In this article featuring proper “rep tempo” or “rep timing” for your maximum gains, you’ll find more information about time under tension, the speed at which you should move the weight through each leg of each repetition, and more.

Time under tension

The most popular schools of thought is using very slow reps to maximize “time under tension” thus muscle growth. “Your muscles don’t know weight,” many bodybuilders say, sounding almost philosophical, “they only know tension, and that’s what stimulates growth.”

Well, like many “weird little moves” in the fitness space — you know, the ones that are supposed to instantly increase your bench press or melt away belly fat — time under tension isn’t important enough to warrant special attention and simply; There is a by-product of proper training that can be more or less ignored.

You see, the more slowly you perform the reps with a given weight, the fewer reps you can perform with it. Depending on how slow you go, you may get half the reps or even less as a normal rep pace. ¹

As you reduce the number of reps you perform, you also reduce the total work done by the muscle, and as you reduce the amount of work done, you increase muscle building and strength building potential of the exercise. ^{2 3}

The question is whether the “trade off” of time under stress for total work is worth it. Does increasing time under tension lead to decreased performance and result in greater strength and muscle growth?

Research says no

Research says no, for example:

A study by scientists at the University of Sydney found that subjects after traditional “fast” training on the bench press gained more strength than after slow training. ⁴

A study by researchers at the University of Connecticut found that training at a much slower pace than at a normal, self-regulated tempo resulted in lower levels of peak force and power. ²

A study by scientists at the University of Wisconsin found that even in untrained individuals, a traditional training tempo resulted in greater strength in the squat and greater power in the countermovement jump. ⁵

A study by researchers at the University of Oklahoma found that four weeks of traditional resistance training was more effective at increasing strength than super-slow training. ⁶

These findings aren’t exactly surprising, given the underlying mechanics of muscle growth and how dependent it is on building strength; if you want big muscles, you have to get strong.

Fast Rep-tempo and slow rep-tempo

Researchers from Ithaca College, who compared fast-paced bench pressing to slow-paced:

• One-way repeated measures analysis of variance showed tempo with a faster eccentric phase (1-second), and no lower rest significantly increased (p ≤ 0.05) power output (PO) and slower eccentric velocity (4-second) repetitions or a much lower rest (4-second) than the tempo with.
• This combination of more repetition and PO resulted in a higher amount of work. The varying repetition rest (1- or 4-second) did not significantly affect PO or repetitions.
• The results of this study support the use of faster eccentric speeds and no lower rest during acute performance testing to maximize PO and number of repetitions during a set of bench press. ⁷

It’s also worth noting that when I didn’t know what I was doing, I used a very slow setting to maximize the tension time, and my results were consistent with the research. I didn’t find it any more effective than my regular training routines, which were pretty crappy indeed.

How to perform “Rep Timing”?

The rep timing I recommend is either “2-1-2” or “2-1-1” timing. This means that the first part of the rep should take about 2-seconds, followed by a 1-second (or less) pause, followed by the last part of the rep, which should be followed by 1- and 2-second to perform. ⁸

For example, if you apply “2-1-2-0” to the bench press, you’ll perform like this:

1. The first digit (2) is always the eccentric (“lower” or “negative”) part of your lift. In a bench press, you will bring the bar down to your chest for a count of 2-second.
2. The second digit (1) represents the mid-point of your lift. Again, in the bench press, you’ll hold the bar at your chest for 1-second before pressing.
3. The third digit (2) will then be the concentric (‘lifting’ or ‘positive’) part of your lift. This would be to press the bar to your chest for a count of 2-second.
4. The fourth digit (0), which will not always be used, represents the time at the top of your lift. When there is no fourth number, or in this case with a 0, no time is spent at the top of your lift.

1. Headley SA, Henry K, Nindl BC, Thompson BA, Kraemer WJ, Jones MT. Effects of lifting tempo on one repetition maximum and hormonal responses to a bench press protocol. J Strength Cond Res. 2011 Feb;25(2):406-13. doi: 10.1519/JSC.0b013e3181bf053b. PMID: 20351575.[↩]
2. Hatfield DL, Kraemer WJ, Spiering BA, Häkkinen K, Volek JS, Shimano T, Spreuwenberg LP, Silvestre R, Vingren JL, Fragala MS, Gómez AL, Fleck SJ, Newton RU, Maresh CM. The impact of velocity of movement on performance factors in resistance exercise. J Strength Cond Res. 2006 Nov;20(4):760-6. doi: 10.1519/R-155552.1. PMID: 17194227.[↩][↩]
3. Goldberg AL, Etlinger JD, Goldspink DF, Jablecki C. Mechanism of work-induced hypertrophy of skeletal muscle. Med Sci Sports. 1975 Fall;7(3):185-98. PMID: 128681.[↩]
4. Munn J, Herbert RD, Hancock MJ, Gandevia SC. Resistance training for strength: effect of number of sets and contraction speed. Med Sci Sports Exerc. 2005 Sep;37(9):1622-6. doi: 10.1249/01.mss.0000177583.41245.f8. PMID: 16177617.[↩]
5. Neils CM, Udermann BE, Brice GA, Winchester JB, McGuigan MR. Influence of contraction velocity in untrained individuals over the initial early phase of resistance training. J Strength Cond Res. 2005 Nov;19(4):883-7. doi: 10.1519/R-15794.1. PMID: 16287371.[↩]
6. Kim E, Dear A, Ferguson SL, Seo D, Bemben MG. Effects of 4 weeks of traditional resistance training vs. superslow strength training on early phase adaptations in strength, flexibility, and aerobic capacity in college-aged women. J Strength Cond Res. 2011 Nov;25(11):3006-13. doi: 10.1519/JSC.0b013e318212e3a2. PMID: 21993022.[↩]
7. Pryor RR, Sforzo GA, King DL. Optimizing power output by varying repetition tempo. J Strength Cond Res. 2011 Nov;25(11):3029-34. doi: 10.1519/JSC.0b013e31820f50cb. PMID: 21881531.[↩]
8. Source: Bigger Leaner Stronger: The Simple Science of Building the Ultimate Male Body. By Michael Matthews. Available here: https://amzn.to/3S7dyYD[↩]