Long distance running increases plantar pressures beneath the metatarsal heads: a barefoot walking investigation of 200 marathon runners

BACKGROUND: The growing popularity of endurance sports activities is associated with a growing number of metatarsal stress fractures in recreational runners. Excessive foot loading has been suggested as a potential cause for these problems [Bennell, K, Matheson G, Meeuwisse W, Brukner P. Risk factors for stress fractures. Sports Med 1999;28(2):91-122]. Therefore, the question arises whether long distance running affects foot loading characteristics like ground reaction forces and peak pressure in specific areas of the foot. PURPOSE: To investigate the effects of long distance running on plantar pressure patterns before and after a marathon race. STUDY DESIGN: Repeated measurements of recreational runners before and after a marathon race. METHODS: Two hundred participants of the third Muenster marathon, 2004, were measured before and after the race with plantar pressure measurements during barefoot walking on a capacitive platform. The ratio between forefoot and toe loading was calculated to assess a suggested loading shift between these areas. RESULTS: The results of the whole group of participants revealed a significant difference in foot loading characteristics before and after the race. Post-race peak pressure and impulse values were higher in the forefoot regions and reduced under the toes. CONCLUSIONS: The increased peak pressure under the metatarsal heads after the race indicates a load shift from the toes to the metatarsal heads. This suggests an increased loading of the metatarsal bones and could explain the increased incidence of metatarsal stress fractures in long distance runners.     

Clinical determinants of plantar forces and pressures during walking in older people

The aim of this study was to determine the extent to which clinical tests of structural characteristics of the foot and ankle could account for variation in the magnitude of regional forces and pressures under the foot during walking in older people. Plantar forces and pressures were obtained from 172 older people (53 men, 119 women) aged 62-96 years (mean 80.0, S.D. 6.4) using a floor-mounted resistive sensor mat system. Subjects also completed tests of foot posture, range of motion, strength, sensation and toe deformity. Multiple regression analysis was then used to determine which clinical variables were most strongly correlated with plantar forces and pressures. Maximum forces and peak pressures under most regions of the foot were largely explained by differences in bodyweight, with some important exceptions. Loading under the midfoot was associated with the arch index, loading under the first metatarsophalangeal joint (1st MPJ) was associated with 1st MPJ range of motion, and loading under the hallux was associated with hallux plantarflexor strength, 1st MPJ range of motion and the degree of hallux valgus deformity. Clinical measurements accounted for 13-53% of the variance in maximum force and 4-40% of the variance in peak pressures. These findings indicate that structural foot and ankle characteristics identified from clinical measurements can explain some key aspects of plantar loading patterns of the foot. This information provides further insights into the dynamic function of the foot, which might assist in the development of interventions for pressure-related foot complaints in older people.     

Regional plantar pressure during walking, stair ascent and descent

Regional plantar pressures during stair walking may be injurious in at risk populations. However, limited data are available examining the reliability of plantar pressure data collected during stair walking. The aims of this study were three fold; to assess the reliability of the plantar pressure data recorded during stair walking, to assess the effects of level ground and stair walking on plantar loading, and to develop regression equations to predict regional plantar pressures in stair walking from those collected on level ground. Fifteen subjects without conditions affecting their ability to walk on level surfaces or stairs were recruited. Each participant performed at least 10 steps in level ground and stair walking while plantar pressure data were recorded in six foot regions. Reliability was assessed using Intraclass Correlation Coefficient. A repeated measures ANOVA was used to assess the effect of activity on plantar pressure, and a linear regression was used to predict forefoot loading during stair walking. A reliability of 0.9 was achieved within 10 steps in all foot regions, with the forefoot requiring fewer steps. Plantar pressures were influenced by both, foot region and activity, with the heel and forefoot regions generally experiencing lower peak pressures and maximal forces during stair walking than level ground walking. The regression equations predicting peak pressure during stair walking accounted for between 37% and 70% of the variance of the stair walking data. These findings establish the reliability of plantar pressure data collected during stair walking. Future studies should investigate these parameters in clinical populations.     

