Army National Guard Maj. Deidre Musgrave says reserve cadets from around the country were at the Joint Forces Training Center for a two-week training stint.
She says all were responsive and stable after the lightning hit about 2 p.m. on Wednesday.
Camp Shelby near Hattiesburg is the nation's largest state-owned military training center. Its 136,000 acres cut out of southern Mississippi's rolling hills and pine forests includes mock cities designed to look like Iraq and Afghanistan to give soldiers realistic training.
Soldiers and airmen from around the country train there each year.