and insertions, that are contracting are getting closer together. This is what
people do when they lift weights and, as is obvious from that activity, this helps
to tone, strengthen and ‘build’ muscles. So we can usefully introduce
concentric isometric activities when we want to achieve increased strength and
tone (see Fig. 1.5).
In isotonic concentric contractions the effort of the contracting muscle is
resisted but not quite overcome. The movement is allowed to take place, with
effort. Should a group of muscles be weak, after disuse for example, and should
you wish to tone these up, you have a perfect tool in concentric isotonic
methods of muscle energy.
Now let us assume that the flexors of your arm (which bend your elbow) are
weak, for whatever reason. If your opposite hand were placed on your forearm
to partially restrain an attempt to bend your arm then, as they contracted, the
weak muscles would be working against a degree of resistance. By repeatedly
doing this, with variations in the degree of resistance applied, it would be
possible to strengthen the weak muscles.
A variation exists where an area is rapidly and repeatedly moved in a variety of
directions, while being partially resisted. This would produce a series of concentric
isotonic contractions, known as an isokinetic exercise. An example of this could
involve a weak ankle; while sitting with the affected leg resting across the other
knee, you could use your hands to restrain a forceful effort to put the ankle joint
through as full a range of movements as possible, in a short space of time (no
more than 5 seconds). This has a powerful toning effect on the whole joint.
and insertions, that are contracting are getting closer together. This is whatpeople do when they lift weights and, as is obvious from that activity, this helpsto tone, strengthen and ‘build’ muscles. So we can usefully introduceconcentric isometric activities when we want to achieve increased strength andtone (see Fig. 1.5).In isotonic concentric contractions the effort of the contracting muscle isresisted but not quite overcome. The movement is allowed to take place, witheffort. Should a group of muscles be weak, after disuse for example, and shouldyou wish to tone these up, you have a perfect tool in concentric isotonicmethods of muscle energy.Now let us assume that the flexors of your arm (which bend your elbow) areweak, for whatever reason. If your opposite hand were placed on your forearmto partially restrain an attempt to bend your arm then, as they contracted, theweak muscles would be working against a degree of resistance. By repeatedlydoing this, with variations in the degree of resistance applied, it would bepossible to strengthen the weak muscles.A variation exists where an area is rapidly and repeatedly moved in a variety ofdirections, while being partially resisted. This would produce a series of concentricisotonic contractions, known as an isokinetic exercise. An example of this couldinvolve a weak ankle; while sitting with the affected leg resting across the otherknee, you could use your hands to restrain a forceful effort to put the ankle jointthrough as full a range of movements as possible, in a short space of time (nomore than 5 seconds). This has a powerful toning effect on the whole joint.
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