Foot type and overuse injury in triathletes

Reductions in rearfoot eversion posture due to proximal muscle strengthening are dependent on foot-ankle varus alignment

BACKGROUND

Strengthening the hip and trunk muscles may decrease foot pronation in upright standing due to expected increases in hip passive torque and lower-limb external rotation. However, considering the increased pronation caused by a more varus foot-ankle alignment, subjects with more varus may experience smaller or no postural changes after strengthening.

OBJECTIVE

To investigate the effects of hip and trunk muscle strengthening on lower-limb posture during upright standing and hip passive torque of women with more and less varus alignment.

METHODS

This nonrandomized controlled experimental study included 50 young, able-bodied women. The intervention group (n = 25) performed hip and trunk muscle strengthening exercises, and the control group (n = 25) maintained their usual activities. Each group was split into two subgroups: those with more and less varus alignment. Hip, shank, and rearfoot-ankle posture and hip passive external rotation torque were evaluated. Mixed analyses of variance and preplanned contrasts were used to assess prepost changes and between-group differences (α = 0.05).

RESULTS

The less-varus subgroup of the intervention group had a reduced rearfoot eversion posture (P = 0.02). No significant changes were observed in the less-varus subgroup of the control group (P = 0.31). There were no significant differences in posture between the control and intervention groups when varus was not considered (P ≥ 0.06). The intervention group had increased hip passive torque (P = 0.001) compared to the control group, independent of varus alignment.

CONCLUSION

Despite the increases in hip passive torque, the rearfoot eversion posture was reduced only in women with a less-varus alignment. Having more foot-ankle varus may prevent eversion reductions.

Effect of gender and running experience on lower limb biomechanics following 5 km barefoot running

Barefoot running has been increasing in popularity, yet there is a gap in understanding concerning the biomechanics of mid-distance barefoot running, especially between genders and runners of different running-experience levels. This study examines the effects of running-experience, gender, and their interaction on running biomechanics following 5 km barefoot running. Before and after a 5 km run, three-dimensional kinematics and kinetics of the lower limb joints and plantar pressure during barefoot running were collected from 20 participants. Participants were stratified by their running-experience levels (novice and marathon-experienced) and gender. This study revealed significant gender effects on lower limb biomechanics following a 5 km barefoot run. Increased plantar pressure under the lateral aspect of the foot was observed in the female cohort, while the male cohort exhibited reduced plantar pressure under the lateral heel. This study suggests that modified lower limb running biomechanics and modified lateral foot loading after 5 km barefoot running may create a different foot loading environment for female and male runners that should be accommodated in barefoot runningand minimalist shoe design.

The association between foot posture, single leg balance and running biomechanics of the foot

OBJECTIVES

A mal-aligned foot posture (high-arched and flat feet) and poor single leg balance ability have been separately associated with foot injuries during running. Therefore, clinicians assess these routinely. However, the extent to which foot posture and single-leg balance ability affect actual foot biomechanics during running is not known. This study aims to investigate the association of foot posture, single-leg balance ability, and foot biomechanics during running.

METHOD

This is a cross sectional study of sixty-nine participants who had their foot postures and single-leg balance ability assessed. The Foot Posture Index and Balance Error Scoring System were used. Their foot kinetics was measured as they ran on an instrumented treadmill and foot kinematics was processed using a 3D motion capture system. Multiple-regression was used to analyse the variance of foot biomechanics explained by foot posture and single-leg balance ability.

RESULTS

Foot posture and single-leg balance ability were found to account significantly for the variance in rearfoot eversion (24%) and forefoot dorsiflexion (7%). Two regression equations were derived, where rearfoot eversion and forefoot dorsiflexion during running may be predicted.

CONCLUSION

Foot posture and single-leg balance ability can predict rearfoot eversion and forefoot dorsiflexion only during running. Based on the regression equations, individuals with the same foot posture but different single-leg balance ability may exhibit different foot kinematics. However, the angular differences are small. The equations may be useful for clinicians working in places where running gait analysis equipment are not readily accessible. Further studies with larger sample sizes are required to validate these equations. In addition, further studies are necessary to investigate the effect of these two variables under different running conditions e.g. with footwear and with orthoses.

Immediate comfort perception of 3D-printed foot orthoses in individuals with unilateral heel pain

BACKGROUND

Custom-made foot orthoses (FOs) play an integral part in managing foot disorders. Traditional FO fabrication is time-consuming and labor intensive. Three-dimensional (3D) printed FOs save time and cost compared with the traditional manufacturing process. To date, the differences in dimensions and comfort perception of these orthoses have not been compared in a pathological population.

OBJECTIVE

Compare the dimensions between 3D-printed and traditionally made FOs and comfort perception between 3D-printed, traditionally made, and no FOs in individuals with flatfeet and unilateral heel pain.

STUDY DESIGN

Within-subject single-blinded randomized crossover study design.

METHODS

Thirteen participants had custom-made FOs using 3D-printing and traditional processes. Orthotic lengths, widths, arch heights, and heel cup heights were compared. Participants performed walking trials under three conditions: (1) no orthoses, (2) 3D-printed orthoses, and (3) traditionally made orthoses. Comfort perception was recorded. Orthotic dimensions were compared using paired t tests, and comfort perception were compared using one-way multiple analysis of variance and Bonferroni post hoc tests.

RESULTS

Three-dimensional-printed orthoses were wider, have higher arch heights, and heel cup heights compared with traditionally made FOs (medium to large effect sizes). There was a difference in comfort perception between the three orthotic conditions, F(12,62) = 1.99, P = 0.04; Wilk Λ = 0.521, ηp2= 0.279. Post hoc tests show that there is no difference in comfort perception between the 3D-printed and traditionally made FOs. Both FOs were significantly more comfortable than no orthoses.

CONCLUSIONS

Three-dimensional printing seems to be a viable alternative orthotic fabrication option. Future studies should compare the biomechanical effects of 3D-printed and traditionally made FOs.

Forefoot Injuries in Athletes: Integration of the Movement System

Despite the prevalence of forefoot related problems in athletes, there are few comprehensive summaries on examination and intervention strategies for those with forefoot related symptoms. While many factors may contribute to pathology and injury, the presence of abnormal foot alignment can negatively affect lower extremity biomechanics and be associated with injuries. Physical therapists may use the characteristics associated abnormal pronation or abnormal supination to describe the movement system disorder and serve as a guide for evaluating and managing athletes with forefoot pathologies. Athletes with an abnormal pronation movement system diagnosis typically demonstrate foot hypermobility, have decreased strength of the tibialis posterior muscle, and present with a medially rotated lower extremity position. Athletes with abnormal supination movement system diagnosis typically demonstrate foot hypomobility, decreased strength of the fibularis muscles, and a laterally rotated lower extremity position. Interventions of manual therapy, taping, strengthening exercises, and neuromuscular reeducation can be directed at the identified impairments and abnormal movements. The purpose of this clinical commentary is to integrate a movement system approach in pathoanatomical, evaluation, and intervention considerations for athletes with common forefoot pathologies, including stress fractures, metatarsalgia, neuroma, turf toe, and sesamoiditis. By applying a prioritized, objective problem list and movement system diagnosis, emphasis is shifted from a pathoanatomical diagnosis-based treatment plan to a more impairment and movement focused treatment.

LEVEL OF EVIDENCE

5.