Gait asymmetry in patients with limb length discrepancy

Foot loading patterns and neuromuscular function of both limbs during walking were investigated on 25 patients with limb length discrepancy. Plantar pressures and 2-D ground reaction forces were recorded simultaneously with electromyographic activities at two different walking speeds. Bilateral comparison indicated that moderate limb length discrepancies resulted in asymmetrical gait patterns. The duration of the stance phase was reduced in the short limb in both walking speeds. The vertical ground reaction force (F) in the push-off phase was greater in the long limb both at normal (1.33 (SO, 0.05 BW) vs. 1.29 (SD, 0.09 BW)) (P=0.0027) and fast walking speed (1.55 (SD, 0.11) vs. 1.48 (SD, 0.15 BW)) (P=0.001). Peak plantar pressures were higher under the big toe in the long leg and the heel-off occurred faster. The push-off phase was initiated earlier in the short leg. The maximum isometric torque of the long limb was considerably greater (673 Nm vs. 239 Nm) (P=0.026). The results imply that the loading of the long limb is greater and the foot loading patterns shifted more to the forefoot in the long, limb to compensate walking disturbances caused by limb length discrepancies.     

Simultaneous measurement of plantar pressure and shear forces in diabetic individuals.

Plantar foot ulceration is a diabetic complication whose underlying causative factors are still not fully understood. The goal of the current work was to simultaneously record plantar pressure and shear and examine the interrelationship of these forces; specifically, if peak shear and pressure occurred at the same site/time and whether adjacent shear forces had a greater tendency to be directed towards or away from each other. A custom built 16 transducer array was used to record forefoot shear and pressure during gait initiation in a cohort of 12 neuropathic diabetic individuals. The individuals were barefoot and the transducers were covered with a 5 mm thick layer of Minorplast. The greatest pressure occurred in the medial metatarsal heads (189 kPa) and the greatest shear in the lateral metatarsal heads (33 kPa). The interaction of the shear forces revealed that the plantar tissue was stretched to a greater magnitude than it was bunched (24 kPa vs 12 kPa, averaged over all regions). Normal distributions were determined for stretching and bunching in both the medial-lateral and anterior-posterior directions. When shear and pressure were considered in combination, half of the neuropathic individuals had peak shear and pressure occurring at the same site. These peak stresses did not occur at the same time (average difference of 0.186 s). The results of this study help to further characterize tissue stresses experienced on the plantar surface of the foot during gait initiation in neuropathic diabetic individuals.     

Pressure characteristics in painful pes cavus feet resulting from Charcot-Marie-Tooth disease

Charcot–Marie–Tooth (CMT) disease often presents with peripheral muscle imbalance associated with a painful cavus (medial high-arched) foot deformity which becomes increasingly severe and rigid as the disease progresses. The purpose of this study was to investigate the effect of pes cavus on foot pain and dynamic plantar pressure in CMT, and to explore the relationships between plantar pressure and pain. Sixteen participants diagnosed with CMT and painful pes cavus were assessed for foot posture, ankle dorsiflexion range of motion, levels of foot pain, functional impairment, health-related quality of life and plantar pressure distribution while walking. Plantar pressure parameters (mean pressure, peak pressure, pressure–time integral) and contact duration were measured using the Novel Pedar^® in-shoe capacitance transducer system and the foot was divided into rearfoot, midfoot and forefoot regions for analysis. Increasing cavus foot deformity was associated with more widespread foot pain and increased pressure under the forefoot and midfoot regions. In contrast, peak pressure decreased under the rearfoot. Neither relationship was found between foot pain intensity and any of the pressure variables, nor was ankle dorsiflexion range of motion correlated with pain location, intensity or degree of pes cavus. Although pes cavus in CMT is associated with substantial pain and dysfunction, there is no clear link between foot pain and plantar pressure. The more severe the degree of pes cavus, however, the more pressure develops under the lateral margin of the foot; probably as a result of the changed foot–ground contact seen during gait.     

