The HUMAC360 is a small box that offers big results. Measuring 4” x 4” x 4” and weighing just 4 pounds, the HUMAC360 attaches to any patient or exercise equipment in seconds, using a 16’ retractable nylon belt. When the belt is pulled the HUMAC Software reports velocity, distance, and if a weight is recorded, power. These functional parameters are displayed on the screen for proper pacing and distance and in reports for evidence based rehabilitation. It could not be easier.Read the Full Story
Wrist movements do not originate from a single joint. The radius articulates with three of the carple bones (known collectively as the rdiocarple joint) which in turn articulate with each other and the next row of bones (known as the intercarple joints). This allows for flexion and extension (as well as radial and ulna deviation and the combination of all four motions circumduction).
These movements can be performed in either the standing, or seated (most popular) position. Most movements around the wrist in everyday life, and in fact sport, occur with the hand free in space (open chain). The position of the wrist joint moves in space in relation to the elbow which makes the two joints co-dependant. The action of flexion of the elbow also calls into play the wrist as stabilisation is required for the flexor muscles to function correctly.
The most popular position for testing and offers the greatest range of motion. This was the original position of choice for research as the wrist could be more easily stabilized (eventually a V shaped stabiliser was developed to stabilise without altering muscle function). The forearm should be supinated for this test. Stabilisation of the upper body with the chest straps often does not limit the motion of the shooulder during the test. The elbow muscles need to be active to resist the pull of the biceps (isometrically). This action is minimal for extension but will often become much greater in flexion. This motion should be discouraged. The arm should be placed at 25 degrees abduction with 90 degrees elbow flexion. Best for research and patient populations.
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As above but with much less stabilisation.
Seated: in the seated position stabilisation usually involves chest straps, an elbow pad and an elbow strap
Standing: Stabilisation in the standing position is normally just the forearm pad.
The hand grip is always used and should be placed in the neutral position (see seated above) for any test.
Axis of rotation:
The axis of rotation is often difficult. It is actually slightly oblique through the wrist just distal to the tubercle of the radius and the head of the ulna (opposite the styloid process)
With the wrist parallel to the forearm (see standing position above).
Range of motion:
Although it may be possible to go to extreme extension and flexion. An appropriate range of motion at the wrist would be between 40 degrees extension and 60 degrees flexion.
Is necessary, however, a counter balance may be provided to accomplish this.
As velocities in some sports (any involving throwing an object) are known to reach thousands of degrees/second (Pappas et al., 1985) testing using a dynamometer has been said to be non-functional. However, speeds over 300 degrees/second have been found to be difficult to achieve by even baseball pitchers (Cook et al., 1987). This could be said to suggest that muscular effort starts the motion but only occurs at slower speeds with momentum and acceleration playing a larger role later in the speed of the motion later through range rather than pure strength. Even if this speed could be achieved it is over such a small arc that the results gained would likely be fruitless.
Generally it is accepted that speeds of 60 degrees/second and multiples of this should be used.
|Speed/s||60 or 120||60 or 120||60-300||60-500|
|Sets||3||3||4||up to 9|
|Speed/s||60 up to 180||60 up to 120||60-300|
|Sets||6||6||up to 12|
In the wrist it is normal to look at the ratio between the right and left sides there should be a 0-10% difference between the sides. Anything beyond this would either demonstrate extreme hand dominance (this can happen in certain sports like javelin), or indicate a muscle imbalance which would be best corrected.
Eccentric results are generally 30% higher than concentric within the same muscle Ivey et al (1985) Davies (1984).
Generally the extensors are stronger than the flexors by 30% however results do ary between 100% stronger to 25% weaker
The angle of peak torque for the flexors is 19 degrees and is at 14 degrees for extension (Stefanska 2006).
|Stephanska (2006)||Age||Sex||Machine||PT NM (SD)||PT NM (SD)|
|60||10.8 (2.2)||18.2 (4.2)|
|120||10.2 (2.1)||17.1 (4)|
|Ber et al (1985)||20||F||Flex/ext ratio|
|60 Non Dominant||0.86|
|Flexion PT ftlbs||Extension PT ftlbs|
Nicholas et al. (1989)