Estimation of Work Efficiency Work is accomplished by the expenditure of energy. When more work is done with the same energy expenditure or when a given amount of work is accomplished at a smaller energy cost, the efficiency of the performance is higher. Other factors which must be considered in an appraisal of the overall efficiency of performance include (1) the rate of work, (2) the load, (3) the duration of the work, (4) the quality of the work and (5) the speed of recovery following the work period. It is apparent that efficiency is a complex measurement involving many variables. If the influence on efficiency of a single variable is to be estimated, the other variables must be kept constant. Efficiency is expressed by the formula: "Work done" is usually expressed in terms of foot-pounds or Calories (1 Calorie = 3,086 foot-pounds). For example, if a man weighing 150 pounds climbs stairs to a height of 20 feet, he performs 20 - 150 = 3,000 foot-pounds of work. The "energy used" in performing muscular work is ordinarily expressed in terms of the liters of oxygen consumed or in terms of the equivalent value in Calories of heat energy (1 liter of oxygen is equivalent to 5 Calories). If the efficiency of work is to be calculated from the formula given above, the work done and the energy used must be expressed in terms of the same unit. Efficiency of Work Along a Horizontal Plane In many of the physical activities of man movement occurs along a horizontal plane. In this type of work the arms and legs are raised and lowered with each step while the trunk is propelled along a steady plane with only a slight rise and fall at each step. In horizontal movement the external work accomplished is rather small. Other factors which require the expenditure of energy, such as the overcoming of muscle viscosity, the inertia of the bony levers and external wind resistance, are practically impossible to measure. As a result of these complications, the efficiency of work along a horizontal plane is not usually expressed by the ratio of work done to energy used, but rather by a consideration of the energy requirement for the particular distance and at the particular speed. The lower the energy, the higher will be the efficiency.		Home Pace Motivation Measures of Endurance Computation of Dietary Requirement Work Efficiency Maximum Steady State Work Inefficiency of Anaerobic Work Estimation of Work Efficiency Efficiency of Grade Climbing Low Economy of Slow Work Maximum Rate of Work Levers of the Body Fatigue and Recovery General Fatigue Symptoms Anxiety State Organic Fatigue Cortical Motor and Sensory Centers Effect of Exercise on Mental Work Visual Fatigue Muscular Fatigue Fatigue Prevention and Recuperation