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Dafne Pires Pinto, Pedro Vieira Sarmet Moreira, and Luciano Luporini Menegaldo

subject remained in a single-leg stance above one force plate. For the volunteers who chose left-leg support, pelvis and lumbar spine rotations had their angular positions inverted, except for the sagittal plane, such that their data could be comparable with right-leg subjects. Quiet standing posture

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Swati Shenoy and Alexander S. Aruin

The objective of this study was to determine if a forward-tilted seat and the resultant semi-kneeling body position associated with sitting on the Balans Multi Chair (BMC) affect postural control in sitting. Nine healthy subjects were seated on either the BMC or a regular (REG) chair with their arms extended. They were instructed to induce self-initiated body perturbations in four different directions by exerting brief pulses of force against a stationary frame positioned in front of them. Electromyographic (EMG) activities of trunk and leg muscles were recorded before and during the perturbations. The results show that sitting on both types of chairs was associated with anticipatory activation of trunk and upper leg muscles. In contrast, anticipatory activation of distal muscles was observed while sitting only on the REG chair and was absent while sitting on the BMC. The outcome of the study suggests that although the forward-tilting seat and semi-kneeling body position might help in preserving a normal lordosis, it is not associated with anticipatory activation of lower leg muscles, which might reduce the ability of an individual to counteract self-initiated body perturbations. These findings stress the important role of chair designs in the control of sitting posture.

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Timothy J. Gibbons and Marie-Louise Bird

as more comfortable than the foam roller which may influence exercise enjoyment and adherence. Practical Applications (1) Exercises in supine with bilateral leg support should precede unilateral leg supported exercises in the progression of core stability tasks. (2) To progress in abdominal muscle

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Ilha G. Fernandes, Matheus A. Souza, Matheus L. Oliveira, Bianca Miarka, Michelle A. Barbosa, Andreia C. Queiroz, and Alexandre C. Barbosa

during such an unbalanced task may enhance the knowledge about strategies to reduce the incidence of falls with increasing age. Therefore, the present study aimed to compare the acute effects on balance of single versus double leg support during isometric PAP contraction until task failure. Methods

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Cristina Cabrejas, Jose Morales, Mónica Solana-Tramunt, Ainhoa Nieto-Guisado, Alesander Badiola-Zabala, and Josep Campos-Rius

–experimental) on each of the dependent variables. The dependent variables correspond to the total area and the MV AP and MV ML in the standard right and left single-leg support conditions, with open eyes and closed eyes. In addition, the variables dependent on the postural control of total area and the MV AP

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William C. Whiting, Robert J. Gregor, and Marie Halushka

Eight male javelin throwers were filmed while throwing new-rules javelins during competition at five meets over a 2-year period. Body segment kinematics and javelin release parameters were assessed relative to their contribution to throwing performance. The data suggest that successful throws, as judged by distance thrown, are characterized by higher release speeds, longer last-step lengths, less flexion of the front-leg knee during the final plant phase, and an orderly progression of peak speeds at the hip, shoulder, and elbow from the onset of double leg support until release. Individual variability in performance was associated with differences measured between several throwing variables. Limitations inherent to two-dimensional analysis were identified that highlighted the need for three-dimensional investigation of the javelin throw.

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Nicholas H. Yang, Paul K. Canavan, and Hamid Nayeb-Hashemi

Subject-specific models were developed and finite element analysis was performed to observe the effect of the frontal plane tibiofemoral angle on the normal stress, Tresca shear stress and normal strain at the surface of the knee cartilage. Finite element models were created for three subjects with different tibiofemoral angle and physiological loading conditions were defined from motion analysis and muscle force mathematical models to simulate static single-leg stance. The results showed that the greatest magnitude of the normal stress, Tresca shear stress and normal strain at the medial compartment was for the varus aligned individual. Considering the lateral knee compartment, the individual with valgus alignment had the largest stress and strain at the cartilage. The present investigation is the first known attempt to analyze the effects of tibiofemoral alignment during single-leg support on the contact variables of the cartilage at the knee joint. The method could be potentially used to help identify individuals most susceptible to osteoarthritis and to prescribe preventive measures.

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Rachel S. Johnson, Kendall H. Scott, and Robert C. Lynall

time spent in double-leg support ( F 1,19  = 42.459, P  < .001). Participants spent significantly more time in double-support stance during planned termination with a cognitive task ( P  < .001, mean difference = −2.590%, 95% CI, −3.418 to −1.760, d  = 1.1), unplanned termination without a cognitive

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George Sofianidis, Anna-Maria Dimitriou, and Vassilia Hatzitaki

one-leg stance. Considering that one-leg support capacity is directly related to the risk of falling during the one-leg supporting phase of the walking cycle, the present finding may have important implications in fall prevention. As a result of the exercise programs, significant changes on the

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Guilherme S. Nunes, Débora Faria Wolf, Daniel Augusto dos Santos, Marcos de Noronha, and Fábio Viadanna Serrão

of the shank (right and left), and on the calcaneus (right and left). All markers and clusters remained in place throughout the interventions. For the single-leg squat assessment, the participant was positioned on the force platform with single-leg support (on the lower limb under analysis), the