Thieves took items, including a heart monitor and laptop, from a vehicle parked on a housing estate in Deer Park Road, Langtoft.
A pair of white, blue and red Alpinestars Tech 10 Motocross boots, a blue, orange and yellow Fox motorcycle helmet, Toshiba grey laptop and hand-held heart monitor were stolen between 6.30pm on Tuesday and 9.30am on Wednesday.
Anyone with information should call 101 or Crimestoppers, anonymously, on 0800 555 111.