>But whether you're a beginning diver or an experienced one, perhaps the most important thing you can do to improve your diving is to master the ability to be neutrally buoyant and maintain a stable, horizontal position — also known as good trim — throughout the dive.
>These skills are not learned overnight or through a training course alone. Without practice most divers find it difficult to maintain neutral buoyancy for more than a few moments while holding perfectly still, and many swim in a head-up, feet-down attitude (or position), which leads to excessive exertion as they move through the water.
>But for those willing to do the work, the rewards are dramatic. Divers who perfect these techniques experience less fatigue, reduce their gas consumption, may learn new skills more easily, safeguard the environment and benefit from improved confidence and control underwater.
>Good trim is also essential in caves. By maintaining a streamlined horizontal orientation with the head forward, the legs bent at the knees and the feet elevated, divers minimize their surface area in their direction of travel and can therefore move through the water with less resistance. This reduces workload and gas consumption. Furthermore, movement up or down while horizontal is subject to greater resistance, which further enhances divers' ability to control their position in the water column.

>Most training agencies now offer a course or a module that addresses good buoyancy and trim (see sidebar). However, many divers have yet to get the message. Pick up a dive magazine or visit a popular dive site and you will see divers struggling through the water in "seahorse" position or a circle of divers kneeling on the seafloor to do drills. But the message is spreading. Recently the Professional Association of Diving Instructors (PADI), the world's largest training agency, announced that it would begin emphasizing trim and buoyancy in its revised open-water training program beginning in 2014.
>Good buoyancy and trim means being able to descend slowly in a horizontal position and then stopping at will without touching the seafloor or sculling with the hands. From there, the diver should be able to start swimming without breaking position or float motionless for several minutes in a horizontal position without rising or sinking. Divers should be able to clear their masks or share air with a dive buddy while maintaining good trim and without changing depth by more than a few feet. They should also be able to turn to the left or the right or even move backward using only their legs.
>One training method that can help you master these skills is the use of performance metrics. For example, specify a number of feet you may vary from your target depth during a training exercise or quantify in degrees how far you wish to permit yourself to deviate from horizontal (e.g., no more than 20° or 30°). Metrics offer a precise way to track and measure performance instead of relying on qualitative judgment alone.
>A second method is using video to record your (or your students') training exercises to get accurate feedback about progress. Video enables you to see what you're doing right and what needs work. Underwater mirrors, which are sometimes used in pool practice, are also excellent feedback tools.
>Typically the first step in training is making sure you have the right equipment and that it's adjusted properly. Some divers find that traditional jacket-style BCDs tend to lift the upper part of the body, making it more difficult to maintain a horizontal position. For that reason, divers who desire a more horizontal attitude may prefer a back-mounted BCD or wings.
>Maintaining proper trim is also more difficult if you rely solely on a conventional weight belt. The best approach is to distribute weight around your torso. This can be accomplished by using a stainless-steel back plate, a steel tank and/or keel or tail weights.
>Finally, it's important not to be overweighted, which necessitates putting more gas into the BCD, which increases drag and, thus, the energy required for swimming. Weight yourself so you are able to hold your position in 10 feet of water when your tank is nearly empty.
>Frog Kick: The frog kick is the kick used when swimming the breaststroke. The legs mirror each other. This kick is powerful enough to be used in strong currents, and it's relatively easy on the leg muscles, so it can be maintained for extended periods.
>Flutter Kick: In contrast to the open-water flutter kick, the bent-leg flutter uses only the lower half of the legs for propulsion. Keeping the knees bent, the diver kicks and recovers one leg and then the other in rapid succession, initiating movement from the knee joint. The movement is completed by the ankles, which whip the water back and up with each cycle. The hips and thighs stay motionless throughout and should not dip below the horizontal plane of the body.
>Back Kick: The back kick is extremely useful for adjusting and maintaining your position relative to your dive buddy, the reef, a wall or a shipwreck. It's an essential kick for instructors, cave divers and underwater photographers. The kick applies the same concept as the frog kick but in reverse. It's a challenging but worthwhile kick to learn.
>Helicopter Turn: The helicopter turn enables divers to turn completely around without breaking horizontal trim or flapping their arms. As a result, the turn minimizes the movement of gas in your BCD or drysuit and therefore helps maintain stability. The movement is essentially a combination of the back kick and the frog kick. One foot completes one of the movements before the other foot starts the other one, and the diver pivots around a vertical axis without dropping the lower back or the knees.
>Global Underwater Explorers: GUE Fundamentals
>International Association of Nitrox and Technical Divers: Essentials
>National Association of Underwater Instructors: Introduction to Technical Diving
>Professional Association of Diving Instructors: Peak Performance Buoyancy
>Scuba Schools International: Perfect Buoyancy
>Technical Diving International: Intro to Tech Diving
>Unified Team Diving: Extreme Scuba Makeover
>© Alert Diver — Fall 2013