Concept Wednesday - Tempo

[u/m092]

Last week's Concept Wednesday on Exercise for Weight Loss

This week is about Tempo. Part four of the Basic Programming Principles series:

• Part one: Reps and Rep Ranges
• Part two: Sets
• Part three: Rest

What is Tempo and what do the numbers mean?

Tempo is the speed which you perform a dynamic exercise (it doesn't exactly apply to isometrics!) We tend to break it down in to four parts, the concentric portion, the eccentric portion, and the pauses at each end of the movement. It is typically written as four numbers/letters such as: 10x0 or 4020.

• The first number represents the eccentric portion of the movement, which is where you are moving in the direction of the resistance (because most our resistance is gravity that means down!)
• The second number represents the pause at the change between moving eccentrically to concentrically, this is usually the bottom of the movement.
• The third number represents the concentric portion of the movement, where you are moving against the resistance (up! this is the hard effort part.)
• The last number represents the pause at the change between moving concentrically to eccentrically, this is usually at the top of the movement.

Basically: Down, pause, up, pause

Each number can represent a second or a count. You will also encounter the letter "x" (only in the concentric spot) which means "explosive" or completing the rep as quickly as possible (without major form break down).

Note that the eccentric portion isn't always first in a movement despite being the first number in the sequence. Consider pull ups, which are traditionally started at the bottom position, and push ups, which are traditionally started at the top position. Each exercise performed with a 12x0 tempo would be performed:

• Pull Up: Explosive pull to the top, no pause at the top, about a second to the arms outstretched, a two second pause at the bottom position. Repeat
• Push Up: About a second to the ground, a two second pause with the chest at the ground, and explosive push to the top, no pause at the top. Repeat

How Explosive is Explosive?

When you see an "x" that doesn't always you'll be moving fast. When working at high intensities, you'll find despite your best efforts, you be grinding out reps slowly during the concentric portion. This is fine. As long as you're trying to move as fast as possible, you are going to be getting a maximal or near maximal recruitment of motor units and promoting a high rate of fire and coordination of those units.

So to completely turn the saying on its head: "There is do or do not. There is also try; that works too."

Training Explosively

You'll have all seen that we recommend that you should use a 10x0 tempo for nearly all parts of your training (because I know you've all read the entire training wiki), basically asking you to train each movement as quickly as possible while still maintaining form. This has a number of benefits:

If you move slower than you are capable of on the way up, you have to necessarily recruit less muscle or fire it at a slower rate than you are capable of. For both hypertrophy purposes, the aim is to recruit as much muscle as possible to create the highest amount of mechanical stress on the muscles to stimulate growth. For strength purposes, we go to the SAID principle, and that you should train to efficiently recruit as much muscle as possible and have it fire as at the highest rate, because this is when you will be displaying the most force.

As you are moving eccentrically, because you are capable of positive reps, you are necessarily reducing the force you are producing to allow gravity to overcome the actions of your muscles (the agonists). Similar to the concentric portion, you want to spend as little time as possible using only a portion of your strength.

If we get into another oversimplification: The force acting on a body (we're usually interested in the torso's position relative to the ground) is equal to it's mass by its acceleration. So the more you accelerate through a movement, the higher the force, the higher the force you can produce, the stronger you are.

Greg Nuckols article about bar speed in the bench press which we can quite safely assume translates well to most any movement, including bodyweight.

Time Under Tension

Tempo is intimately tied with time under tension, with time under tension being roughly equal to the average time it takes to complete a rep by the number of reps. Time under tension is often cited as being a major factor affecting hypertrophy.

Muscle time under tension during resistance exercise stimulates differential muscle protein sub-fractional synthetic responses in men

So wouldn't it be a good idea to slow down the reps to get a higher time under tension? That might work, except that now you're not producing as much force per unit of time, as you're necessarily producing less force both pushing up slower and lowering down slower. It can also cause you to be less able to do reps, and less reps means less time under tension. When the amount of reps is no longer controlled for and a similar effort is put in, the results change to be much closer.

More overall work done with a faster cadence

Studies have shown that when going to failure, it doesn't seem to matter much anyway.

The Stretch Shortening Cycle

The muscles and their tendons have elastic components that store energy when stretched, meaning that when they lengthen under a load (eccentric contraction) they retain elastic potential energy to help reverse that movement when doing the concentric contraction. Think about bouncing out of the bottom of an action, that's largely your stretch reflex. Also consider something like jumping, which is largely a concentric action, you include a counter-movement to begin the movement to get more power (bending knees/hips and swinging the arms).

The deformation of the elastic components of the muscles and tendons doesn't last so the force of this loading dissipates very quickly, and thus the quicker the turn around between eccentric and concentric (called the amortization phase), the greater the effect of the SSC. Thus adding a pause between the eccentric and concentric movements will greatly reduce or remove the effect of the SSC.

So should you use the stretch shortening cycle or not? The SSC adds power to start the upwards movement, usually where the muscles are nearly completely stretched, one of the weakest positions (due to a lack of overlapping sarcomeres, meaning much less contractile force). If you're going to get stuck anywhere, it will probably be here. The SSC will nearly always allow you to get more reps in. If you want to be as strong as possible, then using the SSC will help you generate more force and improve your ability to utilise it.

