The physical energy required for the performance of the task. The pace of work, the tools used and the position of the worker are among the factors affecting energy use in the household work.
Incorrect posture and inefficient use of efforts while performing the work will cause fatigue. Hazelton and Russell describe efficient use as the one that 1) uses only those muscles or parts of the body that are necessary to the operatio, and 2) uses those muscles or parts of the body that are best able to do the work. In lifting a heavy baby or a bag of groceries from the floor, stronger leg muscles can be utilized if a person bends the knees and hips. If the worker needs only at the hips, he or she is using weaker back muscles and is ignoring this principle of efficiency in body mechanics.
There are related principles that apply to weight and body movement. Lifted objects carried close to the middle of the body require less effort than if they are carried away from the body. Smooth, continues and rhythmic motions are less tiring than sudden, sharp changes in movement.
Participants