In contrast , Nemtsev et al. ( 20 ) showed take - off velocity signicantly increased .
Contact time signicantly decreased with 3 , 8 , and 12 strides of approach .
In contrast , Nemtsev et al. ( 20 ) showed take - off velocity signicantly increased and contact time signicantly decreased with 3 , 8 , and 12 strides of approach .