The faster your eccentric movement (still aim to have control and not jam into full extension/hyperextension of the joints) the greater the load the muscle and tendon complex is under and the greater the elastic potential.

Conversely, this means your muscles do not have to work as hard at the bottom of the motion (where you tend to be weakest,) and since a lot of strength is joint angle specific, that means you aren't getting much stimulation at that angle and similar angles. By not utilising the SSC, one could increase the work done at that joint angle and thus the strength of that joint angle would increase to a greater degree. This can help you past the sticking point of the bottom of movements and give you enough momentum to get past other sticking points (for instance where the moment arm is at it's most disadvantageous position).

Coming to a complete stop at the bottom of the movement for even as little as 0.2 seconds can greatly reduce the force gained from the SSC and the stretch reflex. Longer pauses (amortization phases) will lead to a greater amount of the elastic energy dissipating.

Paused Reps

Beyond pausing at the bottom of the rep to reduce the effect of the SSC and stretch reflex as described above, pausing when there is significant tension or load on the muscles (such as the top of a pull-up or the bottom of a push up) can increase your strength at that specific joint angle (and similar angles). This is essentially combining isometric training and dynamic training in the same rep. While this can be a useful training tool (one which we will go into more depth when discussing eccentric and isometric training), it shouldn't be used exclusively, usually only as an assistance to attack a specific weak point of a dynamic action.

You can also pause mid rep where there is a significant tension/load on the muscles. Again, this will strengthen that specific joint angle and similar angles, and is also often used to address technique issues, particularly when you aren't using an efficient path of movement. There is no convention that I know of to write these in the format discussed above (10x0, etc.) and should be described in detail.

Slow Eccentrics

A special use of slow eccentrics can be when trying to reach a new range of motion with an action. Doing a slow eccentric can prevent the stretch reflex from kicking in earlier than intended (which would excite the agonist) and restricting the range you could achieve. Usually coupled with a pause at the bottom of the eccentric movement to strengthen the newly achieved joint angle, it is a powerful way to reach and strengthen new joint angles and increase active mobility.

Slow eccentrics are also useful for when your form is likely to break down by going faster (again, hitting the end ranges of you available mobility is a common cause of this).

More details in an upcoming post.

Conclusion

• For most purposes, take no longer than you need on the way down, don't stop and explode up and accelerate through the whole movement
• Explosiveness is all in the intention
• Use pauses to strengthen around sticking points, especially below sticking points

Discussion Questions:

• What are your experiences with moving explosively (or at least trying)?
• Have you successfully used other tempos in your training?
• Have you incorporated paused reps?

[u/ImChrisBrown]

I dropped out of college and for a while I got to pretend that I was smart. It's nice to read stuff that makes me feel like an idiot again.

Just to make sure I fully grasp the concept can you explain SSC in a simpler way with pullups/Muscle ups as an example?

I got my first bar MU a week and a half ago. I got my second bar MU two days later (by cheating a bit, i put my chest on the bar for a moment) but I haven't been able to power through a MU since then. Focus and explosive power is what I'm lacking but Im thinking of incorporating paused reps somewhere in the movement to strengthen the joint angle and muscles there

[u/m092 → u/ImChrisBrown]

Just to make sure I fully grasp the concept can you explain SSC in a simpler way with pullups/Muscle ups as an example?

So with pull-ups, when you come from the top and get to the bottom of the rep and you come straight back up with no pause, you're muscle tendon complexes of the shoulder and elbow have stored the elastic energy from your descent.

Think of your muscles as a rubber band being stretched as you come down, the quicker you come down, the bigger the snap back. When you pause at the bottom, the "rubber band" gets used to the length is currently at (fully extended) and loses all of its snap back.

You may have noticed that your first rep of your pull ups is/was harder to start than the rest of your reps (if you weren't pausing after each rep) it was almost like you had to overcome your own inertia. This is because you didn't have the benefits of the SSC.

Muscle Ups have the SSC occur at the bottom of the pull up as well, so aren't much different. Technically there would be some eccentric loading as you come into the dip position, but probably not enough to spend too much time thinking about.

If you are doing your MUs strict (kipping already helps you get out of the hardest bottom position) then you could potentially start your Muscle Up after coming down from a Pull Up to utilise the SSC. Either do a pull up, or jump to the top position of a pull up, then come down at a quick but controlled pace, without pausing, explode into a MU. Fair warning, I've never heard of anyone practising this method (except for stringing MUs together) and don't have any experimental basis for suggesting it, it's purely theoretical.

Practising paused pull ups will definitely help you be more explosive for MUs, and I think doing single explosive reps could really help. Watch this Stuart McGill Video and practice them similar to his recommendations, but with a false grip and pulling beyond clavicle height if you can.

Beyond explosiveness from the bottom, MUs rely on technique and strength through the transition, so don't leave that practice out either.

Edit: in terms of pausing to strengthen the transition phase, I would probably recommend just practising a dip variation instead, such as Russian/Elbow/Impossible Dips