The Association Between Foot Structure and Foot Kinematics During Slow Running

BACKGROUND

Clinicians routinely assess foot posture as part of their assessment and management of foot pathologies. Flat or high-arched foot postures have been linked to kinematic deviations and increased risk of foot injuries. The Foot Posture Index (FPI) is a valid clinical tool used to classify feet into high-arched, normal-arched, and flat foot groups and predicts foot function during walking well. Walking and running are distinct locomotion styles, and studies have not been performed to correlate FPI to foot function during running. This study aims to investigate the association of FPI scores to foot kinematics during running. The results will further inform clinicians who perform static assessment of feet of individuals who are runners.

METHODS

Sixty-nine participants had their feet assessed using the FPI scoring system. Based on these scores, the feet were categorized as flat foot, normal-arched, and high-arched. Rearfoot eversion and forefoot dorsiflexion (arch flattening) of the foot were analysed during slow running between 1.4 and 2.2 m/sec. The Pearson correlation was used to analyse the FPI scores on an interval scale, with Cohen's d used to report effect size. One-way analysis of variance and a Bonferroni post hoc test was used to analyze data by category. Level of significance was set at P < .05.

RESULTS

Thirty-four flat feet, 26 normal-arched feet, and nine high-arched feet were analyzed. The FPI scores correlated significantly with rearfoot eversion (moderate effect size) and forefoot dorsiflexion (low effect size). Rearfoot eversion was greatest in the flat foot, followed by the normal-arched foot and the high-arched foot. Forefoot dorsiflexion was significantly higher in the flat foot compared with the high-arched group.

CONCLUSIONS

Foot Posture Index scores are positively correlated with rearfoot eversion and forefoot dorsiflexion during running. Clinicians can use this information to aid their foot assessment and management of individuals who are runners.

Risk Factors Influencing the Incidence of Ankle Sprain Among Elite Football and Basketball Players: A Prospective Study

Introduction. The objective of the present study was to investigate whether certain intrinsic factors (foot hyperpronation, generalized joint laxity) and clinical tests (anterior drawer and talar tilt tests, single-leg balance test and star excursion balance test, ankle and first metatarsophalangeal range of motion) could predict the incidence of lateral ankle sprains among elite football and basketball players during a full year. Method. In a prospective cohort study, 106 elite basketball and football players were recruited. During the preseason period, players underwent baseline measurements. Team physicians in following year reported occurrence of new ankle sprains. Results. Ankle sprain was more frequent among basketball players (P = .01). The history of recurrent (P = .001) and acute ankle sprain (P = .01) and each 5-year increase in age (P = .039) were predictive factors for ankle sprain. No evidence for relationship between other risk factors and occurrence of ankle sprain were achieved. Conclusion. In our study, the history of recurrent and acute ankle sprain was the strongest predictor for ankle injuries. Considering the limitations of this study, it seems mandatory to conduct more prospective studies with a larger sample size and longer follow-up period.Levels of Evidence: Level II: Prognostic.

FOOT ALIGNMENT IN SYMPTOMATIC NATIONAL FOOTBALL LEAGUE (NFL) ATHLETES: A WEIGHTBEARING CT ANALYSIS

Objective:

Our aim was to describe the foot alignment in National Football League (NFL) players with different symptomatic foot and ankle pathologies using weightbearing cone-beam computed tomography (WBCBCT), comparing them to normally aligned feet as control group.

Methods:

41 feet (36 active NFL players) were assessed using WBCBCT and compared to 20 normally aligned controls from a normal population. Measurements included: Foot and Ankle Offset (FAO); Calcaneal Offset (CO); Hindfoot Alignment Angle (HAA); angle between inferior and superior facets of the talus (Inftal-Suptal); angle between inferior facet of the talus and the horizontal/floor (Inftal-Hor); Forefoot Arch Angle (FAA); navicular- and medial cuneiform-to-floor distance.

Results:

NFL athletes showed a neutrally aligned hindfoot when compared to controls (FAO: 1% vs 0.5%; CO: 2.3 mm vs 0.8 mm; HAA: 2.9° vs 0.8° in two groups, with all p > 0.05) and a normal morphology of the subtalar joint (no difference in Inftal-Suptal and Inftal-Hor angles). Conversely, in athletes we found a decreased medial longitudinal arch (FAA: 15° vs 18.3°, p = 0.03) with smaller navicular (38.2 mm vs 42.2 mm, p = 0.03) and medial cuneiform (27 mm vs 31.3 mm, p = 0.01) mean distances to the floor when compared to controls.

Conclusion:

In our series, NFL players presented a lower medial longitudinal arch than controls but a neutrally aligned hindfoot. WBCBCT may help shed light on anatomical risk factors for injuries in professional players. Level of Evidence III, Retrospective comparative study.

Effects of corrective insole on leg muscle activation and lower extremity alignment in rice farmers with pronated foot: a preliminary report

BACKGROUND

Execution of strenuous activities in conjunction with slippery and viscous muddy working terrain in rice cultivation leads to a high prevalence of farmer musculoskeletal disorders and malalignments. Recommended intervention strategies originally designed for congenitally disabled individuals may also be applicable to farmers, including simple corrective wedges to reduce foot eversion. The objective of the present study was to conduct a preliminary investigation of the effects of corrective wedges on lower extremity muscle activity and alignment when subjects stood on flat rigid ground or muddy terrain, simulating typical work conditions encountered by the unique but populous Thai rice farming workforce.

METHODS

Nine healthy farmers with pronated feet were recruited to participate and wedges were custom fabricated for each farmer based on physical therapy assessment and use of rapid prototyping techniques. Participants were asked to stand barefoot or with wedges on the two surface types.

RESULTS

Results revealed foot pronation and knee valgus to improve (ranging, on average between 5.5 and 16.1 degrees) when participants were equipped with corrective wedges. The muscle activity of the peroneus longus and the tibialis anterior increased for muddy terrain, as compared with the rigid surface. In general, the wedges induced less tibialis anterior activity and greater peroneus longus activity, compared to when participants were standing barefoot. An elevation in evertor muscle activity may reflect stretching of the shortened muscle as a result of the reduced degree of foot pronation.

CONCLUSIONS

Findings demonstrate potential benefits of corrective insole usage for farmers with pronated feet, including improved lower extremity alignment and invertor muscle activity reduction for both rigid and muddy terrains.

Orthopaedic medical examination for young amateur athletes: a repeated cross-sectional study from 2014 to 2018

OBJECTIVES

Medical examinations for adult elite athletes are performed all over the world, however, no studies in the relevant English literature have reported on orthopaedic medical examinations for young amateur athletes. The purpose of this study was to report the results of orthopaedic medical examinations of the spine and lower extremities in young amateur athletes.

METHODS

This repeated cross-sectional study from 2014 to 2018 included a total of 323 young amateur athletes (age, 12-18 years) who were active in one of the following four sports: boxing, canoeing, weightlifting and track and field. The orthopaedic medical examination consisted of six assessments (physical examinations, the generalised joint laxity, muscle and joint tightness, static alignment and muscle volume of the lower extremities and the medial longitudinal arch of the foot). Questions regarding pain in the spine and lower extremities were also performed.

RESULTS

Among 323 young amateur athletes, 17 (5.3%) had received orthopaedic treatment at the time of the medical examination, with spondylolysis being the most common cause (29.4%, 5/17). Among 306 young athletes who had not received orthopaedic treatment, 61 (19.9%) had at least one positive finding in physical examinations or had pain in the spine or lower extremities. Anterior drawer test of the ankle and Kemp test for the spine accounted for 34% and 28% of positive findings, respectively. Low back pain and knee pain accounted for 58% and 16% of pain, respectively.

