Hip external rotation stiffness and midfoot passive mechanical resistance are associated with lower limb movement in the frontal and transverse planes during gait

Non-linear interactions among hip and foot biomechanical factors predict foot pronation during walking in women

BACKGROUND

Interactions between hip and foot biomechanical factors may result in different magnitudes of foot pronation during walking.

OBJECTIVE

To investigate non-linear interactions between hip and foot biomechanical factors and their capability to predict foot pronation during walking and identify the profiles of biomechanical factors that predict greater and lower pronation.

METHODS

This is a cross-sectional study. Fifty-one women were classified into greater and lower foot pronation during walking. Biomechanical factors measured: (1) foot-ankle varus alignment, (2) hip passive stiffness, (3) isokinetic eccentric strength of hip external rotators, and (4) foot abduction angle. Classification and regression trees (CART) were used to investigate non-linear interactions that predict greater and lower foot pronation.

RESULTS

Four main profiles of biomechanical factors were identified as related to greater and lower foot pronation. Profiles for greater pronation were: (1) varus >25.83°; (2) interaction between varus ≤25.83° and hip stiffness ≤0.09 Nm/rad kg-1; (3) interaction between varus ≤25.83°, hip stiffness >0.09 Nm/rad kg-1, and foot abduction >19.58° The profile for lower pronation involved an interaction among varus ≤25.83°, hip stiffness >0.09 Nm/rad kg-1, and foot abduction ≤19.58° The model had 61% sensitivity and 96% specificity, with the total prediction of 78%. The area under the ROC curve was 0.79 (p = 0.001).

CONCLUSION

Foot-ankle varus, hip passive stiffness, and foot abduction predicted greater and lower foot pronation. Non-linear interactions between hip and foot factors influence the magnitude of foot pronation during walking. The observed profiles help identify which combinations of biomechanical factors should be assessed in individuals with increased or reduced pronation.

Reductions in rearfoot eversion posture due to proximal muscle strengthening are dependent on foot-ankle varus alignment

BACKGROUND

Strengthening the hip and trunk muscles may decrease foot pronation in upright standing due to expected increases in hip passive torque and lower-limb external rotation. However, considering the increased pronation caused by a more varus foot-ankle alignment, subjects with more varus may experience smaller or no postural changes after strengthening.

OBJECTIVE

To investigate the effects of hip and trunk muscle strengthening on lower-limb posture during upright standing and hip passive torque of women with more and less varus alignment.

METHODS

This nonrandomized controlled experimental study included 50 young, able-bodied women. The intervention group (n = 25) performed hip and trunk muscle strengthening exercises, and the control group (n = 25) maintained their usual activities. Each group was split into two subgroups: those with more and less varus alignment. Hip, shank, and rearfoot-ankle posture and hip passive external rotation torque were evaluated. Mixed analyses of variance and preplanned contrasts were used to assess prepost changes and between-group differences (α = 0.05).

RESULTS

The less-varus subgroup of the intervention group had a reduced rearfoot eversion posture (P = 0.02). No significant changes were observed in the less-varus subgroup of the control group (P = 0.31). There were no significant differences in posture between the control and intervention groups when varus was not considered (P ≥ 0.06). The intervention group had increased hip passive torque (P = 0.001) compared to the control group, independent of varus alignment.

CONCLUSION

Despite the increases in hip passive torque, the rearfoot eversion posture was reduced only in women with a less-varus alignment. Having more foot-ankle varus may prevent eversion reductions.

