Does Loaded Marching Economy Explain Some of the Variance in Loaded Marching Performance?: 1199: Board #5 May 31 1:00 PM - 3:00 PM

Previous attempts have been made to identify physical and physiological variables that predict Loaded Marching Performance (LMP) (Williams and Rayson, 2006, Mil Med, 171, 1-7). However, the contribution of specific, sub-maximal measures such as LM Economy (LME) remains unexplored.

PURPOSE: To develop a model to predict 2.4-km LMP from selected physical and physiological variables.

METHODS: Forty-three (n=43) male infantry recruits, age (mean ± SD) 19.1 ± 2.1 years, stature 174.9 ± 5.8 cm, mass 69 ± 8.5 kg were physically assessed during weeks 1 and 2 of a 24-week British Army infantry training course. During week-1 recruits underwent a battery of physical tests that consisted of: anthropometry (height, mass, muscle girths and 8-site skinfolds); strength (dynamic and isometric); treadmill LME (steady state VO2 while carrying 25 kg, at 6.5 km-h-1 for 8-minutes), maximal incremental running (VO2max) and the Personal Fitness Test (PFT: 2.4-km run, 2-min press-ups, 2-min sit-ups). During week-2 a ‘best effort’ 2.4-km LMP test (with 20 kg) was conducted. Significant relationships (P<0.05), between LMP and the independent physical and physiological variables were assessed using Pearson's product moment correlation. A maximum of 3 variables were entered into the multiple regression analysis at any one time.

RESULTS: Data are presented as mean ± SD. LMP ranged from 12:49 to 18:11 min:s (15:29 ± 1:19 min:s). LME (ml·kg-l·min-1) (R = 0.65, P<0.01), peak static lift strength (kg) (R = −0.48, P<0.05) and 2.4-km run time (s) (R = 0.42, P<0.05) individually correlated with the 2.4-km LMP. Collectively they produced the best regression model (Equation 1), which explained 60% of the variance in LMP (R = 0.78, R2 = 0.60, SEE = 53 s, P<0.01). 2.4-km LM time (s) = (12.15 * LME) - (0.97 * Peak SLS) + (0.67 * 2.4-km Run Time) + 212.94 (Eq. 1)

CONCLUSION: The task specific measure of LME produced the strongest independent relationship with LMP and, when used in combination with other field performance tests, explained 60% of the variance in LMP. Future studies should determine the extent with which LME improves during recruit training and its subsequent influence on LMP.