CONCLUSIONS

The present study showed that approximately one-fifth of young amateur athletes who had not received orthopaedic treatment had pain in the spine and lower extremities and positive findings in physical examinations that may require orthopaedic treatments. In addition to the early detection of injuries, orthopaedic medical examinations for young amateur athletes provide an opportunity to educate such athletes.

Randomized Clinical Trial: The Effect of Exercise of the Intrinsic Muscle on Foot Pronation

Background: There is little scientific evidence regarding the effectiveness of strengthening exercises on the foot's intrinsic musculature in improving the lower limb on the statics and dynamics in healthy individuals. Method: To evaluate the effect on foot posture with regard to the reinforcement of the short foot exercise (SFE) compared to another without a recognized biomechanical action, which we called the "non-biomechanical function" (NBF) exercise. A randomized clinical trial was carried out with 85 asymptomatic participants with a bilateral Foot Posture Index (FPI) greater than 6 points. An experimental group (n = 42) did SFE training and a control group (n = 43) carried out NBF exercises. The foot posture was evaluated twice via the navicular drop (ND) test, and the FPI was assessed on the day of inclusion in the study (pre-intervention) and after four weeks of training (post-intervention). Results: Statistically significant values were not found in foot posture between the experimental and the control groups when comparing before and after the training. However, the foot posture was modified in both groups with respect to its initial state, and the ND value decreased. Conclusions: SFE could be considered a useful tool to deal with pathologies whose etiology includes excessive pronation of the foot.

Longitudinal Analysis of Plantar Pressures with Wear of a Running Shoe

Running shoes typically have a lifespan of 300–1000 km, and the plantar pressure pattern during running may change as the shoe wears. So, the aim of this study was to determine the variation of plantar pressures with shoe wear, and the runner’s subjective sensation. Maximun Plantar Pressures (MMP) were measured from 33 male recreational runners at three times during a training season (beginning, 350 km, and 700 km) using the Biofoot/IBV^® in-shoe system (Biofoot/IBV^®, Valencia, Spain). All the runners wore the same shoes (New Balance^® 738, Boston, MA, USA) during this period, and performed similar training. The zones supporting most pressure at all three study times were the medial (inner) column of the foot and the forefoot. There was a significant increase in pressure on the midfoot over the course of the training season (from 387.8 to 590 kPa, p = 0.003). The runners who felt the worst cushioning under the midfoot were those who had the highest peak pressures in that area (p = 0.002). The New Balance^® 738 running shoe effectively maintains the plantar pressure pattern after 700 km of use under all the zones studied except the midfoot, probably due to material fatigue or deficits of the specific cushioning systems in that area.

Is There Any Association Between Foot Posture and Lower Limb-Related Injuries in Professional Male Basketball Players? A Cross-Sectional Study

BACKGROUND

Several studies have shown that foot posture is related to the incidence of ankle sprains in athletes and in nonathletic populations, but this association has not previously been considered in basketball players. This study investigates the relationship between foot posture and lower limb injuries in elite basketball players.

DESIGN AND METHOD

Two hundred twenty participants were recruited as a convenience sample. The players had a mean age of 22.51 ± 3.88 years and a body mass index of 23.98 ± 1.80. The players' medical records were accessed from the preceding 10 years, and injuries were recorded according to their location (knee, foot, and/or ankle). In addition, the Foot Posture Index (FPI) was scored for each player, and their playing positions were noted.

RESULTS

An average FPI score of 2.66 was obtained across all players, with guards presenting a significantly lower average FPI of -0.48 (P < 0.001) compared with the rest of playing positions, indicating a more supinated foot. However, center players presented an average FPI of 5.15 (P < 0.001), indicating a more pronated foot. The most common injuries observed were lateral ankle sprain (n = 214) and patellar tendinopathy (n = 126). Patellar tendinopathy was more common in supinated feet (30.08%) compared with 20.7% and 19.8% in pronated and neutral feet, respectively.

CONCLUSIONS

The most common lower limb injuries observed in basketball players were lateral ankle sprain and patellar tendinopathy. Patellar tendinopathy was more commonly associated with the supinated feet. Guard players tended to have a more supinated foot, whereas centers presented a more pronated foot.

THE EFFECT of KINESIO TAPE® on STATIC FOOT POSTURE, PLANTAR PRESSURE, and REARFOOT MOTION in INDIVIDUALS with PRONATED FEET

Background

Kinesio Tape® (KT) is an elastic therapeutic tape that is applied to the skin for treatment of sport-related injuries. Its application has been purported to facilitate the neuromuscular system, thus altering skeletal muscle activity to increase joint range of motion and improve performance. Due to its proposed therapeutic effect, KT may benefit individuals with excess foot pronation in order to decrease pain and improve function. Unfortunately, current research regarding the ability of KT to alter foot biomechanics is limited.

Purpose

The purpose of this study was to determine if the application of KT to the ankle and lower leg would alter static foot posture, plantar pressure, and foot motion during walking in individuals with foot pronation.

Study Design

Prospective Cohort Study.

Methods

Thirty participants (10M/20F) were recruited for this study. Each participant had their dorsal arch height and midfoot width measured prior to the application of the KT. In addition, their dynamic rearfoot eversion and plantar pressure was recorded during walking using an electrogoniometer and plantar pressure system. After these measurements were collected, KT was applied to their right foot and lower leg in order to attempt to facilitate activity in the posterior tibialis muscle. After applying the tape, the above measurements were repeated.

Results

None of the variables measured were statistically significantly different between the pre-test and post-test.

Conclusion

Application of KT did not result in a change in static foot posture, plantar pressure, and frontal plane rearfoot motion during walking. As such, KT cannot be recommended as a treatment for reducing excessive foot pronation where such a goal would be beneficial.

Level of Evidence

Level 3.

Foot Alignment in Symptomatic National Basketball Association Players Using Weightbearing Cone Beam Computed Tomography

Background:

Weightbearing cone beam computed tomography (WB CBCT) allows detailed 3-dimensional imaging of the foot and ankle in a weightbearing state and provides improved accuracy and reliability of foot alignment measures, especially when compared with conventional radiographic views.

Purpose:

To describe the foot alignment in National Basketball Association (NBA) players with different symptomatic foot and ankle injuries using WB CBCT and to determine if any predominant morphotype would be identified.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A total of 45 active NBA players (mean age, 24.4 years [range, 20-34 years]; N = 54 feet [29 right, 25 left]) were assessed using WB CBCT. Measurements included the following: (1) foot and ankle offset (FAO), (2) calcaneal offset (CO), (3) hindfoot alignment angle (HAA), (4) angle between the inferior and superior facets of the talus (Inftal-Suptal), (5) angle between the inferior facet of the talus and the horizontal floor line (Inftal-Hor), (6) forefoot arch angle (FAA), (7) navicular-to-floor distance, and (8) medial cuneiform–to-floor distance. Measurements were then compared with values available in the literature for a “normal” foot morphotype.

Results:

Among the 54 feet, the mean FAO was 0.48% (95% CI, –0.25% to 1.21%), the mean CO was 1.18 mm (95% CI, –0.50 to 2.87 mm), and the mean HAA was 1.42° (95% CI, –0.80° to 3.65°). The mean Inftal-Suptal angle was 5.31° (95% CI, 3.50°-7.12°), while the mean Inftal-Hor angle was 4.04° (95% CI, 2.56°-5.51°). The mean FAA was 15.84° (95% CI, 14.73°-16.92°), the mean navicular-to-floor distance was 38.30 mm (95% CI, 36.19-40.42 mm), and the mean medial cuneiform–to-floor distance was 26.79 mm (95% CI, 25.30-28.28 mm). None of these values were found to be significantly different when comparing forwards, guards, and centers.

