When it comes to building muscle, many lifters focus on the basics: increasing the weight, perfecting their form, and ensuring they hit the right number of reps and sets. While these fundamentals are undoubtedly important, there is one aspect of resistance training that is often overlooked yet plays a crucial role in muscle growth: time-under-tension (TUT). This concept is vital for those looking to optimise hypertrophy (muscle growth) during their weightlifting workouts. In this article, we will delve into what time-under-tension is, the benefits of incorporating it into your training routine, how to properly utilise it, and the results you can expect when applied correctly.
What is Time-Under-Tension?
Time-under-tension refers to the total duration your muscles are under stress during a set of resistance exercises. This concept places an emphasis on how long a muscle is working during a lift, rather than just focusing on the number of reps or the amount of weight lifted. Typically, a traditional rep might take 1-2 seconds on the concentric phase (muscle shortening) and 2-3 seconds on the eccentric phase (muscle lengthening). However, in TUT training, the goal is to slow down both phases of the lift, increasing the amount of time your muscles are under strain.
The duration of time your muscles spend under tension has a significant impact on the stimuli they receive. This time-focused approach stresses the muscles in a different way than conventional lifting, and research has shown that varying the TUT can influence hypertrophy, strength gains, and endurance outcomes. In the context of hypertrophy, TUT training is particularly useful as it maximises mechanical stress and metabolic fatigue, which are both essential factors for muscle growth (Schoenfeld, 2010).
Benefits of Time-Under-Tension for Hypertrophy
Time-under-tension training offers several key benefits for hypertrophy-focused athletes. These include:
1. Increased Muscle Activation
By slowing down the tempo of each rep, TUT training increases the activation of muscle fibres. During slower, controlled movements, your muscles are forced to work harder throughout the entire range of motion. This increased activation promotes the recruitment of a greater number of muscle fibres, particularly type II fibres, which are the fast-twitch fibres most associated with hypertrophy (Campos et al., 2002).
2. Enhanced Muscle Damage
Muscle growth occurs when the muscle fibres are damaged and subsequently repaired, a process known as muscle remodelling. Eccentric contractions (the lowering phase of the lift) are particularly effective at causing muscle damage, and lengthening the time spent in this phase can increase the stimulus for hypertrophy. A longer TUT ensures more muscle micro-tears, triggering the body’s repair mechanisms and leading to increased muscle size (Schoenfeld et al., 2017).
3. Greater Metabolic Stress
Time-under-tension prolongs the period in which your muscles are deprived of oxygen, leading to a build-up of metabolic by-products such as lactate. This is referred to as metabolic stress, another crucial driver of hypertrophy. The burn you feel during a high-TUT set is a sign of this stress, which has been linked to muscle growth through cell swelling and the upregulation of anabolic pathways (Schoenfeld, 2013).
4. Improved Mind-Muscle Connection
A slower, more controlled lifting tempo enables better focus on the muscles being targeted. This enhances the mind-muscle connection, a psychological factor that can improve muscle activation and help prevent compensatory movements that reduce the effectiveness of the exercise. By increasing your awareness of the muscle contraction, TUT training helps you focus more precisely on the muscles being worked.
How to Utilise Time-Under-Tension in Your Training Routine
Incorporating time-under-tension into your training does not necessarily mean completely overhauling your existing workout plan. Instead, TUT training can be integrated into your current routine in several effective ways. Here’s how you can make the most of it:
1. Adjust Your Tempo
The most straightforward way to apply TUT is to adjust the speed of your lifts. Focus on slowing down both the concentric and eccentric phases of the movement. For example, instead of performing a standard bicep curl in 2 seconds, try using a tempo of 3 seconds up (concentric phase) and 3 seconds down (eccentric phase). This would increase the TUT for a set of 10 reps from 20 seconds to 60 seconds.
A commonly recommended tempo for hypertrophy-focused TUT is 4-2-1-0 (four seconds for the eccentric phase, two-second pause at the bottom, one second for the concentric phase, and no pause at the top), though this can be adjusted based on the specific exercise and individual preferences. The key is to maintain control throughout the movement, avoiding momentum and ensuring continuous tension on the muscle.
2. Choose the Right Load
Since TUT training requires you to lift for longer periods, it’s important to select a weight that allows you to maintain proper form throughout the entire set. Lifting too heavy may compromise your ability to control the movement, while lifting too light may reduce the overall intensity of the exercise. The sweet spot is typically between 60-70% of your one-rep max (1RM), allowing for moderate repetitions (8-12) with an extended time-under-tension.
