Design Wearable Sports Technologies that Change the Game

Author:
Sudhir Mulpuru, Business Management Director, Industrial & Healthcare Business Unit, Maxim Integrated

Date
09/30/2019

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Fitness buffs can now take advantage of plenty of options for continuous monitoring as they strive to achieve personal bests

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Figure 1: Runners are among the many athletes and fitness buffs who can monitor their performance via wearables

When Liverpool hoisted the European Cup after winning the Champions League final against Tottenham Hotspur in June, the moment also was a highlight for wearable sports technology. Both football clubs use StatSport’s GPS-based athlete performance-tracking system, which provides real-time metrics on parameters such as maximum speed, total distance, and sprints via a pod and vest solution. Armed with this knowledge, the clubs could adjust their training and preparation methods accordingly.

This performance-tracking system is probably more sophisticated than what the casual sports enthusiast would need, but even fitness buffs have plenty of options. From recreational sports participants to weekend runners to professional athletes, more people are taking advantage of wearable technologies to assess their progress and performance and their overall well-being.

In the sports technology market, which is projected to reach USD 31.1 billion by 2024, wearables represent the largest and fastest growing segment, according to research from analyst firm MarketsandMarkets. It’s no wonder—wearables equipped with biosensors come in convenient and comfortable formats, such as wristbands, clothing, chest straps, belts, and jewelry. These devices continuously collect data and, when this data is analyzed with sophisticated algorithms, it yields valuable insights about athletic performance and overall well-being. In this article, we’ll take a closer look at how wearables are changing the sports and fitness landscape and what kinds of underlying technologies are needed to create effective wearable devices.

Fine-Tune Your Fitness Routine

Wearable technologies provide an array of benefits to athletes and anyone interested in fitness and well-being. Wearables can track key parameters such as heart rate, blood-oxygen level, stress levels, body temperature, and sleep quality. These insights can contribute to more productive workouts, better chronic disease management, more proactive preventive care, and also a more personalized healthcare model. For athletes in particular, the devices as well as software tools can help with player safety assessment, workout injury prevention, and physical conditioning and performance. GPS sports watches worn during practice sessions can help improve golfers’ swing mechanics, for example. RF technology-based tracking systems can track acceleration, jumps, and other movements by basketball players. Smart sports apparel worn by race car drivers can monitor heart rate as well as metrics like the speed of the car and distance covered. In fact, the benefits of wearables extend beyond the athletes to the spectators. For instance, smart wristbands worn by fans serve as electronic tickets, deliver game updates, and provide a payment mechanism at concession stands.

For wearable sports technology to be effective, it must be highly accurate, provide measurements that are useful, operate for long periods of time between charges, and be comfortable and unobtrusive. Let’s examine the key technology requirements for these devices.

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Figure 2: Chest straps are one of many form factors for wearable heart-rate monitoring technology that athletes and fitness enthusiasts can use

Biosensors Uncover a Wealth of Wellness Data

Continuous heart-rate monitoring provides the beat-to-beat-to-beat data that is an indication of heart-rate variability, which tells a lot about the body:

· How well it is reacting to exercise

· How well it is recovering from the activity

· Fitness levels and any related improvements

· How well it is tracking to goals

· Remaining energy during an activity

Providing this type of data requires optical and mechanical design expertise, low-power electrical design know-how, and algorithm capabilities. As for the components, they should ideally be precise, small, and consume very little power.

Advancements in optical sensors have been a significant contributor to the efficacy of wearable health and fitness monitoring solutions. Sensors can now accurately monitor photoplethysmography (PPG), body temperature, and other vitals. There are now even biosensor modules for wearables that integrate multiple parameters, such as synchronized PPG with electrocardiogram (ECG) monitoring. Using light to interrogate tissue, PPG provides an optical measurement of the volumetric change of blood in tissue during the cardiac cycle. ECG, on the other hand, uses electrodes to measure electrical signals in the heart. Both can be used to provide heart-rate measurements, and ECG sensors also yield reliable heart-rate variability data. PPG monitoring is particularly challenging, however, as it is affected by ambient light, different skin conditions and colors, blood perfusion, and physical motion artifacts.

The challenges of integrating optical-sensing technology into wearables will vary based on the end device. Getting accurate measurements from smartwatches will be tougher than doing so in in-ear monitors, for instance. The wrist is an area with low blood perfusion and high motion, which creates noise that impacts the readings. The ear has higher blood perfusion and, therefore, can yield more precise measurements.

Development Platforms Streamline the Design Cycle

To answer the call of wearable sports technology designers, IC vendors have continued to make advancements in semiconductor solutions that address accuracy, power efficiency, and size challenges. Maxim, for example, has long been focused on developing products that provide the insights to enable a healthier world. Two of its newest platforms are targeted toward wearable health and fitness applications. MAX-HEALTH-BAND is an evaluation and development platform that streams raw data from sensors or processes raw data to output heart rate, heart-rate variability, activity classification, calorie consumption, and step count information. The platform, which can shave off up to six months of development time, includes:

· The MAX86140 ultra-low-power optical pulse-oximeter/heart-rate sensor (Figure 3), which has a low-noise signal conditioning analog front-end (AFE), including a 19-bit analog-to-digital converter (ADC), an ambient light cancellation circuit, and a picket-fence detect-and-replace algorithm. The picket-fence algorithm enables consistently accurate heart-rate detection under varying light conditions, such as shadows and bright light.

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Figure 3: MAX86140 block diagram

· The MAX20303 wearable power-management IC (PMIC) (Figure 4), which includes an eccentric rotating mass (ERM)/linear resonant actuator (LRA) haptic driver with automatic resonance tracking, micro quiescent current boost and buck regulators, a linear lithium-ion battery charger, micro quiescent current low-dropout (LDO) regulators, and an optional fuel gauge.

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Figure 4: MAX20303 block diagram

· Maxim’s motion-compensated algorithms, which extract data based on PPG signals

The other new platform is MAX-ECG-MONITOR, an evaluation and development platform for monitoring clinical-grade ECG and heart rate. It’s available in a wet electrode patch for clinical applications, as well as a chest strap for fitness applications. The platform includes the MAX30003 ultra-low-power, clinical-grade, integrated biopotential AFE, which provides ECG waveforms and heart-rate detection. Its continuous measurements can be useful for trend- or predictive-type applications. Because the platform’s built-in heart-rate detection includes an interrupt feature that eliminates the need to run a heart-rate algorithm on a microcontroller, it yields robust R-R detection in a high-motion environment at very low power. The platform supports long battery life through a couple of key features: operation at 85µW at 1.1V supply voltage and configurable interrupts that allow the microcontroller to wake only on every heart beat to reduce overall system power.

Summary

From weekend joggers to professional athletes, more people are taking advantage of wearable sports technologies to monitor fitness levels, track progress towards goals, enhance performance, guard against injuries, and much more. Delivering accurate data from wearable form factors requires underlying technologies that are precise, power efficient, and small. IC vendors are up for the challenge, delivering resources for designers to create smartwatches, chest straps, clothing, and other wearable devices that deliver continuous, real-time health and fitness insights to shape their performance.

Maxim Integrated

www.maximintegrated.com

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