The relationship of foot and ankle mobility to the frontal plane projection angle in asymptomatic adults

Determinants of Achilles tendon thickness and their influence on knee function and foot alignment in knee osteoarthritis

Knee osteoarthritis (OA) significantly impacts the quality of life of individuals globally. However, the interconnections between Achilles tendon thickness, knee symptoms/functions, and foot alignment remain understudied in knee OA patients. This study determines the relationships between Achilles tendon thickness (ATT), knee symptoms/functions, and foot alignment in knee OA patients, considering their interconnected biomechanical nature. In a cross-sectional analysis involving 122 knee OA patients, Knee injury and Osteoarthritis Outcome Score (KOOS) assessed knee function and symptoms. Forefoot, midfoot, and rearfoot alignment were measured using hallux valgus angle, navicular/foot ratio, and rearfoot angle. The navicular/foot ratio represented the ratio of navicular height to total foot length. ATT was measured using a digital calliper. Pearson correlations and stepwise multiple linear regression models were employed to explore relationships and determinants. Out of 122 participants, 88 (72.1%) were females. ATT correlated significantly with ankle range of motion, forefoot alignment, and midfoot alignment. In stepwise multivariable regression, ankle range of motion, navicular/foot ratio, and age were significantly associated with ATT (adjusted R2 = 0.44). Similarly, KOOS-Symptoms scores were linked to the OA severity, navicular/foot ratio, ankle range of motion, gastrocnemius strength, and age (adjusted R2 = 0.22). KOOS-Function scores were significantly associated with knee OA severity, gastrocnemius strength, ankle range of motion, and age (adjusted R2 = 0.19). Midfoot alignment was significantly associated with ATT and knee symptoms in patients with Knee OA. This suggests potential benefits of interventions targeting both Achilles tendon properties and foot alignment for improved knee OA outcomes.

Lower limb muscles' thicknesses are weakly associated with dynamic knee valgus during single-leg squat in women with patellofemoral pain

INTRODUCTION

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.

DISCUSSION

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.

CONCLUSION

Our results suggest that other factors besides strength and muscle thicknesses may explain and improve lower limb alignment in women with PFP.

Relationship between ankle dorsiflexion range of motion and sprinting and jumping ability in young athletes

OBJECTIVES

To investigate the relationship between predicted risk of injury based on the dichotomous classification of the weight-bearing lunge (WBL) test scores and variables related to jumping and sprinting ability in young athletes. Furthermore, to compare the impact of the classical dichotomous classification versus a more specific quartile subdivision of the WBL test scores on the explored variables.

DESIGN

Cross-sectional study.

PARTICIPANTS

125 healthy athletes (mean age 10.38 (SD = 2.28) years) were recruited.

MAIN OUTCOME MEASURES

Ankle dorsiflexion was evaluated with the WBL test, jumping distance with the standing long jump (SLJ) test, and maximal running speed with the 14-m and 28-m sprint test.

RESULTS

Athletes with WBL test scores lower than 10 cm exhibited significantly poorer results for the SLJ test as well as lower 14-m and 28-m sprint times than those with WBL test scores higher than 10 cm (p < 0.05). Likewise, when WBL test scores were subdivided by quartiles, a positive trend between range of motion and improved performance was shown.

CONCLUSIONS

Reduced ankle dorsiflexion mobility may affect sprinting and jumping ability in young athletes. In addition, a more detailed classification of ankle restriction by quartiles is proposed in this study in order to prevent injury and enhance athletic performance.

Effect of Sex and Lateral Ankle Sprain History on Dorsiflexion Range Of Motion Asymmetry During the Weight Bearing Lunge Test

Background

Reduced dorsiflexion range of motion (DFROM) which is commonly seen following lateral ankle sprain (LAS) has the potential to influence lower extremity biomechanics which have been linked to increased injury risk in the female athlete. Current research on the effect of sex and LAS history on DFROM is limited.

Hypothesis/Purpose

This study had three aims 1) to determine the effect of sex, leg dominance and LAS history on DFROM, 2) to determine the effect of sex and LAS history on magnitude of DFROM symmetry and 3) to examine the association of sex on direction (whether dominant or non-dominant limb had the higher DFROM) of symmetry.

Study Design

Cross-Sectional Study.

Methods

DFROM was measured bilaterally in 105 recreational athletes all participating in multidirectional sports using the tape measurement method during the weight bearing lunge test (WBLT). A mean of three measurements was used for analysis. A 3-way mixed ANOVA was carried out to determine the interaction between sex, LAS history and leg dominance on DFROM and a 2-way ANOVA for the effect of sex and LAS history on asymmetry. A chi-square test was used to determine the association of sex and direction of asymmetry.

Results

The results indicate no significant effect of sex, LAS history, and leg dominance on DFROM (p=0.65). Main effects were significant for sex and LAS on DFROM. The mean asymmetry for all participants was reported as 12.25±14.76cm. No significant effect of sex and LAS history on magnitude of asymmetry was reported. There was a significant association of sex and direction of asymmetry (χ2(1) = 11.26, p = 0.00). Sixty-five-point two percent of males were shown to have higher DFROM of their non-dominant limb compared to 75% of females who were higher in their dominant limb.

Conclusion

Findings from this study suggest that DFROM is affected by sex and LAS history. While females have increased DFROM compared to males, those with LAS history are more likely to have a decreased DFROM on the involved side. The results also indicate that interlimb asymmetries in DFROM are present in athletes, therefore practitioners should exercise caution when using bilateral comparisons in injury and return to play assessments.

Level of Evidence

2b.

The effects of static and dynamic stretching on deep fascia stiffness: a randomized, controlled cross-over study

AIM

Previous stretching studies mostly investigated effects on the skeletal muscle but comprehensive explorations regarding the role of the connective tissue are scarce. Since the deep fascia has been demonstrated to be sensitive to mechanical tension, it was hypothesized that the fascia would also respond to stretching, contributing to enhanced range of motion (ROM).

METHODS

Forty (40) recreationally active participants (male: n = 25, female: n = 15) were included in the randomized controlled cross-over trial and allocated to different groups performing 5 min static (STAT) or dynamic (DYN) plantar flexor stretching or control condition (CC) in a random order. Pre- and immediately post-intervention, muscle and fascia stiffness, as well as muscle and fascia thickness were measured using high-resolution ultrasound and strain elastography. ROM was assessed in the ankle joint via the knee to wall test (KtW) and goniometer.

RESULTS

STAT reduced both, muscle and fascia stiffness (d = 0.78 and 0.42, p < 0.001, respectively), while DYN did not reduce stiffness compared to the control condition (p = 0.11-0.41). While both conditions showed significant increases in the KtW (d = 0.43-0.46, p = 0.02-0.04), no significant differences to the CC were observed for the isolated ROM testing (p = 0.09 and 0.77). There was a small correlation between fascia stiffness decreases and ROM increases (r = - 0.25, p = 0.006) but no association was found between muscle stiffness decreases and ROM increases (p = 0.13-0.40).

CONCLUSION

Our study is the first to reveal stretch-induced changes in fascia stiffness. Changes of fascia`s but not muscle`s mechanical properties may contribute to increased ROM following stretching.

