Swimmers rely on efficient technique to get their chlorinated bottoms to the other end of the pool without cranking up the energy cost.
The more efficient you can swim, the longer you can swim, and when combined with added force, the faster you will go.
To improve technique, swimmers often turn to drills. Whether it’s single-arm to work rotation, closed fist to improve forearm position, or long dog paddle to dial in the catch, the stated goal with drills is to boost full-stroke efficiency.
An alternative to drills is using resisted or tethered swimming at low intensities. Which sounds counter-intuitive. Resisted swimming tools like chutes, tubing, tethers, and power racks are typically used to increase stroke power and strength.
But used at a lower intensity, it is a constraint that naturally promotes better technique.
Here’s how this happens.
Resisted Swimming Strengthens the Feedback
To understand why resisted swimming can be triple-A awesome for better technique, it’s helpful to look at how the way we interact with the water changes when we add load.
In regular swimming, when we move forward through the water there is a continuous flow around the body. This flow provides feedback which guides our decisions on where we position our arms and legs and how we roll our body.
But when we use a really asymmetrical pull, or roll too far, or the hips sink, the consequences can be so subtle that we don’t really process it. Momentum has a way of covering up these technique mistakes.
By adding load or a tether, forward velocity decreases big time (or to nearly zero in the case of a tether). That stabilizing flow disappears and now lateral or inefficient movements that went undetected create a much stronger signal.
Asymmetry in the pull, excessive roll, propulsive gaps in the arm cycle—these things get felt immediately and obviously. Even if you aren’t actively thinking about it, your body is smart enough to self-organize in response to inefficient movement.
And that’s what makes tethered/resisted swimming such a powerful technical tool—stroke errors get amplified, which gives the nervous system a stronger corrective signal, which then opens the door for swimmers to solve the problem in a way that is superior to drills.
How Tethered Swimming Changes Technique
That all sounds lovely, but how does this actually work?
A couple of studies looked at exactly this idea—low intensity tethered swimming—to see what kind of impact it had on technique and swimming performance.
The first study—Skorulski et al. (2025) examined the effects of two months of “technical tethered swimming” with a group of swimmers. Once per week, swimmers did the following set:
- 6×10 tethered stroke cycles + 10 seconds rest
- 150 freestyle swim with a snorkel
There were no specific ongoing technique cues or commands—swimmers were only told to swim at low intensity (well below threshold) and to focus on a long stroke and slow execution of movements. No sprinty stuff.
Alongside the tethered group, a control group did 45 minutes of freestyle drills, including classics like one-arm freestyle and catch-up.
After the two months, the tethered group of swimmers had significantly more stable body position in the water, including:
- Better control when turning to the non-dominant side to breathe
- Reduced excess body roll
- Less lateral movement
The control group, which did 45 minutes of your standard freestyle drills each week, went the other direction, increasing yaw rotation, body roll, and increasing rotation speed (not a good thing, in this case).
Drills seemed to reinforce existing technical errors (also not a good thing).
The tethered group, with no drills or specific technical cues to do so, naturally shifted towards a straighter, cleaner bodyline when swimming.
Tethered Technical Swimming Can Boost Stroke Length
Stroke length is one of the ways that swimmers and coaches track efficiency in the water. Loosely speaking, the fewer strokes you take, the more efficient your technique, the faster you are going to go.
Another, more recent study (Skorulski et al., 2026) by the same group of researchers looked at the immediate effects of low-intensity tethered swimming.
Using a crossover design, swimmers either did:
- 6×10 stroke cycles while tethered + 10s rest
- Low intensity with a focus on stroke length and good body position
Or:
- 6×50 swim freestyle
- Low intensity, same technique focus
Right after, swimmers did a 50m freestyle all-out. And wouldn’t ya know it, the tethered condition produced some interesting technique changes:
- Stroke length increased by a significant chunk—about a 5% jump
- Swimmers showed less side-to-side movement
- Better body alignment (less up and down movement in the hips/pelvis)
- Improved 50m freestyle times by ~0.30 seconds
Given the popularity of post-activation potentiation work with swimmers, this presents an alternative way to “prime” swimmers for a good set, time trial, or potentially a race.
PAP protocols typically require max effort, high-stress movements to create that potentiation window—this study suggests that some of that same good stuff can be generated without having using max intensity.
Along, of course, with the technique benefits.
The Bottom Line
The fun takeaway from this concept is that it’s not about making the stroke harder, but making stroke mistakes easier to feel.
By adding resistance, we amplify those sneaky lateral movements, wobbles, excessive rotations and ineffective force applications.
- A crooked pull gets more crooked
- Excessive body sway becomes more obvious
- Sagging hips try to get soggier
- Propulsive gaps in the stroke get you pulled backwards
There’s so much that goes into efficient technique. One of the problems with drills is that when you try changing one part of the stroke, you end up changing something else.
Applying the constraint of resistance gives your body a chance to self-organize in a way that naturally promotes better technique. And it’s done within the context of full-stroke swimming instead of isolating something and trying to jam it into your stroke.
Give it a shot at the pool this week, let your body solve the challenges of moving more efficiently through the water, and tether yourself to better technique.
ABOUT OLIVIER POIRIER-LEROY
Olivier Poirier-Leroy is a former national level swimmer, 2x Olympic Trials qualifier, and author of several books for swimmers, including YourSwimBook, Conquer the Pool, The Dolphin Kick Manual, and most recently, The 50 Freestyle Blueprint.
The book is a beastly 220+ pages of evidence-based insights and practical tips for improving freestyle sprint speed.
It details everything from how to master stroke rate, technique, build a thundering freestyle kick, improve your start and underwaters, and much more.
The 50 Freestyle Blueprint also includes 20 sprint sets to get you started and a bonus guide on how to master the 100 freestyle to complete your sprint preparation.
👉 Learn more about The 50 Freestyle Blueprint today.
