Effects of a foot-ankle muscle strengthening program on pain and function in individuals with knee osteoarthritis: a randomized controlled trial.

BACKGROUND: Foot-ankle exercises could improve pain and function of individuals with KOA and need to be tested. OBJECTIVE: To investigate whether an 8-week foot-ankle muscle strengthening program is effective for individuals with KOA to reduce pain and improve function. METHODS: In this randomized controlled trial, individuals diagnosed with clinical and radiographic KOA were randomized into the intervention (supervised foot-ankle strengthening exercise program three times a week for 8 weeks) or control (usual care and recommendations of the healthcare team) group. Effectiveness was assessed by changes in clinical and functional outcomes between baseline and 8 weeks with pain as the primary outcome. ANCOVA tests using the intervention group as a reference and sex, body mass index, and baseline values as covariates assessed between-group differences. RESULTS: The intervention group showed lower pain scores (-4.4 units; 95%CI = -7.5, -1.1), better function (-7.1 units; 95%CI = -12.7, -1.4), higher total functional score (-11.9 units; 95%CI = -20.7, -3.1), with confidence intervals indicating a potential for the differences to be clinically meaningful, and better scores for the 30-s chair stand test (2.7 repetitions; 95%CI = 1.1, 4.1), with a confidence interval indicating a moderate clinically meaningful difference, compared to the controls. CONCLUSION: The 8-week foot-ankle exercise program showed positive, and potentially clinically meaningful, effects on knee pain and physical function among individuals with KOA, when compared to usual care. TRIAL REGISTRATION: NCT04154059. https://clinicaltrials.gov/ct2/show/NCT04154059.

Effects of Foot-Core Training on Foot-Ankle Kinematics and Running Kinetics in Runners: Secondary Outcomes From a Randomized Controlled Trial.

This study investigated the effectiveness of an 8-week foot-core exercise training program on foot-ankle kinematics during running and also on running kinetics (impact loads), with particular interest in biomechanical outcomes considered risk factors for running-related injuries in recreational runners. A single-blind, randomized, controlled trial was conducted with 87 recreational runners randomly allocated to either the control (CG) or intervention (IG) group and assessed at baseline and after 8 weeks. The IG underwent foot-core training 3 times/week, while the CG followed a placebo lower-limb stretching protocol. The participants ran on a force-instrumented treadmill at a self-selected speed while foot-segment motion was captured simultaneously with kinetic measurements. After the intervention, there were statistically significant changed in foot biomechanics, such as: IG participants strike the ground with a more inverted calcaneus and a less dorsiflexed midfoot than those in the CG; at midstance, ran with a less plantarflexed and more adducted forefoot and a more abducted hallux; and at push-off, ran with a less dorsiflexed midfoot and a less adducted and more dorsiflexed hallux. The IG runners also had significantly decreased medial longitudinal arch excursion (p = 0.024) and increased rearfoot inversion (p = 0.037). The 8-week foot-core exercise program had no effect on impact (p = 0.129) and breaking forces (p = 0.934) or on vertical loading rate (p = 0.537), but it was positively effective in changing foot-ankle kinematic patterns."

Predictive Effect of Well-Known Risk Factors and Foot-Core Training in Lower Limb Running-Related Injuries in Recreational Runners: A Secondary Analysis of a Randomized Controlled Trial.

