The effects of core muscle fatigue on lower limbs and trunk during single-leg drop landing: A comparison between recreational runners with and without dynamic knee valgus.

BACKGROUND: A deficit in neuromuscular trunk control can impact the lower limb motion, predisposing runners to injuries. This deficit may show a greater impact on runners with dynamic knee valgus. This study aimed to compare the effect of core fatigue on kinetic, kinematic, and electromyographic parameters of the trunk and lower limbs during single-leg drop landing between runners with and without dynamic knee valgus. METHODS: Twenty-seven recreational runners were allocated to the valgus (n = 14) and non-valgus groups (n = 13). They performed the test before and after a fatigue protocol, taking a step forward and landing on the force platform while maintaining balance. The fatigue protocol included isometric and dynamic exercises performed consecutively until voluntary exhaustion. The vertical ground reaction force, the sagittal and frontal plane angles, and the electromyographic activity were evaluated. The integral of electromyographic activity was calculated into three movement phases. ANOVA with repeated measures was used to verify the group, time, and interaction effects. RESULTS: After fatigue, both groups showed a significant reduction in the minimum (p = 0.01) and maximum (p = 0.02) knee angles in the frontal plane (more dynamic knee valgus) and greater gluteus medius activity (p = 0.05) from the peak of knee flexion to the end of the movement. The valgus group had a greater hip excursion (p = 0.01) and vertical linear shoulder displacement (p = 0.02) than the non-valgus. CONCLUSION: Our results suggest that core fatigue can impact the local muscle and the distal joint and that the groups presented different strategies to deal with the demand during landing.

Effects of Biomimetic Shoes on Healthy Young Children's Gait.

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.

Effects of Biomimetic Shoes on Healthy Young Children's Gait / Efeitos do uso de calçado biomimético na marcha de crianças típicas

Abstract 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.

Resumo Objetivo O objetivo deste trabalho foi comparar os parâmetros espaço temporais e cinemáticos da marcha de crianças típicas em três condições: descalças, usando calçados biomiméticos e, calçados de uso diário (não biomiméticos - próprios das crianças). Métodos Foram analisadas variáveis espaço temporais (velocidade, comprimento e largura da passada), deslocamento vertical do centro de massa (CM), pico de flexão do joelho e altura máxima do pé, coletados via avaliação tridimensional do movimento. Resultados Comparado com a condição descalça, o uso do calçado biomimético não foi estatisticamente diferente em relação a velocidade da marcha, comprimento da passada e altura do pé. A largura da passada e a altura do pé não foi diferente estatisticamente entre as condições estudadas. O pico de flexão do joelho foi maior nas condições com calçados comparado a condição descalça. Os calçados de uso diário apresentaram maior deslocamento vertical do COM do que nas condições com o calçado biomimético e descalço. Conclusão Os achados deste trabalho reafirmam que o uso do calçado influencia a marcha de crianças, especificamente na fase de desenvolvimento da marcha mas, que calçados com um design biomimético tem menores impactos no padrão de marcha das crianças.

Vertical stiffness and lower limb inter-joint coordination in older versus younger runners.

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 (Kvert) 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 Kvert between groups at each running speed. Watson's U2 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 Kvert 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.

Effects of Resistance Training of Upper Limb and Trunk Muscles on Soccer Instep Kick Kinematics.

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.

Runners with a history of shank and foot injury: Interactions among local musculoskeletal factors, age, and running experience.

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.

Ankle Sprain in Young Athletes: A 2-Year Retrospective Study at a Multisport Club.

