Three youths assaulted a teenager as he walked home across fields in Ilkeston.
The victim, 15, was walking over fields from St John Houghton Community School towards Kirk Hallam Community School when the robbery took place.
The offenders appeared from behind bushes and one of them punched the victim, who fell to the ground.
They then stole a pair of Diadora trainers from his bag and fled. The robbery happened at 3.20pm on Friday, November 7.
One of the robbers was white, aged about 17, 6ft 1ins, of skinny build, with curly, dark brown hair and large ears. He was wearing a black Adidas coat with white stripes on the chest, and black Adidas jogging bottoms.
The second was white, aged about 17, 5ft 11ins, of medium build. He was wearing a black coat with a hood, and dark blue Adidas jogging bottoms with red stripes.
The third was white, aged about 17, of medium build and wearing black clothing.