 Faced with a manpower shortage, French planners had to rely more on older and less fit reservists, who would take longer to mobilise and would diminish French industry because they would leave their jobs.Static defensive positions were therefore intended not only to buy time but to economise on men by defending an area with fewer and less mobile forces.In 1940, France deployed about twice as many men, 36 divisions (roughly one third of its force), for the defence of the Maginot Line in Alsace and Lorraine, whereas the opposing German Army Group C only contained 19 divisions, fewer than a seventh of the force committed in the Manstein Plan for the invasion of France.