What types of exercises are recommended for rehabilitating from chondromalacia patella?

Quad balance strengt. Knee cap problems are frequently related to imbalance of the quads with "overdeveloped" lateral quads and "underdeveloped" medial quads.
Core . Chondromalacia patella (runners knee) is due to overload of the patellofemoral joint (knee cap against the end of the thigh bone). Running causes high forces in this portion of the joint. So does arising from a chair, going up/down stairs. Treatment consists of activity modification, ice, anti-inflammatory meds and therapy aimed at flexibility and strengthening, especially of your core.