Frontal Plane Ankle Research Articles

Effects of shoe heel height on ankle dynamics in running

Shoes affect the evolved biomechanics of the foot, potentially affecting running kinematics and kinetics that can in turn influence injury and performance. An important feature of conventional running shoes is heel height, whose effects on foot and ankle biomechanics remain understudied. Here, we investigate the effects of 6–26 mm increases in heel height on ankle dynamics in 8 rearfoot strike runners who ran barefoot and in minimal shoes with added heels. We predicted higher heels would lead to greater frontal plane ankle torques due to the increased vertical moment arm of the mediolateral ground reaction force. Surprisingly, the torque increased in minimal shoes with no heel elevation, but then decreased with further increases in heel height due to changes in foot posture. We also found that increasing heel height caused a large increase in the ankle plantarflexion velocity at heel strike, which we explain using a passive collision model. Our results highlight how running in minimal shoes may be significantly different from barefoot running due to complex interactions between proprioception and biomechanics that also permit runners to compensate for modifications to shoe design, more in the frontal than sagittal planes.

Advanced footwear technology and its impacts on running mechanics, running economy and perception of male and female recreational runners

Studies on advanced footwear technology (AFT) often investigate potential performance benefits for constraint populations, and high running speeds. This research compared running biomechanics, running economy and perception between males and females, when wearing three different AFT conditions at recreational running speeds. An innovation shoe sample (IM) at confirmation stage in the product creation process was compared to two commercial running shoes (MM, MF). Gender and shoe variable means were compared for main and interaction effects (p < 0.05) by a mixed 2 × 3 repeated measures analysis of variance (RM ANOVA), and effect size estimation. A main effect was seen for shoe condition, both the IM and MF showed higher vertical loading rates than MM, and higher peak vertical force 1. IM had less frontal plane rearfoot motion than both the MM and MF. At the MTPJ, IM had lower maximum dorsiflexion angle, dorsiflexion velocity leading to lower negative power and negative work than both the MM and MF. IM and MF showed significantly lower oxygen consumption than the MM. Perception measurements showed IM and MF to be significantly softer, responsive and had better propulsion than the MM. A main effect was seen for gender, females exhibited higher vertical loading rates, reduced frontal plane ankle motion and lower MTPJ motion, and lower oxygen consumption compared to males. There was no gender effect for perception. Despite biomechanical differences, both IM and MF showed improved performance compared to the MM. Males and females exhibit different biomechanics when wearing AFT, however this did not lead to differences in subjective perception. It is concluded that the specific AFT applied for IM samples in this research functions for both groups largely similarly.

Task-specific differences in lower limb biomechanics during dynamic movements in individuals with chronic ankle instability compared with controls

BackgroundChronic ankle instability (CAI) has been associated with lower limb deficits that can lead to altered biomechanics during dynamic tasks. There have been contradictory findings in terms of ankle and hip joint biomechanics to date, influenced by the variety of movement tasks and varying definitions of the CAI condition. Research QuestionHow do biomechanical variables of the lower extremity differ during walking, running, and jump-landing in individuals with CAI compared with those without CAI? MethodsThirty-two individuals (17 CAI and 15 controls) participated in this retrospective case-control study. Sagittal and frontal plane ankle and hip joint angles and moments, and mediolateral foot balance (MLFB) were calculated during the tasks. Statistical parametric mapping (SPM) was used for the whole trajectory analysis to detect group differences. Discrete variables, including initial contact (IC) and peak angles and moments, were additionally compared. ResultsNo differences were found between groups during walking. During running, the CAI group exhibited a lower plantar flexor moment (p < 0.001) and more laterally deviated MLFB (p = 0.014) during mid-stance when compared to controls. Additionally, participants with CAI had a significantly greater peak plantar flexion angle in early stance (p = 0.022) and a reduced peak plantar flexor moment (p = 0.002). In the jump-landing, the CAI group demonstrated an increased hip extensor moment (p = 0.008), and a greater peak hip adduction angle (p = 0.039) shortly after ground contact compared to the control group. SignificanceDifferences in ankle and hip biomechanics were observed between groups during running and jump landing, but not during walking. These differences may be indicative of impairments in the sensorimotor system or of learnt strategies adopted to try to minimise instability and injury risk and can help to inform future intervention design.

