AbstractIntroduction: Excessive load on the backpacks can lead to musculoskeletal injuries and gait alterations. The objective of this study was to analyze the electromyographic (EMG) activity in association to the kinematic during the stance and balance phases of gait performed with and without the use of the backpack. Methods Twelve volunteers have executed a gait cycle in 3 tasks: without the school backpack (SM), with a backpack with load equivalent to 10% (M10) and 20% (M20) of the body weight (BW). It was evaluated the ankle, knee and hip angular excursion (AE), linear displacement (LD) of the toe and ankle, knee, hip, shoulder, head and EMG activity of the tibialis anterior (TA), vastus medialis (VM), rectus abdominis (RA), gastrocnemius lateral (GL), biceps femoris (BF) and spinal erector (EE) muscles. Results In the LD in the stance phase there was an AP increase for the toe and ankle, hip and head (p<0.043). In the balance phase for VT (vertical) direction, the shoulder presented a smaller displacement as well as the toe, ankle, knee, hip, shoulder and head in the ML direction. In the AP direction, the toe displacement was smaller as well as the ankle (p < 0.038). The AE in both phases was smaller for the hip (p <0.006). In the balance phase the IEMG was higher for the RA (p = 0.034). Conclusion These results suggest that the transport of school backpacks with loads of more than 10%BW causes changes in the kinematic and in the muscular recruitment pattern.

INTRODUCTION: Cyclograms are gait analysis tools that characterize the geometric aspect of the pattern of locomotion. Cyclograms are angle-angle diagrams that are very useful for representing cyclic patterns such as walking. This study is based on the hypothesis that parameters extracted from hip-knee cyclograms of individuals walking on a treadmill with 0° and 5° slopes can be used to determine the age group and sex of the volunteers. METHODS: In total, 40 physically active healthy adult volunteers, 20 young people (10 of each gender) and 20 elderly (10 of each gender), were divided into 4 groups, and the average value of area (A), perimeter (P) and the ratio P/√A of cyclogram were calculated, as well as the speed and cadence. RESULTS: The young male (YM) speeds were higher than the elderly male (EM) speeds (p=0.00), and the young female (YF) speeds were higher than the elderly female (EF) speeds (p=0.00). No difference in speed was found between YM and YF (p=0.59) or between EM and EF (p=0.95). The parameters extracted directly from the cyclogram allowed us to distinguish the studied groups according to age group (p<0.05), especially with the treadmill inclined at 5°, but it was not enough to determine gender (p>0.51). CONCLUSION: The hypothesis was partially confirmed because parameters extracted from the hip-knee cyclograms could differentiate volunteers by age group but not gender.

OBJETIVO: Muitos instrumentos têm sido propostos para avaliar o joelho, tornando muitas vezes difícil a sua escolha. Entre esses instrumentos destacam-se as escalas Knee Injury and Osteoarthritis Outcome Score (KOS) e International Knee Documentation Committee (IKDC), mas ainda não é claro qual delas seria melhor para avaliar o joelho de portadores da síndrome da dor femoropatelar (SDFP). O objetivo deste estudo foi comparar as escalas de avaliação KOS e IKDC para verificar qual delas seria mais apropriada na identificação de acometimento nos portadores da SDFP. MÉTODOS: O estudo incluiu 31 portadores da SDFP, com idade entre 18 e 39 anos (24,29 ± 4,09), sendo 27 sujeitos do sexo feminino e quatro, do masculino. Todos os sujeitos foram submetidos às escalas KOS e IKDC em duas ocasiões. A segunda aplicação serviu como prova de confiabilidade (PCKOS e PCIKDEC). A análise de correlação estatística entre as duas escalas foi realizada com os testes de Spearman e Wilcoxon, considerando-se significativo p < 0,05. RESULTADOS: O teste de correlação de Spearman revelou forte correlação entre KOS e PCKOS (r = 0,99; p < 0,001) e IKDC e PCIKDC (r = 0,96; p < 0,001). Houve uma moderada correlação entre KOS e IKDC (r = 0,46; p < 0,01) e PCKOS e PCIKDC (r = 0,55; p < 0,002). O teste de Wilcoxon revelou diferença entre KOS e IKDC (p < 0,001) e entre PCKOS e PCIKDC (p < 0,001). Houve igualdade entre KOS e PCKOS (p > 0,10) e diferença entre IKDC e PCIKDC (p < 0,02). CONCLUSÃO: As escalas KOS e IKDC apresentaram-se confiáveis durante o processo de aplicação nos portadores da SDFP, recebendo a KOS a prova de maior confiabilidade quando comparada ao IKDC.