BACKGROUND: Running carries the risk of several types of running-related injuries (RRIs), especially in the lower limbs. The variety of risk factors and the lack of strong evidence for several of these injury risks hinder the ability to draw assertive conclusions about them, hampering the implementation of effective preventive strategies. Because the etiology of RRIs seems to be multifactorial, the presence of RRI risk factors might influence the outcome of therapeutic strategies in different ways. Thus, further investigations on how risk and protective factors influence the incidence and prevention of RRIs should be conducted. PURPOSE: To investigate the predictive effect of well-known risk factors and 1 protective factor-foot-core training-on the incidence of lower limb RRIs in recreational runners. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Middle- and long-distance recreational runners (N = 118) were assessed at baseline and randomly allocated to either an intervention group (n = 57) or a control group (n = 61). The intervention group underwent an 8-week (3 times/wk) foot-core training program. Participants were followed for a year after baseline assessment for the occurrence of RRIs. Logistic regression with backward elimination of variables was used to develop a model for prediction of RRI in recreational runners. Candidate predictor variables included age, sex, body mass index, years of running practice, number of races, training volume, training frequency, previous RRI, and the foot-core exercise training. RESULTS: The final logistic regression model included 3 variables. As previously shown, the foot-core exercise program is a protective factor for RRIs (odds ratio, 0.40; 95% CI, 0.15-0.98). In addition, older age (odds ratio, 1.07; 95% CI, 1.00-1.14) and higher training volume (odds ratio, 1.02; 95% CI, 1.00-1.03) were risk factors for RRIs. CONCLUSION: The foot-core training was identified as a protective effect against lower limb RRI, which can be negatively influenced by older age and higher weekly training volume. The predictive model showed that RRIs should be considered a multivariate entity owing to the interaction among several factors. REGISTRATION: NCT02306148 (ClinicalTrials.gov identifier).

Accuracy and correlation between skin-marker based and radiographic measurements of medial longitudinal arch deformation.

Static and dynamic measurements of the medial longitudinal arch (MLA) in the foot are critical across different clinical and biomechanical research fields. While MLA deformation can be estimated using skin-markers for gait analysis, the current understanding of the correlates between skin-marker based models and radiographic measures of the MLA is limited. This study aimed at assessing the correlation and accuracy of skin-marker based measures of MLA deformation with respect to standard clinical X-ray based measures, used as reference. 20 asymptomatic subjects without morphological alterations of the foot volunteered in the study. A lateral X-ray of the right foot of each subject was taken in monopodalic upright posture with and without a metatarsophalangeal-joint dorsiflexing wedge. MLA angle was estimated in the two foot postures and during gait using 16 skin-marker based models, which were established according to the marker set of a validated multi-segment foot kinematic protocol. The error of each model in tracking MLA deformation was assessed and correlated with respect to standard radiographic measurements. Estimation of MLA deformation was highly affected by the skin-marker models. Skin-marker models using the marker on the navicular tuberosity as apex of the MLA angle showed the smallest errors (about 2 deg) and the largest correlations (R = 0.64-0.65; p < 0.05) with respect to the radiographic measurements. According to the outcome of this study, skin-marker based definitions of the MLA angle using the navicular tuberosity as apex of the arch may provide a more accurate estimation of MLA deformation with respect to that from radiographic measures.

Subgroups of Foot-Ankle Movement Patterns Can Influence the Responsiveness to a Foot-Core Exercise Program: A Hierarchical Cluster Analysis.

The purpose of this study is to identify homogenous subgroups of foot-ankle (FA) kinematic patterns among recreational runners and further investigate whether differences in baseline movement patterns can influence the mechanical responses to a foot-core exercise intervention program. This is a secondary analysis of data from 85 participants of a randomized controlled trial (clinicaltrials.gov - NCT02306148) investigating the effects of an exercise-based therapeutic approach focused on FA complex. A validated skin marker-based multi-segment foot model was used to acquire kinematic data during the stance phase of treadmill running. Kinematic features were extracted from the time-series data using a principal component analysis, and the reduced data served as input for a hierarchical cluster analysis to identify subgroups of FA movement patterns. FA angle time series were compared between identified clusters and the mechanical effects of the foot-core exercise intervention was assessed for each subgroup. Two clusters of FA running patterns were identified, with cluster 1 (n = 36) presenting a pattern of forefoot abduction, while cluster 2 (n = 49) displayed deviations in the proximal segments, with a rearfoot adduction and midfoot abduction throughout the stance phase of running. Data from 29 runners who completed the intervention protocol were analyzed after 8-weeks of foot-core exercises, resulting in changes mainly in cluster 1 (n = 16) in the transverse plane, in which we observed a reduction in the forefoot abduction, an increase in the rearfoot adduction and an approximation of their pattern to the runners in cluster 2 (n = 13). The findings of this study may help guide individual-centered treatment strategies, taking into account their initial mechanical patterns.

