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Strokes of Genius

Tue, 12/18/2012 - 12:11pm
PD&D Staff

 

Twisthink overcame inherent water barriers to radio wave transmission by designing a Custom Communication Protocol for Avidasports.  The system’s AvidaMetrics devices accumulate performance data while the swimmer is underwater, then forward their cache each time the swimmer breaks out.Fourteen U.S. Olympians trained with it prior to this summer’s London games. College swim teams from coast to coast (Harvard, USC, Michigan, Northwestern University, and the U.S. Naval Academy, to name a few) have added it to their training arsenal. The first high school team to embrace the technology won its state championship, and numerous other high school programs now use it.

AvidaMetrics is the biggest little tool to hit the sports world since stopwatches. And it’s a training tool like no other. AvidaMetrics is a sophisticated telemetry system created by new-product development specialists at Twisthink in Holland, MI, for Avidasports. The system continuously captures nanoseconds of an athlete’s action on-the-fly, condenses and processes data for eight different performance metrics, and extracts two key stats that the athlete specified prior to the practice session, then feeds actionable info back to him or her through an earbud as they continue training nonstop.

All of it is accomplished in a time faster than it took to read that last sentence.

Meanwhile, data for the performance metrics is routinely refreshed on the coach’s tablet or laptop. He can talk directly to practicing athletes too, and every piece of data is sent to the Cloud, available for review on computer by the athlete or coach at any time. They can zero-in on individual training sessions, compare days, weeks or an entire season, as well as compare training performance with that of other team members.

Olympic-level training technology for new and developing athletes

It’s the kind of training assistance “elite” athletes often get from teammates and coaches

counting, clocking and recording stats with stopwatches, pads and pens, or reviewing competition videos after an event. AvidaMetrics, however, delivers far more info, more precisely and much sooner when feedback helps athletes the most. Perhaps even better, it enables developing sport enthusiasts to benefit from training assistance they couldn’t get before, nurturing their interest while helping them improve skills at an unprecedented pace.

Although Twisthink’s 11-year new-product development track record features a lengthy list of America’s largest global corporations, the design-engineering firm’s extensive expertise in radio frequency (RF) wireless technology offered precisely what startup enterprise Avidasports needed for AvidaMetrics technology. Creating custom communication protocols within stringent FCC guidelines is one of Twisthink’s fortes; they have introduced industries to an impressive array of advanced wireless systems.

Twisthink raised the technology bar again with AvidaMetrics. Not only is this a first for the sporting world, but among many sports for which this type of technology could be adapted, their first foray took on the most technologically challenging “wireless” sport application of all: Swimming.

Zeroing in on primary performance metrics

The product idea came from Avidasports President Bruce Burton while watching his daughter swim on her Detroit-area high school team. He noticed that she was a good sprinter, but had difficulty pacing herself to excel in longer distance races. He figured that some sort of speedometer to give swimmers a sense of progress during training sessions, not just after a workout, would be a big step forward.

Speed is just one metric captured on-the-fly by this system. Along with pace, it also monitors and records stroke count, average stroke tempo, average distance per stroke, length time and breakout time, all of which is tracked on a per-length basis. Additional metrics such as kick count and average kick tempo join the rest in the Cloud for later review and analysis.

Plenty of groundwork preceded actual system development, however. First steps for Twisthink were in-depth interviews with swimmers and coaches, reports Gordon Stannis, Director of Design, to identify product restraints and also to further clarify what the system needed to provide.

Director of Technology Paul Duckworth recalls that “One coach said ‘swimming is just a game of math.’ According to him, if you get the right number of strokes in the right amount of time, you’re Olympic caliber. Every stroke burns energy so if an athlete takes one stroke or two out of a length, it makes a huge difference.

“Coaches also asked about getting performance feedback as close to the swimmer’s actions as possible. This reflects a basic tenet of training: the closer to an event that feedback is received, the more meaningful and useful it will be.”

Key AvidaMetrics features address these issues. Before each training session, the swimmer can select two metrics (stroke count and length time, for example) for automatic audio feedback by the system, which hits his earbud split-seconds after completing each length, as he starts the next. That’s about as close as feedback can get. Also the coach, as noted earlier, can talk to the swimmer, and those messages can be replayed during review.

Identifying athletes, collecting the data, connecting the dots

AvidaMetrics can track activity by as many as 100 swimmers (500 devices) at any given time. Of course, the system has to correctly match data collection with each.

“Pairing individuals with devices is relatively simple with AvidaMetrics, compared to some systems we’ve designed,” says Duckworth. “While users switch devices daily or more often in other applications, here we have dedicated pairing: each swimmer is assigned a set of devices for the season. Once they’re registered, each time they put on devices, the code is identified and they’re immediately inserted into the system.”

More difficult was setting up automatic detection points for activity during training, and the signal processing expertise it required. “As soon as swimmers enter the pool, the system automatically detects when they’re swimming, then it automatically detects what stroke they’re doing,” Duckworth said. “It counts how many strokes, notes length times, all of the metrics for every single swimmer in the session.”

Automatic procedures for sorting and storing information and enabling comparisons — connecting the dots, so data could be managed sensibly — was accomplished with relative ease by Twisthink. Actually collecting and transmitting data during training, however, was another story.

