Freebase(0.00 / 0 votes)Rate this definition: In a parliamentary or semi-presidential system of government, a reserve power is a power that may be exercised by the head of state without the approval of another branch of the government.
5k race = 3.1 miles. Most beginner runners will take an average time to finish a 5k race of 30 - 40 minutes. 10k race = 6.2 miles. The typical time it takes to do a 10k race is 1 - 1 1/2 hours. Half marathon = 13.1 miles, 21.7 kilometres. A respectable time it takes to do a half marathon is 2 - 2 1/2 hours. Marathon = 26.2 miles, 41.2 kilometres. The average time it takes runners to do a marathon is between 4 - 5 hours.
A half marathon is 13.1 miles or 21 kilometers, or exactly half the distance of a marathon (26.2 miles). It's a good goal for runners who have already completed a 5K (3.1 miles) or a 10K (6.2) miles and are looking for a new challenge.