Increased Risk Of Knee Injury Research Articles

Kinematic differences during a jump cut maneuver between individuals with and without a concussion history.

Recent evidence suggests that athletes are at a higher risk of lower-body injuries in the months and years following a concussion. However, little is known about how people modify their movements post-concussion. This study examined kinematics during a jump cut motion in young adults with a concussion history (n=9; 4 males, 5 females; 3.1years' post-injury) and 10 controls (6 males, 4 females). Peak center of mass and peak knee angles during the landing phase of a jump-cut maneuver were evaluated. Participants with a concussion history demonstrated decreased knee varus (left: Mconc=-0.5±1.0°, Mctrl=3.6±1.0°; right: Mconc=5.1±1.2°, Mctrl=7.8±1.12°) and external rotation (left: Mconc=2.5±1.6°, Mctrl=13.0±1.5°; right: Mconc=7.7±1.6°, Mctrl=12.8±1.5°) regardless of whether the cut was oriented towards to the left or right. The kinematic patterns demonstrated in individuals with a concussion history may be suggestive of increased knee injury risk. This study adds to the growing body of literature linking orthopedic injury in those no longer displaying the acute signs and symptoms of concussion.

The association of dorsiflexion flexibility on knee kinematics and kinetics during a drop vertical jump in healthy female athletes.

While previous studies have examined the association between ankle dorsiflexion flexibility and deleterious landing postures, it is not currently known how landing kinetics are influenced by ankle dorsiflexion flexibility. The purpose of this study was to examine whether ankle dorsiflexion flexibility was associated with landing kinematics and kinetics that have been shown to increase the risk of anterior cruciate ligament (ACL) injury in female athletes. Twenty-three female collegiate soccer players participated in a preseason screening that included the assessment of ankle dorsiflexion flexibility and lower-body kinematics and kinetics during a drop vertical jump task. The results demonstrated that females with less ankle dorsiflexion flexibility exhibited greater peak knee abduction moments (r = -.442), greater peak knee abduction angles (r = .355), and less peak knee flexion angles (r = .385) during landing. The range of dorsiflexion flexibility for the current study was between 9° and 23° (mean = 15.0°; SD 3.9°). Dorsiflexion flexibility may serve as a useful clinical measure to predict poor landing postures and external forces that have been associated with increased knee injury risk. Rehabilitation specialists can provide interventions aimed at improving dorsiflexion flexibility in order to ameliorate the impact of this modifiable factor on deleterious landing kinematics and kinetics in female athletes. II.

Anticipatory postural adjustments during cutting manoeuvres in football and their consequences for knee injury risk

Anticipatory postural adjustments (APAs), i.e. preparatory positioning of the head, the trunk and the foot, are essential to initiate cutting manoeuvres during football games. The aim of the present study was to determine how APA strategies during cutting manoeuvres are influenced by a reduction of the time available to prepare the movement.Thirteen football players performed different cutting tasks, with directions of cutting either known prior to the task or indicated by a light signal occurring 850, 600 or 500 ms before ground contact.With less time available to prepare the cutting manoeuvre, the head was less orientated towards the cutting direction (P = 0.033) and the trunk was even more rotated in the opposite direction (P = 0.002), while the foot placement was not significantly influenced. Moreover, the induced higher lateral trunk flexion correlated with the increased knee abduction moment (r = 0.41; P = 0.009).Increasing lateral trunk flexion is the main strategy used to successfully perform a cutting manoeuvre when less time is available to prepare the movement. However, higher lateral trunk flexion was associated with an increased knee abduction moment and therefore an increased knee injury risk. Reducing lateral trunk flexion during cutting manoeuvres should be part of training programs seeking the optimisation of APAs.

A comparison between the star excursion balance test and subjective assessment of knee stability in a single-leg squat

BackgroundExcessive dynamic knee valgus may leave athletes prone to serious knee injuries. The Star Excursion Balance Test (StarReach) is an objective clinical test, well applicable for non-clinicians, to identify athletes...