Conclusion:

NBA players presenting with symptomatic foot and ankle injuries had a fairly “normal” foot morphology, with a tendency toward a varus hindfoot and a high-arched morphotype. No significant differences were found between players based on their position on the court. WB CBCT may help to shed light on anatomic risk factors for common injuries in professional players and may aid in the planning of specific prevention programs.

Association between the Foot Posture Index and running related injuries: A case-control study

BACKGROUND

Novice runners are at significantly greater risk of running-related injuries than experienced recreational runners. To develop prevention strategies for this population, it is important to identify predisposing factors that contribute to the incidence of these injuries. This study aims to assess the relationship between running-related injuries, foot posture and other factors in novice runners.

METHODS

Case-control study in 600 novice runners, classified as cases or controls based on incidence of running-related injuries. Participants' foot posture was measured using the Foot Posture Index, and we performed a descriptive analysis of the explanatory variables, comparing cases and controls. To assess the association between the injury and the presence of exposure and other explanatory variables, we performed a simple logistic regression for each variable and then fit a multivariable regression model.

FINDINGS

Our regression model showed that high supination was associated with 76.8 times higher odds of injury than a neutral Foot Posture Index score (P < 0.001). High pronation was associated with 20-fold higher odds of injury than neutral foot posture (P < 0.001). Other variables such as running surface, number of shoes used, and body mass index were also associated with injury. The model showed an acceptable predictive capacity, with an area under the ROC curve of 0.7753.

INTERPRETATION

If the association between Foot Posture Index and running-related injury is confirmed in large prospective studies, running programs for beginners should consider foot posture in efforts to prevent running-related injuries.

Foot and Soccer Referees’: A Pilot Study Searching “Performance” Throughout Prevention

Soccer refereeing is a “not-conventional” sport in which aerobic workload is prevalent. Along the years, several studies have attempted to define best markers of referees’ performance. Many studies focused their attention on field tests and their relationship with aerobic power. Instead, in this study, starting by a medical assessment satisfying the FIFA 11+ criteria for injuries prevention, we have investigated the foot of soccer referees and we have also wanted to find possible and/or unexpected improvements in performance. As performance marker, we have used the referral field test for soccer referees that is internationally validated and known as Yo-Yo test (YYiR1). While standardized foot posture index (FPI) questionnaire was used for screening foot referees conditions (40 young, all men by sex, with mean age 23.47 ± 4.36). Analyzing collected data, we have demonstrated by means of Read–Cressie Chi square test that neutral FPI is an important favor item affecting YYiR1 results. Further studies will be necessary in order to confirm our pilot investigation.

Concurrent validity of an automated algorithm for computing the center of pressure excursion index (CPEI)

Center of Pressure Excursion Index (CPEI), a parameter computed from the distribution of plantar pressures during stance phase of barefoot walking, has been used to assess dynamic foot function. The original custom program developed to calculate CPEI required the oversight of a user who could manually correct for certain exceptions to the computational rules. A new fully automatic program has been developed to calculate CPEI with an algorithm that accounts for these exceptions. The purpose of this paper is to compare resulting CPEI values computed by these two programs on plantar pressure data from both asymptomatic and pathologic subjects. If comparable, the new program offers significant benefits-reduced potential for variability due to rater discretion and faster CPEI calculation. CPEI values were calculated from barefoot plantar pressure distributions during comfortable paced walking on 61 healthy asymptomatic adults, 19 diabetic adults with moderate hallux valgus, and 13 adults with mild hallux valgus. Right foot data for each subject was analyzed with linear regression and a Bland-Altman plot. The automated algorithm yielded CPEI values that were linearly related to the original program (R²=0.99; P<0.001). Bland-Altman analysis demonstrated a difference of 0.55% between CPEI computation methods. Results of this analysis suggest that the new automated algorithm may be used to calculate CPEI on both healthy and pathologic feet.

Low Computational-Cost Footprint Deformities Diagnosis Sensor through Angles, Dimensions Analysis and Image Processing Techniques

Manual measurements of foot anthropometry can lead to errors since this task involves the experience of the specialist who performs them, resulting in different subjective measures from the same footprint. Moreover, some of the diagnoses that are given to classify a footprint deformity are based on a qualitative interpretation by the physician; there is no quantitative interpretation of the footprint. The importance of providing a correct and accurate diagnosis lies in the need to ensure that an appropriate treatment is provided for the improvement of the patient without risking his or her health. Therefore, this article presents a smart sensor that integrates the capture of the footprint, a low computational-cost analysis of the image and the interpretation of the results through a quantitative evaluation. The smart sensor implemented required the use of a camera (Logitech C920) connected to a Raspberry Pi 3, where a graphical interface was made for the capture and processing of the image, and it was adapted to a podoscope conventionally used by specialists such as orthopedist, physiotherapists and podiatrists. The footprint diagnosis smart sensor (FPDSS) has proven to be robust to different types of deformity, precise, sensitive and correlated in 0.99 with the measurements from the digitalized image of the ink mat.

Effects of different medial arch support heights on rearfoot kinematics

Background

Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait.

Methods

Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05).

Results

Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high.

Conclusion

Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait.

The relationship between arch height and foot length: Implications for size grading

OBJECTIVE

Medial longitudinal Arch Height is synonymous with classifying foot type and conversely foot function. Detailed knowledge of foot anthropometry is essential in the development of ergonomically sound footwear. Current Footwear design incorporates a direct proportionate scaling of instep dimensions with those of foot length. The objective of this paper is to investigate if a direct proportional relationship exists between human arch height parameters and foot length in subjects with normal foot posture.

METHOD

A healthy convenience sample of 62 volunteers was recruited to participate in this observational study. All subjects were screened for normal foot health and posture. Each subject's foot dimensions were scanned and measured using a 3D Foot Scanner. From this foot length and arch height parameters were obtained. Normalised ratios of arch height with respect to foot length were also calculated. The arch height parameters and the normalised arch ratios were used interchangeably as the dependent variables with the foot length parameters used as the independent variable for Simple Linear Regression and Correlation.

RESULTS

Analysis of foot length measures demonstrated poor correlation with all arch height parameters.

CONCLUSION

No significant relationships between arch height and foot length were found. The predictive value of the relationship was found to be poor. This holds significant implications for the current method of proportionate scaling of footwear in terms of fit and function to the midfoot region for a normative population.

Time Trends in Incidence and Severity of Injury Among Collegiate Soccer Players in the United States: NCAA Injury Surveillance System, 1990-1996 and 2004-2009

BACKGROUND

A number of sociocultural and environmental changes have occurred over the past several decades that may affect the risk of injury among young athletes playing soccer.

PURPOSE

To identify trends in injury incidence and severity between 2 time periods (1990-1996 and 2004-2009) in both male and female National Collegiate Athletic Association (NCAA) soccer players in the United States.

DESIGN

Descriptive epidemiology study.

METHODS

Data were analyzed from the NCAA Injury Surveillance System. The rate ratio (RR), along with the 95% Wald CI, compared incidence density in 2004-2009 relative to that in 1990-1996.