Objective The present study aimed to analyze ankle sprains in young athletes of basketball, futsal, artistic gymnastics, trampoline, tennis, judo, and volleyball over 2 seasons. Methods Data of 529 athletes in the 1 st year and of 495 athletes in the 2 nd year of analysis were investigated from the injury record database of a sports club. The following data were considered: the demographic characteristics (age, body mass, height, and sex), the mechanism (contact or noncontact), the severity, the moment at which the injury occurred, and the recurrence. Also, the incidence rate, the injury risk of the first ankle sprain, and the incidence rate ratio between sports were calculated. Results The athletes sustained 124 ankle sprains in the 2 years of analysis. The majority occurred during training (76.6%) and lead to absence from sports practice (75.8%). The injury recurrence was low: 2 athletes (1.6%) had a recurrence in the same year and 5 (4.0%) in the following year. The incidence rate (0.79 to 12.81 per 1,000 hours) and the injury risk (1.14 to 19.44%) varied among sports. Volleyball, basketball, and futsal presented the highest injury rate incidence. Tennis, gymnastics, and trampoline showed the lowest injury rate incidence. Judo showed an incidence rate different from those of basketball and volleyball in the 1 st year and similar to those of other sports in the 2 nd year. Conclusion Ankle sprain greatly impacted sports practice and presented characteristics that differ among the investigated sports. These findings may contribute to developing preventive injury programs.

Ankle Sprain in Young Athletes: A 2-Year Retrospective Study at a Multisport Club / Entorse no tornozelo em jovens atletas: Um estudo retrospectivo de 2 anos em um clube multiesportivo

Abstract Objective The present study aimed to analyze ankle sprains in young athletes of basketball, futsal, artistic gymnastics, trampoline, tennis, judo, and volleyball over 2 seasons. Methods Data of 529 athletes in the 1st year and of 495 athletes in the 2nd year of analysis were investigated from the injury record database of a sports club. The following data were considered: the demographic characteristics (age, body mass, height, and sex), the mechanism (contact or noncontact), the severity, the moment at which the injury occurred, and the recurrence. Also, the incidence rate, the injury risk of the first ankle sprain, and the incidence rate ratio between sports were calculated. Results The athletes sustained 124 ankle sprains in the 2 years of analysis. The majority occurred during training (76.6%) and lead to absence from sports practice (75.8%). The injury recurrence was low: 2 athletes (1.6%) had a recurrence in the same year and 5 (4.0%) in the following year. The incidence rate (0.79 to 12.81 per 1,000 hours) and the injury risk (1.14 to 19.44%) varied among sports. Volleyball, basketball, and futsal presented the highest injury rate incidence. Tennis, gymnastics, and trampoline showed the lowest injury rate incidence. Judo showed an incidence rate different from those of basketball and volleyball in the 1st year and similar to those of other sports in the 2nd year. Conclusion Ankle sprain greatly impacted sports practice and presented characteristics that differ among the investigated sports. These findings may contribute to developing preventive injury programs.

Resumo Objetivo O presente estudo teve como objetivo analisar entorses no tornozelo em jovens atletas de basquete, futsal, ginástica artística, trampolim, tênis, judô e vôlei ao longo de duas temporadas. Métodos Foram investigados dados de 529 atletas no 1° ano e 495 atletas no 2° ano de análise a partir do banco de dados de registros de lesões de um clube esportivo. Foram considerados os seguintes dados: as características demográficas (idade, massa corporal, altura e sexo), o mecanismo (contato ou não contato), a severidade, o momento em que ocorreu a lesão e a recorrência. Além disso, foram calculadas a taxa de incidência, o risco de lesão da primeira entorse no tornozelo e a razão da taxa de incidência entre os esportes. Resultados Os atletas sofreram 124 entorses no tornozelo nos 2 anos de análise. A maioria ocorreu durante o treinamento (76,6%) e levou à interrupção da prática esportiva (75,8%). A recorrência da lesão foi baixa: 2 atletas (1,6%) tiveram recorrência no mesmo ano e 5 (4,0%) no ano seguinte. A taxa de incidência (0,79 a 12,81 por 1.000 horas) e o risco de lesão (1,14 a 19,44%) variaram entre os esportes. Vôlei, basquete e futsal apresentaram a maior incidência de lesões. Tênis, ginástica e trampolim apresentaram a menor incidência de lesões. O judô apresentou uma taxa de incidência diferente das do basquete e do vôlei no 1° ano e semelhante às dos outros esportes no 2° ano. Conclusão A entorse no tornozelo impactou muito a prática esportiva e apresentou características que diferem entre os esportes investigados. Esses achados podem contribuir para o desenvolvimento de programas de prevenção de lesões.

