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Introduction: Postural instability and the inability to regain balance are recognized as major contributors to falls and fall-related injuries in occupational environments. Roofers are required to spend more than 75% of total work time in awkward working postures, potentially negatively affecting one’s static and dynamic postural stability. Thus, identifying an individual’s potential fall risk due to awkward posture exposure may be critical in fall prevention in occupational environments. Purpose: Aim 1: To determine the impact of awkward working postures on obstacle negotiation strategies and postural control after returning to level surfaces. Aim 2: To assess changes in erector spinae muscle architecture when exposed to awkward working postures. Methods: Twenty-seven participants (24 males, 3 females) were recruited for this study. This study involved a pre-test/post-test assessment of balance, locomotion, and architectural changes to the erector spinae in response to a workload performed in stooped and kneeling postures. The workload involved 50 repetitions of simulated shingle installation on a 6’ x 6’ roof segment with a 6/12 pitch (26 degrees). The pre-test/post-test measurements included an ultrasound image of the lumbar erector spinae, static balance, and lower extremity gait kinematics during obstacle negotiations. Results: Manuscript 1: Greater maximum knee flexion and dorsiflexion angles were observed during UT and ET trials compared to NG trials after workload, but no significant differences were observed between groups. Individuals assigned stooped posture presented greater maximum plantarflexion angles of the trail leg after workload. Manuscript 2: No significant differences were observed in erector spinae pennation angle, peak force, or average force production. Manuscript 3: No significant decreases in postural stability were observed after workload in either posture during mCTSIB, LOS, or SLS tests. Discussion & Conclusions: Manuscript 1: Lower extremity gait kinematics were significantly impacted after workload. Manuscript 2: Workload did not result in fatigue-related changes in lumbar erector spinae structure and function. Manuscript 3: Static postural stability was not significantly influenced by workload. Importance: The findings from the current study provide insight into potential physiological and biomechanical effects of awkward working posture on individuals’ fall risk in occupational environments.