RESULTS

Overall sex-pooled injury rates were significantly lower in the 2004-2009 cohort compared with the 1990-1996 cohort (RR = 0.88; 95% CI = 0.86-0.91), and this was true for almost every category of injury studied. We observed only 1 significant sex difference between the time periods with regard to noncontact injuries, as men experienced a significant increase in rate of noncontact injuries between 1990-1996 and 2004-2009 (RR = 1.09; 95% CI = 1.02-1.17), whereas women experienced a significant decrease (RR = 0.70; 95% CI = 0.67-0.75).

CONCLUSION

These surveillance data show decreasing trends in collegiate soccer injuries. Whether these decreases are attributable to greater resources being allocated toward athlete health, injury management, or the safety of the playing environment cannot be determined. Given the prominence of soccer play in the United States, public health efforts should promote the use of this surveillance system to better inform and evaluate injury prevention practices and policies directed toward player safety.

The influence of insoles with a peroneal pressure point on the electromyographic activity of tibialis anterior and peroneus longus during gait

Background

Peroneus longus acts as a foot evertor and pronator, thus ensuring stability of the talocrural joint by curbing inversion movement of the rearfoot. Increased activation of the peroneus longus muscle in the stance phase could have a stabilising effect on the ankle joint. This study aimed to determine whether the activity of the peroneus longus muscle could be increased by the targeted use of a specially formed lateral pressure element in a customised orthopaedic insole.

Methods

This was a laboratory-based study that utilised a randomised crossover design. Thirty-four healthy participants walked along a walkway in neutral footwear wearing a control insole or a sensorimotor insole with a lateral pressure point adjacent to the tendon of the peroneus longus muscle. The electromyographic muscle activity of the peroneus longus and tibialis anterior muscles was measured using surface electromyography. Contact with the ground was recorded via two pressure sensors under the sole of the shoe. Muscle activity during the stance phase was analysed in the time and amplitude domains and compared statistically with paired t-tests for both insole types.

Results

In 27 out of the 34 participants, an additional activity peak of the peroneus longus muscle was observed in the loading response phase with the sensorimotor insole, which reached its maximum at 29.7 % (±4.5 %) of the stance phase. When averaged over all 34 participants, the integrated electromyographic output for the peroneus longus in the mid-stance phase revealed a significant higher activity (p < 0.001, post hoc power = 0.98, effect size: Cohen’s d = 0.71) with the sensorimotor insole (18.1 ± 11.3 % MVCs) than with the control insole (11.2 ± 7.7 % MVCs). No significant effects were established for the other gait phases or for the tibialis anterior.

Conclusions

An increase of muscle activity of the peroneus longus muscle was observed during the loading response and mid-stance phase, when orthopedic insoles with a lateral pressure point were worn. We conclude that the pressure point changes afferent information and leads to an increased peroneus longus activation in the time interval in which the pressure point exerted pressure on the peroneal tendon.

The Prevalence of Selected Intrinsic Risk Factors for Ankle Sprain Among Elite Football and Basketball Players

BACKGROUND

Lateral ankle sprains (LAS) are among the most common sports- related injuries and the reinjury rate is very high.

OBJECTIVES

This study aimed to evaluate the prevalence of some intrinsic risk factors among professional football and basketball players with or without history of acute or recurrent ankle sprain.

PATIENTS AND METHODS

One hundred and six professional football and basketball players who were referred for pre-participation examinations were recruited in this study. Prepared checklist was completed for each participant. Athletes were asked for any history of previous ankle sprain and the severity (based of self-description of signs and symptoms by the athlete), level and number of injuries in the last two years. All players were assessed for measures of foot posture index- 6, foot length and width, Beighton generalized joint laxity score, anterior drawer and talar tilt tests, star excursion and single leg balance tests and goniometric assessment of ankle plantarflexion, ankle dorsiflexion and first metatarsophalangeal dorsiflexion.

RESULTS

Forty eight basketball players (45.3%) and 58 football players (54.7%) with mean (SD) age of 19.8 (4.5) years participated. About 58.5% and 14.2% of athletes had a history of ankle sprain and recurrent sprain in at least one extremity, respectively. Sprains were more prevalent in basketball players and in dominant leg. There was no significant difference in assessed risk factors between athletes with and without history of ankle sprain, except for positive single leg balance test which was more prevalent in athletes with history of ankle sprain and also for positive talar tilt test and decreased ankle plantarflexion range of motion in acute and recurrent injury of left ankle.

CONCLUSIONS

Some intrinsic risk factors including lateral ankle ligaments laxity, balance and ankle plantarflexion seem to be related to acute or recurrent LAS in athletes. Further research is needed to reveal the role of different arthrokinematics following lateral ankle sprain.

Predicting Dynamic Foot Function From Static Foot Posture: Comparison Between Visual Assessment, Motion Analysis, and a Commercially Available Depth Camera

STUDY DESIGN :Controlled laboratory study.

OBJECTIVE

To evaluate the ability of 3 methods to assess static foot posture to predict rearfoot and midfoot kinematics during gait.

BACKGROUND

Static foot posture is commonly used clinically to infer dynamic function. Limitations of static clinical assessments may be overcome through advances in technologies, including commercially available depth cameras.

METHODS

The Foot Posture Index (FPI) of 31 males (average age, 22.5 years) was assessed using visual observation, a 3-D motion-analysis system, and a depth camera. Pearson correlations were used to evaluate relationships between FPI items and rearfoot and midfoot kinematics during walking. The ability of the static variables to predict dynamic function was assessed using multiple linear regression.

RESULTS

Most FPI items (85%) were not correlated with foot kinematics, regardless of assessment method. There were 6 fair to moderate correlations between visual FPI items and total rearfoot (r = -0.36 to -0.39, P<.05) and midfoot (r = 0.37 to 0.61, P<.05) motion, 2 fair correlations between 3-D motion-analysis FPI items and total midfoot (r = -0.43, P = .02) and peak rearfoot (r = -0.40, P = .03) motion, and 2 fair correlations between the depth-camera FPI items and average rearfoot (r = -0.38 to 0.44, P<.05) motion. Visual assessment of the FPI provided the best prediction model, explaining 37% of the variance in total midfoot inversion/eversion.

CONCLUSION

Static measures of foot posture are weakly correlated with rearfoot or midfoot kinematics, and have limited dynamic prediction ability. Our findings suggest that the FPI may not be an accurate representation of rearfoot or midfoot movement during walking, regardless of the measurement technique employed.

Foot posture is associated with kinematics of the foot during gait: A comparison of normal, planus and cavus feet

Variations in foot posture are associated with the development of some lower limb injuries. However, the mechanisms underlying this relationship are unclear. The objective of this study was to compare foot kinematics between normal, pes cavus and pes planus foot posture groups using a multi-segment foot model. Ninety-seven healthy adults, aged 18-47 were classified as either normal (n=37), pes cavus (n=30) or pes planus (n=30) based on normative data for the Foot Posture Index, Arch Index and normalised navicular height. A five segment foot model was used to measure tri-planar motion of the rearfoot, midfoot, medial forefoot, lateral forefoot and hallux during barefoot walking at a self-selected speed. Angle at heel contact, peak angle, time to peak angle and range of motion was measured for each segment. One way ANOVAs with post-hoc analyses of mean differences were used to compare foot posture groups. The pes cavus group demonstrated a distinctive pattern of motion compared to the normal and pes planus foot posture groups. Effect sizes of significant mean differences were large and comparable to similar studies. Three key differences in overall foot function were observed between the groups: (i) altered frontal and transverse plane angles of the rearfoot in the pes cavus foot; (ii) Less midfoot motion in the pes cavus foot during initial contact and midstance; and (iii) reduced midfoot frontal plane ROM in the pes planus foot during pre-swing. These findings indicate that foot posture does influence motion of the foot.

