Description Of Course Content:  The purpose of this workshop is to synthesize an understanding of knee rehabilitation techniques and their effects on knee tissue biomechanics using current scientific and empirical data.

Rehabilitation exercises, such as the squat, leg press, and knee extensions, are commonly prescribed after knee injuries or surgeries, such as ACL reconstruction (4).  However, it is often unclear which exercises are most effective in enhancing a patient’s knee rehabilitation, and how different exercises load knee structures.  Knowledge of knee force and muscle activity information during rehabilitation exercises will assist in selecting appropriate exercises and ranges of knee motion (1, 2, 5-7).  In addition, employing varying techniques while performing rehabilitation exercises has been shown to affect knee biomechanics (3).  Since it is difficult to understand or know precisely how technique variations affect knee forces and muscle activity during rehabilitation exercises, current data on knee biomechanics while performing exercises with varying techniques will be helpful in prescribing appropriate exercise techniques according to specific knee pathologies.

This workshop will discuss the effects of knee rehabilitation exercises on knee forces and muscle activity, as well as the role of rehabilitation exercises in strengthening and healing knee structures.  The information from this session will aid physicians, therapists, and trainers in prescribing specific exercises and techniques for specific knee pathologies during knee rehabilitation.  This information will also assist biomechanists who instruct course content related to knee rehabilitation or biomechanists who work with injured persons in research or practice.

Learner-Based Objectives:
 i. Discuss and illustrate patellofemoral compressive forces, tibiofemoral compressive forces, ACL/PCL tensile forces, and muscle activity between common open and closed kinetic chain exercises
 ii. Discuss and illustrate the effects of varying exercise technique on patellofemoral compressive forces, tibiofemoral compressive forces, ACL/PCL tensile forces, and muscle activity during common knee exercises with emphasis on the squat and leg press exercises
 iii. Discuss and illustrate cruciate ligament loads during common rehabilitation exercises especially the squat and knee extension after ACL reconstruction
 iv. Discuss and illustrate the role of knee rehabilitation exercises in facilitating healing and strengthening knee structures especially the ACL.
 
Course/Session Format
a. Outline of the session
 
Introduction - 10 minutes

Knee Forces and Muscle Activity During Open and Closed Kinetic Chain Exercises
30 minutes (includes 5-10 minute discussion period)

An Integrated Approach to Open Kinetic Chain, Closed Kinetic Chain, and Neuromuscular Exercises for the Knee Rehabilitation Patient
20 minutes (includes 5 minute discussion period)
 
The Effects of Technique Variations on Knee Forces and Muscle Activity During the Squat and Leg Press
30 minutes (includes 5-10 minute discussion period)

10 minutes, Break

The Clinical Relevance of Exercise Technique
45 minutes (includes mini-lab session for audience participation)

Beyond the Knee: How Can the Rest of the Lower Extremity Affect the Knee and its Rehabilitation?
30 minutes (includes 5-10 minute discussion period)

Summary and Further Discussion
15 Minutes

Description of Interactive Teaching/Learning Methods: Hands on demonstrations illustrating proper rehabilitation exercise techniques and methods will be performed throughout the workshop.  Participants will practice with each other while instructors monitor exercise and rehabilitation techniques and provide instructional feedback.

References Relevant to Workshop Title
1. Beynnon, B.D., R.J. Johnson, B.C. Fleming, C.J. Stankewich, P.A. Renstrom, and C.E. Nichols. The strain behavior of the anterior cruciate ligament during squatting and active flexion-extension: A comparison of an open and a closed kinetic chain exercise. Am J Sports Med. 25(6):823-829, 1997.
2. Escamilla, R.F., G.S. Fleisig, N. Zheng, S.W. Barrentine, K.E. Wilk, and J.R. Andrews. Biomechanics of the knee during closed kinetic chain and open kinetic chain exercises. Med Sci Sports Exerc. 30(4):556-569, 1998.
3. Escamilla, R.F., N. Zheng, G.S. Fleisig, et al. The effects of technique variations on knee biomechanics during the squat and leg press. Med Sci Sports Exerc. 29(5):S156, 1997.
4. Shelbourn, K.D. and P. Nitz. Accelerated rehabilitation after anterior cruciate ligament reconstruction. Am J Sports Med. 18(3):292-299, 1990.
5. Snyder-Mackler, L., P.F. De Luca, P.R. Williams, M.E. Eastlack, and A.R. Bartolozzi, 3rd. Reflex inhibition of the quadriceps femoris muscle after injury or reconstruction of the anterior cruciate ligament. J Bone Joint Surg Am. 76(4):555-560, 1994.
6. Wilk, K.E., R.F. Escamilla, G.S. Fleisig, S.W. Barrentine, J.R. Andrews, and M.L. Boyd. A comparison of tibiofemoral joint forces and electromyographic activity during open and closed kinetic chain exercises. Am J Sports Med. 24(4):518-527, 1996.
7. Yack, H.J., C.E. Collins, and T.J. Whieldon. Comparison of closed and open kinetic chain exercise in the anterior cruciate ligament-deficient knee. Am J Sports Med. 21(1):49-54, 1993.
  8.        Chinworth, S., Wilkerson, J., Hinrichs, R., & Jackson, A. Ground reaction forces and
 ankle and knee moments during rope skipping. Med Sci Sports Exerc. 22(2), 1990.
9. Chinworth, S. A. & Pope, P. G. Does changing resistance change
 quadriceps/hamstring ratio during stationary bike riding? Physical Therapy, 77(5):
  S75, 1997.
10. Chinworth, S., Wilkerson, J. Joint forces of the knee in non-injured and injured
 subjects while riding stationary bicycle. Med Sci Sports Exerc, 30(5): 1998.
11. Escamilla, R.F.  Knee biomechanics of the dynamic squat exercise. Med Sci Sports
Exerc, (in press).
12. Zheng, N., Fleisig, G.S., Escamilla, R.F., Barrentine, S.W.  An analytical model of
the knee for  estimation of internal forces during exercises.  J. Biomech.,
 31(10):963-7, 1998.
13. Wilk, K.E., Escamilla, R.F., Fleisig, G.S., Arrigo, C.A., & Barrentine, S.W.  Open
and closed kinetic chain exercise for the lower extremity: theory and clinical
application.  Athletic Training, 1(4): 336-346, 1995.
14. Escamilla, R.F., Zheng, N., Fleisig, G.S., Lander, J.E., Barrentine, S.W., Cutter,
G.R., & Andrews, J.R.  The effects of technique variations on knee biomechanics
during the squat and leg press.  Med Sci Sports Exerc, 29(5S): S156, 1997.

