The Midfoot Joint Complex (Foot Arch) Contributes to the Upper Body Position in Bipedal Walking and Coordinates With the Lower Limb Joints.

This study estimated the contribution of the midfoot joint complex (MJC) kinematics to the pelvis anterior-posterior positions during the stance phase of walking and investigated whether the MJC is functionally coordinated with the lower limb joints to maintain similar pelvic positions across steps. Hip, knee, ankle, and MJC sagittal angles were measured in 11 nondisabled participants during walking. The joints' contributions to pelvic positions were computed through equations derived from a link-segment model. Functional coordination across steps was identified when the MJC contribution to pelvic position varied and the summed contributions of other joints varied in the opposite direction (strong negative covariations [r ≤ -.7] in stance phase instants). We observed that the MJC plantarflexion (arch raising) during the midstance and late stance leads the pelvis backward, avoiding excessive forward displacement. The MJC was the second joint that contributed most to the pelvis positions (around 18% of all joints' contributions), after the ankle joint. The MJC and ankle were the joints that were most frequently coordinated with the other joints (≅70% of the stance phase duration). The findings suggest that the MJC is part of the kinematic chain that determines pelvis positions during walking and is functionally coordinated with the lower limb joints.

Influence of reduced passive ankle dorsiflexion range of motion on lower limb kinetics and stiffness during gait.

BACKGROUND: The ankle dorsiflexion range of motion (ADF-ROM) during single support phase allows elastic energy storage in the calcaneal tendon, contributing to advance the body forward. Reduced ADF-ROM may influence lower limb kinetics and stiffness. RESEARCH QUESTION: What is the influence of reduced passive ADF-ROM on lower limb internal moments and stiffness during gait? METHODS: Thirty-two participants, classified into two groups according to passive ADF-ROM (smaller than 10° and greater than 15°), were submitted to gait assessment at self-selected speed with a force platform and a three-dimensional motion analysis system. Statistical parametrical mapping (SPM) analyses were used to compare the lower limbs' internal moments between groups. Independent t-tests analyzed the differences between groups on lower limb stiffness during gait. RESULTS: The lower ADF-ROM group had greater knee flexor moment (terminal stance and push-off), greater ankle abductor (i.e., shank internal rotator) moment in terminal stance and greater knee internal rotator moment in mid to terminal stance. The lower ADF-ROM group also had higher lower limb stiffness during gait. SIGNIFICANCE: Individuals with reduced passive ADF-ROM had greater lower limb stiffness and adopted a gait pattern with increased knee and ankle moments, suggesting increased loading at these joints.

Performance in field-tests and dynamic knee valgus in soccer players psychologically ready and not ready to return to sports after ACL reconstruction.

BACKGROUND: The objective was to compare the performance in field tests, dynamic knee valgus, knee function, and kinesiophobia of soccer players who were psychologically ready and not ready to return to unrestricted training or competitions after ACL reconstruction. METHODS: Thirty-five male soccer players who had undergone primary ACL reconstruction at least 6 months were divided based on the Anterior Cruciate Ligament Return to Sport after Injury (ACL-RSI) questionnaire score into ready (≥60) and not-ready (<60) groups. The modified Illinois change of direction test (MICODT) and reactive agility test (RAT) were used to impose the demand for directional change and reactive decision-making. We assessed the frontal plane knee projection angle (FPKPA) during a single-leg squat and distance in crossover hop test (CHD). In addition, we assessed kinesiophobia through the shortened version of the Tampa Scale of Kinesiophobia (TSK-11) and knee function using the International Knee Documentation Committee Subjective Knee Form (IKDC). Independent t-tests were used to compare the groups. RESULTS: The not-ready group had lower performance on the MICODT (effect size (ES) = -1.2; p < 0.001) and RAT (ES = -1.1; p = 0.004) tests and higher FPKPA (ES = 1.5; p < 0.001). In addition, they presented lower IKDC (ES = 3.1; p < 0.001) and higher TSK-11 (ES = -3.3; p < 0.001) scores. CONCLUSIONS: Physical and psychological deficits may persist in some individuals after rehabilitation. On-field tests and dynamic knee alignment evaluation should be included in the athlete evaluation before the decision-making about clearance to sports participation, especially in athletes who perceive themselves as psychologically not ready.

A new marker cluster anchored to the iliotibial band improves tracking of hip and thigh axial rotations.

