Turn available time and a clear goal into a reviewable training week, with easy days, purposeful work, complete session durations and feedback from the log.
Change a session and compare the time spent in each domain with the purpose of each workout. Warmups, recoveries, and cooldowns count toward total minutes.
Illustrative three-domain model. The boundaries represent a first and second physiological threshold; these domains do not map one-to-one to a device's five zones. The preset splits are teaching examples, with whole minutes rounded and total duration preserved.
Easy sessions contain 100% easy time. Tempo sessions put half the time between thresholds. Interval sessions put one third above the second threshold. Remaining minutes are easy. These splits do not prescribe a workout or an ideal weekly ratio.
260Total minutes
5Total sessions
Each minute contributes to one domain. The denominator is all 260 minutes, including the easy portions of tempo and interval sessions.
Time distribution across illustrative intensity domains
Domain
Minutes
Share
Below first thresholdLower-intensity domain
220
84.6%
Between thresholdsMiddle-intensity domain
23
8.8%
Above second thresholdHigher-intensity domain
17
6.5%
Different denominators answer different questions.
An interval workout can contain mostly easy minutes and still count as a higher-intensity session. Neither view establishes a universal “80/20” target. Your sport, training history, recovery, and goals shape an appropriate plan.
Start with a goal and the routine you already have
A useful plan names what you want to practice or improve and begins with your recent routine. A first repeatable exercise week, preparation for an event and maintaining a familiar habit are different goals. Available time is a constraint to plan within, not a target that must always be filled.
List recent sessions, their complete duration, the longest outing and other demanding activity. Include strength work, races, long walks and rest so the endurance-zone summary is not mistaken for the entire physical load. The log should make the starting point visible before you add complexity.
Consider time and intensity together
A weekly percentage can conceal the actual dose. The same easy share at three hours and twelve hours represents very different amounts of easy and harder work. Likewise, adding time while preserving the percentages still changes the total program.
Studies of mitochondrial adaptation consider intensity alongside the frequency and duration of training. Per-hour efficiency and complete-program improvements answer different questions. Keep total minutes next to the distribution, and use research relevant to your outcome rather than choosing a ratio because it looks scientific.
Name an easy outing as easy, a steady-work session as deliberate steady work, and an interval session by its work-and-recovery structure. That makes it possible to compare intention with execution later. A session color on its own cannot distinguish purposeful tempo from an easy day that drifted upward.
Leave room around demanding sessions for the rest of the routine. This guide does not assign a mandatory number of hard sessions, a universal recovery interval or a required 80/20 split. If the plan is harder to repeat than expected, simplify the structure before chasing an ideal-looking chart.
State the aim of the session in one sentence.
Include preparation, recoveries and the finish in its time budget.
Record the intended metric and zone method.
Keep lighter days and rest visible in the week.
Progress through a block with changes you can interpret
Changing every part of the plan at once makes the response difficult to interpret. Keep a record of which part changed: session count, duration, work structure or intensity. A familiar easy outing can provide continuity while a purposeful workout changes.
Distribution can also evolve across a block. A randomized runner study compared maintaining pyramidal or polarized training with switching between them. Its trained male population limits direct application, but it illustrates why the phase and sequence belong in the research question.
At the end of the week, compare planned and completed time, the purposes of sessions and how the routine felt. Look for repeated patterns before interpreting an isolated day. An unusually hard easy outing may have a different meaning if the weather, route or sensor also changed.
Use the distribution as one view beside these notes. A target ratio cannot certify recovery, prevent injury or tell you which session should come next. If a calculator labels the pattern, read its assumptions and confirm that its grouped bands match the definitions you actually used.
Use a planning tool to organize a choice you can review
The weekly volume calculator divides time and an easy share you choose. The interval planner fits a possible complete session within its model's time and intensity budget. These are ways to explore a plan, not assessments of your body's required training volume or readiness.
Preserve their outputs as proposals, then compare them with actual sessions and your goal. An easy-only plan, a shorter session or a rest day can be a useful choice. For individualized programming or a personal assessment, bring the log and its context to an appropriate professional.
Sources and further reading
The examples in this guide illustrate training concepts. Percentage bands and planning heuristics are identified as conventions; they do not measure your individual thresholds. The research library describes study populations, methods, outcomes, and limitations.
Mølmen, Almquist and Skattebo · 2025 · Systematic review and meta-regression; published online in 2024 and in the 2025 journal volume, with searches through February 2022.
Practical interpretation: Compare intensity, duration and the outcome together. Gains per hour and gains over a complete program answer different questions.
Limits: Broad training categories, different measurement methods and statistical adjustments. Meta-regression associations are not randomized comparisons of every possible program.
Filipas, Bonato, Gallo and Codella · 2022 · Four-group randomized trial over 16 weeks, comparing fixed distributions and changes between them.
Practical interpretation: The distribution can change across a season. Treat periodization as part of the comparison rather than asking only which single pattern wins.
Limits: Most significant changes were below the smallest detectable change; the relative VO2peak trend was largely attributed to weight variation. The trained male sample limits transfer to other runners.
Gillinov and colleagues · 2017 · Device-validation experiment comparing contemporaneous wearable readings with ECG.
Practical interpretation: Check signal quality before interpreting a sudden zone change. Compare sensors when an unexpected reading drives a training decision.
Limits: Specific 2017 devices and laboratory conditions. These results cannot rank today's hardware or guarantee that every chest-strap reading is correct.
