It has been said the knee has "no place to hide." Functionally, its fate often is sealed by the foot or hip to which it is linked in the kinetic chain.4 Knee forces have been characterized as "slaved" to the hip.1 There are various sources of biomechanical overload for the knee.
One of the most common is medial collapse of the knee, secondary to either subtalar hyperpronation or frontal-plane hip instability (e.g., trendelenberg position of the pelvis).7,18 A key factor in the lower-quarter kinetic-chain dysfunction is gluteus medius weakness.23 Mascal, et al., have demonstrated that a pelvic drop and excessive knee valgus during a step-down task is indicative of contralateral gluteus medius weakness.17 Ireland, et al., have shown this weakness is common in patients with knee pain.9 Specifically, deficits of 26 percent in hip abduction strength and 36 percent hip external rotation strength were found. Thus, reducing injury rates relies on detecting and continually evaluating people with relatively large valgus motions.18
The female athlete is at greater risk than the male for season-ending knee injury.21 In particular, females with increased dynamic valgus loads are at increased risk of ACL injury.7 Females have a shorter duration of gluteus medius activation in stance, load-absorbing, phase during a cutting maneuver.10
A comparison of male and female healthy collegiate soccer players demonstrated that females experience increased frontal-plane moments and decreased sagittal-plane moments during early deceleration of side-stepping maneuvers.25 This dysfunction in tissue sparing of the knee was termed an "at-risk" pattern in that frontal-plane support of the knee, which could overload the anterior cruciate ligament. It also was noted that females exhibited increased quadriceps activity and smaller net flexor moments, suggesting less sagittal-plane protection (i.e., increased tendency toward anterior tibial translation).
Since biomechanical overload of the knee is so common, the question of prevention arises. Children under seven years of age have been shown to have a predisposition to faulty motor control; in particular, hyperpronation in the foot and angle during gait.2 It is suggested that prepubertal or early pubertal female athletes may benefit from biomechanical optimization by reducing their future lower-extremity injury risk.8
Neuromuscular training has been shown to improve performance and lower-extremity biomechanics in female athletes.6,20,22 Hewett5 has shown in female collegiate athletes that the introduction of supinatory training during plyometric squats prospectively reduced the incidence of injury in the coming season. The four main components of this training are plyometric and movement, core strengthening and balance, resistance training and speed training.20
Gary Gray has pioneered exercises such as balance reaches incorporating the star matrix.3,11-15,19,24 By balancing or supporting on one limb, while reaching at different angles with the other limb, tri-planer movement in the sagittal, frontal and transverse planes can be trained. By adding upper-quarter movements, functional activities involving pushing and pulling such as tennis, baseball, golf and bowling, can be facilitated.
- Bobbert MF, van Zandwijk JP. Dynamics of force and muscle stimulation in human vertical jumping. Med Sci Sports Exerc, 1999;31:303-10.
- Ganley KJ, Powers CM. Gait kinematics and kinetics of 7-year-old children: a comparison to adults using age-specific anthropometric data. Gait & Posture, 2005;21(2):141-5.
- Gray G. Total Body Functional Profile. Adrian, MI: Wynn Marketing, 2001.
- Griffin LY, Agel J, Alborhm MJ, et al. Non-contact anterior cruciate ligament injuries: risk factors and prevention strategies. J Am Acad Orthop Surg, 2000;8:141-50.
- Hewett T, Lindenfeld TN, Roccobene JV, Noyes FR. The effect of neuromuscular training on the incidence of knee injury in female athletes: a prospective study. Am J Sports Med, 1999;27:699-706.
- Hewett TE, Paterno MV, Myer GD. Strategies for enhancing proprioception and neuromuscular control of the knee. Clin Orthop Relat Res, 2002;402:76-94.
- Hewett TE, Myer GD, Ford KR, et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: a prospective study. Am J Sports Med, 2005;33(4):492-501.
- Hewett TE, Myer GD, Ford KR. Reducing knee and anterior cruciate ligament injuries among female athletes: a systematic review of neuromuscular training interventions. J Knee Surg, 2005a;18(1):82-8.
- Ireland ML, Willson JD, Ballantyne BT, McClay-Davis I. Hip strength in females with and without patellofemoral pain. J Orthop Sports Phys Ther, 2004;33:671-6.
- Liebenson CS. Functional problems associated with the knee part one: sources of biomechanical overload. Journal of Bodywork and Movement Therapies, 2006;10(4):306-11.
- Liebenson CS. Advice for the clinician and patient: Functional exercises. Journal of Bodywork and Movement Therapies, 2002;6(2):108-16.
- Liebenson CS. Advice for the clinician and patient: Functional training part one: new advances. Journal of Bodywork and Movement Therapies, 2002a;6(4):248-53.
- Liebenson CS. Advice for the clinician and patient: Functional training part two: integrating functional training into clinical practice. Journal of Bodywork and Movement Therapies, 2003;7(1):20-4.
- Liebenson CS. Advice for the clinician and patient: Functional training part three: transverse plane facilitation. Journal of Bodywork and Movement Therapies, 2003a;7(2):97-103.
- Liebenson CS. Functional training for performance enhancement. Journal of Bodywork and Movement Therapies, 2006;10(2):159-62.
- Liebenson CS. Functional stability training. In: Liebenson C, Ed. Rehabilitation of the Spine: A Practitioner's Manual, 2nd ed. Baltimore: Lippincott/Williams & Wilkins, 2007.
- Mascal CL, Landel R, Powers C. Management of patellofemoral pain targeting hip, pelvis, and trunk muscle function: 2 case reports. J Ortho Sports Phys Ther, 2003;33:647-60.
- McLean SG, Walker K, Ford KR, et al. Evaluation of a two-dimensional analysis method as a screening and evaluation tool for anterior cruciate ligament injury. Br J Sports Med, 2005;39(6):355-62.
- McGill SM. Ultimate Back Fitness and Performance, 2nd ed. Wabunu, 2006.
- Myer GD, Ford KR, Palumbo JP, Hewett TE. Neuromuscular training improves performance and lower-extremity biomechanics in female athletes. J Strength Cond Res, 2005;19(1):51-60.
- Nadler SF, Malanga GA, DePrince ML, et al. The relationship between lower extremity injury, low back pain, and hip muscle strength in male and female collegiate athletes. Clin J Sports Med, 2000;10:89-97.
- Paterno MV, Myer GD, Ford KR, Hewett TE. Neuromuscular training improves single-limb stability in young female athletes. J Orthop Sports Phys Ther, 2004;34(6):305-16.
- Powers CM. The influence of altered lower-extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sports Phys Ther, 2003;33:639-46.
- Risberg MA, Mork M, Krogstad AL, et al. Design and implementation of a neuromuscular training program following anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther, 2001;31:620-31.
- Sigward SM, Powers CM. The influence of gender on knee kinematics, kinetics and muscle activation patterns during side-step cutting. Clin Biomech, 2006;21(1):41-8.
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