Ankle Dorsiflexion Angle Research Articles

Frontal plane projection angle predicts patellofemoral pain: Prospective study in male military cadets

BackgroundPatellofemoral pain (PFP) is a major source of knee pain. Identifying who may develop PFP is of paramount importance. PurposeTo assess whether Frontal plane projection angles (FPPA) and hand held dynamometry (HHD) strength measures can predict development of PFP. Study designProspective evaluation of individuals undertaking a military training programme. MethodsMale military recruits were enrolled and prospectively followed up from enrolment to completion of 12-weeks training. Lower limb kinematics (FPPA, Q-angle, hip adduction angle, knee flexion, ankle dorsiflexion, and rearfoot eversion angle) measured during running, single leg squatting (SLS), and single leg landing (SLL) and isometric muscle strength of hip abductors and knee extensors. ResultsBody mass, hip abductor muscle strength, Q-angle during SLS and SLL, FPPA during SLL all significantly different between the PFP and non-injured groups and predicted PFP, highest predictor variable was FPPA during SLL (Odds Ratio = 1.13, P = 0.01). A FPPA≥5.2° during SLL predicting PFP with a sensitivity of 70% and a specificity of 70%. ConclusionParticipants who developed PFP had a number of physical factors significantly different than the non-injured group, most predictive was a larger FPPA during SLL, with angles greater than 5.2° associated with a 2.2x greater risk. Clinical relevanceAssessing FPPA during SLL could be used to determine who was predisposed to PFP.

The effect of fatigue on the ankle and knee kinematics and kinetics in moderately and highly trained healthy non-rearfoot runners

ABSTRACT The aim of this study was to compare selected ankle and knee kinematic and kinetic parameters before and after a prolonged exhaustive treadmill run between two groups of non-rearfoot footstrike pattern (NRFP) runners with different training volumes. Twenty-eight habitual NRFP runners were assigned to two groups based on their weekly training volume (Highly-trained (HT)/Moderately-trained (MT)). Participants underwent the VO2max test, and the exhaustive treadmill ran with biomechanical analysis at the beginning and the end. The two-way RMANOVA was used to assess differences between the groups and the phase of the run. A paired t-test was used for post-hoc analysis in case of significant interaction effect. Kinetic results showed significant group effect for ankle plantarflexion moment and hip external rotation moment (end-phase: both greater in MT group). Kinematic results showed significant group×phase interaction for ankle dorsiflexion angle (end-phase: greater in MT group) at initial contact (IC), peak knee flexion angle (end-phase: greater in MT group), and peak ankle eversion angle during the stance phase (end-phase: greater in HT group). Additionally, a group effect was found for knee flexion angle at IC (end-phase: greater in HT group). This study suggests that HT healthy NRFP runners may have less potential for increased biomechanical risk of AT overload during an exhaustive run.

Effects of movement direction and limb dominance on ankle muscular force in sidestep cutting.

Sidestep cutting is a critical movement in sports. However, biomechanical research on sidestep cutting has not hitherto reached a consensus. In order to investigate the effects of limb dominance and movement direction on ankle and subtalar joints during sidestep cutting, twelve physically active male participants were recruited in the present study. Trajectory and ground reaction force data were collected by the motion capture system and force platform. Kinematics, kinetics, and muscle forces information were obtained by running OpenSim. Two-way repeated measures ANOVA was performed with movement direction and limb dominance as independent variables. We found that movement direction had a significant effect on ankle dorsiflexion angle. In contrast, the factor of limb dominance had no effect on ankle and subtalar joints angles. For ankle joint moment, the plantarflexion moment was greater by performing a 45° sidestep cutting or using the dominant limb, while the subtalar joint moment was not affected by these two variables. In terms of muscle forces, the soleus of the dominant limb generated greater plantarflexion muscle force on the sagittal plane, while the non-dominant limb tended to contract more strongly (peroneus longus and peroneus brevis) on the frontal plane to stabilize the subtalar joint. Meanwhile, a smaller sidestep cutting angle made participants generate greater plantarflexion muscle forces (soleus and gastrocnemius). In conclusion, our findings indicated that participants should take limb dominance and movement direction into consideration for enhancing athletic performance and reducing the risk of injury during sidestep cutting.

