The Winter Technique Block: Does Drill-Heavy Swimming Actually Change Your Stroke?

Every November, pools fill with triathletes doing catch-up, sculling and single-arm drills. The idea is sound: the race season is over, there's no event to sharpen for, and the swim is where many age-groupers lose the most time for their effort. A few months of quieter, technique-led swimming should produce a better stroke by spring.

The question is whether it does. Plenty of triathletes finish a winter of drills with a stroke that feels better in the pool and looks the same as last year in a race. This article covers what swim research says about where triathletes' strokes fall short, why technique practised slowly might not survive race pace and fatigue, and what motor-learning research suggests about making changes stick. The honest starting point is that no trial has tested a winter drill block in adult triathletes, so much of the practical section is labelled inference.

TriForward's "Six Months, Same Pace" covers why age-group swimmers plateau, and "Filming Your Stroke" covers video feedback. This piece focuses on the block itself: what it can change, and how to structure it.

Why technique matters more for triathletes than fitness

The efficiency gap

The best-known study on this is old but still relevant. In 1990, Huub Toussaint compared 6 competitive swimmers and 5 triathletes, all highly trained, in Medicine and Science in Sports and Exercise. Using a system that measured how much power each swimmer put in, he compared them at the same power input.

• Gross efficiency, stroke rate and work per stroke didn't differ between groups.
• Distance per stroke was 1.23 m for the swimmers and 0.92 m for the triathletes.
• Speed was 1.17 m/s for the swimmers and 0.95 m/s for the triathletes.
• Propelling efficiency, the share of power that actually moved the swimmer forward rather than pushing water around, averaged 61% for swimmers and 44% for triathletes.

In other words, the triathletes weren't less fit. They wasted more of their effort. Toussaint concluded that triathletes should prioritise technique over their capacity to do work. The sample was tiny and the triathletes were from a different era of the sport, but the pattern is familiar to anyone who has watched a fit cyclist or runner learn to swim.

What changes with speed

Here's the first catch. Technique isn't a fixed thing you have, it's something that changes with speed.

A 2002 study by Millet and colleagues in the International Journal of Sports Medicine filmed 19 elite triathletes and 15 elite swimmers at six speeds from 80% to 100% of their maximal velocity. They measured an index of coordination, which describes the gap between one arm finishing its propulsive phase and the other starting. A negative value means a catch-up pattern, with a pause where neither arm is pushing. Zero means one arm takes over as the other finishes.

• At 80% of maximal speed, both groups swam with a catch-up pattern, at about -9%.
• At 98%, triathletes had moved to about 2.6% and swimmers to about 0.3%, so both had closed the gap between arms.
• At maximal speed, the triathletes' stroke length was 1.70 m against 2.15 m for the swimmers.

Both groups changed their coordination as they sped up. That has a direct implication for drill-heavy winter swimming. A stroke practised slowly, especially with drills such as catch-up that build in a pause between arms, is a different coordination pattern from the one you use at race pace. Inference: technique practised at low speed may not transfer to higher speed unless you also practise it there.

What changes with fatigue

The second catch is fatigue. In a 2005 study in the International Journal of Sports Medicine, Alberty and colleagues tested 17 competitive swimmers with two maximal 25 m efforts before and after an all-out 200 m.

• Stroke length and stroke rate both fell after the 200 m.
• The propulsive part of the stroke lengthened and arm coordination changed.

The abstract doesn't report the size of the changes or the sex split, and these were competitive pool swimmers over a short distance. But the direction is clear: fatigue changes the stroke. A 1,500 m or 3,800 m swim, often after a hectic start, is a long period of accumulating fatigue. Inference: if a new stroke pattern only holds when you're fresh, it probably won't be there in the second half of a race.

What motor-learning research says

Performance in practice isn't learning

The most important idea for a technique block comes from motor-learning research rather than swimming. In a widely cited 1992 paper in Psychological Science, Schmidt and Bjork reviewed experiments on motor and verbal skills and argued that how well you perform during practice is a poor guide to how much you've learned.

• Conditions that make practice look best, such as repeating the same thing many times in a row with frequent feedback, can harm long-term retention and transfer to new situations.
• Conditions that make practice harder, such as varying the task, can slow progress in the session but strengthen what's retained.

The key distinction is between performance (what you can do now, in this session) and learning (what you can still do weeks later, in a different context). A drill set where every length feels better than the last is good performance. Whether it's learning only shows up later, at a different speed, in a different pool or in open water.

Schmidt and Bjork's paper is a review of laboratory tasks, not swimming, and it doesn't prescribe a method. But it explains a familiar experience: a stroke change that feels nailed by the end of a session and has gone by the next one.

