Modification of quadriceps femoris muscle exercises during knee rehabilitation.

Rehabilitation of the quadriceps femoris muscle is the cornerstone of full recovery after inactivity, immobilization, or surgery of the knee. Muscle strengthening programs often are interrupted by patients' complaints of pain experienced during exercise, which frequently prolong the patients' convalescence period. Specific modifications of standard quadriceps femoris muscle exercises often allow completely pain-free exercise, thus providing a faster progression of treatment and a subsequently shorter rehabilitation period. The purposes of this article are to review briefly patellofemoral biomechanics as it relates to quadriceps muscle rehabilitation and to summarize several modifications that in our clinical experience repeatedly have reduced pain during exercise.