At a time when American adolescents are often disparaged as lazy and undisciplined, record numbers of them are signing up for a voluntary military training programme for students as young as 13.

“They’re craving discipline; they thrive on it,” said Army Lieutenant Colonel James Rose, who runs the Junior Reserve Officer Training Corps Program at Roosevelt High School in San Antonio, Texas. “And the first thing I teach them is to have pride in themselves, which the majority don’t have.”

The number of public secondary schools that offer JROTC programmes has grown by more than 60 per cent since 1992, from 1,481 to about 2,400. Enrolment grew from 200,000 to more than 300,000 during that same time.

“I didn’t think today’s youth would want the regimentation of ROTC, but I was wrong,” said Tom Witham, principal of Gloucester High School in Massachusetts, where JROTC began this autumn and there is a waiting list to get in. One out of seven students in the school signed up.

It was General Colin Powell, who, as chairman of the Joint Chiefs of Staff, urged restoring military programmes in the schools. General Powell, who credits his military career with helping to lift him from his own roots in the inner city, persuaded Congress to increase JROTC funding in 1992. The programme costs about $160 million (Pounds 100m) a year, or $500 (Pounds 300) per student.

Officer-instructors say students want to build their leadership skills, get some discipline and boost the starting pay they would receive if they decide to join the military. About half end up enlisting in the army, navy, air force or marines.

“They get a structure of what is expected, a chance to be responsible and to practise leadership and responsibility for others and to others, instead of just being in a classroom talking about it,” said Army Lieutenant Colonel Gary Banks, who runs the JROTC classes at Walla-Walla High School in Walla-Walla, Washington.

Cadets perform community service, spend weekends together in military training, establish their own chains of command, write directives and schedules and conduct inspections. They take classes in leadership, physical fitness and health, drills and ceremonies, marksmanship and military organisation. If later they join the military, their JROTC service lets them start two pay grades ahead of everybody else.

“It’s a great laboratory for actually practising the art of leadership, which we talk about so much,” Colonel Banks said.

The increasing presence of JROTC cadets also has an impact on their schools, according to teachers and administrators. Mr Witham, the principal in Gloucester, said he has never been called “sir” so much in his life.

“The kids are very recognisable in uniform and certain standards are expected of them,” Colonel Banks said. “We expect them to maintain that same sort of civility, not only in our class, but outside.”

Colonel Rose, whose school serves a low-income urban neighbourhood, said students behave differently as soon as they get out of their “ragtag clothes” and are issued a uniform. The oldest cadets lead classes for the youngest.

“It’s all about self-discipline and responsibility and how to respect people,” said Esther Nunez, 16, the highest-ranking student in Gloucester’s new JROTC unit. “We set an example for everybody else.”