Clinical and biomechanical characteristics of responders and non-responders to insoles in individuals with excessive foot pronation during walking

This study aimed to identify the clinical and biomechanical factors of subjects with excessive foot pronation who are not responsive (i.e., "non-responders") to medially wedged insoles to increase knee adduction external moment. Ankle dorsiflexion range of motion, forefoot-shank alignment, passive hip stiffness, and midfoot passive resistance of 25 adults with excessive bilateral pronation were measured. Also, lower-limb angles and external moments were computed during walking with the participants using control (flat surface) and intervention insoles (arch support and 6° medial heel wedge). A comparison between "responders" (n = 34) and "non-responders" (n = 11) was conducted using discrete and continuous analyses. Compared with the responders, the non-responders had smaller forefoot varus (p = 0.014), larger midfoot passive internal torque peak (p = 0.005), and stiffness measured by the torsimeter (p = 0.022). During walking, non-responders had lower angle peaks for forefoot eversion (p = 0.001), external forefoot rotation (p = 0.037), rearfoot eversion (p = 0.022), knee adduction (p = 0.045), and external hip rotation (p = 0.022) and higher hip internal rotation angle peak (p = 0.026). Participants with small forefoot varus alignment, large midfoot passive internal torque, stiffness, small knee valgus, hip rotated internally, and foot-toed-in during walking did not modify the external knee adduction moment ("non-responders"). Clinicians are advised to interpret these findings with caution when considering the prescription of insoles. Further investigation is warranted to fully comprehend the response to insole interventions among individuals with specific pathologies, such as patellofemoral pain and knee osteoarthritis (OA).

Influence of reduced passive ankle dorsiflexion range of motion on lower limb kinetics and stiffness during gait

BACKGROUND

The ankle dorsiflexion range of motion (ADF-ROM) during single support phase allows elastic energy storage in the calcaneal tendon, contributing to advance the body forward. Reduced ADF-ROM may influence lower limb kinetics and stiffness.

RESEARCH QUESTION

What is the influence of reduced passive ADF-ROM on lower limb internal moments and stiffness during gait?

METHODS

Thirty-two participants, classified into two groups according to passive ADF-ROM (smaller than 10° and greater than 15°), were submitted to gait assessment at self-selected speed with a force platform and a three-dimensional motion analysis system. Statistical parametrical mapping (SPM) analyses were used to compare the lower limbs' internal moments between groups. Independent t-tests analyzed the differences between groups on lower limb stiffness during gait.

RESULTS

The lower ADF-ROM group had greater knee flexor moment (terminal stance and push-off), greater ankle abductor (i.e., shank internal rotator) moment in terminal stance and greater knee internal rotator moment in mid to terminal stance. The lower ADF-ROM group also had higher lower limb stiffness during gait.

SIGNIFICANCE

Individuals with reduced passive ADF-ROM had greater lower limb stiffness and adopted a gait pattern with increased knee and ankle moments, suggesting increased loading at these joints.

Quantitative evaluation of the vertical mobility of the first tarsometatarsal joint during stance phase of gait

We determined how the in vivo mobility of the first tarsometatarsal (TMT) joint can be quantified during gait. Twenty-five healthy participants (12 females) with no history of foot disorders were included. Non-invasive ultrasound (US) with a three-dimensional motion analysis (MA) system was used to evaluate the kinematic characteristics of first TMT joint during stance phase of gait. US probe was positioned longitudinally above the first TMT joint and adjusted to its proximal dorsal prominence. Gait analysis was conducted by the MA system starting with the activation of B-mode US video at 80 frames per second and 60-mm depth for simultaneous capture. During stance phase, the first metatarsal was translated dorsally with respect to the medial cuneiform, returning to a neutral level at toe-off in all subjects. During middle stance phase, the medial cuneiform was stable in males but displaced in the plantar direction in females and was the primary contributor to the differences in sagittal mobility observed between groups. Quantitatively measuring sagittal mobility of the first TMT joint could be useful for the early detection of foot abnormalities. The dynamic characteristics of the medial cuneiform during gait in healthy females may be associated with a high prevalence of hallux valgus.

Hip passive stiffness is associated with hip kinematics during single-leg squat

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 kg, 1.67 ± 8.9 m) 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 may demonstrate increased hip IR movement during SLS.