INTRODUCTION AND OBJECTIVE: Many instruments have been proposed for the knee assessment, making its choice often difficult. Among these instruments, we can mention the Knee Injury and Osteoarthritis Outcome Score (KOS) and the International Knee Documentation Committee (IKDC) scales; however, it is unclear which of them would be better to evaluate the knee of subjects with patellofemoral pain syndrome (PFPS). The objective of this study was to compare the KOS and IKDC scales evaluation to verify which of them would be more appropriate to identify impairment in patients with PFPS. METHODS: The study included 31 PFPS subjects, aged between 18 and 39 years (24.29 ± 4.09); 27 subjects were female and 4 were male. All subjects were submitted to KOS and IKDC scales on the two occasions. The second application served as reliability evidence (PCKOS and PCIKDC).The analysis of statistical correlation between the scales was done with the Spearman and Wilcoxon tests, considering significant p < 0.05. RESULTS: The Spearman correlation test presented strong correlation between KOS and PCKOS (r = 0.99, p < 0.001) and IKDC and PCIKDC (r = 0.96, p < 0.001). There was a weak correlation between KOS and IKDC (r = 0.46, p < 0.01) and PCKOS and PCIKDC (r = 0.55, p < 0.002). The Wilcoxon test revealed differences between KOS and IKDC (p < 0.001) and between PCKOS and PCIKDC (p < 0.001). There was equality between KOS and PCKOS (p > 0.10) and difference between IKDC and PCIKDC (p < 0.02). CONCLUSION: The KOS and IKDC scales were reliable during the application in patients with PFPS, where the KOS received greater reliability when compared to the IKDC.

OBJECTIVE: This study assessed the muscular activity during root canal preparation through kinematics, kinetics, and electromyography (EMG). MATERIAL AND METHODS: The operators prepared one canal with RaCe rotary instruments and another with Flexo-files. The kinematics of the major joints was reconstructed using an optoelectronic system and electromyographic responses of the flexor carpi radialis, extensor carpi radialis, brachioradialis, biceps brachii, triceps brachii, middle deltoid, and upper trapezius were recorded. The joint torques of the shoulder, elbow and wrist were calculated using inverse dynamics. In the kinematic analysis, angular movements of the wrist and elbow were classified as low risk factors for work-related musculoskeletal disorders. With respect to the shoulder, the classification was medium-risk. RESULTS: There was no significant difference revealed by the kinetic reports. The EMG results showed that for the middle deltoid and upper trapezius the rotary instrumentation elicited higher values. The flexor carpi radialis and extensor carpi radialis, as well as the brachioradialis showed a higher value with the manual method. CONCLUSION: The muscular recruitment for accomplishment of articular movements for root canal preparation with either the rotary or manual techniques is distinct. Nevertheless, the rotary instrument presented less difficulty in the generation of the joint torque in each articulation, thus, presenting a greater uniformity of joint torques.

O objetivo principal deste estudo foi quantificar a atividade muscular durante a realização de agachamento unipodal com variações na técnica. Oito voluntários saudáveis realizaram agachamentos associados a cinco tipos de posição do pé: posição neutra, sobre cunha com 10º de declive, sobre cunha com 10º de aclive, sobre cunha com 10º de inclinação medial e sobre cunha com 10º de inclinação lateral. Foram avaliados os dados eletromiográficos dos músculos vasto medial oblíquo, vasto lateral, reto femoral, bíceps femoral, gastrocnêmio lateral e tibial anterior, utilizando a ANOVA fator único. O valor eletromiográfico integrado de todos os músculos não foi estatisticamente diferente nos cinco tipos de posição do pé. Os resultados deste estudo sugerem que diferentes tipos de posicionamento do pé durante o agachamento unipodal não provocam alterações no padrão de recrutamento muscular.

The specific aim of this study was to quantify muscle activity while performing squat with technique variations. Eight healthy volunteers performed squats under 5 types of foot positions: neutral position, under a 10º descending wedge, under a 10º ascending wedge, under a 10º medial wedge and under a 10º lateral wedge. It was evaluated electromyographic data of vastus medialis oblique, vastus lateralis, rectus femoris, biceps femoris, lateral gastrocnemius and tibialis anterior muscles, using One-Way ANOVA. The EMG integrated values was not significantly different across the 5 foot positions. The results of this study suggest that different foot positions during one-legged squat do not cause changes in muscle recruitment.

El objetivo principal de este estudio ha sido cuantificar la actividad muscular durante la realización de agachamiento unipodal con variaciones en la técnica. Ocho voluntarios saludables realizaron agachamientos asociados a cinco tipos de posición del pie: posición neutra, sobre cuña con 10º de declive, sobre cuña con 10º de elevación, sobre cuña con 10º de inclinación media y sobre cuña con 10º de inclinación lateral. Fueron evaluados los datos electromiográficos de los músculos vasto medial oblicuo, vasto lateral, recto femoral, bíceps femoral, gastrocnemio lateral y tibial anterior, utilizando ANOVA factor único. El valor electromiográfico integrado de todos los músculos no fue estadísticamente diferente en los cinco tipos de posición del pie. Los resultados de este estudio sugieren que diferentes tipos de posicionamiento del pie durante el proceso de agachamiento unipodal no provocan alteraciones en el padrón de reclutamiento muscular.