BACKGROUND: Dynamic knee valgus (DKV) is a risk factor for non-contact anterior cruciate ligament (ACL) injuries. Understanding the changes in the electromyographic activity of the lower extremity muscles in individuals with DKV helps trainers design ACL injury prevention exercises. Therefore, the present meta-analysis aimed to investigate the muscle activation of the lower limb muscles in individuals with DKV during single-leg and overhead squats.
METHODS: Articles with titles, abstracts, and full texts were searched and screened independently by two reviewers in the Web of Science, Scopus, PubMed, and Google Scholar databases, without restrictions on publication date and in English using specified keywords from their inception to January 5, 2024. The quality of articles was evaluated using a modified version of the Downs and Black quality checklist. This meta-analysis used mean difference (MD) to compare the muscle activity patterns between individual with DKV and healthy individuals. Heterogeneity was detected using I-square (I2) test.
RESULTS: In total, four papers with 130 participants were included in the study. Evidence showed a significant difference between the DKV group and the healthy group regarding the activities of the adductor magnus (MD: 6.25, P < 0.001), vastus medialis (MD: 13.23, P = 0.002), vastus lateralis (MD: 11.71, P = 0.004), biceps femoris (MD: 3.06, P = 0.003), and tibialis anterior muscles (MD: 8.21, P = 0.02). Additionally, muscle activity in the DKV group was higher than that in the healthy group.
CONCLUSIONS: This meta-analysis reveals distinct muscle activation patterns in individuals with dynamic knee valgus (DKV), with increased activity in key muscles suggesting compensatory responses. These findings underscore the need for targeted rehabilitation to address muscle imbalances and improve knee stability.

BACKGROUND: Patellofemoral pain (PFP) patients often show an altered lower limb alignment during the single-leg squat (SLS). There is evidence that proximal and distal-to-the-knee muscle alterations can modify the lower limb alignment in PFP patients. However, we observed a lack of studies investigating the possible association between the thickness and strength of proximal and distal-to-the-knee muscles and lower limb alignment during SLS in women with PFP. Therefore, this study aimed to investigate the association between the thickness and strength of lower limb muscles and dynamic knee valgus (DKV) during SLS in women with PFP.
METHODS: Cross-sectional study, where fifty-five women with PFP were submitted to the following evaluations: (1) muscle thickness (MT) of Gluteus Medius (GMed), Gluteus Maximus (GMax), Vastus Lateralis (VL), and Tibialis Anterior (TA); (2) isometric peak torque of hip abductors, hip external rotators, knee extensors, and foot inversors; and (3) DKV during SLS.
RESULTS: There was a significant negative association between GMax\'s MT and DKV (r = -0.32; p = 0.01), and between TA\'s MT and DKV (r = -0.28; p = 0.03). No significant correlations were observed between isometric torques and DKV. Regression analysis found that GMax\'s MT explained 10% of the DKV\'s variance during SLS.
CONCLUSIONS: Poor lower limb alignment during SLS is weakly associated with proximal and distal-to-the-knee muscle thicknesses, with no association with isometric torque in PFP women.
CONCLUSIONS: Our results suggest that other factors besides strength and muscle thicknesses may explain and improve lower limb alignment in women with PFP.

OBJECTIVE: The aim of the present study is to 1) the effect of exacerbating patellofemoral pain (PFP) on dynamic knee valgus (DKV) 2) the relationship between exacerbating PFP and DKV in females with patellofemoral pain.
METHODS: Cross-sectional study.
METHODS: Sixty women with PFP were recruited from the orthopedic clinics. We evaluated pain intensity and DKV in two conditions without (condition 1) and with (condition 2) PFJ loading during the single-leg squat (SLS) task. The MANOVA test was used to compare pain intensity and DKV angle between the two conditions. Furthermore, the Pearson correlation was used to examine the correlation between pain intensity with DKV angle.
RESULTS: The MANOVA analysis showed that pain intensity (P < 0.000, η2 = 0.623) and DKV angle (P < 0.000, η2 = 0.544) with a medium effect size significantly increased after PFJ loading. Furthermore, an excellent positive correlation was observed between an increase in pain intensity and DKV angle (P < 0.000, r = 0.840).
CONCLUSIONS: It seems that after the PFJ loading protocol and the subsequent pain exacerbation, the neuromuscular biomechanics of the lower limb are deficits. As a result, the stabilizing muscles activation decreases and increases the lower limb movement in the frontal plane.