Is there a dose-response of medial wedge insoles on lower limb biomechanics in people with pronated feet during walking and running?

BACKGROUND

Although the effects of medial wedge insoles on lower limb biomechanics have been investigated, information about the effects of different magnitudes of medial posting is still lacking.

RESEARCH QUESTION

What are the dose-response effects of medial wedge insoles with postings varying between 0 °, 3 °, 6 °, and 9 ° of inclination on the lower limb biomechanics during walking and running in individuals with pronated feet?

METHODS

Sixteen participants with an FPI ≥ 6 were recruited. Four arch-supported insole conditions with varying degrees of medial heel wedge were tested (0°, 3°, 6°, and 9°). A 3D motion analysis system with force plates was used to obtain the kinetics and kinematics of walking and running at self-selected speeds. To compare the ankle, knee, and hip angles and moments among conditions, a time series analysis was performed using Statistical Parametric Mapping (SPM).

RESULTS

A reduction in ankle eversion angle was observed during walking for all insoles. For running, the 6° and 9° insoles decreased the ankle eversion angle during early stance and increased this angle during the propulsive phase. A decrease in ankle eversion moment was observed in walking and running for 6° and 9° insoles. An increase in knee adduction moment occurred in walking and running for all insoles. For hip, the 6° and 9° insoles showed, during walking, a decrease in hip adduction angle and an increase in hip adduction and external rotation moments. For most variables, statistical differences were found for a greater period across the stance phase as the medial wedge increased, except for ankle eversion moment and hip external rotation moment during walking.

SIGNIFICANCE

The biomechanical effects over the time series for many of the parameters increased with the addition of insole inclination, showing a dose-response effect of medial wedge insoles on the lower limb biomechanics during walking and running in adults with excessive foot pronation.

Midfoot passive stiffness affects foot and ankle kinematics and kinetics during the propulsive phase of walking

The midfoot joint complex (MFJC) is related to the mechanics and efficiency of the walking propulsive phase and low midfoot passive stiffness may require compensatory foot and ankle joint moments to avoid excessive pronation and inefficient propulsion. This study aimed to investigate the kinematics and kinetics of the MFJC and ankle during the propulsive phase of walking in subjects with larger and smaller midfoot passive stiffness. MFJC passive stiffness of 20 healthy adult participants, and the kinematics and kinetics of the MFJC (forefoot-rearfoot) and ankle (rearfoot-shank) during the stance phase of walking were measured. The participants were divided equally into two groups according to the MFJC passive stiffness. Ranges of motion (ROM) and mean joint moments were computed for the late stance. Independent t-tests (α = 0.05) revealed that subjects with lower midfoot passive stiffness showed an increased MFJC sagittal ROM (flattened longitudinal arch) (p = 0.002), increased ankle frontal ROM (more everted positions) (p = 0.002), increased MFJC frontal ROM (more inverted positions) (p = 0.019), as well as a tendency for larger ankle sagittal ROM (p = 0.056). They also showed increased MFJC (p = 0.021) and ankle (p = 0.018) moments in the sagittal plane, increased MFJC moment in the frontal plane (p = 0.047) and a tendency for a predominant ankle moment in the frontal (p = 0.058). Foot and ankle joint moments are possible strategies to reduce pronation and improve propulsion, but not sufficient to prevent the altered kinematics related to low midfoot stiffness. Therefore, midfoot passive stiffness is critical for foot and ankle kinematics and kinetics during walking propulsive phase and is a potential target of interventions.

Hip passive stiffness is associated with midfoot passive stiffness

BACKGROUND

Hip motion in the transverse plane is coupled with foot motion in the frontal plane during closed kinematic activities, such as gait. Considering that movement patterns and bone alignment might influence passive mechanical properties of joints in the long term, it is possible that hip passive stiffness and foot complex stiffness and alignment are related to each other.

