You are more tensed than you realize

Yesterday I went to the gym at my rowing club to exercise. I asked one of the club members to coach me, because I was not sure if my posture was right on the rowing machine. During the rowing I felt a tension coming up in my upper back. I have that often whilst rowing. So I wanted to fix it. Get rid of it, it's annoying. I tried to relax. Shake my shoulders. And really focus on steps of taking a good stroke. Shoulders low, straight core. The tension did not go away. I asked the coach: 'I have this back pain, how can I prevent it?' He said: 'Yes, I see you are very tensed in your shoulder muscles.' And I thought: 'But I try to relax so hard! How am I tensed in my shoulders?! That is exactly what I do not want!' I put way more tension in my shoulders then I realized. But it made so much sense for me to focus on the perfect posture to prevent my pain there. The coach said: 'Focus on the power in your legs and feet. Don't pull your arms. Let them come naturally towards you.' After that, I stopped trying to get the perfect stroke. I gave no attention to my shoulders and arms anymore. I putted the power in my legs. And my arms floated towards me. That made a huge difference. It felt way more relaxed and pain free. If you focus on the perfect solution to make your tension go away, your tension will grow. And then, you carry way more tension with you, then you realize. And that builds up to even more pain. All you need sometimes is a coach who points out that you are tensed. Who reflects on what you are doing. And guides you to a way where you can get sustainable power, that feels relaxed.