Swimming Start Trajectory

This article will look at swimming start trajectory. There is a link between overall swimming performance and the dive at the start of the swim. In fact, depending on the race it can equate to 0.8 and 26.1% of the total swim time. Taking this in to account, it’s important competitive swimmers fully train the swimming start.

The swimming start is defined from the starting signal to when the swimmer’s head reaches the limited 15m marker. Typically, elite swimmers start ranges from 5.5 to 8 seconds. We have already discussed ways in which you can improve your reaction out of the block on a previous article.

For the purpose of this article, we can break the swimming start down in to three phases:

  1. Block
  2. Flight
  3. Underwater

For elite swimmers, the average % of contribution spent on the block is 11% (0.74 seconds), 5% is spent on flight time (0.30 seconds) and 56% is spent in the underwater phase (3.69 seconds).

The Perfect Dive

At this point, it is important to note that the fastest to enter the water isn’t necessarily the fastest starter. Here, it is important to maintain the highest velocity for the longest period of time after the swimmer has entered the water.

The key to a good swimming start is to reduce reaction time (hard to do and I believe better training other elements of the start), whilst increasing horizontal velocity to optimise the under-water phase.

There are number of factors that can affect the velocity after the swimmer has entered the water. These include:

  1. Streamline (including frontal drag)
  2. Starting underwater undulating dolphin kick at around 6m
  3. Generating force from propulsive kicking action

The depth of the underwater phase can affect the amount of drag that acts on the swimmer and therefore affects the trajectory of the swim. For example, if the swimmer is too deep at the start then it will take longer to swim to the surface. On the other hand, if the swimmer is too shallow then they experience an increase in drag forces that are acting upon them. Likewise, the timing of the first kick is important as too early will increase the amount of drag. Also the velocity of the entry of the start <6 would be faster than what a swimmer could kick anyway and therefore would be seen as wasted energy output.

We can therefore state that the timing of the first swimmers kick, depth and trajectory are the biggest influences in overall start performance of a swimmer.

Water Trajectory

The optimal water trajectory depends on the swimmers anthropometric make-up and underwater kicking. Below is a set of recommendations of a swimming start:

  1. At least 0.5m under the surface
  2. Maximum depth of 0.8m and 1m
  3. Hold glide for 2 seconds
  4. Start underwater kicking from 6.5m

Whilst individual ability and characteristics should be taken in to account, these recommendations should help form the basis of a higher velocity swimming start, equalling a better starting performance.

We can help you with your swimming starts through a structure, land-based training plan. Contact us for a free consultation today. We offer online 1-1 online training and also a number of training plans.

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