Getting into the wetsuit is one third of the strength workout. The swim is the second third. And getting your wetsuit unglued from you without shredding it, is the last third of your strength workout for the day. What you need to take away from this equation is that swimming in open water is much more strength oriented than your peaceful glide through the swimming pool.
Wetsuits are a great thing for triathletes largely due to the fact that your legs conveniently self float. While this puts you in a hydrodynamic flat position, it causes your stroke to be subtly different from what you achieve in a swimming pool. Being more horizontal in the water means that you use a slightly different range of motion in the stroke phase of your stroke. This will mean that the start and end of your catch phase is employing a slightly different set of muscle firing. Due to the high number of strokes you take in a swim workout, this slight change in muscle firing requires some adaptation in terms of developing necessary arm strength.
Furthermore, an extra amount of power output from your back and shoulder muscles is needed to overcome the restriction of your wetsuit material. As a result, your shoulders have the potential to become rather worn out from open water swimming. Building up this strength is key in developing your abilities as an open water swimmer. Adding in an open water swim in whatever local body of water is available to you is immensely helpful to become comfortable with the positioning of open water swimming as well as the strength requirements to overcome the wetsuit restrictions.
Lastly, unlike a swimming pool, open bodies of water don’t have a black line conveniently painted on floor for you to follow. In order to navigate yourself through an open water swim, becoming proficient at “sighting” is a necessity. Sighting requires a swimmer to pick an unmoving object to aim at on the horizon. From this point, the swimmer then swims towards the object, and periodically picks up his/her head to check that the object is still on the chosen trajectory, and keep swimming- all without causing a huge glitch in the swim stroke or body position. The biggest issue with sighting is that lifting the head causes the legs to sink. With practice, a swimmer can learn to sight with minimal impact on body position in the water- but it does NOT come naturally. The more practice you can get sighting, the more comfortable you can become with the process of choosing a good object to aim at, and then following a trajectory without having to sight more than once every several strokes. Common mistakes often involve choosing a moving object such as a person or sighting too often. These mistakes can lead you off course and drain you of energy.
Open water swimming requires some practice on several fronts. However, if you have spent time working on your stroke in the swimming pool, the transition can be made fairly smoothly to open water. Adding in dry land swim strength training, and making a strategy for sighting based off your specific swim course can help get you prepared before you set foot in the water. Keep an eye out for a blog post that tackles tricks and tips for different open water swimming environments!