The effects of unilateral medial arch support stimulation on plantar pressure and center of pressure adjustment in young gymnasts

An evaluation of a bespoke modified UCBL foot orthosis on subjects with flat foot using kinetic measurements and user comfort scores: A randomized controlled trial

AIM

The purpose of this study was to assess and evaluate the effect of a bespoke Modified UCBL Foot Orthosis (MUFO) using both kinetic parameters (Centre of Pressure (CoP) and the Ground Reaction Force (GRF) pattern) and comfort scores in subjects diagnosed with flat foot.

METHOD

This study included thirty-four young adults with symptomatic flatfeet. Two Kistler force plates (100 Hz) were used to record the CoP sway and GRF pattern during four conditions; 1) an MUFO and standard-fit shoe; 2) the University of California-Berkley Lab (UCBL) insole and standard-fit shoe; 3) barefoot and 4) standard-fit shoe only. The magnitude of subject comfort with UCBL and MUFO also was measured by a 10 cm Visual Analogue Scale (VAS) during walking.

RESULTS

The MUFO decreased mean lateral displacement in the initial phase and midstance of gait compared to barefoot walking. During the propulsion phase use of the new MUFO produced more lateral excursion with a mean difference of 3 mm) P < 0.001(compared to barefoot walking and standard shoe wear. No significant difference in comfort rate was found between the MUFO and UCBL (P = 0.165).

CONCLUSION

The MUFO produced effective pronation control and decreased the CoP displacement in all of stance phase.

Horizontal Heterophoria Modifications by Means of Thin Proprioceptive Stimulations Applied on the Foot Sole: A Randomised Study

Some authors have demonstrated that proprioceptive stimuli applied on the feet soles can interfere on the ocular muscles. However, these studies do not clarify possible functional differences between the dominant eye and the non-dominant eye. The purpose of this randomised study is to establish if the positioning of an Internal Heel Wedge (IHW) and an External Heel Wedge (EHW) can modify horizontal heterophoria, determine dissimilar behaviours between the dominant eye and the non-dominant eye. Forty-two healthy subjects, with a right dominant eye, were tested. The 1.5 mm-thick proprioceptive stimuli were shaped out of a cork half-moon. The experimental group was divided into two groups: IHW group and EHW group. Both groups performed the "Baseline" (without mechanical stimulation) and "After 15'" (following a fitting period of 15 minutes on a treadmill with mechanical stimulation) trials. The control group performed the same trials without any podalic stimulation. Meaningful changes were observed on the horizontal heterophoria of the non-dominating eye with an IHW. Non-statistically significant variations were observed with an EHW and in the Control group. A thin heel wedge applied on the foot sole was able to generate functional changes in the non-dominant eye and could help health professionals develop increasingly personalised rehabilitation programmes.

Arch-Support Induced Changes in Foot-Ankle Coordination in Young Males with Flatfoot during Unplanned Gait Termination

Objective: The efficacy of arch orthoses in posture adjustment and joint coordination improvement during steady-state gait is well documented; however, the biomechanical changes of gait sub-tasks caused by arch support (AS), especially during gait termination, are poorly understood. Hence, this study aimed to investigate how the acute arch-supporting intervention affects foot–ankle coordination and coordination variability (CV) in individuals with flatfoot during unplanned gait termination (UGT). Methods: Twenty-five male patients with flatfoot were selected as subjects participated in this AS manipulation study. A motion capture system was used for the collection of the metatarsophalangeal joint (MPJ) and ankle kinematics during UGT. MPJ-Ankle coordination and CV were quantified using an optimized vector coding technique during the three sub-phases of UGT. A paired-sample t-test from the one-dimensional statistical parametric mapping of one-dimensional was applied to examine the data significance. Results: Significant differences for the joint kinematics between non-arch-support (NAS) and AS were exhibited only in the MPJ transverse plane during the middle and later periods of UGT (p = 0.04–0.026). Frontal plane MPJ-ankle coordination under AS during stimulus delay significantly decreased from 177.16 ± 27.41° to 157.75 ± 32.54° compared with under NAS (p = 0.026); however, the coordination pattern had not changed. Moreover, no significant difference was found in the coupling angle variability between NAS and AS in three planes during sub-phases of UGT (all p > 0.5). Conclusions: The detailed intrinsic characteristic of AS induced acute changes in lower extremity segment coordination in patients with mild flatfoot has been recorded. This dataset on foot-ankle coordination characteristics during UGT is essential for explaining foot function and injury prediction concerning AS manipulation. Further studies are expected to reflect lower limb inter-joint coordination during gait termination through the long-term effects of AS orthoses.

