ArticleLiterature Review

The relationship between hip muscle strength and dynamic knee valgus in asymptomatic females: A systematic review

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Abstract

Objective: To systematically review literature investigating the relationship between hip muscle strength and dynamic lower extremity valgus during movement tasks in asymptomatic females. Methods: Four databases (CINAHL, SPORTDiscus, Embase and Ovid MEDLINE) were searched in February 2017. Studies investigating the relationship between hip muscle strength and dynamic knee or lower extremity valgus during movement tasks among asymptomatic females over 18 years old were included. Meta-analyses were performed where two or more studies used similar tasks. Results: Five studies reported no relationship between hip strength and dynamic lower extremity valgus. Greater peak lower extremity valgus was associated with reduced hip strength in eight studies, and greater hip strength in three studies. In the meta-analysis, a relationship between weaker hip strength and greater dynamic lower extremity valgus was found for ballistic single leg landing, but not double leg landing or single leg squat tasks. Conclusions: Although the relationship between hip strength and dynamic lower extremity valgus is conflicting, meta-analysis revealed lower extremity dynamic valgus was consistently associated with hip strength in single leg ballistic tasks, but not double leg ballistic or single leg squat tasks. The relationship between hip strength and dynamic lower extremity valgus may be conditional to task demand.

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... Based on this chain, one of the contributing factors in the development of poor lower extremity kinematics and faulty movement pattern is the dysfunction of the hip abductor and external rotator muscles [16][17][18]. During functional activity especially single-leg activity such as walking, running, or stair climbing, in healthy subjects, DKV is associated with hip muscle strength [19]. In this activity, the external moments acting on the hip cause the femur to adduct, internally rotate, and force the knee to medial displacement [20]. ...
... The results provide level 1b or moderate evidence that prescribing hip muscle strengthening intervention may improve knee valgus angle, hip flexion angle, knee rotation angle, hip adduction angle, and contralateral pelvic drop angle, and four "fair" quality studies indicate that prescribing hip muscle strengthening exercise cannot improve lower extremity kinematics. The result of the current review agrees with the results of previously published studies, which mentioned that the relationship between hip muscle strength and lower extremity strength is conflicting [19,37] It is suggested that greater hip muscle strength may improve better dynamic control of the femur and/or pelvis during a functional task [19,38]. Hip kinematic patterns in the motions planes occur in opposite directions. ...
... The results provide level 1b or moderate evidence that prescribing hip muscle strengthening intervention may improve knee valgus angle, hip flexion angle, knee rotation angle, hip adduction angle, and contralateral pelvic drop angle, and four "fair" quality studies indicate that prescribing hip muscle strengthening exercise cannot improve lower extremity kinematics. The result of the current review agrees with the results of previously published studies, which mentioned that the relationship between hip muscle strength and lower extremity strength is conflicting [19,37] It is suggested that greater hip muscle strength may improve better dynamic control of the femur and/or pelvis during a functional task [19,38]. Hip kinematic patterns in the motions planes occur in opposite directions. ...
Article
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Purpose Poor lower extremity kinematics have been linked with lower extremity injuries. One of the main contributing factors in the development of poor lower extremity kinematics is hip muscle weaknesses. This systematic review aimed to summarize the literature related to the effects of hip muscle strengthening on lower extremity kinematics among healthy subjects. Methods A search for randomized controlled trials (RCTs) was conducted using the following databases: Cochrane, Web of Science, MEDLINE, PEDro and EBSCO. The selected studies had to distinguish the effects of hip muscle strengthening in healthy subjects, as compared to non-intervention or other kinds of intervention, and investigate at least one of the lower extremity kinematic factors. Two researchers performed study screening for obtaining the quality assessment scores in each included study using the PEDro scale. Statistical heterogeneity was tested using the Chi² test and I² statistic. Results Five studies were entered to review. There was level 1b or moderate evidence based on one “high” quality study that demonstrated hip muscle strengthening intervention was effective in the improvement of lower extremity kinematics. Conclusion It is difficult to make any definitive conclusions based on the results of this review and further research is needed. However, it should be considered that prescription hip muscle strengthening interventions alone maybe has a small effect on lower extremity kinematics in healthy subjects.
... Poor sagittal and frontal plane movement patterns are believed to increase knee injury risk in athletes [10,25]. Specifically, dynamic malalignment patterns comprised of greater ipsilateral trunk lean, hip adduction, hip internal rotation, knee valgus (KV) and tibial internal or external rotation, in addition to less hip and knee flexion, have been associated with greater knee joint loading and subsequently higher non-contact ACL injury risk during landing tasks. ...
... Characterized by an erect landing posture and less sagittal plane trunk displacement, stiff landings result in greater ground reaction forces [12], external knee abduction and flexion moments, and smaller Sheikhi et al. J EXP ORTOP (2021) 8:25 external hip flexion moments [8,10]. In the sagittal plane, the trunk and lower extremity work in a coupled fashion to attenuate landing forces, such that greater motion at one joint is typically accompanied by corresponding motion at adjacent joints, allowing for improved force absorption [9,12]. ...
... Increased lateral trunk lean causes the ground reaction vector to pass lateral to the knee joint, thereby creating an external knee abduction moment. Greater KV allows the ground reaction force (GRF) to exert even greater frontal plane torque upon the knee joint [8,10]. In addition to intra-limb kinematics, inter-limb asymmetries are also shown to increase the occurrence of sport-related injuries. ...
Article
Purpose: The purpose of the study was to investigate the influence of a 72-h KT application on trunk and lower extremity kinematics during different landing tasks. Methods: Twenty-nine competitive male athletes participated in this study. The sum of knee valgus and lateral trunk lean, symmetry index (SI), and peak angles of lateral trunk lean, hip flexion, knee abduction and flexion were assessed for all participants during single-leg drop landing (SLDL), single-leg vertical drop jump (SLVDJ), vertical drop jump (DLVDJ), and double leg forward jump (DLFJ), at baseline and seventy-two hours following KT application. Results: The KT application resulted in more knee flexion and abduction, sum of knee valgus and lateral trunk lean as compared with the non-KT condition during SLDL (P < 0.05). Nonetheless, there were no differences in SI, maximum angle of the lateral trunk lean during SLDL, SLVDJ, nor hip flexion, knee abduction, and flexion during DLVDJ, and DLFJ tasks (P > 0.05). Conclusions: The research findings suggest that KT after 72-h application may improve knee abduction and sum of knee valgus and lateral trunk lean during SLDL, knee flexion during SLDL and SLVDJ in individuals displaying risky single-leg kinematics. Therefore, KT application may marginally improve high-risk landing kinematics in competitive male athletes. Level of evidence: Level III. Keywords: Anterior cruciate ligament; Joint kinematics; Kinesio tape; Knee; Landing.
... A substantial body of research has investigated the relationship between hip muscle strength and dynamic knee valgus (DKV). Two similar reviews have investigated the relationship and established limited evidence, alongside conflicting findings among studies [10,11]. The review by Cashman [10] failed to reach a definitive conclusion, primarily due to the variation in methodology and lack of consensus among the studies considered for the review. ...
... As such, new knowledge has emerged regarding recent studies that have been undertaken. Another meta-analysis published by Dix et al. [11] established that a reduction in the strength of hip extensors, external rotators, and abductors is associated with the DKV during single-leg drop landings, but not double-leg landing. They suggested that the distinction in the results of the kinematic evaluation of the lower limbs between single-and double-leg tasks is largely due to varying demands and muscle recruitments that require significant eccentric work to provide control in the frontal plane angles. ...
... Including injured participants could confound the association between hip muscle strength and DKV because injuries and pain (e.g., knee osteoarthritis, patellofemoral pain, and some other lower extremity injuries) can cause DKV [12][13][14]; therefore, studies are not able to differentiate whether muscle weakness is the cause of the DKV or whether it occurs due to some mechanism of compensation or inhibition by the body in response to injury or pain. Furthermore, the review by Dix et al. [11] included studies that only utilized three-dimensional (3D) motion analysis in the measurement. It is worth noting that the two-dimensional (2D) motion system, however, has been proven to be an easier and more clinically accessible and applicable motion analysis approach compared to the 3D system, which requires expensive and laboratory-based procedures [15]. ...
Article
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This study aimed to systematically review research investigating the association between hip muscle strength and dynamic knee valgus (DKV). Four databases (MEDLINE, PubMed, CINAHL, and SPORTDiscus) were searched for journal articles published from inception to October 2020. Seven studies investigating the association between hip muscle strength and DKV using a two-dimensional motion analysis system in healthy adults were included. The relationship between hip abductor muscle strength and DKV was negatively correlated in two studies, positively correlated in two studies, and not correlated in three studies. The DKV was associated with reduced hip extensor muscle strength in two studies and reduced hip external rotator muscle strength in two studies, while no correlation was found in three and five studies for each muscle group, respectively. The relationship between hip muscle strength, including abductors, extensors, and external rotators and DKV is conflicting. Considering the current literature limitations and variable methodological approaches used among studies, the clinical relevance of such findings should be interpreted cautiously. Therefore, future studies are recommended to measure the eccentric strength of hip muscles, resembling muscular movement during landing. Furthermore, high-demand and sufficiently challenging functional tasks revealing lower limb kinematic differences, such as cutting and jumping tasks, are recommended for measuring the DKV.
... Among others, neuromuscular control of the hip musculature is one of the essential factors in affording proximal stability for distal segment motion (Chuter and de Jonge 2012). Previous studies declared alteration in hip muscle function can lead to the poor lower extremity kinematics such as DKV (Dix et al., 2019;Stickler et al., 2015;Ugalde et al., 2015). ...
... Thus changes in LEAM may result to changes in the force and activation production characteristics of the hip muscle. For example, coupling mechanism states foot pronation leads to internal tibial rotation and femoral internal rotation causing a position which is proposed to creating a valgus position, and this conditions changed pelvis position, that is suggested this change can increased strain on hip and pelvis muscles (Dix et al., 2019). Although it is assumed that change in LEAM potentially by altering the length, tension, and orientation characteristics of the muscles and their final torque-producing cabilities can contribute to creating DKV, whether each of single parameters of LEAM that can contribute in DKV predicting is unclear. ...
Article
Introduction Dynamic knee valgus (DKV) is a risk factor for lower extremity injuries such as anterior cruciate ligament and patellofemoral pain syndrome. Purpose of the current study was to investigate the relationship between lower extremity anatomical measures (LEAM) and core stability with DKV during the single-leg squat. Methods Thirty healthy men aged between 18 and 28 years participated in this cross-sectional biomechanical study.DKV was assessed using a 6-camera motion analysis system during a single-leg squat task. Anteversion of hip, hip internal and external rotation, Q-angle, knee hyperextension, tibial torsion, tibia vara, plantar arch index, and core stability were measured using standard clinical procedures. To predict DKV, a multiple linear regression model was used. Result The stability index negatively and plantar arch index positively predicted greater DKV during the single-leg squat task (P= 0.001 and P= 0.09, respectively). Research variables together predicted 82% of the variance in DKV (F(4,26)= 28.09, p<0.001). However, relationships between other variables and DKV were not found. Conclusion The core stability index and plantar arch index were associated with observed DKV during the single-leg squat. These results suggested that proximal and distal variables to the knee should be considered when evaluating individuals who present DKV during the single-leg squat.
... To assess the concurrent validity between the gluteus medius clinical test and a maximum isometric force test of the hip abductors using the hand-held dynamometer; (2) to determine the intra and inter-examiner reliability for the application of the gluteus medius clinical test; and (3) to describe reference values of gluteus medius clinical test on a population of youth athletes. ...
... The hip abductor muscles, mainly the gluteus medius (GM), are responsible for controlling hip adduction in closed kinetic chain, 1 and are associated with preventing dynamic knee valgus during the single leg squat. 2 Dynamic knee valgus can result in injuries, such as anterior cruciate ligament (ACL) tears and patellofemoral joint pain (PFJP). 3 Diminished GM volume has been found in individuals with PFJP compared to control participants. ...
Article
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Context: The hip abductor muscles, mainly the gluteus medius, are responsible for controlling hip adduction in a closed kinetic chain. Frontal plane knee alignment, assessed during functional activities such squatting, jumping and running, may overload joint structures, like the anterior cruciate ligament and patellofemoral joint. The hand-held dynamometer is reliable and effective for testing the muscular strength of the hip abductors. Objectives: 1. To assess the concurrent validity between the gluteus medius clinical test and a maximum isometric force test of the hip abductors using the hand-held dynamometer; (2) to determine the intra and inter-examiner reliability for the application of the gluteus medius clinical test; and (3) to describe reference values of gluteus medius clinical test on a population of youth athletes. Design: Cross-sectional. Methods: Thirty healthy individuals were recruited for validity and reliability testing. On the first day, participants performed the maximal isometric test of the hip abductors, measured via hand-held dynamometry. On the following week, the gluteus medius clinical test was performed. Intraclass correlation coefficients (ICC2,2) were computed for the reliability analysis, with a 95% confidence interval. To generate reference values, the gluteus medius clinical test was performed on 273 athletes. Results: The results of this study indicated a weak positive correlation (r = 0.436, p = 0.001) between tests, which indicates that they examine different domains of gluteus medius muscle function, likely endurance and muscle strength. The magnitude of computed ICCs (>0.95) indicates excellent intra- and inter-examiner reliability. Conclusion: The findings of the current study indicate that the gluteus medius clinical test is reliable and examines a domain of muscular function not fully captured by HHD. The clinical test developed in this study is low-cost and can be included for gluteus medius assessment. Level of evidence: Level 3.
... To date, several studies have shown a link between the occurrence of dynamic valgus in single-leg tasks and weak hip strength, mainly among female participants for abductors [46,[51][52][53][54][55], external rotators [45,46,52,53] and extensors [46,52], but also in males for abductors [51][52][53] external rotators [45,52,53] and extensors [52,53]. However, some studies are of the opposite position, confirming the belief that evidence of the relationship between hip strength and DKV is conflicting [56,57]. The relationship between hip muscle strength and dynamic knee valgus undoubtedly depends on movement tasks that are used to assess valgus, i.e., ballistics, running, walking, cutting, squats, single-leg, double-legged. ...
