- "Repetitions vs. Time-Under-Tension"
- "Training Goals for a Beginner"


Ask anyone for a breakdown of their weight-training routine and they will say "X # of sets of X # of repetitions". BUT, 10 repetitions to one individual may be only 5 repetitions to another. Take a look at the speed of the person training next to you. Are the repetitions performed slowly and meticulously? Are the repetitions "piston-like" (up-down-up-down)? OR are the repetitions so fast that all you see is blur of limbs and dumbbells?

The various repetition cadences brings me to the topic of this column: muscle time under tension (TUT). "Time under tension" (TUT) refers to the time your muscles are actually working and TUT has become a hot topic amongst strength coaches and trainers. Most trainers will agree that TUT is important variable for muscle growth along with weight, # of sets, and # of reps but TUT is often a neglected variable. 

TUT is controlled by repetition TEMPO. The tempo refers to the speed of movement in the resistance exercise. The lift can be broken down into 4 phases: the eccentric, a "transition pause", the concentric, and a second "transition pause". The eccentric phase is muscle lengthening (i.e. lowering the bar in the bench press) while the concentric phase is muscle shortening (i.e. pulling the bar to the chest in the front pulldown). Most "transition pauses" should be eliminated from your training because often the muscle is allowed to rest at this point reducing the effectiveness of the exercise.

The designation of a slow tempo: 4 - 0 - 2 - 0 (4 seconds in the eccentric phase,

no pause, 2 seconds in the concentric phase, no pause, 4 second eccentric, etc.). The designation of an explosive tempo: 2 - 0 - X - 0 (2 seconds eccentric, no pause, an explosive concentric phase, no pause, etc.).

Now, prescribing 10 repetitions (without a consideration to tempo) to 2 different people could be like prescribing 2 totally different training programs all together. If "Jeremy Slow" does his reps with a tempo of 3 - 0 - 2 - 0 it will require a significantly lighter load than if "Fast Craiggy" did his reps with a 1 - 0 - 1 - 0 tempo. BUT/, most importantly, what would be the final outcome of such a difference in training?

Theoretically, using different movement speeds will elicit different neuro-muscular responses from the body. I.e.) A slow tempo will increase the time of tension in the muscle for each rep. If an equal number of repetitions are used with a fast tempo, the amount of work will be greater with a slow tempo. Therefore the slow tempo is associated with programs designed to enhance muscle size. 

A fast tempo is beneficial to sport-specific training and incorporates some explosive movements. Therefore, a fast tempo will train the neuromuscular system to contract at a faster rate BUT/ may not provide the optimal stimulus for muscle growth (hypertrophy). The fast tempo is much more specific to sport movements as few sport movements occur at a slow, controlled tempo.

A typical recommendation by most strength coaches for TUT is between 30-70 seconds for muscle growth (any more or less is presumed to be less efficient for growth). Sticking with the TUT recommendation may require a greater focus on exercise technique and a possible reduction in weight. To maintain a certain number of repetitions OR TUT the weight may need to be decreased. Do NOT sacrifice exercise form OR safety in order to maintain tempo as you approach failure. It is okay to have a long tempo in the concentric phase in the final repetitions of each set due to muscle failure.

The benefits of slow tempo

: increased TUT (when number of reps are equal)

: elimination of momentum (therefore more work done by the muscle in each repetition)

: possible reduction in injury risk

The benefits of fast tempo
  :specificity of training to sport performance

: ability to use a heavier weight (if momentum is minimized, this may compensate for the reduced TUT, because there is a greater level of tension)


Remember though, muscle growth can still occur if a set is less than the previously recommended TUT. For example, powerlifters train for maximal strength with very heavy weights and few repetitions (< 5) and still have a lot of muscle growth. On the other hand, training with lighter weights that allow a longer TUT will still help increase maximal strength levels. The longer TUT theoretically promotes more muscle growth, and more muscle is correlated with greater levels of strength. The fact is, no one knows exactly how muscle growth occurs in response to training.

The amount of tension on the muscle is probably a key component to growth. The magnitude of muscle tension is increased through lifting heavier weights and the volume of muscle tension is increased through increasing the length of which the tension is applied (TUT).

There you go. That is a lot of information on a previously neglected topic. Please keep in mind a lot of this information has only a theoretical basis and hopefully the issue will become clearer in the future.


In 2 recent studies, untrained males were placed on an 8-week resistance-training program (3-6 sessions per week training the entire body 2-3 times per week). The intensity was moderate to high (3 sets of 8-10 at 80-85% 1 RM) and the exercises were performed on machines. What kind of improvements did the subjects make? What should we tell the eager beginner resistance trainee to expect when they start lifting weights? Remember that the program was designed for hypertrophy and strength gains and not weight loss. Another important note to make is that the studies used machines! Therefore, any method of resistance is effective at increasing body mass in beginner trainers.


Lean body mass increased ~2-4kg

Body fat decreased ~2-4%

Strength increased ~14% (biceps curl) to 47% (leg curl)

The beginning trainer can expect some pretty dramatic increases in strength and changes in body composition, BUT/ remember that all good things must end as strength increases slow down over time. Note the changes in body composition, providing a pretty good reason to include resistance training in weight-control programs. 


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