Classification of Activities in Day to day life

Activities are classified as light, moderate, or heavy according to the energy expended or the oxygen consumed while accomplishing them.

Light work for the average male (65 kg) requires 2.0 to 4.9 kcal/min, or 6.1 to 15.2 mL O2/kg per minute, or 1.6 to 3.9 METs. Strolling 1.6 km/hr, or 1.0 mph, is considered light work.

Heavy work for the average male (65 kg) requires 7.5 to 9.9 kcal/min, or 23.0 to 30.6 mL O2/kg per minute, or 6.0 to 7.9 METs. Jogging 8.0 km/hr, or 5.0 mph, requires 25 to 28 mL O2/kg per minute and is considered heavy work. The energy expended is equivalent to 8 to 10 kcal/min, or 7 to 8 METs.

The energy expenditure necessary for most industrial jobs requires more than three times the energy expenditure at rest. Energy expenditure of certain physical activities can vary, depending on factors such as skill, pace, and fitness level.

The average individual engaged in normal daily tasks expends 1800 to 3000 kcal per day. Athletes engaged in intense training can use more than 10,000 kcal per day.

 What is Energy Expenditure in Physiotherapy? 

Energy is consumed and is mostly represented in kilocalories by people involved in physical activity. By evaluating the energy cost, behaviors can be categorized as light , moderate, or heavy. Mechanical performance and body mass influence the energy cost of any operation. Terrain, stride length, and air resistance are variables that influence both walking and running. Energy expended is computed from the amount of oxygen consumed. Units used to quantify energy expenditure are kilocalories and METs.

•  A kilocalorie is a Represents the energy value of food taken by person. It is the amount of heat necessary to raise 1 kilogram (kg) of water 1˚C. A kilocalorie (kcal) can be expressed in oxygen equivalents. Five kilocalories equal approximately 1 liter of oxygen consumed (5 kcal = 1 liter O2).
•  A MET is defined as the oxygen consumed (milliliters) per kilogram of body weight per minute (mL/kg). It is equal to approximately 3.5 mL/kg per minute.

What is Workout Efficiency? How its measures?

Efficiency is usually expressed as a percentage,

Percent efficiency = useful work output/energy expended or work input × 100

Work output equals force times distance (W = F × D). It can be expressed in power units or work per unit of time (P = w/t). 

On a treadmill, work equals the weight of the subject times the vertical distance the subject is raised walking up the incline of the treadmill. On a bicycle ergometer, work equals the distance (which is the circumference of the flywheel times the number of revolutions) times the bicycle resistance. 

Work input equals energy expenditure and is expressed as the net oxygen consumption per unit of time. In aerobic exercise, the resting volume of oxygen used per unit of time (VO2 value) is subtracted from the oxygen consumed during 1 minute of the steady-state period. 

The Steady state is reached within 3 to 4 minutes after exercise has started if the load or resistance is kept constant. In the steady-state period, VO2 remains at a constant (steady) value.