Abstract Gait analysis may offer information to choose the best exercise-based clinical intervention for the children with clubfoot. However, other motor abilities are not commonly investigated. The aim of this research was to analyze the biomechanics of countermovement vertical jumping in clubfooted children who had undergone surgery. Fourteen children with idiopathic clubfoot were selected and the control group consisted of 11 children. Clubfooted children showed less dorsiflexion in the jump preparation phase. In the impulse phase, this group showed more knee flexion and less plantarflexion associated with less magnitude of vertical reaction force and less muscular activity in the gastrocnemius medialis. In the landing phase, for clubfoot group, we found high loading rate for the first peak of vertical force, less plantarflexion and more knee flexion. Understanding the biomechanical changes of vertical jump landing should assist in better targeting of physical and sporting activities of this population.

O objectivo do estudo se pautou em determinar as características de parâmetros das forças de reacção do solo (FRS) em movimentos típicos do basquetebol executados por jogadores profissionais. Também se objectivou determinar correlações entre o desempenho nos saltos e sua carga mecânica durante as aterrissagens. Oito atletas realizaram cinco tentativas em seis movimentos: arremesso em suspensão (jump), salto com contramovimento (jump & reach), bandeja, rebote e corrida com bola rápida (v=6m/s) e lenta (v=4m/s). Os parâmetros dinâmicos da FRS foram colectados através de uma plataforma de força (KISTLER AG 9287). Os resultados do primeiro pico da força vertical na aterrissagem, do tempo para o para o pico e do impulso foram: no jump 4,54 ± 1,10 PC, 0,08 ± 0,01s, 0,13 ± 0,04 PC.s; no rebote 5,39 ± 1,26 PC, 0,07 ± 0,01s, 0,18 ± 0,04 PC.s; e na bandeja 7,27 ± 2,71 PC, 0,08 ± 0,13 s, 0,24 ± 0,04 PC.s. Os resultados evidenciam que o aparelho locomotor é submetido a uma carga mecânica relativamente alta durante os movimentos. As baixas correlações entre o desempenho do salto e o primeiro pico da força vertical na aterrissagem (0,44 no jump; 0.22 no rebote; e 0.34 na bandeja) sugerem que o desempenho do salto não tem influência determinante na carga gerada.

The purpose of this study was to evaluate dynamical parameters of the ground reaction force (GRF) in specific basketball movements performed by Brazilian professional players. It was also aimed to determine correlations between jump performance and its impact shock during landings. Eight athletes performed 5 trials in each movement: jump shot, jump and reach, layup, rebound and dribble at two different speeds (control: v=4m/s and speed: v=6m/s). Dynamical parameters of GRF were sampled by a force platform (KISTLER AG 9287). Results of the first peak of vertical force in landing, peak rise time and impulse were, respectively: in jump shot 4.54 ± 1.10 BW, 0.08 ± 0.01s, and 0.13 ± 0.04 BW.s; in rebound 5.39 ± 1.26 BW, 0.07 ± 0.01s, and 0.18 ± 0.04 BW.s; and in layup 7.27 ± 2.71 BW, 0.08 ± 0.13 s, and 0.24 ± 0.04 BW.s. These results showed that the player´s body is submitted to a relatively high impact shock during basketball movements. The low correlations between jump high and the first peak of vertical force (r=0.44 in jump shot, r=0.22 in rebound, and r=0.34 in layup) demonstrated that jump performance did not have a relevant influence on impact shock during landings.

Tendo em vista a escassa produção científica com enfoques biológicos sobre a Capoeira, o objetivo deste estudo foi realizar a análise dinâmica de movimentos selecionados da capoeira no âmbito da Força de Reação do Solo (FRS). A amostra constituiu-se de 10 capoeiristas, os quais realizaram sobre uma plataforma de força 4 diferentes movimentos: "Negativa Fechada", "Martelo", "Armada Pulada" e "Parafuso". A análise das curvas de FRS centrou-se: na Força Vertical Máxima (Fy máx), no Tempo até o Pico de Fy máx (TFy máx), no Gradiente de Crescimento de Fy (GC Fy) e no Impulso gerado por Fy nos primeiros 50ms de execução dos movimentos (I50). Refletindo o comportamento da Fy(max) e do T Fy (max), os menores valores para o GC Fy e para o I50 foram obtidos na "Negativa Fechada" (4,91±4,69 PC·s-1; 1,53 ±0,76·10-2 kg·ms) e no "Martelo" (2,61±1,70 PC·s-1; 0,84 ±0,41·10-2 kg·ms), enquanto a "Armada Pulada" (115,93±79,84 PC·s-1; 7,54 ±3,04·10-2 kg·ms) e o "Parafuso" (69,17±65,68 PC·s-1; 6,38±2,88·10-2 kg·ms) apresentaram os maiores valores para estas variáveis. O presente estudo traz evidências de que, pelo menos no âmbito das forças externas, a "Negativa Fechada" e o "Martelo" podem ser inseridos nas fases iniciais do programa de treinamento, ao passo que, o "Parafuso" e a "Armada Pulada", movimentos cujas exigências mecânicas e motoras são maiores, poderiam ser inseridos posteriormente no programa de treinamento. Porém, a interpretação dos resultados exige cautela, uma vez que a sobrecarga mecânica recebida depende essencialmente das condições mecânicas das estruturas osteomioarticulares dos praticantes, bem como do nível de condicionamento físico destes.

Considering the limited scientific information concerning a biological focus on "Capoeira", the aim of this study was to conduct a dynamic analysis of selected movements of "Capoeira" in the scope of Ground Reaction Force (GRF). The sample consisted of 10 "capoeiristas". All of them performed the following movements: "Negativa Fechada", "Martelo", "Armada Pulada" and "Parafuso" in a Force Plate. The analysis of the GRF curves was centered in the Maximum Vertical Force (Fy max), in the Time to achieve Fy max Peak (TFy max), in the Vertical Force Growth Rate (GR Fy) and in the Impulse generated for Fy in first 50ms of movement execution (I50). Reflecting the behaviour of Fy(max) and TFy(max), the smaller values for GR Fy and I50 were obtained by "Negativa Fechada" (4,91±4,69 PC·s-1 ; 1,53±0,76·10-2 kg.ms) and by "Martelo" (2,61±1,70 PC·s-1; 0,84±0,41·10-2 kg.ms), while the "Armada Pulada" (115,93±79,84 PC·s-1; 7,54±3,04·10-2 kg·ms) and "Parafuso" (69,17±65,68 PC·s-1; 6,38±2,88·10-2 kg·ms) showed the major values for these variables. The present study brings evidences that, at least in the scope of external forces, the "Negativa Fechada" and "Martelo" could be inserted in the initial phases of training program, whereas the "Parafuso" and "Armada Pulada", movements whose mechanical and motor demands are greater, could be approached later in the same program. However, a cautionary note should be present in these results since the received overload depends not only of the osteomioarticular structures conditions of the practiser, but also of their level of physical conditioning.