The effect of lateral or medial wedges on control of postural sway in standing

Does medial calcaneal wedge improve static balance and load distribution in young adults with pronated foot?

BACKGROUND

Foot orthoses changing the momentum in the subtalar joint are often recommended, especially in activities loading the foot, to bring the pronated foot posture closer to neutral.

OBJECTIVES

To examine the immediate effect of medial heel wedge on static balance and load distribution in patients with increased pronation in the foot.

STUDY DESIGN

Experimental study design.

METHODS

Forty people with right dominant lower extremity participated in the study. For static balance assessment, we assessed ellipse surface, sway length, x-y mean, AP index, and Romberg ratio on 1 foot and measured load distribution as right-left foot and fore-hind foot with and without wedge.

RESULTS

There was a difference between the parameters of the ellipse surface and the Romberg ratio on the left side in the measurements performed with and without wedge for static balance on the left side ( P < 0.05) while there was no difference in the remaining values ( P > 0.05). In the load distribution, the change in the right anteroposterior foot was significant, increasing the load on the forefoot with the wedge ( P < 0.05) while we observed no difference in the left fore-hind foot load distribution and right-left foot load distribution ( P > 0.05).

CONCLUSION

Our study showed that for static balance, medial wedge can improve balance on the left side by decreasing sway, and for load distribution, the medial wedge changed the load distribution from back to front on the right side. These small differences in young healthy individuals are a preliminary indication that further studies are needed.

Efficacy of unloader knee orthosis and lateral wedge insole on static balance in medial knee osteoarthritis

Background

Medial knee osteoarthritis can contribute to pain and stiffness, interfere with balance and limit functional activities of daily living. Unloader knee orthosis or lateral wedged insoles are current conservative approaches used to treat these conditions. The aim of this study was to identify and compare the effects of them on the balance parameters.

Methods

66 subjects with mild to moderate medial knee osteoarthritis were randomly assigned to wear unloader knee brace or full-length 6° lateral wedge insole. Primary outcome balance parameters were stability %, path length and average velocity of center of pressure and mobility score which were investigated by HUMAC® Balance and Tilt system. Secondary outcome measures were knee function score using Knee Injury and Osteoarthritis Outcome Score scale. Assessment was performed at baseline and six months post orthotic intervention period.

Findings

Both orthoses improved all parameters compared to the baseline condition (p < 0.05). Unloader knee orthosis showed a significant improvement in all balance parameters compared to lateral wedged insoles (p < 0.001) except mobility scores (p = 0.527). Except activities of daily living (p = 0.752) and sports and recreational activities (p = 0.437), unloader knee orthosis had a greater effect on the pain (p = 0.002) and symptoms (p < 0.001) sub scales than lateral wedged insoles. However, quality of life sub-scale scores for insoles were more effective than the knee orthosis.

Interpretation

Unloader knee orthosis improved balance and knee function scores more than lateral wedged insole, though both orthoses produced significantly improved results compared to baseline assessment.

A 120-second stretch improves postural control and plantar pressure: quasi-experimental study

BACKGROUND

There are no studies on long-term bilateral calf stretching in relation to balance and plantar pressure.

OBJECTIVES

To demonstrate that there is better control of posture and pressures after continuous stretching of the posterior calf muscles.

DESIGN AND SETTING

Pre and post-intervention study conducted in a private clinic.

METHODS

We measured static footprints and stabilometry before and after continuous passive plantar flexor stretching of duration 120 seconds, among 24 healthy subjects.

RESULTS

We found differences in Y displacement with eyes closed (P = 0.010), but not among other variables with eyes closed: X displacement (P = 0.263); surface (P = 0.940); laterolateral speed displacement (P = 0.279); and anteroposterior speed displacement (P = 0.914). There were also no differences in eyes-open variables: X displacement (P = 0.341); Y displacement (P = 0.491); surface (P = 0.167); laterolateral speed displacement (P = 0.852); and anteroposterior speed displacement (P = 0.079). The plantar pressures in the heel (maximum pressure, P = 0.048; mean pressure, P = 0.001) and in the midfoot (maximum pressure, P = 0.004; mean pressure, P = 0.004) were reduced, but not in the forefoot (maximum pressure, P = 0.391; mean pressure, P = 0.225). The surface became larger in the forefoot (P = 0.000) and midfoot (P = 0.021).

