Butterfly undulation in Swimming

Reviewer Best-in-class explanation of the mechanics — you'll actually understand why, not just what.

Moderator Fully dedicated, in-depth analysis of undulation mechanics tied directly to arm recovery timing.

Reviewer Real coaching insight — explains why the common cue fails and gives you a drill that works.

Moderator Entirely and precisely about butterfly undulation — what too much looks like, why it costs speed, and how to fix it.

Reviewer Gives you actual drills, not just 'kick from your hips' — the flow drill especially is a good teaching tool.

Moderator Entirely about the hip/core-driven butterfly kick and its timing with the arms — this is the undulation sub-skill by definition.

Reviewer Solid drill, correctly explained, easy to try today.

Moderator The flow drill IS the undulation drill -- fingertip-to-toes wave, hips popping on the kick, fins progression to all positions. Squarely on the skill.

Reviewer Concrete drills from a credible source, clearly explained.

Moderator Directly addresses the undulation: two-beat kick rhythm, and a specific side-lying drill moving the hips forward and backward 'like the worm' to isolate the wave motion.

Reviewer Clear cues and faults — easy to apply on deck.

Moderator Squarely about undulation via dolphin kick, with common faults (head too high, stiff body, knee-kicking) called out clearly.

Reviewer Best-structured lesson in the batch, a real progression, not just tips.

Moderator This is THE undulation video of the batch, the entire lesson is structured around the body wave as the foundation of the stroke, with dryland wave practice, an in-pool drill isolating the wave, and then explicitly connecting the wave to the arms via the chest-up chest-down seesaw cue. Nothing else in this set goes this deep on the wave specifically.

Reviewer Good concrete drills, slightly condensed.

Moderator Same content as the other Stephanie Rice rhythm/kick video - two-beat kick, side-lying worm drill for the undulation.

Reviewer The flow drill breakdown alone is worth the watch — specific and well explained.

Moderator The flow drill described first and in most depth is explicitly the undulation drill, with clear cues on driving the wave from fingertips through the whole body in four body planes.

Reviewer Short and precise from a real coach — wish there was more of it.

Moderator This is literally the undulation drill for butterfly, named and demonstrated directly — forehead-drives-hips-up mechanic explained clearly as the whole-body wave.

Reviewer The 'exhibit A vs B' explanation is genuinely clarifying — best conceptual teaching on undulation in this batch.

Moderator Directly addresses body position and undulation pattern, correcting the common misconception that butterfly is a symmetric up-down dolphin dive rather than a forward-riding wave.

Reviewer Solid breakdown, but assumes you already have a butterfly pull to work with.

Moderator On-topic technical breakdown tying the undulation to the specific phases of the fly pull (X pattern, chest lift, glide).

Reviewer Good starter cue and drill for feeling the wave.

Moderator On-topic — teaches the undulation wave concept with a simple land drill and a pool progression (dolphin kick on back).

Moderator On target: how much undulation is right for the swimmer and the event. More undulation up front buys time to set the catch and lowers the force needed, at the cost of stroke rate and power. Covers tuning the amount, not how to perform the movement.

Reviewer Smart take on tuning undulation - better for refining your fly than for learning it.

Reviewer Explains what an efficient, low-amplitude hip-driven kick actually looks like — good stuff.

Moderator A meaningful chunk of this is real undulation analysis — chest-press-drives-hip-rise, dolphin kick originating from the hips not knees, minimizing vertical amplitude for speed. That's the core of what undulation means in this stroke.

Reviewer Good drill, just very bare-bones.

Moderator Caterpillar drill, arms down, kick initiated from the chest, feel the wave travel -- this is a pure undulation isolation drill.

Reviewer Clear, patient, step-by-step — genuinely one of the better beginner butterfly breakdowns here.

Moderator Covers the full stroke for beginners, with the flow drill and dolphin-kick undulation explained thoroughly as 'the fundamental body position in butterfly' — strong, explicit coverage.

Reviewer Good progression with a nice ribcage-to-feet wave cue, but the drills are named rather than coached.

Moderator Five drills for the fly body wave: dolphin kick on the back (touching ribcage, hips, knees and feet to the surface in sequence), dolphin kick on the front, the same with arms extended, a 2-2-2 timing drill, and fly arms with a flutter kick. Squarely the undulation.

Reviewer Clear, detailed breakdown of the kick mechanics.

Moderator Covers the full stroke but includes a solid, specific section on the kick/undulation - down kick from lower abs/quads, up kick from hamstrings/calves, and 'worming through the stroke' via the upper back/thoracic spine.

Reviewer Good, memorable cues for a notoriously hard-to-feel motion.

Moderator Directly about the dolphin kick — the propulsive core of butterfly undulation — explaining whip mechanics, common kick-size errors, and a kickboard drill to isolate it.

Reviewer One of the clearer full-stroke breakdowns in this batch — she actually explains the wave mechanic well.

Moderator Covers full butterfly stroke — breathing, dolphin kick/undulation, pull — with undulation explicitly explained as a torso-driven wave rather than knee kicking, among other elements.

Reviewer Good for the 'what', not much for the 'how'.

Moderator This defines undulation directly -- the up-down motion in fly and breast, why it exists (breathing), and the hip-driven rotation around the transverse plane. Squarely the concept, even without a drill attached.