Differences in stabilometric correlates of pain relief after wearing postural insoles for six weeks between chronic nociceptive and neuropathic foot pain. An open-label pilot study

OBJECTIVE

The aim of this study was to determine if the use of postural insoles could result in a noticeable reduction in the foot pain intensity in patients with a chronic pain condition, either nociceptive (ankylosing spondylitis, AS) or neuropathic (small fiber neuropathy, SFN).

METHOD

In this open-label pilot study, patients were asked to wear postural insoles for a continuous period of 6 weeks. The primary endpoint was the mean daily pain intensity at foot mobilization measured using a visual analogue scale (VAS). The secondary endpoints included global pain intensity scores (at rest or under mobilization), clinical questionnaires on pain and daily functioning (including the Brief Pain Inventory (BPI), the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Neuropathic Pain Symptom Inventory (NPSI) and the DN4 questionnaire), and posturo-podiatric variables assessed on clinical examination or using a baro-stabilometric platform.

RESULTS

The study was completed by 17 patients with AS and 12 patients with SFN. After wearing postural insoles for 6 weeks, a significant improvement was observed on the primary endpoint (decrease in VAS pain score at the foot during mobilization) in both groups of patients (from 6.4 ± 2.4 to 3.6 ± 2.6 (p = 0.0004) in the AS group and from 5.7 ± 2.2 to 2.4 ± 1.6 (p = 0.0003) in the SFN group). Improvement was also observed for all other pain and activity scores (global pain at rest or during mobilization (VAS), BDI, and BASDAI for the AS group or NPSI and DN4 for the SFN group), as well as for posturo-podiatric clinical variables. However, we did not find any difference in any clinical pain score whether the posturo-podiatric clinical outcomes were positive or not. Regarding the stabilometric measures, the only significant change after the intervention was a reduced mean velocity of center of pressure displacement in the AS group only (mVel in mm/s: from 7.4 ± 2.0 vs. 6.7 ± 1.9, p = 0.017). In addition, the reduction in mVel correlated to that of the BPI score (r = 0.48, p = 0.0496).

CONCLUSION

In both groups of patients, wearing postural insoles for 6 weeks led to a significant decrease in local pain intensity at foot level and to more global analgesic effects and positive posturo-podiatric changes. However, these latter changes did not appear to be strongly associated with pain relief. Nevertheless, an index of a better postural control, i.e. mVel decrease, was found to be related to a reduction of pain interference in daily life activities in AS patients, but not in SFN patients. Therefore, in the context of neuropathic pain, mechanisms other than postural changes likely contribute to the analgesic effects of wearing postural insoles, in contrast to nociceptive pain due to spinal osteoarthritis.

The effect of age, sex and a firm-textured surface on postural control

In previous studies, the influence of plantar sensation has been examined using various textured surfaces with different stiffness materials to assess static balance. This study investigated the effects of a Firm Textured Surface (FTS) along with age and sex-related influences on postural control under different visual conditions. Forty subjects (20 elderly, 10 males, mean age 68.30, 10 females, mean age 68.00, and 20 young people, 10 males, mean age 25.45, 10 females, mean age 27.30) participated in this study maintained a quiet standing on FTS, foam and firm surfaces with eyes open and closed. The center of pressure displacement (CoP_DISP), CoP velocity (CoP_VEL), and sway velocity of the CoP in anteroposterior (AP) and mediolateral (ML) direction (V_A/P and V_M/L) were measured. FTS was associated with lower postural sway measures in both the groups with eyes open and closed. However, the foam surface showed the worst results in all postural parameters under all experimental conditions. Separate four-way ANOVAs were applied to each dependent variable. The main effects of surface (p < 0.0001), vision (p < 0.0001) and age (p < 0.0001 for CoP_DISP, CoP_VEL and V_A/P; p = 0.0003 for V_M/L) were significant in each of the four fitted models. Sex was never significant, either as a main effect or an interaction with other experimental factors. Eyes open were able to reduce the negative effects of the foam surfaces but without vision the proprioceptive sensory system cues of the body state become more important for maintaining balance. A good stimulation with rigid texture should be considered as relief to reduce the physiological-related decline of afferent information with age.

Proprioceptive effects on gait and postural stability through mechanical stimulation with an Internal and External Heel Wedge: An interventional single-arm study

BACKGROUND

Previous studies have shown that the stimulation of the foot sole can provide important information about the body's position and locomotion. However, these studies do not clarify how the position of the mechanical stimulation on the foot sole affects the gait cycle.

