Most adults with transtibial amputation due to trauma (TTAT) are work-eligible yet are disproportionately unemployed. Inappropriate residuum muscle activity and load at the distal residuum-prosthetic socket interface (RSI) during prosthetic use are suggested contributors to employment-ending injury. The purposes of this study were to examine residuum muscle activity and RSI loads during self-paced gait, brisk gait, and carrying and to determine lift/carry capacities in 10 men with TTAT and 31 controls. A cross-sectional study design was used. Descriptive and bone health biomarker data were collected. During self-paced and brisk 2-minute walk tests, distances, step-length difference, and muscle activity (rectus femoris, tibialis anterior, gastrocnemius) were recorded. In participants with TTAT, RSI loads were simultaneously determined. Floor-to-knuckle lift and 25-ft carry capacity tests were conducted. Participants were similar in personal characteristics, biomarker values, self-paced/brisk walking step length differences, and distances walked. One participant with conventional TTAT and nine with osteomyoplastic TTAT demonstrated lower carrying (25.0 kg, p < 0.01) and lifting (28.0 kg, p < 0.05) capacities than controls did. In participants with TTAT, (1) all muscles tested were active during initial and terminal stance, (2) gastrocnemius activation was inverse to respective activation in intact/control limbs during self-paced and brisk walking, and (3) RSI loads were greater throughout self-paced and brisk gait. Authors caution that generalizations cannot be made because of sample size. Men with TTAT walked similarly in step length and distance but demonstrated lower lift and carry capacities than controls did. Future study may be warranted concerning rehabilitation strategies as well as muscle activation and RSI loading during gait based on surgical approach in men with TTAT.