Time under tension is critical to muscular development. Do you lift quick or do you lift slow? What’s more beneficial for building muscle? The time under tension you place on your muscles during training has a profound affect on their growth.
Time Under Tension
Time under tension (TUT) can be defined as the total time at which your muscles are placed under force during a repetition (rep) and/or set. A rep has three phases:
Concentric: The shortening/flexing/contracting of a muscle e.g the shortening/flexing/contraction of a bicep when you bend your elbow or when the weight is being lifted – bicep curl
Pause: Holding maximal contraction of the muscle being worked (if applicable)
Eccentric: The lengthening/stretching/relaxing of a muscle e.g the lengthening/stretching/relaxation of the bicep when your arm is straight or when the weight is being lowered
Time under tension refers to the total time at which you contract the muscle, the pause at full contraction (if any), and the time stretching/relaxing the muscle.
For example: If we were to perform a set of 10 reps with a 4 sec rep time (2:0:2), the total time under tension is 40 secs. If we were to add a pause of 1 sec into the set (2:1:2), the total time under tension is now 50 secs.
But what does this mean!?…
We work the muscle harder by forcing it to work for longer without having to increase weight or reps, thus encouraging the growth of new muscle (especially if this is a whole new force being applied)!
The Science of Time Under Tension
A 2012 study published in the Journal of Physiology studied the effects of increased time under tension on protein synthesis – the creation of protein from amino acids in a cell which is essential for building muscle.
The study comprised of eight males training legs twice per week for two years with three sets of single-leg extensions at thirty percent of their one rep max. On one leg, the participants performed six second concentric and six second eccentric repetitions to failure, and on the other leg, one second concentric and one second eccentric repetitions to failure.
Biopsies of muscle tissue from both legs were then taken at six, and twenty four to thirty hour intervals post exercise. The results of protein synthesis were amazing to say the least.
These results suggest that loading the muscle for an increased time under tension may lead to not only a faster affect, but also an increase of protein synthesis on muscle, thus leading to improved muscular development.
Building Muscle Takes Time
Time under tension has a direct correlation on protein synthesis, placing more importance on rep speed for building muscle.
After years of research and experiential learning, world class strength and conditioning coach Charles Poliquin suggests a TUT of 30-70 secs for hypertrophy & strength.
Poliquin suggest a TUT of 30-50 secs per set for size and strength (functional hypertrophy) and 50-70 secs TUT for strict hypertrophy.
- Time under tension or rep speed is important to muscular development
- Slow, controlled reps builds muscle faster than fast reps
- The longer the muscle is placed under the tension, the better the affect of protein synthesis leading to improved muscular growth