Foot Core Training to Prevent Running-Related Injuries: A Survival Analysis of a Single-Blind, Randomized Controlled Trial.

BACKGROUND: Running-related injuries (RRIs) are a pervasive menace that can interrupt or end the participation of recreational runners in this healthy physical activity. To date, no satisfactory treatment has been developed to prevent RRIs. PURPOSE: To investigate the efficacy of a novel foot core strengthening protocol based on a ground-up approach to reduce the incidence of RRIs in recreational long-distance runners over the course of a 1-year follow-up. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: The participants, 118 runners, were assessed at baseline and randomly allocated to either an intervention group (n = 57) or a control group (n = 61). The intervention group received an 8-week training course focused on the foot-ankle muscles, followed by remotely supervised training thereafter. Assessments consisted of 3 separate biomechanical evaluations of foot strength and foot posture and a weekly report on each participant's running distance, pace, and injury incidence over 12 months. RESULTS: The control group participants were 2.42 times (95% CI, 1.98-3.62) more likely to experience an RRI within the 12-month study period than participants in the intervention group (P = .035). Time to injury was significantly correlated with Foot Posture Index (P = .031; r = 0.41) and foot strength gain (P = .044; r = 0.45) scores. This foot exercise program showed evidence of effective RRI risk reduction in recreational runners at 4 to 8 months of training. CONCLUSION: Recreational runners randomized to the new foot core strengthening protocol had a 2.42-fold lower rate of RRIs compared with the control group. Further studies are recommended to better understand the underlying biomechanical mechanisms of injury, types of injuries, and subgroups of runners who might benefit maximally. REGISTRATION: NCT02306148 (ClinicalTrials.gov identifier).

Effects of a foot-ankle strengthening programme on clinical aspects and gait biomechanics in people with knee osteoarthritis: protocol for a randomised controlled trial.

INTRODUCTION: Studies have indicated that hip and knee muscle strengthening are effective in reducing pain, improving self-reported function and increasing lower limb strength, without, however, decreasing knee joint overload during gait in patients with knee osteoarthritis (KOA). Recent research has shown that strengthening the foot-ankle muscles improved function in diabetic patients and reduced patellofemoral pain. The aim of this paper is to investigate whether an 8-week therapeutic foot-ankle exercise programme improves pain, functionality, foot strength, foot kinematics and knee joint overload during gait, and decreases medication intake in individuals with KOA. METHODS AND ANALYSIS: This two-arm, prospectively registered, randomised controlled trial with blinded assessors will involve 88 patients with medial tibiofemoral osteoarthritis. Subjects will be randomly allocated to a control group that will receive no specific foot intervention and will follow treatment recommended by the medical team; or an intervention group that will undergo an 8-week physiotherapist-supervised strengthening programme for extrinsic and intrinsic foot muscles, three times a week. The primary outcome will be the pain domain of the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC). The secondary outcomes include WOMAC stiffness and function domains, total WOMAC score, physical function, foot muscle isometric strength, foot kinematics and knee kinetics during gait, and medication intake. Data will be analysed on intention-to-treat principles and a per protocol basis. ETHICS AND DISSEMINATION: Investigators and sponsors will communicate trial results to participants and healthcare professionals through scientific databases and social media. In addition, findings will be reported in peer-review publications, and at national and international conference presentations. Ethics approval: Ethics Committee of the Universidade Federal de São Carlos, São Carlos, SP, Brazil (N° 3.488.466). TRIAL REGISTRATION NUMBER: NCT04154059.

Repeatability of skin-markers based kinematic measures from a multi-segment foot model in walking and running.

