obstacle race 
noun
A race in which various obstacles, such as fences, pits, and climbing nets, have to be negotiated.Organise simple races between the children, for example weaving in and out of trees along a certain length of the park, a hopping race, a three-legged race or an obstacle race....
- Events included an egg and spoon race, a sack race, an obstacle race and a javelin throw.
- The competition was divided into two teams, Blue and Green, with 12 competition types, including aerobics, a bag relay race, an obstacle race, and a horse ride.
- peripheral nervous system
- in the middle of
- in the name of
- in the nature of
- in the nature of things
- in the neighbourhood of
- in the nick of time
- in the nip
- in the nude
- in the offing
- in the ordinary way
- in the (or in no) mood for/to do something
- in the (or one's) road
- in the (or one's) way
- in theory
- in the pay of
- in the person of
- in the picture
- in the pink
- in the pipeline
- in the poo
- in the power of
- in the process
- in the pudding club
- in the raw