A marathon running event is a long-distance foot race over a distance of 42.195 kilometres or 26.219 miles. Marathons are a popular form of recreational and competitive running with more than 1000 marathons being held throughout the world each year. Most people start running to improve their fitness or to lose weight, but then find it a fun and stress-relieving activity. It is a very good way of improving cardiovascular fitness. Setting a marathon goal helps runners to stay motivated whilst improving health and fitness. Many say running is the easiest sport to fit into a busy lifestyle because it is free and can be done anywhere and at any time. 
History
Legend has it that the origins of the marathon date back to 490 BC. A Greek messenger soldier ran from Marathon to Athens with news of an important Greek battlefield victory. It is said he collapsed and died after delivering the message. This is thought to be the inspration behind the modern endurance race and how the running event got its name. The first official marathon was held in 1896 with the distance set at 40 kilometres (nearly 25 miles) which was the original distance between Marathon and Athens. In 1908 the race distance was changed to 42.195 kilometres. This was allegedly to accomodate a royal request for the race to start on the lawn of Windsor Castle and to end in front of the royal box at the London stadium.
Statistics
Approximately 1.1 million runners complete a marathon each year which is about 0.01% of the world's population. Only about 30% of global marathon runners are women and the average marathon runner is 40 years old. Men are traditionally faster than women but in recent years the finishing time for men has slowed down whilst women have been improving. As would be expected runners over the age of 70 have the slowest finish times with those aged 30 to 50 being the fastest. The fastest male world marathon time is recorded at 02:01:09 and for women is 02:14:04.
Running Injuries
Injuries are common with at least 45% of regular runners getting injured each year. The most common injury amongst runners occurs in the knees with the hips, legs and ankles also at risk. Women have a higher injury rate than men. Risk factors include lack of running experience, previous injuries, a higher body mass index and undertraining. To avoid injury marathon runners need to run 40 miles per week to reach and maintain peak fitness.
Arthritis and tendonitis are chronic diseases which are not caused by a single injury. They develop slowly over time and are probably the most debilitating of all marathon running injuries. They can be repaired and prevented by the right type of fitness and strength training. 
Age Graded Results
Fitness and performance decline with age. We all naturally slow down as we get older which can be demotivating for runners. Age graded results help senior runners to compete on a level playing field with younger generations. Finishing times are converted into a percentage which gives a fair comparison between athletes of different ages and genders. The best recorded performance time for each age, distance and gender is used to provide a graded result. This performance time is divided by the finishing time of the runner to give an age graded percentage. As an example, a 50-year-old female completes a marathon in 03:36:24. The best time for this age, gender and distance is 02:33:57 which is divided by the finish time to give an age graded performance of 71.14%. Club runners aim to hit 80% but any score above 70% is a good standard. This table provides guidance on the standard achieved:
Age Graded	Percentage	Rating	Level	
	Above 100%	A	New record performance	
	100%	B	World record class	
	Above 90%	C	World class	
	Above 80%	D	National class	
	Above 70%	E	Regional class	
	Above 60%	F	Local class	
It can be more motivating to focus on an age graded result rather than a running speed. In many running events the age graded champion earns as much recognition as the winner of the event. It also enables runners to track their performance over time, set goals and even identify their best performance.
People new to marathon running should follow a recognised training plan at least six months before their first event. It is recommended to run three to five times a week. Runners should aim to increase their distance by 10% each week until they are running 50 miles per week. Rest days are also important and should be incorporated to let the muscles recover. Competing in a few shorter race distances is an ideal way to prepare both physically and mentally for a first marathon. Good running shoes and nutrition also play an important part in training. Excellent information and guidance can be found on the Internet.