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Objective: To evaluate the effects of constraint-induced movement therapy on the use of the affected arm and on daily functioning in children with hemiplegic cerebral palsy. Design: A single-blinded randomized clinical trial. Subjects: Sixteen children with cerebral palsy randomized to intervention (n = 8, 4 males, 4 females, mean age 5 years and 6 months) and control groups (n = 8, 4 males, 4 females, mean age 6 years and 7 months). Interventions: Non-affected arm of intervention group was restricted for 10 hours/ day and the affected arm intensively trained for 3 hours/day for two weeks. The intervention protocol included one week of bimanual functional training following constraint therapy. The control group maintained usual rehabilitation throughout the intervention period. Main measures: Pediatric Evaluation of Disability Inventory (self-care domain) and an adapted version of the Jebsen-Taylor test were administered before and after intervention, and at one month follow-up. General linear models tested differences in gain scores and the number needed to treat estimated relative effectiveness of intervention protocol for functional skills and independence in self-care. Results: Results are reported for 15 children who completed assessments and intervention. Higher gains were observed in the intervention group for functional skills and independence post intervention (dfunctional skills = 1-61, P = 0.0134; dindependence = 1-37; P = 0.0001) and follow-up (dfunctional skills = 2.08, P = 0.004; dindependence = 0.85; P = 0.0016). No group difference in manual dexterity gains was observed. Low indices of number needed to treat (1.75 and 2.33) illustrate clinical relevance of intervention. Conclusions: The protocol associating constraint-induced movement therapy and bimanual functional training was effective in promoting daily living functioning among children with cerebral palsy. [ABSTRACT FROM AUTHOR]

Purpose. To investigate the psychometric properties (construct and discriminant validities) of the translated and validated version of DASH for the Portuguese language. Method. Methodological study included 309 subjects with chronic or acute upper limb injury divided into two groups: acute and chronic. The Factor Analysis (principal components) was carried out to examine the construct structure of the DASH and discriminant function to determine the items that best predict individuals classified into chronic and acute groups. Results. Group A presented a higher DASH score average (71.8, SD = 15.6); the average score for the overall sample was 52.6 (SD = 26.3). The Kaiser Meyer Olkin and Bartlett Test of Sphericity demonstrated satisfactory suitability of the data to factor analysis, which identified three factors with Cronbach alpha indices ranging between 0.77 and 0.94, explaining 59% of the variance in the overall sample. The discriminant analysis adequately classified 93% of the cases regarding the group of origin and identified 11 variables with a discriminating power between the acute and chronic groups. Conclusions. The DASH version adapted to Portuguese/Brazil proved to be a valid measure to document disability in the sample used for the present study. Specific items were identified as best predictors of chronic and acute group allocation. [ABSTRACT FROM AUTHOR]

Purpose. To investigate changes in hand function associated with electrical stimulation for children with hemiplegic cerebral palsy. Method. An ABCA single-subject design, replicated in two children, was used in this study. Each baseline (phase A) lasted 4 weeks. Intervention consisted of electrical stimulation of wrist extensors (phase B) and of wrist extensors and flexors (phase C) for 15 minutes three times a week. Intervention phases also lasted 4 weeks. Active wrist extension range of movement and three timed manual tasks were tested two times a week every week. Data analysis included the Celeration Line and Two Standard Deviation Band methods in addition to visual analysis. Results. Significant performance gains were observed for both children, especially in phase C, when both extensors and flexors were stimulated. After intervention withdrawal, significant performance decreases were observed on most analysed variables. Conclusions. The observed performance changes seem to be associated with the presence of intervention and suggest that electrical stimulation can be a useful adjunct to improve hand function of children with cerebral palsy. [ABSTRACT FROM AUTHOR]

This study compared the passive stiffness of wrist flexors and the strength of wrist flexors and extensors in three different wrist positions (30 degrees of flexion, neutral, and 30 degrees of extension) between children with cerebral palsy (CP) and typically developing (TD) comparison children. It also examined associations between these characteristics and manual function in children with CP. Eleven children with spastic hemiplegic CP (six females, five males; mean age 8y 5mo [SD 1y 8mo], range 6-11y) and 11 TD children, matched for age and sex, took part in this study. Passive stiffness of muscles was measured as the torque/angle relation during passive motion. Isometric strength tests were performed and the time needed to complete three tasks based on the Jebsen-Taylor Hand Function Test was recorded. Flexor stiffness was higher in the group with CP. Strength of flexors and extensors in the group with CP was lower with the wrist extended. No difference among test positions was found in the TD group. Moderate correlations were observed between manual function and variables related to strength and stiffness of wrist muscles in the group with CP. Children with CP showed muscle alterations coherent with the use of the wrist in flexion. Intervention on these characteristics could have a positive impact on manual function. [ABSTRACT FROM AUTHOR]

BACKGROUND: Botulinum toxin A (BTA) is commonly used to treat children with cerebral palsy (CP). However, the variables measured before BTA application and associated with motor function and independent mobility, known as predictors of functional outcomes, have not been well defined. OBJECTIVE: To identify clinical predictors of gains in functional motor skills and independence of mobility among children with CP, three and six months after BTA application. METHODS: This was a convenience sample of children with spastic CP (n=35). Measurements of quantitative gains in motor skills and independence of mobility were taken three and six months after BTA application. These outcomes were observed through repeated applications of two functional tests: GMFM (Gross Motor Function Measure) and PEDI (Pediatric Evaluation of Disability Inventory). These tests evaluated gross motor function while sitting or standing and during transitions between these postures, and also during dynamic activities such as walking, running and jumping, along with the children's independence in mobility tasks. The independent variables included the children's characteristics such as age, severity, topographic diagnosis, neuromuscular-skeletal parameters (range of motion and spasticity), gait quality and performance in the functional tests before BTA. RESULTS: Four predictive models were developed (R2 between 0.58 and 0.83; p<0.05) through the use of CART analysis: two at three months and two at six months after BTA application. The results indicated that children with better gait quality, smaller repertoire of functional motor skills, less independence of locomotion and age below four years and six months before BTA presented greater gains in motor skills and independence in mobility. CONCLUSION: The results identified significant clinical parameters that can predict functional outcomes of BTA applications among children with CP. [ABSTRACT FROM AUTHOR]

