How a vest is changing the way Team India trains
Lionel Messi wears it, so does Megan Rapinoe. Virat Kohli and Co put it on every time they practice, and every time they play a game. With the Tokyo Olympics less than a year away, the Indian hockey team is starting to reap its benefits too.
At first glance, it looks like a sports bra that has crossed the gender barrier—both men and women athletes wear it. What it is, is a compression vest with a small device—no larger than the palm of one’s hand and not heavier than a tennis ball—placed in a pouch on the back of the vests in between the shoulder blades. Its presence is hardly felt by those wearing it but its impact is resounding; there is hardly an elite sportsperson in a team sport in the world right now not being made to wear one.
Welcome to the world of the GPS tracker, a single technology that has united the vast and varied world of sports, and changed the way athletes prepare for their game.
When they were first introduced, the Global Positioning System or GPS tracker simply measured the distance traversed by an individual on the field. Not anymore. Now the device has an accelerometer and records just how fast and how many times an athlete is accelerating or decelerating. It has a gyroscope and a magnetometer, and they map the player’s body movement in 3D, track directional changes, and their positioning on the field. It has a heart rate monitor that feeds into complex algorithms to measure fatigue and training intensity.
All of those numbers get fed into a central database—an analyst can look at the metrics in real time, or compare weeks and months of training data to track progress, or watch for signs of an impending injury.
Virat Kohli—a self-avowed fitness freak—often attributes Team India’s recent success to improvements in the team’s fitness levels.
“Your brain is supporting what you do because of your body,” he said after the recent 3-0 Test rout of South Africa. “If you bowl three overs with full energy and you are tired for the next two, you will lose the opportunity to take a wicket after creating pressure. Look at Umesh (Yadav) field after a spell, you can’t tell that he is a fast bowler.”
The GPS vest has played a big part in that fitness transformation.
“After using the GPS device, we had a clearer picture on load monitoring. We now know the exact amount of high speed running, the metabolic load on every athlete in each session, the difference between real time and match time numbers,” said Shanker Basu, who introduced the Indian cricket team to the technology in 2018, halfway into his celebrated two-year term as the team’s strength and conditioning coach.
“These are vital information for a strength and conditioning coach to decide on the load and future course of action of the training,” he added. “Let’s say player X has played a match and run 2000m in the match where the speed zones are very high. That’s a red alert for me. I would recommend active recovery for him the next day. Apart from workload, we can also calculate the metabolic load, how much power the cricketer is generating. We get to know who is working hard and who is not.”
Before the cricket World Cup in June, the BCCI signed an agreement with a UK-based company, STATSports, that provides the technology and manages the data. STATSports, which also works with Barcelona, Liverpool, and the US women’s national football team— amongst hundreds of other teams—provides an avalanche of analytics: Time in Red Zone (total time spent above a certain percentage of maximum heart rate, basically, time spent at full physical intensity); a suit of numbers on running speeds, accelerations, decelerations; the G-forces being experienced by an athlete; a fatigue index; measures for metabolic rates; and even the load distribution between the left and right side of the body while running.
“There are 50 metrics that’s can be derived from the GPS device, I use only 10 for cricketers,” Basu, who now works for the IPL team Royal Challengers Bangalore, said. There’s such a thing, Basu says, as “paralysis with analysis.”
One of the first prototypes of the device was built in 2000 by Catapult Sports, a company that began as a joint project between the Australian Institute of Sports (AIS), the famed high performance sports training centre run by the Australian government, and the Cooperative Research Centres, another government program to develop technology.
The AIS’s objective for floating the program was to find a way of testing athletes on the field, instead of in controlled laboratory environments.
But the first devices were so large that they could not be worn by athletes—instead they were placed on rowing boats to measure their roll, pitch and yaw. By 2002, the device had shrunk enough to be taped on the body of the athlete, but it could do little more than measure the distances covered by an athlete. In the next three years, more and more sensors were fitted into a smaller and smaller device, and in 2006, the device was commercialised.
Now, Catapult Sports counts close to 3000 clubs and teams across 39 different sports as their clients, including India’s football and hockey teams.
Team India’s former Australian physiotherapist John Gloster, who now works with the IPL team Rajasthan Royals as their strength and conditioning coach, had an early taste of the tech.
“I remember Justin Cordy, who was with the Australian cricket team as the strength and conditioning coach and with me with the Bangladesh team back in 2003-04, used them,” Gloster said. “It was very basic. There was really the total distance covered.”
But even back then, the data had the power to startle coaches.
“When we saw the data for the first time on the actual distance that the cricketers were covering we actually thought that it was wrong!” Gloster said. “How can a cricketer, in a Test match or a four day match, be covering 20-25km in a day’s play when an ODI bowler covers only 12-15?
“What we don’t realise is that cricket is actually quite a physical sport and hence my push then (was) to really increase the physicality of cricket because we now knew that it is predominately an endurance based sport. On this base, we then have a series of ‘exertions’ or efforts of brief intense activity that needs to be trained for also. The numbers were telling us that and we needed to train appropriately.”
Once players began to wear it for matches, coaches had another rich vein of data to mine from; now they could do with great precision exactly what they’ve always wanted to do: mimic the match environment during training.
“Once you have got the data from the match, players’ efforts can be measured. How much time is spent by the player in certain speed bands, for example, speed bands of 10-15 km/h, 15-20 km/h, 20-25 km/h, 25-30 and then 30+ km/h. We measure what their top speeds are. We can measure how much time (in secs) as well as how much distance is covered within each of those speed bands. The match data effectively becomes the player’s baseline data, the physical benchmark we need to strive for in training environments,” Gloster explained.