Tracking hip and thigh axial rotation has limited accuracy due to the large soft tissue artifact. We proposed a tracking-markers cluster anchored to the prominent distal part of the iliotibial band (ITB) to improve thigh tracking. We investigated if the ITB cluster improves accuracy compared with a traditionally used thigh cluster. We also compared the hip kinematics obtained with these clusters during walking and step-down. Hip and thigh kinematics were assessed during a task of active internal-external rotation with the knee extended, in which the shank rotation is a reference due to smaller soft-tissue artifact. Errors of the hip and thigh axial rotations obtained with the thigh clusters compared to the shank cluster were computed as root-mean-square errors, which were compared by paired t-tests. The angular waveforms of this task were compared using the statistical parametric mapping (SPM). Additionally, the hip waveforms in all planes obtained with the thigh clusters were compared during walking and step-down, using Coefficients of Multiple Correlation (CMC) and SPM (α = 0.05 for all analyses). The ITB cluster errors were approximately 25 % smaller than the traditional cluster error (p < 0.001). ITB cluster errors were smaller at external rotation angles while the traditional cluster error was smaller at internal rotation angles (p < 0.001), although the clusters' waveforms were not significantly different (p ≥ 0.005). During walking and step-down, both clusters provided similar hip kinematics (CMC ≥ 0.75), but differences were observed in parts of the cycles (p ≤ 0.04). The findings suggest that the ITB cluster may be used in studies focused on hip axial rotation.

Association of Cycling Kinematics With Anterior Knee Pain in Mountain Bike Cyclists.

CONTEXT: Comfort and pain in cyclists are often discussed as a result of the posture on the bike, and bike fit, including motion analysis, is advocated as a strategy to minimize these conditions. The relationship between cycling kinematics, comfort, and pain is still debatable. OBJECTIVES: To investigate the association of ankle, knee, and trunk kinematics with the occurrence of anterior knee pain (AKP) in mountain bike cyclists. DESIGN: Cross-sectional study. METHODS: Fifty cross-country mountain bike cyclists (26 with AKP and 24 without AKP) had their pedaling kinematics assessed. Linear and angular data from trunk, hip, knee, ankle, and foot from cyclists with and without AKP were recorded using Retül motion analysis system. RESULTS: The binary logistic regression model showed that kinematic variables such as peak ankle plantar flexion, peak knee flexion, and forward trunk lean were significant predictors of AKP. Both larger peak plantar flexion and knee flexion decreased the probability of reporting AKP. On the other hand, larger forward trunk lean increased the probability of reporting AKP. CONCLUSIONS: Ankle, knee, and trunk sagittal kinematics may predict AKP in cross-country mountain bike cyclists, whereas hip, knee, and ankle alignment in the frontal plane showed no association with occurrence of AKP. In other words, cyclists with larger ankle plantar flexion and knee flexion are less likely to have AKP, whereas those with increased trunk forward lean are more likely to have AKP.

The Sleep Parameters of Paralympic Athletes: Characteristics and Assessment Instruments.

CONTEXT: Sleep serves many important functions for athletes, particularly in the processes of learning, memory, recovery, and cognition. OBJECTIVES: Define the sleep parameters of Paralympic athletes and identify the instruments used to assess and monitor sleep Paralympic athletes. EVIDENCE ACQUISITION: This systematic review was carried out based on the PRISMA guidelines. The survey was conducted in April 2020, the searches were carried out again in September 2021 to check whether there were new scientific publications in the area of sleep and Paralympic sport, searches were performed in the following databases: PubMed, Web of Science, Scopus, SPORTDiscus, Virtual Health Library (BIREME), and SciELO. This systematic review has included studies that investigated at least one of the following sleep parameters: total sleep time, sleep latency, sleep efficiency, number of awakenings, quality of sleep, daytime sleepiness, and chronotype; the participants were comprised of athletes with disabilities. Studies published at any time in English, Portuguese, and Spanish, were included. EVIDENCE SYNTHESIS: Data extraction and study selection were performed by 2 researchers independently, and a third author was consulted as necessary. The search returned a total of 407 studies. Following the screening based on exclusion and inclusion criteria, a total of 13 studies were considered. Paralympic athletes have a low amount (7.06 h) of sleep with poor quality and sleep latency (28.05 min), and 57.2% have daytime sleepiness, with the majority belonging to the indifferent chronotype (53, 5%). Moreover, 11 studies assess sleep using subjective instruments (questionnaires), and 2 studies used an objective instrument (actigraphy). CONCLUSIONS: Sleep disorders are common among Paralympic athletes, poor sleep quality and quantity, and high rates of daytime sleepiness. Subjective methods are most commonly used to assess sleep.

