Final answer:
The best breathing technique Clint can present for Julia to improve her lumbar stability is diaphragmatic breathing.
Step-by-step explanation:
The BEST breathing technique Clint can present to help Julia improve her lumbar stability is diaphragmatic breathing. Diaphragmatic breathing, also known as deep breathing, involves the contraction of the diaphragm. As the diaphragm relaxes, air passively leaves the lungs, helping to stabilize the lumbar area.