Prevention of Secondary Injury after Anterior Cruciate Ligament Reconstruction: Relationship between Pelvic-Drop and Dynamic Knee Valgus

(1) Background: Optimal neuromuscular, Lumbo-Pelvic-Hip Complex, and lower extremity control are associated with decreased risk factors for secondary anterior cruciate ligament (ACL) injury. This study aimed to analyze any asymmetries and malalignments in the Lumbo-Pelvic-Hip Complex and the lower limbs at 6 months after ACL reconstruction (ACLR). (2) Methods: We conducted an exploratory retrospective observational single-center study in patients during the outpatient postoperative rehabilitation program at ICOT (Latina, Italy). From January 2014 to June 2020, 181 patients were recruited, but only 100 patients (86 male 28 ± 0.6 years, 178 ± 0.5 height; 14 female 24 ± 2.0 years, 178 ± 3.0 height) were eligible for the inclusion criteria and studied 6 months after ACL reconstruction surgery. (3) Statistical analysis: Student's t-tests and Pearson's product-moment correlation coefficient were used to determine significant differences between affected and non-affected limbs and variables' association. (4) Results: The study shows a decrease in neuromuscular control of the Lumbo-Pelvic-Hip Complex and dynamic adaptive valgus of the knee at 6 months after ACLR (mean difference between pathological and healthy limb of dynamic adaptive valgus was -10.11 ± 8.19° 95% CI -14.84 to -9.34; mean value was 16.3 ± 6.8° 95% CI 14.04 to 18.55 for healthy limb and 4.2 ± 3.1° 95% CI 3.15 to 5.21 for pathological limb, p < 0.0001). The results also showed a relationship between dynamic adaptive valgus and contralateral pelvic drop (r = 0.78, 95% CI 0.62 to 0.88, magnitude of correlation very large). (5) Conclusions: The analysis showed an associative correlation between decreased postural control of the pelvic girdle and dynamic adaptive valgus of the knee in 38% of patients; this study highlights the usefulness of the Single-Leg Squat Test (SLST) as a clinical/functional assessment to evaluate the rehabilitation process and as a preventive tool to reduce the risk of second ACL injuries during the return to sport.

Análisis cinemático del ángulo de proyección frontal de rodilla en 2D: enfoque metodológico

La evaluación cinemática del comportamiento del miembro inferior en tres dimensiones (3D) requiere el uso de alta tecnología, formación especializada y laboratorios que no se ajustan a las demandas del ámbito clínico y deportivo. La valoración del APFR (ángulo de proyección frontal de rodilla)en dos dimensiones (2D) ha mostrado consistentemente su validez, objetividad y confiabilidad al ser comparada con la metodología de análisis en 3D para la detección del valgo dinámico asociado al incremento de torques externos de aducción y rotación interna de cadera durante la ejecución de tareas funcionales que exigen control muscular excéntrico. El valgo dinámico ha mostrado ser un predictor de lesión del ligamento cruzado anterior y de síndrome de dolor patelofemoral, especialmente en mujeres. La detección oportuna y el seguimiento del comportamiento cinemático con instrumentos de bajo costo, poca complejidad y un nivel de experticia básico utilizando análisis en 2D, se perfila como estrategia de valoración importante en el entrenamiento deportivo y el abordaje clínico para la prevención y rehabilitación de lesiones de rodilla asociados a estos desórdenes del movimiento. Por tanto, esta revisión narrativa pretende proveer de conocimientos esenciales para la correcta valoración, interpretación y análisis del APFR en Fisioterapeutas y Profesionales del Deporte.

The relationship between ankle dorsiflexion range of motion, frontal plane projection angle, and patellofemoral pain syndrome

BACKGROUND

Ankle range of motion abnormalities have been often linked with alteration in knee kinematics leading to the development of patellofemoral pain syndrome (PFPS). Literature exploring the relationship between ankle dorsiflexion range of motion (DF ROM) and knee kinematics during functional tasks is scanty. This study aims to assess the relation between ankle DF ROM and frontal plane projection angle (FPPA), one of the knee kinematic variables, in individuals with and without PFPS during a step-down test.

METHODS

This is a case-control study in which seventy PFPS patients and other 70 asymptomatic control subjects had their ankle DF ROM measured using an inclinometer with the knee flexed and extended. Their FPPA angles were measured using Kinovea software while doing the step-down test.

RESULTS

When the two groups were compared, ankle DF ROM measured with the knee flexed was higher in the control group (33.15 ± 4.96) than in the PFPS group (30.20 ± 6.93) (p = 0.03). In both the PFPS group and the control group, the correlation between FPPA and ankle DF ROM with the knee flexed was statistically insignificant (p = 0.075 and 0.323 respectively).

CONCLUSION

Decreased ankle DF ROM can be one of the contributing factors to the development of PFPS in the context of greater dynamic knee valgus.

Dynamic knee valgus prevalence in children and its association with pain intensity, foot mobility, and sex- A cross-sectional study

Introduction

Knee pain can impact the performance of activities and sports participation in children. Dynamic knee valgus is a movement pattern commonly related to health conditions that may be associated with sex and foot kinematics in children.

Objective

To assess the prevalence of dynamic knee valgus and its relationship with foot mobility, sex, and knee pain in children.

Method

A cross-sectional observational study was carried out with 144 children (10-18 years old). The pain level was investigated using the Visual Analog Pain Scale and categorized into no pain/minor pain (≤2 cm), moderate pain (3-4,9 cm), and severe pain (≥5.0 cm). Foot mobility was assessed using the adapted navicular drop test and categorized into poor/adequate foot mobility (0.0 cm-0.9 cm) and greater foot mobility (≥1.0 cm). The dynamic knee valgus presence was checked using the step-down test. The association analysis was performed using simple tabulation considering the cluster effect. The Prevalence Ratios and the respective confidence intervals (95%) were estimated from Multiple Poisson Regression with robust variance. A significance level of 5% was adopted.

Results

The dynamic knee valgus prevalence was 26.3% and 26.9% in the right and left lower limbs, respectively. Females presented greater dynamic knee valgus frequency in the left lower limb than males. The dynamic knee valgus presence in males was associated with foot mobility in right (p = 0.001) (Prevalence Ratio: 9.33 Confidence Interval: 2.93-29.72) and left lower limbs (p = 0.003) (Prevalence Ratio: 6.25 Confidence Interval: 1.7-22.62).

Conclusion

Male and female children showed different relationships of the analyzed factors, suggesting that characteristics related to sex may impact the aspects linked to dynamic knee in children.

Depth of single-leg squat influences the two-dimensional analysis of knee, hip, and pelvis frontal plane motion in pain-free women

BACKGROUND

The single-leg squat (SLS) is often used to measure two-dimensional frontal plane motion; however, there is a variability in the SLS depth across studies.

RESEARCH QUESTION

Are knee abduction (KABD), hip adduction (HADD), pelvic drop (PD), and lateral trunk flexion (LTF) angles different at greater knee flexion angles during a SLS?

METHODS

Twenty pain-free females (age=22.3 ± 1.1 years, height=1.68 ± 0.06 m, mass=63.1 ± 11.7 kg) participated in this cross-sectional study. Participants performed five SLSs to the lowest depth comfortable, keeping pace with a metronome, while being video recorded in the frontal and sagittal planes. The middle three SLSs were used for analysis. KABD, HADD, PD, and LTF angles were measured at 30º, 45º, 60º, 75º, and 90º of knee flexion using extracted images. Linear mixed model analyses were used to compare across knee flexion angles and clinical significance was determined by comparing angle changes to the standard error of measurement (SEM).

