The referees need a very high level of fitness, as they have to run around for over 90 minutes, they need very good eyes as well and stamina to.
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I think a level of fitness you need is to do a lot of practical sports in order to be a qualified tennis lime umpire.
Referees are needed to see if the match is fairly played and to help if someone is injured.
Age, gender, fitness level, level of physical activity are the main contributors.
Around 18 would be a starting age for high level matches. But junior referees can learn the game. The reason most World Cup/ top league referees are quite old is because they need to prove themselves at every level before they move up.
To Be Very Honest I Dont Know
because you need to maintain a high level of stamina and performance throughout the game
You can measure your strengths and weaknesses in terms of your fitness level using measurable performance parameters such as the number of games you have won.
If you have that endurance you will be able to run fast for longer.
we need fitness so you dont gain alot of weight and we need fitness you can exercise and get fit.
http://www.everydayhealth.com/fitness/measuring-personal-fitness-level.aspx is a good website too look at to see how to measure your fitness level. There's information and tips on the website.
You need to be a generally healthy human being with an average fitness level. 100kg - 110kg need to be assessed on the day.