Biomechanical Characteristics and Metabolic Efficiency of Gait in Young-old and Old-old People

<h3>Research Objectives</h3> To investigate and compare the biomechanical characteristics and cardiopulmonary metabolic energy efficiency of gait between the young-old and the old-old community dwelling people. <h3>Design</h3> Cross-sectional study. <h3>Setting</h3> Clinical experimental study. <h3>Participants</h3> The elderly participants (N=78) were classified into the young-old (age range=65-74, mean age=70.2 ± 2.8 years, n=44) and the old-old (age range=75-84, mean age=77.9 ± 2.2 years, n=34) groups. <h3>Interventions</h3> Not applicable. <h3>Main Outcome Measures</h3> Spatiotemporal parameters (gait speed, cadence, step length, step width, and stride length), kinematics (angle of hip, knee, and ankle joint), kinetics (moment and power of hip, knee, and ankle joint), and cardiopulmonary metabolic energy efficiency during gait. <h3>Results</h3> Spatiotemporal gait parameters (gait speed, step length, and stride length) were significantly decreased in the old-old compared to the young-old group (p < 0.01). Peak ankle dorsiflexion angle, peak moment and peak power of knee and hip joints during gait were also significantly decreased in the old-old compared to the young-old group (p < 0.05, p < 0.01). On the other hand, net cardiopulmonary metabolic energy cost showed no significant difference between groups. <h3>Conclusions</h3> The old-old and young-old people showed significantly different gait characteristics, which suggested a need of customized intervention strategy in two elderly groups for preventing age-related hazardous condition such as fall. <h3>Author(s) Disclosures</h3> Eunhye Chung1,2, Su-Hyun Lee2, and Yun-Hee Kim1,2,3 1. Department of Medical Device Management & Research, SAIHST, Sungkyunkwan University, SAIHST, Seoul, Republic of Korea 2. Department of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea 3. Department of Health Sciences and Technology, Department of Digital Health, Sungkyunkwan University, SAIHST, Seoul, Republic of Korea

Biomechanical Analysis of the FlatFoot with Different 3D-Printed Insoles on the Lower Extremities

Insoles play an important role in the conservative treatment of functional flat foot. The features of 3D-printed insoles are high customizability, low cost, and rapid prototyping. However, different designed insoles tend to have different effects. The study aimed to use 3D printing technology to fabricate three different kinds of designed insoles in order to compare the biomechanical effects on the lower extremities in flat foot participants. Ten participants with functional flat foot were recruited for this study. Data were recorded via a Vicon motion capture system and force plates during walking under four conditions: without insoles (shoe condition), with auto-scan insoles (scan condition), with total contact insoles (total condition), and with 5-mm wedge added total contact insoles (wedge condition). The navicular height, eversion and dorsiflexion angles of the ankle joint, eversion moment of the ankle joint, and adduction moment of the knee joint were analyzed, and comfort scales were recorded after finishing the analysis. Compared to the shoe condition, all three 3D printed insoles could increase the navicular height and ankle dorsiflexion angle and improve comfort. Among the three insoles, the wedge condition was the most efficient in navicular height support and increasing the ankle dorsiflexion angle.

The Management of Toe Walking in Children with Autism Spectrum Disorder: "Cast and Go".

Background: Toe walking is associated with autism spectrum disorders (ASD). Correction of this “behavior” is a health challenge. The toe walker is affected by the contact refusal with the outside world: touching the ground as little as possible, trying to avoid any contact. A structured equines foot is a possible consequence. Method: We present the “Cast and Go” protocol, used in 22 idiopathic toe walker children with ASD treated from 2015 to 2020. The treatment was performed by a single senior experienced doctor with botulinum injection, ankle casts and rehabilitative therapies. All patients underwent pre- and post-treatment clinical evaluation using ankle dorsiflexion angle and casting number as treatment. We aimed to identify the intervention with the shortest acquisition time for the management of toe walking. Results: Our findings demonstrated the baseline ankle dorsiflexion angle influenced the casting number (p < 0.01) and male patients had a higher baseline ankle dorsiflexion angle than female patients (p < 0.01). No adverse events were observed. Conclusions: These findings suggested that the “Cast and Go” protocol could be a promising, dynamic and effective practice for toe walking disease in ASD patients.

Robotic ankle control can provide appropriate assistance throughout the gait cycle in healthy adults.

