Ankle Strategy Research Articles

Understanding Vrikshasana using body mounted sensors: A statistical approach.

Aim:A scheme for understanding how the human body organizes postural movements while performing Vrikshasana is developed in the format of this paper.Settings and Design:The structural characteristics of the body and the geometry of the muscular actions are incorporated into a graphical representation of the human movement mechanics in the frontal plane. A series of neural organizational hypotheses enables us to understand the mechanics behind the hip and ankle strategy: (1) Body sway in the mediolateral direction; and (2) influence of hip and ankle to correct instabilities caused in body while performing Vrikshasana.Materials and Methods:A methodological study on 10 participants was performed by mounting four inertial measurement units on the surface of the trapezius, thoracolumbar fascia, vastus lateralis, and gastrocnemius muscles. The kinematic accelerations of three mutually exclusive trials were recorded for a period of 30 s.Results:The results of every trial were processed using two different approaches namely statistical signal processing (variance and cross-correlation). Conclusions obtained from both these studies were in favor of the initial hypothesis.Conclusions:This study enabled us to understand the role of hip abductors and adductors, and ankle extensions and flexions in correcting the posture while performing Vrikshasana.

Strategies for equilibrium maintenance during single leg standing on a wobble board

The aim of this study was to identify and compare movement strategies used to maintain balance while single leg standing on either a firm surface (FS) or on a wobble board (WB). In 17 healthy men, retroreflective markers were positioned on the xiphoid process and nondominant lateral malleolus to calculate trunk and contralateral-leg excursion (EXC) and velocity (VEL), and center of pressure (CoP) EXC and VEL during FS on a force platform. From the WB test, standing time (WBTIME) was determined and the board's angular EXC and VEL were calculated from four markers on the WB as surrogate measures for CoP dynamics. Electromyographic average rectified values (ARV) from eight leg and thigh muscles of the supporting limb were calculated for both tasks. WB ARV amplitudes were normalized with respect to the value of FS ARV and presented significantly higher peroneus longus and biceps femoris activity (p<0.05). WB standing time was correlated to trunk sagittal plane velocity (r=−0.73 at p=0.016) and excursion (r=−0.67 at p=0.03). CoP and WB angular movement measures were weakly and not significantly correlated between tasks. This lack of correlation indicates that WB balance maintenance requires movement beyond the ankle strategy as described for the FS task. WB standing likely demands different biomechanical and neuromuscular control strategies, which has immediate implications for the significance of WB tests in contrast to FS balance tests. Differences in control strategies will also have implications for the understanding of mechanisms for rehabilitation training using such devices.

Accumulative effect of ankle kinesio taping on postural control in children with hemiparetic cerebral palsy

Background and purpose Postural control deficit is one of the primary causes of impairments in hemiparetic cerebral palsy, and ankle strategy is one of the muscle synergies to control posture. The purpose of this study was to evaluate the accumulative effect of ankle taping on postural control in children with hemiparetic cerebral palsy. Patients and methods A total of 30 children participated in this study, with a mean age of 6.2 ± 0.79 years, mean weight of 25.06 ± 4.43 kg, mean height of 120.6 ± 12.33 cm, and with a degree of spasticity of 1 and 1+ according to the Modified Ashworth Scale. They were divided randomly into two groups: group A and group B. Kinesio taping was applied to the involved ankle joint for children in group B for successive 5 days/week. Rehabilitation exercises were prescribed for children in both groups three times per week for successive 12 weeks. The Biodex system was used to measure dynamic stability indexes. The measurements were carried out before and after the treatment program. Results The post-treatment results revealed a significant decrease in stability indexes in group B after 6 weeks of treatment and a significant decrease in stability indexes between the two groups before and after 12 weeks of treatment program ( P Conclusion Ankle taping has an accumulative effect on postural control and it can improve postural control in conjunction with physical rehabilitation for children with hemiparetic cerebral palsy.

Mobility Test Protocols for the Elderly: A Methodological Note.