Ankle mechanics during jump landings across different foot positions in professional ballet dancers

ABSTRACT This study aimed to investigate the effect foot position on ankle joint mechanics and vertical ground reaction forces (vGRF) across jump landings in professional ballet dancers. Twenty-seven professional ballet dancers (men: 14; women: 13) attended one data collection session, completing five maximal countermovement jumps in parallel, first, second, fourth, and fifth positions. Three-dimensional ankle mechanics, landing vGRF variables, and jump height were recorded via a seven-camera motion capture system and one force platform. A repeated measures multivariate analysis of variance was used to assess the main effects foot position across all target variables. A linear discriminate analysis was conducted to investigate target variables across foot positions. Frontal and transverse plane ankle mechanics had the largest impact when discriminating between foot positions. Ankle power in the transverse plane during jump landing in fourth was double that of all other positions. Our findings suggest that ankle range of motion should be restored before returning to jumps in fourth and fifth positions following distal lower extremity injury. The multiplanar energy transfer observed indicates a need for specific exercises to develop multiplanar force and rate of force development of local structures around the ankle.

Varus knee osteoarthritis with ankle osteoarthritis demonstrates greater hindfoot inversion and larger ankle inversion loading during gait following total knee arthroplasty compared to varus knee osteoarthritis alone.

Although patients with varus knee osteoarthritis (KOA) and concurrent ankle osteoarthritis (AOA) may experience increased ankle joint pain after total knee arthroplasty (TKA), the underlying mechanism remains unclear. This study aimed to investigate the effects of concurrent AOA on ankle and hindfoot alignment, frontal plane ankle and hindfoot biomechanics during gait following TKA and the clinical outcomes. Twenty-four patients with varus KOA who underwent TKA were included in this retrospective cohort study. Patients were categorized into two groups: with and without AOA. Radiographic evaluations of lower-limb, ankle and hindfoot alignment, and knee and ankle clinical outcomes were conducted preoperatively and 6 months postoperatively. In addition, gait analyses were performed to investigate knee, ankle and hindfoot kinematics and kinetics. Each data was compared between patients with and without AOA. Concomitant AOA was found in eight ankles. The AOA group exhibited greater postoperative hindfoot varus and increased postoperative ankle pain than the non-AOA group. Gait analysis showed no significant differences in knee varus alignment or tibial tilt after TKA between the groups. However, the AOA group demonstrated significantly greater hindfoot inversion and larger ankle inversion loading. One third of patients who underwent TKA had concurrent AOA associated with hindfoot varus. Despite achieving proper coronal knee alignment postoperatively, these patients experienced greater hindfoot and ankle joint inversion load during gait. Surgeons should consider the inability to evert the hindfoot and the possibility of increased ankle joint pain when planning and performing TKA. Level III.

Neuromuscular Electrical Stimulation of Peroneal Longus on Balance Control Ability in Young Adults with Chronic Ankle Instability: A Randomized Controlled Trial.

This study aimed to investigate the effects of six weeks of peroneal longus neuromuscular electrical stimulation (NMES) on the balance control ability in young adults with chronic ankle instability (CAI). This study is a double blind randomized controlled trial. Six weeks of NMES and placebo intervention were conducted in the NMES and control groups for 20 minutes, three times a week, respectively. Thirty-eight participants successfully completed the whole intervention and single-leg standing tests. The kinetics data of the center of pressure (COP) trajectory during static single-leg stance were measured using a Kistler force platform. Two-way repeated measures ANOVA was used to analyze the electrical stimulation effects. Significant interactions were detected in CAIT scores and all balance parameters including Displacement X (Dx), Displacement Y(Dy), 95% confidence ellipse area (95%AREA), root-mean-square (RMS) and COP mean displacement velocity (MV) (p < 0.05, 0.103 ≤ η2 ≤ 0.201). Significant between-group differences were found in CAIT scores (p = 0.003, Cohen's d = 0.215), Dx (p = 0.045, Cohen's d = 0.107), RMS-ml (p = 0.019, Cohen's d = 0.143) and 95%AREA (p = 0.031, Cohen's d = 0.123) after the six weeks interventions. Six weeks of NMES on the peroneus longus can improve static balance control ability in young adults with CAI, especially the stability of ankle frontal plane.

