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In explosive movements involving the lower extremity elastic recoil and transportation of power from knee to ankle via m. gastrocnemius allow power output about the ankle to reach values over and above the maximum power output of the plantar flexors. The object of this study was to estimate the relative power and work contributions of these two mechanisms(More)
The purpose of this study was to gain more insight into the behavior of the muscle-tendon complex of human m. triceps surae in jumping. During one-legged vertical jumps of ten subjects ground reaction forces as well as cinematographic data were registered, and electromyograms were recorded from m. soleus and m. gastrocnemius. A model was developed of m.(More)
The overarm throw of 56 female handball players was analysed cinematographically. The time courses of the ball velocity, the force on the ball, the energy flow to the ball as well as the velocities of wrist, elbow and hip were calculated. The mean ball velocity at release was 17.2 m s-1. The major part (73%) of the work on the ball appeared to be done in(More)
The present study was designed to investigate for vertical jumping the relationships between muscle actions, movement pattern and jumping achievement. Ten skilled jumpers performed jumps with preparatory countermovement. Ground reaction forces and cinematographic data were recorded. In addition, myoelectric activity (EMG) was recorded from seven leg(More)
Actions of muscles that pass over more than one joint are mainly described with respect to movements in the joints that are crossed. In a previous study of push-off without plantar flexion it was shown that the transformation of knee angular velocity into translation of the body is constrained by the fact that velocity difference between hip and ankle has(More)
In isokinetic experiments on human subjects, conducted to determine moments that can be exerted about a joint at different angular velocities, joint rotation starts as soon as the moment increases above the resting level. This contraction history differs from the one in experiments on isolated muscle, where the force is allowed to increase to an isometric(More)
Electromechanical delay (EMD) values were obtained using a cross-correlation technique for a series of 14 repetitive submaximal dynamic isometric contractions of the vastus lateralis performed by five subjects. To avoid a phase lag, which is introduced with one-way filtering, the EMG was processed with a bi-directional application of a second-order(More)
The main result of this study is that biarticular leg muscles contribute significantly to the work done at joints, due to transfer of power during explosive leg extensions. In particular, a net power transfer was shown from hip to knee joint during jumping and sprinting. Seven elite athletes performed explosive one legged jump and spring push offs.(More)
In the literature, drop jumping is advocated as an effective exercise for athletes who prepare themselves for explosive activities. When executing drop jumps, different jumping techniques can be used. In this study, the influence of jumping technique on the biomechanics of jumping is investigated. Ten subjects executed drop jumps from a height of 20 cm and(More)
Hypotheses concerning the influence of changes in the design of the human musculoskeletal system on performance cannot be tested experimentally. Computer modelling and simulation provide a research methodology that does allow manipulation of the system's design. In the present study this methodology was used to test a recently formulated hypothesis(More)