AIMS

This interventional single-arm study aims to verify if the insertion of an Internal Heel Wedge (IHW) and External Heel Wedge (EHW) can modify the stabilometric and podobarometric variables, the functional changes during the gait cycle, the different responses between the dominating lower limb and the non-dominating lower limb, and the potential temporal summations of the proprioceptive stimulation.

METHOD

Twenty-three healthy subjects (age 31 ± 5 years; weight 62 ± 1 kg; height 168±6 cm), with a right dominating lower limb, were recruited. The IHW and EHW were created out of half-moon-shaped cork pieces having a 1.5 mm thickness, 6 cm length and 3 cm height. The sequence of tests foresaw trials without IHW or EHW (Baseline), trials with IHW or EHW (Acute), trials after an adaptation period of 15 min on a treadmill with IHW or EHW (after 15').

RESULTS

Data showed statistically significant variations in the Step Rate, Duration of the cycle of the left step and Single Right Support phase for the IHW, Duration Single Right support and Single Left Support phase for the EHW.

CONCLUSION

Data showed that a thin proprioceptive stimulation of the plantar arch was enough to induce changes in the gait cycle and that, upon changing the position of the proprioceptive stimulation, the functional response of the feet was inverted. These results can help health professionals provide a correct interpretation of the clinical data during follow-ups, avoiding undesirable and harmful effects on the patients' recovery.

Effect of sensory stimulation applied under the great toe on postural ability in patients with fibromyalgia

Fibromyalgia (FM) is a chronic pain syndrome, characterised by several symptoms. One of the most prevalent symptoms in FM is balance impairment that compromise the autonomy, function and performance status of patients.Purpose: The main objective of the present study was to evaluate the effect of sensory stimulation provided by the use of a low additional thickness of 0.8 mm placed under the great toes bilaterally on the centre of pressure (CoP) measures in patients with FM. It was hypothesised that postural ability would change with a low focal additional thickness used to compute these measures.Materials and Method: Twenty-four patients with FM voluntarily participated in this study. Postural performance during quiet standing was investigated through the CoP displacements recorded using a force-plate. Sensory stimulation was provided by a small additional thickness of 0.8 mm placed under the great toe bilaterally and two conditions were compared: additional thickness 0 (control) and 0.8 mm.Results: An improvement of body balance through spatial parameters with sensory cutaneous stimulation applied under the great toe bilaterally were observed in patients with FM. Our results showed a significant decrease of surface area and mean speed of CoP, associated to a significant decrease of variance of speed. An additional observation is that sagittal (Y) mean position of the CoP gets more anterior (+ 5 mm) relative to control condition.Conclusion: These findings brings new clinical perspectives in the development of intervention strategies in the management of patients with FM and balance disorders, completing validated therapeutic strategies.

Postural Changes During Exteroceptive Thin Plantar Stimulation: The Effect of Prolonged Use and Different Plantar Localizations

Somatosensory information arising from the foot has an important role in posture as well as visual and vestibular cues. Our hypothesis is that the effects of prolonged stimulation are greater than those of short stimulation and that varying the plantar location can affect postural control. Forty healthy participants were recruited and randomly assigned to four different plantar location groups: Lateral Insert (LI), Medial Insert (MI), Disharmonious Insert (DI), and Central Insert (CI). An instrumental assessment was performed before the plantar stimulation (T0), immediately after the positioning of the inserts (T1), and after 7 days of daily stimulation (T7). A follow-up was performed 15 days after (T15). The following stabilometric parameters were considered for both open eyes (OE) and closed eyes (CE) conditions: length of the sway (L) of the Center of Pressure (CoP); CoP maximum movements in the medio-lateral (X), and antero-posterior directions (Y). Comparing the effects of different plantar insert locations, the MI and CI groups were significantly different in the follow-up measures at T15, specifically for closed eyes measures. When we compared measures across time within each location group, CI group increased measures of X and Y data at T7 compared to other assessment times (T0, T1, and T15). In both MI and LI groups, L was significantly reduced, and X significantly increased at the T7 assessment compared to the T0, T1, and T15 assessments. The prolonged use of exteroceptive plantar stimulation and the location of plantar inserts may have a role to reshape postural control.

The immediate effect of plantar stimulation on dynamic and static balance: A randomized controlled trial

OBJECTIVE

To examine the immediate effect on dynamic and static balance of a manual protocol of plantar stimulation in healthy subjects.