RESULTS

We observed significant differences for KABD (F=14.69, p < .001), HADD (F=46.29, p < .001), and PD (F=27.27, p < .001) among knee flexion angles. Post-hoc analyses revealed that KABD significantly increased at every increase of knee flexion angle (p ≤ .05, d=0.54-1.95), as did HADD (p ≤ .05, d=0.64-3.85) and PD (p ≤ .05, d=0.61-3.03). Changes in KABD, HADD, and PD often exceeded SEM for all changes in knee flexion angles.

SIGNIFICANCE

Knee, hip, and pelvic frontal plane motions are influenced by knee flexion angles during 2D analysis of a SLS task. Our results highlight the importance of standardizing SLS depth during research and clinical practice to ensure appropriate comparisons across measurements.

Assessment of Dynamic Knee Valgus between Lateral Step-Down Test and Running in Female Runners with and without Patellofemoral Pain Using Two-Dimensional Video Analysis

Dynamic knee valgus (DKV) is a frontal plane knee kinematic alteration that has been associated with patellofemoral pain (PFP) in female runners. DKV is commonly assessed in clinical practice by measuring frontal plane knee projection angle (FPPA) during squat tests. However, it remains unclear whether the DKV observed in these tests is similar to or correlates with that observed during running in female runners. The aims of this cross-sectional study were to correlate and compare DKV, by measuring FPPA values, in a lateral step-down (LSD) squat test and running in female runners with and without PFP. A two-dimensional (2D) video analysis of the LSD test and running was carried out for 21 asymptomatic female runners and 17 PFP female runners in order to determine FPPA values. A Pearson correlation test and a factorial ANOVA with Bonferroni post hoc correction were used for statistical analysis. The FPPAs recorded in the LSD test were significantly higher than those recorded during running in the asymptomatic (16.32° ± 5.38 vs. 4.02° ± 3.26, p < 0.01) and PFP groups (17.54° ± 7.25 vs. 4.64° ± 3.62, p < 0.01). No significant differences were found in FPPA values between asymptomatic and PFP runners during the LSD test (16.32° ± 5.38 vs. 17.54° ± 7.25, p = 0.55) and running (4.02° ± 3.26 vs. 4.64° ± 3.62, p = 0.58). There was a small (r < 0.3) and non-significant (p > 0.05) correlation in FPPAs between the LSD test and running in both groups. According to our results, DKV was not similar during the LSD test and running, and there was no significant correlation in FPPA values between the LSD test and running in both groups. Therefore, clinicians and therapists should be aware of these findings when using the LSD test in clinical practice to evaluate DKV in female runners with or without PFP.

Association between Selected Screening Tests and Knee Alignment in Single-Leg Tasks among Young Football Players

This study aimed to examine the relationship between knee valgus in the frontal plane projection angle (FPPA) during single-leg squat (SLS), single-leg landing (SLL), and other selected clinical tests in young athletes. Forty-three young healthy elite football players (age: 13.2 (1.7) years) that were regularly training in a local sports club participated in the study. The FPPA was assessed using 2D video analysis. The screening tests included the passive single-leg raise (PSLR), hip external and internal rotation (hip ER and IR), sit and reach test, weight-bearing lunge test (WBLT), modified star excursion balance test (mSEBT), countermovement jump (CMJ), single-leg hop for distance (SLHD), and age peak height velocity (APHV). There was a significant positive relationship between the knee valgus angles in the SLS test and the sit and reach test (r = 0.34) and a negative relationship with the hip ER ROM (r = −0.34) (p < 0.05). The knee valgus angles in the SLL were negatively associated with the hip IR (r = −0.32) and ER ROM (r = −0.34) and positive associated with the WBLT (r = 0.35) and sit and reach test (r = 0.33) (p < 0.05). Linear regression analysis showed that the results of the hip ER ROM and sit and reach tests were independent predictors of the FPPA in the SLS test (r2 = 0.11, p = 0.03 and r2 = 0.12, p = 0.02, respectively). The conducted study showed that individuals with more hip range of motion, more spine flexion extensibility, and less ankle dorsiflexion ROM may be more likely to experience high degrees of knee valgus in FPPA.

Does weight loss affect the center of pressure of children with obesity: a follow-up study

Background

Children with obesity were found to show the greater postural instability compared to the normal-weighted children. However, it’s still unclear if their altered postural control ability would recover towards normal pattern after weight loss. The purpose of this study was to investigate the effect of weight loss on the center of pressure (COP) for obese children.

Method

Totally 147 children were conducted a follow-up study in three years. A total number of 22 participants aged 7–13 years were recruited for their remission of obesity problem after 36 months. Their dynamic plantar pressure data were collected by Footscan pressure plate. The normalized time of four sub-phases, displacements and velocities of COP in anterior–posterior (AP) and medial–lateral (ML) directions were calculated to perform the Kolmogorov–Smirnov test and paired sample t test for statistical analyses.

Results

After weight loss, children’s normalized time of forefoot contact phase (FFCP) increased significantly, and their duration of flat foot phase (FFP) decreased significantly. They also exhibited the more medial and posterior orientated COP path after weight loss. In ML-direction, the COP displacement during FFP and FFPOP increased, and the COP velocity during FFPOP increased. In AP-direction, COP velocity during FFP and FFPOP increased.

Conclusions

The findings indicated that weight loss would have effects on the COP characteristics and postural stability for obese children. COP trajectory can provide essential information for evaluating foot function. The findings may be useful for obese children, medical staff, and healthcare physician.

Graphical Abstract

Female athletes with ligament dominance exhibiting altered hip and ankle muscle co-contraction patterns compared to healthy individuals during single-leg landing

BACKGROUND

Anterior cruciate ligament (ACL) injury is one of the most serious knee injuries and occurs frequently during exercise. Altered hip and ankle muscle co-contraction patterns may contribute to dynamic knee valgus and ACL injury mechanisms. Lack of dynamic control of ground reaction force (GRF) is known to be contributing factor for ACL injury by placing excessive force on passive structures. Muscle co-contraction is a dynamic mechanism for GRF absorption. Therefore, any alterations in co-contraction might be a risk factor for ACL injury. Ligament dominance is a term to define individuals who rely more on ACL ligament for GRF control.

RESEARCH QUESTION

This study aimed to compare the muscle co-contraction patterns of distal and proximal knee muscles during single leg landing in female athletes with and without ligament dominance.

METHODS

This is a cross-sectional study. A total of 54 female athletes were assigned to the healthy (n = 27) and ligament dominance (n = 27) group based on their Tuck Jump test scores. The electromyography activity of the gluteus medius, adductor longus, tibialis anterior, peroneus longus, medial and lateral gastrocnemius was measured by an electromyography in drop down a 30-cm-high stair. A Multivariate Analysis of Variance (MANOVA) was used for statistical analysis (p ≤ 0.05).

RESULTS

The two groups demonstrated an overall significantly different muscle co-contraction patterns (P < 0.05). There was a decreased in co-contraction of proximal group and an increased co-contraction in the distal muscles in ligament dominant group.

SIGNIFICANCE

The findings have provided evidence to support the notion of neuromuscular imbalances in ligament dominance deficit. These findings can be useful for the coaches and experts to design preventive exercises and modify the current programs for the people affected by ligament dominance.