Where to put your attention

A second line of research concerns what you think about while practising. A 2021 meta-analysis by Chua and colleagues in Psychological Bulletin pooled studies comparing an external focus (on the effect of a movement, such as the water or an object) with an internal focus (on body parts).

• For performance, 73 studies with 1,824 participants favoured an external focus, with a small effect (Hedges' g 0.26).
• For learning, 40 studies with 1,274 participants favoured an external focus, with moderate effects on retention (g 0.58) and transfer (g 0.58).
• The benefit didn't differ significantly by age, health status or skill level.

Two swimming studies fit this pattern:

• Freudenheim and colleagues (2010), in the International Journal of Sports Science and Coaching, had intermediate swimmers swim 16 m of front crawl with different cues. "Pushing the water back" (external) produced faster times than "pulling your hands back" (internal), and in a second experiment external focus also beat a no-instruction control. The abstract doesn't report the number of swimmers.
• Stoate and Wulf (2011), in the same journal, tested expert swimmers over three 25-yard lengths. Swim times were similar with an external focus and with no instruction, but swimmers were significantly slower with an internal focus on their hands. Swimmers who reported thinking about body parts in the control condition also swam more slowly.

Both were short sprints in pool swimmers, not triathletes swimming 1,500 m. Inference: the cue you use during technique work matters. "Push the water towards your feet" or "keep your hand pressing on the water" is more likely to help than "bend your elbow to 90 degrees".

The research gap

It's worth being clear about how thin the swim-specific learning evidence is. A 2025 scoping review by Minkels and colleagues in Frontiers in Sports and Active Living looked at motor-learning methods for children aged 5 to 12 learning to swim. Of 23 studies:

• 87% reported a positive effect during practice.
• 87% had no retention or transfer test, so they couldn't show whether the improvement lasted.
• 35% had no control or comparison group.

That review covered children, not adults, but it illustrates the problem. Most swim-teaching research shows that people improve during the intervention, not that the change lasts or carries over. No equivalent body of research exists for adult triathletes doing winter drill blocks.

What drills can and can't do

Drills break the stroke into parts, slow it down and exaggerate one element so you can feel it. That has real value for a triathlete who has never felt what a good catch or a long body line is like. But drills have limits:

• Drills are a different movement. Catch-up, single-arm and fist drills change timing, body rotation and speed. The Millet study shows coordination changes with speed even in full stroke, so a drill is further from race pace still.
• The test is full-stroke swimming. A drill is only useful if the change appears in normal swimming afterwards. Practise the drill, then immediately swim full stroke trying to keep the feeling.
• Equipment changes the stroke. TriForward's "Kick, Pull Buoy, Paddles" covers how fins and paddles alter stroke mechanics. They can help you feel a position but shouldn't be where most of the technique work happens.

Inference: drills are a way to introduce a change, not the place where it's learned. The learning happens when the change is carried into full stroke, at increasing speed, while tired.

Building a winter technique block

The following plan combines the studies above. It's inference for triathletes, not a tested programme.

1. Start with an assessment. Get filmed from above and below the water, or have a coach watch you. Pick one or two changes with the biggest likely payoff. Common ones for triathletes are body position, a dropped elbow at the catch, crossing over at entry, and a breathing pattern that lifts the head.
2. Use one external cue per change. For example, "press the water back towards your feet" rather than "high elbow".
3. Move quickly from drill to full stroke. A pattern such as 25 m drill then 25 m full stroke, keeping the same feeling, links the two.
4. Build speed in steps. Once the change holds at easy pace, practise it at steady, then threshold, then race pace. The Millet study suggests each speed is a slightly different stroke.
5. Practise it tired. Put short technique-focused lengths at the end of hard sets, not just at the start of the session. Fatigue is when the old stroke returns.
6. Vary the context. Different pools, lanes, wetsuit swims in spring and swimming in a group. Schmidt and Bjork's work suggests variety slows practice progress but improves retention.
7. Keep some fitness work. A block that's only drills loses the swim fitness that makes a technique change usable. TriForward's "The 45-Minute Pool Session That Actually Makes You Faster" covers session structure.
8. Recheck every four to six weeks. Film again, at race pace and after a hard set. That shows whether the change has become learning or is still only performance.

How long does it take?

There's no good evidence on how long a technique change takes to become automatic in adult swimmers. Inference: given that the Minkels review found almost no retention tests even in children, any specific number of weeks or repetitions you see quoted is likely to be a coaching estimate rather than a research finding. Expect weeks to months for a meaningful change, and expect it to come and go under pressure before it settles.

