Three hundred fifty male recruits were randomly allocated to either the standard recruit training program (N = 180) or substituted a weighted-march activity for all formal run periods (N = 170) in the physical training program. All injuries were seen at a single medical facility, and the cause, location, and severity of injury were recorded in the medical documents. Lower-limb injuries constituted 79.8% of all Run injuries and 61.1% of all Walk injuries. Foot (18.9%), knee (16.7%), ankle (13.3%), and shoulder (8.9%) were the most common sites of injury in the Walk group. In the Run group, the most common sites were knee (32.1%), ankle (18.3%), foot (11.9%), and shin (7.3%). There were two stress fractures (tibial) in the Run group and none in the Walk group, giving the Run group an incidence of 1.1%. There were 10 medical discharges in the Walk group and 16 in the Run group. Ten (62.5%) of the Run and 2 (20%) of the Walk discharges were due to lower-limb causes. Of these, only 1 (10%) of the Walk and 4 (25%) of the Run injuries were not considered to be pre-existing conditions. Marching (30.0%), physical training (25.5%), and the obstacle course (11.1%) were the most frequent causes of injury in the Walk group. In the Run group, the leading causes were running (36.6%), physical training (19.2%), and the obstacle course (14.6%). Running was the major cause of knee injury in the Run group (17/35), whereas physical training was the major cause of knee injury in the Walk group (5/15). Running was also the major cause of other lower-limb injuries in the Run group (19/58), whereas marching was the major cause in the Walk group (19/50). Lower-limb injuries were more frequent in the Run group, with running cited as the major cause of these injuries.