The association of range of motion, lower limb strength, and load during jump landings in professional ballet dancers

This study aimed to investigate the associations between peak plantarflexion ankle joint moments and vertical ground reaction forces (vGRF) during jump landings, and static ankle dorsiflexion range of motion (ROM), three-dimensional ankle excursions, and lower extremity strength in professional ballet dancers. Twenty-seven professional ballet dancers volunteered to participate (men = 14, women = 13). Participants attended one data collection session to measure dorsiflexion ROM and isometric lower extremity strength. Two further sessions were used to establish ankle mechanics and vGRFs during countermovement jump landings in seven foot positions, via a seven-camera motion capture system and piezoelectric force platform. Two linear mixed-effects models were used to investigate associations between the target variables and strength, dorsiflexion ROM, and ankle excursions. Dancer identification, sex, and foot position were entered as random effects. Model fit, when considered independent of random effects, was generally poor with the predictor variables explaining little of the variance of peak plantarflexion ankle joint moments (R2 = 0.02) or vGRF (R2 = 0.01). Model fit improved when random effects were considered (R2 = 0.65 & 0.34). Frontal plane ankle excursion was the only predictor variable with a significant negative association with peak plantarflexion ankle joint moments (p = .016), although coefficient estimates were small. Strength, static ankle dorsiflexion ROM, and three-dimensional ankle excursions are poor predictors of load experienced at a joint and system level in professional ballet dancers. Differences between individuals, sex, and foot position may be better indicators of the load experienced during jump landings.

The influence of midsole thickness on running turns

Running race courses typically feature numerous turns, an element of a race typically neglected. If a thick midsole were to decrease frontal plane ankle stability, it could potentially lead to a misalignment of lower limb joints, thereby affecting turn running and overall race performance. Therefore, the purpose of this study was to determine the influence of midsole thickness on turn running performance and peak frontal plane ankle angle. Thirteen recreational athletes participated in this study, which examined the effects of two footwear conditions: one with a 35-mm thick midsole and the other with a 50-mm thick midsole. Participants performed ten running trials around each of three turns of radii 3, 6 and 9 m. No significant differences were found between footwear conditions with respect to time to completion (p = 0.028), centre of mass velocity (p = 0.179) or frontal plane ankle angle (p = 0.935) across any of the three turns. These findings would suggest footwear manufactures need not consider the impact of midsole thickness on turn running performance when designing advanced footwear technology (AFT) and consumers need not avoid a substantial stack height when purchasing running shoes.

Motion Analysis of a Frontal Plane Adaptable Prosthetic Foot.

ABSTRACT Introduction An objective of designing a prosthetic foot is to achieve the natural adaptability of the foot and ankle on various surfaces and different forms of gait. Frontal plane position of the foot relative to the shank changes with many functional aspects of gait, such as turning, stairs, and walking on uneven ground. Prosthetic foot designs have variable frontal plane adaptability. An investigation foot with a linkage with ±10° of frontal plane motion was developed to improve frontal plane response under various conditions. The purpose of this study was to compare the kinematics of locked and unlocked conditions of a frontal plane adaptable prosthetic foot and the person’s usual foot while walking forward on a level surface, on an unstable rock surface, and sidestep, using a crossover design. These different conditions result in changes in frontal plane motion in the anatomical foot and ankle, and the current study evaluates whether there are similar trends in prosthetic feet. Materials and Methods People were included if they had a unilateral below-knee amputation, intact residual limb skin, were over 16 years old, and were able to walk more than 400 m on level ground without using a walking aid and without an increase in pain. The control group was people without amputations who completed the procedures once. Participants with amputations completed forward walking on level ground, on an unstable rock surface, and sidestep with their usual foot. Then after 2 weeks of accommodation, participants repeated these tests with the investigational foot unlocked and locked. Motion analysis data were collected with a 12-camera optically based system. Primary outcomes were sagittal and frontal plane motions of the foot relative to the shank. In addition, step length, step width, and stride velocity were obtained from the kinematic measures. Paired t-tests were used for statistical inference for individual participant comparisons. Unpaired t-tests were used for comparisons between the controls and people with amputations. Results Twenty-one people with amputations and 10 controls completed the tests. Participants with amputation had 16 different usual feet. There was a wide variation in usual foot motion during forward walking, whereas investigational foot conditions showed less variability. During level walking, control subjects had more frontal plane motion than any of the foot conditions, and the unlocked had more frontal plane motion than the usual foot and locked condition. Walking across an unstable rock surface showed similar trends, with control participants having more sagittal and frontal plane ankle motion compared with any prosthetic foot condition. Also, the unlocked had statistically greater frontal plane motion than the usual foot or locked condition. Sidestep results were also consistent with other gait tests. The control participants’ sagittal plane ankle range of motion was significantly more than the prosthetic sagittal plane motion for all foot conditions, whether the prosthetic side was leading or trailing. There was significantly more frontal plane motion with the unlocked than the usual foot and locked condition when the prosthetic foot was trailing or leading. Discussion and Conclusions Wide variation in usual foot range of motions in the frontal and sagittal planes confirmed the need for additional controls when considering the effect of the linkage alone. The unlocked had increased frontal plane ranges of motion compared with the locked and the majority of usual foot for all gait conditions, including level walking. This finding demonstrated that people with amputations were functionally using the additional range of motion provided by the linkage. However, control subjects used more range of motion in both the sagittal and frontal planes for the unstable rock surface and sidestepping. Increased frontal plane range of motion did not translate into improved stride length and velocity, step width, or center of mass deviations. Clinical Relevance The person-specific functional activities should be considered when choosing a prosthetic foot. A prosthesis with frontal plane motion may be applicable for a person who moves in a sidestep pattern or on uneven ground.

