An observational study in Quadriceps Muscle Atrophy and Leg Injury, sponsored by Andrews Research & Education Foundation. Completed at 1 site in United States. Open to participants aged 18 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-02.
Sponsored by Andrews Research & Education Foundation · Observational
The goal of this study is to compare quadriceps muscle activation in patients recovering from lower extremity injury, such as an ACL tear. Specifically, the main objectives are as follows:
Returning quadriceps neuromuscular control and preventing atrophy is an area of intense current interest in orthopedic rehabilitation and recovery science. It is clear that returning full autonomous control of the quadriceps, including the vastus medialis obliqus (VMO), at full knee extension is an important factor in rehab and dysfunction of the quadriceps leads to a loss of physical performance and self-reported function. Quadriceps function is critical for optimal ambulation patterns and eccentric control is essential for the weight acceptance phase of gait.
Quadriceps atrophy is one of the most common post-operative side effects of anterior cruciate ligament (ACL) reconstruction, total knee arthroplasty, and many other surgeries including meniscal repairs, patella realignment procedures, and microfracture procedures. Due to the swelling within the joint after injury or surgery to the knee, the joint inflammation cascade occurs and leads to the quadriceps being arthrogenically inhibited by spinal neuron inhibition as a protective mechanism. These neural changes usually lead to decreased voluntary quadriceps contraction. Additional contributions of inhibition from post-operative pain, patient apprehension, and surgical procedure requiring protection of the repaired tissue. The sooner one regains control of the quadriceps muscles the less atrophy occurs, reductions in strength are minimized, and the more optimal the outcome is achieved for patient recovery.
Studies have shown that neuromuscular electrical stimulation (NMES), Transcutaneous electrical nerve stimulation (TENS), and biofeedback techniques can limit post-operative quadriceps atrophy and can return strength of the quadriceps back to normative values faster than without those techniques and traditional therapeutic exercise and have better long-term outcomes based on pain, functional outcomes, and return to sport participation rates.
Irradiation effect is a proprioceptive neuromuscular facilitation technique that causes an overflow of neuronal energy from distal to proximal muscles to increase muscle activity of a targeted muscle. This technique can be used to selectively recruit weaker motor units through the application of resistance or stimulation. By inducing a stronger contractile force of the quadriceps, our hope is to return quadriceps function to normal quicker with less atrophy and greater strength.
The investigators hypothesize that ankle positioning in maximal dorsiflexion (DF) changes the quantity of contraction as a percent of the reference voluntary contraction when performing a supine straight leg raise compared with having the foot in neutral (0°), relaxed, and plantarflexed (PF) positions. This may help provide insight into proper instruction and cuing for patients to return quadriceps neuromuscular control sooner and thus limiting quadriceps atrophy.
65 studies on the registry are indexed under Leg Injuries; 12 are open to participants now.
This study's enrollment of 116 is below the median of 200 across 17 observational studies indexed under Leg Injuries.
Browse Leg Injuries studies →Andrews Research & Education Foundation is the lead sponsor of 20 studies on the registry; 2 are open to participants now.
Of its 6 completed or terminated interventional studies of FDA-regulated products, 4 (67%) have results posted.
Counted across the registry records on this site, refreshed daily.
The study population consists of two groups of 50 individual participants each. These groups are healthy participants and participants who have recently undergone knee arthroplasty.
(All Participants)
Inclusion Criteria:
Exclusion Criteria:
(Healthy Participants)
Exclusion Criteria:
Patients without pre-existing lower extremity injury that may inhibit response to testing
Other: Straight Leg Raise exercise
Patients who have recently suffered knee injury that required arthroscopic surgery
Other: Straight Leg Raise exercise
Patient lying supine will lift leg to the height of the contralateral knee flexed to 90 degrees with the ankle positioned and tested in all three positions (dorsiflexion, neutral, and plantarflexion)
Noraxon Ultium EMG
Visually monitors and records electromagnetic signals from muscle activation using diodes placed on patient
Time frame: Within first 28 days post-op (Arthroscopy patients); healthy patients tested at enrollment
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is completed, as verified in Oct 2025. You cannot join it, but the record below documents what was studied.
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Andrews Research & Education Foundation