Time Under Tension (TUT) vs. Explosive Reps: Which Style Builds More Muscle? (A 30-Day Comparison)

Fitness experts and exercisers love to debate—or even argue—about the best ways to build muscle, lose fat, and get in shape. Researchers also get in on the act, and there are hundreds of studies attempting to prove which training method or dietary approach is the most effective.   

Common issues of contention include: 

• Low-intensity steady-state cardio vs. high-intensity interval training
• Freeweights vs. machines
• High-volume vs. low-volume strength training
• Full body vs. split routines
• Intermittent fasting vs. six meals a day

Each of these approaches has merit and, confusingly, they can all provide good results. In fact, these arguments rarely have a clear winner, as the outcomes often depend on the individual.

Scientific studies don’t always help, as they’re often inconclusive. For every research paper supporting one point of view, you’ll probably find another that contradicts it. That’s because genetics, training history, age, recovery, and even daily stress levels all play a role in how your body responds to a given workout or diet approach.

In short, what works for one person may not work for another. The best way to find out what works for you? Try it—be your own experiment!

Lifting speed is another hotly debated topic and while the research suggests both slow and fast tempos can be similarly effective (1), I wanted to put them to the test and see which one worked better for me.  

So, for two weeks, I trained using slow, deliberate, TUT-focused reps. For the next two, I switched to fast, explosive lifting. I kept everything else—volume, exercises, rest, and diet—the same.

Here’s what happened—and which style seemed to build more muscle.

Time Under Tension (TUT) vs. Explosive Reps—What the Research Says

Training tempo—or how fast you lift and lower your weights—can have an impact on muscle growth. However, it’s not the only or most important factor. Research suggests that both slow, controlled reps (TUT) and fast, explosive reps can stimulate hypertrophy (muscle growth) and strength gains, though the mechanisms are somewhat different.

Slow, Controlled Reps

Slow, controlled reps keep your muscles under tension for longer, potentially boosting metabolic stress and muscle fiber recruitment—both of which are triggers for hypertrophy. Some studies show greater muscle activation with longer eccentric/lowering phases (2).

That said, slow reps usually require lighter weights, which could reduce overall muscle tension and training volume. As such, while lifting and lowering with greater control can build muscle, it’s less effective for building strength.

Related: Eccentric vs. Concentric Lifting

Explosive Reps

Explosive lifting involves producing a lot of force quickly. Fast reps allow you to train with heavier loads or do more reps before reaching failure. As such, explosive reps are good for improving muscle power and maximizing motor unit recruitment.

Research suggests that fast concentric reps, when taken near failure, can produce similar hypertrophy to slower lifting (3). This is probably due to the high levels of mechanical tension associated with fast, heavy reps.

What the Evidence Shows

While both slow and fast lifting have their advocates, the research is not conclusive and suggests that neither one nor the other training style is inherently superior. That’s because training outcomes often depend on the individual, and what works well for one person may not be so effective for another.

Here are three studies that give us a better idea of how both training styles can influence muscle growth:

• A 2015 meta-analysis by Schoenfeld et al. found no significant difference in muscle growth between rep tempos ranging from 0.5 to 8 seconds, as long as sets were taken to failure (4).
• A 2019 study by Wilk et al. noted that slower tempos can increase total time under tension, but may reduce training volume, suggesting a tradeoff between muscle fatigue and load (5).
• The American College of Sports Medicine states that “The eccentric phase appears particularly sensitive to slower tempos, while explosive concentrics may better stimulate type II fibers, which have greater growth potential (6).”

In summary, both slow reps and fast lifting can build muscle, and tempo is just one of the ingredients of an effective workout. The trick is to discover whether slow or fast reps work best for you.

To find out which style worked better for me, I decided to test both. Here’s how it went.

My One Month Slow vs. Fast Lifting Workout Program

To accurately compare slow and fast rep styles, I followed a structured four-week training plan. I did slow, controlled reps for two weeks and switched to explosive reps for the next two—all while keeping everything else the same.

