The purpose of this study is to determine if interventions applied at a distant site, lumbopelvic region (manipulation and TENS), have a similar effect as interventions applied locally at the knee (TENS) on quadriceps force output and activation as well as reports of pain during common exercises in individuals with PFPS.

Interventions for PFPS usually focus on strengthening the quadriceps muscle and hip musculature. It is suggest that intervention programs specifically address muscle inhibition beyond typical strengthening exercises. To specifically address decreased muscle activation transcutaneous electrical neuromuscular stimulation (TENS), applied to the knee, has been shown to reduce pain and increase muscle activation in individuals with knee osteoarthritis. Interventions including joint manipulation applied at distant sites, such as the lumbopelvic region have also been shown to increase muscle activation following intervention in individuals with PFPS, but the duration of effect is unknown. It is hypothesized that interventions which alter spinal afferent signals may have an effect on efferent motor output. Since the lumbopelvic region and the knee joint share common nerve root levels it is possible that interventions applied to either site may influence efferent motor output to the quadriceps muscle. The magnitude and duration of this effect is unknown.

Both TENS and lumbopelvic manipulation have also been shown to reduce pain during exercise in individuals with knee joint pathology. This study would better determine the magnitude of effective pain reduction between interventions applied at the knee joint and at a distant site, the lumbopelvic region.

Inclusion Criteria:

• Age 15-50 years
• Insidious onset of patellofemoral pain lasting greater than 1 month in duration
• Unilateral or Bilateral knee pain or dysfunction with at least two of the following symptoms: patella compression, squatting, prolonged sitting, going up or down stairs, or isometric quadriceps contraction.

Exclusion Criteria:

• Participants who are outside of age range (to ensure bony maturity while reducing the prevalence of age related degenerative changes and hypomobility.)
• Ligamentous insufficiency, meniscus damage, patellar tendonitis, history of subluxation/dislocation
• Participants with traumatic spine or lower extremity injury within past 6 months
• Participants who have had previous adverse reactions to electrical stimulation (i.e. electrode burns.)
• Participants with signs indicating lumbar nerve root compression or upper motor neuron lesions (contraindication for lumbopelvic joint manipulation)
• Participants with ankylosing spondylitis (contraindication for lumbopelvic manipulation)
• Participants with spinal cord disease or cauda equina (contraindication for lumbopelvic manipulation)
• Participants with osteoporosis (contraindication for lumbopelvic joint manipulation)
• Participants with rheumatoid arthritis (contraindication to lumbopelvic joint manipulation.)
• Participants who may be currently pregnant. (contraindication for electrical stimulation and lumbopelvic joint manipulation.)
• Participants who have a demand-type cardiac pacemaker (contraindication for electrical stimulation)
• Participants with diagnosis of cancer (current cancer is a contraindication for electrical stimulation and relative contraindication for lumbopelvic joint manipulation)
• Participants who are unable to give consent or are unable to understand procedures of experiment.