BACKGROUND: Rearfoot pronation-supination and hip internal-external rotation are commonly assumed to be temporally coupled. Many mechanisms of musculoskeletal injury are proposed based on this assumption. Previous studies suggested that this theoretical coupling does not exist. However, recent experimental studies observed relationships consistent with foot-hip mechanical interdependence. METHODS: Three-dimensional kinematics of the lower extremity of 18 healthy subjects, wearing flat trekking sandals, was measured during the stance phase of normal walking. Rearfoot-shank complex motion in the transverse plane (shank internal-external rotation) and frontal plane (rearfoot eversion-inversion) and hip motion in the transverse plane were analyzed. Cross-correlation coefficients were calculated to investigate temporal similarities between curves of rearfoot-shank and hip motions. Pearson correlations were used to investigate relationships between the timings of the peaks of these motions. FINDINGS: Cross-correlations revealed a strong mean temporal coupling (mean r=0.77, range 0.56 to 0.92) between shank internal-external rotation and hip internal-external rotation and a moderate mean temporal coupling (mean r=0.56, range 0.37 to 0.78) between rearfoot eversion-inversion and hip internal-external rotation. Pearson correlations revealed significant (P

The anatomical connection between latissimus dorsi (LD), thoracolumbar fascia, and contralateral gluteus maximus (GM) enables myofascial force transmission (MFT) between the shoulder, trunk, and hip. This study investigates whether regular sports practice, specifically running, influences this MFT pathway. Given the potential changes in tissue stiffness from sports practice and the importance of this property for MFT, we hypothesize that runners may exhibit greater MFT between the LD and GM, resulting in altered passive properties of the lumbar and hip regions during LD contraction. This study aimed to investigate whether runners present a higher modification in lumbar stiffness and passive properties of the contralateral hip due to LD contraction than sedentary individuals. The lumbar stiffness, hip resting position, passive hip torque, and stiffness of fifty-four individuals were assessed using an indentometer and an isokinetic dynamometer, respectively, in two conditions: LD relaxed, and LD contracted. The main and interaction effects were assessed using a two-way ANOVA. The LD contraction increased lumbar stiffness (p < 0.001; η p 2  = 0.50), externally rotated the hip resting position and increased the passive hip torque and stiffness (p < 0.05; η p 2  > 0.1) in both groups. In addition, runners presented higher lumbar stiffness compared to sedentary in the LD contracted condition (p = 0.017, ES d  = 0.54). Although runners exhibited increased lumbar stiffness during LD contraction, the MFT from the shoulder to the hip joint occurred similarly in both groups., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Interactions between hip and foot biomechanical factors may result in different magnitudes of foot pronation during walking., Objective: To investigate non-linear interactions between hip and foot biomechanical factors and their capability to predict foot pronation during walking and identify the profiles of biomechanical factors that predict greater and lower pronation., Methods: This is a cross-sectional study. Fifty-one women were classified into greater and lower foot pronation during walking. Biomechanical factors measured: (1) foot-ankle varus alignment, (2) hip passive stiffness, (3) isokinetic eccentric strength of hip external rotators, and (4) foot abduction angle. Classification and regression trees (CART) were used to investigate non-linear interactions that predict greater and lower foot pronation., Results: Four main profiles of biomechanical factors were identified as related to greater and lower foot pronation. Profiles for greater pronation were: (1) varus >25.83°; (2) interaction between varus ≤25.83° and hip stiffness ≤0.09 Nm/rad kg -1 ; (3) interaction between varus ≤25.83°, hip stiffness >0.09 Nm/rad kg -1 , and foot abduction >19.58° The profile for lower pronation involved an interaction among varus ≤25.83°, hip stiffness >0.09 Nm/rad kg -1 , and foot abduction ≤19.58° The model had 61 % sensitivity and 96 % specificity, with the total prediction of 78 %. The area under the ROC curve was 0.79 (p = 0.001)., Conclusion: Foot-ankle varus, hip passive stiffness, and foot abduction predicted greater and lower foot pronation. Non-linear interactions between hip and foot factors influence the magnitude of foot pronation during walking. The observed profiles help identify which combinations of biomechanical factors should be assessed in individuals with increased or reduced pronation., Competing Interests: Declarations of competing interest The authors declare no competing interest., (Copyright © 2024. Publicado por Elsevier España, S.L.U.)

This study investigated the kinematic (KmS) and kinetic (KnS) strategies integrating the trunk and lower limbs to achieve maximal kicking performance. Although strategies consisting of individual joint movements or moments are known, strategies combining joint movements or moments of the trunk and lower limbs have been less studied. Fifty adult amateur soccer players were assessed. Peak joint angles and moments of the trunk, the hip of the supporting limb, the hip and knee of the kicking limb, and the velocities of the foot and ball were recorded. Canonical Correlation Analysis evaluated relationships between sets of variables. A combination of greater hip extension and knee flexion of the kicking limb, as a KmS, correlated with better kick performance (Rc = 0.60, p  = 0.004). Furthermore, a combination of larger moments of trunk flexion and rotation, internal rotation of the supporting hip, hip flexion, and knee extension of the kicking limb, as a KnS, were associated with better performance (Rc = 0.74, p  < 0.001). The explained variance was 43% for the KmS and 59% for the KnS. In amateur players, the KmS for better kick performance involved greater hip and knee movement of the kicking limb, while the KnS involved greater moments at the trunk and both lower limbs.

This study aimed to investigate the regularity of the lower limb joint kinematics in runners with and without a history of running-related injuries. The second aim was to verify if the movement pattern regularities are different among the lower limb joints. Eighteen asymptomatic recreational runners with and without a history of running-related injury participated in this study. Lower limb kinematics in the sagittal plane were recorded during running on a treadmill at a self-selected speed. The regularities of the time series of hip, knee, and ankle were analysed using sample entropy (SampEn). A mixed analysis of variance was used to investigate differences between groups and among joints. Runners with a history of injury had lower SampEn values than runners without a history of injury. Ankle kinematics SampEn was higher than that of the knee and hip. Knee kinematics had higher values of SampEn than that of the hip. Runners with a history of running-related injury had greater joint kinematic's regularity. This result suggests that, even in asymptomatic runners, previous injuries could influence the movement pattern regularity. Also, the regularity was different among joints. The ankle demonstrated the lowest regularity, reinforcing the different functions that lower limb joints perform during running.