“In the pre GPS era this was not possible. We could train an athlete to the best our capabilities but we could never know their exact body reaction on the field. But now we can dissect their performance down to the last second.”
You are being watched
The GPS vest now dictates every aspect of an athlete’s life across most team sports, but it was first wholeheartedly embraced by football clubs. Initially, players wore it only for training. By 2015, teams began to wear them under their jerseys during official matches. At the 2018 FIFA World Cup in Russia, teams were allowed to transmit the data real-time during matches and analysts could share the player information with the coaches. Like F1 cars, footballers now cannot take a step on the pitch without telemetry shadowing them.
Before the GPS era, a footballer’s physical performance was analysed by using a dedicated camera that followed a single player over the full duration of a match. An army of analysts then sat with the footage to break down when the player was walking, jogging, sprinting, standing still, jumping, moving sideways, etc. Imagine trying to capture a full team’s data in that fashion.
Now all of that analysis and much more—for example, in rugby, an important measure coaches rely on is the impact of a tackle on the players involved—begins to unfold the moment a player puts on the vest and steps on the field.
“The GPS devices have highly sensitive sensors. At any point of time all our devices are tracked by 17 satellites,” Pankaj Wankhede, the India representative of STATSports, said. “The frequency is very high. So, the positional accuracy is very, very high. So like in a 1000m area it can track up to 2cm.”
Teams are already using to make strategic decisions—in football, mapping a players accelerations, speed and heart rate in real time is helping managers make decisions on whether a player is tiring and needs to be substituted.
Then, looking at the data across several matches, a coach can identify with great accuracy the specific fitness parameters a player needs to work on.
Top football clubs and national federations are regularly in touch with one another about the GPS data of their players. This helps the teams in analyzing not just the physical capabilities of a player but also their mental state. A player’s decision making ability in a pressure situation is almost always directly proportional to how fatigued the player is. Studying the heart rate charts of players gives managers and coaches a precise understanding of how players are reacting to their workloads.
“This device helps in bridging the gap between the head coach and the strength and conditioning coach,” Gloster said. “We can present the exact numbers for communicating with the coaching staff about what we do, and why we do it. Also, for the players, it creates an internal environment for competition on fitness.”
India’s hockey team, gearing up for the Olympic qualifiers now, uses Catapult’s system. The team’s chief coach, Australia’s Graham Reid and its South African Strength and Conditioning coach Robin Arkell rely heavily on the data, and has seen it foster a sense of competition within the team when it comes to fitness.
“At the end of each training session, players come to the laptop to see if they have achieved their targets,” Arkell said. “During training, we can really work out where we are at. It is good for a player to realise ‘I am not working hard enough, look at others.’”
Each sport uses the data differently, creating algorithms that match the requirements of the game; in cricket, for example, a specific formula has been deviced to observe the workload of a fast bowler. By looking at the speed, acceleration, rotation and lateral flexion (at the time of delivery, mapped by the gyroscope which captures the body’s movement in three dimensions), the algorithm calculates the stress a bowler is under.
“It gives us a snapshot of the actual versus the perceived work rates,” Gloster said. “Extremely valuable for us to measure player loads and cumulative loads; we are better able to monitor injury risks. It also helps us a lot with a player who is returning to the sport after an injury. The match data for that injured player can be used as part of their ‘return to sport’ criteria.”
To eat or not to eat
This detailed knowledge of a players physical state also helps tailor individual nutritional requirements.
For example, the movement and speed details tells you whether the player is spending more time in aerobic or anerobic activities during a match. In the aerobic state, the body uses oxygen efficiently to fuel the activity, which is what happens in light to medium intensity activities, like jogging or walking. When the intensity goes up, like a hard sprint, the fast bowler during his or her delivery leap, the diving fielder, the body switches to anaerobic mode.
“Cricketers spend most of time in the aerobic oxidative state which means they are more effectively fuelled on things like fats,” said Gloster. “80 per cent of their effort in a match was spent in aerobic state, and the best fuel for aerobic exercise is actually the fat stores. There are some efforts that require some anaerobic fuels (glycogen stores) but not to the same amount. We have only been able to come to this conclusion based on the data received about work efforts of cricketers during a match situation.”
With the adoption of the GPS vest across sports, the next frontier could be the sharing of knowledge and training protocols between different disciplines. Within a sport, this transfer of knowledge is already common.
Before the 2018 FIFA World Cup, the coaching staff of most teams had access to GPS data on their players from the clubs they play in. This gave coaches the answers to critical questions: Which player was overworked and at risk of injury? Which player matched the physical requirements of a particular position?
A similar set of data, Gloster said, enables coaches in cricket to predict injuries. T20 cricket, for example, involves a higher number of high-speed sprints than Tests. Such sprints cause quick muscle fatigue, which in turn makes a player susceptible to injuries. By comparing data from training and from matches, coaches can see who needs to get better trained.
“A player, particularly a fast bowler, who is coming straight from a Test series to a T20 league, you know that they are in a very high injury risk zone because they are realistically 20% per cent down in preparation for the actual exertions of T20 cricket,” Gloster said.
“If we compare the GPS data of total distance covered and the time spent in certain speed bands by an EPL player and an Australian Rules (AFL) football player, the efforts are very similar to that of an international T20 player. So, my argument is that we need to adapt some of the training protocols of football and adapt them to T20 cricket.”