The relevance of this study is to determine the effects of a patellar taping on muscle activation of the vastus medialis oblique (VMO), vastus lateralis (VL) and gluteus medius (GM) during different proprioceptive exercises frequently utilized in rehabilitation program.

The purpose of this study is to assess the role of the patellar taping on muscle activation during seven proprioceptive exercises in women with the patellofemoral pain syndrome.

Forty voluntary young women (from 18 to 35 years) with three or more clinical symptoms of patellofemoral pain syndrome will be recruited. The participants will answer a clinical questionnaire in regard to knee pain and a specific patellofemoral questionnaire titled: the Anterior Knee Pain Scale (AKPS). All participants will sign an informed consent form approved by the North of Parana University Ethics Committee for Research on Human Subjects. The sample will be randomized in two groups: (G1) the experimental group that will use a rigid patellar taping (n = 20) for the correction in lateralization of the patella and stabilization of the knee. The lateral stabilization will be made with self-adhesive taping positioned in the lateral border of the patella and tensioned in relation to the medial portion of the femur condyle, which allows an edge of the medial board patella and a stretching of lateral structures of the knee. All procedure will follow the recommendation from McConnell studies with regard to the patellar femoral syndrome; and (G2) the placebo group that will use a rigid patellar taping (n = 20), but without no correction of lateralization of the patella and/or stabilization of the knee. The taping will be placed incorrectly such as in the vertical position of knee and without any tension or traction around structures and patella. A computer will be used to generate the randomization sequence of the participants. The allocation will be printed in cards by sequentially numbered in opaque envelopes.

Before performing the exercises, a maximum voluntary isometric contraction will be performed for the knee extensor muscles (e.g. specifically the VMO and VL) and hip abductor muscles (e.g. GM) in order to normalize the signal EMG for determining of the level muscular activity during each exercise, with the correct taping and/or placebo. All participants, after randomization, will perform seven proprioceptive exercises on one leg-stance position in different surfaces: 1) static position in force platform, 2) dynamic in flexion-extension knee on a force platform, 3) anteroposterior sway on rectangular rocker board, 4) mediolateral sway on rectangular rocker board, 5) unipodal standing on a swing apparatus, 6) unipodal standing on a mini-trampoline, and 7) unipodal standing on bosu balance ball. Each exercise has a time of 15 seconds performance, while sway centre of pressure parameters will be computed (exercise #1 and #2), and EMG surface will recording (VMO, VL, GM) for all seven. First, one baseline measure (without taping) will be performed and immediately after with the use of taping (intervention or placebo).

An ANOVA two-way will be performed to compare the two groups (G1 and G2) and two times (before and immediately after with taping) and the effects of interaction (Groups x Times). The size effect also will be computed to determine the rate of the changes observed.

Inclusion Criteria:

• anterior or retropatellar knee pain on at least two of the following activities: prolonged sitting, stairs, squatting, running, kneeling, and hopping/jumping,
• pain on patellar palpation,
• pain while stepping down from a 25-cm step or during a double leg squat,
• symptoms for at least 1 month, average pain level of 3 cm or more on a 10-cm VAS.

Exclusion Criteria:

• signs or symptoms of other pathology including coexisting pathology, a recent history (within 3 months) of knee surgery,
• history of patellar dislocation/subluxation, or clinical evidence of meniscal lesion, ligamentous instability, traction, apophysitis around the patellofemoral complex, patellar tendon pathology, chondral damage, osteoarthritis, or referred pain from the spine, features that could affect the implementation of the trial,
• previous experience with patellar taping, an inability to attend a physical therapy clinic for a 6-wk treatment program,
• allergic reaction to adhesive tape,
• pregnancy, and an inability to understand the experimental protocol.