OBJECTIVES

To investigate whether hip passive stiffness, midfoot passive stiffness and shank-forefoot alignment are related to each other.

METHOD

Thirty healthy adult individuals with a mean age of 25.4 years participated (18 women and 12 men). The Foot Torsimeter was used to measure midfoot stiffness, and hip stiffness and foot alignment were measured using clinical measures. Pearson and Spearman correlation coefficients were calculated to test the associations between each pair of variables, with α = 0.05.

RESULTS

Hip stiffness was positively correlated with midfoot absolute stiffness (r = 0.41, p = 0.02), indicating that increased hip stiffness is associated with increased midfoot stiffness. There were no associations between shank-forefoot alignment and the other variables.

CONCLUSIONS

In clinical settings, individuals with reduced hip passive stiffness may also have reduced midfoot passive stiffness, and vice versa. Shank-forefoot alignment is not linearly associated with hip or midfoot passive stiffness.

Interaction of foot and hip factors identifies Achilles tendinopathy occurrence in recreational runners

OBJECTIVES

To investigate the interaction of ankle-foot complex and hip joint factors with Achilles Tendinopathy (AT) occurrence in recreational runners.

DESIGN

Cross-sectional.

SETTING

Research Laboratory.

PARTICIPANTS

51 runners, 26 healthy and 25 with AT.

MAIN OUTCOMES MEASURES

Shank-forefoot alignment (SFA), weight bearing lunge test (WBLT), passive hip internal rotation (IR) range of motion (ROM), hip external rotators (ER) and ankle plantar flexors (PF) isometric strength. CART analyses were performed to assess interactions that could distinguish those with AT.

RESULTS

Passive hip IR ROM, ankle PF torque, SFA, and hip ER isometric torque were associated AT occurrence. The model correctly classified 92% of individuals without AT and 72% of those with AT. The area under the receiver operating characteristic curve was 0.88. Interaction factors revealed in nodes 3 and 10 were statistically significant. In node 3, runners with more than 29.33° of passive hip IR ROM had a 130% increased likelihood (PR = 2.30) of AT. Node 10 showed that individuals with higher PF torque, SFA varus, ER torque, but reduced passive hip IR ROM had an 87% increased likelihood (PR = 1.87) of AT.

CONCLUSION

Interactions between hip and foot factors could accurately classify recreational runners with and without AT.

The effects of small and large varus alignment of the foot-ankle complex on lower limb kinematics and kinetics during walking: A cross-sectional study

BACKGROUND

The alignment of the foot-ankle complex may influence the kinematics and kinetics of the entire lower limb during walking.

OBJECTIVES

This study investigated the effect of different magnitudes of varus alignment of the foot-ankle complex (small versus large) on the kinematics and kinetics of foot, ankle, knee, and hip in the frontal and transverse planes during walking.

DESIGN

Cross-sectional study.

METHOD

Foot-ankle complex alignment in the frontal plane was measured as the angle between the metatarsal heads and the inferior edge of the examination table, measured with the volunteer in prone maintaining the ankle at 0° in the sagittal plane. The participants (n = 28) were divided into two groups according to their alignment angles. The first group had values equal to or inferior to the 45 percentile, and the second group had values equal to or above the 55 percentile. The lower limb kinematics and kinetics were evaluated with the participant walking at self-select speed in an instrumented treadmill.

RESULTS

The group of large varus alignment showed significantly higher (p < 0.03) forefoot inversion angle at initial contact, amplitude of rearfoot-shank eversion, and peak of inversion ankle moment. There were no differences (p > 0.05) between the groups for knee and hip amplitudes and moments in the frontal and transverse planes. The durations of rearfoot-shank eversion, knee abduction, knee medial rotation, hip adduction, and hip medial rotation were not different between groups (p > 0.05).

CONCLUSION

Large varus alignment of the foot-ankle complex may increase the magnitude of foot pronation and ankle inversion moment during walking.