Date of Completion


Embargo Period



Lindsay Lepley, PhD, ATC Adam Lepley, PhD, ATC Craig Denegar, PT, ATC Giselle Aerni, MD

Field of Study



Master of Science

Open Access

Open Access



Examining altered neural activation in patients with patellar tendinopathy: a preliminary study

Davi SM, Lepley LK, Lepley AS, Denegar CR, Aerni G, DiStefano LJ: Human Performance Laboratory, Department of Kinesiology, University of Connecticut, Storrs, CT.

CONTEXT: Patellar tendinopathy (PT) is a common injury that can affect 15-45% of all athletes, with nearly 50% of these athletes reporting no longer being able participate in sport due to the severity of the injury. One of the consequences of PT leading to physical inactivity is muscular weakness, particularly in the quadriceps, which may be attributed to arthrogenic muscle inhibition (AMI). OBJECTIVE: To examine the extent of quadriceps AMI in individuals suffering from PT and secondly, to compare subjective reports of pain and dysfunction with objective measurements of PT diagnosis. DESIGN: Case-control. SETTING: Laboratory PARTICIPANTS: Six participants with diagnosed PT (- Patella (VISA-p) and six healthy participants (VISA-p>80) matched to the PT group based on age, mass, height, and gender. INTERVENTION: Each participant completed one test session, which included patient-oriented outcome questionnaires, diagnostic ultrasound (US), Hoffman’s Reflex (H-Reflex), superimposed burst to assess central activation ratio (CAR), and a standardized jump landing test. Neuromuscular control during the jump landing was evaluated using the Landing Error Scoring System (LESS) and electromyography (EMG) of the vastus medialis and lateralis. MAIN OUTCOME MEASURES: H:M ratio, CAR, LESS score, percent maximum muscle activation during CAR, and percent stance muscle activation during the pre-loading and loading phases of jump landing were assessed between groups using independent-t tests (αRESULTS: With respect to CAR, the PT group (95.13%±3.46) compared to the healthy group (98.54%±0.60) exhibited a significant loss of volitional muscle activation (P=.04). There were no differences between groups for H:M, LESS score, or muscle activity (P>0.05). The PT group was then divided into two sub-groups: Subjective (participants that were diagnosed with PT via subjective reports alone)(n=4) and Objective (participants that were diagnosed via subjective reports and US)(n=2). The Objective group demonstrated lower CAR, H-Reflex, muscle activity, and a higher LESS score than both the Subjective PT group and the healthy group. CONCLUSION: This study was the first to demonstrate deficits in the PT population using measures of peripheral sources of AMI. Further research needs to be conducted on the extent of these deficits and whether AMI induced from PT is associated with an increased risk of lower extremity injury.

Key Words: neuromuscular dysfunction, cortical alterations, peripheral inhibition

Major Advisor

Lindsay Distefano, PhD, ATC