Skin-markers based multi-segment models are growing in popularity to assess foot joint kinematics in different motor tasks. However, scarce is the current knowledge of the effect of high-energy motor tasks, such as running, on the repeatability of these measurements. This study aimed at assessing and comparing the inter-trial, inter-session, and inter-examiner repeatability of skin-markers based foot kinematic measures in walking and running in healthy adults. The repeatability of 24 kinematic measures from an established multi-segment foot model were assessed in two volunteers during multiple barefoot walking and running trials by four examiners in three sessions. Statistical Parametric Mapping (1D-SPM) analysis was performed to assess the degree of shape-similarity between patterns of kinematic measurements. The average inter-trial variability across measurements (deg) was 1.0 ± 0.3 and 0.8 ± 0.3, the inter-session was 3.9 ± 1.4 and 4.4 ± 1.5, and the inter-examiner was 5.4 ± 2.3 and 5.7 ± 2.2, respectively in walking and running. Inter-session variability was generally similar between the two motor tasks, but significantly larger in running for two kinematic measures (p < 0.01). Inter-examiner variability was generally larger than inter-trial and inter-session variability. While no significant differences in frame-by-frame offset variability was detected in foot kinematics between walking and running, 1D-SPM revealed that the shape of kinematic measurements was significantly affected by the motor task, with running being less repeatable than walking. Although confirmation on a larger population and with different kinematic protocols should be sought, attention should be paid in the interpretation of skin-markers based kinematics in running across sessions or involving multiple examiners.

Effects of a foot strengthening program on foot muscle morphology and running mechanics: A proof-of-concept, single-blind randomized controlled trial.

OBJECTIVES: To investigate the effects of a foot training program on muscle morphology and strength as well as running biomechanics in healthy recreational runners. DESIGN: Proof-of-concept, single-blind randomized controlled trial. SETTINGS: Runners were allocated to a control (CG) or an intervention (IG) group. The intervention focused on strengthening the intrinsic foot muscles and their activation during weight-bearing activities. All participants were assessed at baseline and after 8-weeks. PARTICIPANTS: Twenty-eight healthy recreational long-distance runners not habituated to minimalist running shoes or barefoot running. MAIN OUTCOMES MEASURES: Outcomes were hallux and toes strength; foot function, cross-sectional area and volume of the abductor hallucis (ABH), abductor digiti minimi (ABV), flexor digitorum brevis (FDB), and flexor hallucis brevis; medial longitudinal arch range of motion and stiffness; vertical and antero-posterior propulsive impulses during running. RESULTS: Compared to the CG, an increase was found in the IG for the volume of all muscles investigated and for vertical propulsive impulse during running. Correlations were found between vertical propulsive impulse and volume of ABH(r = 0.40), ABV(r = 0.41), and FDB(r = 0.69). CONCLUSION: The foot exercise protocol effectively increased intrinsic foot muscle volume and propulsive forces in recreational runners. This shows that intrinsic muscle strengthening affects running mechanics and suggests that it may improve running performance.

Reliability of medial-longitudinal-arch measures for skin-markers based kinematic analysis.

The medial-longitudinal arch (MLA) is perhaps the most important feature characterizing foot morphology. While current skin-markers based models of the MLA angle used in stereophotogrammetry allow to estimate foot arch shape and deformation, these do not always appear consistent with foot anatomy and with standard clinical definitions. The aim of this study was to propose novel skin-markers based measures of MLA angle and investigate their reliability during common motor tasks. Markers on the calcaneus, navicular tuberosity, first metatarsal head and base, and on the two malleoli were exploited to test eight definitions of MLA angle consistent with foot anatomy, both as angles between two 3-dimensional vectors and as corresponding projections on the sagittal plane of the foot. The inter-trial, inter-session and inter-examiner reliability of each definition was assessed in multiple walking and running trials of two volunteers, tested by four examiners in three sessions. Inter-trial variability in walking was in the range 0.7-1.2 deg, the inter-session 2.8-7.5 deg, and the inter-examiner in the range 3.7-9.3 deg across all MLA definitions. The Rizzoli Foot Model definition showed the lowest inter-session and inter-examiner variability. MLA measures presented similar variability in walking and running. This study provides preliminary information on the reliability of MLA measurements based on skin-markers. According to the present study, angles between 3-dimensional vectors and minimal marker sets should be preferred over sagittal-plane projections. Further studies should be sought to investigate which definition is more accurate with respect to the real MLA deformation in different loading conditions.