CONCLUSIONS

Continuous static stretching of plantar flexors for 120 seconds improved stance balance and reduced plantar pressures (maximum and mean) in the rearfoot and midfoot. It also increased the surface in the midfoot and forefoot.

TRIAL REGISTRATION

at clinicaltrials.gov, under the number NTC03743168.

Effectiveness of Custom Foot Insoles to Decrease Plantar Pressure: A Cross-over Randomized Trial Study

Background: Harderness insoles decrease plantar pressure and reduce the foot injury incidence in sport. The purpose of our study was to analyze the plantar pressure variation in moto riders after riding in a real speed circuit with a custom foot 52⁰ Shore EVA insole. Methods: A crossover randomized trial study was performed (consent no. #050520165316). Riders were assessed by an expert motorsport senior podiatry. The participants’ mean age was 35 ± 3.29. Participants completed a 20 min training riding with their own motorcycle in a real speed circuit. Plantar pressures were registered with a baropodometric platform evaluating an Ethyl Vinyl Acetate custom foot insole (CFI) manufactured with 3 mm thickness and 52° Shore A hardness. The Plantar pressures were registered before riding, after riding without EVA insole, and after riding with EVA insole. Results: Total Plantar pressures in right and left foot, and total surface area decrease after riding with EVA insoles. Conclusion: The use of an EVA insole with 52⁰ shore A hardness riding on a motorcycle in speed circuit decreased the total plantar pressures and surface areas values.

A shoe-insole to improve ankle joint mechanics for injury prevention among older adults

Technologies to assist senior individuals with active walking are important. This experiment aimed to investigate whether a customised insole geometry would reduce the risk of falls and locomotive injuries. The tested insole incorporated a built-in inclination to assist ankle dorsiflexion (2.2°) and eversion (4.5°). Twenty-six older adults and 30 younger counterparts undertook gait assessment with and without the experimental insole while 3 D motion capture and force plates recorded gait. The insole increased swing foot-ground clearance, with.43 cm for the older adults' dominant foot. The insole also prevented excessive lateral centre of pressure movement. The main insole effects on foot contact mechanics were (i) prolonged time to foot-flat (.015 s) and (ii) improved energy efficiency (2%). Reduced knee adduction moment (>15%) was observed in the older group. Shoe insoles to provide dorsiflexion and eversion support may have the potential to reduce the risk of falls and locomotion-related injuries for older adults.Practitioner Summary: Using 3 D gait assessment techniques this research investigated shoe-insoles incorporating ankle dorsiflexion and eversion support features. It was shown that falls risk and locomotive injuries could be reduced by the application of orthotics to support ankle dorsiflexion and eversion. Shoe-orthotics may provide practical low-cost solutions to correcting gait impairments.Abbreviations: MFC: minimum foot clearance; CoP: centre of pressure; OA: osteoarthritis; GRF: ground reaction forces; IREDS: infra-red light emitting diodes; PE: potential energy; KE: kinetic energy; IQR: interquartile range; ANOVA: analysis of variance.

