Specific Adaptation to Imposed Demands (or SAID) is a principle from exercise physiology. SAID basically says you get better at what you do—whether you do something intentionally or unintentionally, formally or informally. It also means you get better at the specific thing you do, not something else. There may be positive carryover, or there may be negative carryover, or there may be little-to-no carryover at all to other activities.
If you run long distances slowly, your body adapts, making you better at running long distances at that speed. If you sit in an office chair all day, your body adapts to that too, making you better at sitting in office chairs all day (and worse at other things, like running long distances).
SAID also implies that running long distances slowly is not a good way to become better at running short distances quickly, nor lifting heavy weights a few times. There may be some positive carryover to sprinting (but not much), and there may be negative carryover to lifting heavy weights a few times, but primarily if you run long distances you’ll get better at running long distances. (more…)
