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Completed

NCT Number: NCT04480528

Strength Training in Female Runners With Patellofemoral Pain

Patellofemoral pain (PFP) is a common running-related injury that is often referred to as runner's knee. The condition typically presents with pain in the front of the knee that is located around or behind the knee cap. This injury occurs twice as frequently in females and is often associated with weakness of the muscles of the thigh and hip, as well as altered running form. Heavy-weight strength training is needed in order to improve muscle weakness; however, this puts a significant amount of load on the knee joint and it is difficult for individuals with PFP to train at this level without experiencing increased pain and joint discomfort. Blood flow restriction training (BFRT) is a promising alternative method to safely improve muscle weakness while reducing knee joint loading. With BFRT, a pressurized band is applied to the thigh in order to partially restrict blood flow as a patient exercises in order to decrease the amount of oxygen delivered to the muscle. Lack of oxygen to the muscle combined with strength training creates an environment within the muscle that results in the ability of low-weight strength training to provide the same results as heavy-weight strength training.

This study will evaluate how low-weight strength training with and without BFRT affects thigh and hip strength, and consequently pain, function, running ability, and running form in female runners with PFP. The hypothesis is that 10 weeks of low-weight strength training with BFRT will lead to greater thigh and hip strength, reduced pain, improved knee function, improved running ability, and improved running form compared to low-weight strength training without BFRT. The expected results will have a significant impact within the running community by providing a safe and effective treatment that increases strength and improves running form while reducing pain and joint loading. This will also have an impact on the larger field of sports medicine by providing an alternative method to improve strength, as well as improve function when heavy-weight strength training is not well tolerated or unsafe due to injury.

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Key information

Conditions

Patellofemoral Syndrome Joint Diseases Musculoskeletal Diseases Patellofemoral Pain Syndrome

Age range

18 year–50 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

University of Kentucky

Lexington, Kentucky, 40536, United States

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Pain around (peripatellar) or behind (retropatellar) the patella, which is aggravated by running and at least one other activity that loads the patellofemoral joint during weight bearing on a flexed knee such as kneeling, squatting, stair ambulation, and jumping/hopping
  • Insidious onset of symptoms unrelated to trauma
  • Pain present for at least 2 months
  • Pain rating of at least 3/10 on the visual analog scale during running
  • Report running at least 10 miles per week currently or just prior to onset of injury
  • Score a maximum of 85% on either the Knee Outcome Survey Activities of Daily Living Scale or Sports Activity Scale (KOS-ADL or KOS-SAS)

Exclusion criteria

  • Knee pain resulting from acute trauma
  • Concurrent ligamentous instability, meniscus pathology, patellar or iliotibial band tendinopathy
  • History of patellar dislocations or instability, or previous reconstructive surgery to the knee
  • Other lower extremity or lower back injury within the past 6 months

Treatment and study plan

Blood Flow Restriction Training (BFRT)

Other

A pressurized cuff is applied to the proximal thigh in order to partially occlude blood flow as the patient exercises.

Sham Blood Flow Restriction Training (Sham BFRT)

Other

A minimally pressurized cuff is applied to the proximal thigh in order to mimic the active blood flow restriction unit as the patient exercises.

Primary outcomes

  1. Change in Isometric Quadriceps Strength

    Time frame: 10 weeks

    The subject will be seated in a Biodex 4 dynamometer with their knee locked at 90 degrees of flexion. The subject will be asked to kick into the dynamometer pad as hard as they can and the peak force will be measured and normalized to body weight. Increased force indicates greater quadriceps strength.

  2. Change in Isokinetic Quadriceps Strength

    Time frame: 10 weeks

    The subject will be seated in a Biodex 4 dynamometer and be asked to kick back-and-forth into the dynamometer pad as hard and as fast as they can. The peak force will be measured and normalized to body weight. Increased force indicates greater quadriceps strength.

