DSC_4063Curiosity and a drive to find out more about how swimming can be more efficient, how swim technique can be improved and how to train smart is what drives me in my daily work as a coach. Throughout the years I have been involved in different projects with stroke analysis such as video analysis, and more recently with force measurements in the water.

In 2019 the question I was pondering was if there is a correlation between how much force a swimmer can generate on land and how much he or she can then generate in the water. If a swimmer can perform strength exercises on land and really generate a lot of force while doing them, does it automatically mean that they can use that same amount of force in the water?

Together with Jack Fabian (PhD and Coach), Rob Sleamaker (CEO of Vasa Inc) and Ari Auvinen (Chairman of Trainesense), I set out to get some insights into this question. In December Jack and I tested a few swimmers’ force development on land on the Vasa SwimErg and then their force development of each stroke in the water with the SmartPaddles from Trainesense.

Foto 2019-12-17 21 19 05 (1)

The questions we had were:
1) Is there a correlation between being able to generate a lot of force or power on land, and the ability to produce force or power in the water?

2) Does higher force development correlate to faster swimming velocity? If yes, then the swimmer that can generate the most force on land (in a similar motion as swim stroke) should be able to generate the fasters swim velocity.

3) Will improving power on land automatically mean an improvement in the water?

4) Is a decrease in force development in the water due to an increase in resistance (surface area)? If yes, then the same decrease in force should not be seen on land measurements.

avg power vs spm vasa

Insights from the tests:
1) Yes, for the swimmers tested there was a linear relationship for the relative change in force and relative change in power that indicate that there is a correlation between the ability to develop force on land and in the water.

2) Yes, for the swimmers tested the ability to generate a lot of force on land meant being able to generate faster swim velocity. However, the swimmer with the highest force development on land was not the fastest in the water once fatigue set in. The swimmer that reached the highest swim velocity was the one that needed the least amount of force to increase speed, i.e. the swimmer with the more efficient swim technique


3) Yes and no. Improving strength on land that is relevant to the motions of swimming can lead to improved force development in the water, but of course the proper mechanics need to be used both on land and in the water to see this gain.

4) Yes there was a drop in force development as the stroke rate increased and the swimmer fatigued – seen both in Vasa SwimErg measurements and with the SmartPaddle measurements. This means the drop in force in the water is not only due to an increase in resistance; there is a fatigue component that can be trained and improved on land that can be carried over into swimming.

vasa power lap

To read the presentation of this study from World Aquatic Development Conference in Lund Sweden, January 2020 click below