Knee and ankle joint torque–angle relationships of multi-joint leg extension

Hahn, Daniel; Olvermann, Matthias; Richtberg, Jan; Seiberl, Wolfgang; Schwirtz, Ansgar

doi:10.1016/j.jbiomech.2011.05.011

Cited by 44 publications

(45 citation statements)

References 47 publications

(58 reference statements)

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“…Scientific examination of these activities is more complicated than studying isometric exercises (meaning the body does not move) because the movement kinetics continually change in response to adjustments in body joint angles (2,15,20). For example, maximal force and torque constantly change during the deadlift exercise as the lifter moves from the starting (barbell on the floor) to the finish position (hips fully extended) (2,15). This explains why force production during a dynamic isotonic exercise is at its greatest during the portion of the movement that places the body in optimal positions and joint angle (2,29,32).…”

Section: Introductionmentioning

confidence: 99%

Acute Effects of Elastic Bands on Kinetic Characteristics During the Deadlift at Moderate and Heavy Loads

Galpin

Malyszek

Davis

et al. 2015

Journal of Strength and Conditioning Research

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Loading a barbell with variable resistance positively alters kinetic characteristics during the back squat and bench press but has never been studied during the deadlift. The purpose of this project was to examine the acute effects of combining elastic bands and free weights during the deadlift at moderate and heavy loads. Twelve trained men (age: 24.08 ± 2.35 years, height: 175.94 ± 5.38 cm, mass: 85.58 ± 12.49 kg, deadlift 1 repetition maximum (RM): 188.64 ± 16.13 kg) completed 2 variable resistance (B1 and B2) and 1 traditional free-weight (NB) condition at both 60 and 85% 1RM on a force plate. B1 had 15% resistance from bands, with the remaining 85% from free weights. B2 had 35% bands and 65% free weights. NB used free weights only. Average resistance was equated for all conditions. Power and velocity generally increased, whereas force decreased with the addition of bands. The amount of band tension (B1 or B2) had little impact on power when lifting at 60% 1RM. However, greater resistance from bands resulted in greater peak and relative power when lifting at 85% 1RM. Adding elastic bands decreased time to peak force (PF), time between PF and peak power (PP), and time between PF and peak velocity (PV) when compared with NB at 60% 1RM (NB > B1 > B2). These differences only reached significance for NB > B2 when lifting at 85% 1RM. These same differences existed for time between PP and PV. Thus, the amount of tension from bands has less impact on interpeak variables at heavier absolute loads. Practitioners should consider using heavy bands when prescribing the deadlift for speed or power, but not maximal force.

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Section: Introductionmentioning

confidence: 99%

Acute Effects of Elastic Bands on Kinetic Characteristics During the Deadlift at Moderate and Heavy Loads

Galpin

Malyszek

Davis

et al. 2015

Journal of Strength and Conditioning Research

View full text Add to dashboard Cite

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“…The dependence of joint torque on joint angle is well known and studied for the single and multijoint cases. The dependency in a single joint is due to muscle physiology and several models exist [50] whereas multijoint interdependencies could be due to muscle-on-muscle impingement and intermuscular force transmission [51]. From observation of our data, some relationships between joint positions, velocities, and accelerations can be observed for certain joints (see Table I).…”

Section: Acceleration Modelmentioning

confidence: 68%

Overapproximative Human Arm Occupancy Prediction for Collision Avoidance

Pereira

Althoff

2018

IEEE Trans. Automat. Sci. Eng.

