Deficits in 'core stability' predict knee injury
It has been hypothesized that ACL and other knee injuries may result from inappropriate dynamic positioning of the knee. Dynamic stability of an athlete’s knee depends on accurate sensory input and appropriate motor responses to meet the demands of rapid changes in trunk position during cutting, stopping, and landing movements. Inadequate neuromuscular control of the body’s trunk or “core” may compromise this lower extremity dynamic stability, resulting in increased torque and valgus collapse at the knee, which may increase strain on the knee ligaments and lead to injury. It is known that core muscle activity should precede lower extremity muscle activity in the temporal sequence of many athletic tasks, while a history of low back pain is known to alter neuromuscular control of such muscles. Such deficiencies may predispose athletes to low back injuries as well as injuries of the lower extremity A recent study published in the American Journal of Sports Medicine by Zazulak and co-workers has demonstrated that factors related to core stability do in fact predict knee, ligament, and ACL injury risk in athletes. Athletes were tested at baseline for a variety of neuromuscular deficiencies and then followed for 3 years to track all knee, knee ligament and/or ACL injuries sustained. Two hundred and seventy seven athletes were tested at baseline and all ligament and meniscal injuries were confirmed by magnetic resonance imaging. Results of the study found that trunk displacement (a measure of core stability) were significantly greater in knee injured, knee ligament–injured, and ACL-injured athletes compared with uninjured athletes. A history of low back pain produced a 6X increased risk of knee in injury in females, and a 10X greater risk of ACL injury in males. Furthermore it was found that a combination of factors related to core stability (increased trunk displacement in all 3 measured directions, absolute error in repositioning, and history of low back pain) significantly predicted knee injury with 83% sensitivity and 63% specificity. The strongest predictors of injury in the female athletes were the displacement variables. Active proprioceptive repositioning error and history of LBP were also predictors of knee injury. In the male injured group, the model only reached statistical significance for the ligament-injured subjects, for whom history of LBP was the strongest predictor of injury. The study conducted demonstrates that factors related to core stability predict knee, ligament, and ACL injury risk in athletes. The authors state that decreased neuromuscular control of the trunk appears to influence dynamic stability of the knee joint and to increase knee injury risk during high-speed athletic manoeuvres. High ground-reaction forces directed toward the body’s centre of mass, coupled with decreased trunk neuromuscular control, may compromise dynamic stability of the knee. The results suggest that the implementation of interventions that incorporate core stability training, including proprioceptive exercise, perturbation, and correction of body sway, have the potential to reduce knee, ligament, and ACL injury risk in both female and male athletes. However, future research is required to assess the efficacy of interventions in producing change in core stability and to investigate whether this does in fact result in injury prevention. The relationship between dysfunction in trunk neuromuscular control should also be investigated for other lower limb injuries, including hamstring muscle strains as has previously been suggested in the literature (Hoskins & Pollard, Manual Therapy 2005). Zazulak BT, Hewett TE, Reeves NP, Goldberg B, Cholewicki J. Deficits in Neuromuscular Control of the Trunk Predict Knee Injury Risk: A Prospective Biomechanical-Epidemiologic Study. Am J Sports Med. 2007
It has been hypothesized that ACL and other knee injuries may result from inappropriate dynamic positioning of the knee. Dynamic stability of an athlete’s knee depends on accurate sensory input and appropriate motor responses to meet the demands of rapid changes in trunk position during cutting, stopping, and landing movements. Inadequate neuromuscular control of the body’s trunk or “core” may compromise this lower extremity dynamic stability, resulting in increased torque and valgus collapse at the knee, which may increase strain on the knee ligaments and lead to injury. It is known that core muscle activity should precede lower extremity muscle activity in the temporal sequence of many athletic tasks, while a history of low back pain is known to alter neuromuscular control of such muscles. Such deficiencies may predispose athletes to low back injuries as well as injuries of the lower extremity A recent study published in the American Journal of Sports Medicine by Zazulak and co-workers has demonstrated that factors related to core stability do in fact predict knee, ligament, and ACL injury risk in athletes. Athletes were tested at baseline for a variety of neuromuscular deficiencies and then followed for 3 years to track all knee, knee ligament and/or ACL injuries sustained. Two hundred and seventy seven athletes were tested at baseline and all ligament and meniscal injuries were confirmed by magnetic resonance imaging. Results of the study found that trunk displacement (a measure of core stability) were significantly greater in knee injured, knee ligament–injured, and ACL-injured athletes compared with uninjured athletes. A history of low back pain produced a 6X increased risk of knee in injury in females, and a 10X greater risk of ACL injury in males. Furthermore it was found that a combination of factors related to core stability (increased trunk displacement in all 3 measured directions, absolute error in repositioning, and history of low back pain) significantly predicted knee injury with 83% sensitivity and 63% specificity. The strongest predictors of injury in the female athletes were the displacement variables. Active proprioceptive repositioning error and history of LBP were also predictors of knee injury. In the male injured group, the model only reached statistical significance for the ligament-injured subjects, for whom history of LBP was the strongest predictor of injury. The study conducted demonstrates that factors related to core stability predict knee, ligament, and ACL injury risk in athletes. The authors state that decreased neuromuscular control of the trunk appears to influence dynamic stability of the knee joint and to increase knee injury risk during high-speed athletic manoeuvres. High ground-reaction forces directed toward the body’s centre of mass, coupled with decreased trunk neuromuscular control, may compromise dynamic stability of the knee. The results suggest that the implementation of interventions that incorporate core stability training, including proprioceptive exercise, perturbation, and correction of body sway, have the potential to reduce knee, ligament, and ACL injury risk in both female and male athletes. However, future research is required to assess the efficacy of interventions in producing change in core stability and to investigate whether this does in fact result in injury prevention. The relationship between dysfunction in trunk neuromuscular control should also be investigated for other lower limb injuries, including hamstring muscle strains as has previously been suggested in the literature (Hoskins & Pollard, Manual Therapy 2005). Zazulak BT, Hewett TE, Reeves NP, Goldberg B, Cholewicki J. Deficits in Neuromuscular Control of the Trunk Predict Knee Injury Risk: A Prospective Biomechanical-Epidemiologic Study. Am J Sports Med. 2007