Aquatic Biofeedback
Treatment of PFPS

Ron Fuller, PTA, ATRIC

Ronald A. Fuller is a registered physical therapy assistant and nationally certified aquatic therapist at HealthSouth Rehabilitation Hospital Outpatient Department in Concord, NH. He is on the faculty of the Biofeedback Foundation of Europe (BFE) and has authored several articles on aquatic rehabilitation. He has lectured at the national and international levels on aquatic treatment of orthopedic conditions, in addition to the use of aquatic biofeedback in the treatment of upper and lower extremity conditions. For more information on this course or the BFE, please log on to:  or contact the author at: Between 25–34 percent of the worlds population at one time or another will suffer from the debilitating pain of Patellofemoral Pain Syndrome (PFPS).8 From professional and olympic athletes, to weekend warriors and couch potatoes, this malady effects both the athletically inclined as well as the dynamically sublime. This diverse collection of symptoms has had several names such as chondromalacia patellae, patellofemoral arthralgia, infrapatellar fat pad syndrome and pre-patellar tendonitis. With the ever increasing draw of the sporting world combined with expanding numbers of computer enthusiasts, this malady will continue to plague the population as long as we continue to walk upright or remain seated for long periods of time.

Treatment on land has been varied, as has the success rate. The general consensus has been to utilize closed chain exercises and follow the McConnell theory of rehabilitation. This includes stretching tight musculature, correcting the patellofemoral arthro-kinematics, exercises to facilitate the Vastus Medialis Oblique (VMO) while inhibiting the Vastus Lateralis (VL) and biofeedback to re-train both the patient as well as the muscles.7, 9, 10, 15, 17

Studies have shown that early use of surface EMG in combination with exercise can increase peak torque values for knee extension, more than just exercise alone.3, 4, 6, 16 Several clinicians theorized that the use of surface EMG in this manner may help patients rehabilitate by, “increasing neural drive to the quadriceps and overcome inhibitory processes occurring in response to pain and edema.”2 It seemed natural to combine aquatic therapy and surface EMG in order to adjunct land-based therapy. By utilizing several physical properties of water (i.e. buoyancy and hydrostatic pressure) the pool becomes the perfect medium in which to unload the joint, relieve pain, decrease effusion and initiate exercise during the acute phase.

Aquatics has played a relatively minor role in the treatment of PFPS, primarily due to two reasons: 1) the inability of the therapist to specifically monitor the VMO/VL while in the pool and 2) knowing which aquatic exercises will achieve the specific desired effects. For several years, a union of the two modalities, biofeedback and aquatic therapy, had been casually explored and only superficially researched.1, 11, 12, 13, 14 Not until recently has there been a focused effort to combine and functionally utilize the water and surface EMG.

Brian Awbrey, MD and I recently published a research article showing the technique of aquatic biofeedback was valid and reproducible. It also showed the therapist could assess their patient’s progress quantitatively, allow the patient to effectively train while in the pool and ultimately, customize the treatment program to fit the individual needs of the patient.5 (Figure 1)

Aquatic biofeedback utilizes the same techniques and procedures as its land-based cousin. Skin preparation and electrode placement are still important, however the critical step is the application of a waterproof barrier to seal the electrode site. (Figure 2) The waterproof barrier is the key to aquatic biofeedback. It enables the therapist the opportunity to specifically direct treatments and collect quantitative data while the patient exercises in the water. Since the surface EMG unit is hand-held and powered by a 9-volt battery, the threat of electrocution is eliminated and site infiltration by water remains nothing more than a momentary light tingle. The possibility of saturating an expensive surface electrode however remains a more realistic hazard. The patient performs the exercise routine while, ‘wired-up.’ The therapist directs and records specific events of the treatment session. Threshold-based uptraining of either unilateral VMO/VL or bilateral VMO’s is performed on certain exercises with emphasis placed on the quality of contractions, increasing magnitude of contractions, improving timing of recruitment and resolution of dysfunction and pain.

The addition of aquatic therapy in the treatment of PFPS can provide an environment in which treatment can be initiated earlier, land-based exercises can be mastered sooner and specific skills can be advanced quicker. Aquatic biofeedback brings to the treatment regimen specificity, control, quantitative measurements and patient education.