Ankle foot orthoses are mainly applied to provide stability in the stance phase and adequate foot clearance in the swing phase; however, they do not sufficiently assist during the entire gait cycle. On the other hand, robotic-controlled orthoses can provide mechanical assistance throughout the phases of the gait cycle. This study investigated the effect of ankle control throughout the gait cycle using an ankle joint walking assistive device under five different robotic assistance conditions: uncontrolled, dorsiflexion, and plantar flexion controlled at high and low speeds in the initial loading phase. Compared with the no-control condition, the plantar flexion condition enhanced knee extension and delayed the timing of ankle dorsiflexion in the stance phase; however, the opposite effect occurred under the dorsiflexion condition. Significant differences in the trailing limb angle and minimum toe clearance were also observed, although the same assistance was applied from the mid-stance phase to the initial swing phase. Ankle assistance in the initial loading phase affected the knee extension and ankle dorsiflexion angle during the stance phase. The smooth weight shift obtained might have a positive effect on lifting the limb during the swing phase. Robotic ankle control may provide appropriate assistance throughout the gait cycle according to individual gait ability.

Optimal and suboptimal video instructions change movement execution in young talented basketball players

Observational learning is considered powerful to promote (implicit) motor learning. While it is a common tool in practice, little is known about the effects of video instructions on movement execution. The aim of this study was to investigate the effects of watching biomechanically optimal (OPT) and suboptimal (SUBOPT) sidestep cutting (SSC) video instructions on movement execution. Ten male basketball players (age 15.5 ± 1.2 years, height 189.9 ± 3.1 cm, mass 75.4 ± 7.1 kg) from a Regional Talent Center performed anticipated 45° SSC tasks in baseline (BASE) followed by two counterbalanced experimental conditions. Subjects watched expert videos (matched by sex and height) of OPT and SUBOPT movement executions and were asked to imitate this to the best of their ability. Kine(ma)tic data was captured with 21 reflective markers and 2 force plates. After watching the videos, subjects displayed smaller ankle dorsiflexion angles ( p &lt; 0.001) and greater vertical ground reaction force (vGRF) ( p = 0.012) in SUBOPT compared to OPT condition during initial contact (IC). Greater knee flexion and ankle dorsiflexion angles in the expert compared to subjects in the OPT condition were found ( p &lt; 0.001). Contrarily, subjects were able to imitate SUBOPT executions shown by the expert. This means that athletes worsen their movement execution when modelling a SUBOPT model. Coaches are advised to mainly use (1) OPT video instructions and (2) expert modelling with a relatively small gap in movement execution between the athlete and model.

How Ankle Exoskeleton Assistance Affects the Mechanics of Incline Walking and Stair Ascent in Cerebral Palsy.

Graded terrains, like slopes and stairs, are particularly challenging for people with neurological disorders like cerebral palsy (CP) due to increased selective muscle control and muscle strength requirements. Lower-limb exoskeletons may be able to assist individuals with CP when navigating graded terrains. This study sought to determine the effects of untethered ankle exoskeleton assistance on lower-limb joint angles, moments, and muscle activity during up-incline walking and up-stair stepping in CP (n=7). We hypothesized that powered assistance would result in improved ankle mechanics (i.e., increased total ankle moments) across both terrains. During incline walking, we found that peak ankle dorsiflexion angle increased by $7^{\mathrm{o}}$(p=0.006) during walking with ankle assistance compared to walking without the device (Shod). Compared to without the device, the peak total ankle plantarflexor moment increased by 8% (p=0.022) while peak biological ankle plantarflexor moment decreased by 17% (p< 0.001). Incline walking with ankle assistance reduced stance phase muscle activity of the soleus (20%, p=0.010) and vastus lateralis (18%, p=0.004), and swing phase tibialis activity (19%, p=0.028) compared to Shod. During stair ascent with the device, the peak total ankle plantarflexor moment increased by 17% (p=0.011) and the peak knee extensor moment increased by 40% (p=0.018) compared to Shod. These findings provide insight into the biomechanical benefits of ankle exoskeleton assistance during incline and stair walking. This work aims to advance the use of robotic assistive technology to improve mobility for people with CP.

