Modern wearable sensors utilize global positioning system (GPS) technology to track basic movement data that has both statistical and medical implications in the sports world. This article highlights the ingenuity of such sensors, which weigh only one ounce yet contain an accelerometer (measures starts and stops), gyroscope (measures bending and twisting of the body), magnetometer (measures direction), and a microprocessor that collects and parses more than 1,000 data points per second in real time. The potential impact of these sensors on the NBA, as well as some of the sensors’ shortcomings such as player concerns, is also addressed. However, the main purpose of this article is to emphasize the importance of such data in reducing the risk of injury to professional athletes and preserving the longevity of their careers.
The Move Towards Science in the NBA
Recently, the National Basketball Association (NBA) decided to invest in a Mayo Clinic study on the effectiveness of wearable sensors developed by Catapult and STATSports, two leaders in the wearable tech industry (See Fig. 1) . While many studies exist regarding the effectiveness of wearable sports technology, having its own study would allow the NBA to dictate the potential topics . Many of the minor, development league teams and even a few NBA teams are using wearable sensors during practice, but the NBA has yet to showcase them during a regular season game. The sensors utilize global positioning system (GPS) technology to track basic movement data such as speed and distance traveled, but also more advanced vector quantities including force, acceleration, and deceleration, which are all critical in basketball-related actions such as being first to the ball, beating an opponent to a zone, and blocking scoring opportunities . According to an article by Zach Lowe from ESPN’s Grantland, the sensors can not only track how fast players move, but also how well players move . Along with statistical information, the sensors could help coaches and trainers acquire valuable health and fatigue-related information.
Playing professional sports at the elite level can be extremely tough on the human body. The muscle action associated with accelerating and decelerating is especially demanding both energetically and physically and rapid changes in acceleration (i.e. cutting, sudden stops, and stand to sprint motion) can lead to muscle damage that inhibits an athlete’s play . Access to acceleration data would not only allow team experts to quantitatively measure how fast a player moves, but also look for deviations from a player’s average speed—a possible indication of fatigue. Keke Lyles, director of athletic performance for the Golden State Warriors, uses Catapult’s sensors to gauge player’s fatigue, which is the source of many non-contact injuries . Lyles said about the sensors, “If we see big drops consistently over the last few games, and we know in practice they've dropped and they're telling us they're tired and sore and beat up, then we start painting a big picture: ‘Yeah, these guys are probably fatigued.' When they're fatigued, they're at a higher risk” . The sensors are also able to measure the impact of force when players jump or land. Force data allows experts to determine whether a player is favoring one leg over the other, a possible indication of a masked injury .
Catapult Sports/Toronto Stars
Advanced technology is gaining a larger and larger role in professional sports. In 2013, the NBA outfitted every team’s arena with a SportVu camera system that tracks the position of every player and the ball in almost real-time. Teams can also use this service to obtain player-specific data and have experts analyze that data. While the cameras have provided very useful data for assessing player skill and ball movement, the engineering of Catapult’s sensors and others like them takes basketball data to an entirely new level. Catapult’s sensors, based out of Melbourne, Australia, are about the size of a car-clicker and fit into the lining of a compression shirt. Within this one-ounce sensor are an accelerometer (measures starts and stops), gyroscope (measures bending and twisting of the body), magnetometer (measures direction), and a microprocessor that collects and parses more than 1,000 data points per second in real-time . Similarly, MC10, a tech start-up based in Cambridge, Massachusetts, has developed a sensor prototype called Biostamp that is an even greater feat (See Fig. 2). Biostamp is a “barely visible 2-square-inch patch” similar to a Band-Aid that can “stick on any body part like a second skin and record biometric data from heart rate and hydration levels to muscle activity and sleep patterns” . These are just a few of the many tech companies starting to delve into the professional sports market.
Compass H20/Compass H20
Other applications from USC to Australia
Furthermore, the NBA is not the only organization that realizes the importance of such information. Catapult works with professional sports teams all over the world from Australian rowing crews to Irish rugby teams and the Indianapolis Colts. As a result of this boom in demand for sports information, researchers are also recognizing the need to provide such data. Kristamarie Pratt, a PhD Candidate in Biokinesiology at the University of Southern California, is working with USC’s Human Performance Lab to develop a novel method for quantifying knee loading asymmetries, or differences in the weight that a patient puts on their injured knee versus their uninjured knee (See Fig. 3). At the Human Performance Lab, Pratt and other USC researchers use an advanced 3D motion capture system coupled with force plates and body markers to measure knee-loading asymmetries.