Consequences of falls are a major health problem in elderly. Poor balance is the precursor of falls and balance impairment has been evidenced after an injury. On the other hand, balance and stability can be improved with training. At the beginning of the project Mobility in Aging one of the questions was how to measure dynamic and static balance in order to get reliable and sensitive parameters to follow the effect of decay in movement functions in elderly or to track the improvement after training. In this short report we will give a couple of answers to a long standing debate. There is indeed evidence in literature that stability and balance is very important. Elderly people often shift from the so called ankle strategy to the hip strategy for balancing. The reflex reactions are the more to decay and we observed more co-contractions. Also, inactivity causes slower muscles contractions. Our goal should be a combination of trainings, where we can see changes at neuromuscular, structural and molecular levels, but we would like to say that our training protocols did not touch all the aspects of movement function we aimed to observe. Future projects will hopefully provide the missing information.

Novel Kinetic Strategies Adopted in Asymmetric Split-Belt Treadmill Walking

ABSTRACTThe hip and ankle strategies that affect learning of a novel gait have not been fully determined, and could be of importance in design of clinical gait interventions. The authors' purpose was to determine the effects of asymmetric split-belt treadmill walking on ankle and hip work during propulsion. Participants were randomized into either a gradual training group or a sudden training group and later returned for a retention test. The gradual training group performed significantly more work at the hip joint of the slow limb during acquisition, and decreased the hip joint work performed during retention. These findings reveal the hip joint on the slow limb during initial swing as a possible site of adaptation to a novel locomotor pattern.

Postural changes associated with ageing on the sensory organization test and the limits of stability in healthy subjects.

Acknowledgement of the age effects on postural control and balance is essential to differentiate between physiological changes and actual pathological alterations of the elderly. The aim of this study is to establish the age-related postural changes recorded by the Computerized Dynamic Posturography. 70 healthy individuals (35 males and 35 females) with an average age of 44.9 years, evenly distributed in seven age groups. We carried out a Sensory Organization Test and Limits of Stability with the Neurocom Smart Balance Master(®) posturography platform. Statistical analysis was undertaken using ANOVA (p<0.05). Increased age-related balance percentage for Condition 4 (p=0.022), reduced usage rate of ankle-strategy for Conditions 3 (p=0.027) and 4 (p=0.05) for the higher age groups were reported. Regarding limits of stability, the following were the results: age-related differences at an early stage, reaction time from 40 to 49 years, velocity of movement, excursion and directional control from 50 to 59 years. Age only affects the balance rate under more complex sensory conditions. For healthy people, ankle strategy is more frequently used than hip strategy; however, the use of hip strategy increases under more difficult sensory conditions. Limits of stability get worse with age, namely after the age of 40-50 years.

Biomechanical Role of the Hip in Maintaining Balance during Standing Forward Reach

During reactions to external anterior-posterior (AP) postural perturbations, it has been demonstrated that the hip strategy (HS) is employed only when balance risk is high and the ankle strategy (AS) is inadequate. In quiet standing the ankle plays a major role in maintenance of AP balance while the role of the hip is limited to medial-lateral (ML) control. This has led to the hypothesis that use of HS during self-initiated AP movements that are relatively safe or involve small center of mass (COM) excursions indicates poor balance, possibly due to deficits in ankle musculature. Consequently, comprehensive balance tests like BESTest focus on hip strength in the frontal plane and ankle strength in the sagittal plane. PURPOSE: To elucidate the biomechanical role of the hip during self-initiated standing forward reach. This movement pattern is used in several clinical balance screens including BESTest, Berg Balance Scale and Functional Reach Test. METHODS: 5 healthy young participants stood with their right shoulder flexed to 90°. A yardstick was placed parallel to the floor at the level of the acromion. They were instructed to reach forward as far as possible without taking a step and without raising their heels off the floor. 3 trials each were collected with 2 different instructions - do not bend the hip (AS) and bend the hip (HS). 2 force plates and an 11 camera motion capture system were used to obtain joint angles and moments, and whole-body COM and center of pressure (COP) excursions. RESULTS: Reach distance normalized by height was significantly higher during HS (Δ= 4.5±1.3 cm; p=0.008). This was accompanied by a significantly higher peak hip extensor moment (Δ= 0.41±0.13 Nm/kg; p=0.014). However, the maximum COM and COP excursions and peak ankle plantarflexor moment were not significantly different between strategies. CONCLUSIONS: Using HS allowed participants to reach further without increasing the balance risk as assessed by COM and COP excursions. Based on these findings, it is likely that in a functional situation where an individual is required to reach a fixed distance, using HS will achieve the goal with smaller COP and COM excursions compared to AS. Therefore, use of HS may not necessarily be a last resort indicating absence of ankle strength and the hip should not be ignored during assessment and retraining of AP balance.