The center of pressure position in combination with ankle dorsiflexion and trunk flexion is useful in predicting the contribution of the knee extensor moment during double-leg squatting

BackgroundSquatting exercises are commonly used in rehabilitation for knee joint disorders; in these exercises, control of knee extensor moment is important to enhance training effects and to avoid adverse effects. Ankle dorsiflexion and trunk flexion are widely used to reduce knee extensor moments during squatting, but the increased load on the low back is a concern. The purpose of this study was to determine whether the anterior–posterior (AP) center-of-pressure (COP) position and the AP-COP position in combination with ankle dorsiflexion and trunk flexion angles can predict the contribution of the knee extensor moment during double-leg squatting.MethodsTwenty-eight healthy individuals (14 female and 14 male participants, age 22.8 ± 1.3 years) performed three sets of five consecutive double-leg squats. Kinematics and kinetics were analyzed using a three-dimensional motion analysis system with force plates. Univariate and multivariate regression analyses were performed to predict the contribution of the knee extensor moment (% total support moment) from AP-COP position, ankle dorsiflexion, and trunk flexion.ResultsThe AP-COP position was a significant predictor of the knee extensor moment contribution (R2 = 0.168, P = 0.030). Multivariate analysis showed that the ankle dorsiflexion angle (ΔR2 = 0.561, β = 0.842) and AP-COP position (ΔR2 = 0.296, β = − 0.499) predicted the knee extensor moment contribution (model R2 = 0.857, P < 0.001). Additionally, the combination of trunk flexion (ΔR2 = 0.429, β = − 0.613) and AP-COP position (ΔR2 = 0.109, β = − 0.332) predicted the knee extensor moment contribution (model R2 = 0.538, P < 0.001). The limb symmetry index of the knee extensor moment was significantly associated with that of the AP-COP position (R2 = 0.493, P < 0.001) but not with that of the ankle dorsiflexion angle (P = 0.057).ConclusionsThe AP-COP position can predict the contribution of the knee extensor moment and improve the prediction when combined with ankle dorsiflexion and trunk flexion. The present findings suggest that intervention focusing on the AP-COP position in combination with ankle dorsiflexion or trunk flexion would be useful to coordinate the contribution of the knee extensor moment during double-leg squatting.

Effect of Heel Lift Insoles on Lower Extremity Muscle Activation and Joint Work during Barbell Squats.

The effect of heel elevation on the barbell squat remains controversial, and further exploration of muscle activity might help find additional evidence. Therefore, 20 healthy adult participants (10 males and 10 females) were recruited for this study to analyze the effects of heel height on lower extremity kinematics, kinetics, and muscle activity using the OpenSim individualized musculoskeletal model. One-way repeated measures ANOVA was used for statistical analysis. The results showed that when the heel was raised, the participant’s ankle dorsiflexion angle significantly decreased, and the percentage of ankle work was increased (p < 0.05). In addition, there was a significant increase in activation of the vastus lateralis, biceps femoris, and gastrocnemius muscles and a decrease in muscle activation of the anterior tibialis muscle (p < 0.05). An increase in knee moments and work done and a reduction in hip work were observed in male subjects (p < 0.05). In conclusion, heel raises affect lower extremity kinematics and kinetics during the barbell squat and alter the distribution of muscle activation and biomechanical loading of the joints in the lower extremity of participants to some extent, and there were gender differences in the results.

Effects of flat-flexible shoes on lower limb joint kinetics and kinematics in gait

Flat-flexible shoes with unique characteristics, such as low pitch and flexibility, can increase the efficiency of ankle energy and running performance. If flat-flexible shoes have the same effect during walking, they could be used for gait training. This study aimed to investigate the effects of flat-flexible shoes on the kinematics and kinetics of the lower limb. Twenty-one healthy young adults (21.8 ± 4.6 years) participated in this study. The participants wore flat-flexible and standard athletic shoes with reflective markers attached according to the Plug-in-Gait model. Walking motion was recorded using infrared cameras and a treadmill embedded with force plates. The angle(s), moment(s), and power(s) of the ankle, knee, and hip joints were calculated. Paired t-test and Wilcoxon’s signed-rank test were used to compare the parameters between the two footwear types. The use of flat-flexible shoes increased maximum ankle dorsiflexion and knee flexion angles. The maximum ankle plantar flexion angle was significantly reduced. There was no significant difference in the joint moment between the two footwear types. The peaks of ankle power absorption in late stance, ankle power generation, and hip power generation significantly increased with the use of flat-flexible shoes. These results suggest that flat-flexible shoes have potential as a tool to promote ankle energy storage and release during gait.

