Reading gives me tennis elbow

I normally read books on my phone but our trip to the British Library gave me a hankering for a physical book. I now regret this.

I have been enjoying the Three Body Problem trilogy so much, and the final book has gripped me so hard, that I've done over half of it in three days (the previous book took me just over a month), and have aggravated my old tennis elbow injury. I'd assumed it was because I played a tonne of badminton last week, but I was fine this morning, then after reading a little at lunch my arm hurt so badly I've had to put the stupid book down.

Unrelated but I hope this deskmat lasts forever because I love it.