PROBLEM: It is unknown if vagal modulation differs during recovery between free-weight (FW) and weight machines (MW). METHODS: Resistance-trained individuals completed acute FW (n = 25) or WM (n = 16) resistance exercises. Autonomic modulation was collected at rest, 15 (Rec1), and 25 (Rec2) min following acute resistance exercise (ARE) or a control. Sample Entropy (SampEn) and normalized high frequency (HFnu) were indicative of vagal modulation. A 2x2x3 ANCOVA was used to examine group (FW, WM) across conditions (ARE, control) and time (Rest, Rec1, Rec2), with load as a covariate. RESULTS: The groups were similar for baseline autonomic modulation. There was a significant group by condition by time interaction (p=0.03) for SampEn such that in the FW group (Rest: 1.5±0.3; Rec1: 1.1±0.3; Rec2: 1.1±0.4) it was attenuated during Rec1 and Rec2 after ARE compared to rest and the control. In the MW group, while there were no significant differences from rest to Rec1, there was a significant difference from Rec1 to Rec2 (Rest: 1.4±0.5; Rec1: 1.0±0.3; Rec2: 1.3±0.3) during recovery that was different from the control. There was also a significant group by time interaction for HFnu (Rest: 62.5±15.0; Rec1: 29.5±18.9%; Rec2: 29.2±19.9%, p=0.002) such that it was attenuated compared to rest, and the control, in both groups. CONCLUSION: Based on our data the use of free-weight resistance exercises results in significant reductions in vagal modulation that are maintained, up to 30 min, which does not appear to occur when using weight machines.