Swimming performance: lateral thinking for better starts

Why could a lateral entry prove advantageous compared to a conventional water entry? Well, the inspiration for the lateral entry technique comes from a study on the Fosbury-flop high jump technique, showing that body rotation during take-off is conducive to more power from the take-off leg, thus increasing the height of take-off⁽⁴⁾. In theory, more power off the blocks equates to greater acceleration, which in turns means higher speeds through the air and a faster time to reach the initial 5-metre distance. Furthermore, a lateral entry should involve a smaller gradual displacement of water during entry. In very crude terms, the entry shoulder ‘pushes water out of the way’ allowing the uppermost and following shoulder to enter with less resistance and less drop in speed. This is in contrast to a lateral entry, where both shoulders have to push water out of the way as the water surface is broken.

Does lateral entry work?

Theory is all well and good, but does the theory on lateral entry translate into improved performance in the pool. In the 2023 study above, the Chinese researchers out their theory to the test. Twelve elite swimmers (six female, six male) volunteered to participate in the study, all with PB times that were within 90-96% of the world record in the best event (ie highly elite!). After familiarization, all the swimmers underwent repeated testing for race starts using both traditional and lateral water entry techniques. For both types of starts, the researchers recorded a number of parameters using 3D force platforms on the blocks and high-speed cameras – both above and below water. These included:

·        Block phase duration

·        Take-off angle

·        Flight distance

·        Entry angle

·        Entry velocity

·        Maximum depth

·        Time to the 5-metre mark

·        Average power from starting signal to take-off

·        Horizontal force applied to the block on take off

·        Vertical force applied to the block on take off

When they compared the data from the ordinary entry and lateral entry techniques, there were five key parameters that showed a significant difference when using the lateral entry technique. These were as follows:

·        A smaller (shallower) entry angle, which was decreased by around 1 degree.

·        A shallower maximum depth (a decrease of around 0.42 metres – a big change).

·        A faster time to the 5-metre mark.

·        A greater horizontal push force off the block combined with a decrease in vertical force.

The overall effect of these differences resulted in the lateral entry technique being significantly faster than the ordinary entry technique, resulting in 0.06 seconds (3.39%) time decrease for swimmers at the 5-metre distance mark. This was almost certainly due to the greater horizontal propulsion off the blocks, leading to higher through-the-air velocities, combined with an efficient water entry. The researchers naturally concluded that their preliminary results from 12 elite-level swimmers showed that a lateral entry technique is advantageous compared to the ordinary entry technique.

Training for lateral entry

That the swimmers achieved faster times to the 5-metre mark just by performing lateral entries on demand as part of a study is impressive enough. But given all these swimmers had been training for years using the traditional water entry technique, the researchers wondered whether training and perfecting the lateral entry technique would lead to additional performance gains. The answer to this question can only come from data acquired in a study, so this is exactly the researchers did!

Published in the journal ‘Sports Biomechanics’, this study investigated the effects of eight weeks of lateral entry training on the start performance of elite swimmers, and its impact on ordinary entry performance⁽⁵⁾. As in the study the year before, the researchers collected data from 12 elite swimmers using a 3D force platform and high-speed cameras, which analyzed 19 parameters of ordinary and lateral entry. However, in this study, the swimmers worked on perfecting their lateral and traditional entry technique over an 8-week period and then the pre-post results were compared. Importantly, the swimmers practiced both entry techniques so that the comparison reflected the swimmers’ normal training patterns, and so that any advantages seen in the lateral entry were down to the technique itself rather than lack of finesse when executing a traditional entry.

What they found

When the data was analyzed the key findings were that, compared to ordinary entry, the lateral entry performance was characterised by:

·        A decrease of vertical force (by 5.77%).

·        A reduction in maximum depth (by 6.09%).

·        An increase in the lateral ‘push’ force of 14.06%.

·        An increase of ‘flight in the air’ distance of 4.33%.

·        An increase in the ‘first kick’ distance of 3.90%.

What really matters however is performance, and here the findings didn’t disappoint. The results showed that, compared to an ordinary entry technique, the lateral entry technique provided a 3.93%, 6.14%, and 8.29% reduction in time to reaching 5m, 10m and 15m distances respectively – ie very significant performance improvements in start times. Moreover, when they compared pre- and post-training results for normal entry, it was clear that the 8-week training period on the lateral entry technique did NOT have a significant impact on the time performance of the ordinary entry technique, suggesting that swimmers who try and prefect a lateral entry technique have little to lose because it won’t interfere with their normal technique.

Practical implications for swimmers

These recent findings provide powerful evidence for the potential benefits of a lateral entry technique when launching off the block. The key factor seems to be that by applying some rotational force when launching, more horizontal force can be applied, and the flight phase can be made faster with more distance covered. In addition, a non-horizontal water entry can be cleaner, resulting in faster speeds during the glide.

If you want to try adopting this technique with some practice sessions, there seems little to lose, particularly as it’s unlikely to interfere with your conventional start technique. Should you choose to rotate clockwise or anticlockwise when trying this technique? This will depend on your dominant leg strength; those who are left-leg dominant will probably find it more natural to rotate anticlockwise while those who are right-leg dominant will likely prefer a clockwise rotation direction.

However, given this approach is novel, there are no hard and fast rules and experimentation is key. It’s also worth adding that every swimmer will be different and you may find that your own technical preference maybe to continue with a more traditional entry. The key to know whether switching to a lateral entry technique is right for you is of course, measurement and feedback. If you see your flight distance getter longer and your times getting faster, you will know it’s working!

References

1.       Cossor, J., & Mason, B “Swim start performances at the Sydney 2000 Olympic Games”. ISBS-Conference Proceedings Archive; 2001. ojs.ub.uni-konstanz.de/cpa/article/view/3870

2.       European Journal of Sport Science 2018; 18(10), 1317–1326

3.       “Is lateral entry beneficial to elite swimmers? A preliminary study.” 41st International Society of Biomechanics in Sports Conference, Milwaukee, USA: July 12-16, 2023

4.       Dapena, J: “The evolution of high jumping technique: Biomechanical analysis” ISBS-Conference Proceedings Archive 2016. ojs.ub.uni-konstanz.de/cpa/article/view/657

5.       Sports Biomech. 2024 Sep 16:1-16. doi: 10.1080/14763141.2024.2400531. Online ahead of print