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., Competing Interests: Declaration of competing interest None, (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study aimed to identify the clinical and biomechanical factors of subjects with excessive foot pronation who are not responsive (i.e., "non-responders") to medially wedged insoles to increase knee adduction external moment. Ankle dorsiflexion range of motion, forefoot-shank alignment, passive hip stiffness, and midfoot passive resistance of 25 adults with excessive bilateral pronation were measured. Also, lower-limb angles and external moments were computed during walking with the participants using control (flat surface) and intervention insoles (arch support and 6° medial heel wedge). A comparison between "responders" (n = 34) and "non-responders" (n = 11) was conducted using discrete and continuous analyses. Compared with the responders, the non-responders had smaller forefoot varus (p = 0.014), larger midfoot passive internal torque peak (p = 0.005), and stiffness measured by the torsimeter (p = 0.022). During walking, non-responders had lower angle peaks for forefoot eversion (p = 0.001), external forefoot rotation (p = 0.037), rearfoot eversion (p = 0.022), knee adduction (p = 0.045), and external hip rotation (p = 0.022) and higher hip internal rotation angle peak (p = 0.026). Participants with small forefoot varus alignment, large midfoot passive internal torque, stiffness, small knee valgus, hip rotated internally, and foot-toed-in during walking did not modify the external knee adduction moment ("non-responders"). Clinicians are advised to interpret these findings with caution when considering the prescription of insoles. Further investigation is warranted to fully comprehend the response to insole interventions among individuals with specific pathologies, such as patellofemoral pain and knee osteoarthritis (OA)., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

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.

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., Competing Interests: Declaration of Competing Interest None of the authors had any conflict of interest during this study., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Fatigue is associated with increased injury risk along with changes in balance control and task performance. Musculoskeletal injury rates in runners are high and often result from an inability to adapt to the demands of exercise and a breakdown in the interaction among different biological systems. This study aimed to investigate whether changes in balance dynamics during a single-leg squat task following a high-intensity run could distinguish groups of recreational runners who did and did not sustain a running-related injury within 6 months. Methods: Thirty-one healthy recreational runners completed 60 s of single-leg squat before and after a high-intensity run. Six months after the assessment, this cohort was separated into two groups of 13 matched individuals with one group reporting injury within this period and the other not. Task performance was assessed by the number of repetitions, cycle time, amplitude, and speed. To evaluate balance dynamics, the regularity and temporal correlation structure of the center of mass (CoM) displacements in the transverse plane was analyzed. The interaction between groups (injury, non-injured) and time (pre, post) was assessed through a two-way ANOVA. Additionally, a one-way ANOVA investigated the percent change difference of each group across time. Results: The injured group presented more regular (reduced entropy; 15.6%) and diffusive (increased short-term persistence correlation; 5.6%) CoM displacements after a high-intensity run. No changes were observed in the non-injured group. The within-subject percent change was more sensitive in demonstrating the effects of fatigue and distinguishing the groups, compared to group absolute values. No differences were observed in task performance. Discussion: Runners who were injured in the future demonstrate changes in balance dynamics compared to runners who remain injury-free after fatigue. The single-leg squat test adopted appears to be a potential screening protocol that provides valuable information about balance dynamics for identifying a diminished ability to respond to training and exercise., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Aquino, Liddy, Napoli, Fonseca, van Emmerik and Busa.)

Objective  To compare the spatial-temporal parameters and walking kinematics of toddlers wearing biomimetic shoes, regular shoes (daily use owned shoes), and barefoot. Methods  Spatial-temporal parameters (speed, step length, and stride width), the mean vertical displacement of the center of mass (COM), knee flexion peak, and maximal foot height were analyzed. Results  Children were not different in biomimetic shoes and barefoot conditions on speed, step length, and COM vertical displacement. There was no difference among conditions on stride width and foot height. The knee flexion peak was greater in shod conditions than barefoot. The regular shoes showed greater COM vertical displacement than biomimetic shoes and barefoot. Conclusion  The findings showed that shoes affected the walking pattern in young children, but a shoe with a biomimetic design had a lesser effect on the walking pattern., Competing Interests: Conflito de Interesses Liria Akie Okai-Nóbrega and Ana Paula Lage work at Anamê Science and Technology in Child Health Products. The others authors do not have conflicts of interest. Dr. Lage reports grants from Inovation award SESI/SENAI, during the conduct of the study; In addition, Dr. Lage has a patent Dynamic Insole (Brazil) pending, and a patent Biomimetic Shoe (Brazil, USA, India, Japan, UE) pending., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution 4.0 International License, permitting copying and reproduction so long as the original work is given appropriate credit ( https://creativecommons.org/licenses/by/4.0/ ).)

Older runners (OR) are increasing their participation in races. Aging may impact the adopted running pattern. Hence, the analysis of stiffness and the inter-joint lower limb coordination in the sagittal plane could contribute to investigating this impact. This study aimed to compare the vertical stiffness (K vert ) and the inter-joint lower limb coordination in the sagittal plane between younger runners (YR) and OR. This cross-sectional study recruited 15 YR males and 15 OR males. The pelvis and lower limb motions were assessed while running on a treadmill at self-selected (range OR: 1.94-3.75 m.s -1 , YR: 2.08-4.17 m.s -1 ) and fixed speeds (3.33 m.s -1 ). Hip-ankle, knee-ankle, and hip-knee coupling angle (CA) and its variability (CAV) were extracted using the vector coding method. Mann-Whitney U tests compared K vert between groups at each running speed. Watson's U 2 tests compared the mean CA between groups in three intervals of the contact phase at each running speed. Statistical Parametric Mapping independent t-test compared the CAV curve between groups at each running speed. OR showed greater K vert than YR at both speeds. Hip-ankle CA pattern differed between groups during the early stance at both speed conditions. OR showed in-phase, distal dominancy in hip-ankle CA, whereas YR showed anti-phase, proximal dominancy. Knee-ankle CA was distinct only at self-selected speed, in which OR showed in-phase, proximal dominancy, while YR exhibited anti-phase, proximal dominancy. CAV did not differ between groups. The findings showed that OR adopted a stiffer pattern characterized by distinct inter-joint lower limb CA, at early stance, during self-selected and fixed speeds., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The upper body and trunk muscles are crucial to perform soccer kicks. Resistance training targeting these muscles may modify the pattern adopted during kicking. This study aimed to investigate the effect of resistance training of the arm and anterior trunk muscles on instep kicking kinematics. Twenty-six male participants were randomly allocated into a training group or control group. The training group underwent resistance training of arm and trunk muscles and practiced the instep kick for 8 weeks. The control group only practiced kicking during the same period. The trunk, hip, and knee kinematics were assessed during the instep kick before and after the intervention. Kinematics were analyzed according to their data distribution with statistical parametric or nonparametric mapping. The effect of the training on the 1-repetition maximum test was analyzed using a repeated-measures multivariate analysis of variance. The training group showed greater hip extension after the training during the backswing phase (Hedge g effect size of 0.316-0.321) and increased 1-repetition maximum for all exercises. There were no other differences. The present study documented the nonlocal effect of strengthening training in which arm and trunk muscle training resulted in changes in hip kinematics during the backswing phase of the instep kick.

