When it comes to chest hypertrophy, the tempo of your repetitions can significantly impact muscle growth. Some argue that explosive movements recruit more muscle fibres and improve power output, while others claim that slow, controlled reps increase time under tension (TUT), which is crucial for muscle growth.
But which one is truly superior for building chest mass? In this article, we will analyse both training tempos, referencing scientific studies to determine which method is most effective for chest development.
The Science Behind Tempo and Muscle Growth
Understanding Muscle Hypertrophy
Muscle hypertrophy occurs when muscle fibres undergo mechanical tension, metabolic stress, and muscle damage. According to Schoenfeld (2010), mechanical tension is the primary driver of muscle growth, while metabolic stress and muscle damage contribute to a lesser extent. The tempo of a lift influences these factors differently, impacting the extent of hypertrophy.
Explosive Training: Maximising Muscle Fibre Recruitment
Explosive reps, often characterised by a fast concentric (lifting) phase, typically around 0.5 to 1 second, are commonly used in strength and power training. Studies have shown that lifting explosively increases type II muscle fibre recruitment (Campos et al., 2002). These fast-twitch fibres have the highest potential for growth and force production. Furthermore, a study by Newton et al. (1996) demonstrated that explosive bench press movements led to greater activation of pectoral and triceps muscles compared to slower lifts. The rapid force production in explosive training also enhances neuromuscular efficiency, improving overall strength gains (Cormie et al., 2011).
Slow Tempo Training: The Role of Time Under Tension
Slow-tempo training emphasises controlled, prolonged eccentric and concentric phases, typically around 3-6 seconds per phase. A study by Burd et al. (2010) found that slower rep tempos increase time under tension, leading to greater protein synthesis post-exercise. Additionally, Schoenfeld et al. (2015) demonstrated that when participants performed slower repetitions, they experienced more significant metabolic stress, which has been linked to hypertrophy. The increased TUT allows for prolonged mechanical tension, a critical factor in muscle growth.
Comparing Muscle Activation and Growth
Muscle Activation in Explosive vs Slow Reps
Electromyography (EMG) studies have provided insight into muscle activation differences between explosive and slow training. A study by Wilk et al. (2020) found that explosive reps resulted in higher peak activation of the pectoralis major, particularly during the concentric phase. However, slow tempo reps maintained a high level of activation throughout the entire lift, leading to sustained muscle engagement.
Training Volume and Fatigue
Explosive training allows for higher training volume due to reduced fatigue per rep, enabling lifters to perform more total repetitions with heavier loads. This can be advantageous for strength and hypertrophy, as total volume is a key driver of muscle growth (Schoenfeld et al., 2014). Conversely, slow tempo training induces greater muscle fatigue per rep, potentially limiting overall volume. However, it enhances metabolic stress, which may contribute to hypertrophy (Schoenfeld, 2010).
Practical Application: Which One Should You Choose?
Training Goals and Experience Level
For individuals looking to maximise chest growth, incorporating both explosive and slow tempo reps may be optimal. Beginners can benefit from slower reps to build neuromuscular control and muscle endurance, while advanced lifters may leverage explosive training for improved strength and power output.
Programming for Maximum Hypertrophy
A balanced approach could include explosive reps for heavy compound lifts, such as the bench press, to stimulate type II fibres, while incorporating slow tempo training in accessory movements like dumbbell flyes to enhance time under tension. Research by Schoenfeld et al. (2015) suggests that varying rep tempo within a training programme can optimise hypertrophic adaptations.
Practical Example
- Explosive Training: 3-5 sets of 3-5 reps at 85-90% 1RM on the bench press, focusing on rapid concentric movement.
- Slow Tempo Training: 3-4 sets of 8-12 reps at 65-75% 1RM on incline dumbbell press, with a 3-4 second eccentric phase.
Conclusion
Both explosive and slow tempo training have unique benefits for chest hypertrophy. Explosive reps enhance type II fibre recruitment and neuromuscular efficiency, while slow tempo reps increase time under tension and metabolic stress. Incorporating both into a structured programme can maximise muscle growth and overall chest development.
Key Takeaways
| Training Method | Benefits | Drawbacks |
|---|---|---|
| Explosive Tempo | Increases type II fibre recruitment, enhances strength and power, allows for higher training volume | Lower time under tension, increased injury risk with poor form |
| Slow Tempo | Maximises time under tension, increases metabolic stress, enhances muscle control | Higher fatigue per rep, potentially lower total volume |
References
Burd, N.A., et al. (2010). “Muscle time under tension during resistance exercise stimulates differential protein subfractional synthetic responses in men.” Journal of Applied Physiology, 109(1), 47-54.
Campos, G.E., 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), 50-60.
Cormie, P., et al. (2011). “Neuromuscular adaptations to power versus strength training.” Sports Medicine, 41(2), 125-146.
Newton, R.U., et al. (1996). “Influence of load and stretch shortening cycle on the kinematics, kinetics and muscle activation that occurs during explosive upper-body movements.” European Journal of Applied Physiology and Occupational Physiology, 75(4), 333-342.
Schoenfeld, B.J. (2010). “The mechanisms of muscle hypertrophy and their application to resistance training.” Journal of Strength and Conditioning Research, 24(10), 2857-2872.
Schoenfeld, B.J., et al. (2014). “The effect of training volume on muscular hypertrophy: a meta-analysis.” European Journal of Sport Science, 14(5), 527-536.
Schoenfeld, B.J., et al. (2015). “Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men.” Journal of Strength and Conditioning Research, 29(10), 2909-2919.
Wilk, M., et al. (2020). “The influence of movement tempo on muscular activation in resistance training: A systematic review and meta-analysis.” Sports Medicine, 50(2), 183-197.
