Biceps don't get much isolation time in functional fitness workouts but it's cool to show them some love. Nothing wrong with well-developed arms and they do look good, there's always that.
Lack of mobility can spell the difference between a miss and a big new PR.
What was final straw that made me turn my back on the king of strength exercises?
I know stretching your lumbar spine feels good. But you are actually making your pain worse.