Effectiveness of multimodal circuit exercises for chronic musculoskeletal pain in older adults: A randomized controlled trial protocol.

Studies have shown that musculoskeletal pain is one of the most prevalent health conditions that affects many individuals worldwide. In older adults, persistent pain is a widely prevalent and a disabling condition of multiple contributing factors: physical, mental, and social. Consequently, their quality of life is hampered. We aimed to analyze the effectiveness of a multimodal circuit exercise program on chronic musculoskeletal pain and disabling in older adults. This is a randomized parallel study (two arms) with blinded outcome assessments. The participants' recruitment will be done by a non-probabilistic sampling resulting from invitations to Basic Health Units (BHU). The sample size estimation indicated 164 participants. Participants will be allocated, by means of a randomization process, to one of two groups (82 for each group): Experimental Group (multimodal circuit exercise) or Control Group (cycle of multidisciplinary lectures on pain and stretching exercise). All analyses will be processed using the RStudio software, with significance when a p-value of 2 tails is less than 5% (p<0.05). Statistical analysis will follow the intention to treat. Trial registration: ClinicalTrials.gov NCT04719130, January 20, 2021.

Comparison between the Rizzoli and Oxford foot models with independent and clustered tracking markers.

BACKGROUND: The Rizzoli Foot Model (RFM) and Oxford Foot Model (OFM) are used to analyze segmented foot kinematics with independent tracking markers. Alternatively, rigid marker clusters can be used to improve markers' visualization and facilitate analyzing shod gait. RESEARCH QUESTION: Are there differences in angles from the RFM and OFM, obtained with independent and clustered tracking markers, during the stance phase of walking? METHODS: Walking kinematics of 14 non-disabled participants (25.2 years (SD 2.8)) were measured at self-selected speed. Rearfoot-shank and forefoot-rearfoot angles were measured from two models with two tracking methods: RFM, OFM, RFM-cluster, and OFM-cluster. In RFM-cluster and OFM-cluster, the rearfoot and forefoot tracking markers were rigidly clustered, fixed on rods' tips attached to a metallic base. Statistical Parametric Mapping (SPM) One-Way Repeated Measures ANOVAs and SPM Paired t-tests were used to compare waveforms. Coefficients of Multiple Correlation (CMC) quantified the similarity between waveforms. One-way Repeated Measures ANOVAs were conducted to compare the ranges of motion (ROMs), and pre-planned contrasts investigated differences between the models and tracking methods. Intraclass Correlation Coefficients (ICC) were computed to verify the similarity between ROMs. RESULTS: Differences occurred mostly in small parts of the stance phase for the cluster vs. non-cluster comparisons and the RFM vs. OFM comparisons. ROMs were slightly different between the models and tracking methods in most comparisons. The curves (CMC ≥ 0.71) were highly similar between the models and tracking methods. The ROMs (ICC ≥ 0.67) were moderatetly to highly similar in most comparisons. RFM vs. RFM-cluster (forefoot-rearfoot angle - transverse plane), OFM vs. OFM-cluster and RFM vs. OFM (forefoot-rearfoot angle - frontal plane) were not similar (non-significant). SIGNIFICANCE: Rigid clusters are an alternative for tracking rearfoot-shank and forefoot-rearfoot angles during the stance phase of walking. However, specific differences should be considered to contrast results from different models and tracking methods.

Comparison of incidence, prevalence, severity and profile of health problems between male and female elite youth judokas: A 30-week prospective cohort study of 154 athletes.