... The decreased strength of hip abductors, extensors and external rotators was associated with DKV during single-leg drop landings among subgroups of healthy women (p < 0.05). The difference in the results of the kinematic evaluation of the lower limbs between the test tasks of single-leg and double-legs is also due to different demands and muscle recruitments, which, among others, require greater eccentric work to provide control in the frontal plane angles [57]. During single-leg motor tasks, more eccentric work is required of the standing leg hip abductors to resist the contralateral pelvic depression and femoral adduction. ...
Article
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Dynamic knee valgus (DKV) as an incorrect movement pattern is recognized as a risk factor for lower limb injuries. Therefore, it is important to find the reasons behind this movement to select effective preventive procedures. There is a limited number of publications focusing on specific tasks, separating the double-leg from the single-leg tasks. Test patterns commonly used for DKV assessment, such as single-leg squat (SLS) or single leg landings (SLL), may show different results. The current review presents the modifiable factors of knee valgus in squat and landing single-leg tests in healthy people, as well as exercise training options. The authors used the available literature from PubMed, Scopus, PEDro and clinicaltrials.gov databases, and reviewed physiotherapy journals and books. For the purpose of the review, studies were searched for using 2D or 3D motion analysis methods only in the SLL and SLS tasks among healthy active people. Strengthening and activating gluteal muscles, improving trunk lateral flexion strength, increasing ROM dorsiflexion ankle and midfoot mobility should be taken into account when planning training programs aimed at reducing DKV occurring in SLS. In addition, knee valgus during SLL may occur due to decreased hip abductors, extensors, external rotators strength and higher midfoot mobility. Evidence from several studies supports the addition of biofeedback training exercises to reduce the angles of DKV.
... For example, hip external rotators (ER) strength is necessary to control a high hip external moment of internal rotation during dynamics tasks (Powers, 2010). Although conflicting evidence between hip ER strength and lower limb movement during single leg squatting and other dynamic tasks (Dix et al., 2019), hip ER weakness is related to increased hip internal rotation (IR) during SLS and step-down tasks (Araújo et al., 2017;Willy and Davis, 2011). Moreover, excessive hip internal rotation is association with lower limb injuries (Hewett et al., 2005). ...
... Nakagawa et al. found in individuals with PFPS less hip external rotation strength compared to controls without PFPS and only the females with PFPS had more hip internal rotation (Nakagawa et al., 2012). Dix et al. showed association between hip strength and knee valgus during single-leg ballistic tasks, but not in slow tasks like the single-leg squat (Dix et al., 2019). Methodological differences such as the knee flexion range of motion considered for analysis, the type of task performed, even sample profile (presence of pathologies, previous injuries) and possibly differences in the movement analysis techniques (2D or 3D) could be pointed out as reasons for these conflicting results. ...
Article
Introduction Single-leg squat (SLS) is a test commonly used to assess lower limb function in rehabilitation. Increased hip adduction and internal rotation (IR) is associated with dynamic knee valgus, which is related to hip and knee overload. Proximal and distal factors, such as hip passive stiffness, poor hip muscle strength and excessive foot misalignment may influence hip movement. However, previous studies focus on how proximal and distal factors affected knee joint movement and did not reported the influence on hip joint. Objective This study investigated the association of hip external rotators (ER) strength, hip passive stiffness and shank-forefoot alignment (SFA) with hip adduction and IR during SLS. Design Cross-sectional study. Method Forty-six health participants of both sexes (23.47 ± 4.29 years, 60.40 ± 11.28 kilograms, 1.67 ± 8.9 meters) had SFA, hip ER torque, hip passive stiffness and hip kinematics assessed. Multiple linear regressions were performed to identify the factors which associated with mean and peak hip adduction and IR movement during SLS. Results Only hip passive stiffness was associated with mean (R²= 0.164; Confidence Interval (CI) 95%= [-0.250, -0.048]; p= 0.005) and peak (R²= 0.116; CI 95%= [-0.223, -0.210]; p= 0.019) hip IR movement. Conclusion Hip passive stiffness was associated with mean and peak hip IR movement during the SLS. These results suggest that individuals with reduced hip passive stiffness demonstrate increased hip IR movement during SLS.
... In fact, muscles not crossing the knee, such as the gluteal muscles, could also contribute significantly to control dynamic knee valgus by femoral abduction or external rotation (Sritharan et al., 2012). The relationship between muscle strength, mainly hip strength, and dynamic knee valgus has widely been studied (Dix et al., 2018;Malloy et al., 2016;McCurdy et al., 2014;Neamatallah et al., 2020). A meta-analysis from Dix et al. (Dix et al., 2018) showed that hip abduction, extension, and external rotation strength is negatively correlated with dynamic knee valgus during ballistic single-leg tasks in asymptomatic females. ...
... The relationship between muscle strength, mainly hip strength, and dynamic knee valgus has widely been studied (Dix et al., 2018;Malloy et al., 2016;McCurdy et al., 2014;Neamatallah et al., 2020). A meta-analysis from Dix et al. (Dix et al., 2018) showed that hip abduction, extension, and external rotation strength is negatively correlated with dynamic knee valgus during ballistic single-leg tasks in asymptomatic females. This means that the stronger the hip muscles are, the less chances of dynamic knee valgus. ...
Article
Objectives To assess a relationship between lower limb muscle activity and the frontal plane knee kinematics during a single-legged drop jump. Design Correlation study; Setting Functional Anatomy Laboratory. Participants 35 healthy collegiate male athletes. Main outcome measures Muscle activity (%MVIC) of gluteus maximus, gluteus medius, biceps femoris, semitendinosus, vastus medialis quadriceps, vastus lateralis quadriceps, medial gastrocnemius and lateral gastrocnemius; peak knee frontal plane projection angle; and Pearson's correlation coefficients between muscle activity and peak knee frontal plane projection angle. All outcomes were assessed for both dominant and non-dominant limbs. Results Significant correlations (r = 0.46–0.60, P < 0.05) were found between the muscle activities of the gluteus maximus, gluteus medius, biceps femoris, and semitendinosus, when compared to the knee frontal plane projection angle. Conclusion Gluteal muscles and hamstring muscles are associated with the peak knee frontal plane projection angle during a single-legged drop jump test. Thus, gluteal and hamstring muscle activities should be considered when developing rehabilitation or injury prevention programs.
... 19,24,26 Moreover, observed relationships between hip weakness and increased peak knee abduction during athletic activities are inconsistent. [30][31][32][33] Knee abduction angles can be influenced by lower leg or foot posture or biomechanics (i.e. pes planus or cavus, subtalar pronation or supination, and/or tibial rotation), external forces that may contribute to an external knee abduction moment (i.e. ...
... 12,15,34 In fact, criticisms of traditional hip strength assessment measures include the unidirectional, non-weight-bearing positions that may not be reflective of athletic movements. 24,30,35,36 This debate can leave clinicians uncertain of how best to assess hip strength and whether traditional measures even relate to athletic movement. ...
Article
Purpose: Altered hip strength is a risk factor for lower extremity injury but its relationship to biomechanical dysfunction is debated. Hip strength assessment methods are criticized for using unidirectional, non-weight-bearing positions which may not be representative of athletic activity and may affect comparison to biomechanical analysis of athletic tasks. A weight-bearing task may better represent hip muscle function during these movements. The aim of this study was to identify EMG and force differences for a clinical weight-bearing method of hip strength (the squat-hold) to traditional non-weight-bearing maximal voluntary isometric contractions (MVICs) for hip abduction, extension, and external rotation. Methods: Twenty-nine healthy volunteers (23 female, 6 male; 23.3±5.8 years) performed the squat-hold, sidelying abduction, prone extension, and seated hip external rotation MVICs. The squat-hold was performed by exerting a bilateral, maximal force against a rigid strap encircling both knees in a semi-squatted position. Surface electromyography (EMG) recorded peak activation of the gluteus medius (GMed), gluteus maximus (Gmax), and tensor fascia lata (TFL) and a handheld dynamometer simultaneously measured force during all tasks. Peak activation was compared between the squat-hold and each MVIC using paired t-tests. Force was compared across tasks using a one-way ANOVA. Results: Greater force was observed during the squat-hold than the external rotation MVIC, but abduction and extension MVICs yielded greater force than the squat-hold. GMax activation was higher during the squat-hold than the external rotation task. TFL activation was higher during the abduction MVIC than the squat-hold but GMed activation was similar across tasks. Peak GMax activation was similar between the extension MVIC and squat-hold. Conclusions: Squat-hold force may have been reduced due to altered gluteal moment arms, which affected the length-tension relationship. Clinicians should consider the squat-hold as an alternative assessment of external rotation force, but should continue to assess abduction and extension force with MVICs. Researchers should examine positions optimizing length-tension relationships to better relate motor function and movement patterns.
... Most studies have been chosen jump landings and single-leg squats tasks and few have addressed the occurrence of this movement dysfunction during running. Dix et al. [13], in a systematic review, found only two articles that tested the relationship between hip abductors strength and dynamic valgus during running, with contradictory results and low to moderate methodology quality. ...
... Whereas, there are no association to core endurance (ASBT), posterolateral hip strength or hip and ankle ROM. It contradicts previous studies that used different tasks for testing dynamic valgus structural and functional characteristics and corroborates with findings that the relationship between physical variables and movement dysfunctions might be task-dependent [12,13]. Dynamic valgus is considered a medial displacement of the knee during functional tasks and a 3D motion analysis evaluation has shown to be imperative to adequately identify this motion dysfunction, since in the present study was found that each component of dynamic valgus presented different correlations with predictor variables. ...
... Hence, previous studies conducted exercise intervention targeting the kinetic chain of DKV [4]. During closed chain activities, due to the interdependent of joint motions, excessive motions from one joint may overload subsequent tissues in the kinetic chain [5,6]. There are two types of kinetic chains related to DKV, which are top-down (i.e., proximal origins) and bottom-up (i.e., distal origins). ...
... Regarding the topdown kinetic chain, the function of muscles and other soft tissues either at the trunk or hip joint may influence the occurrence of altered kinematic patterns at the subsequent distal joints [7]. It was shown that weakness of hip musculature was associated with greater knee valgus during single leg ballistic and single leg squat tasks [6]. Hip and trunk muscle strengthening are commonly recommended to modify lower limb kinematics such as excessive hip medial rotation and adduction during weightbearing tasks and to treat and prevent injuries at distal joints of lower limbs [8]. ...
Article
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The study investigated the influence of ankle strength and its range of motion (ROM) on knee kinematics during drop landing. Fifteen male and fifteen female university athletes with a normal range of dynamic knee valgus (DKV) (knee frontal plane projection angle: men = 3° to 8°, females = 7° to 13°) were recruited. They performed drop landing at height 30 cm and 45 cm with three-dimensional motion capture and analysis. Knee angles were compared at specific landing phases. Isokinetic ankle strength was tested at 60°/s angular velocity while the weight-bearing lunge test was conducted to evaluate ankle ROM. For males, strength for both plantarflexors and dorsiflexors were associated with knee kinematics at both heights (30 cm: r = −0.50, p = 0.03; 45 cm: r = −0.45, p = 0.05) during maximum vertical ground reaction force (MVGRF) phase. For females, ankle invertor strength and knee kinematics were associated at both 30cm (r = 0.53; p = 0.02,) and 45 cm landing heights (r = 0.49, p = 0.03), while plantarflexor strength and knee kinematics showed a significant association during initial contact (r = 0.70, p < 0.01) and MVGRF (r = 0.55, p = 0.02) phases at height 30 cm only. Male and female athletes with normal range of DKV showed a significant relationship between ankle strength and knee kinematics at specific landing phases. These relationships varied with increased landing height.
... 3---5 The strength of the hip external rotator (HER) and extensor (HEX) muscles has been related to the dynamic control of the lower limb in weight-bearing tasks, 6,7 as well as related to balance in osteopenic older women. 8 Specifically, individuals with greater HER strength present reduced knee dynamic valgus 9 with attenuation of anterior shear forces at the tibiofemoral joint. 10,11 In addition, modifications in landing technique associated with increased HEX strength reduced peak patellar tendon force during the landing task by up to 26%. 12 Therefore, weakness of these hip muscles has been associated with the development of patellofemoral pain, 13,14 patellar tendinopathy, 8 and knee ligamentous injuries. ...
Article
Background: The use of predictive equation of muscular torque can reduce physical effort and time spent during evaluation. Objectives: To establish, validate, and test the accuracy of a prediction equation to estimate the hip external rotators (HER) torque in adults and older adults by means of hip extensors (HEX) torque measurement. Methods: Eighty-three healthy adults (development set) were assessed to test the association of HEX and HER torques and to establish the prediction equation. A separate 36 adults and 15 older adults (validation sets) were assessed to test the ability of the equation to estimate HER torque. Hip isometric strength was assessed by a handheld dynamometer. Results: Simple linear regression analysis revealed that HEX torque was associated with HER torque (r=0.80; p<0.0001), resulting in the following prediction equation: HERtorque=-0.02+(0.58 * HEXtorque). Paired t-test revealed no difference between directly measured and predicted values of HER torque in adults (mean difference=0.02; 95% CI=-0.115, 0.072) and older adults (mean difference=0.05; 95% CI=-0.02, 0.12). Conclusion: The HEX and HER torques were strongly correlated. The prediction equation was valid, accurate, and can be used to estimate HER muscle strength in healthy adults and older adults, requiring only the direct measurement of HEX torque.
... Poor hip control may lead to an adducted and internally rotated femur allowing for abnormal patellar tracking, increased patellofemoral joint stress and subsequent articular cartilage wear [2]. Decreased hip abductor and external rotator muscle strength has been reported to be a risk factor for PFP injury [7]. ...
Article
Purpose The purpose of this study was to examine how attentional focus during training influences the effects of a 6-week hip-knee strength training program on pain, function, strength, and kinematics in males and females with Patellofemoral pain (PFP). Methods Seventy-five males and females with PFP were randomly allocated to a group that trained with an internal focus (n = 25), a group that trained with an external focus (n = 25), or a control group (n = 25). All patients completed testing before (baseline) and after (posttest) the 6-week period. The primary outcome was pain, assessed by Visual Analog Scale (VAS). The secondary outcomes were function, hip muscles strength and lower extremity kinematics, assessed by Kujala Questionnaire, handheld dynamometer and a 2-D motion capture, respectively. All outcomes were measured at the baseline and after the 6-week intervention. Analysis of covariance was used to compare posttest outcomes among the groups while accounting for group differences in baseline performance. Results The hip-knee strengthening exercises resulted in improved knee valgus (ES(95 % CI) = 0.43(0.26 to 0.75), p = 0.03), and external rotator strength (ES(95 % CI) = 0.51(0.12 to 0.78), p = 0.03) for males and females who trained with an external compared to internal focus. Conclusions Our findings indicate that males and females with PFP may benefit from completing a hip-knee strengthening training program with an external focus vs. an internal focus. Physical therapists and clinicians should consider using instructions that promote an external focus when implementing hip-knee strengthening training programs with PFP patients. This result could be strengthened or re-enforced by larger studies with longer follow up.
