A CRJ-900LR was conducting Air Canada Flight 8485 from Edmonton Intl. (CYEG), AB to Vancouver Intl. (CYVR), BC with 4 crew members and 58 passengers on board. The Captain was conducting a check ride and was the pilot monitoring. The First Officer was the pilot flying. The landing at CYVR was recorded as being 2.789g resulting in the requirement for a high load landing event inspection. The flight crew taxied to the gate and were unable to start the airplane?s auxiliary power unit. After shutting down the aircraft, the flight crew realized that a flight attendant (FA) was injured; paramedics were called to attend. The FA, who was seated in the aft jump seat during the landing, was seriously injured and, after first aid was administered, was taken to a local hospital. The other cabin crew member received minor injuries. Company Maintenance conducted an inspection and found that both main landing gear shocks showed evidence of having bottomed out. They then initiated a high load landing event (HLLE) inspection. The airplane remained on the ground at CYVR for 6 days while the HLLE inspection and related tasks were carried out. The subsequent maintenance included replacing both of the main landing gear. The airplane has been returned to service.