  3. Change in Isometric Hip Abduction Strength

    Time frame: 10 weeks

    The subject will be lying in the side-lying position with a stabilizing strap placed around the thigh. The subject will be asked to press out as hard as they can against a handheld dynamometer which records the force applied against it. The peak force will be measured and normalized to body weight. Increased force indicates greater hip abduction strength.

  4. Change in Isometric Hip Extension Strength

    Time frame: 10 weeks

    The subject will be lying on their stomach with their knee flexed to 90 degrees and a stabilizing strap placed around the thigh. The subject will be asked to press up as hard as they can against a handheld dynamometer which records the force applied against it. The peak force will be measured and normalized to body weight. Increased force indicates greater hip extension strength.

  5. Change in Isometric Hip External Rotation Strength

    Time frame: 10 weeks

    The subject will be seated with their knee flexed to 90 degrees and a stabilizing strap placed around the lower leg. The subject will be asked to press inward as hard as they can against a handheld dynamometer which records the force applied against it. The peak force will be measured and normalized to body weight. Increased force indicates greater hip external rotation strength.

Secondary outcomes

  1. Change in Hip Adduction Angle

    Time frame: 10 weeks

    Change in peak hip adduction angle will be measured via a three-dimensional running gait analysis on an instrumented treadmill.

  2. Change in Hip Internal Rotation Angle

    Time frame: 10 weeks

    Change in peak hip internal rotation angle will be measured via a three-dimensional running gait analysis on an instrumented treadmill.

  3. Change in Peak Knee Extensor Moment

    Time frame: 10 weeks

    Change in peak knee extensor moment will be measured via a three-dimensional running gait analysis on an instrumented treadmill.

  4. Change in Pain: Brief Pain Inventory (BPI)

    Time frame: 10 weeks

    Pain will be measured using the Brief Pain Inventory (BPI), which assesses pain (least, most, average, and present pain) on a scale from 0-10. Lower numbers indicate less pain while higher numbers indicate more pain.

  5. Change in Patellofemoral Pain: Knee Injury and Osteoarthritis Outcome Score

    Time frame: 10 weeks

    Patellofemoral pain will be measured using the Knee Injury and Osteoarthritis Outcome Score - Patellofemoral Pain. It is an 11-item questionnaire and items are coded from 0 to 4, no problems to extreme problems. Scores are transformed to a 0-100 scale and represent the percentage of total possible score achieved. Lower numbers indicate greater knee patellofemoral pain while higher numbers indicate less patellofemoral pain.

  6. Change in Knee Function

    Time frame: 10 weeks

    Knee function will be measured using the Knee Injury and Osteoarthritis Outcome Score (KOOS) which contains 5 subscales: Pain - 9 items, other Symptoms - 7 items, Function in daily living (ADL) - 17 items, Function in Sport and Recreation (Sport/Rec) - 5 items, and knee-related Quality of Life (QoL) - 4 items. Items are coded from 0 to 4, no problems to extreme problems. Scores are transformed to a 0-100 scale and represent the percentage of total possible score achieved. Lower numbers indicate greater knee problems while higher numbers indicate less knee problems.

  7. Change in Running Ability

    Time frame: 10 weeks

    Running ability will be measured using the University of Wisconsin Running Injury and Recovery Index (UWRI). It is a 9-item questionnaire and items are coded from 0 to 4, lower scores indicating an inability to run and higher scores indicating no pain/issue with running. Scores are transformed to a 0-100 scale and represent the percentage of total possible score achieved. Lower numbers indicate limited running ability while higher numbers indicate full running ability.

Sponsors and collaborators

Lead sponsor

Lauren Erickson

Other

Collaborators

  • American College of Sports Medicine

Registry information

Official study title

The Effect of Various Strength Training Protocols in Female Runners With Patellofemoral Pain

Important dates

Study start
2020
Primary completion
2021
Study completion
2021
First posted
Jul 21, 2020
Registry last updated
Mar 4, 2022

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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