"Working" My Core with the EmPower Oarlock

June 28, 2017 Emma Overton Comments

By Alix James

I've been working through the real-time measurements available with my EmPower Oarlock connected to my SpeedCoach GPS – exploring the relationships between my rowing stroke and what the numbers on the screen are telling me. I'm lucky enough to row with a coach on a somewhat regular basis as part of Vesper Boat Club's master's program, so I have a very good idea of the many, many ways I need to improve. It has been really interesting seeing what values give me feedback that seems to match up to good rowing.

Many people think the primary value of the EmPower Oarlock will be the "Power" measurement, as in "How hard am I pulling?" Although knowing your power output in real time is helpful for metering effort in practice, and for avoiding a "fly and die" scenario in races, it's not a great feedback tool for stroke efficiency, since you can always increase the power by raising the stroke rate or "hammering on it", but neither of these yield the kind of improved stroke mechanics that get you through a head race, 2k, or even 1k.

"Work" on the other hand is your force over the length of the stroke. For those of you who remember your geometry, and have played with the power curve on the ergometer, Work is the area under the curve you build each stroke. The most effective way to increase the area under the curve is to make the tall part of the curve wider, and this takes a long and effective connection of your drive to the blade(s) in the water.

Rowing coaches have about one million ways to try to put this into words: "Stay long on the legs." "Be patient with the arms." "Take the handle with you when you drive." "Hang onto the finish." "Horizontal drive." "Connect your core to the blade." These technical recommendations all point to increasing the amount of time that maximum power is applied during the drive.

Time for some low rate steady state in my single with my EmPower Oarlock running and Work and Wash* selected in the bottom two windows. I quickly discovered that the difference between a good, connected stroke and a yucky one was big – over 50 Joules – so it was easy to see when I was stringing good strokes together. I started to play my "coaches' sayings" over in my head, and discovered that "connect your core to the blade" was the one that really made the biggest difference consistently.

When I sagged in my middle (a long-time habit), the Work value plummeted. When I kept my core strong and upright through the second half of the stroke, my Work value stayed up and my Wash value dropped. Success! Three miles later my middle was tired but I was rowing much better than when I launched … and all without an actual coach riding alongside me.

*In sculling, wash is the amount of drive arc, in degrees, that the oar travels after the force on the blade drops below 100N. For scullers, the default setting on the Oarlock is to double the measured work to show the effective work over both blades.

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Emma Overton