Arthritis is one of the conditions that responds most consistently well to private Pilates. Movement is medicine for arthritic joints: it maintains the synovial fluid that lubricates them, strengthens the muscles that take load off them, and preserves the range of motion that arthritis progressively tries to remove. High-impact exercise and group classes can aggravate arthritis; private, low-impact, apparatus-based Pilates rarely does. The work moves around pain rather than through it, and adapts to where you are on any given day.