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If your client's goals include muscle gains, then you may have heard of time under tension (TUT) training. Also known as "tempo training" or "super-slow training," TUT training focuses on manipulating rep speed during resistance training. This article will take a closer look at this type of training, break apart its components, determine just how effective it is based on the research, and then help you decide if this is the best type of training for your clients.
The term, "time under tension" or TUT for short, refers to the amount of time your muscles are under a load during resistance training. Track this time by monitoring repetition tempo which is simply rep speed. Tempo is tracked by noting the time it takes for a muscle to contract during each phase of the muscle action spectrum. There are three main types of muscle contractions:
A muscle produces tension during each type of contraction. The difference is in the length of the muscle during activation. In an eccentric contraction, a muscle lengthens as it produces tension so it can slow down a movement. There is no length change during an isometric contraction, but tension is still produced to stabilize the body during a movement. During a concentric contraction, the muscle shortens as it speeds up a movement.
Tempo is typically represented by three numbers written in the following way:
The first number is the time spent in the eccentric phase of a movement, the second number is the isometric phase, and the third number is the concentric phase. For example, during a loaded barbell squat exercise, the first part of the exercise is the eccentric which occurs as you lower the weight. Any pause before pushing the weight back up is called the isometric phase of the exercise. Finally, the concentric phase occurs as you push the barbell back up to starting position.
A programming template following a 2/1/2 tempo means the client is taking two seconds to lower the weight, pauses for one second, and then is spending about two seconds to push the barbell back up to the starting position. In this scenario, the total time under tension is five seconds (2+1+2=5) just for one repetition. Using the 2/1/2 tempo, 10 repetitions in a set means 50 seconds of time under tension for that set.
Research is mixed in terms of muscle growth. Many proponents of TUT training focus on the results from a study done in 2012 which suggest that TUT leads to muscle gain (1). However, there are also studies discouraging the need to rely on TUT (2,3). For this reason and others, it's best not to take TUT training as a gold standard. TUT training is an alternative way of training which deserves consideration but, all the principles of training still need to be considered such as the Overload, SAID, and Specificity principles.
There are a variety of ways to implement TUT training. Add a cycle of TUT training to a linear periodization plan to help break a plateau or incorporate to a weekly undulating periodization plan to -keep clients interested. A weekly undulating periodization plan lets your client's train for different adaptations within the same training cycle.
Another possibility is mixing in a combination of shorter tempos to exercises with higher loads (e.g., compound exercises) along with longer tempos for exercises used with lighter loads such as with single-joint exercises like a biceps curl. Including lifting techniques, such as drop-sets or forced reps, can increase TUT during a training session as well. With the help of a spotter, forced reps let your client push through the point of relative failure, known as the sticking point, and prolong the amount of time under tension.
Ultimately, choose the set-up that works best for your client's preferences and their goals. Accumulate enough volume to increase strength and add muscle.
To build muscle, follow traditional recommendations that range between 20 to 70 seconds (4, 5). The tempos for strength and endurance lay somewhere in between.
Strength - Less than or equal to 20 seconds
Hypertrophy - 20 to 70 seconds
Endurance - Greater than or equal to 70 seconds
To put it all together, incorporate general TUT guidelines into a simple programming template. For the other variables, the variables that are most likely to achieve muscle growth involve a set range of 3-5, a range of reps that range between 6-12, and a load that creates an intensity of 67 to 85% of the clients possible one rep max. In theory, this is should help with maximizing hypertrophy.
Lost yet? Basically, any combination of repetition tempos that range between 2/0/2 and 3/2/1 is moderate enough to allow a high enough rep number to permit a total volume that promotes muscle growth. It does take some math, so keep the training program as simple as possible to start. Using these parameters, a leg program that focuses on the glutes could look like this:
Leg Day (Glute Focus)
Don't go and buy a metronome just yet. Keep in mind that tempo isn't the only variable affecting muscle growth. There are other variables that should also be carefully selected.
First, consider the total amount of tension a muscle group experiences during an entire training session. Progressive overload helps your muscles to adapt and increase the number and size of those muscle fibers. So, adjust the volume of your client's programming template as needed.
Second, is the degree of tension produced by each muscle when lifting. To better understand this one, think of the tension produced in the muscle as mechanical tension. Mechanical tension develops within the muscle as its corresponding joint moves to produce an action such as a biceps curl. It has to do with the activation produced in a muscle during a movement when moving a weight.
So, curling a heavy weight creates more tension in the biceps muscle than doing so with a light weight. This means that a rep performed at a client's one rep max is different from a rep performed at 50% of a client's one rep max. Also, super-slow lifting speeds are not likely to promote huge gains. The sets that last too long are going to limit the amount of weight lifted. This is one of the reasons recommendations for muscle growth include more moderate variable ranges.
In contrast, a client with muscle imbalances or poor form needs to perform at slower rep speeds and with lighter weight to achieve an increased degree of tension before moving on to heavier lifting and an increased number of sets.
Depending on your client's needs and fitness goals, manipulate repetition tempo to achieve a specific adaptation. Slower rep speeds and higher repetitions are best to develop stability and muscle endurance. This type of training is best for novice clients or those recovering from injuries who are looking to create neurological adaptations in preparation for more advanced training. For example, spending more time in the eccentric phase of an exercise which targets the hamstrings is effective in rehabilitation from a strain and is beneficial for injury prevention (6). Once your client is ready, progress to more sets, move on to moderate rep speeds and slightly fewer repetitions to increase the loads. This will help to maximize volume for better strength and muscle gains.
The great thing about TUT training is its versatility. Use it with a variety of populations depending on the goals of the client. It isn't just for those looking to gain muscle. It can be a great way to train those new to exercise or clients who struggle to activate a specific muscle group, such as those with gluteal amnesia (e.g., sleepy glutes). These clients will benefit greatly from decreasing their rep speed to maximize neural activation (think mind-muscle connection). TUT training also works for clients who keep getting injured or those coming off an injury. By adjusting the rep, set, intensity, and tempo ranges, as well as rest intervals, a client can avoid overtraining and focus on better form to progress their training.
If you are interested in learning more about bodybuilding methods and traditions, check out the ISSA's Bodybuilding Specialist course.
Burd NA, Andrews RJ, West DW, et al. Muscle time under tension during resistance exercise stimulates differential muscle protein sub-fractional synthetic responses in men. The Journal of Physiology. 2012;590(2):351-362. doi:10.1113/jphysiol.2011.221200.
Mangine GT, Hoffman JR, Gonzalez AM, et al. The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men. Physiological Reports. 2015;3(8).
Mitchell CJ, Churchward-Venne TA, West DWD, et al. Resistance exercise load does not determine training-mediated hypertrophic gains in young men. Journal of Applied Physiology. 2012:113(1):71-77.
Stone MH, O'Bryant H, Garhammer H. A hypothetical model for strength training. Journal of Sports Medicine and Physical Fitness. 1981;21:341-52.
Kraemer WJ, Adams K, Cafarelli E, et al. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Medicine and Science in Sports and Exercise. 2002;34(2):364-80.
Comfort P, Green CM, Matthews M. Training Considerations after Hamstring Injury in Athletes. Strength and Conditioning Journal. 2009:31(1):68-74.
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