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A Review of Open and Closed Kinetic Chain Exercise Following Anterior Cruciate Ligament Reconstruction
By Anthony C. Miller

The following article has been reproduced by kind permission of the author, Tony Miller. The article is an abstract on a review of open and closed kinetic chain exercise following anterior cruciate ligament reconstruction that formed part of his submitted thesis for his masters degree. Tony studied at the Midwestern State University, completing his Master's of Science in Kinesiology in 1999. As a graduate student, he was able to study under Dr. Lon Kilgore, one of USA's most respected strength coaches.


Over the past ten years there has been a steady argument from physicians, therapists, and coaches over which form of kinetic exercise is most beneficial following anterior cruciate ligament (5) (ACL) reconstruction (Fig. 1).

Figure 1 - Anatomy of the Knee

Figure 1 - Anatomy of a knee

Some of the therapists tend to agree that open kinetic chain exercise (OKCE) benefits the ACL the best. While some therapist believe that closed kinetic chain exercise (CKCE) are superior to OKCE. Recently, ACL ruptures have become the most common knee injury involved in the world of sports. There are approximately 250,000 ACL injuries in a given year (2). These injuries occur due to shear force placed on the ligament during any type of decelerating, turning, planting and cutting, and different types of landings. The ACL can only withstand 400 pounds of pressure at any given time, injuries become more common in high impact sports (10). With injuries becoming more frequent, rehabilitation is becoming more important. The purpose of this review was to determine which form of kinetic chain exercise, open or closed, is most beneficial following ACL reconstruction. We analysed the areas that are most crucial during rehabilitation, strain, stability, joint force, the range of motion (ROM), and strength. We believe that following ACL reconstruction, the safest Kinetic Chain Exercise will decrease stress, strain, and an increase in stability as well as a range of motion (11)

Kinetic Chain Exercises

During any exercise regiment, whether for rehabilitation purposes or for strengthening purposes, there are two types of Kinetic Chain Exercises used. The first is Open Kinetic Chain Exercises (OKCE). These exercises are performed typically were the foot is free to move. These exercises are typically non-weight bearing, with the movement occurring at the knee joint (4). If there is any weight applied, it is applied to the distal portion of the limb. Examples of these exercises would be knee extensions and straight leg raises. OKCE concentrates on a strong quadricep contraction, which will strengthen the quadriceps and restore quadricep power output (8).

The second exercise used is Closed Kinetic Chain Exercise (CKCE). CKCE are performed where the foot is fixed and cannot move. The foot remains in constant contact with the surface, usually the ground or the base of a machine (8). These exercises are typically weight-bearing exercises, where an athlete or patient uses their own body weight and/ or external weight. When external weight is added, it is usually rested across the back of the shoulders or the front of the chest. Examples of these exercises would be the Squat (both front and back), Leg Press, Lung, Power Clean, and Snatch. CKCE concentrates on a co-contraction of the quadriceps, hamstrings, hip flexors, soleus, and gastrocnemius muscles (9). In addition, this is a multi-joint movement, which focuses on the knee, hip, and ankle. CKCE are labelled as being "sport specific movements" (11).

External Forces

During Kinetic Exercises, there are typically two kinds of external forces: shear and compression. Figures 2 and 3 give examples of each type of force. Figure 2 shows the angles of the shear force placed on the knee joint during OKCE and CKCE. Figure 3 shows the ACL with shear and compression forces placed upon it (6).

Figure 2 - Shear force during kinetic exercises

Figure 2 - Shear forces in kinetic exercises

Shear force is the force which causes a disruption of the ACL by shifting the tibia anteriorly and the femur posteriorly. This is caused by the strong contraction of the quadriceps, which is typical of the Open Chain Exercise. This force, which is placed on the front of the knee, places a large amount of stress on the ACL.

The compression force is caused by a strong external force placed on the knee, which pushes the head of the femur together with the head of the tibia. This external force causes stability in the knee and a decrease in shear force. Compression forces are common in Closed Chain Exercises (3, 6).

Review of Literature

Following ACL reconstruction, the rehabilitation is the most important aspect of restoring the knee joint back to normal levels of competition. Over the past decade, there have been a number of studies that focus on the rehabilitation of the ACL (5). Due to the extensive research in this field, there are still differences in opinions among many people involved in the athletic community (11).

Koch (6), in a popular magazine essay, states CKCE produces a minimal amount of shear force, while OKCE produces a great amount of shear force. When the knee is extended during Kinetic Chain Exercises, there is a strong contraction of the quadriceps. Koch found that with CKCE there is a co-contraction of the quadriceps and hamstrings (6). This reduces shear force placed on the knee by stabilizing the knee joint. Opposing to OKCE which increases shear force on the knee joint. This is caused by the lower leg shifting anteriorly which places a significant amount of stress on the ACL (Fig.'s 2 & 3).

Figure 3 - Joint Forces

Figure 3 - Joint Forces

Previous research performed comparing OKCE and CKCE found that CKCE was a safer and more beneficial form of exercise. Pincivero et al. (12) found that CKCE reduced the shear force and increased compression force in the knee joint (Fig. 3). Also, they found that CKCE activated the hamstrings, which increase knee stability. This occurs because, with the contraction of the hamstrings, the quadriceps are neutralized by pulling the tibia forward, which decrease anterior tibial displacement (3).

