Quadriceps Strengthening At Different Angles in Patellofemoral Pain

Summary

Introduction: Patellofemoral pain (PFP) is characterized by anterior, retropatellar and/or peripatellar pain during activities such as running, squatting, kneeling, or prolonged sitting. This condition affects approximately 25% of the general population. Given its complex and multifactorial etiology, PFP presents a significant treatment challenge. All clinical practice guidelines recommend strengthening the quadriceps femoris muscle as a key component in the management of PFP. However, exercises aimed at strengthening the quadriceps place considerable stress on the patellofemoral joint and are often poorly tolerated by patients. Clinicians commonly employ a conservative strategy that restricts open kinetic chain knee extension exercises to a limited range of 90° to 45° of knee flexion and closed kinetic chain exercises to 0° to 45°. Yet, restricting the range of motion may result in suboptimal outcomes for patients with higher load tolerance and may foster beliefs regarding knee joint fragility.

Objective: We aim to compare the effects of quadriceps femoris strengthening within a limited range to a patient-guided range of motion on pain, function, knee confidence, and kinesiophobia in individuals with PFP.

Methods: A randomized clinical trial will be conducted with two parallel groups, using a balanced 1:1 allocation and a double-blind design. The study population will include men and women aged 18 to 35 years, diagnosed with PFP. Participants will be randomly assigned to either the limited range group or the patient-guided range of motion group. They will participate in a supervised therapeutic protocol, with sessions averaging 40 minutes, twice a week, for six consecutive weeks. The primary outcome will be pain, assessed using the numerical pain rating scale (0-10), and kinesiophobia, assessed by the Tampa Scale . Secondary outcomes will include pain, self-reported function, measured by the Anterior Knee Pain Scale (AKPS), perceived improvement by the Global Rating of Change Scale, quadriceps strength, kinesiophobia and analgesic consumption.

Conditions

• Patellofemoral Pain Syndrome

Interventions

OTHER

Protected Range Quadriceps Strengthening group

Warm-up: Start with 5 minutes of stationary biking. Then, proceed with two sets of 30-second dynamic stretches targeting the quadriceps, hamstrings, calf muscles, and adductors, followed by static stretching for the abductors. Strengthening: Complete 3 sets of 8-12 repetitions for each exercise, aiming for a perceived effort level on the Borg scale between 60% and 80%. Increase the load by 2%-10% when the patient can perform 14 or more repetitions in the final set while maintaining the Borg scale between 60% and 80%. For the Leg Extension Machine, maintain a range of motion between 90 to 45 degrees. During Squats and Bulgarian Squats, aim for a range of motion between 0 to 45 degrees.

OTHER

Patient-Guided Range Quadriceps Strengthening group

Warm-up: 5 minutes of stationary biking. Next, perform two sets of 30-second stretches for the quadriceps, hamstrings, calf muscles, adductors and abductors hip. Strengthening: Patients will complete 3 sets of 8 to 12 repetitions for each exercise, aiming for a perceived effort level of 60% to 80% on the Borg scale. Load will be increased by 2% to 10% when patients can complete 14 or more repetitions in the final set while maintaining the Borg scale between 60% and 80%. Quadriceps strengthening will be performed at the patient's maximum range guided by symptoms, with pain intensity capped at 5 points on the NPRS. The patient-guided range will be adjusted based on pain intensity, comfort, and patient response, using a shared decision-making approach. The goal is to maintain exercises at the maximum possible range of motion. For the Leg Extension Machine, Squats, and Bulgarian Squats, the range of motion will be guided by the patient's pain tolerance.

Sponsors & Collaborators

• Universidade Federal do Ceara

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

35 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2024-10-26

Primary Completion

2024-12-31

Completion

2026-06-30

Countries

• Brazil

Study Locations