If you haven’t noticed by now, rep speed has become a bit of a fascination among the gym bros of the world. A lot of debate exists over how fast you should complete your reps. Ask a powerlifter or weightlifter and they’ll probably say you should lift as fast as possible. However, a bodybuilder will probably say you should slow down and “feel” the reps. Of these two opinions, which one is correct? Well it really depends on the goal of the movement. You probably wouldn’t want to intentionally try hitting a 1RM clean and jerk with a slow rep speed. But certainly there are times when going slow has its advantages.
Regardless of whether you are trying to bring about some enhanced response, shouldn’t you be mindful of the cadence you use when you complete an exercise? So much attention is paid to other aspects of lifting (number of reps, weight on the bar, etc.) that most people forget tempo is a variable we can use as well. But how can we use tempo to our advantage and what can we expect to gain from it? Much of the fuss around tempo is focused on its potential benefits for hypertrophy. However, you’ll find that tempo has much more to offer outside of hypertrophy alone.
Does Increased TUT = Increased Gains?
Many bodybuilders have sworn by the principle of time under tension (TUT) as a key to muscle hypertrophy. The logic is pretty sound on this one. The more mechanical tension you apply to the working muscle, the greater the response with respect to muscle growth. By using a tempo that emphasizes the time under tension, you would theoretically increase the muscle building potential of the exercise.
One study found that increasing the time spent lifting a submaximal weight led to significantly greater muscle protein synthesis compared to lifting the same weight with a faster tempo [2]. This makes sense though because the weight stayed the same for both conditions and the same number of reps were completed with the slow tempo being taken to failure. They simply did more work in the slow condition compared to the fast. However, another study found that fast velocity rep speed may be more effective than slow velocity reps when volume is equated [6].
For the most part, it seems that increased time under tension doesn’t necessarily mean that you glean more benefit. It seems to come down to a matter of volume. Although the slower velocity allows you to apply more time under tension to the working muscle, the load has to be lower in order to compensate. This reduction in weight negatively impacts the total volume of the exercise, which seems to negate some of the potential hypertrophic benefit.
Even the prospect of activating more muscle fibers seems to be lost on TUT. The mind muscle connection that the bros advocate so strongly for may not make much of a difference when it comes to motor unit recruitment. There are two ways to recruit a higher order motor unit (the type II muscle fibers): expose the muscle to heavy weights, or cause enough fatigue in the lower order units to force activation of the higher ones. Increased TUT plays on strategy number two. However, it seems that higher velocity or heavier reps actually tend to recruit more muscle fibers than slower muscle contractions [3][7].
Tempo: What is it Good for?
So it seems that modifying tempo to increase time under tension doesn’t necessarily give you an advantage in the strength and hypertrophy realm. However, that doesn’t mean you should forget about it altogether. There are still a few areas that tempo could add value:
Connective Tissue Integrity
Tempo training may not have magical muscle hypertrophy benefits, but when it comes to the strength of our tendons and ligaments, it can be very useful. Studies have shown that deliberate rep speed prescriptions are phenomenal for the rehab process of injuries such as muscle strains or tendinopathy. Specifically, eccentric action of injured tissue has been shown to activate genes related to connective tissue repair [4]. Furthermore, heavy, slow resistance training has been shown to improve tissue healing, integrity, and pain related to muscle and connective tissue injury [1]. In fact, heavy, slow resistance training was even more effective than standard rehab protocols and corticosteroid injections in improving outcomes of tissue injury [5].
This improvement in tissue quality is one of the major benefits of including longer tempo work in your routine whether you are injured or not. Building a solid foundation within the tissues that surround your muscles is never a bad idea. Doing so will allow you to handle heavier weights with less risk of injury or pain.