A functional foot type classification with cluster analysis based on plantar pressure distribution during jogging

The purpose of this study was to establish a reference dataset for peak pressures and pressure-time integrals during jogging, to compare this reference dataset with existing walking data and to develop a foot type classification, all based on plantar pressure data obtained from 215 healthy young adults. The subjects ran at 3.3 m s(-1) over a 16.5 m long running track, with a built-in pressure platform mounted on top of a force platform. Peak pressures, regional impulses and relative regional impulses were measured. These variables were found to be reliable (all intra class correlation coefficients above 0.75) and, except for the heel areas, gender and asymmetry effects could be neglected. Highest peak pressures were found under the heel due to large impact forces during initial contact phase (ICP). In the forefoot, the highest peak pressure was found under the second metatarsal (64.2 +/- 21.1 N cm(-2)). Compared to walking data, overall higher peak pressures and impulses and difference in hallux loading were found during barefoot jogging. Four pressure loading patterns were identified using a K-means cluster analysis, based on the relative regional impulses underneath the forefoot: medial M1 pattern, medial M2 pattern, central pattern and central-lateral pattern. These four pressure loading patterns could help in the functional interpretation of the foot behaviour during the stance phase in slow running.     

A biomechanical assessment of the acute hallux abduction manipulation intervention

BackgroundNaturally aligned toes, particularly hallux, have reported with gripping functions during locomotion, thus expanding the forefoot loading area.Research questionThe purpose of this study was aimed to investigate the influence of hallux abduction manipulation on the foot plantar pressure distribution and inter-segment kinematic alterations.MethodsThirteen subjects participated in this toe manipulation study. A Footscan® pressure plate and Vicon motion capture system were utilized for the measurement of plantar pressure distribution and lower extremity and foot inter-segment kinematics during walking and running. Paired-sample t-test from statistical parametric mapping 1d was used to check the kinematic significance.ResultsPeak pressure in third metatarsal (M3) increased significantly during walking under manipulation. Contact area increased in second metatarsal (M2) with manipulation during running. Peak pressure and pressure-time integral illustrated significant increases in M3, and the maximum force and impulse in fourth metatarsal (M4) increased significantly. Arch height index increased while walking with toe manipulation. The foot progression angle in the frontal plane showed significant decrease in mid-swing phase during walking and significant increase in mid-stance phase during running. The hallux relative to forefoot angles presented higher axial rotation in the frontal plane.SignificanceFindings form this study showed centrally and laterally redistributed foot loadings and increased forefoot inter-segment flexibility with manipulation, which may be used as baseline to evaluate toe-manipulation interventions in foot disorders, specifically hallux valgus deformity.     

A comparison of gait initiation and termination methods for obtaining plantar foot pressures

The midgait protocol is the most commonly used method to collect pressure platform data. Spatial limitations, however, frequently render this technique unsuitable. Alternative gait protocols have focused on gait initiation procedures in obtaining data. The current study investigated whether a commonly cited two-step gait initiation protocol, or a two-step gait termination protocol produced pressure data more representative of the criterion, midgait method. A pressure platform was used to collect data for 25 asymptomatic subjects using the midgait, two-step gait initiation and two-step gait termination walking protocols. The contact duration, percentage contact duration, peak pressure, peak force, pressure–time integral and force–time integral were calculated for seven sites within the foot. Multivariate analysis of variance with repeated measures identified significant protocol by site interactions for all variables except the force-time integral. The gait initiation protocol, although having minimal effect on peak pressures beneath the forefoot, markedly altered the relative timing parameters of the foot. In contrast, the gait termination protocol had minimal effect on temporal parameters, but resulted in a reduction in pressures beneath the forefoot. Abbreviated gait protocols are often employed in plantar pressure studies. This study suggests that the choice between a gait initiation and termination protocol is largely dependent on the gait parameter of interest.     

Can the Foot Posture Index or their individual criteria predict dynamic plantar pressures?