This is the program I followed:

Weekly Split

Monday	Tuesday	Wednesday	Thursday	Friday	Saturday	Sunday
Lower Body – Knee Dominant	Upper Body – Horizontal Push and Pull	Rest	Lower Body – Hip Dominant	Rest	Upper Body – Vertical Push and Pull	Rest

Workout 1: Lower Body – Knee Dominant

1. Barbell back squat
2. Leg extension
3. Leg press
4. Forward lunge
5. Standing calf raise
6. Cable crunches

Workout 2: Upper Body – Horizontal Push and Pull

1. Barbell bench press
2. Pendlay row
3. Incline dumbbell bench press
4. Seated cable row
5. Cable rope pushdown
6. EZ bar curl

Workout 3: Lower Body – Hip Dominant

1. Barbell deadlift
2. Leg curl
3. Romanian deadlift
4. Barbell hip thrust
5. Seated calf raise
6. Hanging knee raises

Workout 4: Upper Body – Vertical Push and Pull

1. Barbell overhead press
2. Pull-up
3. Seated dumbbell press
4. Lat pulldown
5. EZ bar skull crusher
6. Seated dumbbell curl

Sets, Reps, and Tempo

As this was an experiment to determine whether slow or fast reps worked best for building muscle, I stuck to the most common set and rep scheme for that goal—3-4 sets of 8-12 reps per exercise.

However, for the first two weeks, I used a slow, controlled tempo where I lowered the weights for a count of three and raised them at the same speed. This meant that each rep took 6-8 seconds to complete, allowing for a 1-2 second pause between each one.

For the second two weeks, I lowered the weights using a controlled descent of 1-2 seconds and then lifted the weight as explosively as possible. Using this tempo, each rep took about 2-4 seconds to complete, and loads were generally a little higher than for the first two weeks.

With the plan in place, it was time to put both lifting styles to the test and see how my body responded.

Putting the Plan into Practice: Week-by-Week Breakdown

Each tempo brought its own challenges and benefits. Here’s a breakdown of how each two-week training block went and felt.

Weeks 1–2: Slow and Controlled

How The Workouts Felt

Training with a slow, controlled tempo meant reducing my training weights by 20-30%. This was quite a hard pill to swallow because, as a former powerlifter, I really enjoy testing my strength with heavy loads.

However, and contrary to what you might think, less weight does not necessarily mean easier workouts, and I had to concentrate hard to avoid speeding up as fatigue and lactic acid levels started to rise.

Pump And Muscle Activation

Controlled, slow reps keep your muscles under near-constant tension, which reduces blood flow into your muscles. They also prevent waste products from escaping.

The result? An awesome, skin-splitting pump!

While a pump isn’t necessarily a trigger for hypertrophy, the buildup of waste products and associated metabolic stress is. In addition, raising and lowering the weight so purposely increases that all-important mind-muscle connection.

Related: 6 False Positives of Effective Workouts

Recovery And Soreness

While I enjoy heavy strength training, I’ll be the first to admit that it can be exhausting. It takes a toll on your joints, connective tissues, muscles, and nervous system. Heavy leg workouts can leave me feeling exhausted for days.

Training with lighter loads and a controlled tempo was much less tiring, and I felt like I recovered faster between workouts. I also experienced very little joint pain. However, post-workout muscle soreness was severe, and far worse than I had expected. I put this down to the slow, controlled tempo and constant tension on my muscles.

Weeks 3–4: Fast and Explosive

How The Workouts Felt

Heavy weights and explosive concentrics put me back in my workout comfort zone—this is my preferred style of training. After two weeks of light, slow lifting, I was really looking forward to returning to something like my usual workouts.  

However, while the first two weeks of training definitely enhanced muscle growth, they did very little for my strength and power. Consequently, my first couple of explosive workouts felt awkward and unnatural—like my muscles weren’t quite firing properly. Thankfully, normal service soon resumed, and I quickly got back into my fast, heavy lifts.

