The fish kick may be the fastest subsurface swim stroke yet (2015)

Hydrodynamics and the “fish kick”

• The fish kick is essentially a sideways dolphin kick; rotating 90° lets the swimmer avoid constraints from the water surface and pool bottom.
• Commenters connect this to fish locomotion: oscillating “fins” shed contrarotating vortices (Kármán vortex street), allowing partial energy recovery and efficient propulsion.
• Efficient swimmers behind another can draft, using the front swimmer’s wake like a peloton in cycling; even slightly offset positions in open water save energy.
• Some argue side lanes may suffer more from chaotic, unstructured turbulence reflected from walls, making middle lanes faster.

Lane Advantage and Fairness in Competition

• It’s widely acknowledged that middle lanes are advantageous; in major meets these go to the fastest qualifiers.
• One side defends this as “earned advantage” that incentivizes doing your best in heats and avoids sandbagging for better positions.
• Others argue it creates a positive feedback loop and undermines equality at the start; proposals include random lane draws, unused buffer lanes, or time corrections—but these are seen as hard to calibrate.
• Broader analogies are drawn to F1 grid rules, rally starting orders, NFL home-field advantage, and draft systems that add negative feedback across seasons.
• Spectator interest is cited: many prefer systems that maximize records, dynasties, and clear favorites over perfect fairness.

Stroke Rules, ‘Freestyle’, and Underwater Limits

• Some find it odd that swimming awards medals for constrained, slower strokes, likening it to 100m skipping or backwards running. Others respond that different strokes have distinct functional value (sighting, breathing, open water).
• Several want a “true freestyle” event with no stroke restrictions and no 15m underwater limit.
• The 15m rule (and similar constraints) is variously explained by:
  • Safety concerns (historical blackouts when swimmers stayed under too long).
  • Poor optics and harder officiating for fully underwater races.
• There’s also debate over clothing restrictions: they preserve fairness and avoid a tech arms race, but clash with the idea of unconstrained “freestyle.”

Biomechanics, Evolution, and Alternative Movements

• Commenters contrast running (where evolution has largely fixed an optimal form) with swimming, where humans have no evolved high-speed stroke, leaving more room for technique innovation like the fish kick.
• Discussion branches into which terrestrial mammals are good swimmers and whether human quadrupedal running or advanced climbing show that “unnatural” gaits can sometimes be efficient.
• Some speculate about future improvements via optimized movement patterns or even body-shape optimization, while noting that finswimming and freediving already explore more “aquatic” configurations outside Olympic rules.