The Foot Posture Index (FPI) quantifies foot posture through the evaluation of six individual criteria. The objective of the present study was then to establish the plantar pressure differences between types of feet, and to study the capacity of the whole FPI value and the six individual criteria to predict the pattern of plantar pressures.In a sample of 400 healthy subjects (201 men and 199 women), the FPI was evaluated and plantar pressures were measured in 10 zones using the Footscan^® platform. Five plantar pressures measurements were made for each foot, using for the study the mean of these measurements for each subject's left foot.The hallux and the lesser toes had lower pressure indices in highly supinated feet, with the values increasing progressively toward the highly pronated feet (p < 0.001 and p = 0.019 respectively). The fifth metatarsal head (MTH) values were greater in highly supinated feet, and decreased in the highly pronated feet (p < 0.001). The FPI value predicts low variability of plantar pressures, mainly in the heel and midfoot, while the individual criteria predict higher variability in the forefoot. The talonavicular prominence and the calcaneal frontal plane position was the most influential criterion, explaining 8.5% of the hallux pressure and 11.1% of the fifth MTH pressure. Neither talar head palpation nor the supra and infra malleolar curvature predicted any of the plantar pressures variables.The FPI can distinguish three groups of feet – pronated, neutral, and supinated. Its individual criteria predict moderate or low plantar pressures variability, with the talonavicular prominence being the most influential criterion.     

Plantar pressure distribution during barefoot standing, walking and landing in preschool boys.

The purpose of this study was to examine the pressure distribution under the foot in preschool boys during standing, landing and walking tasks. Fourteen healthy boys (age 3.20+/-0.4 years) performed five activities (standing on one foot, standing on two feet, landing from a height onto one foot and both feet, and walking) on a Musgrave pressure platform system. The peak pressures were determined for eight areas of the foot. One-way analysis of variance (ANOVA) indicated that the total plantar pressures during landings were significantly higher compared to the overall plantar pressure developed during standing on one foot or two-feet and the contact phase of walking (P<0.05). A two-way ANOVA indicated that with the exception of the second to fifth toe area, the pressures were significantly higher elsewhere during landing and walking compared with the pressures during standing on two feet (P<0.05). Neither standing nor the stance phase of walking is fully representative of foot function in children.     

Age-related differences in foot structure and function

The aim of this study was to compare foot characteristics and plantar force and pressure patterns in young and older people. Fifty young (mean age 20.9+/-2.6 years) and 50 older (mean age 80.2+/-5.7 years) people without foot problems underwent tests of foot posture, range of motion, strength, sensation and deformity. Plantar force and pressure distribution during gait were evaluated using a floor-mounted resistive sensor mat system. Older participants exhibited flatter/more pronated feet, reduced range of motion of the ankle and 1st metatarsophalangeal joints, a higher prevalence of hallux valgus, toe deformities and toe plantarflexor weakness, and reduced plantar tactile sensitivity. Plantar pressure analysis revealed decreased magnitude of forces and pressures under the heel (-13% to 16%), metatarsophalangeal joints (-11% to 16%) and hallux (-19% to 25%), but greater relative contact time under the heel (+21%), midfoot (+14%) and metatarsophalangeal joints (+5% to 8%) in older participants. Multiple regression analysis revealed that these age-related differences could be largely explained by differences in step length and various foot characteristics, particularly foot posture and the severity of hallux valgus. These findings indicate that ageing is associated with significant changes in foot characteristics which contribute to altered plantar loading patterns during gait.     

A comparison of external plantar loading and in vivo local metatarsal deformation wearing two different military boots

The introduction of the M90 boot with a more flexible outer sole to military recruits in Sweden was accompanied by an increase in second metatarsal stress fractures. This study compared the new boot with the previous, stiffer model. A combination of external plantar pressure measurement (two subjects) and an in vivo measurement of dorsal metatarsal strain (six subjects) using strain gauge instrumented staples was implemented. Walking in both boot models resulted in increased plantar pressure under the heads of the lesser metatarsals and generally decreased loading under the remainder of the foot. Dorsal metatarsal tension increased for subjects wearing the new boot throughout a walking protocol.     

