http://AskTheTrainer.com/best-chest-exercises.html Personal Trainer Michael Behnken, MS, NASM-CPT-PES, CSCS Iso lateral simply means one side at a time. This is a great exercise for developing functional strength in your chest, anterior deltoids and triceps. If you are able to use a heavy weight your core will need to be strong. This is a great way to determine if one side of your chest is stronger than the other. If one side of your chest is a lot stronger than the other, you may have muscle imbalances which you need to correct before you can increase your bench press or build your chest to its full potential. http://AskTheTrainer.com/posture-problems.html