Keep your leg at a 90-degree angle and your knee and foot at the same height. Avoid rotating your spine at any point during the exercise. Pause at the top for two seconds before lowering your knee to the floor. Repeat 15-25 times before performing the exercises with the other leg.
Inhaled air is about 20-percent oxygen. Exhaled air is about 15-percent oxygen. Therefore, about 5-percent of breathed air is consumed in each breath. That air is converted to carbon dioxide. So, as far as how much air is actually used, human beings take in about 550 liters of pure oxygen per day. A person who is exercising uses a lot more oxygen than that.
Best Answer: It really depends upon the person activeness and size. The average adult at rest inhales and exhales something like 7 or 8 liters (about one-fourth of a cubic foot) of air per minute. That totals something like 11,000 liters of air (388 cubic feet) in a day. The air that is inhaled is about 20-percent oxygen, and the air that is exhaled is about 15-percent oxygen, so about 5-percent of the volume of air is consumed in each breath and converted to carbon dioxide. Therefore, a human being uses about 550 liters of pure oxygen (19 cubic feet) per day. A person who is exercising obviously uses a lot more oxygen than that. You could determine how much air is moving through your lungs by exhaling into a plastic bag of known volume at each breath and seeing how long it takes to fill the bag..