All of you regularly participate in weight training at our facility somewhere between 1-4 times per week, but are you aware of the changes happening in your body while you lift? There are three primary muscular changes that occur after resistance training: Increased muscle size (hypertrophy), muscle fiber transition (I’ll explain), and enhanced muscular structure. Each of these changes leads to an increased ability to produce force, power, and endurance.
Muscle hypertrophy is simply the increase in muscle size—think of your biceps after consistent curls. Each rep creates tiny amounts of stress and micro-damage within the fibers. Not to worry as this damage isn’t harmful, rather it signals your body to release key hormones (testosterone, growth hormone, cortisol, etc.) that repair and rebuild tissue. Over time your body produces more proteins called actin and myosin, which thicken the muscle fibers, leading to visible growth. With consistent training, these changes typically become noticeable within 6–20 weeks.
Muscle fiber transition: Your muscles contain a mix of three fiber types-
Type I – slow-twitch, endurance-focused
Type IIa – fast-twitch, versatile and powerful
Type IIx – fast-twitch, explosive and short-duration
The proportion of each type depends on genetics, activity, and training. Resistance training can shift fibers from one type to another. For example, a marathon runner tends to have more Type I fibers for endurance. Adding strength training, however, can increase Type IIa fibers, improving force production, speed, and versatility.
Finally, muscle structure change refers to how resistance training alters the internal structure of your muscles. Each muscle is packed with microscopic fibers that hold the “ingredients” for strength and growth. As you consistently challenge them—say, with weeks of biceps curls—your body adapts by increasing muscle size, improving contraction strength, speeding up repair, and even enhancing your hormonal response.
Weight training is more than just building muscle; it’s about creating lasting changes that support strength, health, and longevity. Take care of your body today, and your future self will thank you.
-Nick, Tom, and Hunter
