Metabolic analysis of male servicemembers with transtibial amputations carrying military loads

For servicemembers who have sustained amputations and wish to return to Active Duty, performing common military tasks is essential. The purpose of this study was to examine the metabolic requirements of servicemembers with transtibial amputations wearing a loaded rucksack and walking at a steady speed. We tested 12 servicemembers with unilateral transtibial amputations and 12 uninjured controls on a treadmill at two walking speeds (1.34 and 1.52 m/s) while they carried a 32.7 kg load. Oxygen consumption was recorded. Results showed that metabolic demand for the injured servicemembers was significantly higher (8.5% at 1.34 m/s and 10.4% at 1.52 m/s) than for controls. An understanding of energy expended during load carriage by this study population is critical for decisions regarding return-to-duty requirements. Although significant differences existed between uninjured controls and those with amputations, it is important to note that those differences are less than previously published. This finding, coupled with the fact that servicemembers with transtibial amputations have redeployed, implies that, despite statistical significance, results may not be clinically relevant. Future work should include more taxing conditions to identify a threshold for potential limitations.