by Dr. Phil on September 24, 2012
Patellofemoral pain syndrome (also known as anterior knee pain) is characterized by pain around the kneecap that increases with prolonged activity or prolonged sitting. It is more common in females and is associated with weakness of the hip, particularly hip abductors, extensors and rotators (Prins et al. 2009) as Dr. Janda had proposed. This weakness is thought to lead to biomechanical deficits at the knee, most notably an increased knee abduction torque, which may alter patellar alignment over the distal femur at the knee. In addition, researchers (Leetun et al. 2004) have found that athletes with weak hip abductors and extensors in pre-participation screenings are more likely to be injured.
Therapeutic exercise programs strengthening the ‘proximal’ musculature (hip and core) have been successful in relieving symptoms of anterior knee pain. A research article in the American Journal of Sports Medicine reported on the outcomes of an exercise program in a series of young females with patellofemoral pain syndrome. After the 8-week exercise program, 17 out of 19 (89%) of the participants had successful outcomes. They had significant improvements in pain, functional ability, core endurance, and hip strength, as well as improvement in the knee abduction angle during gait. The main limitation of this study was the lack of a true control group, which would be able to identify if the exercise program was responsible for the improvements observed.
It would have been beneficial if the authors had identified specific muscle imbalance patterns within the individuals and prescribe an individualized program. In the current study, all participants performed the same exercises regardless of the presence of muscle imbalance. Such information would be helpful in determining if an individualized therapeutic exercise program can be more efficient and effective by targeting specific impairments.
Females with patellofemoral pain syndrome can benefit from a proximal strengthening program. A true control group and long-term follow-up would have been beneficial in further validating the efficacy of the program.
REFERENCE: Earl JE, Hoch AZ. A proximal strengthening program improves pain, function, and biomechanics in women with patellofemoral pain syndrome. Am J Sports Med. 2011 Jan;39(1):154-63. Epub 2010 Oct 7.
by Dr. Phil on September 20, 2012
Dr. Janda often prescribed sensorimotor training exercises using unstable surfaces for patients with chronic low back pain. Dr. Janda considered unstable surfaces such as balance boards as important tools in rehabilitation of chronic musculoskeletal pain syndromes. His Sensorimotor Training program utilizes unstable surfaces can help facilitate automatic postural reactions, which are not possible through voluntary muscle strengthening exercises. It’s important that patients perform sensorimotor training exercises at a level of challenge that allows them to maintain postural stability. Therefore, clinicians must prescribe the appropriate level of instability challenge in each patient for a particular exercise.
Researchers compared muscle activation patterns in patients with low back pain with healthy subjects. They measured trunk muscle activity, lumbar range of motion, and balance during 5 common lumbar stabilization exercises performed on stable and unstable surfaces using an inflatable disk: quadruped, side bridge, modified push-up, squat, and shoulder flexion.
They found that patients with low back pain had adaptive recruitment patterns while maintaining similar levels of balance and lumbar range of motion compared to healthy subjects. There was little increase in electromyographic (EMG) activation among low back pain patients between the stable and unstable surface, and some exercises actually increased lumbar range of motion on unstable surfaces, which is not desirable during lumbar stabilization exercise. Based on these findings, the researchers questioned the need and benefit for using labile surfaces in patients with low back pain.
Subjects in this study may have performed exercises at a level beyond their control, which was evident in the researchers finding increased movement of the lumbar spine on unstable surfaces. All exercises in this study were performed on the same high level of instability, an inflatable disk, which exceeds the challenge recommended by Dr. Janda using balance boards.
It’s also important to note that the researchers only investigated superficial abdominal and low back muscles. Unstable surfaces are thought to activate deeper stabilizing muscles, which is the reason clinicians use them when rehabilitating spine patients. It’s quite possible that deeper muscles were activated in this study because the lumbar spine was shown to move without increased activation of the superficial muscles.
Based on the results of this study, clinicians need to provide an appropriate level of instability to ensure the lumbar spine remains stable during the exercise.
REFERENCE: Desai I, Marshall PW. Acute effect of labile surfaces during core stability exercises in people with and without low back pain. J Electromyogr Kinesiol. 2010 Dec;20(6):1155-62.
