Swimming - Underneath the Water

You Don’t Know What You Doing.

“Guessing a thing aint knowing a thing” – Patrick Ness

Most swimming coaches can stand poolside and develop a fairly good idea of what their swimmers are doing or not doing. Although experience improves this ability, what often gets forgotten is the fact that much of this is based on assumption or educated guessing. The water can be very deceptive when it comes to movements beneath the surface.

Looking at swimming technique from above the water doesn’t paint an accurate picture of below the surface.

With most of the body beneath the surface when swimming, looking at technique from above the water can look very different from what it looks like from beneath the surface. Scientifically speaking, refraction at the boundary between water and air bends light and causes objects and depths to appear slightly differently to what they really are. Add to this the waves and splashes that get in the way and the speed at which a decent swimmer swims, and a coach is fighting a losing battle with it being nearly impossible for the human eye to accurately see and analyse motion in split second intervals.

Perspective from the swimmers themselves is also not a reliable benchmark.

From the swimmers’ perspective, feeling is also not reliable because our bodies lie to us. What they feel and believe they are doing can sometimes be a far cry from what they are really doing. Seeing themselves in a video is often a lightbulb moment when they see something they had no idea they were doing.

Analysing underwater video is the best place to start with improving technique.

Underwater video is undeniably the best way for any swimmer and/or coach who is wanting to improve technique to figure out what is really going on. It gives the coach the opportunity to view a swimmer from angles they do not usually get to see and to progress slowly through the strokes to better detect strengths and weaknesses. It gives the swimmer the opportunity to merge what they feel with what they see. And it provides a more accurate picture of what is really going on and allows for more informed decisions when it comes to technique.

An underwater assessment should be done once a season at the very least.

Don’t be fooled – looking at technique just once off is simply not enough. Although we all wish it was, good technique is not permanent. Once you master a technique it is not just set in stone and with you forever. It requires constant work and will inevitably change and fluctuate over time. This commonly occurs due to physical limitations such as injuries or functional movement changes, the tenacity of habits which inevitably resurface, miscommunication during feedback, and inaccurate body awareness. An underwater assessment should be done at least once a season at the very least.

Know what you are doing!

Body Position

Body Position

Hand Entry




Amy Bathgate
About the Author
Amy Bathgate is the Operations Manager at VS Sports, playing an integral role in product development, innovation, and design, and heading up a team of enthusiastic analysts working towards transforming the way sport is analyzed, scouted, and experienced. With over a decade of expertise in consulting, biomechanics, and performance analysis across various disciplines and levels, she understands that the little details make a big difference. One of her passions and specialties is swimming, and she assists and drives athletes and coaches to achieve their performance potentials using stroke and race analysis to better their understanding of the complexities of the sport in order to go faster and train and perform more efficiently. Amy is also a Dartfish Certified Instructor, certified in Functional Movement Screening, and a former lecturer at the University of Pretoria.