Muscular Development and Lifting Speed

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Your metabolism is your most precious asset when it comes to weight loss and fat loss. Your metabolism comprises all the chemical reactions in the body involved in maintaining the living state of the organism.

When your metabolism is elevated various cells in your body receive the message to do more of what they do. Depending on which cells receive this message this can translate into your hair growing faster, your nails growing faster, your muscle cells to increase their rate of repair and growth and so on. All this extra activity in the body requires energy, hence when you have an elevated metabolism you burn more energy which makes it easier to burn more fat as a fuel source and to lose body weight.

Size Matters

The first thing to understand is the size principle, which relates to the order of muscle fibre recruitment. You may have heard of slow twitch muscle fibres (type I) and fast twitch muscle fibres (type II). Type I fibres are the smallest and have high endurance and low force output, and type II fibres are the largest and have low endurance and high force output. There are actually several subdivisions of these fibre types.

I → IC → IIC → IIAC → IIA → IIAX → IIX

Muscle fibres are grouped into bundles called motor units. Each motor unit has one nerve cell (motor neuron), which activates it. At the smallest end you have low threshold motor units comprised of a small motor neuron and a small number of slow twitch muscle fibres with low force output but high endurance. At the largest end you have high threshold motor units comprised of a large motor neuron and a large number of fast twitch muscle fibres with high force output and low endurance.

Fast twitch muscle fibres are the thickest in diameter and have the greatest potential for growth.

For a light activity requiring fine coordination and motor control and high endurance, such as writing with a pencil, the body recruits the low threshold motor units containing the smallest fibres. As more force is needed, the body will recruit gradually larger and larger muscle fibres.

Lifting speed will affect the motor units that are recruited. Since lifting fast and explosively requires more force, your body will recruit higher threshold motor units, and hence a larger number of larger muscle fibres if you lift a given weight more quickly.

Surely that means that the best lifting speed for muscle development is to lift fast? Not so fast! (Sorry couldn’t resist.)
 
To achieve further muscle growth we must apply progressive overload to our workouts
 
Mechanisms of Hypertrophy

The next thing we need to remind ourselves of is the 3 mechanisms for hypertrophy as defined by Brad Schoenfeld.

1. Tension

The most important factor in muscle development is tension. Tension on the muscle stimulates mechanotransduction. This simply means that mechanical stimulus triggers a certain type of chemical activity – in this instance it triggers the anabolic pathways. More tension leads to a greater anabolic stimulus – up to a certain point. Beyond a certain threshold it actually becomes counter productive.

2. Muscle Damage

The activity of lifting weights causes microtrauma – microscopic damage to the muscle fibres. This damage causes localised inflammation. This ‘useful’ inflammation activates the release of growth factors involved in muscle development. To achieve further muscle growth we must apply progressive overload to our workouts, so that (throughout the course of a number of training cycles) the muscles are required to do more work, experience more damage and continue to adapt.

Slowing down your eccentric contractions (lower phase of a lift) as well as increasing the volume of your workouts will both increase muscle damage and stimulate greater development – up to a point. There is only so much damage your body has the capacity to repair and recover from and still continue to develop.

3. Metabolic Stress

Exhaustive exercise increases the build up of by-products of metabolism called metabolites (which include lactate, hydrogen ions, and inorganic phosphate). The build up of these metabolites indirectly mediates cell signalling. Some scientists believe this is due to cell swelling. You’ll experience cell swelling when you get a pump in the gym. The prevailing theory is that this swelling triggers a self preservation mechanism within the cell which causes it to get bigger and stronger.

Recognise that these three mechanisms of hypertrophy do not operate in isolation. However, to a certain degree we can preferentially target one over the others.
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Mechanisms of Hypertrophy and Lifting Speed

So let’s consider each of these mechanisms from the perspective of lifting speed:

Tension

On face value it would appear that lifting faster is the best option for muscular development, since it will increase tension, and therefore increase the anabolic stimulus. However, this is not the complete picture.

