When you speak to top open water swimmers the vast majority do a lot of their training in pools. Although there is no substitute for getting experience in a range of conditions in open water swimming, its also generally true that pool training is an efficient way to build fitness and work on technique., especially if you have a pool nearby.
Unless you’ve hit the jackpot of living and working by the beach, for most people its easier to sneak in a swim in the pool than getting to the coast or a lake. And when you add in the ‘luxury’ of indoor changing rooms and hot showers pool swimming can quickly become tempting, especially in the depth of winter.
pool swimming can be enjoyed as part of a balanced open water swimming lifestyle
Just like the confectionery industry says sweets can be enjoyed as part of a balanced diet I would argue that pool swimming can be enjoyed as part of a balanced open water swimming lifestyle. Provided that you make the effort to get to the beach and lakes when you have time to enjoy swimming outdoors and develop more experience in a range of conditions, then additional pool training can only be a good thing to build technique and fitness.
For fitness the pool is great as its a safe environment with virtually none of the dangers you have to worry about when open water swimming, there will probably be a lifeguard only a few meters away. This means you can push a bit harder, especially for threshold and anaerobic work which is great training in the run up to a race. Unlike open water I recommend shorter interval work in a pool, which will be also be a lot less boring.
For technique the pool is also great as it gives a safe and consistent environment to hone in on specific skills with 100% focus. Getting a long and smooth stroke with no dead spots is a lot easier to master in the pool than in the turbulent surface water of the choppy sea. Even techniques used by racers cross over really well to open water swimming, for example the breakthrough when racers come up to the surface after a turn or dive is the same as punching through a big wave in the sea and keeping your speed as you get back to the surface.
the breakthrough when racers come up to the surface after a turn or dive is the same as punching through a big wave in the sea and keeping your speed as you get back to the surface.