... Previous meta-analyses observed that reduced hip abduction strength is associated with dynamic knee valgus during single-leg squat tasks. 41 This dynamic knee valgus may be the result of femoral adduction (relative to the pelvis), tibial abduction (relative to the femur), or the combination of both during weight-bearing activities. 42,43 Also, dynamic knee valgus is positively associated with knee pain severity. ...
Article
Objective The objective of this study was to compare proximal, local, and distal muscle morphology in women with and without patellofemoral pain (PFP). Materials and Methods Proximal, local, and distal muscle thicknesses (MTs) were obtained with B-mode sonography in healthy (control group [CG], n = 20) and PFP (PFP group, n = 20) women. In addition, muscle mass was measured by the sum of the synergistic MTs. Data were analyzed by independent t-test, Mann-Whitney U test, and effect size. Results PFP women had smaller gluteus medius ( P = .02, d = 0.7), vastus medialis ( P < .01, d = 1.0), and flexor digitorum brevis ( P < .01, d = 1.0) MT and greater gastrocnemius medialis ( P = .04, d = 0.6) MT than CG. Quadriceps muscle mass ( P = .01, d = 0.8) and foot muscle mass ( P = .008, d = 0.9) were smaller, while plantar flexor muscle mass was greater in the PFP group than in CG ( P = .01, d = 0.8). Conclusion PFP women have proximal, local, and distal MT alterations in comparison with CG, which may explain possible changes in muscle strength and functionality.
... The relationship between posterolateral hip strength and dynamic knee valgus is conflicting and may be conditional to task demand. A systematic review (Dix, Marsh, Dingenen, & Malliaras, 2019) showed no relationship between weaker posterolateral hip strength and greater dynamic knee valgus for single leg squat and double leg landing tasks, but lower dynamic knee valgus was associated with greater posterolateral hip strength. ...
Article
Objective To compare the effectiveness of adding anteromedial versus posterolateral hip musculature strengthening to knee strengthening in women with patellofemoral pain (PFP). Design Randomized controlled trial. Setting University physiotherapy clinic. Participants Fifty-two women with PFP were randomized to receive either anteromedial (AMHG) or posterolateral (PLHG) hip musculature strengthening. Main outcome measures The primary outcomes were pain intensity by the numeric pain rating scale and function by the Anterior Knee Pain Scale in six weeks. Secondary outcomes were pain and function at six months, global perceived effect at six weeks and six months, pain in step down, isometric torque of abductors, adductors and hip rotators measured with hand-held dynamometer, and dynamic knee valgus by step down in six weeks. Results Both groups showed improvement in primary outcomes; however, no differences were found between groups in pain intensity and function in six weeks and the secondary outcomes. Group x time interaction found superior gains in abductor strength in the PLHG and increase in the strength of the adductors and internal rotators in AMHG. Conclusion There was no difference between the addition of anteromedial or posterolateral hip musculature strengthening to knee strengthening in improving pain and function in women with PFP.
... [18][19][20] Moreover, athletes sustaining a noncontact knee injury had increased knee valgus during a single-leg drop vertical jump compared to uninjured athletes. 18 Hip abductor strength controls femoral abduction, a component of knee valgus, 21,22 and hip abductor weakness can predict non-contact anterior cruciate ligament injuries. 23 These studies suggest that knee valgus and hip abductor weakness are risk factors of knee injuries, but they have not been examined for their relationship to upper extremity injuries in baseball. ...
Article
Full-text available
Background: The single-leg step down task (SLSD) is a clinical tool to assess movement and control of the lower extremity and trunk. Hip abduction weakness may impact movement quality during the SLSD, however the relationships between movement and strength are unclear. Purpose: To determine the relationship between hip abduction isometric strength and movement during the SLSD of trunk lean, pelvic drop, knee valgus, and hip flexion. Study design: Cross sectional, cohort study. Methods: One hundred-eighteen Minor League baseball players (age=21.6 ± 2.0 years; n=68 pitchers, n=50 position players) participated. Bilateral hip abduction isometric strength was measured using a handheld dynamometer (HHD), and then multiplied by distance from the greater trochanter to the HHD and expressed as hip abduction torque. Video cameras captured the SLSD, with participants standing on one leg while lowering their contralateral heel to touchdown on the floor from a 0.203m (8in.) step. Trunk lean, trunk flexion, pelvic drop, knee valgus, and hip flexion were measured using Dartfish at heel touchdown. A value of 180° indicated no knee valgus. Pearson correlations examined the relationships between hip abduction torque and SLSD motions. Results: There were no significant correlations for position players. For pitchers, on the lead leg increased hip abduction torque weakly correlated with a decrease in knee valgus (r= 0.24, p=0.049). Also for pitchers on the trail leg, increased hip abduction torque weakly correlated with decreased pelvic drop (r= -0.28, p=0.021). Conclusion: Hip abduction strength contributes to dynamic control of the trunk and legs. Specifically in pitchers, hip abduction weakness was related to increased movement of the lower extremity and lumbopelvic regions during the dynamic SLSD task. These deficits could translate to altered pitching performance and injury. Levels of evidence: 2.
... While there was mixed evidence on the role of peak hip flexion motion on ACL injury risk, weaker hip abduction strength was found to be associated with increased ACL injury risk [17]. This is likely due to the increased hip adduction motion that results in dynamic valgus at the knee which predisposes the ACL to higher levels of shear force [15,18,52]. ...
Article
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Anterior cruciate ligament (ACL) injuries are the most common ligament injury of the knee, accounting for between 100,000 and 200,000 injuries among athletes per year. ACL injuries occur via contact and non-contact mechanisms, with the former being more common in males and the later being more common in females. These injuries typically require surgical repair and have relatively high re-rupture rates, resulting in a significant psychological burden for these individuals and long rehabilitation times. Numerous studies have attempted to determine risk factors for ACL rupture, including hormonal, biomechanical, and sport- and gender-specific factors. However, the incidence of ACL injuries continues to rise. Therefore, we performed a systematic review analyzing both ACL injury video analysis studies and studies on athletes who were pre-screened with eventual ACL injury. We investigated biomechanical mechanisms contributing to ACL injury and considered male and female differences. Factors such as hip angle and strength, knee movement, trunk stability, and ankle motion were considered to give a comprehensive, joint by joint analysis of injury risk and possible roles of prevention. Our review demonstrated that poor core stability, landing with heel strike, weak hip abduction strength, and increased knee valgus may contribute to increased ACL injury risk in young athletes.
... Strong hip and thigh muscles are thought to increase patellar stability by absorbing external hip and knee moments, preventing movement patterns associated with the LPD mechanism of injury (6). In other patient populations, hip muscle weakness has been associated with knee valgus (26), and quadriceps weakness with reduced knee exion on single leg landing (27,28). Higher quadriceps strength is also protects against patellofemoral joint cartilage loss and is associated with less pain and higher physical function, in people with patellofemoral osteoarthritis (29). ...
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Background: lateral patellar dislocations mainly affect active teenagers and young adults. To help people recover, non-surgical exercise-based treatment is often recommended but the optimal exercise-based treatment is unknown. Currently, treatment outcomes after this injury are variable. Common problems include recurrent dislocation, reduced activity levels, and later surgery. A programme of intense leg resistance exercises, and dynamic exercises related to participants’ activity-related goals, has rationale, but has not been previously reported. In line with Medical Research Council guidance, this study aimed to assess the acceptability of a novel evidence-based exercise programme for adults after acute lateral patellar dislocation and the feasibility of future research evaluating this treatment. Methods: a single-group prospective study was conducted at the John Radcliffe Hospital, Oxford, UK. Participants were 16 years or older with an acute first-time or recurrent lateral patellar dislocation. Participants received up to six face-to-face, one-to-one, physiotherapy sessions, over maximum three months, and performed intensive home exercises independently at least three times per week. Strategies to increase exercise adherence were used. Primary objectives were to determine the number of eligible patients, the recruitment rate (proportion of eligible patients that provided written informed consent), participant adherence to scheduled physiotherapy sessions and self-reported adherence to prescribed exercise, and intervention acceptability to participants measured by attrition and a study-specific questionnaire. Data were analysed using descriptive statistics. Results: 15/22 (68%) patients with a lateral patellar dislocation were eligible. All eligible (100%) were recruited. 2/15 (13%) participants provided no outcome data, 2/15 (13%) provided partial outcome data, and 11/15 (73%) provided all outcome data. Questionnaire responses demonstrated high intervention acceptability to participants. Participants attended 56/66 (85%) physiotherapy sessions and 10/11 (91%) participants reported they ‘always’ or ‘often’ completed prescribed exercise. One participant redislocated their patella; another experienced knee pain or swelling lasting more than one week after home exercise on three occasions. Conclusion: the intervention appeared acceptable to adults after acute lateral patellar dislocation and future larger-scale research appears feasible. Future research should estimate feasibility outcomes with increased precision and assess participants’ willingness to be randomised to different treatments across multiple centres. Trial registration: ClinicalTrials.gov NCT03798483, registered January 10, 2019 https://clinicaltrials.gov/ct2/show/NCT03798483?term=INDEX-KD&draw=2&rank=1
... Dynamic knee valgus (DDV) is a biomechanical deviation occurring in 3 movement plans and involving contralateral pelvis fall simultaneously with the internal rotation and adduction of the femur [1]. For activities on one leg, hip abductors prevent pelvic fall and hip adduction [2]. Especially gluteus medius (GMed) muscle strength is found to have a strong relationship with DDV and postural stabilization (PS) [3][4][5]. ...
... The primary rationale for prescribing the side-stepping exercise has been to strengthen hip abductors and lateral hip rotator muscles [4][5][6][7][8][9][10][11][12][13]. The development of control and strength of muscles that contribute to hip abduction and lateral rotation has been regarded as a key component in the prevention and rehabilitation J o u r n a l P r e -p r o o f of lower limb injuries [14][15][16], and in the correction of undesirable movement patterns characterized by excessive femoral medial rotation and adduction [17][18][19] Implicitly and explicitly, the side-stepping exercise with the band around the forefeet has been assumed to produce an external torque of medial rotation of the femur around the pelvis, which in turn would be counteracted by hip lateral rotator muscles [4,5,10,13,20]. ...
Article
Full-text available
Background The way movement-based exercises affect targeted muscles is not always obvious. Side stepping with an elastic band around the forefeet is aimed at strengthening hip abductors and lateral rotator muscles, with the premise that it creates an external torque of adduction and medial rotation of the femur around the pelvis that needs to be counteracted by hip muscles. However, hip torques during this exercise have not been previously quantified. Research question Is the premise that the side-stepping exercise creates an external torque of adduction and medial rotation of the femur around the pelvis correct? Methods Thirty-six adults performed the exercise in an upright and a squat posture while 3D kinetic and kinematic data were collected. Hip muscle torques were calculated using inverse dynamics. The effect of posture and potential interactions with sex, side-stepping phases, and trailing/leading directions were analyzed using Pearson correlation and mixed-model ANOVAs. Result A hip net muscle torque of extension, abduction and medial rotation was required to perform the exercise, regardless of phase and direction. The net muscle torque towards medial rotation required during the exercise was smaller (P<0.001) in the upright (0.05 to 0.12 N.m.kg⁻¹.m⁻¹ across phases) compared to the squat posture (0.10 to 0.24 N.m.kg⁻¹.m⁻¹). In contrast, hip abductor torque was not affected by posture. When averaged across phases and directions, the normalized hip medial rotator muscle torque was highly correlated with knee flexion (r=0.93, P<0.001). Significance The assumption that the side-stepping with the elastic band on the forefeet creates an external hip torque of medial rotation is erroneous. The resistance imposed to the hip during this exercise is consistent with the goal of strengthening the muscles that contribute to hip abduction and hip medial (not lateral) rotation. Changing the knee flexion angle is an effective way to manipulate hip rotator torque when prescribing this exercise in strength training and rehabilitation programs.
... Due to the functional interdependence that exists between the knee and hip, it is no coincidence that both segments complement each other during training or in the rehabilitation of the lower extremity (Babadi et al., 2018;Barton et al., 2014;Beers, Ryan, Kasubuchi, Fraser, & Taunton, 2008;Cheatham, Stull, Fantigrassi, & Montel, 2018;Cichanowski, Schmitt, Johnson, & Niemuth, 2007;Dix, Marsh, Dingenen, & Malliaras, 2018;Fredericson et al., 2000;Ireland, Willson, Ballantyne, & Davis, 2003;Robinson & Nee, 2007;Rowe et al., 2007;Yu, Shao, Baker, & Gu, 2018). The evidence is consistent in demonstrating that both hip strengthening and neuromuscular exercise has a beneficial effect on the painful symptomatology of the knee (Hislop, Collins, Tucker, Deasy, & Semciw, 2019;Thomson, Krouwel, Kuisma, & Hebron, 2016). ...
Article
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The purpose of the present investigation was twofold 1) To compare the hip and thigh muscular activity of professional soccer players when performing the isometric squat with and without controlled hip contraction; 2) To determine the muscular relationships that take place during these methods of execution of the exercise. Methods: 11 healthy male professional soccer players, randomly performed three modalities of isometric squat at a 60° knee flexion: conventional squat (SQ), squat with hip abduction contraction (SQ-ABD) and squat with hip adduction contraction (SQ-ADD), controlled at 70% of 1 maximum repetition. The activity of the gluteus medius (GM), tensor fasciae latae (TFL), vastus medialis (VM), vastus lateralis (VL), semitendinosus (ST) and biceps femoris (BF) was obtained through surface electromyography. Hip (GM/TFL), quadriceps (VM/VL) hamstrings (ST/BF), and hamstrings/quadriceps (H/ Q) ratios were analyzed. Results: GM increases in SQ-ABD and SQ-ADD compared to SQ (p<.01). The TFL, VL, SM and BF muscles have significantly higher activity in SQ-ADD compared to SQ (p<.05). The VL, VM and BF muscles significantly increase their activity in SQ-ADD compared to SQ-ABD (p <0.05). GM/TFL, VM/VL and ST/BF do not show significant differences between the three isometric squat methods. The H/Q ratio was higher in SQ-ABD and SQ-ADD compared to SQ (p<.01). Conclusion: The squat with hip adduction contraction in a controlled manner increases the muscular activity of the hip and thigh. Performing this combined maneuver can have benefits in sports training and rehabilitation because it increases the H/Q ratio of soccer players. © Federación Española de Asociaciones de Docentes de Educación Física (FEADEF).
