what i have found is side kicks are good for a person who is staying at a constant range and trading with you. its not good if that person is being very agressive and constantly crowding and moving forward and going for take downs etc. i feel that way about kicks in general. you see it even in tae kwon do ,where they will jam eachother and clinch . ive just noticed when one person is putting a lot of effort in crowding you and moving forward ,kicks in general become much less effective.