Resisted hamstring strengthening exercises (ex. hamstring curls) are generally avoided in the early phase of rehabilitation following PCL reconstruction - this is because the hamstrings create a posterior pull on the tibia which increases stress on the graft.
Kaufman et al studied the joint reactive forces during isokinetic exercises. They found that posterior shear forces exist during the flexion portion of isokinetic exercise and during extension exercises at knee joint angles greater than 40 degrees. The maximum posterior shear force was 1.7 body weight.
1. & 2. Progressively obtaining a full range of motion is an initial goal of rehabilitation. Quadriceps muscles help to obtain extension and near terminal extension actually decrease force on the graft. Non-weight-bearing resisted knee extension (60° to 0°) is an acceptable exercise in the initial stages following PCL reconstruction.
3. Prone positioning allows the weight of the leg to help maintain an anterior force on the tibia, while passive flexion minimizes hamstring pull.
5. Active ankle exercises such as ankle pumps are encouraged.
Paine R. Section A: Language of exercise and rehabilitation. In: DeLee JC, Drez D, Miller MD, eds. Rehabilitation and Therapeutic Modalities: Orthopaedic Sports Medicine. Vol 2. 3rd ed. Philadelphia, PA: Saunders-Elsevier; 2010:221-237.
Kaufman KR, An KN, Litchy WJ, Morrey BF, Chao EY. Dynamic joint forces during knee isokinetic exercise. Am J Sports Med. 1991 May-Jun;19(3):305-16.
PMID:1867339 (Link to Abstract)