This video covers Prone Shoulder External Rotation (ER) PAILs/RAILs - a drill designed to expand and strengthen shoulder ER so the range you gain is range you can actually control. Shoulder external rotation is a big piece of healthy overhead mechanics, stable pressing, strong pulling, and shoulder positioning under load. When ER is limited or weak, people often compensate with rib flare, lumbar extension, or scap dumping - especially during overhead work - so building ER capacity helps shoulders feel more stable, efficient, and resilient over time.

The sequence (repeatable for sets or reps):
1. Passive stretch (~2 minutes): settle into the prone ER setup and breathe, letting the tissues adapt while you refine alignment.
2. PAILs (progressive isometric contraction): gradually ramp tension into the position to create the intended stimulus for the day.
3. RAILs (regressive isometric contraction): reverse the intent and actively pull deeper into the newly available ER range with controlled effort.
4. Sink into the new range: ease off slightly and settle into the position you just earned.
5. Repeat for additional rounds if you’re doing multiple sets.

Programming note: The iso duration, intensity, and time under tension depend on the goal of the day - lighter/shorter for prep and patterning, heavier/longer for strength and adaptation.

Equipment: Yoga blocks - one to rest/support the elbow, and another to progress the position and increase the ER range as needed.