OBJECTIVES: To describe and compare the incidence, prevalence, severity, and profile of injuries (acute and overuse) and illness between female and male youth elite judokas during 30 weeks of a sports season. DESIGN: Prospective cohort study. METHODS: A total of 154 elite youth judokas (83 males and 71 females) were assessed from January to August 2019 in a training period organized by the Brazilian Judo Confederation. We conducted a prospective 30-week follow-up study on acute and overuse injuries and illness among youth female and male judokas through the Oslo Sports Trauma Research Center questionnaire on health problems (OSTRC-H). Every week, the OSTRC-H was sent to all youth judokas electronically, starting in the first week of preseason. The incidence rate, prevalence, and severity of illnesses and acute and overuse injuries were compared between sexes using an independent t-test (variables with normal distribution) or Mann Whitney U test (variables with non-normal distribution) with α set a 0.05. RESULTS: Female and male judokas showed 16.96 and 16.57 injuries per 1000 athletic exposures, respectively (p = 0.383). Female judokas showed a higher average weekly prevalence of health problems (38.8%) than male judokas (29.0%). In addition, females had a greater prevalence of substantial health problems (p < 0.001), injuries (p < 0.001), and overuse injuries (p < 0.001) than males. CONCLUSION: There were no differences in the incidence rate of injuries between sexes. Youth female judokas showed a higher prevalence of all health problems than youth male judokas. For both sexes, the knee and shoulder were the most affected joints for acute and overuse injuries, respectively.

Prevalence of overuse injuries in athletes from individual and team sports: A systematic review with meta-analysis and GRADE recommendations.

BACKGROUND: Overuse injuries result from the cumulative process of repetitive microtrauma and overload on the musculoskeletal system, which causes tissue damage. Therefore, these injuries may have long-term negative consequences that decrease an athlete's performance. OBJECTIVE: To estimate the prevalence of overuse injuries in individual and team sports. METHODS: Searches on MEDLINE, EMBASE, SPORTDiscus, and CINAHL from the first registration to February 2021 and hand-searching identified studies investigating the prevalence of overuse injuries in athletes from individual and team sports. Meta-analysis was conducted and the GRADE system summarized the overall quality of evidence. This review was registered in PROSPERO (CRD42019135665). RESULTS: Seventeen studies were included and pooling of 24 704 participants (22 748 of individual sports and 1.956 of team sports). Data from point- and period-prevalence of overuse injuries in individual and team sports were obtained. Pooled period-prevalence of overuse injuries in individual and team sports was 42.0% (95% CI: 30.0, 55.0) and 33.0% (95% CI: 21.0, 49.0), respectively. Another four studies investigated point-prevalence. The overall quality of evidence for the period-prevalence was of moderate quality. Sensitivity analyses suggested that different joints based in individual and team sports tended to increase the estimated prevalence of overuse injuries. CONCLUSION: Athletes, clinicians, sport teams, and policymakers should be aware of the high prevalence of overuse injuries in athletes, especially, in athletes from individual sports. Current moderate-quality evidence shows that future high-quality studies are likely to impact on the estimated prevalence.

Spinal cord injury and work challenges: an analysis of paid work status and pathways of return to work in Brazil.

DESIGN: Retrospective cohort study. OBJECTIVES: To investigate paid work status and return to work (RTW) pathways after spinal cord injury (SCI). SETTING: SARAH Network of Rehabilitation Hospitals. METHODS: Participants were adults with traumatic SCI, aged between 18 and 60 years at the time of the injury, admitted between 2000 and 2017. In the first stage, socio-demographic, injury-related, and functional status data were collected from medical records. In the second stage, data on paid work, means of mobility, driving ability, return to study, ability to work, and satisfaction with the work status were collected through an online survey conducted between January and March 2020. RESULTS: A total of 154 participants were included in the sample. Of these, 90% were working at the time of SCI and 23% were engaged in paid work at the time of the study. Three RTW pathways were identified among those who were working at the time of the injury and: did not return to work (78%); returned to a different occupation (12%) and returned to the same occupation (9%). Number of post-injury complications, returning to study, good work ability, and satisfaction with the work status were predictors of paid work. The model's adjusted coefficient was 56.5% (p = 0.001). CONCLUSION: Working-age people with SCI who underwent rehabilitation in Brazil had a low rate of paid work. Fewer complications at the time of the injury, returning to study, good ability to work and greater satisfaction with the work status increased the likelihood of being engaged in paid work.

A novel single-leg squat test with speed and accuracy requirements: Reliability and validity in anterior cruciate ligament reconstructed individuals.