... 26 This increase in the angle in a landing action has to do with the pronation that occurs in the foot, the weakness of the hip abductor musculature, a greater internal rotation of the leg and furthermore, may be conditional to task demand. 27 Therefore, given the inconsistencies in the literature regarding the effect of core training on vertical jump performance, together with the paucity of scientific studies in the field of team sports such as handball, the purpose of this study was to evaluate the effect of a core training program on bilateral and unilateral vertical drop jump (VDJ) performance in female handball players. We also evaluated the influence of the intervention on frontal knee projection knee angle (FKPA) during unilateral jumps. ...
Article
Objectives: To evaluate changes on bilateral and unilateral jump performance and frontal knee projection angle after an implementation of a core strength program in female handball players. Equipment and methods: This is a randomized controlled trial study. A total of 20 participants [age = 17.2 (1.9) years, height = 1.7 (0.1) m, weight = 62.8 (7) kg ] were recruited and split in: a core training group and a control group. The core training group participated in 8 weeks in-season of a core strength program (2 times/week). Pre- and post-intervention jump height, contact time and reactive strength index were collected during bilateral and unilateral drop vertical jumps. Frontal knee projection angle was measured only at unilateral drop jumps. Results: Core training group increased the bilateral jump height by 18.8% and showed a statistically significant difference in reactive strength index from pre-intervention [0.07 (0.03)] to post-intervention [0.10 (0.04)]. The core training group also improved the unilateral jump height by 20%, but only at the non-dominant leg. This improvement was accompanied by a statistically significant decreased in the frontal knee projection angle from pre-intervention [13.8 (7.38) degrees] to post-intervention [9.3 (6.09) degrees]. Statistical significant difference was set at p ˂0.05. Conclusion: A core strength training increased jump performance and it could play a role in ACL injury prevention programs in female team players.
... Such mechanism could have impacted the thigh muscle strengths (Kulas et al., 2012). The findings indicated that hip-focused exercise could also have an effect on the knee and ankle joint moment, as Ford et al. (2015) and Dix, Marsh, Dingenen, and Malliaras (2019) previously reported on the importance of hip muscle control in DKV. Southgate, Cleather, Weinert-Aplin, and Bull (2012) reported that musculoskeletal models or isolated strength training were more susceptible to internal kinetics changes than kinematics changes during SLS at 45 knee flexion. ...
Article
Objectives There are two types of kinetic chain in dynamic knee valgus (DKV) namely top-down (proximal origins) and bottom-up (distal origins). This study compared the influence of four-week hip- and ankle-focused exercises on lower limb mechanics during single-leg squat (SLS) among physically active females. Methods Thirty-six physically active females with excessive DKV, were divided into either HIP, ANKLE, or control groups. The intervention groups completed exercises that focused either on the hip or ankle musculature for 12 sessions over four weeks. The SLS test protocol was performed with 3D motion capture at pre- and post-intervention. Data were analyzed with two-way ANOVA test. Results HIP group showed increased dominant knee (F (2.66) = 9.437, P = .001) and ankle (F(2.66) = 16.465, P = .001) sagittal moment during 45° SLS at post-intervention compared to ANKLE and Control group. HIP group also showed increased hip flexion angle for dominant (F(2.66) = 12.032, P = .001) and non-dominant leg (F(2.66) = 3.618, P = .032) compared to other groups during 60° SLS. No other significant differences were observed on other variables. Conclusion DKV did not show any significant changes during SLS after a four-week exercise intervention focusing on hip and ankle joints.
... In fact, a protocol for neuromuscular activation of the abductors and external hip rotators during warm-up has recently been shown to reduce the DKV by 53-63% in youth male soccer players 15 . The relation between hip strength and the dynamic knee valgus seems to be clear 16 , but a possible relation between DKV and neuromuscular response (NMR) as contraction time, stiffness, tone or muscular displacement remain unstudied. The NMR is a combination of biomechanical parameters of the muscle tissue that measured by two different methodologies, the MyotonPro device (mytonPro, Myoton Ltds., Estonia) and Tensiomyography (TMG-BMC. ...
Article
Full-text available
The dynamic knee valgus (DKV) during different sport maneuvers has been widely described as risk factor to develop an anterior cruciate ligament injury. Hip and knee muscles seem to have a crucial role to prevent the dynamic knee valgus. This study aimed to give normative and correlational data about DKV and hip and knee neuromuscular response (NMR) among healthy active males. The hypothesis is that DKV could be correlated with hip NMR. A cross-sectional correlational study. Research Anatomy Laboratory. The study was carried out among 50 active, non-injured males. Dynamic Knee-Valgus angle and lower limb posterior chain muscles Neuromuscular Response. DKV was measured using Kinovea software during a Single-Legged Drop Jump test and NMR was measured using tensiomyography and myotonometry for gluteus maximum, biceps femoris, semitendinosus, lateral and medial gastrocnemius. Right and left limbs were both performed and analyzed independently. No significant correlation was observed between DKV and hip and knee muscles NMR. This study shows normative and correlational data about dynamic knee valgus, tensiomyography and myotonometry for healthy and active males. The DKV control seems to be non-correlated with isolated hip and knee muscles NMR so this suggests it is more about Central Nervous System activity than about isolated muscles NMR.
... [6][7][8] In females in particular, the knee abduction moment increases during landing in the drop vertical jump (DVJ) task and results in knee valgus posture and potential injury. 6) Significant risk factors of knee valgus during jump landing include abnormal knee joint proprioception, [9][10][11][12] lower hip external rotation and low abduction strength, 13,14) range of motion abnormalities, 15,16) and poor trunk control. [17][18][19][20] Proprioception -the recognition of the position of one body part relative to another body part without visual information -is crucial for controlling limb Objective: Knee valgus during jump landing is a cause of knee injuries during sports activities. ...
Article
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Objective: Knee valgus during jump landing is a cause of knee injuries during sports activities. Body recognition is important for maintaining the knees and other body parts in their proper positions. The aim of this study was to investigate whether knee valgus during jump landing in healthy young women is related to the inaccuracy of recognition of bilateral knee positions in the squatting position. Methods: In 39 healthy young women, the degree of knee valgus was evaluated during the drop vertical jump test using the ratio of the knee separation distance to the ankle separation distance. The accuracy of recognition of bilateral knee positions in the squatting position was evaluated by having the blindfolded subjects indicate with their index fingers the subjective positions of their bilateral patellae by placing their fingers on a horizontal bar positioned in front of them 3 cm below the navel. The difference ratio of the recognized distance to the actual distance between the bilateral patellae was measured as an inaccuracy index. Results: The degree of knee valgus during the drop vertical jump test was positively correlated with the degree of inaccuracy of the recognized knee position with the knees in the neutral position (r=0.358, P=0.025). Conclusions: In healthy young women, knee valgus during jump landing was significantly correlated with the inaccuracy in knee position recognition in the squatting posture. This finding suggests that the assessment of knee position recognition in the squatting position could be useful as a screening tool for preventing knee injuries on jump landing during sports activities.
... Strong hip and thigh muscles are thought to increase patellar stability by absorbing external hip and knee moments, preventing movement patterns associated with the LPD mechanism of injury [6]. In other patient populations, hip muscle weakness has been associated with knee valgus [26], and quadriceps weakness with reduced knee flexion on single leg landing [27,28]. Higher quadriceps strength also protects against patellofemoral joint cartilage loss and is associated with less pain and higher physical function, in people with patellofemoral osteoarthritis [30]. ...
Article
Full-text available
Background Lateral patellar dislocations mainly affect active teenagers and young adults. To help people recover, non-surgical exercise-based treatment is often recommended but the optimal exercise-based treatment is unknown. Currently, treatment outcomes after this injury are variable. Common problems include recurrent dislocation, reduced activity levels, and later surgery. A programme of intense leg resistance exercises, and dynamic exercises related to participants’ activity-related goals, has rationale, but has not been previously reported. In line with the Medical Research Council guidance, this study aimed to assess the acceptability of a novel evidence-based exercise programme for adults after acute lateral patellar dislocation and the feasibility of future research evaluating this treatment. Methods A single-group prospective study was conducted at the John Radcliffe Hospital, Oxford, UK. Participants were 16 years or older with an acute first-time or recurrent lateral patellar dislocation. Participants received up to six face-to-face, one-to-one, physiotherapy sessions, over a maximum of 3 months, and performed intensive home exercises independently at least three times per week. Strategies to increase exercise adherence were used. Primary objectives were to determine the number of eligible patients, the recruitment rate (proportion of eligible patients that provided written informed consent), participant adherence to scheduled physiotherapy sessions and self-reported adherence to prescribed exercise, and intervention acceptability to participants measured by attrition and a study-specific questionnaire. Data were analysed using descriptive statistics. Results Fifteen of 22 (68%) patients with a lateral patellar dislocation were eligible. All eligible (100%) were recruited. Two of 15 (13%) participants provided no outcome data, 2/15 (13%) provided partial outcome data, and 11/15 (73%) provided all outcome data. Questionnaire responses demonstrated high intervention acceptability to participants. Participants attended 56/66 (85%) physiotherapy sessions and 10/11 (91%) participants reported they ‘always’ or ‘often’ completed the prescribed exercise. One participant redislocated their patella; another experienced knee pain or swelling lasting more than one week after home exercise on three occasions. Conclusion The intervention appeared acceptable to adults after acute lateral patellar dislocation, and a future randomised pilot trial is feasible. This future pilot trial should estimate attrition with increased precision over a longer duration and assess participants’ willingness to be randomised to different treatments across multiple centres. Trial registration ClinicalTrials.gov NCT03798483 , registered on January 10, 2019
... The video cameras were placed on tripods perpendicular to the frontal and sagittal planes, at a height of 60 cm and a distance of 3.5 m from the landing area. Furthermore, retroreflective markers were placed on specific anatomical landmarks [manubrium sterni, bilateral acromioclavicular joint, Anterior Superior Iliac Spine (ASIS), greater trochanter, lateral and medial femoral epicondyles, and lateral and medial malleolus] [18,19]. ...
Article
Introduction: The present study aimed to compare hip muscle resistance training with and without feedback on trunk, pelvis, and lower extremity motions in frontal and sagittal planes among active females with dynamic valgus. Materials and Methods: Twenty-Nine active females (Mean±SD age: 22.8±2.4 years, height: 1.70±0.6 m, weight: 69±7.1 kg) were randomly assigned to a hip muscle resistance training with feedback group (n=15) or a hip muscle resistance training without feedback group (n=14). Both training programs lasted 6 weeks (3 sessions/week). The peak angles of lateral trunk flexion, contralateral pelvic drop, hip flexion, knee flexion, and valgus during single-leg drop landing and single-leg vertical drop jump were assessed in the research participants at baseline and 6 weeks post-training. Unipodal functional screening tests were captured with two standard digital video cameras. Results: After 6 weeks, significant differences were observed in knee valgus and lateral trunk flexion, contralateral pelvic drop, and knee flexion angles, i.e., compared between hip muscle resistance training with feedback and hip muscle resistance training without feedback (P<0.05), except for non-dominant leg hip flexion in single-leg vertical drop jump (P>0.05). Conclusion: In the explored active females with dynamic valgus, hip muscle resistance training with feedback seems to be better at improving trunk, pelvis, and lower extremity motions in frontal and sagittal planes, compared to hip muscle resistance training without feedback; however, no significant difference was observed concerning hip flexion during single-leg vertical drop jump between the study groups.
... In relation to subjects with GVD, several studies have recommended the improvement of impaired movement patterns and the strengthening of the gluteus medius (Gmed) muscle as a controls hip adduction and internal rotation functionally [7][8][9], it is a major mechanism in preventing knee valgus. For example, it is shown that impairment in the production of hip abductors strength can increase the range of motion of hip adduction and internal rotation during weightbearing activities, this potentially affects the kinematics of the lower extremities and cause knee valgus [10]. ...
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Background: Gluteus medius muscle (Gmed) dysfunction has been confirmed as a functional defect in subjects with Genu Valgum Deformity (GVD). In relation to these subjects, increase Gmed activity without synergist muscles dominance is considered as part of a specialized exercise program. Methods: A total of thirty female recreational athletes with (n=15) and without (n=15) GVD participated in this study. Surface electromyography measured Gmed, tensor fascia latae (TFL), and quadratus lumborum (QL) muscles activity when subjects performed pelvic drop (PD) in three different positions of hip rotations with and without applied isometric hip external rotation force. Results: There were differences in muscle activity between GVD and healthy subjects. The Gmed/TFL and Gmed/QL muscles activity ratio altered when placing the hip in different rotation positions and applying isometric load. Conclusions: The lower extremity muscles activity is affected by GVD, and changing the positions of the hip rotation in the PD task can be associated with altered muscle activity in both GVD and healthy Groups. However, applying isometric hip external rotation during PD can be suggested as an effective intervention to increase Gmed activity.
... A recent review by Dix and colleagues (9) found that the movement patterns of the human body can have different factors and there is still no causal relationship between hip muscle strength and DKV, despite being a potential factor for this pattern. In that same study, it was demonstrated that the weaker hip muscle strength seems to be more likely to be correlated with the DKV, especially in single-leg tasks, which may mean that the DKV is more associated with the type of task performed and its degree of complexity. ...