War of the waves: water vs. radio

Interference with wireless communication can stem from many sources, including cell phones, general radio, “like” systems and other electronic devices. Twisthink is also no stranger to RF blocking — objects getting in the way. Especially with ‘wearable technology’ like AvidaMetrics, the body can be a primary perpetrator.

The activity of swimming itself, especially noise generated by arms moving in the water while wearing an AvidaMetrics device on each wrist, had to be addressed. “Activity is occurring and data is being generated nonstop; I can’t take five seconds to capture information that’s only there for a nanosecond of time,” Duckworth points out. “We had to employ special filtering techniques in order to extract information from these noisy accelerometer outlets in a timely manner.

Not only that, the phrase “wall of water” definitely applies when radio waves come into the picture. “With many frequencies on which you can build radios (transmit), water acts as an absorber; it’s an impeder,” Duckworth explains. “So if you’re underwater, which swimmers are most of the time, water will absorb so much energy per inch, you won’t have enough energy left to communicate.”

Further complicating things are FCC regulatory limitations. “The FCC restricts what you can do on various bands,” Duckworth adds. “There are only so many bands on which you can do what we wanted with AvidaMetrics. Those bands available for our purposes run into that ‘wall of water.’”

Adding even more difficulty to the barriers that had to be overcome are the number of performance data metrics being monitored at a nonstop rate, and the fact that the information is coming from as many as 500 devices at one time. While the athletes fit the description, this was definitely not a task for amateurs.

Genius: custom protocol breaks through with stroke-rhythm ‘breakout’ system

“There are multiple techniques that we can use to offset challenges posed by the environment,” Duckworth states. “In this case, we knew we had to deal with water penetration, that we wanted to run a certain data rate and needed to accommodate 500 devices all at the same time. So we triangulated on a radio band, a data rate and the rest to arrive at a really effective and reliable solution.”

As they have with many other clients, Twisthink created a custom radio communication protocol for AvidaMetrics. Considering the obstacles that needed to be overcome, some features aren’t what you’d expect.

“The frequency band we picked is probably the worst from a water absorbency perspective,” Duckworth reveals. It meets data demands and other criteria, however, and “the system we designed, sort of glides like a ghost through the ‘wall of water’; it takes advantage of the swimmer’s own rhythm and breakout time.”

How so? “You could call it a Store-and-Forward system,” he explains. “When a device is underwater and doesn’t have communication, it accumulates the information being collected. When the swimmer breaks out of the water, a radio link is instantly established and data is immediately communicated.

“Although swimmers break the radio link when they go underwater with each stroke, their activity also enables the system to reconnect at every breakout point. It required a custom protocol to make that happen; the one we created works really well.”

Overcoming device design challenges without impeding competitor performance

The aquatic environment also presented special challenges when designing the devices themselves. Noting that swimmers train against the clock and speed is of the essence, Twisthink’s Stannis says, “We knew that the sensors had to be rugged, yet they could not impair performance. Our experience designing wearable technology products for a wide variety of applications was a valuable asset here.

“The sensors we designed are small, lightweight and comfortable. We also took extra steps to make them waterproof at depths down to 20 feet.” Stannis points out that the length of charge was an issue, too. “Radios to communicate with the swimmers, whether from the coach or automatic system feedback, needed to work for hours underwater between charges.”

In the resulting AvidaMetrics product from Twisthink, technology and design entwine, creating a data-rich, athlete-friendly solution.

AvidaMetrics helps coaches do more coaching, athletes train themselves

In effect, Duckworth observes, “this product helps make the coach a better coach while making swimmers, to considerable degree, their own coach.

“Coaches simply don’t have the time to provide individualized feedback for every athlete. AvidaMetrics helps them track multiple aspects of multiple swimmers’ performance far more closely, as it’s happening. With ultra-precise details automatically delivered after each length, a coach can quickly pinpoint key metrics and supplement the data with suggestions radioed directly to the swimmer, on-the-fly.”

Automated length-by-length system feedback enables every swimmer to track performance and adjust tempo, stroke or other actions to improve results on their own. “Feedback like this can generate tremendous improvement in a very short period of time,” Duckworth asserts.

During post-practice computer review, athletes can mix-and-match and relate all eight performance metrics, assessing proficiencies and targeting areas for improvement. In joint sessions, coaches and athletes can collaborate while tracking progress, and set realistic short- as well as long-term training goals.

Helping athletes fine-tune their ‘clock in the head’

In the sports world, all types of athletes including swimmers, track and distance runners, even gymnasts and thoroughbred jockeys, rely on a theoretical clock in their heads to properly pace themselves. It instinctively provides a feeling of where they are time-wise at any given point, enabling them to optimize performance and results.

Recalling a coach who was constantly trying to get his swimmers to pay attention to how many strokes it took to get to a certain point in the pool or to complete a length, Duckworth says, “The AvidaMetrics system really drives that point home by doing the counting for them and helps athletes develop the clock in their head.”

From a business perspective, 20 more institutions recently signed letters of intent to add AvidaMetrics to their swimming programs. Bottom line, the training tool that Bruce Burton conceived and Twisthink developed, is helping this startup enterprise grow.

“Not surprising,” sums up Duckworth. “Whether they’re Olympic-level performers or early-development Olympic wannabes, AvidaMetrics offers athletes the kind of personal training assistance they need.

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