BACKGROUND: Some traditional single-leg squat tests focused on number of repetitions may not demand precise control of lower limb dynamic alignment, especially in the frontal and transverse planes. The primary objective of this study was to evaluate test-retest reliability and construct validity of a novel single-leg squat test - the 'precision-squat test' (PST) - designed to assess performance under varying task demands that can impact the execution of lower limb movements. A secondary objective was to investigate whether musculoskeletal factors predict performance in the PST in healthy individuals. METHODS: Thirty healthy participants were assessed to verify test-retest reliability. To verify the test's construct validity, we compared the performance of 21 anterior cruciate ligament reconstructed (ACLR) individuals and 21 matched controls. Finally, 36 healthy individuals were assessed to verify the musculoskeletal factors related to PST performance. All participants performed the PST: they executed single-leg squats while moving a laser pointer (attached to the thigh) between two targets. We varied target size and distance between targets to manipulate the task difficulty. RESULTS: Reliability of the PST was excellent at all demand levels (intraclass correlation coefficient (ICC)(3,2) > 0.93). Squat time increased under test conditions involving higher task difficulty (P < 0.001) and in ACLR individuals compared with age-matched controls (P < 0.05). Regression analyses revealed that reduced knee extensors and hip external rotators torques are related to increased squat time (P < 0.05). CONCLUSIONS: PST is a valid and reliable tool to assess performance of healthy and ACLR individuals. In addition, hip and knee strength are associated with performance during the test.

Reliability of a Low-Cost Assessment of Tibial Torsion and Transverse-Plane Posture of the Lower Limb and Pelvis Using a Smartphone Compass.

OBJECTIVES: The purpose of this study was to investigate intra- and interrater reliability and minimal detectable change (MDC) of clinical measures proposed to assess tibial torsion and the posture of the lower limbs and pelvis in the transverse plane. METHODS: Twenty-five able-bodied and asymptomatic participants (mean age 27 ± 4.03, 12 women) were assessed during relaxed standing with a compass application on a smartphone coupled to a caliper. Two trained examiners measured tibial torsion and angular postures of the pelvis, hip, femur, and tibia. Intraclass correlation coefficients (ICC) were used to investigate reliabilities, and MDCs were calculated. RESULTS: The results showed predominantly good-to-excellent reliability for the measures of the femur, hip, and tibia postures and tibial torsion (0.77 < ICC < 0.94), including some moderate-to-good reliability (0.65 < ICC < 0.75). The pelvic posture measure was predominantly moderate to good (0.55 < ICC < 0.86). MDCs have been reported (2.14°-7.86°) to assist clinicians in identifying postural changes that are within or outside the random measure variation. CONCLUSION: The use of a smartphone digital compass coupled to a caliper showed to be a reliable method to assess tibial torsion and transverse-plane postures of the lower limb and pelvis.

Normative reference values for handgrip strength, shoulder and ankle range of motion and upper-limb and lower limb stability for 137 youth judokas of both sexes.

OBJECTIVES: To provide reference values for handgrip strength, shoulder and ankle range of motion (ROM) and upper-limb and lower limb stability for youth judokas of both sexes and investigate the effects of sex and side dominance. DESIGN: Cross-sectional. METHODS: A total of 137 youth judokas from under-18 (n=60) and under-21 (n=77) categories of both sexes were assessed. Handgrip strength was assessed using a Jamar dynamometer, ankle ROM was measured by lunge test, shoulder ROM was assessed by an inclinometer and upper-limb and lower limb stability were assessed by the Closed Kinetic Chain Upper Extremity Stability Test and by the Modified Star Excursion Balance Test (mSEBT). RESULTS: In both categories, males had greater handgrip strength. In the under-18 category, the dominant side had greater handgrip strength, the non-dominant side of females had smaller shoulder external rotation ROM than the dominant side and also than both sides of males, and females had greater shoulder IR ROM. In the under-21 category, the dominant side of females had greater ankle dorsiflexion ROM than the dominant side of males, the dominant sides and females had greater shoulder ER ROM, and males had better performance in the mSEBT. CONCLUSIONS: This study provided reference values for handgrip strength, shoulder and ankle ROM, upper and lower limb stability for youth judokas, which can be used to guide assessment during preseason. Sex influenced on shoulder ER and IR ROM, handgrip strength and lower limb stability. In addition, side dominance influenced on shoulder ER ROM and on handgrip strength.

Sports Injury Forecasting and Complexity: A Synergetic Approach.

