Photo via Athletics Weekly

Fourth Frontier X3 review: going beyond your sports watch

The Fourth Frontier X3 is a 23g chest-worn wearable that utilizes ECG technology to provide more precise heart rate data than standard optical wrist sensors. By tracking metrics like heart rate variability, training load, and cardiovascular strain, the device offers endurance athletes deeper insights into their physiological response to exercise.

The unit features a screen-free design, USB-C charging, and a battery that lasts up to four months with daily use. Athletics Weekly readers are currently eligible for a 30 percent discount on the product.

Up nextAthletics· 2d ago

Why pacing a marathon is just risk management in trainers