In this study, untrained men performed resistance training either alone or followed by post-exercise cardio. Training was self-selected based on whether participants prioritized fat loss or muscle gain. After 14–16 weeks, the post-exercise cardio group lost more body fat, while strength gains were similar between groups. So do you need cardio for fat loss? Let’s take a closer look.

Overview

What did they test? Twenty-seven untrained men completed 14–16 weeks of resistance training, either alone or followed by post-exercise cardio. Fourteen participants followed a fat loss–focused program that used supersets, shorter rest periods, and added post-exercise cardio, while thirteen followed a muscle gain–focused program with longer rest periods and slightly heavier loads. Body composition was assessed using bioimpedance, muscle circumferences were measured, and strength was estimated across several key exercises.
What did they find? The fat loss program led to greater reductions in body fat than the muscle gain program, although this group also started with higher baseline body fat levels. The fat loss group showed statistically significant reductions in chest, waist, and hip circumferences. Both groups demonstrated statistically significant improvements in estimated maximal strength, with no meaningful differences between programs.
What does it mean for you? For untrained individuals aiming to lose fat, adding post-exercise cardio to resistance training led to greater reductions in body fat without compromising strength gains. However, these findings reflect a self-selected group with higher starting body fat and should not be assumed to apply equally to trained lifters or leaner populations.

What’s the Problem?

In Issue 38 of REPS, I wrote an article that covered concurrent training, focusing on a study by Li et al 1 that examined whether the order of strength and endurance training influenced changes in body composition, strength, and power. The authors reported that concurrent training improved body composition and several performance measures in young overweight men, and that completing resistance training before endurance work led to greater improvements in some outcomes.

While we are not revisiting concurrent training with the question of whether cardio “kills your gains,” it is worth briefly reiterating the broader evidence base. In general, concurrent training does not appear to meaningfully impair strength gains in untrained individuals, though it may have a greater impact in trained lifters 2. For resistance trained individuals looking to add endurance training, separating strength and endurance sessions by at least two hours may help minimize any potential negative effects 3.

However, the question addressed in the current study is slightly different. Rather than focusing on training order or whether concurrent training compromises strength, the authors examined whether adding aerobic training to a resistance training program improves body composition, and whether this addition affects strength outcomes. With that in mind, let’s take a closer look at what they did.

Purpose

The study compared two training programs framed around fat loss or muscle gain goals in untrained men who self-selected their training approach, using resistance training either alone or combined with post-exercise aerobic activity.