The understanding that sports injury is the result of the interaction among many factors and that specific profiles could increase the risk of the occurrence of a given injury was a significant step in establishing programs for injury prevention. However, injury forecasting is far from being attained. To be able to estimate future states of a complex system (forecasting), it is necessary to understand its nature and comply with the methods usually used to analyze such a system. In this sense, sports injury forecasting must implement the concepts and tools used to study the behavior of self-organizing systems, since it is by self-organizing that systems (i.e., athletes) evolve and adapt (or not) to a constantly changing environment. Instead of concentrating on the identification of factors related to the injury occurrence (i.e., risk factors), a complex systems approach looks for the high-order variables (order parameters) that describe the macroscopic dynamic behavior of the athlete. The time evolution of this order parameter informs on the state of the athlete and may warn about upcoming events, such as injury. In this article, we describe the fundamental concepts related to complexity based on physical principles of self-organization and the consequence of accepting sports injury as a complex phenomenon. In the end, we will present the four steps necessary to formulate a synergetics approach based on self-organization and phase transition to sports injuries. Future studies based on this experimental paradigm may help sports professionals to forecast sports injuries occurrence.

Prevalence of knee osteoarthritis in former athletes: a systematic review with meta-analysis.

BACKGROUND: Prevalence of knee osteoarthritis in former athletes is still unclear. OBJECTIVE: To investigate prevalence of knee osteoarthritis in former athletes. Moreover, the secondary aim was to investigate whether poor methodological quality of included studies, different diagnosis criteria for knee osteoarthritis, different sports modality or sex impact on overall estimated prevalence of knee osteoarthritis in former athletes. METHODS: Searches on MEDLINE, EMBASE, AMED, SPORTDiscus and CINAHL from the earliest record to February 2018 and hand-searching identified studies investigating prevalence of knee osteoarthritis in former athletes. Meta-analysis was conducted and the GRADE system summarized strength of the current recommendations. Sensitivity analyses investigated whether methodological quality, diagnostic criteria, type of sports or sex impacted on the overall estimated prevalence in former athletes. This review was registered at PROSPERO (CRD42016050903). RESULTS: Fifteen studies were included and pooling of 3100 participants estimated overall prevalence of knee osteoarthritis in former athletes of 30.0% (95% CI: 20.0 to 40.0%). The strength of the current recommendations was low-quality. Sensitivity analyses suggested that different diagnostic criteria for knee osteoarthritis and type of sports may impact on the overall estimated prevalence. CONCLUSIONS: Prevalence of knee osteoarthritis in former athletes was 30.0%. Researchers, clinicians and policymakers should be careful about potential prevalence differences among type of sports and diagnostic criteria. Current low-quality evidence shows that future high-quality studies are likely to impact on the estimated prevalence.

External rotation elastic bands at the lower limb decrease rearfoot eversion during walking: a preliminary proof of concept

ABSTRACT Background Reducing rearfoot eversion is a commonly desired effect in clinical practice to prevent or treat musculoskeletal dysfunction. Interventions that pull the lower limb into external rotation may reduce rearfoot eversion. Objective This study investigated whether the use of external rotation elastic bands, of different levels of stiffness, will decrease rearfoot eversion during walking. We hypothesized that the use of elastic bands would decrease rearfoot eversion and that the greater the band stiffness, the greater the eversion reduction. Method Seventeen healthy participants underwent three-dimensional kinematic analysis of the rearfoot and shank. The participants walked on a treadmill with and without high- and low-stiffness bands. Frontal-plane kinematics of the rearfoot-shank joint complex was obtained during the stance phase of walking. Repeated-measures ANOVAs were used to compare discrete variables that described rearfoot eversion-inversion: mean eversion-inversion; eversion peak; and eversion-inversion range of motion. Results The low-stiffness and high-stiffness bands significantly decreased eversion and increased mean eversion-inversion (p≤0.037) and eversion peak (p≤0.006) compared with the control condition. Both bands also decreased eversion-inversion range of motion (p≤0.047) compared with control by reducing eversion. The high-stiffness band condition was not significantly different from the low-stiffness band condition for any variables (p≥0.479). Conclusion The results indicated that the external rotation bands decreased rearfoot eversion during walking. This constitutes preliminary experimental evidence suggesting that increasing external rotation moments at the lower limb may reduce rearfoot eversion, which needs further testing.

External rotation elastic bands at the lower limb decrease rearfoot eversion during walking: a preliminary proof of concept.

