Lat strain

About six weeks ago I made some changes to my paddle stroke, attempting to use less arm and more rotation power from my back and abs.  It seems to be working for me except for one thing – I continually strain my back primarily right under my shoulder blades (latissimus dorsi?).  I don’t tend to have a problem if I don’t push too hard but I tend to get carried away when someone else is on the water and I get competitive-this is all flat water paddling.  I believe the strain comes from the first part of my paddle stroke where I am putting downward pressure on the paddle.  I know that my back muscles are weak to begin with but I thought that after six weeks or so things would be
getting better.  Any thoughts about experiencing pain in this region?  

Thanks!

I am going through a similar transition now and on occasion get soreness like you do. It is minor and goes away easily which I attribute to my weight training and reverse rows in particular.
I think the main issue is like you said, muscle is probably out of tone. This is not something usually loaded in day-to-day activities.
If the soreness has set in and does not go away you probably need to help it with massage. However, since you say your upper back is out of shape, there's a chance that it's a soft tissue injury (hope not). Best to see a physio therapist. They will give you a massage routine to help the muscle recover. Long term solution is most likely resistance training which they will also guide you with. 

Thanks SpaceSputnik, 
It's helpful knowing other people have experienced this.  I just scheduled a massage for tomorrow.  The last time this flared up about two-weeks ago a massage helped a lot.  Enough so that I could go out and strain it again.  I had her spend an hour just on this area.  I'm done with going full-out now and will restrain myself until I can work these muscles out in a more controlled fashion in the gym.

Most welcome. Pretty normal for this sort of thing to happen unless you are 16. Not a measure of our resilience, just that various muscles get detrained more and more with age which leads to festering injuries. The problem with specific activities like paddling is that they cannot be tailored to keep the entire body equally trained unlike gym workouts. 

Due to shoulder issues I get  lot of back strain as muscles take over the role of other muscles.

What has really worked for me is to invest in a Lacrosse ball or field hockey ball. Lie flat on your back and then put the ball on the floor between the floor and your back. You can then use the ball to massage the muscles. Where it really shines is to break up the small muscle knots called trigger points that lead to a lot of pain and create imbalances.

After a long paddle I will spend a good few minutes just relieving the knots and working the sliding surfaces. It hurts but it hurts so good. 

I am used to it now but in the beginning either start with a tennis ball or start slowly. You can also use the ball under the feet, on your butt muscle, calves and the hamstrings all of which seem to get a little tight from paddling.

M

Rolling is a great way to heal muscle injury, but I believe ultimately stretching and strengthening is what keeps the injuries from occurring.

An inexpensive way to massage sore joints is the grid foam roller from Trigger Point Performance.  I have been using one for years and it's been bullet proof.