Elbow pain and mountain biking

I’ve been getting back into mountain biking over the last month. I haven’t mountain biked in probably 8 years or so, but have consistently road / tri biked.

Is there any obvious reason as to why my elbows are super sore after only 1-2 hours of mt.biking? I’m not going crazy on the trails or doing anything intense, but my elbow’s are consistently sore…is this just bad fitting on my bike? Or my bodies way of saying, hello new muscles that usually aren’t used…?

Are your elbows locked a lot while riding?

It’s hard to do at first but keep them bent a little for shock absorption.

jaretj