García-Pinillos, F, Laredo-Aguilera, JA, Muñoz-Jiménez, M, and Latorre-Román, PA. Effects of 12-week concurrent high-intensity interval strength and endurance training program on physical performance in healthy older people. J Strength Cond Res 33(5): 1445–1452, 2019—This study aimed to analyze the effect of 12-week low-volume high-intensity interval training (HIIT)-based concurrent training program on body composition, upper- and lower-body muscle strength, mobility, and balance in older adults, as well as to compare it with a low-moderate–intensity continuous training. Ninety active older adults were randomly assigned to experimental group (EG, n = 47) and control group (CG, n = 43). Body composition and physical functioning were assessed before (pretest) and after (posttest) a 12-week intervention. A 2-way repeated measures analysis of variance was used to test for an interaction between training program and groups. The time × group interaction revealed no significant between-group differences at pretest (p ≥ 0.05). The group × time interaction showed significant improvements for the EG in body composition parameters (p ≤ 0.05) and physical functioning (muscle strength: p < 0.001; mobility: p < 0.001; and balance: p ≤ 0.05); whereas the CG remained unchanged (p ≥ 0.05). This HIIT-based concurrent training program led to greater improvements in body composition, muscle strength, mobility, and balance in healthy older people than a regular low-moderate–intensity continuous training, despite the reduction in overall training volume.