Foot posture as a risk factor for lower limb overuse injury: a systematic review and meta-analysis

Background

Static measures of foot posture are regularly used as part of a clinical examination to determine the need for foot level interventions. This is based on the premise that pronated and supinated foot postures may be risk factors for or associated with lower limb injury. This systematic review and meta-analysis investigates foot posture (measured statically) as a potential risk factor for lower limb overuse injuries.

Methods

A systematic search was performed using Medline, CINAHL, Embase, SportDiscus in April 2014, to identify prospective cohort studies that investigated foot posture and function as a risk factor for lower limb overuse injury. Eligible studies were classified based on the method of foot assessment: (i) static foot posture assessment; and/or (ii) dynamic foot function assessment. This review presents studies evaluating static foot posture. The methodological quality of included studies was evaluated by two independent reviewers, using an adapted version of the Epidemiological Appraisal Instrument (EAI). Where possible, effects were expressed as standardised mean differences (SMD) for continuous scaled data, and risk ratios (RR) for nominal scaled data. Meta-analysis was performed where injuries and outcomes were considered homogenous.

Results

Twenty-one studies were included (total n = 6,228; EAI 0.8 to 1.7 out of 2.0). There was strong evidence that a pronated foot posture was a risk factor for medial tibial stress syndrome (MTSS) development and very limited evidence that a pronated foot posture was a risk factor for patellofemoral pain development, although associated effect sizes were small (0.28 to 0.33). No relationship was identified between a pronated foot posture and any other evaluated pathology (i.e. foot/ankle injury, bone stress reactions and non-specific lower limb overuse injury).

Conclusion

This systematic review identified strong and very limited evidence of small effect that a pronated foot posture is a risk factor for MTSS and patellofemoral pain respectively. Evaluation of static foot posture should be included in a multifactorial assessment for both MTSS and patellofemoral pain, although only as a part of the potential injury risk profile. Whilst the included measures are clinically applicable, further studies are required to determine their relationship with dynamic foot function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13047-014-0055-4) contains supplementary material, which is available to authorized users.

Dynamic foot function as a risk factor for lower limb overuse injury: a systematic review

Background

Dynamic foot function is considered a risk factor for lower limb overuse injuries including Achilles tendinopathy, shin pain, patellofemoral pain and stress fractures. However, no single source has systematically appraised and summarised the literature to evaluate this proposed relationship. The aim of this systematic review was to investigate dynamic foot function as a risk factor for lower limb overuse injury.

Methods

A systematic search was performed using Medline, CINAHL, Embase and SportDiscus in April 2014 to identify prospective cohort studies that utilised dynamic methods of foot assessment. Included studies underwent methodological quality appraisal by two independent reviewers using an adapted version of the Epidemiological Appraisal Instrument (EAI). Effects were expressed as standardised mean differences (SMD) for continuous scaled data, and risk ratios (RR) for nominal scaled data.

Results

Twelve studies were included (total n = 3,773; EAI 0.44 to 1.20 out of 2.00, representing low to moderate quality). There was limited to very limited evidence for forefoot, midfoot and rearfoot plantar loading variables (SMD 0.47 to 0.85) and rearfoot kinematic variables (RR 2.67 to 3.43) as risk factors for patellofemoral pain; and plantar loading variables (forefoot, midfoot, rearfoot) as risk factors for Achilles tendinopathy (SMD 0.81 to 1.08). While there were significant findings from individual studies for plantar loading variables (SMD 0.3 to 0.84) and rearfoot kinematic variables (SMD 0.29 to 0.62) as risk factors for ‘non-specific lower limb overuse injuries’, these were often conflicting regarding different anatomical regions of the foot. Findings from three studies indicated no evidence that dynamic foot function is a risk factor for iliotibial band syndrome or lower limb stress fractures.

Conclusion

This systematic review identified very limited evidence that dynamic foot function during walking and running is a risk factor for patellofemoral pain, Achilles tendinopathy, and non-specific lower limb overuse injuries. It is unclear whether these risk factors can be identified clinically (without sophisticated equipment), or modified to prevent or manage these injuries. Future prospective cohort studies should address methodological limitations, avoid grouping different lower limb overuse injuries, and explore clinically meaningful representations of dynamic foot function.

Electronic supplementary material

The online version of this article (doi:10.1186/s13047-014-0053-6) contains supplementary material, which is available to authorized users.

The impact of triathlon training and racing on athletes' general health

Although the sport of triathlon provides an opportunity to research the effect of multi-disciplinary exercise on health across the lifespan, much remains to be done. The literature has failed to consistently or adequately report subject age group, sex, ability level, and/or event-distance specialization. The demands of training and racing are relatively unquantified. Multiple definitions and reporting methods for injury and illness have been implemented. In general, risk factors for maladaptation have not been well-described. The data thus far collected indicate that the sport of triathlon is relatively safe for the well-prepared, well-supplied athlete. Most injuries 'causing cessation or reduction of training or seeking of medical aid' are not serious. However, as the extent to which they recur may be high and is undocumented, injury outcome is unclear. The sudden death rate for competition is 1.5 (0.9-2.5) [mostly swim-related] occurrences for every 100,000 participations. The sudden death rate is unknown for training, although stroke risk may be increased, in the long-term, in genetically susceptible athletes. During heavy training and up to 5 days post-competition, host protection against pathogens may also be compromised. The incidence of illness seems low, but its outcome is unclear. More prospective investigation of the immunological, oxidative stress-related and cardiovascular effects of triathlon training and competition is warranted. Training diaries may prove to be a promising method of monitoring negative adaptation and its potential risk factors. More longitudinal, medical-tent-based studies of the aetiology and treatment demands of race-related injury and illness are needed.

Predictors of calf cramping in rugby league

Exercise-associated muscle cramps (EAMC) in the calf are common in rugby league. To date, the etiology and predictors of calf cramping are poorly understood. The aim of this study was to undertake a prospective investigation to identify predictors of calf cramping in rugby league players. Demographic and anthropometric data and calf cramp and injury history were collected in the preseason. Hydration status, number of games played, and calf cramps were recorded on game days. Male rugby league players (n = 103, mean age 18.8 ± 4.1 years) were classified as either EAMC (experienced at least 1 incident of calf cramps in the season) or no EAMC (no calf cramps). The following were investigated as possible predictors of EAMC using logistic regression modeling: competition level, age, ethnicity, playing position, history of cramping, precramping, low back pain, foot orthotic usage, foot posture, foot strike, muscle flexibility, calf girth, hydration status, and number of games played. Half the players, n = 52, experienced at least 1 incidence of calf cramping. Playing in a senior competition level (odds ratio: 0.21; 95% confidence interval: 0.06-0.75; p = 0.016), a history of calf cramping (10.85; 2.16-54.44; p = 0.004), and a history of low back pain resulting in missed field minutes (4.50, 1.37-14.79; p = 0.013) were found to predict EAMC. This study suggests that there is a high incidence of calf cramping in rugby league, especially at senior competition levels, and supports preseason screening in senior players to idetify those at risk of calf cramping and the development of possible preventative strategies.

The foot posture index: anthropometric determinants and influence of sex

BACKGROUND

The Foot Posture Index (FPI) quantifies foot posture on the basis of six criteria. Although the male foot is longer and broader than the female foot, limited evidence exists about the differences in foot posture between the sexes and which are its biological and anthropometric determinants. We sought to evaluate possible sex differences in the FPI and the determinants influencing foot posture.

