1. Catch panels
The fabric on your suit’s forearm will often have a texture designed to help you ‘catch’ the water and get more speed per stroke. Besides helping you ‘feel’ the water, thinner materials on the sleeves also make them more flexible and easier to remove.
2. Chest panel
Many top-end suits have a panel of thinner, more flexible neoprene in the chest. This panel enables the suit to stretch more easily helping you reach further with every stroke and allowing you to get as much air as possible into your lungs.
Freedom of movement around the shoulders is vital in a wetsuit so you can turn your arms over quickly and easily. You need as much of your ‘normal’ movement range as possible so many wetsuits build in more flexible material around the shoulders to help.
Saving your legs for the bike and run ahead is key for triathletes of all levels. If your lower body tends to sink in the water then a wetsuit with thicker (up to 5mm is race-legal), more buoyant neoprene in the legs can help you hold your legs higher and facilitate your kick.