To treat lumbar stenosis with physical therapy, focus on gentle stretching and mobility exercises to relieve pressure on the spinal nerves. Strengthen the core, glutes, and lower back muscles with exercises like pelvic tilts, bridges, and modified planks to support the spine. Flexion-based exercises, such as knee-to-chest movements, can help reduce nerve compression. Incorporate low-impact aerobic activities like swimming or cycling to improve mobility and endurance. Gradually progress, avoiding positions that increase pain or discomfort.