UNASSIGNED: The analysis of movement quality is important for better exercise prescription. This study tested the reproducibility of a protocol for remote assessment of dynamic knee alignment using images taken by patients.
UNASSIGNED: Thirteen women filmed themselves performing single-leg squats on two days at a 15-day interval. Three raters measured the knee frontal plane projection angle using the resultant images.
UNASSIGNED: Two participants (15.4%) were excluded for not performing the protocol correctly. The intraclass correlation coefficient was between 0.880 and 0.999 for the intra-rater comparison, and between 0.817 and 0.987 for the inter-rater comparison.
UNASSIGNED: The success of the protocol in 84.6% of participants and the excellent reproducibility suggest that the methodology of analyzing patient-captured cell phone images might be a plausible alternative for remote evaluation of dynamic knee alignment.

UNASSIGNED: Fatigue can decrease knee stability and increase the injury risk. However, fatigue is rarely being applied throughout movement analysis. The aim of this study was to investigate if the knee stability throughout SLDLs differ between cyclic and acyclic sports, before and after fatigue in general, and between the dominant and non-dominant leg of soccer players.
UNASSIGNED: A total of 43 active male (n = 34) and female (n = 9) athletes (age: 26.5 ± 7.2) participated in this study with a pre-post-design. Subjects performed a single leg drop landing (SLDL) from a plyobox. For each leg, the two-dimensional frontal plane projection angle (FPPA) was analyzed. After pretesting the shuttle run test was performed until exhaustion, before repeating the measurements.
UNASSIGNED: ANOVA with repeated measures was applied and identified no significance difference for the FPPA between cyclic and acyclic sports (F = 0.98, p = 0.33), a significant difference before and after fatigue (F = 12.49, p = 0.002) and no significant difference between the dominant and non dominant leg of soccer players (F = 4.35, p = 0.26).
UNASSIGNED: Fatigue seems to be able to have a significant influence on knee stability in the frontal axis. Therefore, fatigue should be included in motion analysis for injury prevention and return to play tests because during this physical state most injuries happen.

A functional biomechanics garment (FBG) may help to prevent injury by improved kinematics during motion such as single leg drop landing (SLDL). The purpose of this study was to investigate the effects of the FBG on the biomechanics of SLDL.
Seventeen female university basketball players participated. Characteristics of the FBG were designed based on biomechanics during weight-loaded performance of human movement. The average values of lower limb kinematics and kinetics in the sagittal and frontal planes from 3 SLDL with and without FBG were measured and compared.
The maximum varus angle of the knee showed a significant difference between the use of FBG (15.3 ± 15.1°) and without the use of FBG (5.9 ± 15.4°), the flexion angular displacement of the hip (with FBG, 21.5 ± 8.1°; without FBG, 24.0 ± 6.7°) between with and without FBG. The moment of the hip with FGB (1.1 ± 0.6 Nm) was significantly smaller than without FGB (1.4 ± 0.8 Nm).
Regarding function of the FBG, the rigid part of the hip could counter the excessive adduction and flexion of the hip, and the elastic part of the thigh could support the varus moment when the elastic part stretched. Therefore, the subjects with FBG could control the frontal motion of the knee, which has a risk of knee injury, such as the dynamic valgus of the knee during the SLDL.
Use of the FBG decreases dynamic knee valgus, which reduces risk of knee injury.

BACKGROUND: Dynamic knee valgus (DKV) is a multi-planar faulty movement pattern that can cause faulty postural control. The primary objective of this study is to investigate the differences in postural sway (PS) between individuals aged 18-30 years old diagnosed with and without DKV.
METHODS: In this cross-sectional study, 62 students (39 males and 23 females) with and without DKV (age: 24.58 ± 2.63 years) were selected and assigned to two groups by conducting the single-leg squat test in the screening stage. The Biodex balance system was then employed to compare the two groups in PS. Mann-Whitney U test was conducted to compare the groups in PS (p ≤ 0.05).
RESULTS: The study\'s findings indicate that individuals with DKV did not exhibit any significant differences, compared to those without, about the anterior-posterior stability index (with p values for both static and dynamic situations at 0.309 and 0.198, respectively), medial-lateral stability index (with p values for both static and dynamic situations at 0.883 and 0.500, respectively), and overall stability index (with p values for both static and dynamic situations at 0.277 and 0.086, respectively).
CONCLUSIONS: Though several possible factors could contribute to the lack of significant differences in postural sway between individuals with and without DKV, such as measurement tool differences, variable sensitivity in postural stability tests, and differences in movement variability and test stance, we recommend analyzing postural sway in more functional tasks and with different methodological patterns in future studies. Such research could help develop targeted interventions for individuals with DKV and offer a better understanding of the relationship between postural control and DKV.

