The debate between high-rep and low-rep training is a longstanding one in the fitness community. Both methods have their advocates and distinct benefits, but when it comes to upper body muscle growth, the choice depends on factors such as your goals, training experience, and individual response to exercise.
This article delves into the science behind high-rep and low-rep training, outlining their benefits and drawbacks to help you make an informed decision.
What Is High-Rep and Low-Rep Training?
High-Rep Training
High-rep training typically involves performing 12 to 20 or more repetitions per set with lighter weights. This method is often associated with muscular endurance and hypertrophy in slow-twitch muscle fibres. High-rep training can enhance metabolic stress, a key mechanism in muscle growth, by increasing time under tension (TUT).
Low-Rep Training
Low-rep training usually consists of 1 to 6 repetitions per set with heavier weights, focusing on strength development and hypertrophy in fast-twitch muscle fibres. This approach is ideal for increasing maximal strength and activating high-threshold motor units, which play a significant role in muscle growth.
The Science of Muscle Growth
Muscle hypertrophy, or growth, occurs through three primary mechanisms: mechanical tension, metabolic stress, and muscle damage. Each of these can be influenced by the number of repetitions performed.
Mechanical Tension
Mechanical tension is generated when muscles contract under heavy loads. Low-rep training excels in this area due to the high resistance used, which maximally recruits muscle fibres. A study by Schoenfeld (2010) highlighted the importance of mechanical tension in promoting hypertrophy.
Metabolic Stress
Metabolic stress refers to the accumulation of metabolites such as lactate during exercise. High-rep training is more effective at creating metabolic stress due to prolonged TUT and higher rep counts. This metabolic environment has been shown to trigger anabolic signalling pathways, enhancing muscle growth (Schoenfeld, 2013).
Muscle Damage
Muscle damage occurs when fibres sustain microtears during exercise. Both high-rep and low-rep training can cause muscle damage, but the extent depends on the intensity and volume. While low-rep sets with heavier weights can induce greater mechanical strain, high-rep sets can also cause significant damage due to fatigue and eccentric loading.
High-Rep Training for Upper Body Muscle Growth
Benefits
- Metabolic Stress and Hypertrophy: High-rep training induces greater metabolic stress, a potent stimulus for muscle growth, particularly in slow-twitch fibres. Studies have shown that even lighter loads performed to failure can elicit similar hypertrophic responses to heavier loads (Schoenfeld et al., 2017).
- Improved Muscular Endurance: High-rep sets enhance the ability to sustain submaximal loads, beneficial for athletes or individuals focusing on functional fitness.
- Joint Health: Using lighter weights in high-rep training reduces stress on joints, making it a safer option for individuals with joint issues or those recovering from injury.
Drawbacks
- Limited Strength Gains: High-rep training does not maximise strength development, as the loads used are insufficient to recruit high-threshold motor units effectively.
- Time-Consuming: Performing higher repetitions increases workout duration, which may not be ideal for individuals with time constraints.
- Adaptation Plateau: Prolonged reliance on high-rep training can lead to diminishing returns as the body adapts to lighter loads.
Low-Rep Training for Upper Body Muscle Growth
Benefits
- Maximal Strength Gains: Low-rep training optimally recruits fast-twitch muscle fibres and high-threshold motor units, resulting in significant strength increases (Campos et al., 2002).
- Neuromuscular Adaptations: Heavy lifting improves neural efficiency, enhancing motor unit synchronisation and firing rates.
- Time Efficiency: Low-rep training requires fewer repetitions, making it a quicker way to achieve intense muscle stimulation.
Drawbacks
- Higher Injury Risk: Using heavier weights increases the risk of injury, particularly if form is compromised.
- Reduced Endurance: Low-rep training does not prioritise muscular endurance, limiting performance in extended efforts.
- Central Nervous System Fatigue: Heavy lifting places a significant load on the central nervous system (CNS), requiring longer recovery periods.
Comparing High-Rep and Low-Rep Training
Strength vs. Hypertrophy
Low-rep training is superior for building strength due to its focus on mechanical tension and neural adaptations. However, research indicates that hypertrophy can be achieved through both high-rep and low-rep training as long as sets are performed close to failure (Morton et al., 2016).
Fibre Type Activation
High-rep training primarily targets slow-twitch fibres, which are fatigue-resistant but have limited growth potential. Low-rep training activates fast-twitch fibres, which are more responsive to hypertrophy. Combining both approaches can ensure comprehensive fibre recruitment.
Practical Application
For upper body muscle growth, incorporating both high-rep and low-rep training can optimise results. For instance, low-rep sets can be used for compound lifts like bench presses to build strength, while high-rep sets can be included in accessory exercises such as lateral raises to induce metabolic stress.
Designing a Balanced Training Programme
Periodisation
Periodisation involves varying training variables such as intensity, volume, and rep ranges over time to avoid plateaus and maximise gains. Combining high-rep and low-rep training within a periodised plan ensures balanced development.
Example Programme
Day 1: Low-Rep Focus
- Bench Press: 4 sets of 4 reps
- Weighted Pull-Ups: 4 sets of 5 reps
- Overhead Press: 3 sets of 6 reps
Day 2: High-Rep Focus
- Dumbbell Flyes: 3 sets of 15 reps
- Cable Rows: 3 sets of 12 reps
- Lateral Raises: 4 sets of 20 reps
Conclusion
Both high-rep and low-rep training have unique advantages for upper body muscle growth. High-rep training enhances metabolic stress and muscular endurance, while low-rep training excels in building strength and recruiting fast-twitch fibres. Incorporating both methods within a well-structured programme, along with proper nutrition and recovery, is the key to optimising results.
Key Takeaways Table
Bibliography
- Campos, G.E.R., Luecke, T.J., Wendeln, H.K., et al., 2002. Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. European Journal of Applied Physiology, 88(1-2), pp.50-60.
- Morton, R.W., Oikawa, S.Y., Wavell, C.G., et al., 2016. Neither load nor systemic hormones determine resistance training-mediated hypertrophy or strength gains in resistance-trained young men. Journal of Applied Physiology, 121(1), pp.129-138.
- Schoenfeld, B.J., 2010. The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research, 24(10), pp.2857-2872.
- Schoenfeld, B.J., 2013. Potential mechanisms for a role of metabolic stress in hypertrophic adaptations to resistance training. Sports Medicine, 43(3), pp.179-194.
- Schoenfeld, B.J., Peterson, M.D., Ogborn, D., and Contreras, B., 2017. Effects of low- vs. high-load resistance training on muscle strength and hypertrophy in well-trained men. Journal of Strength and Conditioning Research, 31(12), pp.3508-3513.
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