METHODS

In 400 individuals (201 men and 199 women), the FPI was determined in the static bipedal stance and relaxed position. The FPI was obtained as the sum of the scores (-2, -1, 0, 1, or 2) given to each of six criteria. A multiple regression model was constructed of the overall FPI against age, weight, height, body mass index, and foot size.

RESULTS

The mean ± SD FPI was 2.0 ± 4.3 overall, 1.6 ± 4.5 for men, and 2.4 ± 4.1 for women, with the difference being nonsignificant (P = .142). The neutral posture was the most frequent (57.3%). A greater proportion of women had neutral and pronated feet, and a greater proportion of men had supinated and highly supinated feet, with the differences being nonsignificant (P = .143). Foot size, height, and body mass index together explained 10.1% of the overall FPI value (P < .001).

CONCLUSIONS

The most frequent posture was neutral with a certain degree of pronation, with no differences in FPI values between men and women. Participants with larger foot sizes had higher FPI values, whereas taller and heavier participants had lower FPI values.

Associations of foot posture and function to lower extremity pain: results from a population-based foot study

OBJECTIVE

Studies have implicated foot posture and foot function as risk factors for lower extremity pain. Empirical population-based evidence for this assertion is lacking; therefore, the purpose of this study was to evaluate cross-sectional associations of foot posture and foot function to lower extremity joint pain in a population-based study of adults.

METHODS

Participants were members of the Framingham Foot Study. Lower extremity joint pain was determined by the response to the National Health and Nutrition Examination Survey-type question, "On most days do you have pain, aching or stiffness in your (hips, knees, ankles, or feet)?" The Modified Arch Index classified participants as having planus, rectus (referent), or cavus foot posture. The Center of Pressure Excursion Index classified participants as having overpronated, normal (referent), or oversupinated foot function. Crude and adjusted (age, sex, and body mass index) logistic regression determined associations of foot posture and function to lower extremity pain.

RESULTS

Participants with planus structure had higher odds of knee (odds ratio [OR] 1.57, 95% confidence interval [95% CI] 1.24-1.99) or ankle (OR 1.47, 95% CI 1.05-2.06) pain, whereas those with a cavus foot structure had increased odds of ankle pain only (OR 7.56, 95% CI 1.99-28.8) and pain at 1 lower extremity site (OR 1.37, 95% CI 1.04-1.80). Associations between foot function and lower extremity joint pain were not statistically significant except for a reduced risk of hip pain in those with an oversupinated foot function (OR 0.69, 95% CI 0.51-0.93).

CONCLUSION

These findings offer a link between foot posture and lower extremity pain, highlighting the need for longitudinal or intervention studies.

The association between body composition and foot structure and function: a systematic review

The aim of this systematic review was to investigate the relationship between body composition and foot structure and function. Six electronic databases (Ovid MEDLINE, Ovid EMBASE, Ovid AMED, CINAHL, Scopus and The Cochrane Library) and reference lists from relevant papers were searched on 2 September 2013. Sixteen papers that reported on the association between body composition and foot structure and function met our inclusion criteria and were reviewed. The evidence indicates that obesity is strongly associated with planus (low-arched) foot posture, pronated dynamic foot function and increased plantar pressures when walking. However, there is limited evidence to support an association between other body composition measures, such as fat mass, with foot structure or function.

The foot posture index in men practicing three sports different in their biomechanical gestures

BACKGROUND

The technical gestures characteristic of certain sports may lead to one type of foot being more prevalent than the others. The Foot Posture Index (FPI) has been used as a diagnostic tool for support postures in various sports, but the differences in these postures between sports of distinct gestures in their actions are far from completely understood.

METHODS

The overall FPI, obtained as the sum of the scores of its six individual criteria, was determined in 90 male athletes (30 runners, 30 basketball players, and 30 handball players) in static bipedal stance and relaxed position. Analysis of variance was used to find significant differences among the three sports in the total FPI and its six criteria.

RESULTS

The mean ± SD FPI was 2.9 ± 2.8 in runners, 3.9 ± 4.1 in basketball players, and -0.4 ± 6.9 in handball players, with significant differences among these groups (P = .008). Significant differences were also found in the talar head position and talonavicular prominence values between handball players and runners (P = .001 and P = .004, respectively) and between handball and basketball players (P = .002 and P = .006, respectively).

CONCLUSIONS

Runners and basketball players had neutral feet, whereas handball players had supinated feet. The differences in foot posture seem to be mainly determined by two of the FPI criteria: talar head position and talonavicular prominence.

Association of planus foot posture and pronated foot function with foot pain: the Framingham foot study

OBJECTIVE

To examine the associations of foot posture and foot function to foot pain.

METHODS

Data were collected on 3,378 members of the Framingham Study cohort who completed foot examinations in 2002-2008. Foot pain (generalized and at 6 locations) was based on the response to the following question: "On most days, do you have pain, aching or stiffness in either foot?" Foot posture was categorized as normal, planus, or cavus using static pressure measurements of the arch index. Foot function was categorized as normal, pronated, or supinated using the center of pressure excursion index from dynamic pressure measurements. Sex-specific multivariate logistic regression models were used to examine the effect of foot posture and function on generalized and location-specific foot pain, adjusting for age and weight.

RESULTS

Planus foot posture was significantly associated with an increased likelihood of arch pain in men (odds ratio [OR] 1.38, 95% confidence interval [95% CI] 1.01-1.90), while cavus foot posture was protective against ball of foot pain (OR 0.74, 95% CI 0.55-1.00) and arch pain (OR 0.64, 95% CI 0.48-0.85) in women. Pronated foot function was significantly associated with an increased likelihood of generalized foot pain (OR 1.28, 95% CI 1.04-1.56) and heel pain (OR 1.54, 95% CI 1.04-2.27) in men, while supinated foot function was protective against hindfoot pain in women (OR 0.74, 95% CI 0.55-1.00).

CONCLUSION

Planus foot posture and pronated foot function are associated with foot symptoms. Interventions that modify abnormal foot posture and function may therefore have a role in the prevention and treatment of foot pain.

Mechanism of orthotic therapy for the painful cavus foot deformity

BACKGROUND

People who have extremely high arched feet or pes cavus often suffer from substantial foot pain. Custom-made foot orthoses (CFO) have been shown to be an effective treatment option, but their specificity is unclear. It is generally thought that one of the primary functions of CFO is redistributing abnormal plantar pressures. This study sought to identify variables associated with pain relief after CFO intervention.

METHODS

Plantar pressure data from a randomized controlled trial of 154 participants with painful pes cavus were retrospectively re-analyzed at baseline and three month post CFO intervention. The participants were randomized to a treatment group given CFO or a control group given sham orthoses.

RESULTS

No relationship between change in pressure magnitude and change in symptoms was found in either group. However, redistribution of plantar pressure, measured with the Dynamic Plantar Loading Index, had a significant effect on pain relief (p = 0.001). Our final model predicted 73% of the variance in pain relief from CFO and consisted of initial pain level, BMI, foot alignment, and changes in both Dynamic Plantar Loading Index and pressure-time integral.

CONCLUSION

Our data suggest that a primary function of effective orthotic therapy with CFO is redistribution of abnormal plantar pressures. Results of this study add to the growing body of literature providing mechanistic support for CFO providing pain relief in painful foot conditions. The proposed model may assist in better designing and assessing orthotic therapy for pain relief in patients suffering painful cavus foot deformity.

TRIAL REGISTRATION

Randomized controlled trial: ISRCTN84913516.

