One of the most debated topics in resistance training is whether low reps or high reps are better for muscle growth and strength development. Some argue that lifting heavy with fewer reps is optimal for building strength, while others claim that higher reps with lighter weights are better for hypertrophy.
But what does the science say?
The Science of Strength Training
Source: Martin CowieLow Reps for Maximal Strength
Strength training is defined by the ability to produce maximal force, which is largely determined by neuromuscular efficiency and muscle fibre recruitment.
Research shows that training with low repetitions (typically 1-5 reps per set) and heavy loads (above 85% of one-rep max) maximises motor unit recruitment and enhances neural adaptations (Suchomel et al., 2018). This leads to increased intermuscular and intramuscular coordination, allowing lifters to handle heavier weights over time.
A study by Schoenfeld et al. (2017) compared low-rep (3-5 reps) and moderate-rep (8-12 reps) training protocols. It found that while both groups increased muscle size, the low-rep group had significantly greater strength gains. This aligns with previous research showing that training with heavy loads induces superior improvements in maximal strength due to increased central nervous system efficiency (Sale, 1988).
High Reps for Muscle Growth
Muscle hypertrophy is driven primarily by mechanical tension, muscle damage, and metabolic stress (Schoenfeld, 2010). High-rep training (12-20 reps per set) with moderate loads (60-75% of one-rep max) creates more metabolic stress, increasing muscle swelling and the release of anabolic hormones such as growth hormone and IGF-1 (Kraemer et al., 1990).
Research indicates that high-rep training can be just as effective as low-rep training for hypertrophy, provided that sets are taken close to failure. A study by Schoenfeld et al. (2014) found that both low-rep (3-5 reps) and high-rep (25-35 reps) groups achieved similar muscle growth over an 8-week period when sets were taken to failure.
Mechanisms Behind Strength and Hypertrophy Gains
Neural Adaptations vs. Muscle Adaptations
Low-rep, high-load training is effective for strength because it enhances neural drive, increasing the rate at which the nervous system activates muscle fibres (Folland & Williams, 2007). High-rep training, on the other hand, increases muscle cross-sectional area by promoting greater muscle protein synthesis and sarcoplasmic hypertrophy (Ogborn & Schoenfeld, 2014).
Fibre Type Recruitment
Low reps with heavy loads primarily recruit type II fast-twitch muscle fibres, which are responsible for explosive strength and power (Enoka & Duchateau, 2017). High-rep training, however, recruits both type I and type II fibres, leading to greater overall muscle fatigue and endurance adaptations.
Practical Application: Which One Should You Choose?
Strength-Focused Training
If your goal is to maximise strength, focusing on low-rep, high-intensity training is optimal. Powerlifters, Olympic weightlifters, and athletes requiring maximal force production benefit most from training in the 1-5 rep range with heavy loads, as it improves neuromuscular efficiency and maximises force output (Suchomel et al., 2018).
Hypertrophy-Focused Training
For muscle size, higher rep ranges (8-15 reps) with moderate loads ensure sufficient mechanical tension while inducing greater metabolic stress (Schoenfeld, 2010). Bodybuilders and physique athletes typically train in this range to optimise muscle growth.
The Best of Both Worlds: Periodisation
The most effective approach for both strength and hypertrophy is a combination of low-rep and high-rep training. Periodisation, which involves varying rep ranges and intensities across training cycles, has been shown to improve both muscle growth and strength adaptations (Kraemer & Ratamess, 2004). A study by Rhea et al. (2002) demonstrated that a periodised program resulted in greater strength and hypertrophy compared to non-periodised training.
Conclusion
Both low-rep and high-rep training have their place depending on individual goals. Low reps with heavy loads optimise neural adaptations and maximal strength, while high reps with moderate loads enhance muscle hypertrophy through metabolic stress and increased muscle endurance. The best approach is to incorporate both rep schemes through periodisation, ensuring a balanced development of strength and size.
Key Takeaways
| Factor | Low Reps (1-5) | High Reps (12-20) |
|---|---|---|
| Strength Gains | Optimal | Moderate |
| Hypertrophy | Moderate | Optimal |
| Neural Adaptations | High | Low |
| Metabolic Stress | Low | High |
| Fibre Type | Type II (Fast-Twitch) | Type I & Type II |
| Training Goal | Powerlifting, Strength Sports | Bodybuilding, Muscle Endurance |
| Best Approach | Periodisation Combining Both |
References
Enoka, R. M., & Duchateau, J. (2017). Muscle fatigue: what, why and how it influences muscle function. The Journal of Physiology, 595(11), 2859-2879.
Folland, J. P., & Williams, A. G. (2007). The adaptations to strength training. Sports Medicine, 37(2), 145-168.
Kraemer, W. J., & Ratamess, N. A. (2004). Fundamentals of resistance training: progression and exercise prescription. Medicine & Science in Sports & Exercise, 36(4), 674-688.
Kraemer, W. J., et al. (1990). Hormonal and growth factor responses to heavy resistance exercise protocols. Journal of Applied Physiology, 69(4), 1442-1450.
Ogborn, D., & Schoenfeld, B. J. (2014). The role of fiber types in muscle hypertrophy: implications for loading strategies. Strength & Conditioning Journal, 36(2), 20-25.
Rhea, M. R., et al. (2002). Periodized training strategies for strength and hypertrophy. Journal of Strength and Conditioning Research, 16(4), 250-255.
Image Sources
- crossfit-weightlifting: Martin Cowie
Was this article helpful?
