Answer:
Running up a flight of stairs is different than walking because it requires a different type of muscle activity. When walking, the muscles in your legs move in a more controlled and rhythmic manner, allowing you to maintain a steady pace and avoid stumbling. In contrast, running up stairs requires your muscles to work in a more explosive and powerful manner, generating bursts of force to push you upward and forward. This type of muscle activity is much more intense and demanding, and it requires more energy and effort than walking.
Additionally, running up stairs also requires you to overcome the force of gravity to a greater extent than walking. When you walk up stairs, you are able to use the stairs to support your weight and to assist you in moving upward. When running, however, you are moving too quickly to use the stairs in this way, and you must rely on your own muscle power to lift your body upward. This additional force of gravity makes running up stairs more challenging and demanding than walking.