Article
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Lagares L, Silva M, Macedo R, Lino R, Santos F, Ide B, Almeida L, Bomfim E, Santos C. Dynamic Knee Valgus and its Relationship with Performance in the Countermovement Jump and the Squat Jump. JEPonline 2018;24(6):1-10. The purpose of this study was to test the hypothesis that Dynamic Knee Valgus (DKV) decreased performance in the Countermovement Jump (CMJ) and the Squat Jump (SJ) in judo athletes. Anthropometric measurements of body mass and height were collected, the DKV was analyzed during the Step-Down Test, and the power of the lower limbs was assessed using a contact platform during the CMJ and the SJ. The sample consisted of 39 male judo athletes of which 61.5% had DKV. In the analysis of the maximum height reached between the CMJ and the SJ in the group without DKV, significant differences (P<0.05) and a large effect size (Cohen's d = 1.55) were observed. In the group with DKV, no significant differences were found (P>0.05), in addition to a small effect size (Cohen's d = 0.47). In muscle power, significant differences were observed in the intergroup CMJ (P<0.05) and between the CMJ and the SJ in the group without DKV (P<0.05). Hence, it appears that DKV does not reduce performance in the countermovement jump and the squat jump.
... The video cameras were placed on tripods perpendicular to the frontal and sagittal planes, at a height of 60 cm and a distance of 3.5 m from the landing area. Furthermore, retroreflective markers were placed on specific anatomical landmarks [manubrium sterni, bilateral acromioclavicular joint, Anterior Superior Iliac Spine (ASIS), greater trochanter, lateral and medial femoral epicondyles, and lateral and medial malleolus] [18,19]. ...
Chapter
Basketball is a multi-directional sport that has high lateral and vertical demands. Understanding the biomechanics of jumping, landing, and cutting can help coaches and clinicians better reduce the risk of injury in basketball athletes since abnormal movement strategies can lead to various lower extremity injuries especially to the foot, ankle, and knee. If injured, a rehabilitation and return-to-play plan should incorporate regional (hip-focused) and global (lateral and single-leg focused) interventions to elicit the athlete’s optimal performance and safety. This chapter will focus on the lower extremity movement demands characteristic to the sport of basketball as well as lower extremity joint biomechanics during basketball-specific movements, and biomechanical considerations of basketball-related lower extremity injuries.
Article
Knee injuries such as ACL tears commonly occur and there is a high re-injury rate after primary ACL reconstruction with figures estimated at 25%-33%. Clinicians often use hip strengthening as a key component of knee rehabilitation. Evidence suggests that adopting a "regional" or "proximal" approach to rehabilitation can increase hip strength, but motor control often remains unchanged, particularly during more complex tasks such as running and jumping. It has been previously suggested that the current approach to "regional/proximal" rehabilitation is too basic and is constrained by a reductionist philosophy. This clinical commentary provides the clinician a framework for optimizing knee rehabilitation, underpinned by a more global approach. Although this approach remains hip-focused, it can be easily adapted to modify exercise complexity and key loading variables (speed, direction, flight), which will help the clinician to better replicate the sport specific demands on the knee. Level of evidence: 5.
Article
Objective: to investigate alterations in motor behavior related to pain-related beliefs in persons with peripheral joint conditions. Design: Systematic Review RESULTS: Our database search (Pubmed, Web of Science, Embase, PsycINFO) identified 7390 articles (until September 2019) and nine papers (344 participants) were selected based on the eligibility criteria for selecting studies, i.e. studies in adults with primary peripheral joint conditions, assessing the influence of fear of movement, catastrophizing or anxiety on motor behavior in terms of kinematics, kinetics and muscle activity during active movements.In the acute stage after knee or radius surgery, more catastrophizing and fear were associated with less active joint motion in the operated and adjacent joints. In knee patients in the chronic stage after surgery, increased hip adduction and knee valgus were linked to increased fear of movement during the performance of challenging tasks. Similar results were found in persons with non-surgical chronic knee pain. During gait, no relation between lower limb kinematics and fear of movement was observed. Conclusion: Kinematic alterations appear in tandem with pain-related perceptions in acute stages after surgery. Altered kinematics influenced by pain-related beliefs are also seen in persons with chronic non-surgical and surgical knee pain, when challenging tasks are performed.
Background: Urgency and frequency are common lower urinary tract symptoms (UF-LUTS) in women. There is limited evidence to guide physical therapist-led treatment. Objectives: To compare hip and pelvic floor muscle strength between women with and without UF-LUTS. We hypothesized women with UF-LUTS would demonstrate 1) diminished hip external rotator and abductor strength and 2) equivalent pelvic floor strength and diminished endurance compared to controls. Study design: A matched case-control study. Methods: Women with UF-LUTS (cases) and controls were matched on age, body mass index (BMI), vaginal parity. Examiner measured participants' 1) hip external rotator and abductor strength via dynamometry (maximum voluntary effort against fixed resistance) and 2) pelvic floor muscle strength (peak squeeze pressure) and endurance (squeeze pressure over a 10 second hold) via vaginal manometry. Values compared between cases and controls with paired-sample t-tests (hip) or Wilcoxon signed rank tests (pelvic floor). Results: 21 pairs (42 women): Hip external rotation (67.0 ± 19.0 N vs 83.6 ± 21.5 N; P=0.005) and hip abduction strength (163.1 ± 48.1 N vs 190.1 ± 53.1 N; P=0.04) were significantly lower in cases than controls. There was no significant difference in pelvic floor strength (36.8 ± 19.9 cmH20 vs 41.8 ± 21.0 cmH20; P=0.40) or endurance (234.0 ± 149.6 cmH20*seconds vs 273.4 ± 149.1 cmH20*seconds; P=0.24). Conclusion: Women with UF-LUTS had weaker hip external rotator and abductor muscles, but similar pelvic floor strength and endurance compared to controls. Hip strength may be important to assess in patients with UF-LUTS, further research is needed.
Article
Introduction It is possible to quantify changes in movement patterns through kinematic analysis of landing, especially to quantify changes in pre and post exhaustion situations, however the reliability of this post exhaustion analysis is not known. Objective To verify the inter and intra-examiner reliability of two-dimensional kinematic analysis during the landing of a vertical jump of volleyball athletes, pre and post exhaustion protocol. Experimental Thirty volleyball athletes were recruited, and kinematic analysis was performed during landing, pre and post exhaustion protocol. The angular measurements analyzed were: 1) frontal plane: knee valgus and 2) sagittal plane: anterior trunk inclination, knee flexion and tibiotarsal angle, performed by two examiners. The reliability calculation used the intraclass correlation coefficient (ICC), in addition to the error of measurement (SEM), the coefficient of variation (CV) and the minimum detectable difference (MDD). Results Regarding reliability: ICC=0.95-0.98 (pre) and ICC= 0.83-0.98 (post exhaustion). The CV presented heterogeneous values for the knee valgus and the inclination of the trunk, both pre and post protocol. The SEM from all angles presented values that varied from 0.74º-2.33º and the MDD ranged from 2.55º-5.54º pre protocol and 2.05º-6.45º post protocol. Conclusion 2D kinematic evaluation can be used during landing, before and after the application of an exhaustion protocol, but professionals should pay attention to the angles of the knee valgus and the inclination of the trunk, as they have a large CV.
Article
Background and Aims: Genu valgum is among the most common lower limb malalignments impacting people’s performance. The present study’s objective was to investigate the effects of a corrective exercise protocol utilizing TheraBand on muscle activity during running in individuals with genu valgum. Methods: The present study was a semi-experimental and laboratory study, in which 24 male students (20-30 years old) were randomly divided into the control and experimental groups. Corrective exercises were performed on the experimental group for eight weeks using a thera-band. The electrical activity of selected muscles was recorded via the electromyography system. Statistical analysis was conducted utilizing measures, such as repeated measures Analysis of Variance (ANOVA) (significance level: 0.05). Results: The findings revealed a significant decrease (69.98%) in bicep femoris muscular activity during the stance phase of running posttest compared to pretest (d=1.88, P=0.002). Moreover, a significant decrease (33.77%) in the electrical activity of the semitendinosus muscle was detected in the posttest compared to the pretest (d=0.86, P=0.024). The electrical activity of other muscles did not indicate any significant differences in the posttest compared to the pretest (P>0.05). Conclusion: Decline in bicep femoris muscle activity in individuals with genu valgus indicates the positive impact of rehabilitation via TheraBand as well as enhanced performance in their daily activities.
Article
Objective Synthesize evidence on objectively quantified lower limb strength recovery in people treated surgically or non-surgically after patellar dislocation. Methods MEDLINE, EMBASE, Cochrane Library, SPORTDiscus, PEDro, AMED and CINAHL databases were last searched on July 30th, 2020 for randomized controlled trials and observational studies that objectively quantified lower limb strength in people (any age or sex) treated surgically or non-surgically after patellar dislocation. Results 24 studies were included (877 participants, median age 20.7). All assessed knee extension strength, 11 knee flexion strength, three hip abduction strength, two hip external rotation strength, and one hip flexion, extension, adduction, and internal rotation strength. One randomized controlled trial judged at high risk of bias and two cohort studies with methodological limitations compared lower limb strength recovery between surgically and non-surgically treated people, with conflicting findings. After surgery, median long-term (>8 months) knee extension strength was 82.5% (IQR 78.5–88.2; 13 studies) of the unaffected leg and knee flexion strength was 91.5% (IQR 90.7–96.9; five studies). After non-surgical treatment, median long-term knee extensor strength was 86% (IQR 79.3–87.4; four studies) and mean flexion strength ranged from 95.2 to 96.7% (two studies). Hip strength was always >90% (two studies). Two redislocations during eccentric isokinetic knee testing and knee pain during isokinetic knee extension testing were reported as adverse events. Conclusions Available evidence indicates that after patellar dislocation, knee extension strength deficits in the affected limb are frequently observed and can persist long term, but this remains uncertain due to the limitations of relevant included studies. Whether lower limb strength recovery differs between people treated surgically and those treated non-surgically after patellar dislocation also remains uncertain. Trial registration (PROSPERO CRDX)
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Background A range of non-contact injuries such as anterior cruciate ligament tear, and patellofemoral pain syndrome are caused by disordered knee joint loading from excessive dynamic knee valgus (DKV). Previous systematic reviews showed that DKV could be modified through the influence of hip strength and ankle range of motion. Therefore, the purpose of this systematic review was to examine the effects of exercise intervention which involved either top-down or bottom-up kinetic chains on minimizing DKV in male and female adults and adolescents, with and without existing knee pain. Methodology Electronic searches were conducted in SAGE, Science Direct, SCOPUS, and Pubmed. The search strategy consisted of medical subject headings and free-text search keywords, synonyms and variations of ‘exercise intervention,’ ‘knee alignment,’ ‘dynamic knee valgus’, ‘knee abduction’ that were merged via the Boolean operator ‘AND’ and ‘OR’. The search was conducted on full-text journals that documented the impact of the exercise intervention program involving either the bottom-up or top-down DKV mechanism on the knee kinematics. Furthermore, exercise intervention in this review should last at least one week which included two or three sessions per week. This review also considered both men and women of all ages with a healthy or symptomatic knee problem. The risk of bias of the included studies was assessed by Cochrane risk assessment tool. The protocol of this review was registered at PROSPERO (registration number: CRD42021219121). Results Ten studies with a total of 423 participants (male = 22.7%, female = 77.3%; adults = 249, adolescents = 123; pre-adolescent = 51) met the inclusion criteria of this review. Seven studies showed the significant effects of the exercise intervention program (range from two weeks to ten weeks) on reducing DKV. The exercise training in these seven studies focused on muscle groups directly attached to the knee joint such as hamstrings and gastrocnemius. The remaining three studies did not show significant improvement in DKV after the exercise intervention (range between eight weeks to twelve weeks) probably because they focused on trunk and back muscles instead of muscles crossing the knee joint. Conclusion Exercises targeting specific knee-joint muscles, either from top-down or bottom-up kinetic chain, are likely to reduce DKV formation. These results may assist athletes and coaches to develop effective exercise program that could minimize DKV and ultimately prevent lower limb injuries.
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Jam Sports Conference Proceedings 2021
Article
Purpose: To determine if a pre-season field-based test battery was prospectively associated with non-contact ACL injury in elite female footballers. Methods: In total, 322 elite senior and junior female Australian Rules Football and soccer players had their isometric hip adductor and abductor strength, eccentric knee flexor strength, countermovement jump (CMJ) kinetics, and single-leg hop kinematics assessed during the 2019 pre-season. Demographic and injury history details were also collected. Footballers were subsequently followed for 18 months for ACL injury. Results: 15 non-contact ACL injuries occurred during the follow-up period. Prior ACL injury (odds ratio [OR] = 9.68, 95% confidence interval [95%CI] = 2.67-31.46), a lower isometric hip adductor to abductor strength ratio (OR = 1.98, 95%CI = 1.09-3.61), greater CMJ peak take-off force (OR = 1.74, 95%CI = 1.09-3.61), and greater single-leg triple vertical hop average dynamic knee valgus (OR = 1.97, 95%CI = 1.06-3.63) and ipsilateral trunk flexion (OR = 1.60, 95%CI = 1.01-2.55) were independently associated with increased risk for subsequent ACL injury. A multivariable prediction model consisting of CMJ peak take-off force, dynamic knee valgus, and ACL injury history that was internally validated classified ACL injured from uninjured footballers with 78% total accuracy. Between-leg asymmetry in lower limb strength and CMJ kinetics were not associated with subsequent ACL injury risk. Conclusions: Pre-season field-based measures of lower limb muscle strength and biomechanics were associated with future non-contact ACL injury in elite female footballers. These risk factors can be used to guide ACL injury screening practices and inform the design of targeted injury prevention training in elite female footballers.
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Objective: This research aims to study the connection betweenthe use of cell phones and sex, body mass index and level of PApractice in adolescent schoolchildren.Method: This is a cross-sectional descriptive study conductedwith a total sample of 103 students in compulsory secondaryeducation (ESO), aged between 14 and 17 years. TheQuestionnaire on the Usability of ICT with Internet Connection(CUTIC) was used, specifically the questions related to the use ofcell phones (Jiménez, Alvarado, & Llopis, 2017). BMI was obtainedself-reported and applying the kg/m2 formula (Baile & González-Calderón, 2014), classifying the schoolchildren with the Orbegozofoundation tables (Sobradillo et al., 2004). The level of PhysicalActivity of the sample was assessed with the WHO Global PhysicalActivity Questionnaire (GPAQ) (2014). Informed consent of theparents or legal guardians was provided throughout the procedureand adjusted everything to the Helsinki Declaration of 2013.Descriptive and ANOVA analyses were performed with SPSSStatistics software version 27.0.Results: For the schoolchildren in this study, cell phones are themost commonly used screen devices, with boys being the oneswho use them the most. There seems to be more consensus on thefact that the main reason for the use of these screen devices isrelated to the consultation of social networks. In relation to BMI,the group of schoolchildren with obesity spends too much time onsocial networks, compared to those with normal weight andoverweight.Conclusions: The main conclusion is that cell phones are widelyused by the adolescents studied, especially to consult socialnetworks. Excess weight is related to prolonged periods of use ofthese devices. Boys report a greater use of these mobile devicesfor educational purposes.