The effects of load magnitude and lifting speed on the kinematic data of load and human posture

This study examined the effects of load magnitude and lifting speed on the kinematic data of load and human posture in a lifting task. Three load magnitudes (10, 20 and 30 kg) and three lifting speeds (fast, normal and slow) were examined in this study. This study showed that participants shortened the load acceleration period on lifting a lighter load than on lifting a heavier load. For normal and slow lifting speeds, participants moved and lifted the load closer to their body when lifting a heavy load. Participants tended to maintain their postures by using an ankle strategy when in heavier load or faster lifting conditions. The profiles of angle velocity of knee and ankle joints demonstrated the important role of the lower extremities in the acceleration of the load in the initial stage of fast lifting. In addition, participants could not easily control the momentum transmitted to the ankle joint for lifting the heavy load.

Changes in balance strategy in the third trimester.

[Purpose] The purpose of this study was to elucidate changes in balance strategy during pregnancy from a kinematics perspective. [Subjects] Eight pregnant women and eight non-pregnant women participated. [Methods] A 3D motion analysis system, two force plates, and 10 infrared cameras were used to measure the kinematics of the balance strategy. The 3D motion analysis system was used to analyze performance of the functional reach test (FRT). Parameters were compared between non-pregnant women and pregnant women during each trimester, and between pregnant women in the second and third trimesters. [Results] The FRT of pregnant women was shorter than that of non-pregnant women. Bilateral hip joint extension moments were smaller in pregnant women in the second and third trimesters compared to non-pregnant women. Bilateral ankle plantar flexion moments were larger in pregnant women in their third trimester compared to non-pregnant women. In pregnant women, the right ankle plantar flexion moment was larger in the third trimester than in the second trimester. [Conclusion] These results suggest that forward reach distance is reduced, and that the ankle joint strategy takes precedence over the hip joint strategy in maintaining balance during pregnancy compared to non-pregnancy.

The effects of ankle joint strategy exercises with and without visual feedback on the dynamic balance of stroke patients.

[Purpose] The aim of this study was to examine the effects of visual feedback training on the balance of stroke patients performing ankle joint strategy exercises. [Subjects and Methods] In this study, 26 stroke patients were randomly and equally assigned to a visual feedback group (VFG) and a visual disuse group (VDG). They performed ankle joint strategy exercises for 30 minutes, three times per week for six weeks. The patients’ balance ability was measured before and after the exercises to compare the effects of visual feedback. To assess balance ability, the limits of stability (LOS) and the distance the center of pressure (CoP) moved were measured using a BT4 portable force platform. The Berg balance scale (BBS) and the timed up and go (TUG) test were also used to assess balance before and after the exercises. [Results] Changes in LOS were significant in the anterior, posterior, left, and right directions in each group, and the interactions between the two groups were significant in the posterior, left, and right directions. The changes in TUG and BBS results between pre-test and the post-test were statistically significant in the two groups, and also between the groups. [Conclusion] Visual feedback training had a positive effect on balance when ankle joint strategy exercises were performed by stroke patients to improve balance.

Analysis of foot and ankle disorders and prediction of gait in multiple sclerosis rehabilitation.

BackgroundMultiple sclerosis (MS) is a disease of the central nervous system probably based on the autoimmune mechanism against myelin and the action of lymphocyte T. In the last 50 years, more than 150 descriptive studies regarding MS have focused on the etiopathogeny, treatment, diagnosis and prevention of the progressive evolution of MS. Most recently, studies in the field of rehabilitation and diagnosis have tried to present the postural aspects of control/foot and ankle control and gait pattern in MS. The aim of this study is focused on biomechanical foot analyses of MS patients.MethodsOur clinical research and functional assessment was based on a scale like the EDSS/Kurtzke score: biomechanical foot assessment used the RSscan force plate to assess the foot loading, impulse and foot-ankle angle (subtalar angle), and pressure distribution methods for statistical analyses. The study included MS patients at the Neurologic Rehabilitation Unit, Craiova, we studied 48 patients (46.04 ± 10.99 years) diagnosed with MS.ResultsThis study shows that the major lesion is to the pyramidal system and the average value for functionality index (EDSS score) is 3.03 ± 0.13, where 3 means easy paraparesis or hemiparesis. In considering postural strategies, we observed an instability left to right to be more evident in the swing phase and it influences the under the foot impulse for the next step and postural control. From the analysis of the data and pressure centre position, we can see that the high pressure is on metatarsian II to III and more or less at the heel. This means the development of an ankle strategy necessary to restore balance, stability and motor control cannot be assessed other than by clinical evaluation.Even if many physicians and physical therapists do use the functional scale in their daily assessment, it does not help us achieve a complex assessment of gait and lower limb behaviour during gait, nor does it provide information about the impact of gait on daily activities and on quality of life.ConclusionsBiomechanical assessment can help the clinician predict the functional evolution of MS patients without visible clinical gait disorders and allows the development of a strategy for rehabilitation to prevent an incorrect ankle/ankle and foot position, resulting in a lack of motor control.

