When it comes to strength training, most gym-goers focus on sets, reps, and load. But there’s another powerful variable often overlooked: Time Under Tension (TUT). This refers to how long your muscles are under strain during a set of resistance training. Whether you’re lifting heavy to build strength or training for hypertrophy (muscle growth), understanding and applying the right TUT could maximize your results.

So what’s the best TUT? Is 30 seconds enough? Does 60 seconds yield more gains? Let’s explore what current research says.

What Is Time Under Tension (TUT)?

TUT is the total duration your muscles are actively working during a set. For example, if you perform 10 repetitions of a bicep curl and each repetition takes 4 seconds (2 seconds up, 2 seconds down), the TUT is 40 seconds.

This is important because different TUT ranges trigger different adaptations:

• Short TUT (under 20’s): Primarily increases strength and power.
• Moderate TUT (30–45’s): Improves both strength and hypertrophy.
• Long TUT (45–60+ sec.): Maximizes muscle hypertrophy and metabolic stress.

What the Research Shows

1. TUT and Muscle Growth

A 2015 review by Schoenfeld et al. found that sets lasting between 30 and 60 seconds were optimal for muscle hypertrophy. This duration allows for sufficient muscle fiber recruitment and metabolic stress, two key triggers for growth. (Schoenfeld, 2015)

2. Tempo Impacts Hypertrophy

In a study by Burd et al. (2012), lifters who used slower tempos (creating longer TUTs) had higher rates of muscle protein synthesis than those who lifted quickly, even with equal total load. Their conclusion? TUT matters more than the number of reps. (Burd et al., 2012)

3. 60 Seconds: The Hypertrophy Sweet Spot

A 2016 study by Martins-Costa et al. found that longer TUTs—especially close to 60 seconds—generated more muscle activation and blood lactate buildup. These physiological responses are closely linked to muscle growth. (Martins-Costa et al., 2016)

4. TUT and Strength

While muscle growth is linked to longer TUT, strength training benefits from a shorter TUT (20–40 seconds), achieved with heavier weights and lower reps. A 2020 review by Wilk et al. suggests that manipulating TUT through slower eccentrics (lowering phase) can boost both strength and size, depending on set duration and load. (Wilk et al., 2020)

Which TUT is Best?

30 Seconds of TUT

• Typically 6–8 reps at normal tempo (2-0-2)
• Best for developing pure strength
• Useful for athletes focusing on load and neural adaptations
• Not optimal alone for hypertrophy

45 Seconds of TUT

• Around 10 reps at slower tempo (3-1-2)
• Good for both strength and size
• Balance between mechanical tension and metabolic fatigue
• Excellent for compound lifts like squats and bench press

60 Seconds of TUT

• Around 12–15 reps with slow tempo (4-0-2)
• Best for hypertrophy and muscle endurance
• Maximizes time muscles spend working under load
• Ideal for accessory movements like lateral raises, curls, and machine work

How to Apply TUT in Your Training

1. Choose Your Tempo Wisely
   Tempo is written as 4 digits: eccentric – pause – concentric – pause.
   • Example: 3-1-2-0 (3 sec down, 1 sec pause, 2 sec up, no pause at top)
   • Slowing tempo increases TUT even without adding reps.
2. Use TUT to Match Your Goal
   • Strength: 3–6 reps with heavy weight, TUT of 20–40 sec
   • Hypertrophy: 8–12 reps, moderate weight, TUT of 45–60 sec
3. Try Slow Eccentrics
   Slowing the eccentric (lowering) phase enhances both TUT and mechanical tension, a proven combo for hypertrophy.
4. Track Your TUT
   Don’t just count reps—count seconds. Use a stopwatch or metronome to maintain consistent TUT per set.

Sample Hypertrophy Workout Using TUT

Goal: Muscle Growth
TUT Range: 45–60 seconds
Tempo: 3-1-2
Rest Between Sets: 60–90 seconds

Final Thoughts

Time Under Tension (TUT) is a science-backed way to optimize your workouts—especially when building muscle mass and strength is your goal. While shorter TUTs (30 seconds) are great for max strength, research consistently shows that 45 to 60 seconds of TUT per set is the ideal range for maximizing hypertrophy.

Whether you’re lifting at home or in the gym, slowing your tempo and focusing on how long your muscles are working could make a significant difference in your training outcomes. Try it in your next Jefit workout and track your results over time.

Jefit: Your Ultimate Strength Training Companion

If you’re committed to building muscle, gaining strength, and tracking your progress effectively in 2025, the Jefit strength training app is the essential tool to help you crush your fitness goals. With over 20 million downloads and 12+ million active users, Jefit ranks among the best strength training apps available today. Named the Best Fitness App of 2024 and featured in Men’s Health, PC Magazine, and USA TODAY, Jefit combines expert-built workout programs, advanced gym performance tracking, and a supportive community to help you stay accountable and motivated. Whether you’re looking to follow a scientifically-backed muscle-building plan, monitor your lifting progress, or optimize your training intensity, Jefit gives you everything you need — all in one place.

References

• Schoenfeld, B. J. (2015). The mechanisms of muscle hypertrophy and their application to resistance training. J Strength Cond Res, 24(10), 2857–2872.
• Burd, N. A., et al. (2012). Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume. J Appl Physiol, 112(3), 540–545.
• Martins-Costa, H. C., et al. (2016). Longer repetition duration increases muscle activation and blood lactate response. J Sports Med Phys Fitness, 56(12), 1492–1499.
• Wilk, M., et al. (2020). Tempo training in resistance exercise: The need for a deeper understanding. J Hum Kinet, 72, 79–91.

Michael Wood, CSCS, is a Certified Strength & Conditioning Specialist and Content Manager for JeFit app. Michael is a former Assistant Strength & Conditioning Coach at the University of Connecticut and Exercise Physiologist at the USDA Human Nutrition Research Center on Aging at Tufts University. He is the Founder of Michael Wood Fitness, named twice to “Top 100 Trainers in America” by Men’s Journal and voted Best of Boston by Boston Magazine. Michael previously taught at the University of Connecticut and Boston University. He is the author of TBC30: 6 Steps to a Stronger, Healthier You.

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