Background: Reducing rearfoot eversion is a commonly desired effect in clinical practice to prevent or treat musculoskeletal dysfunction. Interventions that pull the lower limb into external rotation may reduce rearfoot eversion. Objective: This study investigated whether the use of external rotation elastic bands, of different levels of stiffness, will decrease rearfoot eversion during walking. We hypothesized that the use of elastic bands would decrease rearfoot eversion and that the greater the band stiffness, the greater the eversion reduction. Method: Seventeen healthy participants underwent three-dimensional kinematic analysis of the rearfoot and shank. The participants walked on a treadmill with and without high- and low-stiffness bands. Frontal-plane kinematics of the rearfoot-shank joint complex was obtained during the stance phase of walking. Repeated-measures ANOVAs were used to compare discrete variables that described rearfoot eversion-inversion: mean eversion-inversion; eversion peak; and eversion-inversion range of motion. Results: The low-stiffness and high-stiffness bands significantly decreased eversion and increased mean eversion-inversion (p≤0.037) and eversion peak (p≤0.006) compared with the control condition. Both bands also decreased eversion-inversion range of motion (p≤0.047) compared with control by reducing eversion. The high-stiffness band condition was not significantly different from the low-stiffness band condition for any variables (p≥0.479). Conclusion: The results indicated that the external rotation bands decreased rearfoot eversion during walking. This constitutes preliminary experimental evidence suggesting that increasing external rotation moments at the lower limb may reduce rearfoot eversion, which needs further testing.

Forefoot midsole stiffness affects forefoot and rearfoot kinematics during the stance phase of gait.

BACKGROUND: The forefoot midsole stiffness of the shoe may affect the kinematics of the foot segments. We evaluated the effects of two different levels of forefoot midsole stiffness on the angular displacement of the forefoot and rearfoot in the three planes of motion during the stance phase of gait. METHODS: Thirty-six participants walked on a 10-m walkway at their self-selected speed wearing shoes having either low or high forefoot midsole stiffness. Three-dimensional kinematic data of the foot segments were obtained during the stance phase of gait using an eight-camera motion analysis system synchronized with a force platform. The dependent variables were forefoot and rearfoot total range of motion and maximum and minimum angle values in the sagittal, frontal, and transverse planes of motion. RESULTS: Reduced forefoot midsole stiffness produced significantly greater forefoot total range of motion in the sagittal plane (1.59°). The low-stiffness condition also increased the magnitude of the forefoot dorsiflexion angles (4.14°). Furthermore, the low-stiffness condition increased the magnitude of the rearfoot inversion (1.21°) and adduction (11.38°) angles and reduced the rearfoot abduction angle (12.1°). CONCLUSIONS: It is likely that reduced stiffness of the forefoot midsole stretched the plantar fascia, increasing rearfoot stability during the stance phase of gait. Increased muscular contraction may also explain increases in rearfoot stability. Therefore, the integrity of the plantar fascia and ankle muscles' force and resistance should be considered when choosing a shoe with reduced or increased forefoot midsole stiffness for walking.

Application of principal component analysis on gait kinematics in elderly women with knee osteoarthritis.

BACKGROUND: The applicability of gait analysis has been implemented with the introduction of the principal component analysis (PCA), a statistical data reduction technique that allows the comparison of the whole cycle between groups of individuals. OBJECTIVES: Applying PCA, to compare the kinematics of the knee joint during gait, in the frontal and sagittal planes, between a group of elderly women with and without diagnosis in the initial and moderate stages of Osteoarthritis (OA). METHODS: A total of 38 elderly women (69.6±8.1 years) with knee OA and 40 asymptomatic (70.3±7.7 years) participated on this study. The kinematics was obtained using the Qualisys Pro-reflex system. RESULTS: The OA group showed decreased gait velocity and stride length (p<0.05) and was characterized with higher WOMAC pain score. In the frontal plane, the between-group differences of the components were not significant. In the sagittal plane, three principal components explained 99.7% of the data variance. Discriminant analysis indicated that component 2 and 3 could classify correctly 71.8% of the individuals. However, CP3, which captures the difference in the flexion knee angle magnitude during gait, was the variable with higher discrimination power between groups. CONCLUSIONS: PCA is an effective multivariate statistical technique to analyse the kinematic gait waveform during the gait cycle. The smaller knee flexion angle in the OA group was appointed as a discriminatory factor between groups, therefore, it should be considered in the physical therapy evaluation and treatment of elderly women with knee OA.