The Immediate Effects of Kinesiotm Taping on Shoulder External Rotation in People with Shoulder Pain

Objectives:Observing the immediate effect of KinesioTMTaping(KT) on dynamic balance(DB) and acceleration(ACC) of athletes and sedentary subjects.Methods:The mean ages of athletes(n=25) and sedentary(n=25) were 21,36±2,07 and 21,64±1,62 years, weight 82,36±1,75 and 79,48±7,41kg, height 1,81±0,65 and 1,77±0,56cm, and body mass index were 24,99±4,07 and 25,20±2,12kg/cm2, respectively. They were all male and students of Yeditepe University. The athletes were in the soccer and American football teams of the university. All gave their own written consent to participate in the test protocols of the study voluntarily.Their lower extremity (LE) muscle power (JTech Myometry), and the flexibility of the LE antigravity muscles were assessed before. Their DB (Prokin PK 200) of both sides, speed and acceleration in 30m sprint (Research Tracker RT6) were assessed as before and after the KT applications on both calves to observe their immediate effects on the gastrosoleus group of muscles (p<0.05). The Y shaped KT were used starting from Achilles tendon as one piece and ending over medial and lateral heads of M.Gastrocnemius. Descriptive statistics were used to understand the physical properties of the participants. Wilcoxon and Mann-Whitney-U tests were used for the significance (p< 0.05) of the data and Pearson Correlation was used to understand the relation between the data.Results:Athletes’ lower extremity muscles were stronger (p< 0.05) than the sedentary, except the M.Gluteus maximus and ankle invertors. They achieved higher performance in 30m sprint and in DB tests than the sedentary. KT on gastrosoleus group improved the DB of both sides as perimeter length(°) of the centre of pressure (COP) and the area covered (%) by COP (p< 0.05) of the athletes, but not in the ML and AP displacements (°) of COP. The athletes forward (X) and resultant (XYZ) ACC and velocity (m/sec) were significantly higher after KT application (p<0.01). The soleus, ankle invertors-evertors were effective on the forward (X) ACC, but invertors were also effective on mean velocity of the athletes, compared to sedentary.Conclusion:The athletes benefited from the immediate effects of KT application during sprinting. It increased the ability of athletes to control the movements of COP in shorter distance and smaller area compared to sedentary. Since there is no difference in AP-ML displacement of COP of both groups, we can conclude that KT does not have immediate effect on ankle strategy for DB.

Trunk muscle involvement is most critical for the loss of balance control in patients with facioscapulohumeral muscular dystrophy

BackgroundAlthough it is known that muscle weakness is a major cause of postural instability and leads to an increased incidence of falls in patients with neuromuscular disease, the relative contribution of lower extremity and trunk muscle weakness to postural instability has not been studied well. MethodsWe determined the relationship between muscle fatty infiltration and sagittal-plane balance in ten patients with facioscapulohumeral muscular dystrophy. Sagittal-plane platform translations were imposed in forward and backward directions on patients with facioscapulohumeral muscular dystrophy and healthy controls. Stepping thresholds were determined and kinematic responses and center-of-mass displacements were assessed using 3 dimensional motion analysis. In the patients, magnetic resonance imaging was used to determine the amount of fatty infiltration of trunk and lower extremity muscles. FindingsStepping thresholds in both directions were decreased in patients compared to controls. In patients, significant correlations were found for fatty infiltration of ventral muscles with backward stepping threshold and for fatty infiltration of dorsal muscles with forward stepping threshold. Fatty infiltration of the rectus abdominis and the back extensors explained the largest part of the variance in backward and forward stepping thresholds, respectively. Center-of-mass displacements were dependent on intensity and direction of perturbation. Kinematic analysis revealed predominant ankle strategies, except in patients with lumbar hyperlordosis. InterpretationThese findings indicate that trunk muscle involvement is most critical for loss of sagittal-plane postural balance in patients with facioscapulohumeral muscular dystrophy. This insight may help to develop rehabilitation strategies to prevent these patients from falling.