Biomechanics analysis of seven Tai Chi movements

This study examined the maximum joint angles and moments, and electromyography (EMG) activity of the lower limbs in an experienced Tai Chi (TC) practitioner in performing four dynamic (Repulse Monkey, Wave-hand in Clouds, Brush Knee Twist Step, and Lateral Forward Step) and three static TC movements (Starting Form, Hero Touch Sky, and Push Hand Back) and compared them with the measures from walking. Integrated EMG (iEMG) and peak EMG of the rectus femoris, adductor longus, tibialis anterior, semitendinosus, erector spinae, gluteus medius, tensor fasciae latae, medial and lateral gastrocnemius muscles were analyzed. One-way analysis of variance showed that compared with walking, TC presented 1) significantly larger hip flexion (71.4° vs. 42.2°) and abduction angles (11.9° vs. 5.3°), smaller knee flexion (45.2° vs. 71.1°) and abduction angles (13.0° vs. 27.7°), larger ankle dorsiflexion (41.4° vs. 11.3°) and abduction angles (8.8° vs. 7.2°); 2) hip flexion moment and knee flexion and abduction moment were significantly larger. Ankle dorsiflexion moment were significantly smaller, whereas ankle abduction moment was significantly larger in two TC movements; and 3) the EMG activity of the muscles in TC varied from 10% to 610% of walking. The knee extensors, hip adductors and abductors had significantly higher peak EMG (430% ​± ​40%, 240% ​± ​30%, and 320% ​± ​90%) and iEMG values (610% ​± ​30%, 311% ​± ​30%, and 1.4% ​± ​20%), respectively. The findings suggested that these TC movements could be a good option for the improvement of muscle strength and range of motion of the lower limbs.

Rabbit hindlimb kinematics and ground contact kinetics during the stance phase of gait.

Though the rabbit is a common animal model in musculoskeletal research, there are very limited data reported on healthy rabbit biomechanics. Our objective was to quantify the normative hindlimb biomechanics (kinematics and kinetics) of six New Zealand White rabbits (three male, three female) during the stance phase of gait. We measured biomechanics by synchronously recording sagittal plane motion and ground contact pressure using a video camera and pressure-sensitive mat, respectively. Both foot angle (i.e., angle between foot and ground) and ankle angle curves were unimodal. The maximum ankle dorsiflexion angle was 66.4 ± 13.4° (mean ± standard deviation across rabbits) and occurred at 38% stance, while the maximum ankle plantarflexion angle was 137.2 ± 4.8° at toe-off (neutral ankle angle = 90 degrees). Minimum and maximum foot angles were 17.2 ± 6.3° at 10% stance and 123.3 ± 3.6° at toe-off, respectively. The maximum peak plantar pressure and plantar contact area were 21.7 ± 4.6% BW/cm2 and 7.4 ± 0.8 cm2 respectively. The maximum net vertical ground reaction force and vertical impulse, averaged across rabbits, were 44.0 ± 10.6% BW and 10.9 ± 3.7% BW∙s, respectively. Stance duration (0.40 ± 0.15 s) was statistically significantly correlated (p < 0.05) with vertical impulse (Spearman’s ρ = 0.76), minimum foot angle (ρ = −0.58), plantar contact length (ρ = 0.52), maximum foot angle (ρ = 0.41), and minimum foot angle (ρ = −0.30). Our study confirmed that rabbits exhibit a digitigrade gait pattern during locomotion. Future studies can reference our data to quantify the extent to which clinical interventions affect rabbit biomechanics.

Effects of Changing Center of Pressure Position on Knee and Ankle Extensor Moments During Double-Leg Squatting.

The effects of changes in the anterior-posterior center of pressure (AP-COP) position on the lower limb joint moments during double-leg squatting remain unclear. The purpose of this study was to determine the effects of AP-COP positional changes on the hip, knee, and ankle extensor moments during double-leg squatting. Sixteen male participants (22.1 ± 1.5 years) performed double-leg squatting under two conditions (anterior and posterior COP conditions) with visual feedback on their COP positions. Kinematics and kinetics were analyzed using a three-dimensional motion analysis system and force plates. The hip, knee and ankle flexion angles and extensor moments at peak vertical ground reaction force were compared between the two conditions using paired t tests. The COP position was 53.5 ± 2.4% of the foot length, starting from the heel, under the anterior condition and 44.4 ± 2.1% under the posterior condition (P < 0.001). The knee extensor moment was significantly smaller under the anterior than the posterior COP condition (P = 0.003, 95% confidence interval (CI) -0.087 to -0.021 Nm/kg/m), while the ankle extensor moment significantly larger under the anterior COP condition than under the posterior COP condition (P < 0.001, 95% CI 0.113 to 0.147 Nm/kg/m). There was no significant difference in hip extensor moment (P = 0.431). The ankle dorsiflexion angle was significantly larger under the anterior than the posterior COP condition (P = 0.003, 95% CI 0.6 to 2.6°), while there was no difference in trunk, hip, or knee flexion angle. The present results indicate that changes in the AP-COP position mainly affect the ankle and knee extensor moments during double-leg squatting, while the effect on the lower limb joint and trunk flexion angles was limited. Visual feedback on the AP-COP position could be useful for modifying the ankle and knee extensor moments during double-leg squatting.

