An arm sleeve that tells you if you're chucking

No more illegal bowling actions? (1:58)

A group of engineers from Pakistan have developed low cost technology that can determine the legality of bowling actions in an instant (1:58)

Of all the anachronisms that bedevil cricket, none has been as perplexing as the issue of chucking or, with more political correctness, bowling with illegal actions. For much of cricket's history, the rule on the village green was the same as that in international matches - the umpire used the naked eye to determine if an action was illegal.

The emergence of Muttiah Muralitharan, and the discovery early this century that nearly all bowlers had some amount of kink in their actions, belatedly brought science into the equation. The decision to use technology, to rely on biomechanical analysis recorded in labs, arrived from the desire to make things fairer, but it has also made things more confusing.

In a Cricket Monthly article on the question of determining the legality of bowling actions, Osman Samiuddin concluded by saying that the approach to it was "as if cricket's toes are partially dipped into the ocean of science and there is a great wave approaching".

We might not be seeing the wave just yet, but perhaps cricket is about to get more than its toes wet. A group of young Pakistani engineers claims to have developed a wearable technology that can measure the elbow flex in an action in real time, and so could potentially be used in match play. CricFlex, as the product is known, consists of small motion sensors (of the sort used in phones for orienting maps) attached to a sleeve that a bowler can wear. The device sends its readings to an app, either on a mobile phone or a computer, immediately after the bowler has delivered.

The team has published a research paper on the technology used, which was accepted at an MIT conference in 2015. They have also patented the technology in the US. But the device is still a prototype, and requires further testing. The patent affords it a degree of validity, and their work has been acknowledged by a leading biomechanist. They are now seeking formal validation testing from a biomechanics lab. They are likely to use the facilities at LUMS (Lahore University of Management Sciences), where the PCB has set up such a lab. Validation testing is ultimately what will provide the truest measure of how accurate such a product is - when its readings go up, for example, against the results of a marker-based system in a lab environment.

In January the CricFlex team tested the device with the Yuslim Cricket Club in Lahore. The prototype used by the CricFlex team comprised a generic sleeve made of the dri-fit material that is used in athletic apparel, and ran from mid-bicep to mid-forearm. A coin-sized sensor was attached near (but not on) the elbow joint, and the entire apparatus was largely unobtrusive; none of the bowlers tested complained of any interference in their movements as they bowled.

Each bowler was asked to wear a sleeve and then hold their arm in three positions - stretched out straight, bent at 45 degrees and then at 90 degrees. This allowed the device to orient itself to the particular bowler. The non-invasive nature of the set-up meant that the bowler could bowl normally, and the app showed the readings the second they delivered the ball.

But once we began, the stigmatising pressure of the process began to show. Several bowlers lost their lengths under trial, often delivering full tosses. Once they saw their readings, though, they would relax. However, a new concern soon cropped up, which highlighted how little bowlers at this grade understood the 15-degree rule. Some of them began to worry about readings like five degrees of flex, asking their coaches how they could bring it down to zero.

Indeed, that is the reality that grass-roots bowlers face - the fear of even a hint of kink in their actions. At this level, conditions such as hyperextension will not be picked up, and instead a bowler will more often be branded as having an illegal action than not. That will affect their prospects of progressing further up. Since the ICC crackdown two years ago, and right after it took its highest-profile victim, Saeed Ajmal, the PCB suspended a further 16 bowlers on the domestic circuit whose actions were reported to be illegal. At this level there are many stories among local cricketers of overzealous officials targeting one bowler or another.

Abdullah Ahmed, CricFlex's team leader, said Ajmal's ban was what spurred him and two others - Muhammad Jazib Khan and Muhammad Asawal - to develop the sleeve. It began life as a semester project at NUST (National University of Sciences and Technology), a top engineering university in Islamabad. The team - all software or electrical engineers - has now grown to five.

They told ESPNcricinfo that their main purpose was to make their technology accessible at the grassroots level. The estimated cost of one of their sleeves is around US$300, which is far more affordable and less cumbersome than sending a club player to a biomechanics lab for testing his action. CricFlex's ambitions, however, are not limited to just this level. "The ultimate goal," says Ahmed, "is to implement this [technology] within live matches."

Real-time testing, within a match, is cricket's final frontier. During its latest cleanse of illegal actions, the ICC worked with Griffith University in Brisbane to develop a sensor that bowlers could wear on the field, which would deliver instant readings. They trialled it on bowlers in nets at the Under-19 World Cup in the UAE in 2014. That experiment seemed to have overcome early problems with the calibration of the devices (once a bowler dives in the field, for instance, will the device need to be recalibrated?) but ultimately, burgeoning costs meant the project was not continued. Another university in Australia has developed a wearable inertial sensor system capable of measuring elbow extension during the bowling action; it has undergone validation testing and is currently in the process of being commercialised.

And this is where the potential of CricFlex's technology might really bear fruit, because apart from measuring the degree of flex, it also provides other fascinating data for coaches and analysts. As it stands, the device provides four readings on each delivery. Apart from the degree of elbow flex, it also measures arm speed, and what it calls arm twist and arm force. Arm twist is a measurement of the rotation in a spinner's forearm as they deliver; the latter is a measure of the effort a bowler puts in, in Newtons. These readings can provide valuable data on the levels of fatigue for the bowlers, their effectiveness for different variations, and insights on subtle changes in their actions across a spell or a match.

CricFlex's simplicity is appealing. The bowler wears the sleeve, which is then calibrated using a simple two-step process. When they bowl, the four data points show up instantaneously on the mobile, on a simple interface. All this means that some basic instructions would suffice in getting someone to start using the device.

The potential impact is significant. Since actions are generally not tested for all but the bowlers at the highest levels, many now look to take extreme caution with suspect actions. A technology like CricFlex, however, might allow club and academy officials to come to far more rational decisions quicker.

There is still some time before CricFlex can hope to come into common use, though. During the testing, the coaches sent in two young boys who both bowled offspin. They expressed their doubts about the action of one, but were very confident about the other. The boy whose action they suspected started off with a flurry of full tosses before eventually settling down. His action came in under five degrees of flex, and the coaches were surprised. They then looked forward to the other bowler, but were left aghast by his first reading - 35 degrees.

Abdullah and his team quickly diagnosed the problem. The bowler had a small trigger movement with his arms before bowling, similar to what R Ashwin has in his action. The device was reading the flex in the trigger movement rather than the action. CricFlex say that using one device across many bowlers would cause such issues, and they are using such tests to determine how to fine-tune their readings. They aim to eventually make highly customised sleeves, where the sensors are precisely calibrated according to an individual bowler's idiosyncrasies.

Like all exciting technologies, one of the things that struck me about this device was why it hadn't been invented earlier. The ingenuity of it lay in its simplicity, and its applications beyond measuring elbow extension are where its potential impact lies. Rather than worrying about bowling actions, analysts and coaches can now begin to fine-tune strategies and skills, learning how to best utilise the unique abilities of each bowler. In a few years, that wave of technological advancement could well be crashing all around the sport.