the proper footwear. This is particularly poignant for plus-sizes, because the right support on your feet can determine how your lower body will react to exercise or sports activities.
Many major brands make choosing the right footwear easy for you because athletic shoes are marketed by activity. For example, Nike remains the premier choice for runners. Reebok makes a Sweet Surf Mesh model that is great for aerobics activity. The Adidas Lyte Speed GCS shoe is perfect for basketball players as it has been designed for quick directional changes.
Many plus-size women look for shoes in wide widths. Similar to clothing, retailers might not carry wide widths, but the manufacturer could make those large, wider styles. It's worth your time to go online or call to find out. It's important to your exercise or sports regimen to have the right support on your feet!