When you lift explosively there will be a rapid increase in tension at a certain point of the lift. Let’s consider the bench press. If you press as explosively as possible you get a massive increase in tension in the muscle fibres of the chest during the first few inches of the lift. Even if you continue to accelerate as explosively as possible, the momentum the bar is carrying during the second half of the lift naturally means there will be less tension in the muscle.

Your body will recruit different muscle fibres within a muscle at different parts of the joint angle. So if we lift a moderate weight explosively we increase tension in the bottom half of the lift but lose tension in the top half of the lift.

One solution is to lift a weight that is heavy enough that even at max effort, it still moves relatively slowly. It is the nervous system’s intention to lift explosively and apply more force which controls the size principle.

Another solution is to use bands or chains, which will increase the resistance as your mechanical advantage increases during pressing movements. However, this will not work for upper body pulling movements since the increase in resistance from either chains or bands comes on during the hardest point of the lift and defeats the purpose with these types of movements.

Also, you’ll see plenty of people in the gym performing the eccentric phase of their lifts very quickly – meaning that as they lower the weight, they are simply allowing it to free fall with gravity, rather than keeping the muscle under tension. Performing the eccentric phase in a smooth and controlled manner will contribute to maximising muscle tension for a given weight.

Earn the Right

One of the most important factors to consider is establishing and maintaining adequate tension in the target muscle groups for the full duration of a set. And then, as your training age increases, learning to generate even greater degrees of muscle tension as your skill and neuromuscular control improves. If you ask your average gym ‘bro’ to perform the bench press explosively, chances are he’ll get plenty of tension in his delts and triceps but barely any in his chest, because he hasn’t developed the technique and neuromuscular control to establish or maintain tension in his chest. If you want to incorporate fast lifting into a workout you have to earn the right to lift quickly.

You can increase muscle tension in one of three ways. You can consciously squeeze a muscle, you can lift a heavier weight, and you can lift explosively. But you must first learn to squeeze the target muscles before you add weight and before you increase lifting speed.

A lot of trainees are so anxious to apply progressive overload that they sacrifice form and muscle tension in the target muscle for extra weight.

Let’s consider two seemingly identical workouts:

Let’s say that a lifter performs 4 sets of 8 reps on a 3010 tempo with 60 seconds rest. Let’s say that the following week he puts exactly the same numbers down – same weight, reps, sets, tempo and rest. However, the second week he is consciously squeezing the target muscle group as hard as he can through the full duration of every rep and every set. Has he applied progressive overload? Yes! Even though it doesn’t show on his log sheets, he worked harder and created more tension in the second workout, and a better stimulus for adaptation.

So first and foremost learn to connect with and squeeze a muscle first. Then only add weight to the bar if you can maintain form and muscle tension IN THE CORRECT MUSCLE GROUP. And then finally, if you decide you want to incorporate fast lifting into your programme, gradually increase lifting speed whilst ensure that you maintain form and tension again.
 
If you want to incorporate fast lifting into a workout you have to earn the right to lift quickly
 
Muscle Damage

Muscle damage is generally maximised by increasing time under tension. This is generally pursued in two main ways – slowing doing the eccentric phase of the lift, or increasing volume.

For example 3 sets of 8 reps on a 5010 tempo is the same time under tension as 6 sets of 8 on a 2010 tempo (144 seconds).

However, you will only generate muscle fibre damage, and hence adaptation, in the fibres that are actually recruited. So once again lifting speed as well as load matter in this regard, since you will only create damage in the high threshold motor units if you lift heavy enough, or fast enough to actually recruit them.

Metabolic Stress

To create metabolic stress we want to use sets that have higher reps, are longer in duration, and take short rest periods so that the body doesn’t have time to fully clear the metabolites before the next set.