Effect of the Innovative Running Shoes With the Special Midsole Structure on the Female Runners’ Lower Limb Biomechanics

The study aimed to research the effects of innovative running shoes (a high heel-to-toe drop and special structure of midsole) on the biomechanics of the lower limbs and perceptual sensitivity in female runners. Fifteen healthy female runners were recruited to run through a 145-m runway with planted force plates at one peculiar speed (3.6 m/s ± 5%) with two kinds of shoe conditions (innovative running shoes vs. normal running shoes) while getting biomechanical data. The perception of shoe characteristics was assessed simultaneously through a 15-cm visual analog scale. The statistical parametric mapping technique calculated the time-series parameters. Regarding 0D parameters, the ankle dorsiflexion angle of innovative running shoes at touchdown was higher, and the peak dorsiflexion angle, range of motion, peak dorsiflexion velocity, and plantarflexion moment on the metatarsophalangeal joint of innovative running shoes during running were significantly smaller than those of normal running shoes (all p < 0.001). In addition, the braking phase and the time of peak vertical force 1 of innovative running shoes were found to be longer than those of normal running shoes (both p < 0.05). Meanwhile, the average vertical loading rate 1, peak vertical loading rate 1, peak braking force, and peak vertical force 1 in the innovative running shoes were lower than those of the normal running shoes during running (both p < 0.01). The statistical parametric mapping analysis exhibited a higher ankle dorsiflexion angle (0–4%, p < 0.05), a smaller knee internal rotation angle (0–6%, p < 0.05) (63–72%, p < 0.05), a decreased vertical ground reaction force (11–17%, p = 0.009), and braking anteroposterior ground reaction force (22–27%, p = 0.043) for innovative running shoes than normal running shoes. Runners were able to perceive the cushioning of innovative running shoes was better than that of normal running shoes. These findings suggested combining the high offset and structure of the midsole would benefit the industrial utilization of shoe producers in light of reducing the risk of running injuries for female runners.

Greater heel-rise endurance is related to better gait biomechanics in patients surgically treated for chronic Achilles tendon rupture

PurposeTo determine the relationships among calf muscle function, tendon length and gait biomechanics in patients surgically treated for chronic Achilles tendon rupture.MethodsTwenty-one patients with chronic Achilles tendon rupture (mean age 62 ± 13 years) were evaluated by heel-rise endurance test, Achilles Tendon Resting Angle (ATRA), ultrasound measurement of tendon length and three-dimensional gait analysis. A bivariate two-sided correlation test was performed on all variables in all patients.ResultsBetter performance across all parameters of the heel-rise endurance test correlated with faster walking speed (r = 0.52–0.55), greater peak ankle power (r = 0.56–0.64), shorter stance phase (r = −0.52 to −0.76) and less peak ankle dorsiflexion angle (r = −0.49 to −0.64) during gait. Greater ATRA correlated with longer stance time (r = 0.47), greater peak ankle dorsiflexion angle (r = 0.48), less heel-rise repetitions (r = −0.52) and less heel-rise total work LSI (r = −0.44 to −0.59).ConclusionGreater calf muscle endurance, especially heel-rise total work, is moderately correlated (r = 0.49–0.76) to better ankle biomechanics during gait in patients surgically treated for CATR. The heel-rise endurance test may be a clinical proxy for power development in the ankle joint during gait.Level of evidenceIV.

