Training load is easy to feel and hard to see. A week can feel fine while it quietly climbs, or feel heavy while the numbers stay calm. The Polarized Training Explainer was built to turn that feeling into numbers you can check. You do not need an account, and you do not need to install anything. Open the tool, enter a few details, and get a clear result in seconds. That simple step, done at home, makes the next weeks easier, because you always know what this week asks of you and what it does not.
This tool works in your browser. Enter your easy percent and hard percent. The explainer fills in the moderate middle and tells you whether your mix is truly polarized. It takes your easy and hard percents, fills the moderate middle as whatever is left of 100, and checks the polarized shape: at least 75 percent easy and at most 10 percent middle. The result appears below the form, in plain lines you can read at a glance. You can change any value and run it again, so the plan improves as your fitness or your schedule changes. Copy the result into your notes, or print it, and take it with you. The tool never asks for personal details, and nothing you type leaves your device, because all the maths runs on the page itself. This tool gives general training information only. It is not medical advice, and it does not diagnose or treat any condition.
Polarized training means living at the two poles and avoiding the middle. About eighty percent of the time stays easy, truly conversational, and about fifteen to twenty percent goes hard, truly hard, with only a few percent left in between. The idea sounds strange, because the middle feels like the sensible place, yet studies of elite endurance athletes keep finding this shape, season after season. The easy pole builds a huge aerobic base without much fatigue, and the hard pole delivers the sharp stimulus that raises the ceiling. The middle gives neither benefit fully, while still costing recovery, so polarized training simply spends less time there.
Why does load planning matter so much? Because fitness grows from steady stress plus rest, not from one heroic week. A plan that jumps too fast asks tendons, bones, and muscles to adapt faster than they can. A plan that never grows asks nothing, so nothing changes. The middle path is a small weekly increase, an easy day after a hard day, and a lighter week now and then. When you follow that shape, a hard session stays hard in a good way, and an easy session stays easy, which is exactly what lets you train again the next day.
How to use it, step by step. First, be honest about where you start: your current level, your free days, or your starting numbers, as the tool asks. Second, enter those values in the form, using the units shown beside each box. Third, press the button and read the result from top to bottom. Fourth, change one thing at a time if the result looks too hard or too easy, and run it again. A good plan usually needs two or three short tries, and that is normal. The goal is not a perfect plan. The goal is a plan you will actually follow for weeks.
Start with the example already in the form. It shows a sensible starting point, with realistic numbers and a shape you can trust. Run it once, just to see the form of the result. Then replace the example with your own numbers, and run it again. Compare the two results. If your own plan is much harder than the example, that is a warning sign, not a challenge. Scale one number back, and the whole plan will feel calmer at once. Small plans finished beat big plans abandoned, every single time.
Polarized is a weekly pattern, not a single session rule. One moderate session in a week does not break it, but a week where every session sits in the middle does. Keep notes on how each week felt, in one line per week. Felt strong, felt tired, slept badly, or felt easy are enough. After four weeks, those notes show your real pattern better than any single number. If two weeks in a row felt hard, hold the plan steady for one more week instead of pushing on. If two weeks felt easy, raise one number slightly. Your notes turn a generic plan into your plan, and that is when progress gets steady.
Can I use this tool for free? Yes, it is free, with no account and no sign-up. Does it work on a phone? Yes, it works in any modern browser, on a phone or a computer. Can I change the plan later? Yes, change any value and run it again as often as you like. What if a week feels too hard? Repeat that week, cut one session, or lower one number, then carry on. The tool shows the maths clearly, so you can see exactly how each week is built. Remember, this is general education only, not personal medical or coaching advice.
Spanish version: Explicador de Entrenamiento Polarizado