Orthoses versus gait retraining: Immediate response in improving physical performance measures in healthy and medial knee osteoarthritic adults

The conservative techniques of treating knee osteoarthritis (kOA) include wearing orthoses such as knee braces and laterally wedged insoles and applying gait modification techniques such as toe-in gait and toe-out gait. This study aimed at assessing the immediate effects of these techniques in improving physical function of healthy and kOA participants. Five Osteoarthritis Research Society International (OARSI) recommended performance-based tests were randomly applied to measure physical function: (1) 30-second chair stand test (30CST), (2) 40-m (4 × 10) fast-paced walk test (40FPW), (3) stair climb test (SCT), (4) timed up and go test (TUGT) and (5) 6-minute walk test (6MWT) during a single-visit on 20 healthy and 20 kOA patients (age: 59.5 ± 7.33 and 61.5 ± 8.63 years, BMI: 69.95 ± 9.86 and 70.45 ± 8.80 kg/m²). The interventions included natural gait, toe-out gait, toe-in gait, laterally wedged insoles and knee brace. Analysis was performed through repeated-measures ANOVA and independent sample t-test. 30CST and TUGT showed no significant differences for the five test conditions (p > 0.05). Toe-out showed profound effects via pairwise comparison in impairing the physical function while knee brace improved it during 40FPW, SCT and 6MWT. In general, all the tested conservative techniques except laterally wedged insoles had immediate effects on physical performance measures in both healthy and medial knee osteoarthritis participants. The valgus knee brace improved the parameters the most, while toe-out gait impaired them the most. Future studies can develop strategies for improving gait retraining methods on the basis of issues identified by this study.

Pressure and Traction Technique Improves Postural Control More Than Tactile Stimulation in Foot Plantar Fascia: A Randomized Single-Blind Trial

OBJECTIVE

To check the acute effects of manual pressure and traction technique on balance and plantar footprint variables.

DESIGN

A single-blind clinical study with 2 groups.

SETTING

Private practice.

PARTICIPANTS

Healthy participants (N=40; 28 female and 12 male) were recruited to carry out a single-blind study.

INTERVENTIONS

Experimental group performed a bilateral plantar fascia manual pressure and traction technique. Control group performed a tactile stimulation. The position of the participant, the therapist, and the time of application of the techniques (5min) were the same for both interventions.

MAIN OUTCOME MEASURES

We measured stabilometry variables and static footprint. The footprint variables were divided in rear, middle, and front foot areas.

RESULTS

Significant differences were found in stabilometry variables. There was an improvement in experimental group at X displacement with eyes open (P=.014) and surface eyes closed (P=.046) variables.

CONCLUSIONS

After technique the experimental group improved the stabilometry variables, specifically surface with eyes closed and X displacement with eyes open. The static footprint variables have not shown differences after the technique compared with the control group.

Acute effects of myofascial induction technique in plantar fascia complex in patients with myofascial pain syndrome on postural sway and plantar pressures: A quasi-experimental study

OBJECTIVES

The prevalence of myofascial pain syndrome varies from 21% 93%. Several studies have shown that myofascial induction is effective in treating myofascial pain syndrome. Although these techniques have shown some effectiveness in clinical practice, there have been little study into their effects, and have deep effects. The purpose of this study was to investigate if the application of a single myofascial induction technique for each foot, targeted to the plantar fascia resulted in changes in balance and footprint variables.

DESIGN

A quasi-experimental study.

SETTING

An outpatient clinic.

SUBJECTS

20 healthy participants (12 females and 8 males) were evaluated pre and post Myofascial induction technique for each foot in plantar fascia during 5 min.

METHODS

We measured static footprint and stabilometry variables in asymptomatic subjects. The footprint surface area was divided: bilateral rear foot, bilateral midfoot, bilateral fore foot.

RESULTS

We found differences in the footprint variables: maximun pressure in forefoot (p = 0.025), surface in forefoot (p = 0.03). The myofascial induction has no effects on stabilometry variables.

CONCLUSIONS

The immediate effects of the longitudinal technique of myofascial induction of the plantar fascia are the increase of surface and maximum pressure in fore foot.

Immediate Effects of Intermittent Bilateral Ankle Plantar Flexors Static Stretching on Balance and Plantar Pressures

OBJECTIVE

The purpose of this study was to analyze the immediate effects of an intermittent plantar flexion static-stretching protocol on balance and plantar pressures.