Dynamic knee valgus prevalence in children and its association with pain intensity, foot mobility, and sex- A cross-sectional study.

Introduction: Knee pain can impact the performance of activities and sports participation in children. Dynamic knee valgus is a movement pattern commonly related to health conditions that may be associated with sex and foot kinematics in children. Objective: To assess the prevalence of dynamic knee valgus and its relationship with foot mobility, sex, and knee pain in children. Method: A cross-sectional observational study was carried out with 144 children (10-18 years old). The pain level was investigated using the Visual Analog Pain Scale and categorized into no pain/minor pain (≤2 cm), moderate pain (3-4,9 cm), and severe pain (≥5.0 cm). Foot mobility was assessed using the adapted navicular drop test and categorized into poor/adequate foot mobility (0.0 cm-0.9 cm) and greater foot mobility (≥1.0 cm). The dynamic knee valgus presence was checked using the step-down test. The association analysis was performed using simple tabulation considering the cluster effect. The Prevalence Ratios and the respective confidence intervals (95%) were estimated from Multiple Poisson Regression with robust variance. A significance level of 5% was adopted. Results: The dynamic knee valgus prevalence was 26.3% and 26.9% in the right and left lower limbs, respectively. Females presented greater dynamic knee valgus frequency in the left lower limb than males. The dynamic knee valgus presence in males was associated with foot mobility in right (p = 0.001) (Prevalence Ratio: 9.33 Confidence Interval: 2.93-29.72) and left lower limbs (p = 0.003) (Prevalence Ratio: 6.25 Confidence Interval: 1.7-22.62). Conclusion: Male and female children showed different relationships of the analyzed factors, suggesting that characteristics related to sex may impact the aspects linked to dynamic knee in children.

A escolha do calçado por corredores amadores: caracterização e associação com o histórico de lesão auto reportada / La elección del calzado por los corredores aficionados: caracterización y asociación con el historial de lesiones autoinformado / Selection of running shoes by amateur runners: characterization and association with the self-reported history of injury

RESUMO O calçado é um elemento importante para a prática de corrida. As evidências sobre os impactos das características do calçado e de sua prescrição nas lesões de corredores são restritas. Dessa forma, os objetivos deste estudo foram investigar o processo de escolha do calçado por corredores e verificar se variáveis relacionadas ao calçado e seu processo de escolha estavam associadas à presença e recorrência de lesão no último ano. Foi realizado um estudo observacional com 254 corredores que responderam um questionário autoadministrado sobre características demográficas, a prática esportiva, o calçado e o processo de sua escolha, e lesões ocorridas nos últimos 12 meses. O teste qui-quadrado foi empregado para verificar se havia diferença na distribuição das respostas de cada questão, enquanto o teste de regressão logística para verificar se as variáveis relacionadas ao calçado e ao processo de escolha predizem a presença e recorrência de lesão no último ano. Os resultados indicaram que a maioria dos corredores possui tênis específico para a prática esportiva e considera algumas características ao adquiri-lo, como o amortecimento intermediário e a diferença na altura do solado entre a parte posterior e a anterior de aproximadamente 10mm. A maioria indica conhecer seu tipo de pisada, mas não a considera na escolha do calçado. Além disso, a maioria não usa palmilha e não recebeu orientação para a escolha do calçado. O modelo obtido com a regressão não foi significativo. Assim, apesar de os corredores considerarem as características do calçado ao adquiri-lo, essas características e o processo de escolha não foram associados à presença e recorrência de lesão nos últimos 12 meses.