Article
Background Dynamic knee valgus, visually represented as medial knee displacement, is associated with anterior cruciate ligament injury. Recently, restrictions in ankle dorsiflexion range of motion have been associated with medial knee displacement. Therefore, interventions potentially increasing ankle dorsiflexion range of motion could alleviate medial knee displacement. The purpose of this pilot study was to explore the acute effects of an intervention to increase ankle dorsiflexion range of motion and reduce medial knee displacement in individuals who display medical knee displacement that is corrected with a heel lift. Methods Eight young participants who displayed medial knee displacement corrected with a heel lift completed a single-session intervention aimed at increasing dorsiflexion range of motion. Immediately before and after the intervention session, dorsiflexion range of motion in three static conditions (passive straight-knee, passive bent-knee, and weight-bearing lunge) and medial knee displacement during an overhead squat were assessed. Findings The single-session training program increased participants' dorsiflexion range of motion in all three static conditions (p = 0.0005 for straight-knee, 0.02 for bent-knee, and 0.01 for lunge) with moderate to large effect sizes (0.55–1.18). Additionally, the training resulted in a significant reduction in medial knee displacement during the overhead squat (p = 0.02). Interpretation The finding indicated that our interventional protocol appears beneficial in increasing dorsiflexion range of motion among individuals with medial knee displacement. Additionally, improving dorsiflexion range of motion may be a promising direction for reducing medial knee displacement, which is a risk factor of anterior cruciate ligament injury.
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Background and purpose: Anterior cruciate ligament injuries are prevalent among the athletic population, imposing a heavy economic burden, and the risk of re-injury. Most current biomechanical screening tasks are performed in the sagittal plane, and there is a need for more screening tools that assess sports specific movements in the frontal plane. The purpose of this study was to determine the reliability of and examine differences between sexes in the performance of the Lateral Bound Test (LBT). Materials/methods: Each subject performed three trials of a LBT which included jumping laterally from one leg over a hurdle and landing on the opposite leg. Two cameras were placed six feet from the landing marker. Maximum dynamic knee valgus using the frontal plane projection angle and knee flexion angle at initial contact and maximal knee flexion were measured upon landing leg using 2D video analysis software. Additionally, video of 10 individuals' trials were analyzed twice with one week between the analyses to obtain intra-rater reliability while 12 participants were retested one week later to determine test-retest reliability. Results: Thirty healthy subjects, 16 males, 14 females participated. Intra-rater reliability was determined to be excellent for all variables (ICC>0.96). In contrast, the test-retest reliability had greater disparity. Test-retest reliability ranged from poor (ICC = 0.47) to excellent (ICC > 0.90). Significant differences existed between the sexes, including males being significantly taller, weighing more, and demonstrating greater bilateral dynamic knee valgus (p < 0.05). No significant differences existed between sexes for knee flexion angles. Conclusion: The new LBT had excellent intra-rater reliability for assessing dynamic knee valgus and initial and maximum knee flexion angle when performing a functional movement in the frontal plane. Furthermore, males landed with more dynamic knee valgus than females which is contradictory to what has been observed with functional screening tools performed in the sagittal plane. Level of evidence: 3b (reliability study).
Chapter
Return to running after an injury is a milestone in the rehabilitation process of an athlete. To guide the patient in the return to running process, a comprehensive understanding of the running demands and the patient’s injury and current condition is paramount. A correct and thorough running implementation can represent a useful training stimulus for the athlete but on the other hand, if introduced too early or with the wrong progression, it can pose a threat for the athlete’s recovery process. For this reason, it is necessary that the patient is properly prepared before return to running and adequately monitored during this process. In this chapter, the authors discuss the return to running process after anterior cruciate ligament reconstruction (ACLR) stating the running demands and the physical criteria to be achieved after this surgery before allowing an athlete to return to run. The same clinical reasoning process can be applied to any other injury considering the running biomechanical demands of that specific area and the relative injury features. Finally, the authors present a return to running progression after ACLR with detailed information about the suggested rehabilitation strategies and their implementation.
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Introduction: Patellofemoral pain syndrome (PFPS) is one of the most common musculoskeletal disorders, and is related to biomechanical factors of the lower extremities. Hip and knee muscle strengthening is a well-known method for the treatment of PFPS, but there is insufficient evidence for its effectiveness in combination with other effective interventions. The purpose of this study was to compare the effect of hip and knee strengthening with internal instruction exercises on pain and dynamic knee valgus in patients with PFPS. Materials and Methods: The present study was a quasi-experimental intervention. 50 men and women with PFPS (18 to 45 years) participated in this study. Subjects were assigned to experimental (n = 25) and control (n = 25) groups. Evaluation of pain was conducted using visual analog scale (VAS) questionnaire, and dynamic knee valgus by two-dimensional video camera. Subjects in the control group received hip and knee strengthening exercises, and in the experimental group performed hip and knee strengthening with internal instruction exercise for six weeks, three sessions per week and each session for 45 minutes. Independent and dependent t tests were used for statistical analysis. Results: Adding internal focus instruction on hip and knee strengthening exercises affected the dynamic knee valgus angle of the patients with PFPS, and significantly reduced the dynamic knee valgus angle (P < 0.001). Moreover, there was no significant statistical effect on pain with the addition of internal focus on hip and knee strengthening exercises. Conclusion: Hip and knee strengthening with internal instructions exercises seem to be more effective in improving dynamic knee valgus than exercises that focus solely on strengthening the hip and knee muscles.
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Injury prediction is one of the most challenging issues in sports and a key component for injury prevention. Sports injuries aetiology investigations have assumed a reductionist view in which a phenomenon has been simplified into units and analysed as the sum of its basic parts and causality has been seen in a linear and unidirectional way. This reductionist approach relies on correlation and regression analyses and, despite the vast effort to predict sports injuries, it has been limited in its ability to successfully identify predictive factors. The majority of human health conditions are complex. In this sense, the multifactorial complex nature of sports injuries arises not from the linear interaction between isolated and predictive factors, but from the complex interaction among a web of determinants. Thus, the aim of this conceptual paper was to propose a complex system model for sports injuries and to demonstrate how the implementation of complex system thinking may allow us to better address the complex nature of the sports injuries aetiology. According to this model, we should identify features that are hallmarks of complex systems, such as the pattern of relationships (interactions) among determinants, the regularities (profiles) that simultaneously characterise and constrain the phenomenon and the emerging pattern that arises from the complex web of determinants. In sports practice, this emerging pattern may be related to injury occurrence or adaptation. This novel view of preventive intervention relies on the identification of regularities or risk profile, moving from risk factors to risk pattern recognition.
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Background: Double-leg forward or drop-jump landing activities are typically used to screen for high-risk movement strategies and to determine the success of neuromuscular injury prevention programs. However, research suggests that these tasks that occur primarily in the sagittal plane may not adequately represent the lower extremity biomechanics that occur during unilateral foot contact or non-sagittal plane movements that are characteristic of many multidirectional sports. Purpose: To examine the extent to which lower extremity biomechanics measured during a jump landing on a double leg (DL) after a sagittal plane (SAG) movement is representative of biomechanics measured during single-leg (SL) or frontal plane (FRONT) jump landing tasks. Study design: Controlled laboratory study. Methods: Lower extremity biomechanics were measured in 15 recreationally active females (mean age [±SD], 19.4 ± 2.1 years; mean height, 163.3 ± 5.9 cm; mean weight, 61.1 ± 7.1 kg) while performing SAGDL, SAGSL, FRONTDL, and FRONTSL jump landing tasks. Repeated-measures analyses of variance examined differences in lower extremity biomechanics between the 4 tasks, and linear regressions examined the extent to which an individual's biomechanics during SAGDL were representative of their biomechanics during SAGSL, FRONTDL, and FRONTSL. Results: Lower extremity kinematics and kinetics differed by condition, with the SAGDL task generally eliciting greater hip and knee flexion angles and lower hip and knee forces than the other tasks (P < .05). Although biomechanics during the SAGDL task were strongly associated with those during the FRONTDL task (R (2), 0.41-0.82), weaker associations were observed between SAGDL and single-leg tasks for hip kinematics (R (2), 0.03-0.25) and kinetics (R (2), 0.05-0.20) and knee abduction moments (R (2), 0.06-0.18) (P < .05). Conclusion: Standard double-leg sagittal plane jump landing tasks used to screen for ACL injury risk and the effectiveness of ACL injury prevention programs may not adequately represent the lower extremity biomechanics that occur during single-leg activities. Clinical relevance: These results support further investigation of single-leg multidirectional landings to identify high-risk movement strategies in female athletes playing multidirectional sports.
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Background: The relationships between hip abductor and extensor strength and frontal plane hip and knee motions that are associated with anterior cruciate ligament injury risk are equivocal. However, previous research on these relationships has evaluated relatively low-level movement tasks and peak torque rather than a time-critical strength measure such as the rate of torque development (RTD). Hypothesis: Females with greater hip abduction and extension RTD would exhibit lesser frontal plane hip and knee motion during a single-leg jump-cutting task. Study design: Descriptive laboratory study. Methods: Forty recreationally active females performed maximal isometric contractions and single-leg jump-cuts. From recorded torque data, hip extension and abduction RTD was calculated from torque onset to 200 ms after onset. Three-dimensional motion analysis was used to quantify frontal plane hip and knee kinematics during the movement task. For each RTD measure, jump-cut biomechanics were compared between participants in the highest (high) and lowest (low) RTD tertiles. Results: No differences in frontal plane hip and knee kinematics were identified between high and low hip abduction RTD groups. However, those in the high hip extension RTD group exhibited lower hip adduction (high, 3.8° ± 3.0°; low, 6.5° ± 3.0°; P = .019) and knee valgus (high, -2.5° ± 2.3°; low, -4.4° ± 3.2°; P = .046) displacements during the jump-cut. Conclusion: In movements such as cutting that are performed with the hip in a relatively abducted and flexed position, the ability of the gluteus medius to control hip adduction may be compromised. However, the gluteus maximus, functioning as a hip abductor, may take on a pivotal role in controlling hip adduction and knee valgus motion during these types of tasks. Clinical relevance: Training with a specific emphasis on increasing explosive strength of the hip extensors may be a means through which to improve frontal plane hip and knee control during high-risk maneuvers such as cutting.
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The concentric and eccentric strength profile and muscular balance of the hip joint are important parameters for success in soccer. This study evaluated the reliability for the assessment of hip abduction and adduction isokinetic strength over a range of angular velocities (30 and 90 degrees/s) and types of muscular actions (concentric and eccentric) in young soccer players. The reliability for the assessment of reciprocal (conventional and functional) and bilateral torque ratios was also examined. Fifteen male soccer players (15 +/- 1 years) performed two sessions, separated by three days. The testing protocol consisted of five maximal concentric and eccentric hip abductions and adductions of both legs at angular velocities of 30 degrees/s and 90 degrees/s. The peak torque was evaluated in young soccer players using an isokinetic dynamometer (Cybex Norm), and the reciprocal strength ratios (conventional and functional) and bilateral ratios (non-preferred to preferred leg ratios) were calculated. The test-retest reliability for the assessment of peak torque (ICC= 0.71-0.92) and of reciprocal muscle group ratios (ICC= 0.44-0.87) was found to be moderate to high. Bilateral torque ratios exhibited low to moderate reliability (ICC= 0.11-0.64). In conclusion, isokinetic strength of hip abductor and adductor muscles and the conventional and functional strength ratios can be reliably assessed in young soccer players, especially at low angular velocities. The assessment, however, of bilateral strength ratios for hip abductor/adductor muscles should be interpreted with more caution.
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BACKGROUND: Prospective studies have reported that abnormal movement patterns at the trunk, hip, and knee are associated with noncontact anterior cruciate ligament (ACL) injuries. Impaired hip strength may underlie these abnormal movement patterns, suggesting that diminished hip strength may increase the risk of noncontact ACL injury. PURPOSE: To determine whether baseline hip strength predicts future noncontact ACL injury in athletes. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Before the start of the competitive season, isometric hip strength (external rotation and abduction) was measured bilaterally by use of a handheld dynamometer in 501 competitive athletes (138 female and 363 male athletes) participating in various sports. During the sport season, ACL injury status was recorded, and injured athletes were further classified based on the mechanism of injury (noncontact vs contact). After the season, logistic regression was used to determine whether baseline hip strength predicted future noncontact ACL injury. Receiver operating characteristic (ROC) curves were constructed independently for each strength measure to determine the clinical cutoff value between a high-risk and low-risk outcome. RESULTS: A total of 15 noncontact ACL injuries were confirmed (6 females, 9 males), for an overall annual incidence of 3.0% (2.5% for males, 4.3% for females). Baseline hip strength measures (external rotation and abduction) were significantly lower in injured athletes compared with noninjured athletes (P = .003 and P < .001, respectively). Separate logistic regression models indicated that impaired hip strength increased future injury risk (external rotation: odds ratio [OR] = 1.23 [95% CI, 1.08-1.39], P = .001; abduction: OR = 1.12 [95% CI, 1.05-1.20], P = .001). Clinical cutoffs to define high risk were established as external rotation strength ≤20.3% BW (percentage of body weight) or abduction strength ≤35.4% BW. CONCLUSION: Measures of preseason isometric hip abduction and external rotation strength independently predicted future noncontact ACL injury status in competitive athletes. The study data suggest that screening procedures to assess ACL injury risk should include an assessment of isometric hip abduction and/or external rotation strength.
