I got an email recently from Jack asking for some help.

"I need to explain why it is important to have fitness in cricket. I have some idea, but it is the specifics that are more troublesome. For example, you need strength to bowl fast, but how and why? You also need suppleness, but again why do you need suppleness to bowl fast. Obviously fast bowling is just one area, there is batting and fielding. Hopefully you can understand where I'm coming from."

Jack had broken 'fitness' into 4 terms: Speed, Strength, Suppleness and Stamina. It's a little bit limited but it's a useful model. So for Jack, let's define those terms in a cricketing sense.

• Speed is the ability to move at the greatest possible velocity. It might be running a quick single, chasing a ball in the outfield (whole body speed), throwing and bowling fast (arm speed) or playing aggressive shots while batting (bat speed). It's also reaction speed which is very important in batting and bowling.
• Strength is the ability to express force. This can be broken down into more specific types (maximum, elastic, endurance). In cricket it is closely tied to speed as many movements require both strength and speed working together (batting, bowling, diving to catch a ball). Strength also provides stability for muscles and joints and therefore has a role injury prevention.
• Suppleness is the range of motion a joint can move through (mobility) or the length a muscle can achieve (flexibility). The greater the range, the more speed and strength can be expressed in bowling, fielding (throwing, running) and striking movements. If this range is limited in any way it can cause injury. However there is a careful balance between mobility and strength as one without the other can lead to injury risk.
• Stamina or Work Capacity (to be more cricket specific about it) is the ability to maintain a level of work over time and to recover from work in intermittent bursts. So a bowler could bowl a longer spell or come back for more spells. A batsman could bat all the way through an innings and fielders could chase the ball around for longer. The more fatigued you are the more your technique suffers, the better your stamina the less you are effected by fatigue.

As you can see, all these elements are closely linked together. I would go so far as to say you cannot pick out specific components to train but need to develop a plan that works the whole body in the greatest range your fitness allows. As Gray Cook would say, you don't train fingers individually when you are learning to catch.