RESUMEN El calzado es un elemento importante para la práctica deportiva de carrera. Sin embargo, es limitada la evidencia sobre los impactos de las características del calzado deportivo y su prescripción sobre las lesiones en los corredores. Por lo tanto, los objetivos de este estudio fueron investigar el proceso de elección de calzado por los corredores y verificar si las variables relacionadas con el calzado y su proceso de elección se asociaron con la presencia y recurrencia de lesiones en el último año. Se realizó un estudio observacional con 254 corredores que respondieron un cuestionario autoinformado sobre las características demográficas, la práctica deportiva, el calzado y el proceso de elección, y las lesiones que se llevaron a cabo en los últimos 12 meses. La prueba de chi-cuadrado se aplicó para verificar la existencia de diferencias en la distribución de respuestas para cada pregunta. Y se utilizó la prueba de regresión logística para determinar si las variables relacionadas con el calzado y su proceso de elección pueden predecir la presencia y recurrencia de lesiones en el último año. Los resultados indicaron que la mayoría de los corredores tienen zapatillas adecuadas para hacer deporte y consideran algunas características a la hora de adquirirlas, como una amortiguación intermedia y la diferencia de altura de la suela entre la parte delantera y la trasera de aproximadamente 10mm. La mayoría afirma conocer el tipo de paso, pero no lo considera a la hora de elegir el calzado. Además, la mayoría no utiliza plantillas y no recibe orientación sobre la elección del calzado. El modelo que se obtuvo con la regresión no fue significativo. Por lo tanto, aunque los corredores tienen en cuenta las características del calzado a la hora de adquirirlo, esas características y el proceso de elección no se asociaron con la presencia y recurrencia de lesión en los últimos 12 meses.

ABSTRACT Running shoes are an essential element for sports practice. Evidence on the effect of the shoe characteristics and prescription in running injuries are scarce. Thus, this study aimed to investigate runners's process of choosing running shoes and to verify whether the variables related to running shoes and their selection process are associated with the presence and recurrence of injuries in the previous year. An observational study was conducted with 254 runners who answered a self-reported questionnaire about demographics, sports practice, shoe characteristics and selection criteria, and injuries in the last 12 months. The chi-square test evaluated whether there was a difference in the distribution of answers to each question. The logistic regression evaluated whether the variables related to shoes and selection criteria predicted injury's presence and recurrence in the previous year. The results showed that most runners had specific shoes for sports practice and considered some characteristics of the shoes to choose them, including intermediate cushioning and a difference in the heel-to-toe drop of approximately 10mm. Most respondents indicated knowing their foot type but not considering it when choosing shoes. Besides, most individuals did not use foot orthotics and did not receive guidance to select their shoes. The model obtained with the regression was not significant. Therefore, despite considering shoe characteristics when choosing it, these features and the selection criteria were not associated with the presence and recurrence of injuries in the previous 12 months.

Lower limb inter-joint coordination patterns are associated with walking experience in toddlers according to limb and stance periods.

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.

The Influence of the Shoe over the Medial Foot Arch and the Lower Limbs Kinematics in Toddlers.

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.

Perfil de lesões em praticantes de CrossFit®: prevalência e fatores associados durante um ano de prática esportiva / Perfil de lesiones en practicantes de CrossFit ®: prevalencia y factores asociados durante un año de práctica deportiva / Injury profile in CrossFit® practitioners: Prevalence and associated factors during a year of sports practice

RESUMO Este estudo teve como objetivo investigar a prevalência de lesões durante um ano em praticantes de CrossFit® e a influência das características da prática esportiva e demográficas nessas lesões. Foi realizado estudo de coorte retrospectivo com 180 praticantes de CrossFit®, que responderam a um questionário sobre: características demográficas (idade, massa corporal, altura e sexo), características da prática esportiva (tempo de prática esportiva, frequência e duração de treino, formação de carga e prática de outro esporte) e ocorrência e características da lesão (quantidade, região lesionada e estrutura acometida). Por meio do teste de Mann-Whitney U, investigou-se a diferença nas variáveis contínuas entre aqueles com e sem histórico de lesão. Utilizando o teste de qui-quadrado e o teste exato de Fisher, avaliou-se a associação entre variáveis categóricas e a presença ou não de lesão. O teste de qui-quadrado goodness-of-fit foi aplicado para investigar se a frequência observada de lesões por região do corpo e por tipo era diferente da esperada. A prevalência de lesão foi de 63%, e aqueles com histórico de lesão tinham menor tempo de prática esportiva. A presença de histórico de lesão foi associada a menor frequência semanal e diária e menor duração de treinos, assim como à formação de carga Scale. A frequência de lesão em perna, joelho, coluna lombar, ombro e punho, assim como do tipo músculo e tendão foi acima da esperada. As demais variáveis não apresentaram diferença entre grupos ou não foram associadas à presença de lesão. Logo, a maioria dos investigados relatou lesão que foi influenciada pelas características da prática esportiva, e não pelas demográficas.

