An interventional study of Isometric Exercise and Sham Transcutaneous Electrical Nerve Stimulation in Tendinopathy, sponsored by University of North Carolina, Chapel Hill. Completed at 1 site in United States. Open to male participants aged 15 Years to 28 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2019-02-19.
Sponsored by University of North Carolina, Chapel Hill · Not applicable, Interventional, and Treatment
The purpose of this study is to determine differences in lower extremity landing biomechanics and real-world physical activity between individuals with patellar tendinopathy compared to individuals without patellar tendinopathy,and to determine the acute effects of an isometric loading intervention on lower extremity landing biomechanics in individuals with patellar tendinopathy.
The investigators will recruit a convenience sample of participants who meet the following overall criteria:
Exclusion Criteria:
The following exclusion criteria will be applied to all participants:
Pubertal Development Scale Score \< 12 (Stages 1-4)
The participant will perform 5 sets of a 45-second isometric contractions at 70% of their maximum voluntary isometric contraction (MVIC). During the 45-second contraction, the participant will be provided with visual biofeedback on a computer screen (70% MVIC target line and +/- 5% error lines). The participant will be instructed to produce a level of isometric quadriceps contraction that maintains the isometric torque output line as close the target line as possible and always between the two error lines.
Other: Isometric Exercise
Two electrodes of the Select System TENS unit (Empi, Inc., St. Paul, MN) will be placed on either side of the patellar tendon on the test limb. The same instruction script will be used for each participant, stating, "A surface electrode has been placed on either side of your patellar tendon. I will turn on the stimulation unit to emit a stimulus to your patellar tendon. This is a special sub-sensory stimulation treatment, so you will not feel anything during this period as the stimulus is set at a very low, non-detectable threshold. Please remain still during this 45-second period, letting your leg rest passively in the machine without contracting your leg muscles. After the 45-second period, the stimulation unit will be turned off and you will have a 2-minute rest period. We will repeat this same treatment/rest sequence 5 total times."
Other: Sham Transcutaneous Electrical Nerve Stimulation
5 sets of 45-seconds quadriceps contraction, each followed by 2-minutes of rest.
Also known as: Therapeutic Exercise
5 sets of 45-seconds intervals without quadriceps contraction, each followed by 2-minutes of rest.
Also known as: Sham TENS
Difference in the change in mean internal knee extension moment during landing between groups
Angular force or moment will be measured in Nm/kg\*m where "Nm" represents angular force and "kg\*m" represents normalization to body weight and height.
Time frame: Pre- and post-intervention condition (~30 minutes)
Difference in the change in mean internal hip flexion moment during landing between groups
Angular force or moment will be measured in Nm/kg\*m where "Nm" represents angular force and "kg\*m" represents normalization to body weight and height.
Time frame: Pre- and post-intervention condition (~30 minutes)
Difference in the change in mean peak vertical ground reaction force during landing between groups
Vertical ground reaction force will be measured in N(BW) where "N" is a measure of force and "BW" represents normalization to body weight.
Time frame: Pre- and post-intervention condition (~30 minutes)
Difference in the change in mean peak vertical ground reaction force loading rate during landing between groups
Vertical ground reaction force loading rate will be measured in N(BW)/s where "N" is a measure of force and "BW" represents normalization to body weight and "s" is the time unit seconds.
Time frame: Pre- and post-intervention condition (~30 minutes)
Difference in the change in mean peak patellar tendon force during landing between groups
Patellar tendon force will be measured in N(BW) where "N" is a measure of force and "BW" represents normalization to body weight.
Time frame: Pre- and post-intervention condition (~30 minutes)
Difference in average steps-per-day between groups
Steps-per-day calculated by an ActiGraph GT9X Link Accelerometer (ActiGraph Corporation, Pensacola, FL) wearable physical activity device worn at the hip using a belt clip.
Time frame: Day 1 - Day 7
Difference in average minutes of moderate-to-vigorous physical activity (MVPA) between groups
MVPA calculated by an ActiGraph GT9X Link Accelerometer (ActiGraph Corporation, Pensacola, FL) wearable physical activity device worn at the hip using a belt clip.
Time frame: Day 1 - Day 7
Difference in change in anterior knee pain (self-reported via visual analog scale (0-10)) between groups
A standard visual analog scale (0-10) will be utilized to assess pain, where 0=complete absence of pain and 10=worst pain imaginable (higher scores indicate worse pain). This scale will be delivered verbally and the participants will respond verbally.
Time frame: Pre- and post-intervention condition (~10 minutes)
Plan to share: Undecided
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University of North Carolina, Chapel Hill