Pump And Muscle Activation

In my experience, fast reps with heavy weights don’t produce the same pump as a slower tempo with lighter weights. Total time under tension is shorter, so blood doesn’t tend to accumulate in concentrated areas.

That said, my muscles felt much more “fired up” after a few sets of explosive lifting. It felt like they were working more efficiently and in a more coordinated way. This is why explosive lifting is most often associated with improved athletic performance.

Recovery And Soreness

Post-workout muscle soreness was no better or worse after switching to explosive lifting. This is probably because despite lifting fast, I still lowered the weights with control, and eccentric training is closely linked to delayed onset muscle soreness.

However, I did feel more tired during this two-week phase of training. Explosive lifting can be very taxing and takes a toll on your nervous system. This fatigue was not limited to individual muscles. Rather, my whole body felt tired.

Four-Week Summary

While both styles delivered solid results, they did so in different ways. Slow, controlled reps gave me a better pump, less joint stress, and surprising soreness—suggesting strong hypertrophic potential.

In contrast, explosive lifting reignited my strength, fired up my nervous system, and felt more like “me.”

After four weeks, it’s clear that both methods have value—and combining them might be the smartest move of all.

Closing Thoughts

After four weeks of testing, one thing became abundantly clear: there is more than one “best” way to train. Both slow and explosive reps produce results, albeit in different ways.

Your genetics, goals, preferences, and even your mindset matter, so don’t fall into the trap of chasing trends or blindly following studies. Research can guide you, but it can’t replace hard-won, personal experience.

The smartest approach is to experiment. Try different rep speeds, programs, and methods, and track how your body responds. Keep what works, discard what doesn’t, and learn from your victories and your mistakes.

That’s how you unlock your full potential—one tested and proven workout at a time.

References

1 – Krzysztofik M, Wilk M, Wojdała G, Gołaś A. Maximizing Muscle Hypertrophy: A Systematic Review of Advanced Resistance Training Techniques and Methods. Int J Environ Res Public Health. 2019 Dec 4;16(24):4897. doi: 10.3390/ijerph16244897. PMID: 31817252; PMCID: PMC6950543.

2 – McBride JM, Haines TL, Kirby TJ. Effect of loading on peak power of the bar, body, and system during power cleans, squats, and jump squats. J Sports Sci. 2011 Aug;29(11):1215-21. doi: 10.1080/02640414.2011.587444. Epub 2011 Jul 22. PMID: 21777152.

3 – Mangine GT, Hoffman JR, Wang R, Gonzalez AM, Townsend JR, Wells AJ, Jajtner AR, Beyer KS, Boone CH, Miramonti AA, LaMonica MB, Fukuda DH, Ratamess NA, Stout JR. Resistance training intensity and volume affect changes in the rate of force development in resistance-trained men. Eur J Appl Physiol. 2016 Dec;116(11-12):2367-2374. doi: 10.1007/s00421-016-3488-6. Epub 2016 Oct 15. PMID: 27744584.

4 – Schoenfeld BJ, Ratamess NA, Peterson MD, Contreras B, Sonmez GT, Alvar BA. Effects of different volume-equated resistance training loading strategies on muscular adaptations in well-trained men. J Strength Cond Res. 2014 Oct;28(10):2909-18. doi: 10.1519/JSC.0000000000000480. PMID: 24714538.

5 – Wilk M, Zajac A, Tufano JJ. The Influence of Movement Tempo During Resistance Training on Muscular Strength and Hypertrophy Responses: A Review. Sports Med. 2021 Aug;51(8):1629-1650. doi: 10.1007/s40279-021-01465-2. Epub 2021 May 27. PMID: 34043184; PMCID: PMC8310485.

6 – American College of Sports Medicine. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports Exerc. 2009 Mar;41(3):687-708. doi: 10.1249/MSS.0b013e3181915670. PMID: 19204579.

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