Athlete and armchair artist alike will most likely suffer from PFPS at sometime in their lives. Quick treatment and rapid resolution of the symptoms is imperative. Aquatic therapy offers you the opportunity to treat them immediately; aquatic biofeedback allows you to treat them correctly.  

Exercises Phase I: 1-2 Weeks

Goals: Increase quadriceps recruitment, restore normal patterns of muscle synergy, increase magnitude, improve timing of VMO recruitment vs. VL, increase ROM and decrease pain.

Frequency: Two pool sessions and one land session per-week.

Equipment: Thigh cubes, balance board, thigh/ankle cuffs with long and short cords (Figure 3), MyoTrac 2, sensors, bioclusive dressing (Figure 4).

Note: Do not train through pain. Perform aquatic biofeedback on VMO and VL (or bilateral VMO’s). May require patella taping during pool session. Perform stretching exercises to appropriate muscles prior to exercises. Depending on the severity of symptoms, start with buoyancy assist and progress to buoyancy resist.

  1. SW  walking forward, backward and side-to-side (with mini-squat)

  • assess gait pattern for asymmetry, painful gait components and posturing

  • utilize cardinal plane motions, avoiding rotary movements during exercises in order to maintain correct patella tracking in trochlear notch

  1. SW  hip flex./ext. and abd./add.

  2. SW  bilateral heel raises

  3. SW  weight shifting forward/back and side-to-side

  4. SW  bilateral mini-squats with co-contractions* (Figure 5)

  5. SW  tethered 3-way mini-squats (short arcs)

  6. SW  standing knee flex./ext. with Hydrofit cuffs (back to wall)

  7. SW  step ups/downs at comfortable height* (Figure 6)

  8. SW  sit/stand

  9. DW  scissors (emphasis on maintaining full, comfortable knee extension)

  10. DW  abd./add. (crossing midline)

  11. DW single knee to chest

  12. DW  bilateral up, out, in, down (B.U.O.I.D.)

  13. DW  mini-squats (holding onto deck) *

  • foam thigh cubes between knees (Figure 7)

  • progress to balance board with foam between knees

  • experiment with different foot pronation/supination and hip medial/lateral rotation

  1. DW  simulated vertical bicycle or aquatic bicycle (if available)

*denotes aquatic biofeedback training
 SW - shallow water
 DW - deep water


Exercises Phase II: transition

Goals: Minimal to no pain with exercises, VMO/VL ratio 1:1 or better and full AROM.

Frequency: One pool session and two-land sessions per-week.

Note: Progress from small to large movements, slow to fast speeds and light to heavy resistance. As skill develops, incorporate multi-joint control, add distractions, randomize training activities and remove audio/visual feedback.

Equipment: Same as phase I

  1. SW walking forward, backward and side-to-side with Hydrofit cuffs

  • emphasis on proper posture, heel/toe gait pattern and slight over-emphasis of hip flexion and knee extension during toe-off and swing through phases

  • adjust number of cubes (in cuffs) to tolerance

  1. SW  braiding steps with/without Hydrofit cuffs

  • increase speed as tolerated (emphasis on quality, not quantity)

  1. SW  hip flex./ext. and abd./add. with Hydrofit cuffs

  2. SW  3 point lunges (forward, side, back)

  3. SW  tethered 3-way minisquats (deeper squats, if possible)* (Figures 8,9,10)

  4. SW  standing knee flex./ext. with Hydrofit cuffs (front to wall)

  5. SW  reverse – tethered ball catch (tethered at waist)

  • bilateral, then progress to single leg

  • reverse tethering to back

  1. SW  step ups/downs (decrease the effects of gravity)

  2. SW  bilateral 4-point hopping

  • slow to fast

  • add barrier to jump over

  1. DW  tethered scissors with ankle cuffs and short resistance bands* (Figures 11,12)

  2. DW  mini-squats (deeper squats) without holding onto deck

  • foam between knees on balance board*

  • "mutant penguin” mini-squats on single leg

  • mini-squat on balance board (Figure 13)

  • “mutant flamingo” mini-squats on balance board with hand buoys (Figure 14)

  1. DW  short-arc flutter kicks (tethered) with fins — timed bouts

The featured exercise routine is initiated as soon as possible in conjunction with the land-based program. Progression from phase I to phase II is contingent on VMO output, balance between VMO/VL and pain scale with activity. Exercises may be added, modified or deleted as needed (or tolerated) in order to fit the needs of your patient, pool or time constraints.