External Ankle Support and Ankle Biomechanics in Chronic Ankle Instability: Systematic Review and Meta-Analysis.

To systematically review the literature to determine whether external ankle supports influence ankle biomechanics in participants with chronic ankle instability (CAI) during sport-related tasks. A literature search of MEDLINE, SPORTDiscus, and CINAHL databases was conducted in November 2021. Included studies were randomized crossover or parallel-group controlled trials in which researchers assessed ankle biomechanics during landing, running, or change of direction in participants with CAI using external ankle supports compared with no support. Two authors independently identified studies, extracted data, and assessed risk of bias (Cochrane risk-of-bias tool version 2) and quality of evidence (Grading of Recommendations Assessment, Development and Evaluation). Random-effects meta-analysis was used to compare between-groups mean differences with 95% CIs. Grading of Recommendations Assessment, Development and Evaluation recommendations were used to determine the certainty of findings. A total of 13 studies of low to moderate risk of bias were included. During landing, very low-grade evidence indicated external ankle supports reduce frontal-plane excursion (mean difference [95% CI] = -1.83° [-2.97°, -0.69°], P = .002), plantar-flexion angle at initial contact (-3.86° [-6.18°, -1.54°], P = .001), and sagittal-plane excursion (-3.45° [-5.00°, -1.90°], P < .001) but not inversion angle at initial contact (-1.00° [-3.59°, 1.59°], P = .45). During running, very low- to low-grade evidence indicated external ankle supports reduce sagittal-plane excursion (-5.21° [-8.59°, -1.83°], P = .003) but not inversion angle at initial contact (0.32° [-2.11°, 1.47°], P = .73), frontal-plane excursion (-1.31° [-3.24°, 0.63°], P = .19), or plantar-flexion angle at initial contact (-0.12° [-3.54°, 3.29°], P = .94). Studies investigating changes of direction were insufficient. Very low-grade evidence indicated external ankle supports reduce frontal-plane excursion but not inversion angle at initial contact in participants with CAI during landing. Limiting frontal-plane excursion may reduce ankle-sprain risk. Frontal-plane ankle kinematics were not influenced by external ankle supports during running. Sagittal-plane reductions were observed with external ankle supports during landing and running with low to very low certainty, but their influence on ankle-sprain risk is undetermined.

The Influence of Footwear Midsole Thickness on Running Economy and Frontal Plane Ankle Stability

Despite being an intricate part of advanced footwear technology, the impact of midsole thickness is not well understood. While some individuals have speculated an increased midsole thickness might bequeath an unfair performance advantage, others have suggested it may have a detrimental impact on frontal plane ankle stability. Therefore, the purpose of this study was to determine the influence of midsole thickness on running economy, and frontal plane ankle stability. Twenty one recreational runners (ten female, and eleven male) participated in this study, performing five-minute treadmill running trials in four footwear conditions. The footwear conditions were nearly identical except for their midsole thicknesses which ranged from 35- to 50-mm in increments of 5-mm. Midsole thickness was not found to influence the energetic cost of running however, it was found to decrease frontal plane ankle stability. Given these results World Athletic restrictions on midsole thickness may be unnecessary and worthy of reconsideration.

