On February 18, 2017, about 1529 mountain standard time, a Piper PA28R-200 airplane, N2702R, sustained substantial damage after it impacted terrain shortly after takeoff from the Centennial Airport (APA), Centennial, Colorado. The flight instructor sustained minor injuries, and the private pilot receiving instruction sustained serious injuries. The airplane was registered to a private individual and operated by Centennial Flyers of Englewood, Colorado, and the instructional flight was being conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and a flight plan was not filed. According to the private pilot who was seated in the left seat, the flight instructor tried to prime the engine several times while pushing the mixture back and forth several times. After the third try, the engine started, and the private pilot proceeded to prepare for takeoff on runway 17L. He stated that the airplane had difficulty obtained lift during takeoff roll. After liftoff about 75 knots, the engine RPMs remained high and power seemed sufficient, but the airplane was not gaining altitude. Toward the end of the runway, the flight instructor took over the controls and flew the aircraft past the departure end of the 10,000-ft runway, crossed over highway E-470, banked left, and then touched down in grassy area. The private pilot recalled that the airspeed was about 55 knots prior to bracing for impact with trees. He stated that the flight instructor passed out upon impact with a tree and recalled feeling that the left wing sheared off. He recalled pulling himself out of the aircraft and being transported to the hospital. According to the flight instructor, the engine was run up to 2,000 RPMs, with positive magneto and flight control checks prior to departure. The fuel pump was ON and the mixture was leaned for takeoff. The rotation speed was about 65 knots within about a 1,000-ft ground roll. The airplane gained airspeed to about 75 to 80 knots and had a slow climb. The flight instructor verified that the flap handle was down and the flaps were visually up. Upon reaching about 150 ft altitude, he felt like something was pushing the airplane down. He stated that the engine seemed to have full RPMs and the throttle and mixture were full forward. He stated that he recalled seeing the airspeed at 65 knots and heard a stall warning horn when the airplane contacted the ground. In an interview after the accident, the private pilot stated that a Falcon Jet took off on runway 17L, about 2 minutes prior to takeoff, and he was concerned about wake turbulence. The flight instructor stated that he was not concerned about the possible wake turbulence because of the wind conditions at takeoff. The flight instructor reported that he thought that the airplane's climbout was affected by a wind shear. The accident site revealed that aircraft landed in grassy area heading approximately 120°, about 1 mile west of APA. Landing gear track marks showed all three landing gear on the ground with a straight track until impact with a tree. After impact with the tree, the airplane crossed a parking lot driveway, skidded 100 ft, and came to rest inverted. The airplane wreckage was transported to a secure facility to be examined. During the examination, the throttle, propeller, and mixture controls functioned normally. The engine rotated freely and all cylinders produced compression. The magnetos produced spark at all spark plug terminals. The engine oil screen was found clean. After the visual inspection, the engine was successfully run on the airframe throughout its operating range. The elevator, aileron, and rudder cables were found intact and functional except for impact related damage.