The hand must be somewhat concave to increase the contact surface with the hand.

Gloves are very important when you carry out a task

Bending the wrist in flexion direction should be prevented by

Hand held tools must not be heavy, if the tool cannot rest on a surface and is normally used with one hand, its weight should exceed 2 kg.

Motorized hand held tools can reduce the body

The position of the hands and the elbow should be well above the shoulder level during carrying out the task.

When the subject needs to work in a level above the shoulder level

working with the hands behind the body should be avoided.

Sitting down is better for any subject to perform a fine manipulative task.

The overall static muscular workload required to lock the joints of foots,knees, hips and spine is reduced.

Energy consumption is greatly reduced during standing

Sitting is better than standing in circulation

Sitting is more stabile posture which might help to carry out tasks requiring fine or precise motion.

The sitting drawbacks

- Proper body mechanics can achieved by

Mechanically there is always balance between internal muscular forces and external gravitational pull.

The balance is achieved in proper postural alignment and produced optimum pressure distribution over the spinal structures and intervertebral discs.

Work place design includes

if the subject sits on a chair with 90 degrees backrest inclination, the trunk will move.......... , the subject will lean the trunk .......

The load on the intervertebral disc increases to 140% : 200%