Concurrent validation of the Xsens IMU system of lower-body kinematics in jump-landing and change-of-direction tasks

Inertial measurement units (IMUs) allow for measurements of kinematic movements outside the laboratory, persevering the athlete-environment relationship. To use IMUs in a sport-specific setting, it is necessary to validate sport-specific movements. The aim of this study was to assess the concurrent validity of the Xsens IMU system by comparing it to the Vicon optoelectronic motion system for lower-limb joint angle measurements during jump-landing and change-of-direction tasks. Ten recreational athletes performed four tasks; single-leg hop and landing, running double-leg vertical jump landing, single-leg deceleration and push off, and sidestep cut, while kinematics were recorded by 17 IMUs (Xsens Technologies B.V.) and eight motion capture cameras (Vicon Motion Systems, Ltd). Validity of lower-body joint kinematics was assessed using measures of agreement (cross-correlation: XCORR) and error (root mean square deviation and amplitude difference). Excellent agreement was found in the sagittal plane for all joints and tasks (XCORR > 0.92). Highly variable agreement was found for knee and ankle in transverse and frontal plane. Relatively high error rates were found in all joints. In conclusion, this study shows that the Xsens IMU system provides highly comparable waveforms of sagittal lower-body joint kinematics in sport-specific movements. Caution is advised interpreting frontal and transverse plane kinematics as between-system agreement highly varied.

Video Analysis of 26 Cases of Second ACL Injury Events in Collegiate and Professional Athletes.

Significant effort has gone into the identification and quantification of the underlying mechanisms of primary ACL injury. Secondary ACL injury is observed in approximately 1/4 to 1/3 of athletes who return to sport following ACL reconstruction. However, little has been done to evaluate the mechanisms and playing circumstances surrounding these repeat injuries. The purpose of this study was to characterize the mechanisms of non-contact secondary ACL injuries using video analysis. It was hypothesized that in video recordings of secondary ACL injury, athletes would exhibit greater frontal plane hip and knee angles, but not greater hip and knee flexion, at 66 ms following initial contact (IC) as compared to at IC and 33ms following IC. Cross-Sectional Study. Twenty-six video recordings of competitive athletes experiencing secondary ACL ruptures via noncontact mechanisms were analyzed for lower extremity joint kinematics, playing situation, and player attention. Kinematics were assessed at IC as well as 33 ms (1 broadcast frame) and 66 ms (2 broadcast frames) following IC. Knee flexion and knee frontal plane angles were greater at 66 ms than IC (p ≤ 0.03). Hip, trunk, and ankle frontal plane angles were not greater at 66 ms than IC (p ≥ 0.22). Injuries were distributed between attacking play (n=14) and defending (n=8). Player attention was most commonly focused on the ball (n=12) or an opponent (n=7). A single-leg landing accounted for just over half of the injuries (54%), while a cutting motion accounted for the remainder of the injuries (46%). Secondary ACL injury was most likely to occur during landing or a sidestep cut with player attention external to their own body. Knee valgus collapse combined with limited hip motion was identified in the majority of secondary injuries. Level IIIb.

Foot and Shank Coordination During Walking in Copers Compared With Patients With Chronic Ankle Instability and Controls

