14/ Underwater propulsion
Most Common Kicking Errors:
1/ PULL AND GLIDE
4/ FROG KICK
- Experienced divers propel themselves efficiently so as to conserve both air and energy.
- Different finning techniques are useful in different circumstances.
- Using several techniques, varying which muscles are used, may help prevent cramping.
- Practicing these kicks on every dive builds muscle memory. They will soon require little thought.
- This presents the smallest surface area to push forward = much less effort required
- Adjusting placement of weights and/or cylinder can help improve your trim.
- Get feedback on your trim from another diver. Self-assessment is unreliable. Video is helpful.
- Proper weighting allows you to remain neutrally buoyant with little or no air in your BCD.
- After getting neutral, practice using breath control to make small adjustments at a given depth, but never hold your breath.
- When your buoyancy good, you will not waste effort finning to adjust your position in the water column.
- Choice of fins may effect your propulsion effort.
- Many divers find split fins inefficient for frog kicking, and ineffective for reverse frog kicking.
- Full foot fins may be less effective than pocket fins, especially in current.
- Opt for comfort and simplicity over style and gimmicks.
- Spring steel fin straps offer almost 100% reliability against losing a fin.
Most Common Kicking Errors:
- Bicycling motion: moves a lot of water so it feels effective, little of this effort translates to forward thrust.
- Using hands/arms for either swimming or stabilizing - very inefficient.
- Keep hands at sides, folded across chest or clasped in front of you. (Exception: 'Pull and Glide', see below)
- Slow down! Relax. There should be no rush to get anywhere underwater. You will see more, extend your dive time, and have more fun.
- Be aware of your trim, your breathing, your gauges, your buddy, and the environment.
1/ PULL AND GLIDE
- A valuable and overlooked propulsion technique when moving along wreckage, or other non-living structure.
- Gives leg muscles a chance to rest and recover.
- Uses very little energy.
- Not using your hands for propulsion is so ingrained in good divers, that this simple method of propulsion is actually taught in introductory technical diving courses.
- A controlled, efficient and deliberate method of propulsion.
- Two fingers may be all that is required to propel you into a glide.
- Look where you are placing your hands.
- Useful for speed and swimming against current.
- Easiest to learn, conforming closely to a natural body posture.
- Though a common technique in open water, it has some drawbacks.
- Uses the big muscles in the hips/thighs, producing good power but also increasing metabolism.
- Causes some side-to-side rotation
- Pushes water downward creating a slight lift
- The downward flow of water may harm marine life.
- In a confined space it will raise silt and ruin visibility, a potential danger in some environments
- Legs straight but not locked at the knees.
- Feet apart just enough to prevent fins from touching.
- Arms out of the way at sides, clasped at waist, or folded across chest.
- Alternate up/down motion with legs, swinging from the hip.
- Execute long, smooth kicks in a gentle, fluid motion rather than short, choppy ones.
- Avoid any tendency toward a 'bicycle motion'.
- Some split fins work best using just the knees (Apollo Bio Fins need speed not power)
- Similar only in the movement of the fins themselves as they alternate up and down.
- Different range of movement: reduced from several feet, to inches.
- Different body posture: Knees bent 90 degrees as for the frog kick (see below), fins horizontal and extending straight back.
- Alternately move each fin up and down in a rhythmic waving motion.
- Uses just the ankle/calve muscles. Avoid dropping your knees.
- Creates little disturbance and allows fine control.
- This kick is also known as the split kick and is favored for its power without the effort of the flutter kick.
- Allows you to swim closer to the substrate without making contact with your fins or stirring up sand or silt.
- The body position looks much like the flutter kick: legs straight, knees only slightly bent. But, the leg motion is quite different.
- Instead of the legs bypassing each other in an up and down movement, the legs are widened and then brought together sharply like a pair of scissors closing.
- Hold in that position for a glide count, then repeat.
- One leg is dedicated to the upper part of the kick, the other for the downward stroke.
4/ FROG KICK
- Most efficient at converting energy expended, into forward motion.
- Avoids disturbing the bottom which damages marine life and reduces visibility.
- A necessity in caves, wrecks, or other restrictive environments, but highly useful all-around.
- Uses smaller muscle groups in calves/ankles = greater efficiency, lowered CO2 output.
- Torso horizontal, knees slightly apart and bent up to 90 degrees, fins flat, pointed back.
- Neck extended, head up, eyes forward.
- Hands clasped in front help you adjust your trim (also allows you to monitor wrist gauges/compass).
- Knees are brought apart, fins rotate out, the thin side edges slicing through the water (loading stroke).
- Ankles now bend inward so the bottoms of your fins face one another.
- Fins are smartly and forcefully brought together (power stroke).
- Glide and then ankles return to original position as you prepare to repeat.
- Restrict the movements of the thighs and knees while letting the calves and a flick of the ankles do all the work.
- Good gentle kick, with not a lot of thrust, ideal for use in caves and wrecks and other confined spaces
- May be reduced even further to a gentle sculling motion for precise slow movement forward with minimum turbulence.
- Among swimmers and freedivers, recognized as one of the fastest and most powerful techniques.
- Because the whole body is used driving the propulsive force, its utility is diminished when we are encumbered by scuba gear.
- Useful if you ever lose a fin, because the feet are held together throughout.
- Fun to add to the mix for variety.
- Try first in confined or shallow, calm water, without scuba gear.
- As you get the hang of it, add fins.
- The whole body drives the propulsive force, delivered through the fins.
- Both feet are held together throughout the stroke.
- Arms are stretched out in front of your head, hands clasped, breaking the water and creating the slipstream.
- Relax your body.
- Requires a coordinated, rapid, undulating motion that begins in the shoulders and chest, is amplified by the mass of the abdomen and hips, finally being transferred through the lower body to the fins in whip like fashion.
- The knees alternately bend and then straighten out on the power stroke.
- There is little glide component, making this a highly energetic technique.