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BACKGROUND Mental health disorders and self-assessed mental health problems are common among students in tertiary education in Western countries. On average, one in three university students suffer from depressive symptoms and more female students are affected than males. Student mental health services are relevant settings for promoting mental health and preventing mental ill-health through interventions at the organizational-, group-and individual levels. However, student's problems differ across campuses and many intervention programs and policies are not based on the best available evidence. More over, sound interventions may remain without effect unless they are thoroughly implemented.
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Tendinopathy of the gluteus medius and gluteus minimus tendons is now recognized as a primary local source of lateral hip pain. The condition mostly occurs in mid-life both in athletes and in subjects who do not regularly exercise. Females are afflicted more than males. This condition interferes with sleep (side lying) and common weight-bearing tasks, which makes it a debilitating musculoskeletal condition with a significant impact. Mechanical loading drives the biological processes within a tendon and determines its structural form and load-bearing capacity. The combination of excessive compression and high tensile loads within tendons are thought to be most damaging. The available evidence suggests that joint position (particularly excessive hip adduction), together with muscle and bone elements, are key factors in gluteal tendinopathy. These factors provide a basis for a clinical reasoning process in the assessment and management of a patient presenting with localized lateral hip pain from gluteal tendinopathy. Currently, there is a lack of consensus as to which clinical examination tests provide best diagnostic utility. On the basis of the few diagnostic utility studies and the current understanding of the pathomechanics of gluteal tendinopathy, we propose that a battery of clinical tests utilizing a combination of provocative compressive and tensile loads is currently best practice in its assessment. Management of this condition commonly involves corticosteroid injection, exercise or shock wave therapy, with surgery reserved for recalcitrant cases. There is a dearth of evidence for any treatments, so the approach we recommend involves managing the load on the tendons through exercise and education on the underlying pathomechanics.
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Study design: Cross-sectional laboratory study. Objectives: To compare peak lower-limb, pelvis, and trunk kinematics and interjoint and intersegmental coordination in women with strong and weak hip muscle performance. Background: Persons with lower extremity musculoskeletal disorders often demonstrate a combination of weak hip musculature and altered kinematics during weight-bearing dynamic tasks. However, the association between hip strength and kinematics independent of pathology or pain is unclear. Methods: Peak hip extensor and abductor torques were measured in 150 healthy young women. Of these, 10 fit the criteria for the strong group and 9 for the weak group, representing those with the strongest and weakest hip musculature, respectively, of the 150 screened individuals. Kinematics of the hip, knee, pelvis, and trunk were measured during the stance phases of walking and rate-controlled hopping. Hip/knee and pelvis/trunk coordination were calculated using the vector coding technique. Results: There were no group differences in peak hip, knee, or pelvis kinematics. Participants in the weak group demonstrated greater trunk lateral bend toward the stance limb during hopping (P = .002, effect size [d] = 1.88). In the transverse plane, those in the weak group utilized less inphase coordination between the hip and the knee during walking (P = .036, d = 1.45) and more antiphase coordination between the hip and knee during hopping (P = .03, d = 1.47). Conclusion: In the absence of pain or pathology, poor hip muscle performance does not affect peak hip or knee joint kinematics in young women, but is associated with significantly different lower-limb and trunk/pelvis coordination during weight-bearing dynamic tasks. J Orthop Sports Phys Ther 2014;44(7):525-531. Epub 10 May 2014. doi:10.2519/jospt.2014.5028.
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Background: Strengthening exercise for gluteus medius (GMed) is an important management strategy for lower limb disorders such as osteoarthritis and patello-femoral syndrome, and exercises in functional positions are commonly prescribed. Electromyography (EMG) can be used to measure muscle activation to ascertain the extent of muscle recruitment during exercise. Objectives: To review the available evidence on the magnitude of GMed activation measured with EMG during therapeutic exercise. Methods: A structured review of studies which measured EMG magnitude of GMed during a range of therapeutic exercises was undertaken. Amplitude levels of GMed were reported as a percentage of maximum voluntary isometric contraction. Results: Fifteen studies were included. Most of these were conducted on asymptomatic volunteers, with three studies investigating individuals with knee or hip pathology. A wide range of exercises was investigated in both weightbearing (WB) and nonweightbearing (NWB) positions. In general, EMG activation was greater in WB positions but variation occurred across studies. Many exercises were below levels considered necessary for strength gains. Generally, methodological quality was good but there was variation in the reporting of technical aspects of the study. Many of the studies did not acknowledge the range of limitations of EMG in measuring muscle activation in therapeutic exercise. Conclusions: The results provide some information regarding GMed recruitment during exercise, although there were some discrepancies in results between studies which may be due to factors related to EMG measurement and recording as well as the execution of the exercise. Extrapolation of results to symptomatic populations in a clinical setting islimited.
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The purposes of this study were to compare lower-limb kinematics between genders, and determine the relationships among eccentric hip abductor and lateral rotator torques and lower-limb kinematics. The movements of the pelvis, femur, and knee were calculated for 16 women and 16 men during the single-leg squat. Eccentric hip abductor and lateral rotator torques were measured using an isokinetic dynamometer. The results showed that women had greater contralateral pelvic depression, femur adduction, and knee abduction than men. The eccentric hip abductor and lateral rotator torques were correlated with coronal plane femur and knee movements in the overall sample. When the genders were analyzed separately, it was observed that women with greater eccentric hip abductor torque exhibited less femur adduction and femur medial rotation, and greater knee adduction excursion. No significant relationship was observed between the isokinetic and kinematic variables in the male group. The differences between the genders help to explain the greater rate of knee disorders observed in women. Moreover, the eccentric hip abduction action seemed to be more important in women to control the lower-limb movements.
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Hip abductors are the most important muscles around the hip joint. It is therefore essential to assess their function in a valid and reliable way. Since the optimal body posture for the assessment of hip abductor strength is unknown, we tested the validity and reliability of unilateral hip abductor strength assessment in three different body positions. We hypothesized that the validity would be better in the side-lying position because of the consistent stabilization of the contralateral (untested) hip. Sixteen healthy subjects participated in two identical testing sessions. Unilateral isometric hip abductor muscle strength was measured, with use of a stabilized commercial dynamometer, with the subject in the side-lying, supine, and standing positions. Construct validity was based on concomitant recordings of gluteus medius electromyographic activity from the tested and contralateral hips. The body position permitting greater muscle activation and abductor strength on the tested hip, while minimizing muscle activation in the contralateral hip (that is, lower contralateral-to-tested electromyographic ratio), was considered the most valid. Coefficients of variation, the Bland and Altman limits of agreement, and intraclass correlation coefficients were calculated to determine test-retest reliability of hip abductor strength. Maximal hip abductor strength was significantly higher in the side-lying position compared with the standing and supine positions (p < 0.05). The contralateral-to-tested electromyographic ratio for the side-lying position was significantly lower than that for the supine and the standing position (p < 0.01). Test-retest reliability of strength measurements in terms of coefficients of variation (3.7% for side-lying, 6.1% for supine, and 4.2% for standing) and limits of agreement (+/-6.9% for side-lying, +/-8.4% for supine, and +/-7.5% for standing) was better in the side-lying position. All intraclass correlation coefficients were high to moderate (0.90 for side-lying, 0.83 for supine, and 0.88 for standing). The side-lying body position offers the most valid and reliable assessment of unilateral hip abductor strength.
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Gender differences in kinematics during running have been speculated to be a contributing factor to the lower extremity injury rate disparity between men and women. Specifically, increased non-sagittal motion of the pelvis and hip has been implicated; however it is not known if this difference exists under a variety of locomotion conditions. The purpose of this study was to characterize gender differences in gait kinematics and muscle activities as a function of speed and surface incline and to determine if lower extremity anthropometrics contribute to these differences. Whole body kinematics of 34 healthy volunteers were recorded along with electromyography of muscles on the right lower limb while each subject walked at 1.2, 1.5, and 1.8m/s and ran at 1.8, 2.7, and 3.6m/s with surface inclinations of 0%, 10%, and 15% grade. Joint angles and muscle activities were compared between genders across each speed-incline condition. Pelvis and lower extremity segment lengths were also measured and compared. Females displayed greater peak hip internal rotation and adduction, as well as gluteus maximus activity for all conditions. Significant interactions (speed-gender, incline-gender) were present for the gluteus medius and vastus lateralis. Hip adduction during walking was moderately correlated to the ratio of bi-trochanteric width to leg length. Our findings indicate females display greater non-sagittal motion. Future studies are needed to better define the relationship of these differences to injury risk.
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To determine if females with hip abductor weakness are more likely to demonstrate greater knee abduction during the stance phase of running than a strong hip abductor group. Observational prospective study design. University biomechanics laboratory. 15 females with weak hip abductors and 15 females with strong hip abductors. Group differences in lower extremity kinematics were analyzed using repeated measures ANOVA with one between factor of group and one within factor of position with a significance value of P < .05. The subjects with weak hip abductors demonstrated greater knee abduction during the stance phase of treadmill running than the strong group (P < .05). No other significant differences were found in the sagittal or frontal plane measurements of the hip, knee, or pelvis. Hip abductor weakness may influence knee abduction during the stance phase of running.
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Female athletes participating in high-risk sports suffer anterior cruciate ligament injury at a 4- to 6-fold greater rate than do male athletes. Prescreened female athletes with subsequent anterior cruciate ligament injury will demonstrate decreased neuromuscular control and increased valgus joint loading, predicting anterior cruciate ligament injury risk. Cohort study; Level of evidence, 2. There were 205 female athletes in the high-risk sports of soccer, basketball, and volleyball prospectively measured for neuromuscular control using 3-dimensional kinematics (joint angles) and joint loads using kinetics (joint moments) during a jump-landing task. Analysis of variance as well as linear and logistic regression were used to isolate predictors of risk in athletes who subsequently ruptured the anterior cruciate ligament. Nine athletes had a confirmed anterior cruciate ligament rupture; these 9 had significantly different knee posture and loading compared to the 196 who did not have anterior cruciate ligament rupture. Knee abduction angle (P<.05) at landing was 8 degrees greater in anterior cruciate ligament-injured than in uninjured athletes. Anterior cruciate ligament-injured athletes had a 2.5 times greater knee abduction moment (P<.001) and 20% higher ground reaction force (P<.05), whereas stance time was 16% shorter; hence, increased motion, force, and moments occurred more quickly. Knee abduction moment predicted anterior cruciate ligament injury status with 73% specificity and 78% sensitivity; dynamic valgus measures showed a predictive r2 of 0.88. Knee motion and knee loading during a landing task are predictors of anterior cruciate ligament injury risk in female athletes. Female athletes with increased dynamic valgus and high abduction loads are at increased risk of anterior cruciate ligament injury. The methods developed may be used to monitor neuromuscular control of the knee joint and may help develop simpler measures of neuromuscular control that can be used to direct female athletes to more effective, targeted interventions.
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Increased knee valgus predicts the risk of anterior cruciate ligament (ACL) injury, particularly in women. Reducing injury rates thus relies on detecting and continually evaluating people with relatively large valgus motions. To examine the potential of a two dimensional (2D) video analysis method for screening for excessive valgus. Ten female and 10 male National Collegiate Athletic Association basketball players had three dimensional (3D) knee valgus and two dimensional (2D) frontal plane knee angle quantified during side step, side jump, and shuttle run tasks. 3D valgus was quantified from external marker coordinates using standard techniques, and 2D data were obtained from both the frontal plane projections of these coordinates (2D-Mot) and manual digitization of digital video footage (2D-Cam). A root mean square (RMS) error was calculated between 2D-Mot and 2D-Cam data to evaluate the reliability of the latter. Correlations between 2D-Cam and 3D data (intersubject and intrasubject) were also conducted, and regression slope and r2 values obtained. 2D-Cam and 2D-Mot data were consistent for side step (RMS = 1.7 degrees) and side jump (RMS = 1.5 degrees) movements. Between subjects, 2D-Cam and 3D data correlated well for the side step (r2 = 0.58) and side jump (r2 = 0.64). Within subjects, 2D-Cam and 3D data correlated moderately for the side step (r2 = 0.25 (0.19)) and side jump (r2 = 0.36 (0.27)). The 2D-Cam method can be used to screen for excessive valgus in elite basketball players, particularly for movements occurring primarily in the frontal plane. This method may also be a useful training evaluation tool when large reductions in dynamic valgus motions are required.
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Study design: Observational prospective cohort study with 1-year follow-up. Objectives: To investigate the relationship between eccentric hip abduction strength and the development of patellofemoral pain (PFP) in novice runners during a self-structured running regime. Background: Recent research indicates that gluteal muscle weakness exists in individuals with PFP. However, current prospective research has been limited to the evaluation of isometric strength, producing inconsistent findings. Considering that hip muscles, including the gluteus maximus and medius, activate eccentrically to control hip and pelvic motion during weight-bearing activities such as running, the potential link between eccentric strength and PFP risk should be evaluated. Methods: Eight hundred thirty-two novice runners were included at baseline, and 629 participants were included in the final analysis. Maximal eccentric hip abduction strength was measured using a handheld dynamometer prior to initiating a self-structured running program. The diagnostic criteria to classify knee pain as PFP were based on a thorough clinical examination. Participants were followed for 12 months and training characteristics were gathered with a global positioning system. Results: Results from the unadjusted generalized linear regression model for cumulative risk at 25 and 50 km indicated differences in cumulative risk of PFP between high strength, normal strength, and low strength (P<.05), with higher strength associated with reduced risk. Conclusion: Findings from this study indicate that, among novice runners, a level of peak eccentric hip abduction strength that is higher than normal may reduce the risk of PFP during the first 50 km of a self-structured running program.
Article
Objective The purpose of this study was to examine the relationship between frontal plane kinematics of the single leg squat and strength of the trunk and hip in females. Participants Forty healthy females participated in this study. Methods An isometric “make” test using a dynamometer was used to assess peak force normalized to body weight for hip abduction, hip extension, hip external rotation, and a sidelying plank test. Two-dimensional software was used to analyze the frontal plane projection angle (FPPA) and pelvic angle during a single leg squat to 60°. Results All 4 strength factors were significantly correlated with the FPPA, ranging from r=0.396 to r=0.466. During multiple regression analysis, hip abduction strength was the greatest predictor of the variation in FPPA at r2=0.22, p =0.002. Thus, hip abduction strength accounted for 22% of the variation in the FPPA during the single leg squat. The only strength factor demonstrating a significant correlation with the pelvic angle was hip extension strength (r=0.550, p<0.001). Conclusion Clinicians should consider the role of the hip abductors, hip external rotators, hip extensors and core musculature on the impact on the FPPA during a single squat, with focus on the hip abductors.
