Final answer:
The activity that would be most impaired at altitude is the 10 km run, due to decreased oxygen levels at higher altitude affecting endurance activities.
Step-by-step explanation:
Based on the information provided, the activity that would be most impaired at altitude is the 10 km run.
Altitude affects performance in endurance activities due to lower oxygen levels. As altitude increases, the air becomes thinner and has lower oxygen content. This leads to decreased aerobic capacity, making it harder for the body to supply oxygen to the muscles during prolonged activity.
The 10 km run is a long-distance endurance activity that heavily relies on aerobic energy production. Therefore, it would be more impaired at altitude compared to shorter and more anaerobic activities like the 100 m sprint, 300 hurdles, and shot put.