Sometimes the smallest change makes the biggest difference.
Not sure how it happened but I noticed that the bar tape where my hands naturally sit on the curve round to the brake levers was getting mangled. I thought at first it was just normal wear, but then a moment of clarity struck and I decided to check the angle of the bars.
Sure enough, they were sloping downwards too much. Maybe it had happened over time or perhaps they hadn't been positioned correctly when the bike was put together after the last trip. Either way, it was all wrong, like having an ironing board that is sloping away from you.
Now that the bars are level I'm aware of how much pressure I was putting through my hands, wrists, arms and shoulders trying to keep hold. On the bike, you want to be as comfortable and efficient as possible but just this little thing being off was pulling me too far forward and making riding much harder.
Now that I've sorted it the difference is as plain as day. My arms are more relaxed, the shoulders are looser and a lot of the stiffness in my upper back has eased off.
Even better, I think my bar tape is going to last a lot longer!