METHODS

The study included a sample size of 24 healthy participants (21 female and 3 male). Participants were 32.20 ± 8.08 years, 166.20 ± 8.43 cm, and 62.77 ± 9.52 kg. All participants performed an intermittent plantar flexion static-stretching protocol. Five sets (60 seconds intermittent stretch; 15 seconds for the rest time) of a passive plantar flexor stretching (70% to 90% of the point of discomfort) were performed. Static footprint analysis and a stabilometry analysis were performed before and after stretching. A P value < .05 with a CI of 95% was considered statistically significant for all tests.

RESULTS

Intermittent ankle plantar static stretching resulted in a significantly greater forefoot surface contact area and lower rear foot medium and maximum plantar pressures. In addition, static stretching caused a lower displacement of the center of pressure for both eyes open and eyes closed conditions.

CONCLUSION

An intermittent plantar flexor static-stretching protocol improved balance and reduced rear foot plantar pressures (maximum and medium pressures).

Effects of Ankle Angular Position and Standing Surface on Postural Control of Upright Stance

The purpose of the study was to investigate the effects of ankle angular position and standing surface type on static upright balance. Ten young adults stood on a force platform or on a firm wedge that induced 15° of either dorsiflexion or plantarflexion. In addition, a piece of foam was placed on top of the force platform and on the wedge. The center of pressure distance and velocity in the anteroposterior and mediolateral directions were calculated. Significantly larger magnitudes in most of the investigated variables were seen while standing with ankles in the dorsiflexion when compared with standing with the ankle joints in a natural position (p < .05). Plantarflexion increased the center of pressure anteroposterior velocity by 87% when compared with a natural stance (p < .05). Standing on the foam surfaces resulted in increases in all of the center of pressure measures by an average of 38% in all of the ankle conditions.

The effectiveness of rearfoot medial wedge intervention on balance for athletes with chronic ankle instability

BACKGROUND

Athletes with chronic ankle instability (CAI) often develop complications such as pain, instability, and reduced postural control and balance stability, all of which affect athletic performance. This study investigated the effects of a 4° medal wedge intervention on static and dynamic balance in athletes with CAI.

METHODS

The participants were 24 healthy and 25 CAI athletes. Participants received a 4° medial wedge applied at the rear foot insole and completed the experiment measurements before and after the wedge intervention. The main outcome measures included the area and path length of the center of pressure when participants performed single-leg standing balance in the closed eye condition and the dynamic balance scores of a multiple single-leg hop stabilization test.

RESULTS

The single-leg standing balance significantly improved in CAI (P = .027) and control groups (P = .005) after the medial wedge intervention. The dynamic balance scores significantly decreased from 53.00 ± 25.22 to 41.24 ± 21 48 (P = .015) in CAI group after medial wedge intervention.

CONCLUSION

Wearing a 4° medial wedge applied at the rear foot insole improved static and dynamic balance immediately in athletes with CAI. We suggest that clinicians may provide the foot insole to improve balance deficit in athletes having CAI.

Acute Effects of Intermittent Versus Continuous Bilateral Ankle Plantar Flexor Static Stretching on Postural Sway and Plantar Pressures: A Randomized Clinical Trial

BACKGROUND

Postural balance and fall efficacy (self-perceived confidence in performing daily physical activities) have been found to be risk factors associated with falls in older adults. Stretching is one intervention that has been investigated to improve balance and therefore reduce fall risk. Various forms of stretching have been evaluated with different outcomes, but there is a lack of knowledge about the effect of stretching (continuous and intermittent) on plantar pressures and balance. Therefore, the aim of the present study was to analyze the effects of stretching (continuous and intermittent) of the bilateral ankle plantar flexors on plantar pressures and static balance.

METHODS

A randomized clinical trial was carried out. Forty-eight healthy subjects (42 females and 6 males) were recruited in an outpatient clinic. Subjects were randomly assigned to an intermittent stretching group (five sets of 1 min; 15 s of rest) or a continuous stretching group (2 min of continuous stretching) of the plantar flexors. Plantar pressures and balance using stabilometry were measured before and after stretching.

