Changes in Quadriceps Function Following Local or Distant Interventions in Individuals With Patellofemoral Pain

The lumbopelvic joint manipulation (Grade V mobilization) will be performed on the ipsilateral side of the test limb. The participant will be passively side-bent towards and rotated away from the selected lumbopelvic region which is followed by the delivery of a posterior/inferior force through the opposite anterior superior iliac spine. If a cavitation is not heard or felt by the patient or clinician, the technique will be repeated. If the second attempt does not produce cavitation the procedure will be repeated on the contralateral side using similar methods. If cavitation is not heard or felt by the participant or clinician following the second attempt on the contralateral side, the participant will proceed with the assessment of quadriceps strength and activation as usual.

The TENS electrodes will be applied lateral to L1 and L2 and lateral to S5 and S1. The TENS unit will be set to deliver a continuous TENS biphasic pulsatile current at 150 Hz, with a phase duration of 150 microseconds. The TENS unit will be worn during all exercise testing and for the first 30 minutes of quadriceps force output and activation testing. After the 30 minute post-intervention measures (Post30) are obtained, the TENS unit will be turned off.

The TENS electrodes will be applied on the medial and lateral superior, as well as the medial and lateral inferior, borders of the patella. Care will be taken not to place TENS electrodes on the quadriceps muscles or muscles of the anterior leg. The TENS unit will be set to deliver a continuous TENS biphasic pulsatile current at 150 Hz, with a phase duration of 150 microseconds. The TENS unit will be worn during all exercise testing and for the first 30 minutes of quadriceps force output and activation testing. After the 30 minute post-intervention measures (Post30) are obtained, the TENS unit will be turned off.