Chronic ankle instability (CAI) alters sensorimotor function and joint coordination, but ankle coordination during walking in copers (patients with a history of ankle sprain without any residual symptoms of CAI) remains unknown. To identify foot and shank coordination patterns that discriminate among individuals with CAI, copers, and healthy controls and to investigate whether copers display a different strategy to overcome altered sensorimotor function after a lateral ankle sprain compared with individuals with CAI and healthy controls. Controlled laboratory study. A total of 51 participants (17 participants with CAI, 17 copers, 17 healthy controls) walked on an instrumented treadmill at a fixed speed of 1.20 m/s for a 10-second trial, from which 8 consecutive gait cycles were extracted for analysis. Heel strike and toe-off were identified for each stance phase, and each stance phase was normalized to 100 time frames. A curve analysis was performed to detect group mean differences in vector coding coupling angles and coordination variabilities for sagittal plane ankle motion/transverse plane tibial plane motion (SAK/TT) and frontal plane ankle motion/transverse plane tibial motion (FAK/TT) with 90% CIs. During the terminal stance, CAI and coper groups demonstrated an inversion-tibial external rotation coupling, while controls displayed a dorsiflexion-tibial internal rotation strategy. During midstance, there were no differences between the coper, CAI, or control groups. At 0% to 20% of stance, the CAI group showed the most variability, while copers showed the least. During midstance, both copers and controls displayed an increase in variability earlier than the CAI group. The CAI group displayed a peak in variability from 39% to 43% of stance, which was greater than copers. During the propulsive phase (from heel-off to toe-off), the CAI group showed greater SAK/TT variability than both copers and controls. Similar to SAK/TT variability, the CAI group showed an earlier peak in FAK/TT variability compared with controls. The CAI, coper, and control groups displayed different ankle joint coupling patterns and coordination variability during a walking gait cycle. Copers may have the ability to alter their coordination during walking, which may help us understand the underlying mechanism of CAI.

Relationship Between Age and Running Kinematics in Female Recreational Runners.

Sex-based analyses are important when studying running kinematics. Females experience a unique aging process and demonstrate differences in running biomechanics from males. The purpose was to determine the relationship between age and running kinematics in female runners. Forty-six female runners (18-65y) ran at self-selected jogging and maximal speed on a treadmill. Lower-extremity joint kinematics were calculated, and 2 principal component analyses (jogging speed and maximal speed) were performed from kinematic variables. Regression was used to examine the relationship between age and identified components, and between age and the variables with the highest loadings within these components. For jogging speed, there was a positive relationship between age and ankle varus at initial contact and a negative relationship between age and peak eversion, hip adduction, knee flexion, dorsiflexion, and hip adduction at initial contact (Ps < .05). For maximal speed, initial contact ankle frontal plane angle became more positive with age, and there was a negative relationship with age and peak eversion, dorsiflexion and knee flexion, and knee flexion and hip adduction at initial contact (Ps < .05). Primarily distal joint angles decreased with increasing age in female recreational runners at self-selected running speeds.

Frontal plane ankle stiffness increases with axial load independent of muscle activity

Ankle sprains are the most common musculoskeletal injury, typically resulting from excessive inversion of the ankle. One way to prevent excessive inversion and maintain ankle stability is to generate a stiffness that is sufficient to resist externally imposed rotations. Frontal-plane ankle stiffness increases as participants place more weight on their ankle, but whether this effect is due to muscle activation or axial loading of the ankle is unknown. Identifying whether and to what extent axial loading affects ankle stiffness is important in understanding what role the passive mechanics of the ankle joint play in maintaining its stability. The objective of this study was to determine the effect of passive axial load on frontal-plane ankle stiffness. We had subjects seated in a chair as an axial load was applied to the ankle ranging from 10% to 50% body weight. Small rotational perturbations were applied to the ankle in the frontal plane to estimate stiffness. We found a significant, linear, 3-fold increase in ankle stiffness with axial load from the range of 0% body weight to 50% body weight. This increase could not be due to muscle activity as we observed no significant axial-load-dependent change in any of the recorded muscle activations. These results demonstrate that axial loading is a significant contributor to maintaining frontal-plane ankle stability, and that disruptions to the mechanism mediating this sensitivity of stiffness to axial loading may result in pathological cases of ankle instability.

Biomechanical Risk Factors of Injury-Related Single-Leg Movements in Male Elite Youth Soccer Players

Altered movement patterns during single-leg movements in soccer increase the risk of lower-extremity non-contact injuries. The identification of biomechanical parameters associated with lower-extremity injuries can enrich knowledge of injury risks and facilitate injury prevention. Fifty-six elite youth soccer players performed a single-leg drop landing task and an unanticipated side-step cutting task. Three-dimensional ankle, knee and hip kinematic and kinetic data were obtained, and non-contact lower-extremity injuries were documented throughout the season. Risk profiling was assessed using a multivariate approach utilising a decision tree model (classification and regression tree method). The decision tree model indicated peak knee frontal plane angle, peak vertical ground reaction force, ankle frontal plane moment and knee transverse plane angle at initial contact (in this hierarchical order) for the single-leg landing task as important biomechanical parameters to discriminate between injured and non-injured players. Hip sagittal plane angle at initial contact, peak ankle transverse plane angle and hip sagittal plane moment (in this hierarchical order) were indicated as risk factors for the unanticipated cutting task. Ankle, knee and hip kinematics, as well as ankle and hip kinetics, during single-leg high-risk movements can provide a good indication of injury risk in elite youth soccer players.

