The Great South Run is Britain's biggest 10 mile (16 kilometre) road race
The Great South Run attracts celebrities, sports stars and thousands of club runners and fundraisers - all keen to battle the flat and fast 10-mile circuit.
The event is Britain's biggest 10-mile (16km) road race and passes many of the city's most famous landmarks
Millions of pounds are raised for good causes each year.
Before the race, some of those taking part explained their motivation and reasons for running.
Angela (left) with running partner Erica
Name: Angela Clark
From: Newport, Isle of Wight
Before: I'm doing the Great South Run as I was successfully treated for bowel cancer last year and want to say thank you in my small way for all the fantastic care I received.
My Grandpa died of prostate cancer and my friend, who I'm running with, lost her dad to pancreatic cancer too.
I've never run it before (actually, I've never run 10 miles before). Training has been a little sporadic as I work and have three young children, but I'm confident I shall complete it.
I'm running with my friend, Erica Holyome. We work together - she is the headteacher and I'm the bursar of Newchurch Primary School. Poor Erica has broken her arm so will be running in a cast.
I'm looking forward to finishing it and feeling proud of myself for having completed such a challenge. I hope my children will be proud of me too.
Angela with her dad and children after the race
I enjoyed the run, particularly the atmosphere of the crowd cheering for everyone as they ran past. I did it in two hours which is what I was hoping for so I was pleased - although a bit sore the next day!
My children made some fab banners to cheer me on which was great
The last couple of miles where you were running into the wind was pretty tough though. The best bit was definitely turning the last corner and seeing the finish line - it was such a relief and I felt really pleased with myself.
My family were an amazing support to me on the day and I was so grateful for them being there to cheer me on!
Simon Ware has been given the 'Number 500' vest
Name: Simon Ware
Before: This is my 20th Great South Run and I'll be wearing Number 500 - to celebrate the 500th anniversary of the Mary Rose.
It does get slightly harder each year - you are another year older, but the training runs are going well and I'm hoping for a decent time - under 70 minutes. Sixty four minutes is my previous best.
I do it for a different charity each year, this time I'm running for the Alzheimer's Society.
It's great how the race has grown over the 20 years with lots of elite runners and the support along the way is great. I always get heckled when I run through the dockyard and past the Mary Rose museum where I work.
For first-timers I'd say take it easy, don't go off too quickly. We've had some soakings in the past few years, hopefully there'll be no wind and calm conditions.
Simon makes a flying start to his 20th Great South Run
After: The race went well - I ran 1hour 12mins, which was slightly down on last year's time. But I wasn't too disappointed, as the last two miles was very tough with a strong headwind along the seafront.
There was a great atmosphere with huge crowds supporting the runners throughout course. I had a nice special announcement over the PA system just before the race started, for my 20 year's of running the race, which was great. And then an invite into the VIP area for a post race meal, where I met a whole host of celebrities - some of which recognised me as the runner that had run every Great South Run - a super day!!
James Clark with his daughter Poppy
Name: James Clark
Before: Our daughter Poppy contracted meningitis in February of this year leading her to be isolated in hospital for six days and put on antibiotics. It hit us like a tonne of bricks - we didn't know what was happening but we are so thankful that Poppy was one of the lucky ones to survive.
I've done the Great South Run for the last four years but this time I wanted to give something back to the Meningitis Research Foundation who do such amazing work.
I run regularly and play squash, so I'm hoping to do it in one hour and 15 minutes. The first few miles are the worst until you get a sweat up but then my knee will go at the six-mile mark!
There is always a brilliant atmosphere, it's all you need to keep going - you don't need much motivation. I'll just keep going for my little girl, and thinking what could have been.
After: I wanted to raise money for a cause which will help prevent others from going through the terrible time our family endured. Poppy's illness was a devastating time for us, and thinking about her really kept me going during the run.
I'm pleased to have set a personal best time on my fourth GSR, and I'd like to thank everyone who sponsored me and helped me raise over £800 for MRF."
Chris Whittle - hoping his physio-knowledge will give him an advantage
Name: Chris Whittle
Before: I'm a final year physiotherapy student at Southampton University. I've been doing a lot of fitness work and going to the gym, but I needed an "end goal" to it all, and a friend - and another physio student, Helen Bowran - suggested doing the Great South Run.
