Six masked males surrounded a woman and stole her motorbike on the Kingsway in Manchester.
The offenders, who were riding three motorbikes, targeted the woman at around 1.05pm in Parrs Wood on Saturday (July 17).
They stole the woman's bag and other possessions, before making off on her motorbike, police said.
The stolen bike was recovered near Taplow Grove, Cheadle Hulme later on Saturday afternoon.
One man, 18 and a boy, 15, have been arrested on suspicion of robbery.
GMP say the 15-year-old received a minor injury prior to arrest and is also in hospital.
An investigation into the robbery is ongoing.
While investigating the robbery, officers spotted a male on a moped in the Smithy Green area of Stockport.
The moped then crashed into a stationary vehicle on Thorn Grove and the 18-year-old rider suffered serious injuries as a result.
GMP have referred the crash to the IOPC.
Superintendent Mark Kenny, of GMP, said: "Investigations are under way by our Serious Collision Investigation Unit to establish the circumstances leading up to the crash. We have also voluntarily referred the matter to the IOPC.
"We also want to speak to anyone who may have witnessed either the robbery or the crash."
Anyone with information should call police on 0161 856 9625 quoting incident 1601 of 17/072021.
Information can also be reported online or by using the Live Chat function at www.gmp.police.uk.
People can also call 101 or Crimestoppers anonymously on 0800 555 111.
