Objectives: To compare the electrical activation of the rectus femoris (RF), long head of the biceps femoris (BF) and semitendinosus (ST) and the resistance torque (T R ) of the hip extension (HE) movement performed on the Pilates Cadillac with the attachable spring in two different positions. Methods: Twelve subjects performed five hip extensions with the attachable spring in two positions (high and low). Electromyography (EMG) and electrogoniometry data were colleted simultaneously. The root mean square (RMS) was calculated and normalized based on the maximal voluntary contraction. A free-body diagram (FBD) and movement equations were used to calculate T R . One-way ANOVA was used to investigate EMG differences between spring positions (p<0.05). Results: When the spring was in the high position, T R was classified as descending and occurred in the "direction" of flexion over most of the range of motion (ROM). In the low position, T R descended until 60º of hip flexion, in the direction of flexion, and from there it took on an ascending pattern in the direction of extension. Conclusions: The EMG analysis seemed to follow the T R , with higher values for the RF in the low position and higher activation values for the BF and ST in the high position, where the external demand was greater. EMG and T R data supply complementary information for prescribing Pilates exercises.Key Words: torque; electromyography; Pilates; hip extension. ResumoObjetivos: Comparar a ativação elétrica do reto femoral (RF), do bíceps femoral cabeça longa (BF) e semitendíneo (ST) e o torque de resistência (T R ) do movimento de extensão de quadril (EQ) realizado com a mola fixada em duas posições distintas no Cadillac.Métodos: 12 sujeitos realizaram 5 repetições de EQ com a mola fixada em duas posições (alta e baixa). Dados de eletromiografia (EMG) e eletrogoniometria foram coletados simultaneamente. O root mean square foi calculado e normalizado com base na contração voluntária máxima. Para o cálculo do T R , foram usados diagramas de corpo livre (DCL) e equações de movimento. ANOVA one-way foi usada para verificar as diferenças para EMG entre as posições de mola (p<0,05). Resultados: Com a mola fixa na posição alta, o T R foi classificado como decrescente e ocorreu no "sentido" de flexão na maior parte da amplitude de movimento (ADM). Para posição baixa, o T R foi descrescente até 60º de flexão de quadril no sentido de flexão e, a partir daí, assumiu um comportamento crescente no sentido da extensão. Conclusões: A análise EMG pareceu acompanhar o T R , apresentando valores maiores para o RF na posição baixa e maiores valores de ativação para o BF e ST na posição alta, onde a demanda externa foi maior. Dados de EMG e T R fornecem informações complementares para prescrição de exercícios no Pilates.Palavras-chave: torque; eletromiografia; Pilates; extensão do quadril.

| Schoolbag weight and mode of carrying it can contribute to postural deviations and back pain. Therefore, our objective was to determine and compare, among the school grades and between sexes, the schoolbag weight relative to body weight and the mode of carrying it of Elementary School students, who leave their books on

The understanding of swimming propulsion is a key factor in the improvement of performance in this sport. Propulsive forces have been quantified under steady conditions since the 1970s, but actual swimming involves unsteady conditions. Thus, the purpose of the present article was to review the effects of unsteady conditions on swimming propulsion based on studies that have compared steady and unsteady conditions while exploring their methods, their limitations and their results, as well as encouraging new studies based on the findings of this systematic review. A multiple database search was performed, and only those studies that met all eligibility criteria were included. Six studies that compared steady and unsteady conditions using physical experiments or numerical simulations were selected. The selected studies verified the effects of one or more factors that characterise a condition as unsteady on the propulsive forces. Consequently, much research is necessary to understand the effect of each individual variable that characterises a condition as unsteady on swimming propulsion, as well as the effects of these variables as a whole on swimming propulsion.