RESUMEN Este estudio tuvo como objetivo investigar la prevalencia de lesiones en practicantes de CrossFit® durante un año y la influencia de las características deportivas y demográficas en estas lesiones. Se trata de estudio de cohorte retrospectivo, realizado con 180 practicantes de CrossFit®, quienes respondieron a un cuestionario que contenía: características demográficas (edad, masa corporal, altura y sexo), características de la práctica deportiva (tiempo de práctica deportiva, frecuencia y duración del entrenamiento, carga de entrenamiento y práctica de otro deporte) y ocurrencia y características de la lesión (cantidad, región lesionada y estructura afectada). Para el análisis de la diferencia en las variables continuas entre los practicantes con y sin antecedentes de lesiones, se utilizó la prueba U de Mann-Whitney. Se evaluó la asociación entre las variables categóricas y la presencia o ausencia de lesión mediante la prueba de chi-cuadrado y la prueba exacta de Fisher. La prueba de chi-cuadrado goodness-of-fit se aplicó para investigar si la frecuencia de lesiones por parte del cuerpo y por tipo era distinta de lo esperado. La prevalencia de lesión fue del 63%, y los practicantes con antecedente de lesión tenían menor tiempo de práctica deportiva. La presencia de antecedentes de lesión se asoció con una menor frecuencia semanal/diaria y una menor duración del entrenamiento, así como con la formación de la carga de Scale. La frecuencia de lesiones en la pierna, la rodilla, la columna lumbar, el hombro y la muñeca, así como de tipo muscular y tendinoso fue mayor a la esperada. Las demás variables no mostraron diferencia entre grupos o no se asociaron con la presencia de lesión. Por lo tanto, la mayoría de los participantes reportaron presentar una lesión que estuvo influenciada por las características de la práctica deportiva, y no por la demografía.

ABSTRACT This study aimed to investigate the prevalence of injuries in CrossFit® practitioners and the influence of sports practice and demographic characteristics on these injuries. A retrospective cohort study was carried out with 180 CrossFit® practitioners who answered a questionnaire with demographic characteristics (age, body mass, height, and sex), sports characteristics (number of years practicing CrossFit®; training frequency, duration, and training program; and practice of other sports), and presence of any injury suffered and its characteristics (number of injuries, region, and type of injury). The Mann-Whitney U test investigated the difference in continuous variables between those with and without injury history. The chi-square test and Fisher's exact test investigated the association between categorical variables and the presence or not of injury over the last year. The chi-square goodness-of-fit test investigated if the frequency of injuries per body location and type differed from the expected one. Injury prevalence was 63%. Participants with a history of injury showed a shorter time of CrossFit® practice. The presence of injury history was associated with lesser weekly and daily training frequency, shorter training duration, and Scale training program. The frequency of injuries on leg, knee, lumbar spine, shoulder, and wrist, and the muscle and tendon was greater than expected. The other variables were neither different between groups nor associated with injury presence. Thus, most participants presented injury over the last year, influenced by the sports characteristics but not by demographic characteristics.

The Influence of the Shoe over the Medial Foot Arch and the Lower Limbs Kinematics in Toddlers / A influência de calçados no arco longitudinal medial do pé e na cinemática dos membros inferiores de crianças no início da fase de aquisição de marcha

Abstract 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.