MATERIALS AND METHOD

Of the 144 healthy and physically active volunteers recruited, 98 subjects participated. Subjects were randomly assigned and allocated to the experimental group (EG) (n= 50), in which a 10-min manual protocol of plantar stimulation was applied on the right foot, or to the control group (CG) (n= 48). The change scores of the modified Star Excursion Balance Test (mSEBT) and the Unipedal Stance Test (UPST) were used to assess the immediate effect of the protocol on dynamic and static balance, respectively.

RESULTS

In the dynamic balance, a group effect was found in the anterior direction, posteromedial direction and composite scores of the mSEBT when groups were compared by limb. Changes in the posteromedial direction of both limbs (right limb: p= 0.002, left limb: p= 0.05) and composite score of the right limb (p= 0.009) were significantly greater in the EG versus the CG. Non-significant results were found in the static balance (UPST time).

CONCLUSIONS

The application of a 10-minute manual stimulation protocol without joint mobilization, addressed to stimulate the plantar cutaneous mechanoreceptors, could elicit benefits on dynamic balance. This improvement was observed bilaterally even though only one plantar surface was stimulated. As balance deficits may impair functional movements and regular training in sports, this intervention aims to ameliorate dynamic balancing ability could improve the functional recovery of sport gestures.

How can the stimulation of plantar cutaneous receptors improve postural control? Review and clinical commentary

Postural control requires constant and subconscious postural sway to manage balance and achieve postural stability. These movements of regulation are based in particular on cutaneous plantar information. The foot constitutes a functional whole that participates in the mechanisms of postural control and regulation. It represents the direct interface between the body and the ground during quiet standing, and plantar cutaneous information contributes to postural control. Upright balance mechanically depends on the gravitational torque produced by the forces of gravity and reaction of the ground. In this context, the foot behaves like a sensory system for postural regulation whose objective is to maintain a state of stability within a changing and constraining environment. There is a relation between balance improvement and the facilitation of sensory feedback related to the activation of the plantar cutaneous mechanoreceptors. From a clinical point of view, the application of additional tactile cues may have therapeutic benefits in relation to fall prevention, or to improve specific types of chronic pain.

Plantar cutaneous afferents influence the perception of Subjective Visual Vertical in quiet stance

The estimation of Subjective Visual Vertical (SVV) involves the allocentric, gravitational and egocentric references, which are built by visual, vestibular and somatosensory afferents. Our goals were to assess the influence of plantar cutaneous afferents on the perception of SVV, and to see if there is a difference according to the efficiency of plantar cutaneous afferents. We recruited 48 young and healthy subjects and assessed their SVV and postural performances in quiet stance with a force platform, at 40 or 200 cm, in four ground conditions: on firm ground, on foam, with a bilateral, or with a unilateral 3 mm arch support. We also assessed the efficiency of our subjects' plantar afferents with the plantar quotient method and divided them in two groups: subjects with a normal use of plantar afferents and subjects with Plantar Exteroceptive Inefficiency (PEI). The results showed significant decreases in the counter clockwise SVV deviation only with the unilateral arch support, at near distance, and among the typically behaving subjects. We conclude that asymmetric foot cutaneous afferents are able to bias the egocentric vertical reference and hence influence the perception of SVV. This influence disappears among subjects with PEI, probably because of a distortion of the plantar signal.

Do plantar hyperkeratoses affect balance in people older than 65 years old?

Tactile information picked up by plantar receptors provides afferent sensory information that is fundamental for controlling body balance. Plantar hyperkeratoses may alter the quality and quantity of such information, thereby modifying balance.

AIM

Analyse how plantar hyperkeratosis debridement affects static body balance in subjects of 65 years of age or older.

METHODS

In order to analyse the impact of hyperkeratoses on balance, 50 older people took part in this study. Pain caused by plantar hyperkeratoses was measured on a visual analogue scale. Static balance was assessed on a pressure sensitive platform. The treatment was scalpel debridement of hyperkeratoses.

RESULTS

Pain decreased significantly (p=0.03). Regarding the variables analysed, significant differences were found between pre- and post-treatment values in anteroposterior length (Length, mm) (p=0.032) and anteroposterior amplitude (Amp, mm) (p=0.044) of the centre of plantar pressure with eyes open.

CONCLUSIONS

Plantar hyperkeratosis debridement is capable of interfering favourably with sensory afferent inputs, thereby improving control of stability and modifying stabilometric readings in the AP component when a subject balance with eyes open.

