Effects of Prolonged Combined Aerobic and Strength Training on Movement Velocities During a Strength Loading Bout: Targeting Same Versus Separate Muscle Groups

ABSTRACT: Feuerbacher, JF, Jacobs, MW, Dragutinovic, B, Rehbein, P, and Schumann, M. Effects of prolonged combined aerobic and strength training on movement velocities during a strength loading bout: targeting same versus separate muscle groups. J Strength Cond Res XX(X): 000-000, 2026-Combined aerobic and strength training may impair explosive strength performance, especially when targeting the same muscle groups. This study aimed to assess the effects of prolonged combined aerobic and strength training on movement velocities and velocity loss during a strength loading bout when the aerobic and strength training target the same vs. separate muscle groups. Thirty-two men participated in a 12-week intervention, divided into 3 groups: (a) LHLS (lower-body high-intensity interval training (HIIT) and strength training), (b) LHUS (lower-body HIIT and upper-body strength training), and (c) LSUS (lower- and upper-body strength training). Changes in the area under the mean propulsive velocity (MPV) and velocity-loss curves during strength loadings were analyzed pre- and postintervention. Squat performance was compared between LHLS and LSUS, while bench press performance was compared between LHUS and LSUS. The level of significance was set at ρ ≤ 0.05. During bench press loading, no statistically significant main effects for group (p = 0.225), for timepoint (p = 0.170), nor group × timepoint (p = 0.943) were observed for MPV. In squat loading, a statistically significant main effect for timepoint was found (p = 0.020), with a decrease in MPV for LHLS postintervention (p = 0.006). The interaction between group and timepoint was not statistically significant (p = 0.083). No statistically significant main effects for group (p = 0.110, p = 0.076), for timepoint (p = 0.590, p = 0.244), nor group × timepoint (p = 0.626, p = 0.239) were observed for velocity loss in either bench press or squat loading. These findings suggest that explosive strength performance may be more susceptible to interference when aerobic and strength training target the same, rather than different, muscle groups.