Pressure distribution in Morton's foot structure

The Morton foot structure (MFS) is a foot having, as its most prominent distinguishing feature, a second metatarsal head which is more distally placed than the head of the first. This structure has been associated with a variety of foot problems in athletes. The origin of these foot problems has been hypothesized to be an abnormal metatarsal head loading pattern found in the MFS. This study was conducted to determine whether the MFS produced a metatarsal head pressure profile which was different from the non-Morton foot. Plantar pressure distributions during walking were collected using a 1000 element piezoceramic pressure platform from the feet of 45 subjects (30 classified as having the MFS and 15 non-Morton or control subjects). The protrusion of the head of the second metatarsal beyond the first metatarsal head was determined by palpation and varied between 0.8 and 2.8 cm for the experimental group. Pressure distributions were collected from a mid-gait step onto the platform at a speed of 1.6 to 2 m.s-1 using a 15 m runway. Peak pressures and impulse values were determined for three forefoot regions. Results show that peak loading in both groups occurred under the second metatarsal but that the magnitudes of second metatarsal peak pressures were significantly higher in the MFS group (P less than 0.005). The results suggest that, although the loading pattern between MFS and normal feet is similar, the significantly higher second metatarsal head peak pressure in the MFS may predispose this foot type to problems associated with excessive localized pressure.     

Plantar pressure asymmetry and risk of stress injuries in the foot of young soccer players

BackgroundAsymmetries in the magnitude of plantar pressure are considered a risk factor for stress fracture of the fifth metatarsal in soccer athletes.ObjectiveTo investigate the presence of plantar pressure asymmetries among young soccer athletes.DesignObservational.SettingLaboratory.ParticipantsThirty young adolescents divided into a soccer player group (n = 15) or a matched control group (n = 15).Main outcome measuresMean plantar pressure was determined for seven different regions of the foot. Data were compared between the preferred and non-preferred foot, and between the groups, during barefoot standing on a pressure mat system.ResultsHigher pressure was found in the hallux, 5th metatarsal and medial rearfoot of the non-preferred foot in the young soccer players. These asymmetries were not observed in the control group. Magnitudes of plantar pressure did not differ between the groups.ConclusionYoung soccer players present asymmetries in plantar pressure in the hallux, 5th metatarsal and medial rearfoot, with higher pressure observed in the non-preferred foot.     

Effects of running-induced fatigue on plantar pressure distribution in novice runners with different foot types

This study aimed to assess the effects of running-induced fatigue on plantar pressure parameters in novice runners with low and high medial longitudinal arch. Plantar pressure data from 42 novice runners (21 with high, and 21 with low arch) were collected before and after running-induced fatigue protocol during running at 3.3 m/s along the Footscan^® platform. Peak plantar pressure, peak force and force-time integral (impulse) were measured in ten anatomical zones. Relative time for foot roll-over phases and medio-lateral force ratio were calculated before and after the fatigue protocol. After the fatigue protocol, increases in the peak pressure under the first-third metatarsal zones and reduction under the fourth–fifth metatarsal regions were observed in the low arch individuals. In the high arch group, increases in peak pressure under the fourth–fifth metatarsal zones after the running-induced fatigue was observed. It could be concluded that running-induced fatigue had different effects on plantar pressure distribution pattern among novice runners with low and high medial longitudinal foot arch. These findings could provide some information related to several running injuries among individuals with different foot types.     

External feedback during walking improves measures of plantar pressure in individuals with chronic ankle instability

BackgroundIndividuals with chronic ankle instability (CAI) commonly present with an altered walking gait which favors the lateral aspect of their foot. Current rehabilitative protocols are unable to address these gait modifications which are potentially hindering improvements in patient-reported outcomes. Protocols for gait retraining are scarce, thus there is a need to develop intervention strategies and instruments to specifically target foot motion to address gait deficits in individuals with CAI.Research QuestionTo determine the ability of a novel laser device providing external visual feedback (ExFB) during real-time to cause alterations in plantar pressure measures in individuals with CAI.MethodsTwenty-six participants with CAI walked on a treadmill while real-time plantar pressure measures were being recorded during a baseline and feedback condition. Baseline trials were compared with ExFB trials within each subject.ResultsThe ExFB condition was able to significantly reduce plantar pressures on the lateral midfoot and forefoot compared to baseline. A statistically significant medial shift in center of pressure trajectory was also observed in the ExFB condition compared to baseline.SignificanceReal-time external feedback provided by a novel laser device has the ability to reduce lateral column plantar pressures during walking in individuals with CAI.     

