Understanding Your Muscle Growth
At Clarence Park Health Suite, we often hear members asking about the 'best' way to train. Should you lift heavy for low reps, or go for the 'pump' with higher volume? Recent research, including a 2025 study on muscle hypertrophy, has reignited the conversation around two distinct types of muscle growth: myofibrillar and sarcoplasmic hypertrophy. Understanding these can help you tailor your individual gym access or 1-to-1 personal training sessions to better meet your goals.
The Two Paths to Growth
To put it simply, your muscles grow in two primary ways:
- Myofibrillar Hypertrophy: This is often associated with 'functional' growth. It involves the increase in the size and number of the contractile proteins (myofibrils) within the muscle fiber. This is the type of growth typically stimulated by heavy, low-repetition strength training.
- Sarcoplasmic Hypertrophy: This refers to an increase in the volume of the sarcoplasm—the fluid and energy stores surrounding the myofibrils. This is often the 'pump' you feel after higher-repetition sets, which can contribute to a fuller look in the muscle.
What the Science Says
A 2025 study involving healthy male volunteers compared these two training styles over an eight-week period. The researchers looked at changes in muscle thickness across the chest, shoulders, and thighs. While both methods are effective for building muscle, the research suggests that your training style acts as a signal to your body on how to adapt.
For those of you looking to improve your overall fitness, the takeaway is not to choose one over the other, but to understand that your training volume and intensity dictate the outcome. If your goal is raw strength, prioritizing myofibrillar-focused training (heavier loads, longer rest periods) is key. If you are looking for muscle fullness, incorporating higher-volume, moderate-load training can be highly effective.
Practical Application for Your Gym Routine
Whether you are training solo or working with a personal trainer, you can apply these findings to your routine at our gym:
- Vary Your Rep Ranges: Don't get stuck in a rut. If you usually train in the 8–12 rep range, try a block of 4–6 reps to focus on myofibrillar density, followed by a block of 12–15 reps to encourage sarcoplasmic volume.
- Focus on Quality: Regardless of the rep range, ensure your form is consistent. The research on muscle growth consistently shows that the proximity to failure is a major driver of results, regardless of whether you are training for density or volume.
- Listen to Your Body: Because sarcoplasmic training often involves higher volume, it can be more taxing on your recovery. Ensure you are allowing adequate rest between your gym sessions to let your muscles adapt to the stimulus.
Why It Matters at Clarence Park
We believe that the best gym environment is one where you feel empowered to experiment with your training. By understanding the science behind how your muscles respond to different stimuli, you can make more informed decisions about your workouts. Whether you are here for a quick session or a detailed 1-to-1 personal training plan, knowing the 'why' behind your training can make all the difference in your progress.
Next time you step onto the gym floor, think about your goal for the day. Are you building the engine, or filling the tank? Both are essential parts of a well-rounded fitness journey.