Resumo Objetivo Avaliar o comportamento do arco longitudinal medial do pé (ALM) e os parâmetros cinemáticos dos membros inferiores durante a deambulação com calçados biomiméticos (CBs) e não biomiméticos (NB1, NB2, NB3 e NB4) em crianças no início da fase de aquisição da marcha. Métodos Foram avaliadas quatro crianças no início da fase de aquisição da marcha nas seguintes condições: andar descalço, andar com CBs e calçados NB1, NB2, NB3 e NB4 em solo plano. O calçado biomimético é descrito como biomimético por emular pisos naturais e irregulares por meio de uma palmilha interna dinâmica. O ALM e a cinemática do quadril, joelho e tornozelo durante a marcha foram avaliados por meio de sistema de análise do movimento tridimensional. A similaridade entre as curvas cinemáticas das condições descalça e com calçado foi analisada por meio do cálculo de root mean square error (RMSE). Resultados O CB foi o que apresentou maior magnitude do ALM e maior diferença do ALM em relação à condição descalça (maior RMSE). O CB apresentou ainda menor diferença na cinemática das articulações do joelho e tornozelo durante a marcha quando comparado à condição descalça (menor RMSE). O calçado NB2 apresentou a cinemática do quadril mais semelhante à condição descalça (menor RMSE). Conclusão Os calçados CB e NB2 que apresentam a região do antepé mais larga geraram menores diferenças na cinemática dos membros inferiores. Além disso, o ALM foi maior no CB provavelmente devido a seu design ser diferente daquele dos demais calçados.

Clinimetric properties of a postural assessment software in older people: reliability, standard error of measurement, and minimal detectable change / Propriedades clinimétricas do software de avaliação postural em idosos: reprodutibilidade, erro padrão da medida e mudança mínima detectável

Objective: To evaluate intra- and inter-rater reliability, standard error of the measurement (SEM), and minimal detectable change (MDC) of the angles obtained with a Postural Assessment Software (SAPO) in older people. Methods: Postural evaluation of 32 older adults was performed using Postural Assessment Software (SAPO). Two raters performed the procedure independently, and one of the raters repeated the process 7 to 10 days later. Reliability was assessed through the intraclass correlation coefficient (ICC) and paired and independent t-tests. SEM and MDC95 values were calculated, and Bland-Altman plots were generated. Results: The inter-rater analysis showed that the raters were not different in any of the angles. Most angles achieved good to excellent inter-rater reliability (ICC = 0.34 ­ 0.81) and intrarater reliability (ICC = 0.33 ­ 0.88) and were not different between days. The SEM was lower than 10º in most angles. The MDC95 ranged from 2.88º to 18.49º. Bland-Altman analysis indicated that most angles were within the limits of agreement. Overall, angles generated in lateral view had better reliability properties. Conclusion: Postural Assessment Software (SAPO) showed angles with distinct reliability properties in older adults. Angles that reached good to excellent intra- and inter-reliability and exhibited lower variability could be considered for assessing postural changes in older adults. MDC95 values could be used as a reference for indicating changes greater than the variability of the measurement.

Objetivo: Avaliar a confiabilidade interexaminador, o erro padrão da medida (EPM) e a mudança mínima detectável (MMD) dos ângulos obtidos com Software para Avaliação Postural (SAPO) em pessoas idosas. Metodologia: Foi realizada a avaliação postural de 32 idosos usando o Software para Avaliação Postural (SAPO). Dois avaliadores executaram o procedimento independentemente, e um deles repetiu o processo sete a dez dias depois. A confiabilidade foi avaliada pelo coeficiente de correlação intraclasse (CCI) e testes t pareados e independentes. Os valores de EPM e MMD95 foram calculados e os gráficos de Bland-Altman foram gerados. Resultados: A análise de interexaminador mostrou que os resultados entre os examinadores não foram diferentes em qualquer dos ângulos. A maioria dos ângulos atingiu confiabilidade inter (CCI = 0,34 ­ 0,81) e intraexaminador (CCI = 0,33 ­ 0,88) de boa a excelente e não houve diferença entre os dias. O EPM foi menor que 10º na maioria dos ângulos. A MMD95 variou de 2,88º a 18,49º. A análise de Bland-Altman demonstrou que a maioria dos ângulos estava nos limites de concordância. Os ângulos gerados na vista lateral obtiveram melhores propriedades de medida. Conclusões: O Software para Avaliação Postural (SAPO) mostrou ângulos com diferentes propriedades de medida em pessoas idosas. Os ângulos que atingiram boa a excelente confiabilidade intra e interexaminadores e baixa variabilidade poderiam ser considerados para avaliar as mudanças posturais em pessoas idosas. Os valores de MMD95 podem ser usados como referência para indicar mudanças maiores que a variabilidade da medida.

