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: For an average male: the volume of air normally breathed in is about 500mL. An average human breathes 12-20 times per minute. So per minute, you breathe in about 6-10L of air. Per hour this would be 360-600L of air. But this is only an approximation. Source(s): http://en.wikipedia.org/wiki/Lung_volume...