Validity and inter-rater reliability of ankle motion observed during a single leg squat

BACKGROUND

The single leg squat (SLS) test is a clinical functional test commonly used to evaluate clinically aberrant movement patterns of the knee. The SLS could be an interesting option to analyze ankle control in the frontal plane during dynamic load analysis. However, to date, there are no studies that have analyzed the associations between the increased subtalar joint pronation by navicular drop (ND) test and ankle control with single leg squat (SLS_ankle) using a three-point scale. The purpose of this study was to evaluate the reliability of a clinical observation method to assess and determine the relationship between navicular drop (ND) and ankle control on the SLS_ankle score.

METHODS

A total of fifty-five healthy, physically active (31 females and 24 males) volunteers participated in this study. The degree of subtalar pronation was assessed through the ND test, and the ankle control was defined as the ankle displacement in the frontal plane during the SLS.

RESULTS

We found good intra-rater and inter-rater agreement during SLS_ankle, with Kappa values from 0.731 to 0.750. The relationship between the SLS_ankle and ND was significant ; the Spearman's rank correlation coefficient was 0.504 (p < 0.05).

CONCLUSIONS

The SLS_ankle score supplied the clinical practice with a reliable and valid alternative for quantifying foot mobility in comparison to the ND test.

Immediate Effect of Ankle Mobilization on Range of Motion, Dynamic Knee Valgus, and Knee Pain in Women With Patellofemoral Pain and Ankle Dorsiflexion Restriction: A Randomized Controlled Trial With 48-Hour Follow-Up

CONTEXT

Restriction in ankle dorsiflexion range of motion (ROM) has been previously associated with excessive dynamic knee valgus. This, in turn, has been correlated with knee pain in women with patellofemoral pain.

OBJECTIVES

To investigate the immediate effect of 3 ankle mobilization techniques on dorsiflexion ROM, dynamic knee valgus, knee pain, and patient perceptions of improvement in women with patellofemoral pain and ankle dorsiflexion restriction.

DESIGN

Randomized controlled trial with 3 arms.

SETTING

Biomechanics laboratory.

PARTICIPANTS

A total of 117 women with patellofemoral pain who display ankle dorsiflexion restriction were divided into 3 groups: ankle mobilization with anterior tibia glide (n = 39), ankle mobilization with posterior tibia glide (n = 39), and ankle mobilization with anterior and posterior tibia glide (n = 39).

INTERVENTION(S)

The participants received a single session of ankle mobilization with movement technique.

MAIN OUTCOME MEASURES

Dorsiflexion ROM (weight-bearing lunge test), dynamic knee valgus (frontal plane projection angle), knee pain (numeric pain rating scale), and patient perceptions of improvement (global perceived effect scale). The outcome measures were collected at the baseline, immediate postintervention (immediate reassessment), and 48 hours postintervention (48 h reassessment).

RESULTS

There were no significant differences between the 3 treatment groups regarding dorsiflexion ROM and patient perceptions of improvement. Compared with mobilization with anterior and posterior tibia glide, mobilization with anterior tibia glide promoted greater increase in dynamic knee valgus (P = .02) and greater knee pain reduction (P = .02) at immediate reassessment. Also compared with mobilization with anterior and posterior tibia glide, mobilization with posterior tibia glide promoted greater knee pain reduction (P < .01) at immediate reassessment.

CONCLUSION

In our sample, the direction of the tibia glide in ankle mobilization accounted for significant changes only in dynamic knee valgus and knee pain in the immediate reassessment.

Relationships between Plantar Pressure Distribution and Rearfoot Alignment in the Taiwanese College Athletes with Plantar Fasciopathy during Static Standing and Walking

BACKGROUND

Plantar fasciopathy (PF) is usually related to changes in foot arch, foot shape and rearfoot posture. However, little research has been implemented by using large-scale datasets, and even less has been conducted centering on plantar pressure distributions (PPDs) of different genders of PF athletes. This study aimed to investigate the relationships among the arch index (AI), the PPDs and the rearfoot postural alignment in hundreds of college athletes with PF during static standing and walking.

METHODS

Cross-sectional study of 100 male and 102 female athletes with PF was undertaken. The PF athletes' pain assessment and self-reported health status were examined for evaluating their musculoskeletal painful areas.

RESULTS

The PF athletes' PPDs mainly concentrated on inner feet in static standing, and transferred to lateral forefeet during the midstance phase of walking. The males' PPDs from the static standing to the midstance phase of walking mainly transferred to anterolateral feet. The females' PPDs mainly transferred to posterolateral feet. The PF athletes' static rearfoot alignment matched the valgus posture pattern. The medial band of plantar fascia and calcaneus were the common musculoskeletal pain areas.

CONCLUSIONS

Characteristics of higher plantar loads beneath medial feet associated with rearfoot valgus in bipedal static stance could be the traceable features for PF-related foot diagrams. Higher plantar loads mainly exerted on the lateral forefoot during the midstance phase of walking, and specifically concentrated on outer feet during the transition from static to dynamic state. Pain profiles seem to echo PPDs, which could function as the traceable beginning for the possible link among pronated low-arched feet, PF, metatarsalgia, calcanitis and Achilles tendinitis.

Weak Hip Strength Increases Dynamic Knee Valgus in Single-Leg Tasks of Collegiate Female Athletes

Clinical Scenario: Dynamic knee valgus (DKV) is a mechanical alteration in the knee that leads to increased risk of injury. Weakness of hip musculature in hip abduction (HABD), extension (HEXT), and external rotation (HER) may contribute to increased DKV in single-leg landing tasks. Focused Clinical Question: Is decreased hip strength associated with an increase in DKV during a single-leg landing task in collegiate female athletes? Summary of Key Findings: Three studies were included: One randomized control trial (RCT), one cohort study, and one case-control. All three studies found that decreases in HABD and HER strength contributed to increased DKV during single-leg landing tasks. One study also found that the hip extensors contribute to controlling hip adduction, a common factor in many mechanisms of injuries. These three studies recommended strengthening HABD, HEXT, and HER to decrease DKV and reduce the risk of injury at the knee. Clinical Bottom Line: Weak HABD, HEXT, and HER contribute to increased DKV in college female athletes, but strengthening HABD, HEXT, and HER can lead to decreases in DKV and, overall, reduce the risk of injury at the knee. Strength of Recommendation: These articles were graded with a level of evidence of III or higher, giving a grade of B strength of recommendation that weak HABD, HEXT, and HER are associated with increased DKV in collegiate female athletes.

Are Core Stability Tests Related to Single Leg Squat Performance in Active Females?

Core stability (CS) deficits can have a significant impact on lower limb function. The aim of this study was to investigate the relationship between two dynamic core exercise assessments and dynamic knee valgus during single-leg squats. In total, 20 physically active female students participated in this study. The OCTOcore smartphone application assesses CS during two dynamic exercise tests, the partial range single-leg deadlift (SLD) test and the bird-dog (BD) test. A two-dimensional assessment of a single-leg squat test was used to quantify participants’ hip frontal angle (HFA_SLS) and knee frontal plane projection angle (FPPA_SLS). Ankle dorsiflexion was evaluated through the weight-bearing dorsiflexion test. The correlational analyses indicated that the HFA_SLS was significantly related to the partial range single-leg deadlift test (r = 0.314, p < 0.05) and ankle dorsiflexion (r = 0.322, p < 0.05). The results showed a significant difference (p < 0.05) in the CS test between cases categorised as dynamic knee valgus (>10°) and normal (≤10°). The CS deficit may influence the neuromuscular control of the lumbopelvic-hip complex during single-leg movements. The link between CS and kinematic factors related to knee injuries was only observed when CS was measured in the SLD test but not in the BD test.

