Effects of a 7-week outdoor circuit training program on Swiss Army recruits

The purpose of this study was to implement an outdoor circuit training program as an addition to standard training and to examine its effects on physical fitness and injury incidence rate in Swiss Army recruits. An intervention group (standard and additional training, n = 134, 21.0 ± 1.1 years, 74.1 ± 10.0 kg, and 1.78 ± 0.1 m) and a control group (standard training only, n = 125, 20.4 ± 1.2 years, 73.3 ± 9.1 kg, and 1.78 ± 0.1 m) from the same fusilier infantry training school were compared. Physical standard training in the Swiss Army is specified to consist of 2 sessions with a total duration of at least 3 h·wk(-1). Groups of 20-50 recruits undergo these trainings in a gymnasium hall and outdoors. Standard training includes a wide range of exercises and sport activities (strength and aerobic fitness training, team sports, obstacle courses, physical fitness tests, and orienteering). The additional circuit fitness training program implemented in this study was conducted once a week for 60 minutes. It was performed outdoors and consisted of the same exercises every week (warm-up, squats, prone bridge, back and shoulder exercise, stair climbing, side bridge, single leg balance, walking on a balance beam, intermitted running, and active recovery). Volunteers' physical fitness was assessed during the first and last weeks of basic military training (7 weeks) using a standing long jump, seated 2-kg shot put, 1-leg standing test (OLS), trunk muscle strength test (TMS), and progressive endurance run (PER). Injury data were collected in medical records for the 21 weeks of military training school. The intervention group performed 1.0 session of standard training for 70.0 minutes and 1.0 session of additional outdoor circuit training for 50.0 min·wk(-1). The control group performed 1.3 sessions of standard training for a total of 70.7 min·wk(-1). After the 7-week basic military training, the intervention and the control groups showed significant improvements in OLS (35.63 and 9.79%), TMS (29.84 and 11.31%), PER (15.64 and 16.37%), and total physical fitness score (12.04 and 7.78%, p < 0.05). The intervention group showed significantly greater improvements in OLS, TMS, and total physical fitness score than did the control group (p < 0.05). No significant difference in injury incidence rate between the 2 study groups (intervention group: 14.2, control group: 13.9 injuries per month per 100 persons) was registered. The results indicate that the change from a civilian daily routine to the physically more demanding military routine led to significant improvements in physical fitness in both study groups. The additional outdoor circuit training session per week led to greater improvements in total physical fitness score but did not increase injury rates.