Dance
Home > Dance > Core > Performance > Dance Technique incorporating safe dance practice
Dance Technique incorporating safe dance practice
Performing sequences relative to anatomical structure
Individual differences
Muscle function
Muscle fibres attach either directly to a bone, or to a tendon which is fixed to a bone. The force produced by the contraction of the muscle fibres is transmitted to the bone by the tendon. The nature of muscles is that they can produce force in only one direction, i.e. they can only pull, not push. Joints are generally two-directional because of the actions of opposing sets of muscles called agonists and antagonists. The antagonists should relax when the agonists contract. Muscles play different roles in the production of a given action. Prime movers are mainly responsible for the movement; synergists are two or more muscles which perform an identical action at a joint; assistors contribute to the action, and stabilisers control a certain segment or part, so the action can take place.
For example, when extending the leg forwards, the quadriceps is the prime mover, or agonist muscle. Its attachment on the femur is stabilised by muscles of the hip. The hamstrings, tendons attached to several muscles which have the opposite action to the quadriceps, begin to contract as the leg picks up momentum to control the extension. The contraction of these muscles, which are called antagonists muscles, is maximal at the end of the movement to stop and control it.
While there are three general types of muscle, cardiac, smooth and striated (or voluntary) muscle, the dancer is principally concerned with striated muscle, which provides movement and stabilisation.
Usually a muscle shortens when it contracts. Muscles contract as a result of the activation of nerve structures called motor units. The strength of the contraction depends on the number of motor units that are activated. The selective activation of specific motor units may be the primary factor that allows for the remarkably fine isolations of movement called for in dance.
Muscle contraction has three aspects: neurological, mechanical and chemical. The chemical reaction involves the release of energy in either the presence or absence of oxygen. Aerobic activity is lower intensity and occurs in the presence of oxygen. Anaerobic activity is high-intensity and occurs in the absence of oxygen. The dancer will call on both energy systems during training, rehearsal and performance, depending on the nature of the work undertaken.
The stretch reflex is s fundamental function of the neuromuscular system. When a muscle is stretched, there is a reflexive contraction of that muscle following the stretch. The stretch reflex can be utilised to advantage in movement skills, which incorporate a wind-up or back swing. The plie is actually the dancer’s wind-up for a jump. But as a protective mechanism that protects overstretching of a muscle, it can prevent the achievement of gains in flexibility. To block the stretch reflex, conscious control from higher centres of the brain is needed to sustain a long stretch.
Striated (voluntary) muscle fibres come as two types: “white” or fast-twitch, and “red” or slow-twitch. Deep, stabilising muscles tend to have high proportions of red fibres, while superficial, moving muscles have higher proportions of white fibres.
There are three basic types of contraction:
|
Concentric, |
where the muscle contracts and shortens
e.g lateral tilt |
|---|---|
|
Eccentric, |
where the muscle contracts and
lengthens e.g. plie, landing in a jump |
|
Isometric, |
where the muscle contracts and its
length remains the same e.g holding a balance. |
The eccentric contraction has a role in resisting gravity, and this can be used to advantage in terms of shock absorption and control over the transfer of weight. On the other hand, eccentric contraction can inhibit the “effect” of releasing the weight and giving in to gravity that is a feature of some modern dance techniques.
The web sites Steven Lewis 
and HMS Beagles provide interactive information on the muscular system as well as further links to additional anatomical web sites.
Back to The muscular system
Back to Individual differences
Back to Dance Technique incorporating safe dance practice
|