 There's a saying in cricket that batsmen can set up games or save them but it's the bowlers that win matches. A lot of skill and guile and a bit of luck is needed to take 20 wickets and win a test match. It can be a hard slog especially on flat pitches with an old ball against batsmen who are set and informed. Bowlers need a solid game plan and not only do they need to be good enough to execute they also need to adapt as the situation changes or when their plan is not working. We asked Jonathan Connor a specialist in skills acquisition with cricket Australia to help explain some of the techniques and strategies bowlers use and why they make certain decisions. Right at the start of the game the bowlers always looking to get into a bit of a rhythm to make sure that they're working efficiently and from a research perspective we don't know too much about what rhythm actually looks like but often it's a kinesthetic feel that bowlers talk about they feel like they're in rhythm they feel like everything's working towards what they're trying to do. One way for a ball to find their rhythm and gain confidence early is to bowl their stock ball. We often refer to a stock ball as a ball that bowlers are most confident in bowling it's almost their their natural and most practice action and it's something that whenever you perhaps feel a bit out of form or not quite bowling where you where you'd like to you always refer back to that you know stock delivery that you feel gives you the best opportunity to start to build up a bit more rhythm and a bit more pressure on the opposition. Bowling especially fast bowling is an unusual action and a complex one there are a lot of moving parts. Fast bowlers are not only trying to produce maximum velocity but also need to pitch it in a particular area while potentially trying to make the ball move. From a research perspective we often talk about during performance not to think too much about the movement itself but instead the movement effects so what it is that you're actually trying to do so pitch the ball on a good length that's where your focus should be externally on the environment as opposed to internally and on a specific movement given that the movement itself bowling is such a complex action there are so many moving parts if you focus internally on one you might find that a lot of others start to break down. For a bowler it's all about taking wickets and one of the most effective ways to do this is to create confusion for the batsman and make them hesitate. At the start of the game what the bowlers probably trying to look to do is get the batsman to play off the front foot and execute some vertical bat shots so often what the bowler might do is try and bowl what's called a good length delivery where the batter is in two minds or indecisive about coming forward or stepping back. Visually what it looks like for the batter given that every individual is different is a ball that's about the knee high to waist high. So for example with a full length delivery what we often see is batters execute a vertical bat shot off the front foot and it's quite stable it's quite comfortable and it's quite efficient. Likewise when a ball is pitched very short often we see batters step back to the ball and play a horizontal bat shot. Again that's quite a stable efficient position. However when bowlers bowl what's considered a good length delivery which can be anywhere between you know four to six meters from the batter it often becomes this region where it's not quite stable or not quite efficient to be on the front foot or the back foot. So the batter has a choice to make as to whether they go forward or back and this can often result in some executional errors and often result in a dismissal. As we have seen with batting being able to adapt is crucial in test cricket. Everything changes and changes quickly. A new ball is only new for so long the pitch starts to change and you might also have batsmen who are growing in confidence to complicate matters even further. And not only that like where you want to pitch is obviously incredibly difficult but also you've got a batter who ultimately can adapt and move to you. So if you're bowling a particular ball outside off you can have a batter like Steve Smith who will walk two stumps across and be able to play shots that you might not necessarily anticipate or expect a batter to play to you which can basically disrupt your game plan. What bowlers are often trying to look to do is is build up pressure for the batter. So whether they may score singles and boundaries often the bowlers looking for the batter to play high-risk shots or look uncomfortable. Both batters and bowlers will walk into a game with their own sort of game plan or their idea of what they're trying to accomplish or how they're going to try and accomplish it. But naturally you always have to adapt to not only the conditions but also the opposition. So while a good length delivery might be your stock ball that you feel helps you build pressure the ball in which you're looking to take a wicket with perhaps might change. So instead of being a little bit fuller and outside off it might be back of a length and short trying to get the batter to play a shot that he shouldn't play or that's incredibly high risk. So in that sense bowlers will often have a game plan and they'll often adjust it slightly depending on the conditions and the opposition. In a team there are many different types of bowlers. Captains will use different bowlers in spells throughout a game. The purpose and duration of each spell will be different based on the bowler, the batsman and the stage of the game. Similar to batting and rolls bowlers have their own sort of rolls. Bowlers might come in different spells, different periods of the game and have different game plans for that. So for example the game plan during the first six to eight overs of the game is going to be very different to what it might be during the 50th or 60th over when the ball and the conditions have changed. But ultimately the bowlers might employ a particular game plan for a particular spell. Bowling, that was a flip-up. Often you'd start to expect spin to come into play as the ball starts to deteriorate and get a little bit older. As the pace bowlers start to get a little bit more fatigued, spin bowlers provide the opportunity to deceive the batsman in different ways. Often they bowl quite a bit slower, however able to extract a large amount of lateral deviation off the pitch. So at international level off spinners often can impart over 2,000 revolutions per minute on the ball, while our league spinners often impart over 2,500 revs which gives them greater opportunity to spin the ball. One of the most interesting and perplexing developments in bowling has nothing to do with optimal spell duration or perverse swing. It's actually the success of left arm bowlers. The fact that we have seen so many left arm bowlers come through in the last sort of 10 to 30 years, we sort of draw on some previous research that's looked at the fighting hypothesis or the negative frequency effect where if you're an up and coming cricketer and you face 75% of your deliveries against a right handed bowler and only 25% against a left handed bowler, all of a sudden once you get to the higher levels that left handed bowler has an advantage, simply because you haven't seen them, you haven't attuned to their kinematic cues and perhaps you don't anticipate their bowling action as well as you do against right handers. So that's certainly been quite a big avenue of research that we're also looking at is the natural advantage that left arm battes and bowlers have.