The time to perform a lap consists of several components. You can calculate lap time using following formula: Lap time = Underwater time + Turn time + (stroke count / stroke rate).

Figure: the laptime breakdown.

In previous blogs, we discussed turn time, stroke rate, and stroke count. Today we take a closer look at the last parameter that is needed to calculate lap time, namely underwater time.

Free style, back stroke, breast stroke, and butterfly are the 4 most known, and used, strokes. But, there is a 5th stroke, that needs a lot of attention and practice while training. This 5th stroke concerns the underwater stroke, also known as the dolphin kick. Training your dolphin kick will improve your underwater time.

Figure: In butterfly and breaststroke, turn time starts when you touch the wall.

Underwater time is the phase, in the beginning of a lap, that you enter after a turn and push-off. It is the time you spend under water between this push-off and doing your first stroke. This underwater time is very important because it takes up a large part of your total lap, especially in a short distance pool (25m). The proportion of the underwater time versus total swim time is way bigger in a 25m pool than for instance a 50m pool, that is why the main focus of this blog will be the short distance pool.

In races you can swim up to 15m underwater. The aim is to reach this mark as close as possible. The ratio 15m of 25m is very big, that is why it is such an important skill to control. When looking at a 50m pool, the swimming time becomes more important, because the ratio 15m of 50m underwater is way smaller. Depending on which pool you are going to race, you should focus on training your swimming time or underwater time. Of course, by mastering both skills you will become a great swimmer.

Why train underwater time?

When swimming underwater, the body experiences less resistance. Because of this, a swimmer is able to swim fastest underwater. That is why you want this distance to be as long as possible. By training your underwater time the distance you swim underwater will gradually increase. Besides swimming a long distance underwater, you want to be able to swim this distance as fast as possible. This can also be trained. Optimize your underwater time to the point where you need the least time to swim your longest distance underwater. Make sure to use a good push-off to set you of a wall, because this will give you momentum you will need during the underwater time.

Technique drill.

Controlling your breathing is an important aspect of mastering your underwater time. Because this phase takes so much effort, you would normally be out of breath quite fast and would not be able to make a long underwater time. By training to control your breath, your underwater time will improve. A great way to train this is by using a drill. This drill is made out of 4x 75m in a 25m pool, while performing a stroke of choice.

• First 75m – 25m underwater + 50m swimming
  
  Begin the underwater phase starting from the wall. Swim the last 50m with perfect turning points.
  
  
• Second 75m – 25m swimming + 25m underwater + 25m swimming.
  
  Swim 25m with a perfect turning point, then go into underwater phase, and finish off with 25m swimming. This will be harder than the first 75m because you first swim 25m before going into your underwater phase.
  
  
• Third 75 – 50m swimming + 25m underwater
  
  You have 2 turning points before entering the underwater phase.
  
  
• Fourth 75m – normal swimming with after every turning point 15m underwater.
  
  Swimming steadily, with after every perfect turning a new underwater phase.

Between every set, there is a rest period of approximately 10 to 20 seconds, depending on your personal level of swimming. Aim to reduce this rest time bit by bit. Besides this, try to build up your underwater time, going from 10m to 25m. Executing this drill will help train and improve your underwater time. However, it is important to understand that underwater time measures the proportion of the time you spend underwater compared to the total swimming time. The outcome of this proportion will decide whether to focus more on one parameter, rather than the other, during training.

Take home message

It is important to understand that underwater takes time to train. If, in the past, you lasted for instance 3m underwater, don’t expect to swim 15m underwater during a race without practice.It takes time and dedication to improve underwater time, and to get control over your breathing. Because this can get quite tough, using a drill will help you with this training. Performing a good push off the wall will create momentum that will benefit your underwater time. Train for an increased underwater distance, and to decrease the time spent on this distance.

Swimtraxx One can measure underwater time in real-time. Because every breakout counts Swimtraxx One helps you get a clear view of your hypoxic effort for every lap. Swimmer and coach can find all the measured data on the Swimtraxx app. This gives the opportunity to focus on swimming and underwater technique rather than having to collect the data yourself.

Thank you for your interest in this blogpost. Be sure to keep an eye out for new blogposts as we will regularly be adding swim specific content. We have some tips and tricks scheduled as well. If you wish to stay updated about our news, subscribe to our newsletter below and never miss a thing.