The Navy SEAL Physical Fitness Guide - Uniformed Services ...

" Physiological and environmental factors." Optimizing load-bearing." Physical training for load-bearing." Common medical conditions.Physiological andEnvironmental FactorsBody and Load WeightIdeally, it is best to select the load-bearing weight as a function of body weightrather than selecting an absolute load-weight per man. You may not have the flexibility totailor the load weight per man due to mission requirements. Therefore, an upper weightlimit for load-bearing should be calculated so the load will not create a higher physicaldemand (energy cost) for individuals with smaller stature and lower lean body weight.Determining the maximum weight of the load is a more important factor affectingload-bearing than the type of load carriage design. Numerous studies have examined theoptimal load-bearing weight you should maximally carry before there is a disproportionalincrease in the rate of energy expenditure. This is calculated as a percentage of bodyweight. Although those who are physically fit according to Physical Fitness Test Scores cantypically carry 45% of their body weight for 8 hours at a pace of 4 mph, a lighter load isconsidered optimal.“Rule of Thumb”: A maximal load should be 40% of bodyweight. Example: 40% of 170 lbs. is 68 lbs.The energy cost of the task rises steeply beyond this percentage. It has been reportedthat the energy cost of humping with a load increases proportionally with the weightcarried. For loads more than 40% of body weight, the energy expenditure risesdisproportionately and fatigue occurs sooner. The key is to carry your load as closeas possible to your body’s center of gravity. This will result in the lowest energycost when you carry a load, which is evenly distributed, on your back.176 Load-Bearing