premise: A group of girls are standing with rollerblades on while a man is lifting his leg next to them. hypothesis: the girls are weightlifters.
contradiction: Girls are standing with rollerblades in sentence 1; although they could be weight lifters they are not actively performing the action of weight lifting. The contradiction is the girls are standing in rollerblades while man is the one lifting and although girls could be weight lifters they are not actively doing so.