Let’s take a 60 second set. You could do 12 reps on a 3011 tempo, or around 24 reps on a 20X0 tempo. The faster tempo will allow you to recruit higher threshold motor units, which will increase the build up of metabolites faster. However, it is also likely that you’ll lose tension at various points of the lift.

The slower tempo won’t recruit such high threshold motor units. However, if you have excellent technique, tension and discipline, you can consciously maintain a high degree of tension in the muscle throughout the full 60 seconds. This has the added benefit of creating occlusion in the muscle. The tension created by the muscle squeezes the blood vessels within that muscle, and partially restricts venous return. This means the blood has a harder time escaping and you get a huge build up of blood and metabolites locally within the muscle. This increased pump effect contributes to cell swelling and the third mechanism of hypertrophy we discussed earlier.
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So Which is Best?

So to maximise muscle development we want to:

1. Optimise tension (sufficient force production)

2. Optimise muscle damage (sufficient total time under tension)

3. Optimise metabolic stress (sufficient high rep, low recovery work)

4. Achieve 1-3 for all muscle fibre types since all of them have the capacity to hypertrophy

The priority is learning tension. You must learn to 1. Create tension in the target muscle, and 2. Maintain tension in that muscle throughout the full range of joint angles.

Therefore beginners (less than 2 years consistent training) should lift slowly enough to learn tension, technique and control. This is the number one priority and many more advanced lifters would do well to remember it.

Once tension, technique and control has been learned then fast lifting is an excellent tool. It will enable you to recruit higher threshold motor units and stimulate new adaptation.

However, slow and controlled movements also have an important contribution. Slow movements will enable you to:

1. Emphasise tension at particular joint angles that may be a specific weakness for you.

2. Emphasise tension at joint angles that typically lose tension when lifting quickly

3. Increase time under tension for more muscle damage – particularly during the eccentric phase

4. Increase the effect of occlusion for the purpose of increasing metabolites.

So once again, as is often the case in the fitness industry, the answer is never clear cut, and the truth is that you need both for maximal muscular development.

Once a client has learned good tension, technique and control, I like to teach them how to lift more quickly because it will enable us to use greater loads and recruit higher threshold motor units. This is particularly useful when we are prioritising heavier lifts and strength training.

When we are prioritising metabolic stress in a workout – for the purpose of muscular development, I will get the client to lift slowly enough that they can maintain tension throughout the full range of the rep and throughout the full duration of the set. An advanced lifter will have the skill to maintain this tension at a higher speed than a novice.

If you do decide to follow a programme based predominantly around fast lifting, then one important consideration is that you incorporate ways to strengthen the parts of the lifts where the tension drops off due to momentum. This is of particular importance for pulling movements. Let’s take the shoulder joint as a prime example. In order to have good muscular balance and safe, stable shoulders in the bottom position of the bench press, you need the antagonists to be strong at the same joint angle. i.e. you need to be strong during a horizontal row when the bar is against your chest. However, if you only do all your pulling movements quickly, you’ll barely have any tension in this portion of the row. I like to add pauses in the shortened position during my pulling movements to ensure I strengthen the weak points.

If you are incorporating both fast and slow lifting into the same workout, it makes sense from a neurological perspective to programme the fast lifts at the start. Otherwise your nervous system would be too fatigued to be able to recruit the high threshold motor units effectively if you programmed them at the end
 
Once tension, technique and control has been learned then fast lifting is an excellent tool
 
Take Aways

For muscular development, the first priority is to learn technique, control and how to create tension in the correct muscle groups throughout the full range of the lift.

Once this has been established, lifting faster will enable you to recruit higher threshold motor units and stimulate previously untapped muscular growth.

Slower movements still have an important place in the programme since they enable you to emphasise tension at particular joint angles, increase time under tension, and increase the effect of occlusion.

So for maximal muscular development it makes sense to include both fast and slow contractions in your programme. You just have to be smart in how and when you programme it.

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