Fitness & Training calculators
Training intensity, strength benchmarks and the energy cost of activity.
3 calculators in this section
Heart Rate Zone Calculator
Five training zones from max or resting heart rate
One-Rep Max Calculator
Estimated 1RM plus a full percentage table
Calories Burned Calculator
Energy cost of activity from MET values
Intensity and volume
Heart rate zones set cardiovascular intensity, and the boundaries matter because different intensities drive different adaptations: low zones build aerobic base and mitochondrial density, high zones raise the ceiling on maximum oxygen uptake. Karvonen is the more accurate of the two methods here because it factors in resting heart rate, which is itself a fitness marker. One-rep max does the same job for the weights room, turning “three sets of eight” into an actual load on the bar without you having to test a true maximum and absorb the recovery cost. Calories burned measures volume through MET values, which is blunt as a training metric: two sessions can cost the same calories and produce entirely different adaptations.
Fitness & Training guides
Strength Training for Beginners: The First Twelve Weeks
Beginners adapt to almost anything, so the programme matters less than showing up. Here is what to do for twelve weeks, what to ignore, and why less is more at the start.
RPE and Reps in Reserve: Autoregulating Load Without a 1RM Test
Reps in reserve turns effort into a number you can programme against. How the scale works, how accurate it is, and why novices systematically misread it.
How to Start Running Without Getting Injured in Week Three
Your fitness improves faster than your tendons and bones can follow. That mismatch is why new runners break down, and why the fix is about patience, not form.
Rest Periods Between Sets: What the Research Changed
Short rest for size and long rest for strength was the standard advice. A 2016 trial and the reviews since it reversed the hypertrophy half of that claim.
Zone 2 Training: The Case For and Against the Internet's Favourite Intensity
Zone 2 is now the default prescription for aerobic fitness. The physiology is real, the evidence thinner than the enthusiasm, and the definition keeps moving.
How Many Sets and Reps? Reading the Dose-Response Evidence
Weekly sets per muscle group drive hypertrophy, and rep ranges matter less than most people think. Here is what the dose-response literature supports.