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Abstract-Predicting the occupancy of a human in real time is of great interest in human-robot coexistence for obtaining regions that a robot should avoid in safe motion planning. The human body is composed of joints and links, suiting approximation by a kinematic chain, but the control strategy of the human is completely unknown, meaning the potential occupancy grows very fast and it is difficult to compute tightly in real time. As such, most previous work considers only specific, known, or probable movements, and usually does not account for a range of human dimensions. Focusing on the human arm, we analyze archetypal movements performed by test subjects to create a dynamic model. Motion-capture data of subjects are fitted, for modeling purposes, to two abstractions: a 4-degree of freedom (DOF) model and a 3-DOF model, to obtain dynamic parameters. We validate our approach on movements from a publicly available database. The prediction is shown to be computationally fast, and reachable sets of the abstraction are shown to enclose all possible future occupancies of the arm for different subjects, tightly but overapproximatively. The 3-DOF model has advantages over the 4-DOF in terms of speed, though the 4-DOF model is tighter at smaller time horizons. Such an overapproximative representation is intended for certifiable safety-guaranteed collision avoidance algorithms for robots.Note to Practitioners-Motivated by the need to keep humans safe when working alongside robots, our earlier work proposes a method of trajectory planning where the robot certifies each movement as safe before it performs it. For this to prove that unsafe collisions cannot occur, an overapproximative prediction of the human is needed, meaning that no possible future position of the human is outside the predicted region, or reachable occupancy. However, making this prediction both small enough (so that it does not include unreachable regions) and fast enough for real-time use is not straightforward. We find the limits of human motion by asking a range of test subjects to perform movements as fast as possible. We calculate the reachable occupancies based on these limits and show that our predictions are indeed overapproximative, fast, and not wasteful of volume. One can then use the aforementioned approach to guarantee safety; future challenges are reliably sensing the human's pose and implementing our approach on an industrial robot.

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“…Adicionalmente, Salles et al 21 , demonstraram maior desempenho em saltos com 90° de flexão do joelho em comparação com menores flexões (50 e 70°). Hahn et al 22 , demonstraram que em atividades multiarticulares, o pico de torque interno produzido na articulação do joelho aproxima-se dos 50° de flexão, além de que as técnicas DJ135 e DJ135A necessitam de maior tempo para a transição entre as fases excêntrica e concêntrica e afetam negativamente o CAE pela dissipação de energia 4 . Para o pico de impacto (normalizado pelo peso corporal) a técnica BDJ apresentou valores significantemente maiores quando comparados às técnicas DJ90 e DJ135.…”

Section: Discussionunclassified

Técnicas de aterrissagem afetam o desempenho e estresse mecânico durante Drop Jump

Marchetti

Santos

Soares

et al. 2017

Rev Bras Med Esporte

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Introdução: O drop jump é utilizado para melhorar da potência dos membros inferiores. Mantendo-se a altura de queda constante, a variação da técnica de aterrissagem pode alterar o desempenho e as características mecânicas do salto. Objetivo: Avaliar os efeitos da alteração da técnica de aterrisagem no desempenho e na força de reação do componente vertical do solo após drop jump. Métodos: Vinte e cinco homens saudáveis e fisicamente ativos (idade: 26±8 anos, massa corporal total: 75±10 kg, altura: 175±10 cm) realizaram quatro técnicas de aterrisagem após o drop jump: bounce drop jump (BDJ), drop jump com 90° de flexão do joelho (DJ90), drop jump com 135° de flexão do joelho (DJ135) e drop jump com 135° de flexão do joelho e com apoio das mãos no solo (DJ135A). Foram realizadas três tentativas para cada técnica, os sujeitos realizaram o drop jump caindo de uma plataforma de força de 40 cm de altura. As medidas de altura de salto, tempo de contato e impacto foram determinadas através da força de reação do componente vertical do solo, medida pela plataforma de força, em frequência de aquisição de 2.000 Hz. A ANOVA com medidas repetidas foi utilizada para comparar as diferentes técnicas. Resultados: A técnica BDJ apresentou menor altura de salto, menor tempo de contato e maior impacto que as demais condições (P < 0,001). A técnica DJ90 apresentou altura de salto similar às condições DJ135 e DJ135A e tempo de contato menor que as condições DJ135 e DJ135A, além de menor impacto que as demais condições (P < 0,001). Conclusão: As maiores alturas do salto vertical foram observadas para DJ90, DJ135 e DJ135A. O menor tempo de contato foi observado na técnica BDJ, seguido de DJ90. Quanto ao impacto, a técnica BDJ apresentou os maiores valores.Descritores: desempenho atlético; força muscular; fenômenos biomecânicos. ABSTRACT Introduction: The drop jump is used to improve the power of the lower limbs. Keeping the drop height constant, the variation of the landing

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Knee and ankle joint torque–angle relationships of multi-joint leg extension

Cited by 44 publications

References 47 publications

Acute Effects of Elastic Bands on Kinetic Characteristics During the Deadlift at Moderate and Heavy Loads

Acute Effects of Elastic Bands on Kinetic Characteristics During the Deadlift at Moderate and Heavy Loads

Overapproximative Human Arm Occupancy Prediction for Collision Avoidance

Técnicas de aterrissagem afetam o desempenho e estresse mecânico durante Drop Jump

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