Effects of a therapeutic foot exercise program on injury incidence, foot functionality and biomechanics in long-distance runners: Feasibility study for a randomized controlled trial.

BACKGROUND: The goal was to examine the feasibility of a randomized controlled trial (RCT) on the effect of a therapeutic foot-ankle training program to prevent injury in long-distance runners. First, we evaluated (i) the access to participants and recruitment success; (ii) participants' satisfaction and adherence to the program; (iii) the effect of the training program to improve foot muscle strength and change foot biomechanics; and, second, we used the collected data for a post hoc sample size calculation. METHODS/DESIGN: We randomized 31 healthy long-distance recreational runners to either an 8-week foot-ankle muscle strength-training program (intervention) or a stretching protocol (control). The recruitment rate was the number of eligible participants per week of recruitment; recruitment success, the ratio between scheduled baseline visits and initially eligible participants. Participant satisfaction was assessed by a questionnaire, and adherence to the training program was recorded in a Web-based software, both at the 8-week mark. Program effect was assessed by hallux and toe muscle strength using a pressure platform, foot muscle cross-sectional area using magnetic resonance imaging and foot kinematics during running using 3D gait analysis; assessments were done at baseline and after 8 and 16 weeks. A post hoc power analysis was performed on foot strength and the biomechanical data was collected. RESULTS: In two weeks of recruitment, 112 initially eligible subjects were screened, 81 of whom were deemed eligible and 31 had a baseline study visit, giving a recruitment rate of 40.5 subjects/week and recruitment success of 28%. Participants' adherence was 97%, and satisfaction scored a median >3 out of 5 on a Likert scale on all questions. The cross-sectional area of the abductor hallucis (P = 0.040) and flexor digitorum brevis (P = 0.045) increased significantly at 8 weeks in the intervention group. The post hoc sample sizes for almost all the strength and biomechanical parameters were below those of the 112 subjects calculated as the original sample size for clinical outcome (running-related injury). CONCLUSION: Results show that this RCT is feasible, given an accessible study population that is willing to participate and that perceives the training program as positive and adheres to the program. The training program leads to several positive outcomes on muscle strength that justifies assessing clinical outcomes in this RCT.

Protocol for evaluating the effects of a therapeutic foot exercise program on injury incidence, foot functionality and biomechanics in long-distance runners: a randomized controlled trial.

BACKGROUND: Overall performance, particularly in a very popular sports activity such as running, is typically influenced by the status of the musculoskeletal system and the level of training and conditioning of the biological structures. Any change in the musculoskeletal system's biomechanics, especially in the feet and ankles, will strongly influence the biomechanics of runners, possibly predisposing them to injuries. A thorough understanding of the effects of a therapeutic approach focused on feet biomechanics, on strength and functionality of lower limb muscles will contribute to the adoption of more effective therapeutic and preventive strategies for runners. METHODS/DESIGN: A randomized, prospective controlled and parallel trial with blind assessment is designed to study the effects of a "ground-up" therapeutic approach focused on the foot-ankle complex as it relates to the incidence of running-related injuries in the lower limbs. One hundred and eleven (111) healthy long-distance runners will be randomly assigned to either a control (CG) or intervention (IG) group. IG runners will participate in a therapeutic exercise protocol for the foot-ankle for 8 weeks, with 1 directly supervised session and 3 remotely supervised sessions per week. After the 8-week period, IG runners will keep exercising for the remaining 10 months of the study, supervised only by web-enabled software three times a week. At baseline, 2 months, 4 months and 12 months, all runners will be assessed for running-related injuries (primary outcome), time for the occurrence of the first injury, foot health and functionality, muscle trophism, intrinsic foot muscle strength, dynamic foot arch strain and lower-limb biomechanics during walking and running (secondary outcomes). DISCUSSION: This is the first randomized clinical trial protocol to assess the effect of an exercise protocol that was designed specifically for the foot-and-ankle complex on running-related injuries to the lower limbs of long-distance runners. We intend to show that the proposed protocol is an innovative and effective approach to decreasing the incidence of injuries. We also expect a lengthening in the time of occurrence of the first injury, an improvement in foot function, an increase in foot muscle mass and strength and beneficial biomechanical changes while running and walking after a year of exercising. TRIAL REGISTRATION: Clinicaltrials.gov Identifier NCT02306148 (November 28, 2014) under the name "Effects of Foot Strengthening on the Prevalence of Injuries in Long Distance Runners". Committee of Ethics in Research of the School of Medicine of the University of Sao Paulo (18/03/2015, Protocol # 031/15).

