What is Vo2 Max or maximal oxygen consumption, maximal oxygen uptake, aerobic capacity?

Vo2Max determines the cardiovacular fitness of an individual. it is the volume of oxygen used by the muscles for contraction in a unit of time.
The muscles need energy for contraction, with the help of oxygen and few other elements energy(ATP) is created. This energy feuls muscle contraction. in short, the better the supply of oxygen to the muscle longer will the activity last.
Oxygen reaches the body via the Lungs, the lungs pass it on to the blood and the heart pumps it all around the body.
Oxygen is supplied to the muscle by blood vessels, the muscles extract the oxygen from the blood vessels and use it to create energy needed for muscular movement.

This phenomenon of providing and extracting oxygen to the muscle is the Vo2max = V - volume per time, O2 - oxygen, max - maximum.

It is essential for any athlete to have a high Vo2Max, whatever the sport. The Vo2Max is a indirect indicator of the individuals overall health. It is a standard for measuring physical fitness.
In endurance sports the greater the Vo2Max the longer and faster the sportsperson will perform.
In strength sports if the individual has a high Vo2Max then the formation of harmful chemicals or metabolites(lactic acid) is minimal and the sportsperson can maintain a set for longer duration for max strength gains.

High Protein diets and calcium

Precautions while on a high protein diet.

• Protein, water and calcium: When on a high protein diet, take care of the water input as high protein diet is known to cause increase concentration of calcium in urine. 
• Habitual excess protein intake is a significant risk factor for calcium loss via the kidneys. Calcium excretion also accompanied with daily urinary excretion of urea. The calcium excretion with animal protein intake was found to be significantly positive in both sexes and in each age group whereas that with plant protein was not. Findings suggest that regular use of excess protein in diets may augment calcium excretion in the urine, at least in the elderly.
• Sports persons especially bodybuilders control their water input when they are near the competition date, and they increase their protein intake at the same time, this may lead to excess excretion of calcium.
• Plenty of water, regular physical activity (30 minutes walking, more than 5 days a week) and monitoring kidney profile should prevent any adverse effects.