Postural strategies assessed with inertial sensors in healthy and parkinsonian subjects

The present study introduces a novel instrumented method to characterize postural movement strategies to maintain balance during stance (ankle and hip strategy), by means of inertial sensors, positioned on the legs and on the trunk.We evaluated postural strategies in subjects with 2 types of Parkinsonism: idiopathic Parkinson's disease (PD) and Progressive Supranuclear Palsy (PSP), and in age-matched control subjects standing under perturbed conditions implemented by the Sensory Organization Test (SOT). Coordination between the upper and lower segments of the body during postural sway was measured using a covariance index over time, by a sliding-window algorithm. Afterwards, a postural strategy index was computed. We also measured the amount of postural sway, as adjunctive information to characterize balance, by the root mean square of the horizontal trunk acceleration signal (RMS). Resultsshowed that control subjects were able to change their postural strategy, whilst PSP and PD subjects persisted in use of an ankle strategy in all conditions. PD subjects had RMS values similar to control subjects even without changing postural strategy appropriately, whereas PSP subjects showed much larger RMS values than controls, resulting in several falls during the most challenging SOT conditions (5 and 6). Results are in accordance with the corresponding clinical literature describing postural behavior in the same kind of subjects.The proposed strategy index, based on the use of inertial sensors on the upper and lower body segments, is a promising and unobtrusive tool to characterize postural strategies performed to attain balance.

편마비 환자의 발목관절 전략 운동이 균형 조절 능력에 미치는 영향

PURPOSE: PURPOSE: The purpose of this study was to analyze the effect and examine the feasibility of an intervention of ankle strategy exercise on balance of patients with hemiplegia. METHODS: The subject were randomly allocated to three groups: ankle strategy exercise (group A), balance exercise (group B) and control (group C). Group A was received the conventional physical therapy plus ankle strategy exercises for 20 minutes in one session. Group B was received the same conventional physical therapy plus balance exercises for 20 minutes in one session. Two active groups were performed in the session 3 times a week, for a total of 6 weeks. and Group C was only received the same conventional physical therapy. Balance test was assessed using center of pressure (COP) in the anteroposterior (A-P), mediolateral (M-L) direction, Berg balance scale (BBS) and Timed Up and Go Test (TUG). RESULTS: All groups showed improvements in balance parameters. In especial, the Group A was statistically significant differences in almost part evaluation items and showed more improvements in BBS and TUG parameters than Group B and Group C. and moving distance of M-L COP was more improvements than Group B. CONCLUSION: Ankle strategy exercises had more influence on balance than balance exercises and neurodevelopmental treatment.

People with recurrent ankle sprains do not change their ankle strategy in anticipation of a perturbation event

Methods Two groups of participants were recruited: 14 with no history of ankle injury (age 22.6 ± 0.7 yrs, 10 females) and 14 with a history of two or more ankle sprains (Age 21.1 ± 0.2 yrs, 9 females, 6 ± 2.5 sprains). Participants stood in single leg stance on an inversion perturbation platform. The perturbation platform dropped 15 degrees in the frontal plane on a trigger activated by the researcher. Movement Oscillation at the ankle was measured via a 3Space fastrak (Polhemius Ltd) with a receiver taped one cm above the lateral malleolus. Oscillation was determined as the standard deviation of the movement in the frontal plane (mm) measured over 10s while the platform was horizontal. Three conditions were investigated: standing with no change in the platform, standing with a 15 deg drop occurring at a specified time, and standing with a drop occurring at anytime. Data were compared between groups using a Mann-Whitney U test, as the data were not normally distributed.

A bidirectional model of postural sway using force plate data.

