Why do footballers need power?

Mass-Energy is constant. If you are working then you are doing it spending energy. If you have a working rate so u also have a energy spending rate, which is called the power. As footballers working rate is too high (running, kicking, jumping, tackling, defensing etc) their energy spending rate i. e, required power is also high. Hence to be a footballer you need high power.

Power is required for footballers because they has to run long distances in the field, they have to kick, and have to be very quick. So, they require high power.