Longitudinal study of foot pressures during real-world walking as infants develop from new to confident walkers

BackgroundOnset of walking in infants leads to regular cyclic loading of the plantar foot surface for the first time. This is a critical period for evolving motor skills and foot structure and function. Plantar pressure literature typically studies gait only once walking is established and under conditions that artificially constrain the walking direction and bouts compared to how infants move in the real-world. We therefore do not know how the foot is loaded when self-directed walking is first achieved and whether it changes as walking is practiced.Research questionHow do pressures on the plantar foot in real-world walking change from new to confident walking?MethodsFifty-seven infants participated in a two-site longitudinal study. Bespoke child-friendly spaces incorporated large pressure platforms and video. Data was collected at two milestones: new (403 days) and confident (481 days) walking. Steps were defined as walking straight or turning medially/laterally. Pressure variables were calculated for eight-foot regions and compared between milestones.ResultsConfident walking resulted in more steps (median: 18 v 35) and almost twice as many turning steps. During straight-line steps, confident walking increased peak pressures in the medial heel (median: 99.3 v 106.7kPa, p < .05) and lateral forefoot (median: 53.9 v 65.3kPa, p < .001) and reduced medial toe pressure (median: 98.1 v 80.0kPa, p < .05). Relative medial midfoot contact area reduced (median: 12.4 v 11.2%, p < .05) as absolute foot contact increased. A faster transition across stance and a reduced relative contact time in the forefoot were recorded in confident walking.SignificancePressures change rapidly as walking is initiated with significant differences in foot loading evident within an average 77 days. Importantly, these changes differ in straight and turning walking. Continued reliance on assessment of straight-line walking during early stages of ambulation likely fails to characterise 26% of steps experienced by infant feet.     

Effect of gait speed changes on foot loading characteristics in children

Gait speed has been shown to influence foot loading patterns in adults but the mechanism has not been investigated in children. The present study investigated the effects of changes in gait speed on foot loading characteristics in 20 typically developing children who participated in plantar pressure measurements at normal, slow and fast walking speeds. In spite of shorter contact times in the fast walking speed condition, significantly increased foot loading was seen in the hindfoot, medial and central forefoot and toes while it slightly decreased in the lateral midfoot and forefoot. The results generally confirm the findings in adults that gait speed does not uniformly affect foot loading characteristics and that these effects should be kept in mind when comparing different subject groups or children at repeated measurement occasions.     

Between-day reliability of repeated plantar pressure distribution measurements in a normal population

The objective of this study was to determine the reliability of repeated plantar pressure distribution measurements during normal gait across multiple testing sessions. Testing sessions were conducted on 5 separate days at approximately the same time of day. Nine subjects (five males, four females, age 26 ± 8.4 years) who were free of any musculoskeletal injury were recruited. A capacitive pressure distribution platform (EMED AT, Novel GmbH, Munich, Germany), sampling at 50 Hz was used to collect plantar pressure patterns during barefoot walking at a self-selected speed. Four parameters were investigated: peak pressure, maximum force, impulse, and contact time, and these were investigated in 10 areas of the foot after using the PRC mask method of subdividing the foot into ten anatomical areas of interest. Individual means of all the five repeated trials for each foot were calculated, and these values were used to calculate intraclass correlation coefficients (ICC) and coefficients of variation (CoV) for all parameters. The results of this investigation show a generally good level of reliability, the quality of which is dependent on the region of the foot and the parameter investigated. Areas with typically high loading characteristics, such as the central forefoot showed a higher level of reliability in the ICC's (>0.9) than less loaded areas such as the medial midfoot (<0.8). The conclusion of this study is that plantar pressure distribution measurements can be used in comparative evaluations since the measures of repeatability are satisfactory for the parameters and foot regions usually used in the investigation of clinical populations such as neuropathic diabetics.