Escamilla et al. (3) found that there was a large amount of quadricep activity during both exercises (quadricep contraction causes anterior tibial displacement). They found that strain placed on the ACL during exercise is directly related to the shear force placed on the knee joint (3). When shear force is decreased this leads to a decrease in anterior tibial displacement. During CKCE the hamstrings are contracted, which reduces anterior tibial displacement. These results are similar to Jenkins et al.'s study (5). This study found that OKCE increases the anterior displacement of the tibia. In addition, shear force is increased with OKCE.

In 1997 Fitzgerald (4) found that there were no significant differences between OKCE and CKCE. In this study, Fitzgerald believes there is a place for both kinetic exercises during ACL rehabilitation.


Rehabilitation is the most important stage following ACL rupture. It is very important to understand what each form of kinetic exercise does to the knee joint (1). As coaches, trainers, physicians, and therapists we must understand the strain, joint forces (Fig. 3), and torque placed on the knee during each exercise. Also, we must acknowledge which exercises, cause stability, an increase in compression force, as well as increased ROM, which will benefit the patient during rehabilitation.

The most important aspect is to return the athlete back to pre-injury competition level, as safe as possible (11). In order to do this, we must utilize the exercises that will prevent re-injuring the repaired ACL. This review of the literature found that Closed Kinetic Chain Exercises are the most beneficial during rehabilitation of the repaired ACL. Also, CKCE is the most beneficial exercises used for the prevention of future injuries of the knee joint (5, 6, 7).


We believe that there needs to be more research, which focuses mainly on comparing OKCE and CKCE. Of the studies found, only one study that supported OKCE and only one found that there were no significant differences between OKCE and CKCE. The rest of the studies concentrated on advantages and/ or disadvantages of either one Kinetic Chain Exercise or the other. There were only a few articles, which compared directly Open and Closed Kinetic Chain Exercises


  • Figure 1. Aichroth PM, Cannon WD, Amis AA, Mahadevan V, Bull AJ, & Harris JM. "The Interactive Knee." Primal Pictures, Ltd. 1998
  • Figures 2 & 3. Koch, A. Leg extensions: are they destroying your knees. Muscular Development: 100-103, June 1999
  1. Jenkins, et al. A measurement of anterior tibial displacement in closed and open kinetic chain. JOSPT, 25(1): 49-56, 1997
  2. Clasby, L & Young MA. Management of sports-related anterior cruciate ligament injuries. AORN
  3. Russell, et al. Knee muscle strength in elite male gymnasts. JOSPT, 22(1): 10-17, 1995.
  4. Shelbourne, KD & Nitz, P. Accelerated rehabilitation after anterior cruciate ligament reconstruction. The American Journal of Sports Medicine, 18(3): 292-299, 1990
  5. Escamilla, et al. Biomechanics of the knee during closed kinetic chain and open kinetic chain exercises. Medicine and Science in Sports and Exercise Science: 556-569, 1998
  6. Koch, A. Leg extensions: are they destroying your knees. Muscular Development: 100-103, June 1999.
  7. Palmitier, et al. Kinetic chain exercises in knee rehabilitation. Sports Medicine, 11(6): 402-413, 1991
  8. Anderson, AF & Lipscomb AB. Analysis of rehabilitation techniques after anterior cruciate reconstruction. The American Journal of Sports Medicine, 17(2): 154-160, 1989.
  9. Fitzgerald, GK. Open versus closed chain kinetic exercise: issues in rehabilitation after anterior cruciate ligament reconstructive surgery. Physical Therapy, 77(12): 1747-1754, 1997.
  10. Nisell, R. Mechanics of the Knee: a study of joint and muscle load with clinical applications. ACTA Orthopaedic Scandinavica Supplementum, 216(56): 1-42, 1985.
  11. Lander, et al. Biomechanics of the squat exercise using a modified center of mass bar. Medicine and Science in Sports and Exercise: 469-478, March 1986
  12. Pincivero, et al. Relation between open and closed kinematic chain assessment of knee strength and functional performance. Clinical Journal of Sports Medicine, 7: 11-16, 1997.

Related References

The following references provide additional information on this topic:

  • HAN, H. S. et al. (2008) Anterior cruciate ligament reconstruction. Clinical orthopaedics and related research466 (1), p. 198-204
  • SHELBOURNE, K. D. and NITZ, P. (1990) Accelerated rehabilitation after anterior cruciate ligament reconstruction. The American journal of sports medicine, 18 (3), p. 292-299
  • YAGI, M. et al. (2002) Biomechanical analysis of an anatomic anterior cruciate ligament reconstruction. The American Journal of Sports Medicine30 (5), p. 660-666

Page Reference

If you quote information from this page in your work, then the reference for this page is:

  • MACKENZIE, B. (2000) A Review of Open and Closed Kinetic Chain Exercise Following Anterior Cruciate Ligament Reconstruction [WWW] Available from: [Accessed

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