Effect of Two Strengthening Protocols for Lower Limbs in Patients With Patellofemoral Pain

Patellofemoral Pain (PFP) is one of the most common disorders that affecting the physically active population, and its incidence is higher among women. Despite the high incidence, the etiologies of this painful syndrome are still unclear. Research has verified the influence of hip stabilizers on knee injurie and has demonstrated a deficit of strength of the hip lateral rotator, abductors and extensors muscles in patients with PFP. The aim of this study is to compare the effectiveness of strengthening the Posterolateral Hip Complex with the Anteromedial Hip Complex associated with quadriceps strengthening for pain reduction and improvement of functional capacity in patients with PFP.

The physical therapy sessions will average duration of one hour, often twice a week for six weeks. The exercise intensity will be monitored by the physiotherapist as determined by the participant's ability to complete 10 repetitions for a particular exercise and its difficulty of execution perceived by the modified Borg scale (CR-10). The exercises are performed with load between 60-80% of their capacity, the load will be increased from 2 to 10% when the patient can perform 14 full repetitions in the last series. It will be set to 30 seconds of rest between reps and 2 minutes between sets of exercise.

Both groups will perform prior heating exercises bike for 5 minutes with moderate intensity with the Borg scale. Then there will be one stretche repetitions held for 45 seconds of muscle groups: hamstrings, quadriceps, abductors, adductors and gastrocnemius. Thus, they will be performed strengthening exercises in extension and knee in open kinetic chain and squat.

The Posterolateral Hip Complex (PLC) add hip abduction exercise, Clam exercise and external rotation exercise. Studies prior point out that these exercises are among those withhigher electromyographic activity of the gluteus medius and maximus muscles.

The Anteromedial Hip Complex (AMC) add hip adduction exercise, adduction with a ring between the thighs and internal rotation exercise.

The exercises will be carried out to load 60-80% of 1 repetition maximum 8-12 reps, 1-3 sets and 2-3 times a week. All exercises are performed without worsening pain and intensity of exercise will be controlled according to the perceived exertion scale of Borg.

Eligibility Criteria:
Inclusion Criteria:

* Practicing physical activity for at least 3 times a week for at least 30 minutes;
* Pain localized specifically around the patellofemoral joint, pain reproduced or reported in at least two of the following criteria: up or down stairs, squatting, kneeling, sitting for a long time, isometric contraction of the quadriceps, jumping, running and pain on palpation of the lateral and / or medial facet of the patella;
* Report pain of insidious onset and lasting at least three months;
* Pain at least three in the Numerical Pain Scale during the last week;
* Report a maximum of 86 points on the Anterior Knee Pain Scale (maximum = 100 points).

Exclusion Criteria:

* Previous surgery on the hip, knee, ankle and / or spine;
* History of patellar dislocation;
* Clinical evidence of knee instability (anterior and posterior drawer test, Lachman, varus and valgus stress);
* Meniscal lesions or intra-articular lesions;
* Evidence of edema;
* Osgood-Schlatter syndrome or Sinding-Larsen-Johansson;
* Patellar tendinopathy;
* Chondral lesion;
* Osteoarthritis;
* Muscle or joint injuries to the hip.