Speakers:
Rafael Escamilla, Ph.D., C.S.C.S.
Assistant Professor
Duke University Medical Center
Division of Orthopaedic Surgery
P.O. Box 3435
Durham, NC  27710
work: 919-684-1853
fax: 919-681-7067
e-mail: rescamil@duke.edu

 
Sue Chinworth, P.T., Ph.D.
Assistant Professor
Elon College
Department of Physical Therapy Education
2085 Campus Box
Elon College, NC 27244-2020
work: 336-278-6353
e-mail: chinwort@elon.edu

Brief Biographical Descriptions

Rafael Escamilla, Ph.D., C.S.C.S.:  Dr. Rafael Escamilla has extensive research experience in closed kinetic chain exercises.  During his five year tenure at the American Sports Medicine Institute (ASMI) in Birmingham, AL, and at Duke University Medical Center, Dr. Escamilla collaborated on open and closed kinetic chain knee exercise studies with biomedical engineers Dr. Glenn S. Fleisig and Dr. Nigel Zheng, world renowned orthopaedic surgeon Dr. James R. Andrews, and HealthSouth Corporation National Research Director Kevin E. Wilk, P.T.  Dr. Escamilla was the lead author in a study entitled “Biomechanics of the Knee during Closed and Open Kinetic Chain Exercises, which was recently published in Medicine and Science in Sports and Exercise (2).  Examining knee forces and muscle activity in the leg press, barbell squat, and knee extension exercises, Dr. Escamilla and co-authors quantified: 1) tibiofemoral compressive forces; 2) PCL/ACL tensile forces; 3) patellofemoral compressive forces; and 4) normalized electromyographic comparisons among the rectus femoris, vastus lateralis, vastus medialis, semitendinosus/semimembranosus, and gastrocnemius.  Dr. Escamilla was also a co-author in their initial closed/open kinetic chain exercise study entitled “A Comparison of Tibiofemoral Joint Forces and Electromyography Activity during Open and Closed Kinetic Chain Exercises”, published in the American Journal of Sports Medicine (6).  In these two studies Dr. Escamilla and co-authors developed mathematical models of the knee allowing them to estimate the forces generated across the articulating surface of the knee while performing closed and open kinetic chain exercises.  These mathematical knee models they developed for these exercises were recently published in the Journal of Biomechanics (12), entitled “An Analytical Model of the Knee for Estimation of Internal Forces During Exercise”.  Dr. Escamilla and co-authors continue to work on developing and improving mathematic knee models that can be used during therapeutic exercise.  Dr. Escamilla also has a physical therapy background in addition to his training in biomedical engineering and biomechanics, and is currently completing an Master of Physical Therapy degree.  His experience in Physical Therapy is helpful in understanding the current trend in knee rehabilitation exercises.

Susan A. Chinworth, P.T., Ph.D.:  Dr. Chinworth has over 20 years experience as a practicing physical therapist.  Her expertise is in Physical Therapy Orthopaedics, and has given several presentations related to knee biomechanics and the lower extremity.  She has also published several papers in the area of lower extremity biomechanics.  Dr. Chinworth’s teaching experience in Physical Therapy Orthopaedics has allowed her to acquire numerous insights in knee biomechanics and rehabilitation

Prior Speaking Experience:
Rafael Escamilla, Ph.D., C.S.C.S.:  Dr. Escamilla has given approximately 100 scientific and professional presentations both at national and international conferences.

Susan A. Chinworth, P.T., Ph.D.:  Dr. Chinworth has given numerous presentations at physical therapy and sports medicine related conferences.