Knee Valgus Angle During Landing Tasks in Female Volleyball and Basketball Players

Increased knee valgus angles have been associated with an increased risk of a variety of knee injuries. It has yet to be established if knee valgus angles during jump landing tasks differ between jumping sports with relatively higher and lower knee injury rates-namely, basketball and volleyball. Any difference in knee angles on landing may be related to sport-specific differences, which may in turn relate to the different injury risk rates. Fifteen elite female basketball and volleyball players had their knee valgus angles assessed during 2 landing tasks: 1 bilateral (drop jump landing) and 1 unilateral (step landing task). During the drop jump task knee valgus angle was significantly greater in the basketball group (p = 0.017) in the right knee, but there was no significant difference in performance between sports in the left knee (p = 0.67). During the step landing task volleyball players had significantly greater knee valgus angles than basketball players for both the left (p = 0.018) and right (p = 0.025) knees. The basketball group showed superior control of knee valgus during the unilateral task, which may be related to sport-specific skills. The basketball players showed significant asymmetry in knee valgus angle during bilateral drop jump landings; this finding reflects those of previous studies and may be related to the relative increased knee injury risk reported for this population group.

Electromyography of the thigh muscles during lifting tasks in kneeling and squatting postures

Underground coal miners who work in low-seam mines frequently handle materials in kneeling or squatting postures. To assess quadriceps and hamstring muscle demands in these postures, nine participants performed lateral load transfers in kneeling and squatting postures, during which electromyographic (EMG) data were collected. EMG activity was obtained at five points throughout the transfer for three quadriceps muscles and two hamstring muscles from each thigh. ANOVA results indicated that EMG data for nine of 10 thigh muscles were affected by an interaction between posture and angular position of the load lifted (p < 0.001). Muscles of the right thigh were most active during the lifting portion of the task (lifting a block from the participant's right) and activity decreased as the block was transferred to the left. Left thigh muscles showed the opposite pattern. EMG activity for the majority of thigh muscles was affected by the size of the base of support provided by different postures, with lower EMG activity observed with a larger base of support and increased activity in postures where base of support was reduced (p < 0.05). Thigh EMG activity was lowest in postures with fully flexed knees, which may explain worker preference for this posture. However, such postures are also associated with increased risk of meniscal damage. Statement of Relevance:Kneeling and squatting postures are sometimes used for manual lifting activities, but are associated with increased knee injury risk. This paper examines the EMG responses of knee extensors/flexors to lifting in these postures, discusses the impact of posture and kneepads on muscle recruitment and explores the implications for work in such postures.

Deficits in Neuromuscular Control of the Trunk Predict Knee Injury Risk

Background Female athletes are at significantly greater risk of anterior cruciate ligament (ACL) injury than male athletes in the same high-risk sports. Decreased trunk (core) neuromuscular control may compromise dynamic knee stability. Hypotheses (1) Increased trunk displacement after sudden force release would be associated with increased knee injury risk; (2) coronal (lateral), not sagittal, plane displacement would be the strongest predictor of knee ligament injury; (3) logistic regression of factors related to core stability would accurately predict knee, ligament, and ACL injury risk; and (4) the predictive value of these models would differ between genders. Study Design Cohort study (prognosis); Level of evidence, 2. Methods In this study, 277 collegiate athletes (140 female and 137 male) were prospectively tested for trunk displacement after a sudden force release. Analysis of variance and multivariate logistic regression identified predictors of risk in athletes who sustained knee injury. Results Twenty-five athletes (11 female and 14 male) sustained knee injuries over a 3-year period. Trunk displacement was greater in athletes with knee, ligament, and ACL injuries than in uninjured athletes (P < .05). Lateral displacement was the strongest predictor of ligament injury (P = .009). A logistic regression model, consisting of trunk displacements, proprioception, and history of low back pain, predicted knee ligament injury with 91% sensitivity and 68% specificity (P = .001). This model predicted knee, ligament, and ACL injury risk in female athletes with 84%, 89%, and 91% accuracy, but only history of low back pain was a significant predictor of knee ligament injury risk in male athletes. Conclusions Factors related to core stability predicted risk of athletic knee, ligament, and ACL injuries with high sensitivity and moderate specificity in female, but not male, athletes.