Jagim, AR, Rader, O, Jones, MT, and Oliver, JM. Physical demands of multimodal training competitions and their relationship to measures of performance. J Strength Cond Res 31(5): 1212–1220, 2017—The purpose of this study was to identify the physical demands of multimodal training (MMT) competitions and to determine the extent of their relationship to select measures of performance. Eighteen (>1.5 years of strength training experience) men (n = 10) and women (n = 8) (mean ± SD; age: 37.8 ± 10.6 years, height: 172.8 ± 8 cm, weight: 77.4 ± 13.2 kg, 16.6 ± 6% body fat) with experience performing MMT participated in a simulated MMT competition. All participants were assessed for body composition, countermovement vertical jump, and aerobic capacity during baseline testing. All participants then participated in a simulated MMT-style competition on a separate day within 10 days of baseline testing. The simulated MMT-style competition consisted of 3 events with 90 minutes of recovery allowed in between events. During the events, changes in blood lactate (La), heart rate (HR), and estimated V[Combining Dot Above]O2 were recorded. Bivariate (Pearson) correlations were computed to determine if a relationship existed between traditional measures of performance and those of the MMT-style competition. Significance was set at p ≤ 0.05. Mean change in La ranged between 9 and 12 mmol·L−1 during the events. Mean HR and estimated V[Combining Dot Above]O2 values ranged from 145 to 172 b·min−1 and 24 to 35 ml·kg−1·min−1, respectively, during the events. A strong correlation was observed (r = −0.722; p < 0.001) between aerobic capacity and time to completion for event 1. There was a strong correlation between lean body mass and lower-body strength performance (r = 0.882; p < 0.001) and time to completion for event 3 (r = −0.792; p < 0.001). A strong correlation was observed between lower-body power and time to completion for event 1 (r = −0.755; p < 0.001) and event 3 (r = −0.818; p < 0.001). Based on the results of this study, MMT-style competitions appear to be physically demanding activities performed at a high intensity with a great involvement of the anaerobic energy system and that some measures of aerobic capacity and power correlate with performance. When training for MMT-style competitions, it may be beneficial to focus on improving lower-body power and/or aerobic capacity.