Impact of Three Strengthening Exercises on Dynamic Knee Valgus and Balance with Poor Knee Control among Young Football Players: A Randomized Controlled Trial

The observed dynamic knee valgus and the limited dynamic balance described in the literature are modifiable risk factors for injuries in athletes. Therefore, identification and appropriate prevention are crucial in managing the development of young athletes. The aim of the study was to assess the effectiveness of three exercises strengthening the muscles: gluteal medius, popliteal and tibialis posterior to reduce dynamic knee valgus and improve the dynamic balance of the lower limbs in young football players with poor knee control. A total of 134 footballers were assessed for eligibility, and finally 45 participants (age 12–15) met the inclusion criteria. Participants were assessed with 2D video kinematic analysis during single-leg squats to assess the knee valgus angles and the dynamic balance (Y-Balance Test). No significant interactions between groups (Control and Exercise) and time (baseline and after 6 week) were noted for dynamic valgus for the left and right knee (p > 0.05). For the dynamic balance, there were statistically significant results, but not clinically relevant for anterior, posteromedial, and composite direction for the right lower limbs and for the anterior direction for left lower limbs in the exercise group. However, there were no significant differences (p > 0.05) in all of the YBT scores for both lower limbs between groups. This study demonstrated that there were no statistically significant differences in dynamic knee valgus angles and dynamic balance values after 6 weeks of exercise program in young footballers with poor knee control. Future randomized trials should focus on more comprehensive exercises, where possible using biofeedback methods to improve knee kinematics.

Relationship between passive ankle dorsiflexion range, dynamic ankle dorsiflexion range and lower limb and trunk kinematics during the single-leg squat

BACKGROUND

Limited passive ankle dorsiflexion range has been associated with increased knee valgus during functional tasks. Increased knee valgus is considered a contributing factor for musculoskeletal disorders in the lower limb. There is conflicting evidence supporting this association. The extent of passive ankle dorsiflexion range is associated with dynamic ankle dorsiflexion range and the way how these variables are related to lower limb or trunk kinematics is unclear.

RESEARCH QUESTION

What is the association between passive ankle dorsiflexion range or dynamic ankle dorsiflexion range with shank, thigh, pelvis or trunk movements during the single-leg squat?

METHODS

This is a cross-sectional study with a convenience sample. Thirty uninjured participants performed the single-leg squat with their dominant limb. Ankle, shank, thigh, pelvis and trunk 3D kinematics were recorded. Passive ankle dorsiflexion range was assessed through the weight-bearing lunge test and the dynamic ankle dorsiflexion range was defined as the ankle dorsiflexion range of motion in the sagittal plane during the single-leg squat.

RESULTS

Greater passive ankle dorsiflexion range was associated with smaller thigh internal rotation (r= -0.38). Greater dynamic ankle dorsiflexion range was associated with smaller trunk flexion (r = 0.59) and pelvis anteversion (r= -0.47). Passive ankle dorsiflexion range and dynamic ankle dorsiflexion range were not associated.

SIGNIFICANCE

Greater passive ankle dorsiflexion range seems to be associated with a better lower limb alignment during the single-leg squat, while dynamic ankle dorsiflexion range seems to reflect different lower limb and trunk kinematic strategies.

The Single Leg Squat Test: A "Top-Down" or "Bottom-Up" Functional Performance Test?

BACKGROUND

Medial knee deviation (MKD) during the single leg squat test (SLST) is a common clinical finding that is often attributed to impairments of proximal muscular structures. Investigations into the relationship between MKD and the foot and ankle complex have provided conflicting results, which may impact clinicians' interpretation of the SLST.

PURPOSE

The purpose of this study was to compare ankle dorsiflexion range of motion (ROM) and foot posture in subjects that perform the SLST with MKD (fail) versus without MKD (pass).

HYPOTHESIS

There will be a difference in ankle dorsiflexion ROM and/or foot posture between healthy individuals that pass and fail the SLST for MKD.

STUDY DESIGN

Cross-sectional study.

METHODS

Sixty-five healthy, active volunteers (sex = 50 female, 15 male; age = 25.2 +/- 5.6 years; height = 1.7 +/- .1 m; weight = 68.5 +/- 13.5 kg) who demonstrated static balance and hip abductor strength sufficient for performance of the SLST participated in the study. Subjects were divided into pass and fail groups based on visual observation of MKD during the SLST. Foot Posture Index (FPI-6) scores and measures of non-weight bearing and weight bearing active ankle dorsiflexion (ROM) were compared.

RESULTS

There were 33 individuals in the pass group and 32 in the fail group. The groups were similar on age (p = .899), sex (p = .341), BMI (p = .818), and Tegner Activity Scale score (p = .456). There were no statistically significant differences between the groups on the FPI-6 (pass group mean = 2.5 +/- 3.9; fail group mean = 2.3 +/- 3.5; p = .599), or any of the measures of dorsiflexion range of motion (non-weight bearing dorsiflexion with knee extended: pass group = 6.9o +/- 3.7o, fail group = 7.8o +/- 3.0o; non-weight bearing dorsiflexion with knee flexed: pass group = 13.5o +/- 5.6o, fail group = 13.9o +/- 5.3o; weight bearing dorsiflexion: pass group = 42.7o +/- 6.0o, 42.7o +/- 8.3o, p = .611).

CONCLUSIONS

Failure on the SLST is not related to differences in clinical measures of active dorsiflexion ROM or foot posture in young, healthy individuals. These findings suggest that clinicians may continue using the SLST to assess neuromuscular performance of the trunk, hip, and knee without ankle dorsiflexion ROM or foot posture contributing to results.

LEVEL OF EVIDENCE

Level 3.

Sex-dependent differences in single-leg squat kinematics and their relationship to squat depth in physically active individuals

The purpose of this study is to compare recreationally physically active females and males with regard to spine, pelvis and lower limb joints peak angles in each plane of motion during a single leg squat (SLS). The second aim is to investigate the relationship between kinematics and SLS depth in females and males. Fifty-eight healthy, young adults performed 5 repetitions of a single right leg squat to maximal depth while keeping their balance. Kinematic data were obtained using an optical motion capture system. At the hip, greater adduction and greater internal rotation were observed in females than in males. Females had more extended spines and less outward bended knees throughout the SLS than did men. In males, squat depth was significantly, positively correlated with the maximal angle of the ankle (r = 0.60, p < 0.001), the knee (r = 0.87, p < 0.001), the hip (r = 0.73, p < 0.001) and the pelvis (r = 0.40, p = 0.02) in the sagittal plane. A positive significant correlation was found between SLS depth and maximal angle of the knee (r = 0.88, p < 0.001) and the ankle (r = 0.53, p = 0.01) in the sagittal plane in females. Males and females used different motor strategies at all levels of the kinematic chain during SLS.

Dynamic Knee Valgus in Single-Leg Movement Tasks. Potentially Modifiable Factors and Exercise Training Options. A Literature Review

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.

