An ergonomic assessment was conducted to quantify the activities and physical demands during the British Army’s 8-week Platoon Sergeant and Section Commander Battle Courses (PSBC, SCBC). Twenty PSBC and 18 SCBC male infantry soldiers volunteered. Body Mass (BM) was measured pre- and post-course, with course physical activity levels (PAL), energy expenditure (EE) and sleep profiles quantified using tri-axial accelerometery. The courses were predominately field-based, involving slow and rapid load carriage tasks, digging and moving casualties. Average daily EE (SCBC = 4020 ± 599 vs. PSBC = 3876 ± 525 kcal.day−1; p>0.05) and BM decreases were similar (SCBC = −3.9 ± 2.9 vs. PSBC = −2.0 ± 2.7 kg; p>0.05). Daily PAL was higher for SCBC than PSBC (2.1 ± 0.3 vs. 2.0 ± 0.3, p=0.041), likely due to greater moderate-vigorous activity levels (p=0.003). Daily sleep durations were variable, but similar across courses (≈5.1 hr.day−1; p>0.05). These data confirm these courses are arduous and can be used to inform course-specific physical screening tests and training to increase course success.