Basic Leg Mechanics – Stroke Cycle
Since 2009 we have tested 2000+ athletes with our instrumented foot stretcher and consulting protocols. We always have a lens focused on lower limb mechanics and how they effect the entire rowing movement. Why? Because the legs and feet create the first contact point to the boat and produce the highest force you will see in the boat. In many of these analysis protocols we study the time and percentage of the stroke cycle in which key points, or segments, of the leg mechanics occur.
This approach and the data we collect provides a framework for a number of future investigations, and this work still forms the basis of many of our areas of research into rowing performance and injury prevention. The current sample shows data found on the Concept2 erg across approximately 150 rowers of various levels from school-college/sub-elite.
Across all the athletes and rates observed, the legs were “active” on average for approximately 79% of the drive phase of the rowing stroke. Hence our obsession with prioritising it as a way of finding more boat speed.
To give you a snapshot of how to think about what your stroke cycle is made up of, here is an example breakdown of what we found at a rating 20 strokes per minute:
Total stroke cycle: 3 seconds
Drive time 1.08 seconds
Recovery 1.92 seconds
Leg drive time 0.80 seconds
Time from catch to peak force: Approx 0.55 seconds
Time until initial heel contact 0.60 seconds
The research directions for our team are many and varied, and have led towards a multi-disciplinary approach to improving performance. For example, when looking at the timing of these mechanical milestones compared to the mechanics of a vertical lift off the ground (e.g. deadlift or clean as spoken about in our last post), the rowing leg mechanics seem at odds with what current trends for good gym technique dictate. How then could we change our strength and conditioning to cater more specifically to rowing? Or what can we learn from the key support/load structures in biomechanics to enhance our stroke?
From the example above we can see that the legs are active for 74% of the drive time, but only 18%
of the leg drive occurs after the heel is down and in these cases the heel connection has occurred just after peak force is reached. We know that the foot is most stable with more surface area on the footboard, and that there is a strong correlation between the greatest foot surface area and peak force – across the board these rowers are missing the ability to load most effectively.
We also know that the human body is best protected by having a stable platform against which to push against. This has led us down a number of paths in relation to technique, equipment and athlete set-up.
We also look at the increasing joint force on the ankle during the late recovery and its role in the resistance we feel into the catch. These basic mechanics may predispose an athlete to rush into the catch or compensate with a body movement to overcome this resistance, so what can we change about how the foot is set up to minimise this resistance? One of the easiest facts is an earlier heel connection most importantly, load, as well as giving a more connected platform at the finish of the stroke.
Before making any changes to what we do, we need to understand the mechanics, in detail, of what we are
currently doing. Becoming more mindful of how we use our legs and feet in rowing is a step towards a faster boat. Next time your are in the boat, have a think/feel/look at what your legs are doing and visit our site; www.batlogic.net to learn more and find extra speed!