Prevalence and Factors Associated with Pain and History of Musculoskeletal Injuries in Skateboarders.

Objective (a) To identify the prevalence of current musculoskeletal pain and injury in the last year and (b) to verify the association of the presence of current pain and the history of injury with demographic, sports, and health characteristics in skateboarders. Method A cross-sectional observational study was conducted with 64 skateboarders who answered a questionnaire addressing demographic, sports practice, and health characteristics. The Fisher exact test verified the association of these characteristics with the presence of current pain and with the report of injury in the last year. The chi-squared test verified whether there was a difference between the observed and expected distribution for the body segment reported with pain and history of injury, and with the type of injury. Results The prevalence of pain was of 82.8%, and the observed frequency was higher than expected ( p < 0.01) in the knee, the ankle, the lumbosacral region, and the foot. The presence of pain was associated with age ( p = 0.05) and with whether the patient had already undergone physical therapy treatment ( p < 0.01). The prevalence of injury in the last year was of 68.8%, and the frequency observed was higher than expected ( p < 0.01) in the knee, the ankle, the wrist, the hand, the foot, and the shoulder. Sprain and fracture showed a higher frequency than expected ( p < 0.01). The history of injury was associated with the use of protective equipment ( p = 0.01), having already undergone surgery ( p = 0.02), and physical therapy treatment ( p = 0.03). Conclusion The practice of skateboarding presents a high prevalence of pain and injuries in the last year. The findings may contribute to the planning of preventive strategies.

The Effects of Knee Flexion on Tennis Serve Performance of Intermediate Level Tennis Players.

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 use of Horizon graphs to visualize bilateral biomechanical time-series of multiple joints.

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.

Runners with a history of injury have greater lower limb movement regularity than runners without a history of injury.

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.

Measurement Properties and Translation to Brazilian-Portuguese of the Challenge for Children and Adolescents with Cerebral Palsy.

Aims: Translate the Challenge assessment into Brazilian-Portuguese, determine its face validity, evaluate the reliability of the total score and score per item, investigate whether the child's gross motor level (classified by the Gross Motor Function Classification System-GMFCS) influences the reliability levels, and estimate responsiveness to change.Methods: The translation followed four stages: translation, synthesis, back-translation, and review. For face validity, ten physical therapists evaluated item relevance. Children and adolescents with cerebral palsy (n = 50, 5-18 years of age) GMFCS I and II were evaluated by two therapists for inter and intra-rater reliability. Thirty of these participants were recruited for the instrument's responsiveness evaluation and reassessed (n = 28) after three months of treatment. Minimal Detectable Change (MDC), and Minimal Clinically Important Difference (MCID) were estimated.Results: The back-translated version was similar to the English version. All test items were considered relevant by the physical therapists. Total score intra and inter-rater reliability were excellent for both GMFCS levels (ICC = 0.94-0.99). Items' intra- and inter- rater reliability varied from low to almost perfect (kw=-0.14-0.94). MDC90 and MDC95 values were 3.90-6.35 and 4.63-7.54, respectively. MCID values were 3.57-4.56.Conclusion: The translated version of the Challenge showed excellent face validity and reliability and was able to document longitudinal change.