Neuromuscular fatigue (NMF) reduces the musculoskeletal system's ability to produce force during activities like running. Analysis of motor behaviour's regularity may identify motor system deficits caused by fatigue. The present study investigated whether the NMF of lower limb extensors alters the regularity of running movement and whether this possible effect remains over time. Crossover study with two randomised conditions: NMF and control. Twelve healthy young males participated in this study. Hip, knee, and ankle angles (sagittal plane) and centre of mass (CoM) linear accelerations were assessed during treadmill running at self-selected speed in four assessment conditions: Baseline (pre-NMF), and after NMF (NMF condition) or after rest (control), at the 1 st (Time&#95;1), 10 th (Time&#95;10) and 20 th (Time&#95;20) minutes. Kinematics regularity was measured as Sample Entropy. Repeated measures ANOVAs were used (α = 0.05). NMF reduced regularity of lower limb joints during running, and these effects remained up to 20 minutes. No changes were observed in the CoM accelerations' regularity. The regularity reductions may be an adaptive solution for the motor system to maintain the task performance. The measure of regularity of the lower limb joints' motion is sensitive to NMF and can identify states with deficits in muscles' force production capacity in running.

Objective: To identify subgroups of runners' profiles who had or did not have a History of Running-Related Injury in the Shank and Foot (HRRI-SF)., Design: Cross-sectional., Methods: Clinical measures of passive ankle stiffness (measured as ankle position (compliance) to index passive joint stiffness), forefoot-shank alignment, peak torque of ankle plantar flexors, years of running experience, and age were analyzed through Classification and Regression Tree (CART)., Results: The CART identified four subgroups of runners with a greater prevalence of HRRI-SF: (1) ankle stiffness ≤0.42°; (2) ankle stiffness >0.42°, age ≤23.5 years, and forefoot varus >19,64°; (3) ankle stiffness >0.42°, age >62.5 years, and forefoot varus ≤19.70°; (4) ankle stiffness >42°, age >62.5 years, forefoot varus >19.70°, and running experience ≤7 years. Three subgroups had a lower prevalence of HRRI-SF: (1) ankle stiffness >0.42° and age between 23.5 and 62.5 years; (2) ankle stiffness >0.42°, age ≤23.5 years, and forefoot varus ≤14.64°; (3) ankle stiffness >0.42°, age >62.5 years, forefoot varus >19.7°, and running experience >7 years., Conclusion: One runner profile subgroup showed that higher ankle stiffness could predict HRRI-SF without association with other variables. Distinct interactions among variables characterized the other subgroups' profiles. The identified interactions among the predictors used to characterize the runners' profiles could be used in clinical decision-making., Competing Interests: Declaration of competing interest None declared., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Biofeedback has been used by rehabilitation professionals in the treatment of poststroke function impairments., Purpose: Investigate the efficacy of any type of biofeedback intervention for the treatment of upper limb function in individuals following stroke., Study Design: Systematic review of literature with meta-analysis., Methods: Literature searches were conducted using MESH terms and text words in PubMed, Lilacs, Scielo, Scopus, PEDro, and Web of Science databases. The main outcome was improvement in upper limb's motor function and motor function in activities of daily living. We calculated the Mean Difference and Standardized Mean Difference for the assessment scales reported as primary outcome. The methodological quality of included studies was assessed using PEDro scale. The overall quality of the evidence was assessed using GRADE system., Results: From 1360 articles identified, 16 were included in the review (09 in the meta-analysis). Three forest plots of hemiparesis and one of hemiplegia showed that biofeedback therapy associated with conventional therapy has a greater improvement in participants upper limb motor function when compared to isolated conventional therapy. Two forest plots of hemiparesis and one of hemiplegia showed no superiority in participants improvement for biofeedback associated with conventional therapy when compared to isolated conventional therapy., Conclusion: Biofeedback therapy associated with conventional therapy showed a small clinical effect when associated to conventional therapy and very low quality of evidence. Although further research with higher quality evidence is needed., (Copyright © 2022. Published by Elsevier Inc.)