Long-term use of minimal footwear on pain, self-reported function, analgesic intake, and joint loading in elderly women with knee osteoarthritis: A randomized controlled trial.

BACKGROUND: Efforts have been made to retard the progressive debilitating pain and joint dysfunction in patients with knee osteoarthritis. We aimed to evaluate the therapeutic effect of a low-cost minimalist footwear on pain, function, clinical and gait-biomechanical aspects of elderly women with knee osteoarthritis. METHODS: Throughout a randomized, parallel and controlled clinical trial, fifty-six patients with medial knee osteoarthritis were randomly allocated to an intervention (n=28) or control group (n=28), and assessed at baseline and after three and six months. The intervention involved wearing Moleca(®) footwear for at least 6h/day, 7 days/week, over 6 months. The pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index was the primary outcome. The secondary outcomes were the other subscales, Lequesne score, distance walked in 6 min, knee oedema and effusion, knee adduction moment and paracetamol intake. Intention-to-treat analysis was performed using two-way casewise ANOVA (< .05) and Cohen's d coefficient. FINDINGS: Intervention group showed improvement in pain (effect size: 1.41, p<.001), function (effect size: 1.22, p=.001), stiffness (effect size: 0.76, p=.001), Lequesne score (effect size: 1.07, p<.001), and reduction by 21.8% in the knee adduction moment impulse (p=.017) during gait wearing Moleca(®). The analgesic intake was lower in the intervention group. INTERPRETATION: The long-term use of Moleca(®) footwear relieves pain, improves self-reported function, reduces the knee loading while wearing Moleca(®), refrains the increase of analgesic intake in elderly women with knee osteoarthritis and can be considered as a conservative mechanical treatment option. ClinicalTrials.gov (NCT01342458).

Effect of a rocker non-heeled shoe on EMG and ground reaction forces during gait without previous training.

Unstable shoes have been designed to promote "natural instability" and during walking they should simulate barefoot gait, enhancing muscle activity and, thus, attributing an advantage over regular tennis shoes. Recent studies showed that, after special training on the appropriate walking pattern, the use of the Masai Barefoot Technology (MBT) shoe increases muscle activation during walking. Our study presents a comparison of muscle activity as well as horizontal and vertical forces during gait with the MBT, a standard tennis shoe and barefoot walking of healthy individuals without previous training. These variables were compared in 25 female subjects and gait conditions were compared using ANOVA repeated measures (effect size:0.25). Walking with the MBT shoe in this non-instructed condition produced higher vertical forces (first vertical peak and weight acceptance rate) than walking with a standard shoe or walking barefoot, which suggests an increase in the loads received by the musculoskeletal system, especially at heel strike. Walking with the MBT shoe did not increase muscle activity when compared to walking with the standard shoe. The barefoot condition was more effective than the MBT shoe at enhancing muscle activation. Therefore, in healthy individuals, no advantage was found in using the MBT over a standard tennis shoe without a special training period. Further studies using the MBT without any instruction over a longer period are needed to evaluate if the higher loads observed in the present study would return to their baseline values after a period of adaptation, and if the muscle activity would increase over time.