On January 6, 2007, about 1330 eastern standard time, a Schweizer SGS 2-33 glider, N5728S, registered to and operated by High Soaring, Inc., was landed hard following failure of the weak link during a tow from the Immokalee Airport, Immokalee, Florida. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 91 instructional flight from Immokalee Airport. The glider was not damaged and the certified flight instructor (CFI) sustained serious injuries but the pilot-rated student was not injured. The flight was originating at the time of the accident. The CFI stated that the pilot-rated student was at the controls during an auto tow, and while at 40 feet and 43 knots indicated airspeed while increasing pitch, the "weak link" at the automotive end broke. The pilot-rated student responded immediately by pitching down per their previous briefing. Landing attitude was established approximately 5 feet above the ground, but the glider made a hard landing onto grass on airport property. The CFI notified the NTSB of the accident on January 16, 2007, which was after her release from the hospital on January 11, 2007. The failed weak link was discarded by the operator before the NTSB made contact.