RESULTS

There were significant differences between intermittent and continuous stretching in rearfoot maximum pressure, forefoot surface area, and center of pressure surface area with eyes open.

CONCLUSIONS

Bilateral intermittent stretching of the ankle plantar flexors was found to be more effective than continuous stretching for the reduction of rearfoot maximum pressure and improved balance.

Standing on wedges modifies side-specific postural control in the presence of lateral external perturbations

Standing on wedges changes the position in the ankle joints and affects postural stability in the medial-lateral direction. The objective of the study was to investigate the role of wedges and external lateral perturbations on anticipatory (APA) and compensatory postural adjustments (CPA). Ten healthy young participants were exposed to perturbations applied to the lateral part of their right shoulder when standing on a planar surface, on a medial or lateral wedges. Bilateral electromyographic activity of dorsal and ventral postural muscles and the center of pressure (COP) displacement were recorded and analyzed during the APA and CPA phases. When exposed to the lateral perturbation, reciprocal activation of shank muscles was seen on the side of the perturbation while co-contraction of shank muscles was seen on the contralateral side during the APA and CPA phases. Standing on a wedge was associated with decreased magnitudes of co-contraction and reciprocal activation of shank muscles. The COP displacements were smaller in the APA phase and larger in the CPA phase while standing on wedges compared to standing on the planar surface. The outcome of the study provides a basis for future investigations of incorporating wedges in balance re-training paradigms for the elderly or individuals with neurological impairment.

Comparison between Decision Tree and Genetic Programming to distinguish healthy from stroke postural sway patterns

Maintaining balance is a motor task of crucial importance for humans to perform their daily activities safely and independently. Studies in the field of Artificial Intelligence have considered different classification methods in order to distinguish healthy subjects from patients with certain motor disorders based on their postural strategies during the balance control. The main purpose of this paper is to compare the performance between Decision Tree (DT) and Genetic Programming (GP) - both classification methods of easy interpretation by health professionals - to distinguish postural sway patterns produced by healthy and stroke individuals based on 16 widely used posturographic variables. For this purpose, we used a posturographic dataset of time-series of center-of-pressure displacements derived from 19 stroke patients and 19 healthy matched subjects in three quiet standing tasks of balance control. Then, DT and GP models were trained and tested under two different experiments where accuracy, sensitivity and specificity were adopted as performance metrics. The DT method has performed statistically significant (P < 0.05) better in both cases, showing for example an accuracy of 72.8% against 69.2% from GP in the second experiment of this paper.

Learning Upright Standing on a Multiaxial Balance Board

Upright stance on a balance board is a skill requiring complex rearrangement of the postural control. Despite the large use of these boards in training the standing posture, a comprehensive analysis of the learning process underlying the control of these devices is lacking. In this paper learning to maintain a stable stance on a multiaxial oscillating board was studied by analyzing performance changes over short and long periods. Healthy participants were asked to keep the board orientation as horizontal as possible for 20 sec, performing two sessions of 8 trials separated by 15-min pause. Memory consolidation was tested one week later. Amplitude and variability of the oscillations around horizontal plane and area and sway path of the board displacement decreased rapidly over the first session. The performance was stable during the second session, and retained after 1 week. A similar behavior was observed in the anterior-posterior and medial-lateral directions for amplitude and variability parameters, with less stable balance in the anterior-posterior direction. Approximate entropy and mean power frequency, assessing temporal dynamics and frequency content of oscillations, changed only in the anterior-posterior direction during the retention test. Overall, the ability to stand on a balance board is rapidly acquired, and retained for long time. The asymmetric stability between anterior-posterior and medial-lateral directions replicates a structure observed in other standing stances, suggesting a possible transfer from previous postural experiences. Conversely, changes in the temporal dynamics and the frequency content could be associated with new postural strategies developed later during memory consolidation.