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Abstract Lateral movements like cutting are essential in many team sport disciplines. The aim of the present study was to analyse adaptations in motor control in response to task unpredictability during lateral movement execution. Twelve subjects performed lateral jumps with different landing modalities (stable, sliding or counteracting) that were either known (predictable setting) or unknown (unpredictable setting) prior to movement execution. Results revealed that regardless of the landing modality, hip joint abduction was significantly greater in the unpredictable compared to predictable setting. Furthermore, during the sliding landing modality, hip flexion decreased from 211 ± 7° to 207 ± 7° and knee flexion decreased from 26 ± 4° to 24 ± 4° at the instant of ground contact in the unpredictable compared to predictable condition. During the stable landing modality, the knee joint abduction increased from -0.3 ± 6° to -3 ± 6° after initial ground contact in the unpredictable compared to predictable setting. The present results support our hypothesis that pre-programmed motor activity depends on the predictability of the landing modality during lateral movements. According to its adaptation in the frontal plane and in some extent in the sagittal plane, the hip joint seems to play the major role in the modulation of the pre-programmed activity for successful lateral jump execution in an unpredictable setting. However, these kinematic adaptations are concerning since these changes were associated with higher knee abduction during the stable landing modality and therefore with possible higher risk of injury.
Article
Hip muscle dysfunction may be associated with knee valgus that contributes to problems like patellofemoral pain syndrome. The purpose of this study was to (1) compare knee and hip kinematics and hip muscle strength and recruitment between "good" and "poor" performers on a single-leg squat test developed to assess hip muscle dysfunction and (2) examine relationships between hip muscle strength, recruitment and frontal plane knee kinematics to see which variables correlated with knee valgus during the test. Forty-one active women classified via visual rating as "good" or "poor" performers on the test participated. Participants completed 5-repetition single-leg squat tests. Isometric hip extension and abduction strength, gluteus maximus and gluteus medius recruitment, and 3-dimensional hip and knee kinematics during the test were compared between groups and examined for their association with frontal plane knee motion. "Poor" performers completed the test with more hip adduction (mean difference=7.6°) and flexion (mean difference=6.3°) than "good" performers. No differences in knee kinematics, hip strength or hip muscle recruitment occurred. However, the secondary findings indicated that increased medial hip rotation (partial r=0.94) and adduction (partial r=0.42) and decreased gluteus maximus recruitment (partial r=0.35) correlated with increased knee valgus. Whereas hip muscle function and knee kinematics did not differ between groups as we'd hypothesized, frontal plane knee motion correlated with transverse and frontal plane hip motions and with gluteus maximus recruitment. Gluteus maximus recruitment may modulate frontal plane knee kinematics during single-leg squats.
Article
As drop vertical jumps (DVJ) are widely used as a screening task, the assessment of the reliability of lower limb biomechanical parameters during DVJs is important. The aim of this study was to assess the reliability of the kinematic and kinetic peak values as well as of the waveforms for lower limb parameters obtained with the Liverpool John Moores University biomechanical model (LJMU-model) during performance of DVJs. The reliability was analysed by calculating the inter-trial, inter-session and inter-therapist errors of hip and knee joint parameters in a repeated-measures design including two therapists and a total of six sessions. The results showed inter-trial errors (o) that ranged from 1.1° - 3.5° for all peak kinematic parameters and from 3.6 N · m - 12.9 N · m for all peak kinetic parameters. The inter-session errors (o) of the peak values ranged from 1.9° - 5.7° for all angles and from 5.4 N · m - 19.8 N · m for the hip and knee joint moments in all planes. The inter-therapist error (o) of the peak values ranged from 2.7° - 6.4° for all angles and from 5.8 N · m - 22.4 N · m for all moments. The vast majority of the kinematic and kinetic peak parameters had o ≤ 2.0° and 4.3 N · m respectively suggesting a small extrinsic variability. Furthermore, the entire waveforms also showed a rather high inter-trial error relative to other types of variability. The present findings indicated that DVJs kinetics and kinematics show small extrinsic variability. The reported errors are useful for clinical interpretation processes of DVJ performance as screening task for injury risk and rehabilitation outcome taking into consideration the different types of measurement error over time.
Article
Context: Abnormal lower extremity kinematics during dynamic activities may be influenced by impaired gluteus maximus function. Objective: To examine whether hip-extensor strength and gluteus maximus recruitment are associated with dynamic frontal-plane knee motion during a jump-landing task. Design: Exploratory study. Setting: Biomechanics laboratory. Participants: 40 healthy female volunteers. Main outcome measures: Isometric hip-extension strength was measured bilaterally with a handheld dynamometer. Three-dimensional hip and knee kinematics and gluteus maximus electromyography data were collected bilaterally during a jump-landing test. Data were analyzed with hierarchical linear regression and partial correlation coefficients (α = .05). Results: Hip motion in the transverse plane was highly correlated with knee motion in the frontal plane (partial r = .724). After controlling for hip motion, reduced magnitudes of isometric hip-extensor strength (partial r = .470) and peak gluteus maximus recruitment (partial r = .277) were correlated with increased magnitudes of knee valgus during the jump-landing task. Conclusion: Hip-extensor strength and gluteus maximus recruitment, which represents a measure of the muscle's neuromuscular control, are both associated with frontal-plane knee motions during a dynamic weight-bearing task.
Article
[Purpose]: The aim of this study was to evaluate whether using a belt to restrain a hand-held dynamometer improves reliability of isometric lerg muscle stength measurements i healthy subjects. [Subjects]: Twenty to 44 healthy subjects participated in the test. [Methods]: Two raters, one man and one woman, used a hand-held dynamometer with or without a restraining belt to measure the isometric strengths of the following muscle groups: flexors, extensors, abductors, internal rotators and external rotators of the hip; flexors and extensors of the knee; and dorsiflexors and plantar flexors of the ankle. [Results]: The intraclass correlation coefficient, used to describe interrater agreement, ranged from 0.97 to 0.99 with the belt and from 0.21 to 0.88 without the belt. Pearson's correlation coefficient for measurements with versus without the belt ranged from 0.61 to 0.95 for the man and from 0.31 to 0.87 for the woman. [Conclusion]: The interrater reliability of isometric leg muscle strength measurements was improved by used of a belt to restrain the hand-held dynamometer.
Article
It has been postulated that subjects with weak hip abductors and external rotators may demonstrate increased knee valgus, which may in turn raise risk of injury to the lower extremity. Recent studies have explored the potential link between hip strength and knee kinematics, but there has not yet been a review of this literature. To conduct a systematic review assessing the potential link between hip-abductor or external-rotator strength and knee-valgus kinematics during dynamic activities in asymptomatic subjects. An online computer search was conducted in early February 2011. Databases included Medline, EMBASE, CINAHL, SPORTDiscus, and Google Scholar. Inclusion criteria were English language, asymptomatic subjects, dynamometric hip-strength assessment, single or multicamera kinematic analysis, and statistical analysis of the link between hip strength and knee valgus via correlations or tests of differences. Data were extracted concerning subject characteristics, study design, strength measures, kinematic measures, subject tasks, and findings with regard to correlations or group differences. Eleven studies were selected for review, 4 of which found evidence that subjects with weak hip abductors or external rotators demonstrated increased knee valgus, and 1 study found a correlation to the contrary. There is a small amount of evidence that healthy subjects with weak hip abductors and perhaps weak external rotators demonstrate increased knee valgus. However, due to the variation in methodology and lack of agreement between studies, it is not possible to make any definitive conclusions or clinical recommendations based on the results of this review. Further research is needed.
Article
The purpose of the present study was to examine the relationship between hip muscle strength (abduction and external rotation) and frontal-plane knee control during drop jumping in recreational female athletes. Thirty-three healthy young recreational female athletes were included. Maximal isometric hip abduction and external rotation torque were measured using hand-held dynamometry, and frontal-plane knee control during drop jumping was assessed using three-dimensional motion analysis. Frontal-plane knee control during drop jumping was expressed as the absolute (cm) and relative (cm/cm body height) change in distance between lateral knee markers from foot-ground contact to the time of minimal marker distance during the contact phase of the jump. Greater maximal external hip-rotation torque correlated significantly with greater absolute (r=0.48, P=0.005) and relative (r=0.43, P=0.012) change in knee marker distance during drop jumping. Maximal hip-abduction torque did not correlate with the absolute (r=0.18, P=0.31) or relative (r=0.19, P=0.29) change in knee marker distance during drop jumping. Contrary to our expectations, greater maximal external hip-rotation torque was related to greater change in knee marker distance during drop jumping (reduced frontal-plane knee control) in recreational female athletes.
Article
Unlabelled: During the last decade, there has been a growing body of literature suggesting that proximal factors may play a contributory role with respect to knee injuries. A review of the biomechanical and clinical studies in this area indicated that impaired muscular control of the hip, pelvis, and trunk can affect tibiofemoral and patellofemoral joint kinematics and kinetics in multiple planes. In particular, there is evidence that motion impairments at the hip may underlie injuries such as anterior cruciate ligament tears, iliotibial band syndrome, and patellofemoral joint pain. In addition, the literature suggests that females may be more disposed to proximal influences than males. Based on the evidence presented as part of this clinical commentary, it can be argued that interventions which address proximal impairments may be beneficial for patients who present with various knee conditions. More specifically, a biomechanical argument can be made for the incorporation of pelvis and trunk stability, as well as dynamic hip joint control, into the design of knee rehabilitation programs. Level of evidence: Aetiology/therapy, level 5.
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Hip strength assessment plays an important role in the clinical examination of the hip and groin region. The primary aim of this study was to examine the absolute test-retest measurement variation concerning standardized strength assessments of hip abduction (ABD), adduction (ADD), external rotation (ER), internal rotation (IR), flexion (FLEX) and extension (EXT) using a hand-held dynamometer. Nine subjects (five males, four females), physically active for at least 2.5 h a week, were included. Twelve standardized isometric strength tests were performed twice with a 1-week interval in between by the same examiner. The test order was randomized to avoid systematic bias. Measurement variation between sessions was 3-12%. When the maximum value of four measurements was used, test-retest measurement variation was below 10% in 11 of the 12 individual hip strength tests and below 5% in five of the 12 tests. No systematic differences were present. Standardized strength assessment procedures of hip ABD, ER, IR, FLEX, with test-retest measurement variation below 5%, hip ADD below 6% and hip EXT below 8%, make it possible to determine even small changes in hip strength at the individual level.
Article
There has been an intensive research effort directed at determining the cause of non-contact anterior cruciate ligament (ACL) injury over the past decade, but few studies have reported data on the incidence of ACL and other knee ligament injury in the general population. New Zealand's no-fault injury compensation data provides a national injury resource of data on claims for knee ligament injury. The goal of this paper was to provide a descriptive epidemiology of knee ligament injury in this country. Data were obtained for knee ligament injuries between 1 July 2000 and 30 June 2005. Injuries were categorised as non-surgical (NS), ACL surgeries (ACLS) and other knee ligament surgeries (OKLS). Incidence rates per 100,000 person-years were computed using population estimates. Costs and number of treatment/rehabilitation visits were obtained as an indication of severity. The incidence rate per 100,000 person-years was 1147.1 for NS, 36.9 for ACLS and 9.1 for OKLS. Males had a higher incidence rate than females for NS, ACLS, and OKLS. The mean (and median) number of treatment visits were NS: 6.6 (4), ACLS: 27.1 (24), and OKLS: 31.3 (24). The mean (median) treatment costs of these injuries were NS $885 ($129), ACLS $11,157 ($8574), and OKLS $15,663 ($8054). Analysis of injury descriptions for ACLS injuries indicated that 58% involved a non-contact mechanism of injury. These data underscore the high level of short-term disability associated with knee ligament injuries, especially ACL injuries that require surgery.
Article
The purpose of this study was to develop a clinically useful method of assessing the strength of the hip musculature and to develop a normal data base with this technique. The strength of 72 subjects aged 20-81 years (37 women and 35 men) was measured through the use of a modified Cybex II with an upright stabilization frame for testing sagittal and frontal plane motions; transverse plane motions of internal and external rotation were tested in the seated position. The subjects were tested at multiple isokinetic speeds and isometric angles. Regardless of age or gender, hip extensors were the strongest muscle group, following by flexors, adductors, abductors, and rotators. As the velocity of exercise increased, the magnitude of the torques produced decreased. Demographically, younger men produced the greatest torques and older women the lowest. The strength values of older men and younger women were similar. The results have clinical implications for objective assessment of strength in pathologic patient populations.
Article
This study evaluated kinematic, vertical ground reaction forces, and strength variables in healthy collegiate female basketball, volleyball, and soccer players compared with matched male subjects. Thirty athletes did single-leg landing and forward hop tasks. An electromagnetic tracking device synchronized with a force plate provided kinematic data and vertical ground reaction force data, respectively. Maximum angular displacement and time to maximum angular displacement kinematic variables were calculated for hip flexion, abduction, rotation, knee flexion, and lower leg rotation. Vertical ground reaction force data normalized to body mass provided impulse, maximum force, time to maximum force, and stabilization time variables. An isokinetic device measured quadriceps and hamstring peak torque to body mass at 60 degrees /second. With both tasks, females had significantly less knee flexion and lower leg internal rotation maximum angular displacement, and less knee flexion time to maximum angular displacement than males. For the single-leg land, females had significantly more hip internal rotation maximum angular displacement, and less lower leg internal rotation time to maximum angular displacement than males. For the forward hop, females had significantly more hip rotation time to maximum angular displacement than males. Females also had significantly less peak torque to body mass for the quadriceps and hamstrings than males. Weaker thigh musculature may be related to the abrupt stiffening of the knee and lower leg on landing in females.
Quantifying heterogeneity in a meta-analysis
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Higgins, J. P. T. & Thompson, S.G. (2002) Quantifying heterogeneity in a meta-analysis.
Relationship between knee valgus, hip-muscle strength, and hip muscle 623 recruitment during a single-limb step-down
J.W. (2009). Relationship between knee valgus, hip-muscle strength, and hip muscle 623 recruitment during a single-limb step-down. Journal of Sport Rehabilitation, 18(1):104117.