The effect of moderate running on foot posture index and plantar pressure distribution in male recreational runners

BACKGROUND

Fatigue due to running has been shown to contribute to changes in plantar pressure distribution. However, little is known about changes in foot posture after running. We sought to compare the foot posture index before and after moderate exercise and to relate any changes to plantar pressure patterns.

METHODS

A baropodometric evaluation was made, using the FootScan platform (RSscan International, Olen, Belgium), of 30 men who were regular runners and their foot posture was examined using the Foot Posture Index before and after a 60-min continuous run at a moderate pace (3.3 m/sec).

RESULTS

Foot posture showed a tendency toward pronation after the 60-min run, gaining 2 points in the foot posture index. The total support and medial heel contact areas increased, as did pressures under the second metatarsal head and medial heel.

CONCLUSIONS

Continuous running at a moderate speed (3.3 m/sec) induced changes in heel strike related to enhanced pronation posture, indicative of greater stress on that zone after physical activity. This observation may help us understand the functioning of the foot, prevent injuries, and design effective plantar orthoses in sport.

Association between foot type and lower extremity injuries: systematic literature review with meta-analysis

STUDY DESIGN

Systematic literature review with meta-analysis.

OBJECTIVES

To investigate the association between nonneutral foot types (high arch and flatfoot) and lower extremity and low back injuries, and to identify the most appropriate methods to use for foot classification.

METHODS

A search of 5 electronic databases (PubMed, Embase, CINAHL, SPORTDiscus, and ProQuest Dissertations and Theses), Google Scholar, and the reference lists of included studies was conducted to identify relevant articles. The review included comparative cross-sectional, case-control, and prospective studies that reported qualitative/quantitative associations between foot types and lower extremity and back injuries. Quality of the selected studies was evaluated, and data synthesis for the level of association between foot types and injuries was conducted. A random-effects model was used to pool odds ratio (OR) and standardized mean difference (SMD) results for meta-analysis.

RESULTS

Twenty-nine studies were included for meta-analysis. A significant association between nonneutral foot types and lower extremity injuries was determined (OR = 1.23; 95% confidence interval [CI]: 1.11, 1.37; P<.001). Foot posture index (OR = 2.58; 95% CI: 1.33, 5.02; P<.01) and visual/physical examination (OR = 1.17; 95% CI: 1.06, 1.28; P<.01) were 2 assessment methods using distinct foot-type categories that showed a significant association with lower extremity injuries. For foot-assessment methods using a continuous scale, measurements of lateral calcaneal pitch angle (SMD, 1.92; 95% CI: 1.44, 2.39; P<.00001), lateral talocalcaneal angle (SMD, 1.36; 95% CI: 0.93, 1.80; P<.00001), and navicular height (SMD, 0.34; 95% CI: 0.16, 0.52; P<.001) showed significant effect sizes in identifying high-arch foot, whereas the navicular drop test (SMD, 0.45; 95% CI: 0.03, 0.87; P<.05) and relaxed calcaneal stance position (SMD, 0.49; 95% CI: 0.01, 0.97; P<.05) displayed significant effect sizes in identifying flatfoot. Subgroup analyses revealed no significant associations for children with flatfoot, cross-sectional studies, or prospective studies on high arch.

CONCLUSIONS

High-arch and flatfoot foot types are associated with lower extremity injuries, but the strength of this relationship is low. Although the foot posture index and visual/physical examination showed significance, they are qualitative measures. Radiographic and navicular height measurements can delineate high-arch foot effectively, with only anthropometric measures accurately classifying flatfoot.

LEVEL OF EVIDENCE

Prognosis, level 2a.

Normative values for the foot posture index between right and left foot: a descriptive study

BACKGROUND

The foot posture index (FPI) is a commonly used method to quantify standing foot posture. No normative data have, however, been presented to establish the range of a normal difference and asymmetrical differences between FPI score in the right foot and in the left foot.

PURPOSE

The purpose of the present study was to establish normative values for the difference between the FPI scores across the two feet.

METHODS

Among 930 healthy adults, FPI score was quantified in both feet. Difference between the two feet was calculated as FPI score on the right foot minus the FPI score on the left foot. Based on a normal distribution of the differences, asymmetry was defined as values below or above one standard deviation (SD) from the mean. Severe asymmetry was below and above ±2SD from the mean. Normal difference was defined as the range between ±1SD.

RESULTS

A reference range for normal difference in FPI score between left foot and right foot was -2 to +2. Asymmetry scores ranged from -2 to -4 and +2 to +4, while severe asymmetry was <-4 and >4.

CONCLUSION

Normative values for the difference between FPI scores in right foot and left foot have been presented from a large sample of healthy adults. These normative values can be used to identify a normal difference or an asymmetrical difference in foot posture across feet in one individual.

The effects of prolonged running on foot posture: a repeated measures study of half marathon runners using the foot posture index and navicular height

Background

Different foot postures are associated with alterations in foot function, kinetics and the subsequent occurrence of injury. Little is known about changes in foot posture following prolonged weightbearing exercise. This study aimed to identify changes in foot posture after running a half marathon.

Methods

Foot posture was measured using the Foot Posture Index (FPI-6) and navicular height in thirty volunteer participants before and after running a half marathon. FPI-6 scores were converted to Rasch logit values and means compared for these and navicular height using an ANOVA.

Results

There was a 5 mm drop in navicular height in both feet when measured after the half marathon (P < 0.05). The FPI-6 showed a side x time interaction with an increase in score indicating a more ‘pronated’ position in the left foot of + 2 [Rasch value + 1.7] but no change in the right foot (+ 0.4 [+ 0.76]) following the half marathon.

Conclusion

The apparent differences between the FPI-6 and navicular height on the right foot may be because the FPI-6 takes soft tissue contour changes into consideration whilst the navicular height focuses on skeletal changes. The changes in foot posture towards a more pronated position may have implications for foot function, and therefore risk of injury; shoe fit and comfort and also the effect of therapeutic orthoses worn during prolonged running.

Reliability of a new supination resistance measurement device and validation of the manual supination resistance test

BACKGROUND

Kinematic observations are inconsistent in predicting lower-extremity injury risk, and research suggests that kinetic variables may be more important in this regard. Before kinetics can be prospectively investigated, we need reliable ways of measuring them clinically. A measurement instrument was manufactured that closely mirrors a manual test used to clinically estimate supination resistance force. The reliability of the instrument and the validity of the clinical test were investigated.

METHODS

The left feet of 26 healthy individuals (17 men and 9 women; mean ± SD age, 25.9 ± 9.2 years; mean ± SD weight, 77.7 ± 13.3 kg) were assessed. Foot Posture Index (FPI-6), manual supination resistance, and machine supination resistance were measured. Intrarater and interrater reliability of all of the measurements were calculated. Correlations of the supination resistance measured by the device with FPI-6, the manual supination resistance test, and body weight were investigated.

RESULTS

Interrater reliability of all of the measurements was generally poor. The supination resistance machine correlated highly with the manual supination test for the rater experienced with its use. Supination resistance measurements correlated poorly with the FPI-6 and weakly with body weight.

CONCLUSIONS

The supination resistance machine was shown to have sufficient limits of agreement for the study, but improvements need to be made for more meaningful research going forward. In this study, the force required to supinate a foot was independent of its posture, and approximately 12% of it was explained by body weight. Further work is required with a much larger sample size to build regression models that sufficiently predict supination resistance force and that will be of clinical use. The manual supination test is a valid clinical test for clinicians experienced in its use.