Background: Postural control results from non-linear interactions of multiple neuromusculoskeletal elements and contextual factors. The use of non-linear analyses that consider the temporal evolution of postural adjustments, such as sample entropy, could inform about the changes in postural control due to contextual disturbances such as sleep deprivation., Research Question: What are the effects of sleep deprivation on static postural control and dynamic stability in healthy young adults?, Methods: A quasi-experimental study was performed with 17 healthy young males submitted to 24 h of monitored sleep deprivation. The postural control was measured using sample entropy, area, and total average velocity of the center of pressure on a force platform. The dynamic stability was measured using the Modified Star Excursion Balance Test (SEBTm) composite score for each lower limb. Repeated-measures analysis of variance (baseline × 12 h × 15 h × 18 h × 21 h × 24 h of sleep deprivation) verified the effect of sleep deprivation in the postural control variables. Paired t-test compared the composite score of the SEBTm between baseline and 24 h sleep deprivation., Results: Sample entropy decreased after 18 h of sleep deprivation (p = 0.032) and 24 h of sleep deprivation (p = 0.001). Despite the significant main effect for the area (p = 0.012) and speed (p = 0.007) of the center of pressure, no pairwise differences were identified in the post hoc analysis. The non-dominant lower limb SEBTm composite score was reduced after 24 h of sleep deprivation (p = 0.033), and no difference was observed in the dominant limb., Significance: Sleep deprivation reduced the adaptability in static postural control and dynamic stability of the non-dominant lower limb of healthy young male adults. Sample entropy seemed more sensitive to capture the effects of sleep deprivation than the classical postural control variables., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Walking experience is crucial for inter-joint coordination during gait acquisition. Toddlers show asymmetrical lower limb function during early locomotion for transferring body weight (regulatory limb) and steering the direction of walking (impulse limb). This study aimed to investigate the association between coordination patterns and walking experience, and between coordination variability and walking experience according to healthy toddlers' lower limb function and stance periods. Typically developing toddlers (n = 22; 17.27 ± 3.13 months) were distributed into two groups: up to (LWE) and greater than (GWE) three months of walking experience. The lower limbs were classified as regulatory or impulse limb and analyzed during the onset (SO), mid (MS), and late (LS) stance intervals. Hip-ankle, knee-ankle, and hip-knee coupling angle (CA) and its variability (CAV) were assessed. A relationship was found between inter-joint coordination pattern and groups, which was distinct according to stance period and lower limb function: (a) hip-ankle CA: at SO for both limbs, MS for the regulatory limb, and LS for the impulse limb; (b) knee-ankle CA: at SO for both limbs and MS for the regulatory limb; (c) hip-knee CA: at SO for both limbs, at MS for the regulatory limb, and LS for the impulse limb. These findings were linked to differences observed in distal joints between groups, mainly at the ankle during stance onset. The CAV was negatively associated with walking experience only in the regulatory limb in the following variables: hip-ankle at MS, knee-ankle at SO, and hip-knee at LS. Findings showed different functional roles of the lower limbs in dealing with the demands of balance and propulsion during early walking., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Alterations of frontal plane patellar alignment could be related to lower limb disorders. Clinical assessment must be able to identify the influence of non-local factors in patellar alignment., Objective: To identify the influence of lower limb torque, range of motion (ROM), and foot alignment on patellar rotation in healthy athletes., Methods: This cross-sectional study was performed with 232 healthy basketball and volleyball elite athletes. Participants were assessed in preseason for: patellar medial and lateral rotation (Arno angle), passive hip internal rotation (IR) ROM, iliotibial band flexibility, hip abductors and external rotators (ER) torque, shank-forefoot alignment (SFA), and ankle dorsiflexion ROM. Hierarchical multiple linear regression was performed to identify if these variables and sex, age, and body mass could be associated with patellar rotation in a standing position., Results: Hip ER isometric torque explained a small part (10%) of the variance of the Arno angle in healthy athletes (R² change=0.10; unstandardized ß=11.74 (95% CI 6.82, 16.65); Standardized Coefficient Beta=0.32) and sex explained 2% of its variance (R² change=0.02; unstandardized ß= 2.42 (95% CI 0.32, 4.52); Standardized Coefficient Beta=0.15). After controlling for sex, hip ER torque explained 9% of Arno angle variance (R² change=0.09; unstandardized ß= 11.09 (95% CI 6.43, 15.76; Standardized Coefficient Beta=0.31). The other variables were not associated with patellar rotation., Conclusions: Hip ER torque may influence patellar rotation in different directions (medial or lateral rotation). Possible mechanisms that explain the contribution of higher and lower hip ER torque in lateral and medial patellar rotation, respectively, are discussed., (Copyright © 2022 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier España, S.L.U. All rights reserved.)

Introduction: This study aimed to evaluate the effect of scapular dyskinesis and its interaction with hand dominance and humerothoracic angles on three-dimensional scapular kinematics in asymptomatic individuals in all planes of arm motion., Methods: Forty-five asymptomatic participants, seventeen men and twenty-eight women, were separated into two groups: with (n = 22) and without scapular dyskinesis (n = 23) according to the Yes/No classification. Scapular kinematic data of dominant and non-dominant sides in both groups were measured with an electromagnetic tracking device during arm elevation and lowering phases in scapular, frontal and sagittal planes. A linear mixed model of covariance adjusted for age and BMI was used, which included hand dominance (dominant and non-dominant), group (with and without scapular dyskinesis), angles (30°, 60°, 90°, and 120°), and the interaction effect (group × hand dominance × humerothoracic angle)., Results: There was a significant interaction effect on scapular anterior tilt and upward rotation in the sagittal plane, and for internal rotation and anterior tilt in the frontal and scapular planes. The effects of hand dominance on three-dimensional scapular kinematics, as increased anterior tilt, internal rotation and upward rotation, were greater in individuals without scapular dyskinesis., Conclusion: The effects of dominant side as increased upward rotation, internal rotation, and anterior tilt at higher humerothoracic angles for all planes of arm motion, were greater in individuals without scapular dyskinesis. Our findings may assist the scapular assessment which in individuals without scapular dyskinesis, bilaterally, possible between side differences in the scapular motions may be related to a dominance effect., Competing Interests: Declaration of competing interest All data are presented honestly, without fabrication, or data manipulation. The authors have no conflicts of interest., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Proper ankle dorsiflexion range of motion (ADF-ROM) allows the anterior roll of the tibia relative to the foot during the midstance phase of gait, which contributes to forward movement of the body. Individuals with reduced passive ADF-ROM may present altered movement patterns during gait due to an inefficient anterior tibial roll over the support foot during the stance phase., Research Question: What is the influence of reduced passive ADF-ROM on the pelvic and lower limb movements and spatiotemporal parameters during gait?, Method: Thirty-two participants divided into two groups according to the degree of passive ADF-ROM-less than 10° (lower ADF-ROM group) or greater than 15° (higher ADF-ROM group) -were subjected to gait assessment using a three-dimensional motion analysis system. Independent t-tests were used to compare the pelvic and lower limb movements and spatiotemporal gait parameters between the groups on this cross-sectional study., Results: The lower ADF-ROM group had shorter step length, lower peak of pelvic ipsilateral rotation angle, and lower hip and knee maximum flexion angles in the stance phase (p < 0.05). In addition, the peaks of the ankle and forefoot-rearfoot dorsiflexion angles were smaller in the reduced ADF-ROM group (p < 0.05). The between-group differences presented effect sizes varying from moderate to large., Significance: Individuals with reduced passive ADF-ROM presented reduced foot and ankle dorsiflexion, knee and hip flexion, and pelvis rotation movements and shorter step length during gait. However, no differences in foot pronation were noted between groups. Therefore, individuals with reduced passive ADF-ROM present alterations in the lower limb and pelvic movements during gait., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Objective  To evaluate the biomechanical behavior of the medial longitudinal arch (MLA) of the foot and the kinematic parameters of the lower limbs with biomimetic footwear (BF) and non-biomimetic (NB1, NB2, NB3 and NB4) footwear in children at the beginning of the gait acquisition phase. Methods  Four toddlers were evaluated at the beginning of the gait acquisition phase under the following conditions: walking barefoot, ambulation with BF and NB1, NB2, NB3 and NB4 footwear in hard floor. BF is described as biomimetic because of its property of emulating natural and irregular floors through a dynamic internal insole. The MLA and kinematics of the hip, knee, and ankle during gait were evaluated by three-dimensional motion analysis system. The similarity between the kinematic curves of barefoot and footwear conditions was analyzed by root mean square error (RMSE). Results  The use of BF presented the highest magnitude of MLA and the greatest difference in relation to barefoot condition (higher RMSE). The BF showed less difference in the kinematics of the knee and ankle joints during gait when compared to barefoot condition (lower RMSE). NB2 footwear presented hip kinematics more similar to barefoot condition (lower RMSE). Conclusion Biomimetics footwear and NB2 shoes (both with wider forefoot region) generated smaller differences in lower limbs compared to barefoot. In addition, the MLA was higher in the BF, probably because different design from other shoes., Competing Interests: Conflito de interesses A Dra Liria Akie Okai-Nóbrega e a Dra Ana Paula Lage trabalham com pesquisa na Anamê Ciência e Tecnologia em Saúde Infantil Ltda., (Sociedade Brasileira de Ortopedia e Traumatologia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commecial purposes, or adapted, remixed, transformed or built upon. ( https://creativecommons.org/licenses/by-nc-nd/4.0/ ).)

