Sensors drive better safety and performance

Innovative materials and devices improve safety and support athletes’ health. By providing personalized data, they also drive improvements in technique, posture, and more. This unprecedented insight into athlete health, recovery, and performance has made wearable devices game changers in sports.

These advances go beyond high-performance fabrics that provide benefits such as compression or UV protection. Today, wearables range from wrist monitors to GPS sensors to smart clothing, equipping athletes and coaches with real-time data on physiological and performance metrics (see Figure 1).

Here are some of the cutting-edge breakthroughs enhancing athletes’ work on and off the field:

Wearables and sensors protect athletes’ health

Advanced textiles now feature embedded sensors that monitor bodily processes such as heart rate, respiration, and muscle activity. Heart rate monitors, for example, measure an athlete’s heart rate in real-time, typically using optical sensors that detect blood flow through the skin (photoplethysmography or PPG) or via electrocardiogram (ECG) sensors that record the heart’s electrical activity.

Athletes use heart rate data to stay within specific heart rate zones during training, ensuring they are working at the desired intensity for aerobic or anaerobic conditioning. By tracking heart rate variability (HRV), athletes can assess their stress levels and overall well-being, which is crucial for avoiding burnout. A higher HRV indicates good recovery, while a lower HRV may suggest the need for rest. Heart rate data during competitions also helps athletes understand how their cardiovascular system responds under stress, which can inform future training adjustments.

Respiratory rate monitors, usually in sensors integrated into chest straps or smart clothing, detect the expansion and contraction of the chest or changes in air volume. Athletes can use respiratory data to improve their breathing techniques, such as diaphragmatic breathing, and enhance their oxygen uptake.

Oxygen saturation (SpO2) sensors also provide insights into an athlete’s oxygen levels by measuring the percentage of oxygen-saturated hemoglobin in the blood. These sensors typically use light to measure oxygen levels through the skin (pulse oximetry). Monitoring SpO2 levels during and after exercise helps athletes understand their body's ability to deliver oxygen to muscles, a crucial metric for recovery and endurance.

Hydration and electrolyte monitoring are important as well, and wearable devices can now analyze sweat composition to provide personalized hydration recommendations. These devices can track electrolyte concentrations in sweat to provide feedback on electrolyte balance, which is important for maintaining optimal muscle function and preventing cramps.

Wearables also measure sweat rate to provide insights into fluid loss during exercise. Often using microfluidic channels to guide the sweat into the sensor, these devices detect and analyze sodium, potassium, chloride, and other electrolytes as well as hydration markers like lactate and glucose.

Another type of sensor for hydration monitoring uses electrical impedance, sending a small, harmless electrical current through the body. The resistance (impedance) to this current varies depending on the body's water content and electrolyte levels. Since water and electrolytes conduct electricity, the impedance values can be used to estimate body fluid levels. Some devices use colorimetric sensors that react with sweat to indicate hydration and electrolyte levels. The intensity of the color change is measured by an optical sensor, which translates this into quantifiable data.

Driving better performance plus lowering injury risks

Real-time data on the body’s movements and physiological processes guides decisions about safety and training intensity. It also informs athletes about their movements and techniques so they and their coaches can personalize training activities for peak performance.

For example, electromyography (EMG) sensors, which can be integrated into smart clothing or attached to the skin, measure muscle activity by detecting electrical signals generated during muscle contractions. By analyzing muscle fatigue and imbalances, EMG sensors help athletes avoid overuse injuries and optimize muscle recovery. EMG data also lets athletes monitor which muscles are being activated in specific exercises to ensure proper technique.

Pressure sensors embedded in footwear or clothing have a similar effect. These sensors measure the force exerted by different parts of the body during movement. Runners and other athletes use pressure sensors to analyze their gait and foot strike patterns, which helps prevent injuries like plantar fasciitis or shin splints. Athletes in sports such as weightlifting use pressure data to ensure proper weight distribution and technique during lifts. This provides insights on excessive strain or overuse, helping athletes refine their precision movements.

Similarly, motion tracking sensors such as inertial measurement units (IMUs), a combination of accelerometers, gyroscopes, and magnetometers in a single unit, can detect nuances in technique, helping athletes make adjustments that improve efficiency and reduce the risk of injury. In sports like tennis, golf, or baseball, motion tracking sensors can analyze an athlete’s swing, providing feedback on speed, angle, and motion fluidity. For sports that involve jumping, such as basketball or volleyball, motion tracking can measure the height and force of jumps, helping athletes optimize their explosive power while protecting themselves from injuries.

The components of these IMUs are valuable for other types of precision data, such as changes in speed or direction. These measurements help runners and walkers monitor their steps taken, cadence, and movement patterns. Gyroscopes, which measure rotational movement and orientation, are useful for tracking complex movements like flips, turns, and twists, especially in sports like gymnastics, skiing, or skateboarding.

Even GPS sensors have a role in sports technology — they allow athletes to map their routes in real time or review their route, pace, and elevation post-workout. Marathon runners can use these sensors in apps to refine their strategy for future runs.

The future of athletic training

Sensors and wearable technology will continue to evolve, and future developments may include more sophisticated sensors, greater interoperability between devices and platforms, and AI integration for predictive analytics. As bioelectronics advance, smart materials and devices may one day assist athletes with training and perfecting their technique.

By providing real-time, personalized data, sensors and wearables empower athletes to push their limits while staying healthy and injury-free.

‍

For more information, see the ACS Applied Nano Materials article, "Nanoscale Materials in Biomedical Applications of Sensors: Insights from a Comprehensive Landscape Analysis."