A prospective study of the muscle strength and reaction time of the quadriceps, hamstring, and gastrocnemius muscles in patients with plantar fasciitis

Background

Muscle weakness is an important etiological factor in plantar fasciitis (PF), but available data on the role of the quadriceps, hamstring, and gastrocnemius (GCM) muscles are limited. The aim of this study was to compare the strength and reaction time of the quadriceps, hamstring, and GCM muscles and foot pressure between patients with PF and normal controls.

Methods

A total of 21 PF patients and 21 normal controls were enrolled. Muscle strength was measured by the peak torque per body weight (Nmkg^− 1 × 100). Muscle reaction time was evaluated by the acceleration time (AT, milliseconds). Foot pressure and posture were assessed by pedobarography [valgus/varus index (VV index), %].

Results

The strength of the quadriceps was significantly lower in the affected ankles of the PF group than in the control group (p = 0.005). The AT of the quadriceps and hamstring muscles was significantly increased in the affected ankles of the PF group than in the control group (quadriceps: p = 0.012, hamstring: p = 0.001), while the AT of the GCM muscle was significantly decreased (p = 0.009) and significantly correlated negatively with quadriceps muscle strength (r = −.598, p = 0.004) and AT (r = −.472, p = 0.031). Forefoot (p = 0.001) and hindfoot (p = 0.000) pressure were significantly greater, with the VV index showing hindfoot valgus, in the affected ankles in the PF group compared to the control group (p = 0.039).

Conclusions

This study demonstrated weakness and delayed reaction time of the quadriceps and hamstring muscles, with a rapid reaction time of the GCM muscle, in patients with PF.

Clinical relevance

Clinicians and therapists should assess the function of the quadriceps and hamstring muscles when planning the management of PF patients without muscle tightness.

Proximal and distal muscle thickness is different in women with patellofemoral pain but is not associated with knee frontal plane projection angle

OBJECTIVE

The aim of this study was to compare proximal and distal muscle thickness between patellofemoral pain (PFP) and asymptomatic women (CG) and to verify the possible association between morphology and lower limb alignment during single leg-squat.

METHODS

Thirty women (PFP, n = 15 and CG, n = 15) performed the following evaluations: (i) muscle thickness of external oblique (EO), gluteus medius (GMed), tensor fascia latae (TFL), peroneus (PER) and tibialis anterior (TA); (ii) knee frontal plane projection angle (FPPA) during single-leg squat.

RESULTS

Compared with the CG, PFP showed: (1) smaller GMed (-10.02%; p = 0.04; effect size = 0.82), greater TFL (+18.44%; p = 0.02; effect size = 0.92) and PER (+14.23%; p = 0.02; effect size = 0.87) muscle thickness and greater knee FPPA during single-leg squat (+31.8%; p = 0.04; effect size = 1.12). No differences were observed in EO (+7.17%; p = 0.37; effect size = 0.34) and TA (-1.35%; p = 0.81; effect size = 0.12) muscle thickness. Additionally, we failed to observe significant associations between muscle morphology and knee FPPA in both groups.

CONCLUSION

PFP patients showed alterations in proximal and distal muscle thickness, despite the lack of association with poor lower limb alignment. Prospective studies are necessary to determine if differences in muscle morphology are the cause or the consequence of PFP and to confirm the absence of relationship with lower limb alignment.

Associations of foot and ankle characteristics with knee symptoms and function in individuals with patellofemoral osteoarthritis

BACKGROUND

Foot and ankle characteristics are associated with patellofemoral pain (PFP) and may also relate to patellofemoral osteoarthritis (PFOA). A greater understanding of these characteristics and PFOA, could help to identify effective targeted treatments.

OBJECTIVES

To determine whether foot and ankle characteristics are associated with knee symptoms and function in individuals with PFOA.

METHODS

For this cross-sectional study we measured weightbearing ankle dorsiflexion range of motion, foot posture (via the Foot Posture Index [FPI]), and midfoot mobility (via the Foot Measurement Platform), and obtained patient-reported outcomes for knee symptoms and function (100 mm visual analogue scales, Anterior Knee Pain Scale [AKPS], Knee injury and Osteoarthritis Outcome Score, repeated single step-ups and double-leg sit-to-stand to knee pain onset). Pearson's r with significance set at p < 0.05 was used to determine the association between foot and ankle charateristics, with knee symptoms and function, adjusting for age.

RESULTS

188 participants (126 [67%] women, mean [SD] age of 59.9 [7.1] years, BMI 29.3 [5.6] kg/m2) with symptomatic PFOA were included in this study. Lower weightbearing ankle dorsiflexion range of motion had a small significant association with higher average knee pain (partial r = - 0.272, p < 0.001) and maximum knee pain during stair ambulation (partial r = - 0.164, p = 0.028), and lower scores on the AKPS (indicative of greater disability; partial r = 0.151, p = 0.042). Higher FPI scores (indicating a more pronated foot posture) and greater midfoot mobility (foot mobility magnitude) were significantly associated with fewer repeated single step-ups (partial r = - 0.181, p = 0.023 and partial r = - 0.197, p = 0.009, respectively) and double-leg sit-to-stands (partial r = - 0.202, p = 0.022 and partial r = - 0.169, p = 0.045, respectively) to knee pain onset, although the magnitude of these relationships was small. The amount of variance in knee pain and disability explained by the foot and ankle characteristics was small (R2-squared 2 to 8%).

CONCLUSIONS

Lower weightbearing ankle dorsiflexion range of motion, a more pronated foot posture, and greater midfoot mobility demonstrated small associations with worse knee pain and greater disability in individuals with PFOA. Given the small magnitude of these relationships, it is unlikely that interventions aimed solely at addressing foot and ankle mobility will have substantial effects on knee symptoms and function in this population.

TRIAL REGISTRATION

The RCT was prospectively registered on 15 March 2017 with the Australia and New Zealand Clinical Trials Registry ( ANZCTRN12617000385347 ).

Changes in Knee and Trunk Alignment in People With Hip Pain and Healthy Controls When Using a Decline Board During Single-Leg Squat

Context: Hip pain is associated with reduced hip muscle strength, range of movement (ROM), and decreased postural stability. Single-leg squat is a reliable and valid method to measure dynamic balance. Objective: To evaluate the influence of physical characteristics and use of a decline board on squat performance in a hip pain population. Design: Cross-sectional study setting. Clinical Patients: In total, 33 individuals scheduled for arthroscopic hip surgery were matched with 33 healthy controls. Interventions: Hip and ankle ROM, hip strength, and trunk endurance were assessed, along with knee and trunk kinematics during squat on flat and 25° decline surfaces. Main Outcome Measures: Between-group and surface differences in alignment, between-group strength and ROM, and associations between alignment and physical characteristics were assessed and determined using mixed model analysis of variance and Pearson R. Results: The hip pain group had significantly less strength and ROM for all directions except abduction strength and ankle dorsiflexion (P > .02). No differences existed between the 2 groups for trunk (P < .70) or knee displacement (P < .46) during squat on either surface. When the 2 groups were combined (n = 66), decline squat significantly reduced knee medial displacement in both limbs by approximately 1 cm (P < .01). Decline squat reduced trunk lateral movement on 1 side only (P = .03). Reduced knee displacement during decline squat showed fair association with less hip-extension strength (r = −.29), hip-flexion strength (r = −.25), and less dorsiflexion (r = −.24). Strength and range were not associated with trunk displacement. Conclusions: Decline squat reduced medial knee and lateral trunk displacement regardless of hip pain. Reductions may be greater in those with lesser hip muscle strength and dorsiflexion. Use of a decline board during squat for improving knee and trunk alignment should be considered as a goal of exercise intervention.