Competing Interests: Competing interests: None declared.

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., (Copyright © 2021 Elsevier B.V. All rights reserved.)

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., (Copyright © 2021 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

The multibody nature of the musculoskeletal system makes each applied force potentially accelerate all body segments. Hence, muscles' actions on the kinematics of crossed and non-crossed joints should be estimated based on multibody dynamics. The objective of this study was to systematically investigate the actions of main lower limb muscles on the sagittal-plane angular kinematics of the hip, knee, and ankle joints, during upright standing and gait. Subject-specific simulations were performed to compute the muscle-tendon forces based on three-dimensional kinematic data collected from 10 able-bodied subjects during walking at preferred speed and during relaxed standing posture. A subject-scaled model consisting of the lower limb segments, 19 degrees of freedom and 92 Hill-type muscle-tendon units was used. Muscle-induced joint angular accelerations were estimated by Induced Acceleration Analysis in OpenSim. A comprehensive description of the estimated joint accelerations induced by lower limb muscles was presented, for upright standing and for the whole gait cycle. The observed muscle actions on crossed and non-crossed joints were phase- and task-specific. The main flexors and extensors for each joint were reported. Particular biarticular muscles presented actions opposite to their anatomical classification for specific joints. Antagonist muscle actions were revealed, such as the hitherto unknown opposite actions of the soleus and gastrocnemius at the ankle, and of the iliopsoas and soleus at the knee and ankle, during upright standing. Agonist actions among remote muscles were also identified. The presented muscle actions and their roles in joint kinematics of bipedal standing and walking contribute to understanding task-specific coordination., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Fast walking may require a non-uniform change of dynamic stiffness among lower limb joints to deal with this daily task's demands. The change of dynamic joint stiffness may be distinct between females and males. This study aimed to test for differences in dynamic stiffness among lower limb joints in response to increased walking speed in males and females. Thirty-five participants walked in two randomized conditions: self-selected speed and fast speed (25% greater than the self-selected speed). Dynamic stiffnesses of the ankle, knee, and hip were calculated as the linear slope of the moment-angle curve's regression line during their major power absorption phase of the walking cycle. The comparison between conditions showed that the knee (p < 0.001) and hip (p = 0.031) increased their stiffness at the fast compared to self-selected speed. Ankle stiffness was not different between conditions (p = 0.818). The comparison among joints across speeds showed that the knee had a greater increase than the ankle (p = 0.001) and hip (p < 0.001), with no difference between ankle and hip (p = 0.081). The sex of the participant influenced only the ankle stiffness, in which males had greater stiffness than females (p = 0.008). These findings demonstrated that the lower limb joints changed their dynamic stiffness differently, and only the ankle stiffness was influenced by sex. The non-uniform adjustments of stiffness may provide the necessary stability and allow the individual to deal with greater demand for walking fast., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

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., (Copyright © 2022. Published by Elsevier Inc.)

Background: Increased foot pronation during walking has been associated with low back pain. This association may be due to the impact of increased pronation on pelvic motion., Objective: To investigate the effects of increased bilateral foot pronation on pelvic kinematic in frontal and transverse planes during the loading response phase of gait., Methods: Pelvic, hip, and foot angular positions of 20 participants were collected while they walked at fast speed wearing flat and medially inclined insoles inserted in the shoes. Pelvic motion in frontal and transverse planes was analyzed during the loading response phase. Foot eversion-inversion was analyzed during the complete stance phase to verify the insoles effectiveness in inducing increased pronation and to exclude excessive pronators., Results: Inclined insoles were effective in inducing increased foot pronation. Pelvic and hip motion were altered in the increased pronation condition compared to the control condition. In the frontal plane, mean pelvic position was more inclined to the contralateral side (mean difference [MD]: 0.54°; 95%CI: 0.23, 0.86) and its range of motion (ROM) was reduced (MD: 0.50°; 95%CI: 0.20, 0.79). In the transverse plane, mean pelvic position was less rotated toward the contralateral leg (MD: 1.03°; 95%CI: 0.65, 1.60) without changes in ROM (MD: 0.04°; 95%CI: -0.17, 0.25). The hip was more internally rotated (MD: 1.37°; 95%CI: 0.76, 1.98) without changes in ROM (MD: 0.10°; 95%CI: -1.02, 1.23)., Conclusion: Increased bilateral foot pronation changes pelvic motion during walking and should be assessed, as a contributing factor to possible pelvic and lower back disorders., (Copyright © 2021 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier España, S.L.U. All rights reserved.)

