...following an ETK-like program for a little less than a year now to boost my rowing performance.
Kettlebell Training For Rowing
Rowing movements are going produce that greatest effect for you Rowing.
"The Law of Specificity" applies: preform movement that are similar in nature to your sport and increase the Strength and Power of the muscle specifically involved.
Especially, ...
Heavy Kettlebell Swings
The majority of individual who preform Kettlebell Swing do not use enough weight with the movement to elicit an optimal training effect, increase Power and Strength.
Heavy Swings with a Kettlebell Swings with loads of more than half your body and right at your body weight need to be employed.
Since you weigh 170 lbs, that means the optimal loading would be at least 85 to 170 lbs are necessary.
Are Heavy Kettlebell Swings Better Than Deadlifts? | T Nation
Research by Dr Bret Contreras found that Heavy Kettlebell Swing produce the greatest Power Output.
Some of the highest Power Outputs measured, if not the most, are produced with Olympic Movements.
Contreras found Heavy Kettlebell Swing rival Power Output and Power Development.
Lighter Kettlebell Swings do not do this.
Reasons WhyIndividual Perform Light Kettlebell Swings
1) Lack of knowledge: The majority of individual are unaware of the Power Output produced and developed with Heavy Kettlebell Swings.
2) Kettlebell Price: Heavy Kettlebells tend to be expensive.
A Cheap Alternative
...is a Home Made Hungarian Core Blaster. The cost to make it is about $20 with pipe you purchase at Lows or Home Depot plus some Standard Weight Plates. You an purchased Used Standard Weight Plates on Craigslist for about 55 cent per pound.
I have and use the Hungarian Core Blaster for Kettlebell Swings. It work great.
I've loaded mine up to 170 lbs.
The only downside is that it is "One Trick Pony"; the Hungarian Core Blaster can only be used for Kettlebell Swings or Kettlebell Deadlifts.
Contreras article above provides information on how to make your own Home Made Core Blaster.
...a point where the offset torque starts to wear on tendons and joints.
Quite the contrary. Strength Training of this nature (any Strength Training Program) increases tendon and ligament strength and size.
This information is well documented and easy to find via Google.
Muscle grow in strength and size occurs quickly, followed by growth of tendons and ligaments.
Chronic Over Use And Abuse
What wears down tendons, ligaments and joint is Chronic Over Use and Abuse.
Kenny Croxdale