This work was designed to expand on our previous anterior-posterior postural control model to include medial-lateral sway of unperturbed posture during quiet standing. The bidirectional model simulates two decoupled inverted pendulums, each restricted to sway in either the anterior-posterior (AP) direction (ankle strategy) or medial-lateral (ML) direction (hip strategy), and each controlled by a Proportional-Integral-Derivative (PID) controller. Postural data was collected from 31 healthy participants under different sensory test conditions: eyes closed, eyes open, and eyes open with real-time visual feedback. Simulation iterations of the bidirectional model were run for each sensory test condition to adjust the PID controller parameters until modeled sway metrics did not differ significantly from experimental metrics at p ≤ 0.01. Simulations did not show significant changes in the AP sway controller parameters among the 3 sensory test conditions. The model did show significant changes in ML sway controller parameters, namely stiffness and time delay. Significant differences were also seen in the experimental sway metrics under the three different sensory test conditions. The multi-sensory evaluation and bidirectional sway model offer unique insight for further exploration of postural pathology, control mechanisms and planar coupling that includes both ankle and hip strategies.

Postural responses during the various frequencies of anteroposterior perturbation.

This study investigated the characteristics of dynamic postural responses when subjects attempted to maintain an upright standing position on a support plate during continuous sinusoidal perturbation in the anterior-posterior direction. Fifteen healthy young subjects participated in the experiment. Body movement patterns during the perturbation were captured and analyzed using a 3D motion analysis system (APAS 3D motion analysis, Ariel Dynamics Inc.). Seven markers were attached on the subject's body to measure and analyze the motion patterns. The markers were positioned at the head, chest, hip, right knee, left knee, right ankle, and left ankle. Five different frequencies of motion were applied to the support surface: 0.1, 0.5, 1.0, 1.5, and 2.0 Hz with a 4-cm path of motion at the base. The experiments measured dynamic postural responses in a condition were subjects had their eyes open. The results showed that the median frequency of the knee and ankle increased in all frequency bands. Following an increase in the frequency of the perturbation, the postural control strategy was changed from the ankle strategy to a combined strategy. These experimental results could be applied to the dynamic postural training for the elderly and to rehabilitation training for patients to improve their ability for postural control.

Individuals with diminished hip abductor muscle strength exhibit altered ankle biomechanics and neuromuscular activation during unipedal balance tasks

Coordinated control of the hip and ankle is important for maintaining postural stability. The purpose of the study was to compare postural stability between individuals with contrasting hip abductor strength during unipedal balance tasks and to determine whether diminished hip abductor strength results in greater utilization of the ankle strategy to maintain balance. Forty-five females (276±35 years) participated in the study. Participants were ranked based on their isometric hip abductor muscle strength. The top 33% of the participants were categorized as the strong group (n=15) and the lower 33% as the weak group (n=15). Each subject performed a static and a dynamic unipedal balance task, during which mean COP displacement, peak ankle invertor and evertor moments, and neuromuscular activation of the lower leg muscles were assessed. Two-way mixed analyses of variance tests with task as a repeated factor were performed to detect the effects of task and group on the variables of interest. When averaged across tasks, mean medial-lateral COP displacement was significantly greater in the weak group (136±117 vs. 98±60mm, p=0.05). The weak group also exhibited greater peak ankle invertor and evertor moments (0.31±0.10 vs. 0.25±0.11Nm/kg, p=0.03; 0.04±0.06 vs. −0.02±0.07Nm/kg, p=0.01), and increased peroneus longus activation (46±12 vs. 36±15%, p<0.01). Our results demonstrate that individuals with diminished hip abductor muscle strength demonstrated decreased medial-lateral postural stability, and exhibited a shift toward utilizing an ankle strategy to maintain balance during unipedal tasks.

The Influence of Foot Sizes on Human Balance

This study investigated the relationship between foot size and human balance performance. The balance performances of 30 female subjects (15 young, 15 elderly) were assessed by a force platform system. Mean sway velocity, balance strategy score and composite equilibrium score (CES) were used to quantify balance performances from three different aspects. Correlation analysis was conducted to analyze the relationship between foot sizes and human balance measures. The results showed that most foot size measures (with or without normalizations) have significant correlations on mean sway velocity and balance strategy score, but no relationship with CES. In general, the bigger the foot size, the lower mean sway velocity and the bigger the normalized foot size, the higher balance strategy score (more ankle strategy), especially for the young group.