Add Yahoo as a preferred source to see more of our stories on Google. Luis Alvarez/Getty Images Have you ever worked out and watched your muscles grow before your very eyes? You probably have, and ...

View post: Training for Your First HYROX? Try This 30-Minute Workout to Find Out What Race Day Will Feel Like Mixing salt and essential amino acids in water boosts workout hydration and muscle pump.

Who doesn't love a good biceps pump? Even the most devout exercise enthusiasts among us, who insist they train purely to feel good, can't deny there's something satisfying about watching your arms ...