Prepping the Nervous System
Similar to how deliberate tempo work can help build connective tissue integrity, it can also help to prime your nervous system for more explosive work. You need to learn how to decelerate and control force before you can fully produce it. Think of the way you might learn to handle an 800 horsepower sports car. You are going to spend time going slow and figuring out the nuances of the car before you put the pedal to the metal. The same strategy applies to prepping your CNS for heavy explosive exercise.
Taking the time to control the movement and “go slow” with each rep allows your nervous system to learn the pattern well. It builds strength in all areas of the strength curve and allows you to push through sticking points once you do actually load up the bar and unleash the beast. Don’t just take it from me though. Numerous strength coaches have employed the Triphasic Training approach with their collegiate and professional athletes with great success. We can thank Mr. Cal Dietz for bringing this style of training to the masses.
Movement Variety and Progressive Overload
When it comes down to it, you have to make sure your training is fun and stimulating in order to make continual progress. And to that point, there are only so many ways we can vary our set and rep schemes before we get bored. Incorporating a different tempo into even the most basic movements makes them that much more versatile. For instance, let’s say regular old squats just aren’t packing as much of a punch as they once did. Applying a four second eccentric or a three second pause provides a novel stimulus that allows you to keep making progress. This adds yet another layer of training variables you can actively manipulate.
Additionally, this provides a nice alternative to the heavy work that might beat you up from time to time. We saw from the studies mentioned earlier that slower reps (higher TUT) does lead to increased muscle fiber recruitment and muscle protein synthesis compared to faster reps at the same load. Although it may not match the stimulus of heavier movements, it certainly provides a good benefit above traditional rep speeds.
Conclusion
It seems that tempo work has been misclassified as an outcast training variable simply because of the research that has been done on hypertrophy. The literature seems to agree that it doesn’t necessarily provide an additional hypertrophic benefit like the gym bros claim. However, it is always useful to look at something from a different angle to assess its worth. Toe to toe, it may be as good, or is perhaps slightly less effective compared to heavier or more traditional reps (no tempo). But if it helps you to keep your training fun and challenging, then it does have value as a training variable. Add to that the undeniable benefits to connective tissue health and nervous system polarization, and you have a pretty darn useful tool in the toolbox. Try using some tempo variation in your own training and I’m sure you’ll agree!
References
- Beyer, R., Kongsgaard, M., Hougs Kjær, B., Øhlenschlæger, T., Kjær, M., & Magnusson, S. P. (2015). Heavy slow resistance versus eccentric training as treatment for Achilles tendinopathy: a randomized controlled trial. The American journal of sports medicine, 43(7), 1704-1711.
- Burd, N. A., Andrews, R. J., West, D. W., Little, J. P., Cochran, A. J., Hector, A. J., … & Phillips, S. M. (2012). Muscle time under tension during resistance exercise stimulates differential muscle protein sub‐fractional synthetic responses in men. The Journal of physiology, 590(2), 351-362.
- Hatzel, B., Glass, S. C., Johnson, S., & Sjoquist, H. (2013). Effects of Lift Velocity on Muscle Activation During Leg Extension.
- Hyldahl, R. D., Nelson, B., Xin, L., Welling, T., Groscost, L., Hubal, M. J., … & Parcell, A. C. (2015). Extracellular matrix remodeling and its contribution to protective adaptation following lengthening contractions in human muscle. The FASEB Journal, 29(7), 2894-2904.
- Kongsgaard, M., Kovanen, V., Aagaard, P., Doessing, S., Hansen, P., Laursen, A. H., … & Magnusson, S. P. (2009). Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. Scandinavian journal of medicine & science in sports, 19(6), 790-802.
- Mohamad, N. I., Cronin, J. B., & Nosaka, K. K. (2012). Difference in kinematics and kinetics between high-and low-velocity resistance loading equated by volume: implications for hypertrophy training. The Journal of Strength & Conditioning Research, 26(1), 269-275.
- Sakamoto, A., & Sinclair, P. J. (2012). Muscle activations under varying lifting speeds and intensities during bench press. European journal of applied physiology, 112(3), 1015-1025.