Moderator Butterfly built from the body wave up: dolphin-style undulation with the head leading and no bent knees, with a board and then without, then arms, a low recovery, a low breath and two-kicks-per-stroke timing. Undulation is the base of the lesson, though about half of it is putting the full stroke together.

Reviewer Proper progression with cues that stick: no knees in the kick, hips and core drive the wave, eyes down early, kick on thumb brush and hand entry. The arms get more airtime than the wave.

Reviewer Gets the core mental model right, then actually uses it.

Moderator Opens with a genuinely good description of the undulation itself, sine wave, chest initiates and hips and feet follow, not flat like freestyle, before moving on to the pull, breathing and recovery to build the whole stroke around it. Undulation gets real explanation, even if it's one part of a full-stroke walkthrough.

Reviewer Nice drill progression for building the actual feel of the wave.

Moderator A good chunk of this is squarely about the undulation: using fins and the kickboard specifically to isolate hip motion, then the dolphin jump-over-water drill to feel the feet follow the hips. It also spends time on stroke coordination broadly (kicks per stroke, losing the fins), so it's not undulation-only, but the wave itself gets real, dedicated attention.

Reviewer The common-fault list here is exactly what wrecks a butterfly wave.

Moderator The Biondi drill is framed around breathing timing, but it directly touches undulation quality — body position transition, elbow bend, and the 'stay partly dry' cue that governs how much the body should wave through the water.

Reviewer Clear and accurate on the undulation piece, though it's only part of the video.

Moderator This is a full butterfly tutorial covering arm pull, kick timing, and breathing, that explicitly and correctly describes the undulation -- the wave-like hip and body motion tied to the two-kick rhythm -- as part of the broader lesson.

Reviewer Sounds like it comes from someone who actually knows fly mechanics — solid drill framing, just don't expect a deep breakdown in 23 seconds.

Moderator Caption names three real butterfly fundamentals the drill is built to target — coordinated undulation, simultaneous arm recovery, two-kick rhythm — and undulation is explicitly one of those three pillars. It's not the sole focus of the drill, so this isn't a max score, but it's a legitimate 'covers it among other things' hit on the exact named skill, and the terminology is accurate coaching language, which gives me more confidence than a vague caption would.

Reviewer The head-position-vs-hip-sink point is a genuinely useful undulation insight.

Moderator Two of the five 'mistakes' are squarely undulation-related — breath timing driving hip sink, and knee bend degree affecting the kick's resistance/undulation. The other three are arm-pull mechanics. Meaningful but partial coverage.

Reviewer Good motivation to care about undulation, but no how-to.

Moderator Relevant but more conceptual — explains why undulation matters (efficiency, breathing) rather than how to do it.

Reviewer Sharp, specific fix for a mistake almost every new fly swimmer makes.

Moderator Two of the listed mistakes are undulation-specific: the kick-to-stroke ratio (three kicks instead of two throws off your rhythm) and coming up 'too much like a dolphin' (over-exaggerating the wave). The rest of the mistakes (arm symmetry, bent elbows) are about arm technique, not the wave itself, so it's a mixed bag rather than a dedicated undulation video.

Reviewer Good drill-selection reasoning overall, but only a slice of it is really about undulation.

Moderator A tier list of 15 butterfly drills including the 333 rhythm/undulation drill, but that's one of many drills covered (paddles, fins, resistance, assisted speed) rather than a focused undulation lesson.

Reviewer Useful concept buried in a rambling explanation.

Moderator Relevant land-based undulation practice, but the delivery is rambling and hard to follow without seeing it — describes moving from hips/chest/head.

Reviewer Too short to actually teach the difference — more of a visual flag than a lesson.

Moderator Title and caption frame this as a direct comparison of two butterfly execution styles — undulation-driven vs a flatter body line. Since the entire point of the clip is showing what undulation buys you versus a flatter approach, it's substantively about the named skill, even though by definition half the runtime lives with the contrasting 'flat-body' style rather than undulation itself. No transcript, but the caption's topic is unambiguous, so I'm comfortable placing this solidly on-target rather than middling it out of caution.

Reviewer Clear and correct, good early warning against overdoing the wave.

Moderator Directly addresses the undulation with a real, useful correction, don't chase the exaggerated dolphin up-and-down, that just creates drag, focus forward instead, plus the kick-from-the-hips description. It's presented as one step within a full step-by-step stroke guide though, so it shares space with pull, recovery and breathing.

Reviewer Good, slightly counterintuitive correction, just wish it went deeper.

Moderator There's one clear, direct undulation point here, stop chasing the up-and-down and focus forward, the vertical motion should be a byproduct of good technique, not the goal, but it's one paragraph inside a comprehensive video that spends most of its time on timing, recovery, pull mechanics, and breathing patterns by race distance. Touches the sub-skill, doesn't dwell on it.

Reviewer Correct on the wave, just doesn't spend much time there.

Moderator Opens with stroke history (interesting but irrelevant to technique), then a long section on pull mechanics, then the kick section briefly gets at the real undulation idea, the kick originates at the chest and travels down through the core to the hips. That's the right concept, but it's a small piece of a much longer, pull-focused video.

Reviewer Good energy, but not a focused lesson on the body wave itself.

Moderator A general beginner coaching session across multiple strokes including butterfly arm/kick coordination ('pull under, swing') — touches on undulation-relevant coordination but isn't a focused lesson on the body wave.