A triathlon scenario

The following example is illustrative, not drawn from a study. A 44-year-old who learned to swim as an adult swims 1,500 m in about 32 minutes and is fitter on the bike and run. After video analysis in November, his coach identifies a dropped elbow at the catch and a head lift when breathing.

• December: three swims a week, with roughly a third of each session on drills linked to full stroke, using the cue "press the water back" and keeping the rest of the session aerobic.
• January: the same cue, now in full-stroke sets at threshold pace, with four short technique lengths at the end of each main set.
• February: filmed again at race pace and at the end of a hard set. The catch holds at threshold pace but drops when he's tired, so he keeps the end-of-set practice and adds some swimming in a busy lane.
• March: technique work drops to a short slot per session as race-specific fitness becomes the priority.

What's absent matters too: he doesn't spend the whole winter on drills at slow pace, and he doesn't try to change five things at once.

Common mistakes

• Doing drills without full-stroke follow-up. The drill improves, the stroke doesn't.
• Only swimming technique at easy pace. Coordination changes with speed, so the change has to be practised at race pace too.
• Changing everything at once. One or two changes are more likely to stick than a long list.
• Using body-part cues. In expert swimmers an internal focus slowed them down. Cues about the water tend to work better.
• Judging progress by how the session felt. Smooth practice isn't proof of learning. Recheck later, at speed and tired.
• Dropping all fitness work. A better stroke you can't hold for 1,500 m doesn't help on race day.
• Never testing it in open water. Wetsuits, waves and sighting all change the stroke. TriForward's "Learning to Draft in the Pool" covers group and feet swimming in the pool over winter.

Who benefits most

Inference from the Toussaint study: the bigger your efficiency gap, the more a technique block is likely to pay off. Adult-onset swimmers with a short stroke and good fitness from cycling and running are the obvious candidates. Triathletes who swam competitively when young probably have less to gain from technique work and more from fitness. TriForward's "Fixing the Weak Leg" covers whether a winter swim-focus block is worth what it costs the bike and run.

Women and men may differ in stroke characteristics, and most of the studies above either didn't report the sex split or were small. Nothing here suggests that the principles differ by sex or age, but the evidence hasn't tested that.

What we don't know

• Whether winter drill blocks work in adult triathletes. No controlled trial has tested this.
• Which drills transfer best. There's little research comparing specific drills for their effect on full-stroke technique.
• How long changes take to become automatic in adults, or how much practice it takes.
• How well pool technique transfers to open water, in a wetsuit, with sighting and other swimmers.
• The best mix of technique and fitness work for a time-limited triathlete.
• Sex and age differences in learning swim technique.

References

• Toussaint HM. Differences in propelling efficiency between competitive and triathlon swimmers. Medicine and Science in Sports and Exercise, 1990;22(3):409–415. doi:10.1249/00005768-199006000-00020
• Millet GP, Chollet D, Chalies S, Chatard JC. Coordination in front crawl in elite triathletes and elite swimmers. International Journal of Sports Medicine, 2002;23(2):99–104. doi:10.1055/s-2002-20126
• Alberty M, Sidney M, Huot-Marchand F, Hespel JM, Pelayo P. Intracyclic velocity variations and arm coordination during exhaustive exercise in front crawl stroke. International Journal of Sports Medicine, 2005;26(6):471–475. doi:10.1055/s-2004-821110
• Schmidt RA, Bjork RA. New conceptualizations of practice: common principles in three paradigms suggest new concepts for training. Psychological Science, 1992;3(4):207–218. doi:10.1111/j.1467-9280.1992.tb00029.x
• Chua LK, Jiménez-Díaz J, Lewthwaite R, Kim T, Wulf G. Superiority of external attentional focus for motor performance and learning: systematic reviews and meta-analyses. Psychological Bulletin, 2021;147(6):618–645. doi:10.1037/bul0000335
• Freudenheim AM, Wulf G, Madureira F, Pasetto SC, Corrêa UC. An external focus of attention results in greater swimming speed. International Journal of Sports Science and Coaching, 2010;5(4):533–542. doi:10.1260/1747-9541.5.4.533
• Stoate I, Wulf G. Does the attentional focus adopted by swimmers affect their performance? International Journal of Sports Science and Coaching, 2011;6(1):99–108. doi:10.1260/1747-9541.6.1.99
• Minkels C, van der Kamp J, de Vries R, Beek PJ. Learning how to swim in 5- to 12-year-old children: a scoping review of evidence-based motor learning methods. Frontiers in Sports and Active Living, 2025;7:1505301. doi:10.3389/fspor.2025.1505301