Along the way I will throw in a #protip for each day that can be used in your every day refereeing, all the way to the international level..
Lesson 1: Measure all the balls
The Laws Of The Game (LOTG) require balls to be inflated within a particular range. In fact there are several requirement for a ball to be used in a match, they are:
The ball is:
• spherical (note this is different from round)
• made of leather or other suitable material
• of a circumference of not more than 70 cm (28 ins) and not less than 68 cm (27 ins)
• not more than 450 g (16 oz) and not less than 410 g (14 oz) in weight at the start of the match
• of a pressure equal to 0.6 – 1.1 atmosphere (600 – 1,100 g/cm2 ) at sea level (8.5 lbs/sq in – 15.6 lbs/sq in)
Additionally for any match connected to FIFA, a ball must additionally bear:
• the official “FIFA APPROVED” logo
• the official “FIFA INSPECTED” logo
• the “INTERNATIONAL MATCHBALL STANDARD” logo
There are a few noteworthy things in here:
- This describes a "size 5" ball used for U-14 and above play in the US. A smaller size ball, does not match these requirements.
- There is both a weight and a pressure requirement for the ball.
- Pressure variability is very large, while the weight variability is not.
- FIFA has a substantial program around this can can be found here.
Before each match, every single ball should be checked that will come into play. A gauge such as this one from Official Sports do nicely even for large amounts of balls. You can get far less expensive ones that will do the trick in a pinch too. With the very large variability of pressure, most balls will fall within the range will little or no adjustments.
Balls outside these ranges can substantially affect play given the range. A ball on the lower end will act and feel flat and on the upper end no one will want to strike as it is so hard.
Note that the "Charmin Test" of squeezing the ball does not work in all cases and can provide incorrect result, especially with balls that are made of a hard plastic or are overinflated.
Once you get the pressure dialed in, you should be set for the match.
Here are a couple of #protips that I have used late in my refereeing career.
- Give both keepers the chance to handle the match ball before the match, best at the introductions so they won't go far. They will appreciate the touch before the match.
- Remember a ball is SPHERICAL, not round as the distinction is huge. It has also made its way on to National Referee exams.
- What Law 2 does not cover is the most important aspect of the ball ... that it be safe. If a ball hurts a player (from a loose panel or similar) or if there is a large consensus to change the ball, just change it. It is a small thing that can get you big points with players. Remember, its their game ... let them use the (legal) ball they want.