The aim of this study was to compare the muscle activity of the gluteus medius (GMe), gluteus maximus (GMa), biceps femoris (BF), vastus lateralis (VL), vastus medialis (VM) and erector spinae (ES) as well as medial knee displacement (MKD) while using varying stiffness resistance bands (red: 1.68 kg; black: 3.31 kg; gold: 6.44 kg) during a barbell back squat (BBS) among males and females. A total of 23 (females: 11) resistance trained people were recruited for this study. Muscle activity was measured using electromyography, and motion capture cameras tracked lower-limb kinematics and MKD. Three resistance bands were placed at the distal end of the femur while performing a BBS at their 85% repetition maximum (RM). Parametric and non-parametric statistical analyses were conducted with the alpha level of 0.05. The gold resistance band resulted in a smaller knee-width-index value (i.e., greater MKD) compared to other bands (p < 0.01). Males exhibited less MKD compared to females during the BBS for each resistance band (p = 0.04). Males produced greater VL activity when using the black and gold resistance bands during the BBS (p = 0.03). When using a gold resistance band, the GMe muscle activation was higher compared to other resistance bands (p < 0.01). VM muscle activity was reduced when using a gold resistance band compared to no band condition (p < 0.01). BF (p = 0.39) and ES (p = 0.88) muscle activity did not change when using different resistance bands. As a result, females may be at a biomechanical disadvantage when using resistance bands compared to males while performing the BBS hindering them from optimal performance.

BACKGROUND: The performing of jump and landing in futsal simultaneous with divided attention is one of the most common mechanisms of non-contact anterior cruciate ligament (ACL) injury. Neuromuscular training has effectively reduced the risk of ACL injury, but the effect of neurocognitive training has received less attention. This study investigated the effect of combining 8 weeks of neuromuscular training with dual cognitive tasks on the landing mechanics of futsal players with knee ligament dominance defects.
METHODS: Thirty male futsal players (mean ± SD: age: 21.86 ± 3.27 years) with knee ligament dominance defects were purposefully identified by the tuck jump test and were randomly divided into the intervention and the control group. The intervention group performed dual task (DT) training for three weekly sessions for 8 weeks and 60 min each, while the control group only did activities of daily living. During the drop vertical jump test, 2D landing kinematics in two moments of initial contact (IC) and full flexion (FF) were assessed. Data were analyzed by means of 2 × 2 repeated measures ANOVA followed by post hoc comparison (Bonferroni) at the significance level of (α ≤ 0.05).
RESULTS: A significant improvement was observed in the intervention group compared to the control group for the dynamic knee valgus at IC (F1,28 = 6.33; P = 0.02, ES = 0.31) and FF (F1,28 = 13.47; P = 0.003, ES = 0.49), knee flexion at IC (F1,28 = 20.08; P = 0.001, ES = 0.41) and FF (F1,28 = 13.67; P = 0.001, ES = 0.32), ankle dorsiflexion at IC (F1,28 = 37.17; P = 0.001, ES = 0.72) and FF (F1,28 = 14.52; P = 0.002, ES = 0.50), and trunk flexion at FF (F1,28 = 20.48; P = 0.001, ES = 0.59) angles. Changes in the trunk flexion at IC (F1,28 = 0.54; P = 0.47, ES = 0.03) and trunk lateral flexion at IC (F1,28 = 0.006; P = 0.93, ES = 0.00) and FF (F1,28 = 2.44; P = 0.141, ES = 0.148) angles were not statistically significant.
CONCLUSIONS: DT training compared to the control group improved landing mechanics in futsal players with knee ligament dominance defects.
BACKGROUND: Current Controlled Trials using the IRCT website with ID number IRCT20210602051477N1 prospectively registered on 20/06/2021.

Anterior cruciate ligament (ACL) injuries are caused by both contact and non-contact injuries. However, it can be claimed that non-contact ones account approximately for 70% of all cases. Thus, several authors have emphasized the role of reduction of muscle strength as a modifiable risk factor referred to non-contact ACL injury, with the latter being targeted by specific training interventions.The present paper wants to review the available literature specifically on the relationship between dynamic knee valgus, gluteal muscles (GM) strength, apart from the potential correlation regarding ACL injury.After a research based on MEDLINE via PubMed, Google scholar, and Web of Science, a total of 29 articles were collected and thus included.Additionally, this review highlights the crucial role of gluteal muscles in maintaining a correct knee position in the coronal plane during different exercises, namely walking, running, jumping and landing.