  1. Becker, K.M., Erlandson, M.O., Hemmesch, R.A., Redfield, D.S. (1996). A comparison of serratus anterior muscle activity during prone exercise in water and on land as measured by a clinical EMG unit. St. Paul, MN. : College of St. Catherine. (unpublished master’s thesis).

  2. Cram, J.R., Kasman, G., (1998). Knee Dysfunction. Clinical Applications in Surface Electromyography. (Aspen Publishers). Pg. 366

  3. Draper, B., Ballard, L. (1991). Electrical stimulation versus electromyographic biofeedback in the recovery of quadriceps femoris muscle function following ACL surgery. Phys Ther. 71: 455-463.

  4. Draper, V. (1990). Electromyographic biofeedback and recovery of quadriceps femoris muscle function following ACL reconstruction. Phys Ther. 9: 11-17

  5. Fuller, R.A., Awbrey, B.J., Dye, K.K., Cook, N.R. (1999). Activity level of the VMO during single leg mini squats on land and at varied water depths. Journal of Aquatic Physical Therapy. 7 (1): 13-18

  6. King, A.C., Ahles, T.A., Martin, J.E., White, R. (1984). EMG biofeedback-controlled exercise in chronic arthritic knee pain. Arch Phys Med Rehabil. 65: 341-343

  7. McConnell, J.S., (1996). Management of patellofemoral problems. Manual Ther. 1: 60-66

  8. McConnell, J.S. (1991). Patellofemoral Pain Syndrome. McConnell Patellofemoral Treatment Plan (course text). Pg.1

  9. McConnell, J.S. (1987). Proceedings of the Tenth International Conference of the WCPT (Sydney, Australia).

  10. McConnell, J.S. (1986). The management of chondromalacia patellae: a long term solution. Austr J Physiother. 32: 215-223

  11. Nuber, G.W., Jobe, F.W., Perry, J., Moynes, D.R., Antonelli, D. (1986). Fine wire electromyography analysis of muscles of the shoulder during swimming. Am J Sports Med. 14: 7-11

  12. Pink, M., Pery, J., Browne, A., Scovazzo, M.L., Kerrigan, J. (1996). The normal shoulder during freestyle swimming: an electromyographic and cinematographic analysis of twelve muscles. Am J Sports Med. 19(6) : 569-576

  13. Poteat,  A.L., Redfield, D.S., Erlandson, M.O., Becker, K.M., Hemmesch, R.A. (1996). Surface EMG: a method to examine land versus water shoulder exercises on muscle activity. (unpublished research). St. Paul, MN: St. Paul Ramsey Medical Center.

  14. Poteat, A.L., Redfield, D.S., Erlandson, M.O., Becker, K.M., Hemmesch, R.A. (1996). Quantification of aquatic physical therapy water-based methods: Part I: Surface electromyography. Journal of Aquatic Physical Therapy  4(1) : 13-17

  15. Shelton, G.L., Thigpen, L.K. (1991). Rehabilitation of patellofemoral dysfunction; a review of literature. J. Orthop Sports Phys. Ther. 14: 243-249

  16. Sprenger, C.K., Carlson, K., Wessman, H.C. (1979). Application of electromyographic biofeedback following medial menisectomy. Phys. Ther. 59: 167-169

  17. Stiene, H.A., Brosky,T., Reinking, M.F., Nyland, J., Mason, M.B. (1996). A comparison of closed kinetic chain and isokinetic joint isolation exercise in patients with patellofemoral dysfunction. J. Orthop Sports Phys. Ther. 24: 136-141

Address Correspondence to:
Ron Fuller, PTA, ATRIC
c/o HealthSouth Rehabilitation Hospital
254 Pleasant Street
Concord, NH 03301

Article reprinted with permission of the Sports Medicine Update magazine.





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