My ankle has been bad in training but I'm hoping it will be ok as the course is flat - I've been running up and down the Avenue in Southampton in training.
This is my first long public race so it could be a bit of a test. From a physio point of view, I'd say start training early, gradually stepping it up, and have rest days.
On the day itself, get loaded with carbs on the Friday and Saturday and drink plenty of fluids.
I'm just going to enjoy the day - we're in the last group to go out so I'm not worried about the time, I just want to enjoy the atmosphere.
Chris and fellow runners Helen Bowran and Rececca Ward have a podium finish!
After: Your eyes are not deceiving you, that is the three of us on the winners' podium; it was more hijacked rather than us being up there legitimately though I'm afraid!
Well, injuries held up and we all made it around the course; an essential lavatory pit-stop and a disagreement with the sports drink were not to be the undoing of Helen and Rebecca (in no particular order)!
We all had a great day, the atmosphere was fantastic and everyone was so friendly. I was amazed to see how many different charities people were running for and how many good causes would benefit.
I'd been warned of the notorious last two miles into the wind and certainly wasn't disappointed; at times it felt like I was going backwards rather than making any progress! I'm delighted with my time and position and will certainly be back next year to give it another go!
The John family - look out for Victoria dressed as a bee
Name: Victoria John
This is the first time I have done the Great South Run. Both of my children are doing the junior run (they are 10 and 12 years old). My elder son Samuel was diagnosed with an inoperable brain tumour when he was nine-years old.
He was treated with chemo for two years and the tumour hasn't grown over the last six months. There is a 50% chance that he will need more treatment within the next 18 months, but we are just making the most of having a 12-year-old with hair for now!
We are quite an active family and both my boys played rugby and did karate - Sam has obviously been told no more contact sports, so now he tries to keep fit in other ways, running being one of them.
All three of us are running for CLIC Sargent because of the fantastic support that they have given us over the past four years. They have given Sam counselling and Matthew (his younger brother) goes to regular siblings' groups to talk and play.
They have given us days out as a family and taken the boys out alone too. I know that, if we should need it, we can ask them for financial support too. CLIC do so much for families who have a child suffering with cancer - the only way I can think of thanking them is by raising money.
The training was going very well until about a month ago when I caught a nasty cold and couldn't train for a few weeks. I have been trying to build up the miles again but have had to stop at six miles so that I don't damage myself before Sunday!
I was aiming for about a 90-minute run, I think it will be much slower now. I will be running with a friend who will be dressed as a ladybird (I will be a bee!). I am not very keen on running, but I don't feel that I could ask people to sponsor me for doing something that I enjoy!
Laura Fredericks is hoping to run the London Marathon
Name: Laura Fredericks
Before: I am doing the Great South Run as part of a personal goal to increase my fitness levels. I hope to take part in the London marathon within the next couple of years and I thought the race would help motivate me to train and get used to longer distance running.
In addition to this I felt it would be a great opportunity to raise money for the British Lung Foundation which provides support to those with all types of lung disease in the UK.
As I have never run anywhere near 10 miles before, I started my training early to allow time to increase my strength. Overall my training has been a success, however there were a number of occasions where I came home from a hard run and wondered why I had set myself this challenge.
I am pleased that I have been dedicated to my training as I have come a long way since the first few weeks when I struggled to run three miles without walking, and I am now able to run 10 miles in a respectable time.
I am most looking forward to being part of the atmosphere on the day and feeling a real sense of achievement when reaching the finish line. Not only will I feel proud to have completed the course, but I will also feel proud to have raised money for a worthy cause.
I am least looking forward to waiting on the start line and having achy legs the next day!
After: I really enjoyed taking part in the Great South Run 2009, I was surprised by the huge amount of support that was provided and found that the crowds really helped to spur me on towards the finish line!
The atmosphere on the day was fantastic and I felt a real buzz to be taking part in such a great event. I was really pleased to complete the whole race without walking and finish in a time of 1 hour 40 minutes, I already have plans to participate in the 2010 event and am aiming to break the 1 hour 30 mark.
The sense of achievement I got when crossing the finish line definitely made all the hours of training well worthwhile.