Mechanical output from individual muscles during explosive leg extensions: The role of biarticular muscles

Jacobs, Ron; Bobbert, Maarten F.; Schenau, G.J. van Ingen

doi:10.1016/0021-9290(95)00067-4

Cited by 270 publications

(193 citation statements)

References 19 publications

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“…A 'lumped' muscle model in the form of a linear actuator represented all the muscles responsible for a particular joint's flexion and a similar muscle model was used for extension ( Figure 1b) (Mills et al, 2008). This allowed the linear actuator to act with a moment arm scaled to the subject from the middle of the ranges found in Duda et al (1996) and Jacobs et al (1996).…”

Section: Methodsmentioning

confidence: 99%

Reducing ground reaction forces in gymnastics’ landings may increase internal loading

Mills

Pain

Yeadon

2009

Journal of Biomechanics

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Section: Methodsmentioning

confidence: 99%

Reducing ground reaction forces in gymnastics’ landings may increase internal loading

Mills

Pain

Yeadon

2009

Journal of Biomechanics

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“…A rotational elastic component with a stiffness value of 465 Nm.rad -1 was included in series with the torque generator at the ankle joint. This stiffness value was based upon an elastic element of length 0.314 m in the muscletendon complex of the tricep-surae muscle group with a moment arm of 0.046 m (Jacobs et al, 1996) and a maximum stretch of the elastic element of 4% at maximum torque (Bobbert and van Ingen Schenau, 1990). The FORTRAN code implementing the model was generated using the Autolev software package which is based on Kane's method of formulating the equations of motion (Kane and Levinson, 1985).…”

Section: Methodsmentioning

confidence: 99%

Maximising somersault rotation in tumbling

King

Yeadon

2004

Journal of Biomechanics

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Performing complex somersaulting skills during the flight phase of tumbling requires the generation of linear and angular momenta during the approach and takeoff phases. This paper investigates how approach characteristics and takeoff technique affect performance with a view to maximising somersault rotation in tumbling. A five-segment planar simulation model, customised to an elite gymnast, was used to produce a simulation which closely matched a recorded performance of a double layout somersault by the elite gymnast. Three optimisations were carried out to maximise somersault rotation with different sets of initial conditions. Using the same initial linear and angular momentum as the double layout somersault and varying the joint torque activation timings allowed a double straight somersault to be performed with 19% more rotation potential than the actual performance. Increasing the approach velocity to a realistic maximum of 7 ms -1 resulted in a 42% reduction in rotation potential when the activation timings were unchanged but allowed a triple layout somersault to be performed with an increase of 31% in rotation potential when activation timings were re-optimised. Increasing also the initial angular momentum to a realistic maximum resulted in a 4% reduction in rotation potential when the activation timings were unchanged but allowed a triple straight somersault to be performed with a further increase of 9% in rotation potential when activation timings were re-optimised. It is concluded that the limiting factor to maximising somersault rotation is the ability to generate high linear and angular velocities during the approach phase coupled with the ability to adopt consonant activation timings during the takeoff phase.

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“…That is, the joints of the prostheses can either store or dissipate energy, but cannot provide net power over a gait cycle. The inability to deliver joint power significantly impairs the ability of these prostheses to restore many locomotive functions, including walking up stairs and up slopes, running, and jumping, all of which require significant net positive power at the knee joint, ankle joint or both (Winter and Sienko 1988;DeVita et al 1996;Jacobs et al 1996;Prilutsky et al 1996;Nagano et al 1998;Riener et al 1999;Nadeau et al 2003). Furthermore, although less obvious, even biomechanically normal walking requires positive power output at the knee joint and significant net positive power output at the ankle joint (Winter 1991).…”

Section: Motivationmentioning

confidence: 99%

Design and Control of a Powered Transfemoral Prosthesis

Sup

Bohara

Goldfarb

2008

The International Journal of Robotics Research

506

370

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The paper describes the design and control of a transfemoral prosthesis with powered knee and ankle joints. The initial prototype is a pneumatically actuated powered-tethered device, which is intended to serve as a laboratory test bed for a subsequent self-powered version. The prosthesis design is described, including its kinematic optimization and the design of a three-axis socket load cell that measures the forces and moments of interaction between the socket and prosthesis. A gait controller is proposed based on the use of passive impedance functions that coordinates the motion of the prosthesis with the user during level walking. The control approach is implemented on the prosthesis prototype and experimental results are shown that demonstrate the promise of the active prosthesis and control approach in restoring fully powered level walking to the user.

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Mechanical output from individual muscles during explosive leg extensions: The role of biarticular muscles

Cited by 270 publications

References 19 publications

Reducing ground reaction forces in gymnastics’ landings may increase internal loading

Reducing ground reaction forces in gymnastics’ landings may increase internal loading

Maximising somersault rotation in tumbling

Design and Control of a Powered Transfemoral Prosthesis

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