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How masters swimmers can structure a 12-week progression block

8 min read

Written by DuoSwim Team 14 Feb 2026

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Masters swimmer completing structured pool training

Quick answer

A practical 12-week masters swim block uses four phases: technique and aerobic consistency in weeks 1 to 4, threshold development in weeks 5 to 8, race-specific work in weeks 9 to 11, then reduced volume and a benchmark in week 12.

Set a baseline before week one

Choose one benchmark that reflects your goal and can be repeated in week 12. A 400m time trial works for general aerobic pace; 8 x 100m on a fixed send-off gives more information about repeatability; race-specific swimmers can use a broken version of their target event.

Record pool length, total time, individual splits, rest, equipment, and perceived effort. The comparison is only useful if the final test uses the same conditions.

Weeks 1 to 4: technique and aerobic consistency

Use the first month to establish repeatable attendance and clean mechanics at moderate effort. Across three swims, combine one technique-led aerobic session, one steady endurance session, and one short pace introduction. A fourth swim, if used, should be easy enough that it does not compromise the other three.

  • Keep drill choices tied to one observable issue, such as head position or catch timing
  • Increase weekly distance gradually only while stroke quality remains stable
  • Use relaxed aerobic repeats long enough to establish rhythm but short enough to reset technique

Weeks 5 to 8: build threshold repeatability

Introduce one threshold-focused main set each week, such as 8 x 100m or 5 x 200m at a pace that is demanding but repeatable. Keep the send-off consistent and aim to narrow the spread between fastest and slowest repetitions before trying to make the whole set faster.

Maintain one easier technique session and one aerobic session. If recovery worsens or pace deteriorates across two weeks, reduce the main-set volume before removing the technical work.

Weeks 9 to 12: race specificity, reduction, and test

In weeks 9 to 11, replace part of the general threshold work with the pace, stroke, turns, and repeat length that match your target event. Keep quality high and rests deliberate; race-specific does not mean every repetition is maximal.

In week 12, reduce total volume while retaining a small amount of pace work, then repeat the baseline benchmark when reasonably fresh. Compare splits and repeatability as well as total time. A flatter pace profile at similar effort can be meaningful progress even when the headline time changes little.

Continue improving

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Practical takeaway

Keep the week recognisable while the training emphasis changes across the block. That makes benchmark results easier to interpret and recovery problems easier to spot.

DuoSwim Team

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Caroline

Started the Marathon Plan

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