Comparison of balance strategies in mountain climbers during real altitude exposure between 1.500m and 3.200m: Effects of age and expertise

PURPOSE

The aim of this study was to estimate the effect of altitude (1500m vs. 3200m) on balance strategies, and to determine the influence of age (> or <40 years) and expertise (> or <20days of mountain climbing/year) on postural stability at altitude.

METHOD

Eighty-nine volunteer mountaineers were tested at 1500m, 3200m immediately after exiting the cable car and at 3200m following the climb and return. Double-leg stance with eyes closed and single-leg stance with eyes open were tested. The center of pressure (CoP) was recorded for 12.8s using a stabilometric force platform. Length, surface, ratio (length/surface), and average speed of the CoP, as well as lower limb loading were calculated. Groups and altitudes were compared using ANOVA. Significance was set to p<0.05.

RESULTS

CoP ratio was significantly higher during both balance conditions at 3200m compared to 1500m (p<0.05). Lower limb loading was symmetrical at 1500m but not at 3200m (p<0.05). There was no influence of age or expertise at 1500m (p=NS), however at 3200m, older subjects and subjects with less expertise had greater length and surface of the CoP, showing more instability (p<0.05).

CONCLUSION

Postural stability was immediately reduced on arrival at 3200m, particularly in subjects above the age of 40 years with less expertise.

Controlling Posture and Vergence Eye Movements in Quiet Stance: Effects of Thin Plantar Inserts

The purpose of this study was to assess properties of vergence and saccade eye movements as well as posture in quiet stance, and the effects of thin plantar inserts upon postural and oculomotor control. The performances of 36 young healthy subjects were recorded by a force platform and an eye tracker in three testing conditions: without plantar stimulation, with a 3 millimetre-thick plantar insert, either a Medial or a Lateral Arch Support (MAS/LAS). The results showed a decrease of the Surface and Variance of Speed and a more posterior position of the CoP with either stimulation compared with the control condition. The fractal analysis showed a decrease with MAS. Wavelet analysis in the time-frequency domain revealed an increase in the Cancelling Time of the low frequency band with MAS. These results suggest a better stability for a lower energy cost. Concerning eye movements, the inserts influenced only vergence (not saccades): MAS caused an increase of the phasic amplitude of divergence, and conversely a decrease of the tonic amplitude. In contrast, LAS caused an increase of the tonic amplitude of convergence. Thus, MAS renders divergence less visually driven, while LAS renders convergence more visually driven. We conclude that the CNS uses the podal signal for both postural and vergence control via specific mechanisms. Plantar inserts have an influence upon posture and vergence movements in a different way according to the part of the foot sole being stimulated. These results can be useful to clinicians interested in foot or eye.

The efficacy of plantar stimulation on human balance control

AIM

The aim of this study was to evaluate the body sway using firm, foam, and firm textured surfaces on 17 young adults.

METHOD

Displacement of center of pressure (CoP), anteroposterior velocity (VA/P), and mediolateral velocity (VM/L) were measured.

DATA

The data showed a significant decrease of CoP, VA/P, and VM/L between support surfaces and vision.

RESULTS

The results showed that, differently from the firm and foam, the textured surface is able to increase the plantar feedback to maintaining postural control.

The efficacy of foot orthoses on alteration to center of pressure displacement in subjects with flat and normal feet: a literature review

PURPOSE

The aim of this review was to evaluate and compare the effect of foot orthoses on center of pressure (CoP) displacement in healthy patients and those with flat foot.

METHOD

The search strategy was based on the Population Intervention Comparison Outcome (PICO) method. A search was performed in PubMed, Science Direct, Google scholar and ISI web of knowledge databases by using selected keywords. Seventeen articles were selected for final evaluation. The procedure was followed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method.

RESULT

The results of the literature review demonstrated that there is lack of evidence to show that FOs improve CoP displacement in subjects with flat foot.

CONCLUSION

There is no consistent evidence to prove the efficacy of FOs on altering CoP displacement in healthy subjects but in those with flat foot, FOs decreased CoP excursion. Implications for Rehabilitation Foot orthoses (FOs) have become an integral part of the treatment of injuries of the foot, ankle, and lower extremity. Assessment of FOs effect on the COP displacement can help to provide a better understanding of the body's compensatory mechanisms and their therapeutic effects. There is no consistent evidence to prove the efficacy of FOs on CoP displacement in healthy subjects but in flat foot subjects foot orthoses decreased CoP excursion has been demonstrated.