When doing upper body strength exercises for triathlon, you must first think of what movements are essential. If you take the swim, then 3 muscle groups that are important to have strength and power are the latissimus dorsi (back), Bicerps (arm) and the Pectoral Major (chest) muscle groups. Here are some exercises to strengthen these muscles:
1. Latissimus dorsi (back): pull ups and ball cobras. Pull ups are a great overall back strengthing exercise; remember to lower your body down til your arms are nearly fully extended (in the water after the entry you must be able to fully extend your arm as you catch the water). For the Ball Cobra, make sure to draw in your navel and keep your glutes tight. Raise your body off the ball until your body is at a 45 degree angle perpendicular to the ground. Keep the head in neutral. Do 3 sets of each exercise for a rep count of 12-15 per set.
2. Bicep (arm): straight arm bicep curl. Choose a weight that you can comfortably complete a set of 12-15 reps. Keep your elbows close to your body. Do not move your back--keep it erect. Fully extend your arms at the bottom of each rep. Do 3 sets of each exercise for a rep count of 12-15 per set.
3. Pectoral Major (chest): push up. This is a classic exercise that always works. Three sets of 15 reps should keep the chest strong and in triathlon shape for swim, run and bike. This also is great for the core.