BACKGROUND: The study aimed to assess whether prior intake of metformin enhances performance in the FRAN workout, a popular Functional Fitness Training protocol. METHODS: Fourteen men (mean±SD: 24.2±3.5 years
height: 173.3±7.8 cm
weight: 78.3±14.1 kg
body mass index: 25.9±3.0 kg/m RESULTS: Significant differences were observed in partial times between rounds (F=28.91
P<
0.01), but no significant differences were found between metformin and placebo conditions (F=0.08
P=0.77) or interaction effects (F=0.87
P=0.42). Similarly, total time differed significantly between rounds (F=158.04
P<
0.01), with no significant differences between conditions (F=0.02
P=0.88) or interaction effects (F=0.30
P=0.73). CONCLUSIONS: Acute metformin intake did not enhance FRAN workout performance, nor did it affect heart rate or perceived exertion. Coaches and athletes should consider that metformin's impact on exercise performance appears nonexistent, and its use in this context might not provide the desired ergogenic effect.