The Royal Marines have devised a computer exercise programme to trim up flabby civilians. The programme, which is based on a marine's basic training course, can be adapted to take account of your age and fitness level. It is available on a CD-ROM. However, some experts fear the training regime is too extreme for the average person. Captain Phil May, of the Royal Marines, told the BBC: "You can spend an hour doing not really a lot in the gym and not getting a great deal of benefit unless you have got an instructor, or you know what you are doing. "This CD features instructors that are based here and we have worked out your programme, so you will get some benefit." The marine course is based on physical stamina exercise. Aimed at 17 to 35-year-olds, it sets what it describes as "ambitious" fitness targets. The marine basic training course lasts for 30 weeks, and the new recruits are closely supervised. However, recruits do regularly hurt themselves, and several have died in the last five years. Fitness experts are worried that the programme may be too dangerous, particularly as the exercise routine is unsupervised. Nick Webborn, of the Sports Medicine Institute, said: "This does not seem to be the thing that will encourage the coach potatoes to become active, and it would give me some concern if this was aimed at that population. "The technical difficulty of some of the exercises and the intensity would concern me because of the risk of injury." The marines say that if the programme proves too difficult then people should stop. The CD does contain regular warnings.