Though Pratt’s research focuses primarily on these asymmetries in patients who need post-anterior cruciate ligament, or ACL, repair, she says, a “similar type of paradigm can be applied to many different lower extremity movement impairments and help change the physical therapy world” . Pratt’s research is also focused on preventing re-injury in athletes, something many NBA players, like Derrick Rose most recently, know about all too well. Using sensor technology will give clinicians information that can’t be seen with the naked eye and since the sensors can ideally be taken home with the patient, help guide at-home physical therapy exercises as well (See Fig. 4) . According to Pratt, “If individuals are able to practice their exercises properly then they will not develop altered movement patterns that put them at risk for re-injury” . The obvious advantages of reducing injury rates are not up for debate, but the actual implementation of the technology might face some opposition.
Future Directions for Sports Science
There are a few logistical limitations to the Catapult sensors that will need to be resolved before the NBA and others can fully depend on their data. Since the sensors rely on GPS technology, it is difficult to obtain a strong signal in indoor facilities and a nightmare to do so during games with a packed arena . Also, because of their dependence on GPS, the sensors can only track movement in a plane and not other movement such as jumping and reaching. One reason the NBA is yet to use sensor technology during games is because of the effect it could have on a player’s ability to perform well. The sensors can be bothersome or distracting for players, whose focus should be on winning the game . Furthermore, the sensors and their corresponding equipment are expensive to institute on a wide scale . According to Catapult, the cost of sensors can range anywhere from $500 to $2,000 depending on the sport and not including the cost of any additional technology needed to collect and interpret the data . While cost might not be an issue for the NBA, it limits the benefit of these sensors to only high-level professional sports and precludes the impact these sensors could have on the amateur and collegiate levels. Injuries even tend to be higher at the lower levels because of the lack of professional training among coaches and athletic trainers . All of these issues must be resolved if wearable technology companies and researchers want to make a lasting impact on the sports world.
Pratt, however, is hoping to tackle both the GPS and cost issues by taking the information gathered from high tech set-ups and translating it into wearable inertial sensors usable in any clinic or on any field. Inertial sensors are not only more cost-effective, but they can also be used anywhere with a computer. “Using inertial sensors,” Pratt said, “we can identify in a person subtle changes in movement and if a person is not using their knee properly” . This is valuable information that the NBA is hoping to garner through Catapult’s wearable sensors. While Pratt thinks the sensors “are a great idea to give an overall impression,” she cautions the NBA and team staffs “not to rely completely on their output as these are gross measures of movement and the human body is an intricate machine” . There is also some hesitancy among NBA players to adopt the sensors during games, despite their potential health benefits.
Arbogast, Rex./Post and Courier
The NBA players’ union has voiced some concerns about how this health data will be used. Some players are worried that a negative health report—for example, one that indicates a potential but not yet evident injury—could affect a player’s leverage during contract negotiations . Also, since the NBA, not individual teams, would own the sensors, players are worried about who would have access to their health data. The sensors raise some serious questions for players, coaches, and general managers alike. What if the media finds out the training staff let a player play through a serious injury? What if a player’s data has him on “red alert,” but it’s Game 7 of the NBA Finals? . These concerns beg another question that engineers in information technology are frequently faced with: how much information is too much information, and at what cost?
Despite these concerns, there is undoubtedly a strong need for this type of research as the high rate of injuries continues in the NBA . Serious sports injuries and the looming risk of re-injury can negatively affect a player’s ability to return to the same high level of play after injury. Pratt says she chose this research because she finds this fact “heartbreaking” and hopes her research “can prevent those bad movement patterns and prevent re-injuries to athletes who are so invested in their games” . The NBA has always been a champion of implementing new technologies and has only become hungrier for new tech with the arrival of younger, tech-savvier Commissioner Adam Silver. The NBA has the ability to completely transform “how teams scrutinize, optimize and fundamentally think about their players,” but only with the help of today’s most innovative engineers .
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