Elite swimmers make the most of each stroke—here’s a way that swimmers can increase stroke length while also swimming faster.
Stroke length is one of the defining characteristics of fast swimming.
We use it as a proxy for skill and efficiency—the fewer strokes you take to cross the pool, generally speaking, the better of a swimmer you are.
Of course, we aren’t talking about the kind of stroke length (or “distance per stroke”) where a swimmer takes half the strokes, glides forever, and dolphin kicks halfway across the pool.
But the stroke length that reduces drag as we increase swimming velocity. The really good kind.
And one of the ways to get more DPS juice from every stroke is with some targeted resisted swimming.
How Tethered Swimming Can Increase Stroke Length
A really cool study (Skorulski et al., 2026) looked at how technical resisted swimming changed the way that swimmers moved through the water.
Typically, when we think of resisted swimming, it’s buckling extra-wide drag chutes to our waist, filling up multiple buckets on the power tower, or stretching resistance tubing across the pool like a slingshot.
In this case, the goal wasn’t 1RM-levels of swimming.
It was to see if doing a few short rounds of low intensity tethered swimming worked as an activation strategy before a 50 free fast.
Researchers took a group of 32 national-level age group swimmers and compared two pre-sprint protocols. After doing their standard warm-up, they did either:
- Regular swimming – 6×50 free swim at low intensity
- Tethered swimming – 6×10 strokes cycles of easy freestyle on a tether, with 10s rest between reps
During both conditions, swimmers were told to focus on stroke length and awesome body position.
90 seconds later, it was sprinty-sprint time, doing a 50 free from a push-off.
When swimmers used the tether:
- Stroke length increased by 6%
- Swimming speed also increased by 1% (~0.3 seconds)
Swimmers covered more pool with each stroke cycle and also covered it a little bit faster.
How the Tether Changed Swim Technique
Typically, when resisted swimming is used in the pool, it is for straight-up power development or as a priming strategy (e.g. post-activation potentiation). And for most swimmers and coaches, this type of training leading to faster sprinting makes sense.
The nervous system is getting fired up. Swim-specific muscles are primed. You are working the coordination, timing, and force application that goes into fast swimming.
So why did swimming a relaxed and easy intensity on the swim tether lead to faster swimming, too?
Most likely, the tether exposed sloppy force application.
When swimming forward, we don’t really notice how much our pull slips sideways, or we over-rotate, or the hands aren’t at the right pitch to pull through the water.
A swim tether highlights these issues and naturally encourages swimmers to self-organize into a cleaner movement pattern.
The kinematic changes in swimmers’ stroke suggest this is what happened:
- Less side-to-side yaw. Swimmers wobbled less through the stroke.
- Less pitching in the hips. Reduced bouncing when swimming.
- Body roll increased by around ~5%, but roll speed did not change, indicating more controlled rotation as opposed to just twisting harder.
Basically, that added stroke length was simply the result of swimming more cleanly and not extending the arms out further or growing 6” between tests.
The Takeaway
What I love about this study is that it flips a common priming assumption on its head—that swimmers need to go full load, full effort to get a coordination and potentiation boost for faster swimming.
But resisted swimming doesn’t always have to be about max force and power.
At lower intensities, a swim tether (or swimmer’s chute, which may work better as it preserves forward movement in the water, but this was not tested here) is a technical constraint. It exposes sloppy force application and subtly promotes cleaner, more efficient movement patterns.
And when you untether yourself?
Longer strokes. Cleaner movement. Faster swimming.
Which is great news for swimmers who want some of the benefits of resisted swimming without tacking on a bunch of max-effort work.