Reduced plantar-flexors extensibility but improved selective motor control associated with age in young children with unilateral cerebral palsy and equinovalgus gait

BackgroundChildren with spastic cerebral palsy gradually lose muscle extensibility but the interplay between the muscular and neurological components of the condition is unclear especially in the pathophysiology of equinovalgus gait. AimThis study aimed to quantify the muscular and neurological disorders in young children with unilateral cerebral palsy, and to investigate the role of the peroneus longus (PL) in equinovalgus gait.Design, setting and population: This was an observational study with prospective assessments of 31 children (median age: 2.9 years, range: 2–6) from outpatient clinic in a tertiary teaching hospital. MethodsClinical measures of plantar flexor extensibility (XV1), stretch response (XV3), and active ankle dorsiflexion angle (XA) were obtained as well as walking velocity and electromyography of tibialis anterior (TA), gastrocnemius medialis (GM) and PL during walking. ResultsWe found reduced extensibility of the triceps surae on the paretic side (effect size r = 0.73, p < 0.001 for soleus and r = 0.68, p < 0.001 for gastrocnemius) and a correlation between reduced triceps surae extensibility and earlier stretch response (ρ = 0.5, p = 0.004). During the swing phase, there was major co-contraction between TA and GM/PL, and significantly larger activation of PL compared to GM (r = 0.46, p = 0.011). Both GM and PL activation decreased with age. ConclusionsOur results suggest gradual deterioration of the muscular disorder and a link between the muscular and neurological disorders, although plantar flexor co-contraction improved with age. The PL was more activated than the GM and may be considered an intervention target to treat equinovalgus gait.

Dorsiflexion and Hop Biomechanics Associate with Greater Talar Cartilage Deformation in Those with Chronic Ankle Instability.

This study aimed to identify associations between dorsiflexion range of motion (DFROM), functional hop test performance, and hopping biomechanics with the magnitude of talar cartilage deformation after a standardized hopping protocol in individuals with and without chronic ankle instability (CAI). Thirty CAI and 30 healthy individuals participated. Ankle DFROM was assessed using the weight-bearing lunge test. Four different functional hop tests were assessed. Three-dimensional kinematics and kinetics were sampled during a 60-cm single-leg hop. We calculated cartilage deformation after a dynamic loading protocol consisting of sixty 60-cm single-leg forward hops by assessing the change in average thickness for the overall, medial, and lateral talar cartilage. Linear regressions examined the associations between cartilage deformation magnitude and DFROM, functional hop tests, and hop biomechanical variables after accounting for body weight and time since the initial ankle sprain. In CAI group, lesser static DFROM (ΔR2 = 0.22) and smaller peak ankle dorsiflexion angle (ΔR2 = 0.17) was associated with greater medial deformation. Greater peak vertical ground reaction force (vGRF) (ΔR2 = 0.26-0.28) was associated with greater medial and overall deformation. Greater vGRF loading rate (ΔR2 = 0.23-0.35) was associated with greater lateral and overall deformation. Greater side hop test times (ΔR2 = 0.31-0.36) and ankle plantarflexion at initial contact (ΔR2 = 0.23-0.38) were associated with greater medial, lateral, and overall deformation. In the control group, lesser side hop test times (ΔR2 = 0.14), greater crossover hop distances (ΔR2 = 0.14), and greater single-hop distances (ΔR2 = 0.21) were associated with greater overall deformation. Our results indicate that lesser static DFROM, poorer functional hop test performance, and hop biomechanics associate with greater talar cartilage deformation after a dynamic loading protocol in those with CAI. These factors may represent targets for therapeutic interventions within this population to slow ankle posttraumatic osteoarthritis progression.

Effects of Soccer Exercise on Balance Ability and Kinesthesia of the Lower Limb Joints in Children Aged 5-6 Years.

Age-, height- and weight-matched children were recruited to the experimental group (EG; n = 31) and control group (n = 32). Following a 16-week soccer training program, balance ability and dominant-side lateral knee and ankle kinesthesia changes were tested. Regarding balance ability, the Sway Index, when children stood on a firm or foam surface with their eyes closed in the static balance test, and the dynamic balance test time were 13.5%, 11.6%, and 14.3% lower in the EG than in the control group, respectively. The scores in the left and right directions were 23.7% and 24.2% higher in the EG, respectively. Regarding kinesthesia, the angle of knee extension and ankle metatarsal flexion and dorsiflexion were 13.4%, 20.0%, and 16.8% lower in the EG than in the control group. These results indicate children in the EG had a better performance. After soccer exercise, children aged 5-6 years displayed improved balance in the left and right directions and improved knee extension, ankle plantarflexion, and dorsiflexion kinesthesia.