Ergonomics

Ergonomics is the study and design of work places, products and systems to fit people who use them. It is the study of the often-complex inter-relationship between people and their occupational, domestic and leisure activities (Hayne, 1984). It is the science devoted to the search for and creation of the best possible conditions of employment so as to eliminate harm, boredom and fatigue of labour (Snork, Iruine and Bass, 1970).
The six manual material handling tasks include; lifting, lowering, pushing, pulling, carrying and walking: these as established by studies, are responsible for most occupational injuries (Astrad and Rodali, 1986, Garg and Sexena, 1986). Spine is the most vulnerable as a result of the injuries (Nwuga, 1990).
Most furniture and equipment found in our homes, offices, recreation centers, vehicles, etc, are beautifully designed but fail to conform to the basic biomechanics of normal posture and consequently compel its user to assume or develop poor postural habits.
It is recommended that the angle of inclination between the backrest and the seat of a working chair be 90 degrees-110 degrees and for a high-backed chair, comfortable when it is between 104 degrees and 110 degrees (Hayne, 1984). Any sitting without backrest or support has been discovered to place a load of 100kg on the lumber spine as to the 70kg in a standing posture of an individual of 70kg body weight (Nachemson, 1975).