Cold exposure during military operations: effects on anaerobic performance

This study examined the effects of military field operations (MFO) under different environmental conditions on anaerobic performance. US Marines were tested in the field under the following conditions: 1) noncold environment (NC; n = 30, 10-32 degrees C) and 2) cold environment (CO; n = 32, -2 to -22 degrees C). Subjects performed 30-s Wingate tests (WIN) pre- and immediately post-MFO to assess anaerobic performance. The MFO consisted of approximately 4.5 days of combat training maneuvers while carrying field equipment (packs and weapon, approximately 25 kg). WIN measures obtained were absolute and relative mean power (MP), 5-s peak power (PP), and fatigue index (% decline). Significant main effects (P less than 0.01) were observed for time (pre-post MFO). Reductions occurred in absolute MP [651.8 +/- 30.3 to 616.4 +/- 28.5 (SE) W] and PP (897.8 +/- 41.6 to 857.0 +/- 39.1 W); however, no effect on fatigue index was seen. Significant interaction effects (P less than 0.05) were observed in relative measures. Reductions (pre-post) in MP (NC = 8.64 +/- 0.16 to 8.37 +/- 0.14 W/kg; CO = 8.91 +/- 0.26 to 8.04 +/- 0.15 W/kg) and PP (NC = 11.80 +/- 0.24 to 11.61 +/- 0.33 W/kg; CO = 12.23 +/- 0.35 to 11.20 +/- 0.19 W/kg) were greater under CO than NC conditions. These changes were found despite significant (P less than 0.05) but comparable pre-post weight reductions in both CO and NC conditions.(ABSTRACT TRUNCATED AT 250 WORDS)