Objective: The aim of this systematic review was to investigate the effect of exercise-based programmes in the prevention of non-contact musculoskeletal injuries among football players in comparison to a control group., Design: Systematic review and meta-analysis of randomised controlled trials., Data Sources: MEDLINE, EMBASE, CENTRAL, CINAHL, PEDro and SPORTDiscus databases were searched from the earliest record to January 2021., Eligibility Criteria: Studies were eligible if they (1) included football players aged 13 years or older, (2) used exercise-based programmes as intervention, (3) presented the number of non-contact musculoskeletal injuries (ie, defined as any acute sudden onset musculoskeletal injury that occurred without physical contact) and exposure hours for each group, and (4) had a control group (eg, usual training, minimal intervention, education). All types of exercise-based prevention programmes were eligible for inclusion. Risk of bias for each included study and overall quality of evidence for the meta-analysis were assessed., Results: Ten original randomised controlled trials with 13 355 football players and 1 062 711 hours of exposure were selected. Pooled injury risk ratio showed very low-quality evidence that exercise-based prevention programmes reduced the risk of non-contact musculoskeletal injuries by 23% (0.77 (95% CI 0.61 to 0.97)) compared with a control group., Conclusion: Exercise-based prevention programmes may reduce the risk of non-contact musculoskeletal injuries by 23% among football players. Future high-quality trials are still needed to clarify the role of exercise-based programmes in preventing non-contact musculoskeletal injuries among football players., Prospero Registration Number: CRD42020173017., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

This study aimed to investigate the effects of knee flexion during the preparation phase of a serve on the tennis serve performance, using inertial sensors. Thirty-two junior tennis players were divided into two groups based on their maximum knee flexion during the preparation phase of serve: Smaller (SKF) and Greater (GKF) Knee Flexion. Their racket velocity, racket height, and knee extension velocity were compared during the tennis serve. Inertial sensors tracked participants' shank, thigh, and racket motions while performing five first, flat, and valid serves. Knee flexion was analysed during the preparation phase of serve, knee extension velocity after this phase, racket velocity just before ball impact, and racket height at impact. Pre-impact racket velocity (mean difference [MD] = 3.33 km/h, p = 0.004) and the knee extension velocity (MD = 130.30 °/s, p = 0.012) were higher in the GKF than SKF; however, racket impact height was not different between groups ( p = 0.236). This study's findings support the importance of larger knee flexion during the preparation phase of serve-to-serve performance. This motion should be seen as a contributor to racket velocity.

The addition of a load during walking requires changes in the movement pattern. The investigation of the dynamic joint stiffness behavior may help to understand the lower limb joints' contribution to these changes. This study aimed to investigate the dynamic stiffness of lower limb joints in response to the increased load carried while walking. Thirteen participants walked in two conditions: unloaded (an empty backpack) and loaded (the same backpack plus added mass corresponding to 30% of body mass). Dynamic stiffness was calculated as the linear slope of the regression line on the moment-angle curve during the power absorption phases of the ankle, knee, and hip in the sagittal plane. The results showed that ankle (P = .002) and knee (P < .001) increased their dynamic stiffness during loaded walking compared with unloaded, but no difference was observed at the hip (P = .332). The dynamic stiffness changes were different among joints (P < .001): ankle and knee changes were not different (P < .992), but they had a greater change than hip (P < .001). The nonuniform increases in lower limb joint dynamic stiffness suggest that the ankle and knee are critical joints to deal with the extra loading.

The purpose of this study was to investigate the angular kinetic energy transfers and expenditure among the trunk (bisegmented), the pelvis and the kick limb during maximal soccer instep kicking, and to characterize kicking kinetics and kinematics. Eighteen adult male amateur soccer players (24.0 ± 4.1 years old) were assessed. Three-dimensional kinematics and ground reaction force were measured. A 6-degrees-of-freedom model was assumed, comprising the upper trunk, lower trunk, pelvis, thigh, shank and foot, and the thoraco-lumbar, lumbo-pelvic, hip, knee, and ankle joints. Angular kinematics and joint moments were computed. Power flow analysis was done by calculating the joint powers (to describe joint-to-segments energy transfers) and the proximal and distal segment powers (to describe segment-to-segment transfers). Power, kinematic and kinetic time series were presented to describe the energy flows' directions. The total mechanical energy expenditure (TMEE) at each joint was also calculated. The TMEEs pointed to substantial energy expenditure at the trunk (27% of the summed work produced by the analyzed joints). In the initial phases of kicking, the trunk generates downward energy flows from the upper to the lower trunk and from the lower trunk to the pelvis, and then to the lower limb, sequentially, which favors angular motions for ball contact. There is a formation and release of a tension arc only at the hip joint, and deceleration of the segments slightly sooner than ball contact, differently from theoretical accounts. There are energy flows, hitherto unknown, among the trunk, pelvis and kick limb, revealing mechanical strategies of kicking., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Adherence to the use of recommended measures/criteria for return to sport clearance after anterior cruciate ligament reconstruction is crucial for successful rehabilitation., Objectives: The purpose of this study was to describe the current clinical practice of Brazilian physical therapists that treat patients after anterior cruciate ligament reconstruction, including the measures/criteria used to support the decision-making process regarding return to sport. The secondary aim was to investigate factors associated with the use of the most recommended measures/criteria for return to sport., Methods: An electronic survey questionnaire was sent to Brazilian physical therapists. The survey consisted of questions about demographics and professional and clinical practice data related to anterior cruciate ligament reconstruction postoperative rehabilitation and return to sport criteria. Descriptive statistics and chi-square tests were used for analyses., Results: A sample of 439 professionals participated in the survey. Only 6.4% of the physical therapists use the most recommended measures/criteria for return to sport after anterior cruciate ligament reconstruction. Professional certification in Sports Physical Therapy was the only factor associated with the use of these recommended measures/criteria (p=0.02). The measures most used for return to sport clearance were related to physical factors (65.3% to 75.1%), such as range of motion and muscle strength. A small number of professionals use questionnaires to assess functional (16.6%) and psychological (19.1%) aspects of their patients to support the decision-making process., Conclusion: In their clinical practice, most Brazilian physical therapists do not use the recommended measures/criteria for return to sport after anterior cruciate ligament reconstruction., (Copyright © 2020 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier España, S.L.U. All rights reserved.)

Movement analysis provides a vast amount of data, which, frequently, are not used in the clinical decision-making process. For example, traditional gait data visualization is based on a time-based display of joint angles, but part of the information is lost when these time-series are averaged across different gait strides. Horizon graph is a data display method that increases the density of time-series data by horizontally dividing and layering multiple filled line graphs. This higher data density increases the amount of information displayed in the same graph and, consequently, enables visual data comparisons between multiple time series. Horizon graph of kinematic data allows displaying several cycles of different joints and their respective continuous symmetry ratio between sides. The aim of this work is to introduce the Horizon graph as a method to analyze kinematic gait data and help to characterize its symmetry. Examples of Horizon graph application to running is offered. Horizon graph may prove to be a useful clinical tool to visualize kinematic time-series and facilitate their clinical interpretation.•Continuous gait time series is a powerful tool for clinical analysis.•Horizon graph, higher data density graph, increases the information displayed.•Horizon graph is a clinical tool to visualize kinematic curves., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:, (© 2021 The Authors. Published by Elsevier B.V.)