Core muscles thickness is not associated with knee frontal plane projection angle during single-leg squat in healthy people

BACKGROUND

Core muscles play an important role in lower limb stability and alignment, with their weakness being associated with poor alignment and, consequently, with injuries. Despite muscle structure being critical to muscle strength production, we did not find studies associating the morphology of the core muscles and lower limb alignment during functional tasks.

RESEARCH QUESTION

Is there association between thickness of core muscles (external oblique - EO, internal oblique - IO, transversus abdominis - TrA and gluteus medius - GMed) and lower limb alignment during the single-leg squat in healthy subjects?

METHODS

Forty-six healthy participants (27 male and 19 female) performed the following evaluations: (i) measurements of muscle thickness of the EO, IO, TrA and GMed using ultrasound and (ii) measurements of lower limb alignment using the knee frontal plane projection angle (FPPA) during the single-leg squat. A Spearman rank correlation coefficient (r_s) was performed between the thickness of selected core muscles (OE, OI, TrA and GMed) and the knee FPPA. In addition, a partial correlation (r) was performed, using sex, physical activity level and body mass index as control variables.

RESULTS

We did not observe significant correlations between the knee FPPA and the thickness of the EO (r_s = 0.194; p = 0.197), IO (r_s = 0.182; p = 0.225), TrA (r_s = 0.073; p = 0.627) and GMed (r_s = -0.092; p = 0.542). When controlling for sex, physical activity level and body mass index, similar results were observed [EO (r = 0.157; p = 0.316), IO (r = 0.261; p = 0.092), TrA (r = 0.030; p = 0.850) and GMed (r = -0.144; p = 0.356)] SIGNIFICANCE: Our results demonstrated that core muscles' thickness is not associated with lower limb alignment during the single-leg squat in healthy people.

Do hip strength, flexibility and running biomechanics predict dynamic valgus in female recreational runners?

BACKGOUND

Dynamic valgus has been the focus of many studies to identify its association to an increased risk of running-related injuries. However, it is not known which physical and biomechanical variables are associated with this movement dysfunction.

RESEARCH QUESTION

This study aimed to test the correlation between strength, flexibility and biomechanical variables and dynamic valgus in female runners.

METHODS

Twenty-nine healthy females ran on a treadmill at 2.92 m/s and performed strength, range of motion and endurance tests. Pelvic, hip and ankle kinematics were measured with a 3D motion analysis system. Six multiple linear regression models were used to identify the ability of physical and biomechanical variables to predict excursion and peak of contralateral pelvic drop, hip adduction and internal rotation.

RESULTS

Contralateral pelvic drop and hip adduction were positively correlated to ankle eversion and step cadence. Hip internal rotation had a negative correlation with ankle eversion. Despite significance, predictor variables explained less than 30% of dynamic valgus variance during running. No interest variable had significant correlation with the hip strength and hip and ankle passive range of motion.

SIGNIFICANCE

The results showed that distal joint kinematics and spatiotemporal variables should be considered during biomechanical running analysis to identify their possible relationship with joint overload caused by dynamic valgus. Caution should be taken when linking hip disorders during running to posterolateral hip strength and stiffness, core endurance, and ankle dorsiflexion range of motion since no correlation occurred amongstthese variables in this sample of female runners.

THE ROLE of a BIKE FIT in CYCLISTS with HIP PAIN. A CLINICAL COMMENTARY

Hip pathology is common amongst athletes and the general population. The mechanics of cycling have the potential to exacerbate symptomatic hip pathology and progress articular pathology in patients with morphologic risk factors such as femoroacetabular impingement. A professional fit of the bicycle to the individual which aims to optimize hip joint function can allow patients with hip pathology to exercise in comfort when alternative high impact exercise such as running may not be possible. Conversely improper fit of the bicycle can lead to hip symptoms in otherwise healthy individuals who present with risk factors for hip pain. Accordingly a bike fit can form part of the overall management strategy in a cyclist with hip symptoms. The purpose of this clinical commentary is to discuss hip pathomechanics with respect to cycling, bicycle fitting methodology and the options available to a physical therapist to optimize hip mechanics during the pedaling action.

Effects of ankle dorsiflexion limitation on lower limb kinematic patterns during a forward step-down test: A reliability and comparative study

BACKGROUND

Altered lower limb movement patterns (LLMP) during the forward step down (FSD) test have been studied in people suffering from knee instability. However, ankle dorsiflexion range of motion (ADROM) seems to be related to LLMP but no causal inference has been defined between those variables.

OBJECTIVE

Our goals were to evaluate (1) psychometric quality of the FSD test in healthy people and (2) the influence of experimental restricted ADROM on LLMP.

METHODS

Kinematics were measured by a motion capture system. Angular displacement and speed were calculated as well as center of mass (COM) and knee linear displacement. Forty-two healthy participants; firstly, performed the test three times to assess reliability, and secondly the same test in an experimental condition limiting the ADROM.

RESULTS

Reliability was excellent for all parameters (ICC: 0.75-0.99, SEM%: 2.0-34.0%). ADROM limitation significantly decreased Knee flexion range of motion (ROM) (-3.8∘), increased Hip flexion ROM (6∘), Hip adduction ROM (6.1∘), Pelvis drop ROM (3.5∘), Pelvic rotation ROM (3.1∘). No significant effect was found for Hip rotation ROM.

CONCLUSIONS

LLMP was affected by this experimental ADROM limitation in healthy people. As this limitation is often encountered in post-traumatic ankle sprain patients, clinicians should consider this point during FSD assessment test.

Is there a correlation in frontal plane knee kinematics between running and performing a single leg squat in runners with patellofemoral pain syndrome and asymptomatic runners?

BACKGROUND

Knee kinematics when running, specifically knee valgus, have been linked to patellofemoral pain syndrome. Assessing running biomechanics requires skill, equipment and time. Clinically, the single leg squat is used to make inferences about knee kinematics during running. No evidence supports this practice.

METHODS

Sixteen asymptomatic runners and sixteen runners with patellofemoral pain syndrome were recruited. Asymptomatic runners were sub-divided by dominant and non-dominant leg and runners with patellofemoral pain syndrome by painful and non-painful leg. This gave four groups. Participants were videoed performing single leg squats and running on a treadmill. Frontal plane knee kinematics were calculated using the frontal plane projection angle. Correlation in frontal plane projection angle between running and single leg squat were calculated using Pearson's correlation coefficient. Differences in frontal plane projection angle between groups for running and single leg squat were calculated using multiple independent t-tests with Bonferroni correction.

FINDINGS

Correlation in frontal plane projection angle between running and the single leg squat was not statistically significant for the painful leg group (p = 0.19) but was for the remaining groups (p < 0.05). There was no statistically significant difference in frontal plane projection angle between the four groups when running. Single leg squat frontal plane projection angle was significantly larger for the painful leg group (10.3°) than the dominant leg (-0.2° (p = 0.003)) and non-dominant leg (-0.4° (p = 0.004)) in the asymptomatic runners group.