Hindfoot Flexibility Influences the Biomechanical Effects of Laterally Wedged Insoles and Ankle-Foot Orthoses in Medial Knee Osteoarthritis

ObjectiveTo investigate the relationship of frontal plane ankle mobility with the effects of an ankle-foot orthosis (AFO) and a laterally wedged insole (LWI) on knee adduction moment (KAM) in the treatment of medial knee osteoarthritis. DesignRandomized, nonblinded crossover trial. SettingOutpatient clinic of university hospital. ParticipantsReferred sample of 20 patients (N=20) with medial knee osteoarthritis stage 1-3 (Kellgren and Lawrence), aged 56.4±6.5 years; 58 patients were assessed, 21 were included, and 1 was a dropout. There were 14 healthy reference participants without knee osteoarthritis (convenience sample) who were matched by age. InterventionsPatients received AFO and LWI for 6 weeks each with gait analysis after each 6-week intervention. Patients underwent additional barefoot gait analysis, walking on even ground and on a cross slope of 5° lateral elevation and standing on inclinations of 0°, 5°, 10°, and 20°. Main Outcome MeasuresSpearman correlation between the immediate change in first peak of KAM with each aid and the change in hindfoot varus on the cross slope relative to level ground. ResultsThe KAM reduction with AFO correlated significantly with hindfoot varus reaction to the cross slope during walking: the greater the hindfoot valgization on the cross slope, the greater the KAM reduction with AFO (Spearman ρ=0.53, P=.02).The KAM reduction with LWI correlated moderately negatively with the change in hindfoot varus: the greater the hindfoot valgization on the cross slope, the smaller the KAM reduction with LWI (r=−0.31 P=.18). ConclusionsLWI may be suitable for patients with limited to normal frontal plane ankle mobility. Patients with greater frontal plane ankle mobility benefit most from frontal plane ankle bridging with AFO. Studies with larger samples are necessary.

Is There a Relationship Between Foot Reaction Time and Ankle Frontal Plane Torque in Female Soccer Athletes: A Pilot Study

Is There a Relationship Between Foot Reaction Time and Ankle Frontal Plane Torque in Female Soccer Athletes: A Pilot Study

Running Biomechanics Of Youth With Autism Spectrum Disorder

PURPOSE: Research examining gait biomechanics of persons with autism spectrum disorder (ASD) has grown significantly in recent years and has demonstrated that persons with ASD walk at slower self-selected speeds and with shorter strides, wider step widths, and reduced lower extremity biomechanics compared to neurotypical controls. In contrast to walking, running has yet to be examined in persons with ASD. The purpose of this study was to examine lower extremity running biomechanics in adolescents (13-18 year-olds) with ASD and matched (age, sex, and body mass index) neurotypical controls. METHODS: Three-dimensional kinematics and ground reaction forces (GRF) were recorded while participants ran at two matched speeds: self-selected speed of adolescents with ASD and at a standardized 3.0 m/s. Sagittal and frontal plane ankle, knee, and hip biomechanics along with vertical ground reaction force (GRF) waveforms were normalized to the stance phase of running. Waveforms were compared using two-way ANOVAs group x speed) via statistical parametric mapping (alpha at 0.04). RESULTS: Adolescents with ASD ran with reduced GRFs (by 14.5%), plantarflexion moments (18.5%), hip abduction moments (44.4%), and knee abduction moments (69.4%), each surrounding their respective peaks (all p < 0.001). Running at 3.0 m/s increased sagittal plane hip and knee moments surrounding initial contact (both 10.4%; p < 0.004) and frontal plane knee angles during mid (2.9 deg; p = 0.003) and late stance (2.8 deg; p = 0.003) compared to self-selected speeds. CONCLUSIONS: This study illustrates that adolescents with ASD run with reduced contributions from the plantarflexors and hip abductor musculature, which contribute to vertical GRFs. Educators and therapists should consider examining running mechanics, in addition to walking, of adolescents with ASD to determine if muscular or neural deficiencies contribute to reduced hip and ankle involvement.