The midfoot joint complex (MFJC) is related to the mechanics and efficiency of the walking propulsive phase and low midfoot passive stiffness may require compensatory foot and ankle joint moments to avoid excessive pronation and inefficient propulsion. This study aimed to investigate the kinematics and kinetics of the MFJC and ankle during the propulsive phase of walking in subjects with larger and smaller midfoot passive stiffness. MFJC passive stiffness of 20 healthy adult participants, and the kinematics and kinetics of the MFJC (forefoot-rearfoot) and ankle (rearfoot-shank) during the stance phase of walking were measured. The participants were divided equally into two groups according to the MFJC passive stiffness. Ranges of motion (ROM) and mean joint moments were computed for the late stance. Independent t-tests (α = 0.05) revealed that subjects with lower midfoot passive stiffness showed an increased MFJC sagittal ROM (flattened longitudinal arch) (p = 0.002), increased ankle frontal ROM (more everted positions) (p = 0.002), increased MFJC frontal ROM (more inverted positions) (p = 0.019), as well as a tendency for larger ankle sagittal ROM (p = 0.056). They also showed increased MFJC (p = 0.021) and ankle (p = 0.018) moments in the sagittal plane, increased MFJC moment in the frontal plane (p = 0.047) and a tendency for a predominant ankle moment in the frontal (p = 0.058). Foot and ankle joint moments are possible strategies to reduce pronation and improve propulsion, but not sufficient to prevent the altered kinematics related to low midfoot stiffness. Therefore, midfoot passive stiffness is critical for foot and ankle kinematics and kinetics during walking propulsive phase and is a potential target of interventions., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: To investigate whether a common measure of sagittal pelvic torsion based on the superior iliac spines behave similarly to predictions of a rigid (non-torsioned) plane, when leg length discrepancies (LLD) are induced., Method: Twenty-four young asymptomatic participants were subjected to pelvic posture measurements that use the anterior-superior iliac spines (ASISs) and posterior-superior iliac spines (PSISs) as references, while standing on level ground and with a one-, two- and three-centimeter lifts under the left foot. A special caliper with digital inclinometers was used. The following angles were measured: angles of the right and left PSIS-to-ASIS lines; right-left relative angle (RLRA), as the angle between the right and left PSIS-to-ASIS lines, which is a traditional lateral-view measure intended to detect sagittal torsions; angle of the inter-ASISs line; angle of the inter-PSISs line; anterior-posterior relative angle (APRA), as the angle between the inter-ASISs and inter-PSISs lines. According to trigonometric predictions based on the geometry given by the lines linking the superior iliac spines (i.e. a trapezoid plane), a pure lateral tilt of the pelvis, without interinnominate sagittal motion, would change RLRA in a specific direction and would not change APRA., Results: Repeated-measures ANOVAs revealed that RLRA (p<0.001) and right and left PSIS-to-ASIS angles (p≤0.001) changed, and APRA did not change (p=0.33), as predicted., Conclusions: At least part of the sagittal torsion detected by measures that assume the PSIS-to-ASIS angles as the sagittal angles of the innominates is due to pelvic geometry and not to the occurrence of actual torsion, when LLDs are induced., (Copyright © 2021. Published by Elsevier Inc.)

Objective: The objective was to establish normative data for hip strength, flexibility, and stiffness in male soccer athletes and to investigate the effect of age and limb dominance on these variables., Design: Cross-sectional., Setting: Soccer team physical therapy department., Participants: A total of 293 asymptomatic male soccer athletes were assessed. Elite youth players aged 15-17 years and professional adult players aged 18-29 years old., Main Outcome Measures: Rectus femoris, iliopsoas, hamstring muscle flexibility, passive hip stiffness, and isometric hip strength were measured using a goniometer, inclinometer, and handheld dynamometer, respectively. Descriptive and mixed analyses of variance were used as statistical procedures., Results: The dominant limb had lower iliopsoas (P = 0.010) and rectus femoris (P = 0.003) flexibility and higher external rotators torque compared to the non-dominant limb (P = 0.006) in both age groups. In adult athletes, the dominant limb had lower hip stiffness than the non-dominant limb (P = 0.002). Adults had higher hip external rotator torque than younger athletes (P < 0.0001). No differences were observed for hamstrings flexibility and hip extensors torque., Conclusion: This study provided normative data of hip strength, flexibility, and stiffness for youth and adult male soccer athletes. In addition, there were no clinically relevant inter-limb differences., Competing Interests: Declaration of competing interest None., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

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.

Objective: To compare the gait event identification of five algorithms recommended in the literature with those provided by force plate (gold standard) in children with unilateral or bilateral spastic cerebral palsy (SCP)., Methods: This was a cross-sectional study of the gait of three girls and four boys with a mean age of 8.6±4.7 years. Four children had unilateral SCP with an equinus gait pattern, and the remaining three children exhibited bilateral SCP with a slide/drag gait pattern. Kinematic and kinetic gait data were collected during barefoot walking at a comfortable speed. From a total of 202 steps, the detection of 202 foot-strike (FS) and 194 toe-off (TO) events by each algorithm was compared with the detection of these same events by the force plate. The error between the events detected by the algorithms and those detected by the force plate was determined in milliseconds. Repeated measures ANOVA was used to compare the errors among the algorithms., Results: The algorithm reported by Ghoussayni et al. showed the best performance in all situations, except for the identification of FS events on the unaffected side in children with unilateral SCP. For these events, the algorithms reported by Desailly et al. and Zeni et al. showed the best performance., Conclusion: Ghoussayni et al.'s algorithm can be used to detect gait events in children with SCP when a force plate is not available., (Copyright © 2019 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.)

Collective behaviors in sports teams emerge from the coordination between players formed from their perception of shared affordances. Recent studies based on the theoretical framework of ecological dynamics reported new analytical tools to capture collective behavior variables that describe team synergies. Here, we introduce a novel hypothesis based on the principles of tensegrity to describe collective behavior. Tensegrity principles operate in the human body at different size scales, from molecular to organism levels, in structures connected physically (biotensegrity). Thus, we propose that a group of individuals connected by information can exhibit synergies based on the same principles (group-tensegrity), and we provide an empirical example based on the dynamics of a volleyball team sub-phase of defense.