3. Incorporate TUT with Different Rep Ranges
While TUT is often associated with moderate rep ranges (8-12), you can vary your rep ranges to target different aspects of muscle growth. For example, longer TUT with higher reps (12-15) can increase metabolic stress, while shorter TUT with lower reps (6-8) can enhance mechanical tension and strength. By combining different TUT strategies across your workouts, you can stimulate hypertrophy from multiple angles (Grgic et al., 2017).
4. Focus on Isolation Movements
While TUT can be applied to compound exercises such as squats and deadlifts, it tends to be particularly effective for isolation movements where strict control is easier to maintain. Exercises like bicep curls, tricep extensions, and lateral raises are ideal for experimenting with TUT, as you can maintain continuous tension on the target muscle without relying on secondary muscles to assist in the movement.
Results: What Can You Expect?
When properly applied, time-under-tension training can lead to noticeable increases in muscle size and definition. A 2016 study published in the Journal of Sports Sciences compared the effects of different TUT durations on hypertrophy and found that participants who trained with longer TUT experienced greater increases in muscle cross-sectional area compared to those with shorter TUT (Tanimoto et al., 2016).
In terms of time frame, hypertrophy is a gradual process that requires consistent effort over months. However, many lifters report increased muscle fullness and better muscle activation within a few weeks of implementing TUT training. Additionally, because TUT places significant stress on the muscles, it can lead to improvements in muscle endurance, making it easier to perform longer sets with heavier weights over time.
While TUT is not a magic bullet for hypertrophy, it provides a highly effective method for breaking through plateaus and stimulating new muscle growth. It’s particularly useful for experienced lifters who have already mastered the basics and are looking for ways to optimise their training.
Combining TUT with Other Training Methods
Time-under-tension is most effective when combined with other proven hypertrophy strategies such as progressive overload and proper nutrition. Progressive overload—the gradual increase of weight or volume over time—remains the cornerstone of muscle growth, and TUT can be used as a supplementary tool to enhance this principle. For example, you can periodically incorporate TUT phases into your training, alternating between traditional lifting and TUT to keep your muscles adapting to new stimuli.
Additionally, adequate protein intake and recovery are essential for maximising the benefits of TUT training. Since TUT leads to greater muscle damage, ensuring you consume enough protein to support muscle repair (1.6-2.2g per kg of bodyweight) and allowing for sufficient rest between sessions will be crucial for achieving the best results (Morton et al., 2018).
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Time-under-tension is a useful yet often underutilised tool in the world of hypertrophy training. By focusing on the amount of time your muscles are under strain, you can significantly increase muscle activation, enhance metabolic stress, and promote the kind of muscle damage necessary for growth. When combined with proper form, progressive overload, and a well-rounded nutrition plan, TUT training can help lifters break through plateaus and achieve noticeable gains in muscle size and endurance.
Whether you’re a beginner looking to build your first few pounds of muscle or an experienced lifter aiming to fine-tune your physique, incorporating time-under-tension into your routine could be the key to unlocking new levels of hypertrophy.
References
Campos, G. E., Luecke, T. J., Wendeln, H. K., Toma, K., Hagerman, F. C., Murray, T. F., … & Staron, R. S. (2002). Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. European Journal of Applied Physiology, 88(1), 50-60.
Grgic, J., Schoenfeld, B. J., Skrepnik, M., Davies, T. B., & Mikulic, P. (2017). Effects of rest interval duration in resistance training on measures of muscular strength, hypertrophy, and muscular endurance: A systematic review. Sports Medicine, 48(1), 75-95.
Morton, R. W., Murphy, K. T., McKellar, S. R., Schoenfeld, B. J., Henselmans, M., Helms, E., … & Phillips, S. M. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376-384.
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. (2013). Potential mechanisms for a role of metabolic stress in hypertrophic adaptations to resistance training. Sports Medicine, 43(3), 179-194.
Schoenfeld, B. J., Ogborn, D., & Krieger, J. W. (2017). Effects of resistance training frequency on measures of muscle hypertrophy: A systematic review and meta-analysis. Sports Medicine, 46(11), 1689-1697.
Tanimoto, M., & Ishii, N. (2016). Effects of low-intensity resistance exercise with slow movement and tonic force generation on muscular function in young men. Journal of Sports Sciences, 34(12), 1090-1098.