INTERPRETATION

The single leg squat cannot be used to make inferences about frontal plane knee kinematics in running gait in patellofemoral pain syndrome sufferers.

Foot and ankle characteristics and dynamic knee valgus in individuals with patellofemoral osteoarthritis

Study design

Controlled laboratory study; cross-sectional design.

Background

Foot and ankle characteristics and dynamic knee valgus differ in people with and without patellofemoral (PF) pain. However, it is unknown if these characteristics are evident in people with PF osteoarthritis (OA), compared to pain-free older adults.

Objectives

To compare foot and ankle mobility, foot posture and dynamic knee valgus, measured as the frontal plane projection angle (FPPA) during single-leg squatting, between individuals with and without PFOA.

Methods

Fifty-one participants with PFOA (66% women, mean ± SD age 57 ± 10 years, body mass index (BMI) 27 ± 6 kg/m²), and 23 controls (56% women, age 56 ± 9 years, BMI 24 ± 4 kg/m²) had ankle dorsiflexion measured using the knee-to-wall test, foot mobility calculated as the difference in midfoot height or width between non-weightbearing and weightbearing, and static foot posture characterized utilizing the Foot Posture Index. Peak FPPA was determined from video recordings while participants performed 5 single-leg squats. Linear regressions examined between-groups relationships for foot and ankle characteristics and the FPPA.

Results

The PFOA group had less ankle dorsiflexion (odds ratio 6.7, 95% confidence interval 2.46-18.2), greater midfoot height mobility (5.2, 1.78-15.14) and width mobility (4.3, 1.33-14.39), and greater foot mobility magnitude (8.4, 2.32-30.69) than controls. There was no difference in FPPA (knee valgus angle) between groups (15, 0.63-377.99).

Conclusion

Foot and ankle characteristics were different in individuals with PFOA compared to control participants, however there was no difference in dynamic knee valgus during single leg squat. Clinical interventions to address greater foot mobility may be relevant for PFOA.

Athletes Rated as Poor Single-Leg Squat Performers Display Measurable Differences in Single-Leg Squat Biomechanics Compared With Good Performers

Context: It is important to validate single-leg squat visual rating criteria used in clinical practice and research. Foot orthoses may improve single-leg squat performance in those who demonstrate biomechanics associated with increased risk of lower limb injury. Objective: Validate visual rating criteria proposed by Crossley et al, by determining whether athletes rated as poor single-leg squat performers display different single-leg squat biomechanics than good performers; and evaluate immediate effects of foot orthoses on single-leg squat biomechanics in poor performers. Design: Comparative cross-sectional study. Setting: University laboratory. Participants: 79 asymptomatic athletes underwent video classification of single-leg squat performance based on established visual rating criteria (overall impression, trunk posture, pelvis “in space,” hip movement, and knee movement), and were rated as good (n = 23), fair (n = 41), or poor (n = 15) performers. Intervention: A subset of good (n = 16) and poor (n = 12) performers underwent biomechanical assessment, completing 5 continuous single-leg squats on their dominant limb while 3-dimensional motion analysis and ground reaction force data were recorded. Poor performers repeated the task standing on prefabricated foot orthoses. Main Outcome Measures: Peak external knee adduction moment (KAM) and peak angles for the trunk, hip, knee, and ankle. Results: Compared with good performers, poor performers had a significantly lower peak KAM (mean difference = 0.11 Nm/kg, 95% confidence interval = 0.02 to 0.2 Nm/kg), higher peak hip adduction angle (−4.3°, −7.6° to −0.9°), and higher peak trunk axial rotation toward their stance limb (3.8°, 0.4° to 7.2°). Foot orthoses significantly increased the peak KAM in poor performers (−0.06 Nm/kg, −0.1 to −0.01 Nm/kg), with values approximating those observed in good performers. Conclusions: Findings validate Crossley et al’s visual rating criteria for single-leg squat performance in asymptomatic athletes, and suggest that “off-the-shelf” foot orthoses may be a simple intervention for poor performers to normalize the magnitude of the external KAM during single-leg squat.

Single leg squat ratings by clinicians are reliable and predict excessive hip internal rotation moment

BACKGROUND

Single leg squats are commonly used subjective assessments of general biomechanical function, injury risk, as a predictor for recovery and as an outcome measure of rehabilitation. While 3D motion capture is a useful tool for elite sports performance and research it is impractical for routine clinical use.

RESEARCH QUESTION

This cross-sectional study aims to: assess reliability and validity of clinicians' subjective ratings of single leg squats compared to 3D motion capture, and to identify whether performance predicts joint moments.

METHODS

22 healthy military volunteers were simultaneously recorded on video and 3D motion capture performing single leg squats. Videos were reviewed twice by 5 physiotherapists rating performance on a 0-5 scale assessing squat depth, hip adduction, pelvic obliquity, pelvic tilt and trunk flexion summated into a composite score.

RESULTS

Hip adduction and trunk flexion exhibited moderate to substantial inter- and intra-rater reliability (range κ = 0.408-0.699) other individual criteria were mostly fair (κ ≤ 0.4). Composite scores for inter-rater reliability were ICC_(1,1) = 0.419 and ICC_(1,κ) = 0.783 and intra-rater reliability were ICC_(1,1) = 0.672 and κ(w) = 0.526. Validity against 3D kinematics was poor with only 6/75 individually rated criteria reaching κ > 0.40. Correlation was found between composite scores and hip internal rotation moment (r_s = 0.571, p = 0.009).

SIGNIFICANCE

Repeated use of single leg squats by a single practitioner is supported. Comparisons between clinicians are unreliable but improved by average measures from multiple raters. Heterogeneous reliability across scoring components suggests a qualitative description of the criteria scored is less ambiguous than using composite scores in a clinical setting. Composite scores may be more useful for analysis at a population level. Poor validity against kinematic data suggests clinicians use additional information upon which they find agreement such as estimating kinetics. Correlation between hip internal rotation moment and subjective ratings may be such an example of clinicians trying to identify excessive abnormal loading.

The association of ankle dorsiflexion and dynamic knee valgus: A systematic review and meta-analysis

OBJECTIVE

The objective of this systematic review was to evaluate the association between ankle dorsiflexion (ADF) and dynamic knee valgus (DKV).

METHODS

Electronic searches were conducted in MEDLINE, EMBASE, CINAHL and SPORTDiscus. A modified Downs and Black checklist was used for quality assessment and meta-analysis was performed to compare standardised mean differences (SMD) of ADF.

RESULTS

Seventeen studies met the inclusion criteria. Meta-analysis showed that reduced ADF is associated with participants presenting with DKV compared to controls (SMD -0.65, 95% CI -0.88 to -0.41). Subgroup analysis showed consistent results regarding different forms of ADF measurement; restriction in ADF measured in weight-bearing position (SMD -1.25, 95% CI -2.24 to -0.25), non-weight-bearing with knee flexed (SMD -0.56, 95% CI -0.97 to -0.16) or non-weight-bearing with knee extended (SMD -0.54, 95% CI -0.80 to -0.28) was significantly associated with DKV.

CONCLUSION

The meta-analysis results provide evidence that reduced ADF is correlated with DKV. The assessment of ADF in the clinical setting is important, as it may be related to harmful movement patterns of the lower limbs.