The purpose of this paper is to review current knowledge concerning the long and triple jumps. Much has been learned over the past two decades biomechanics of sport and exercise mcginnis pdf download techniques in the long jump.
Many myths have been dispelled and many training practices have been altered as a result. In all of this, the techniques employed during the takeoff have received little attention. It is in this area that the most important developments are likely to take place in the next decade. In contrast with the long jump, satisfactory answers have yet to be obtained to even the most fundamental of questions about techniques in the triple jump. The triple jump is an experimental task with potential for use in studies of human locomotion, of visual perception and control, of the strength of biological materials and of the mechanisms of soft tissue injury. Check if you have access through your login credentials or your institution. 1993 Published by Elsevier Ltd.
Self-organisation and constraints combine to determine sports performance. The GUT provides a basis for integrating the subdisciplines of sports science. Key measurement and analysis issues associated with the implementation of the GUT are discussed. Sports performance is generally considered to be governed by a range of interacting physiological, biomechanical, and psychological variables, amongst others.
Despite sports performance being multi-factorial, however, the majority of performance-oriented sports science research has predominantly been monodisciplinary in nature, presumably due, at least in part, to the lack of a unifying theoretical framework required to integrate the various subdisciplines of sports science. A central tenet of this GUT is that, at both the intra- and inter-individual levels of analysis, patterns of coordination and control, which directly determine the performance outcome, emerge from the confluence of interacting organismic, environmental, and task constraints via the formation and self-organisation of coordinative structures. This GUT could also provide a scientifically rigorous basis for integrating the subdisciplines of sports science in applied sports science support programmes adopted by high-performance agencies and national governing bodies for various individual and team sports. Muscle action can be classified as being either voluntary or involuntary.
Cardiac and smooth muscles contract without conscious thought and are termed involuntary, whereas the skeletal muscles contract upon command. Skeletal muscles in turn can be divided into fast and slow twitch fibers. Though this postural control is generally maintained as an unconscious reflex, the muscles responsible react to conscious control like non-postural muscles. Unlike skeletal muscle, smooth muscle is not under conscious control. Striated muscle contracts and relaxes in short, intense bursts, whereas smooth muscle sustains longer or even near-permanent contractions. Slow twitch fibers contract for long periods of time but with little force. They contribute most to muscle strength and have greater potential for increase in mass.
A skeletal muscle fiber is surrounded by a plasma membrane called the sarcolemma, which contains sarcoplasm, the cytoplasm of muscle cells. A muscle fiber is composed of many fibrils, which give the cell its striated appearance. It also protects muscles from friction against other muscles and bones. Besides surrounding each fascicle, the perimysium is a pathway for nerves and the flow of blood within the muscle.
At each level of bundling, a collagenous membrane surrounds the bundle, and these membranes support muscle function both by resisting passive stretching of the tissue and by distributing forces applied to the muscle. The term “myofibril” should not be confused with “myofiber”, which is a simply another name for a muscle cell. The striated appearance of both skeletal and cardiac muscle results from the regular pattern of sarcomeres within their cells. Although both of these types of muscle contain sarcomeres, the fibers in cardiac muscle are typically branched to form a network. Bundles of muscle fibers, called fascicles, are covered by the perimysium.
Muscle fibers are covered by the endomysium. The gross anatomy of a muscle is the most important indicator of its role in the body. In most muscles, all the fibers are oriented in the same direction, running in a line from the origin to the insertion. However, In pennate muscles, the individual fibers are oriented at an angle relative to the line of action, attaching to the origin and insertion tendons at each end. Pennate muscles are usually found where their length change is less important than maximum force, such as the rectus femoris. For the legs, superficial muscles are shown in the anterior view while the posterior view shows both superficial and deep muscles.
The muscular system consists of all the muscles present in a single body. Myoblasts follow chemical signals to the appropriate locations, where they fuse into elongate skeletal muscle cells. Cardiac and smooth muscle contractions are stimulated by internal pacemaker cells which regularly contract, and propagate contractions to other muscle cells they are in contact with. When a sarcomere contracts, the Z lines move closer together, and the I band becomes smaller.