Persistent. Unyielding. Built for the disciplined.
Precision tools for endurance runners. Know your numbers. Own every mile.
Tenax Running exists for steady work, durable progress, and gear that earns its place. Field Notes are where we clarify the training principles behind that standard.
Clear training notes, useful resources, and gear notes for runners who value discipline over noise.
Seven practical tools for runners: training paces, race prediction, heart rate zones, VO₂ max, weekly mileage, lactate threshold, and run/walk planning.
Enter a recent race result
Enter a race result
Enter your heart rate data
Enter race or test data
Enter your current mileage
Enter race, pace, or HR data
Enter a goal and interval ratio
Good gear should disappear while you train. It should fit without distraction, hold up over time, move with purpose, and earn its place.
Tenax gear is being built slowly. No hype. No noise. Just the work.
Training principles, tools, and gear updates from Tenax Running. Built for runners who keep showing up with purpose.