When we lift weights the response from the body is determined by the way in which the lift is performed. This is extremely important to understand because there a variety of different adaptations to resistance training.

Let's look at the basics of muscle adaptation, I think you will be surprised at what we find.

When we move resistance (again, bodyweight, free weights, machines, suspension training, bands - anything that overloads the muscle) the body activates muscle tissue to produce force. As we apply more and more force we reach what we call overload. Overload is massively important too cause change in muscle tissue.

Now for the purposes of this discussion lets go large to small, and lets look at a leg extension exercise (seated with knees bent, resistance across low shin, effort is to pull the legs into a straight line). When you perform the exercise your brain activates the quadriceps muscles around the knee, lets focus on the rectus femoris which is central and runs across the kneecap itself. The rectus femoris muscle is made up of lots of motor units, these are bundles of individual muscle fibres.

Now depending on the development in the leg, the body will activate a certain number of motor units. In an untrained leg recruitment will be low, in a more experienced individual recruitment will be higher. As we train the leg recruitment increases as we try to make the job easier. This is how we get stronger.

Take this immediately back to strength and weight loss. We go back to cardio or sport and we have a leg that is better recruited. Moving around feels easier, we are stronger and we are more efficient. But more, not less energy is being burned in the movement, we are just better at doing it. If more energy is being burned, more cells are being emptied, we have better cellular permeability and our much needed flow of nutrients is moving. We benefit from being stronger.

So we increase recruitment. Do we get bigger? At first, in an untrained leg it is likely that we some increase in leg circumference due to the increase in motor unit recruitment, more blood flow, glucose delivery to the muscle and glycogen storage. But again this is a temporary effect and can be reduced by emptying these stores. The muscle has not actually grown, in terms of long term adaptation.

The long standing effect is determined by how we actually perform the repetitions, how much overload we get and, more precisely, the tension we create in the muscle fibres.

Let's look at the basic adaptations in their simplest forms.
Myofibrilar hypertrophy is when we increase recruitment of motor units, or groups of muscle fibres. We switch on more muscle tissue due to an increase in work required. This is massively important to understand for athletes and female lifters who do not want to build massive amounts of muscle tissue.

We are looking for minimum tension in the muscle as we perform these repetitions. Repetitions will be quick and relaxed. We prescribe tempo by a count in seconds for a lift, so for example our leg extension might be:


This would be a fast extension of the leg (X), a one second pause at the top to stabilise the joint (1), a fast lowering (X) and a 1 second pause at the bottom.

This is a good way to learn good form. The pause is there to prevent swinging or bouncing of the weight and the fast raising and lowering of the weight stops the muscle becoming filled with blood.

What does this mean? Well when we perform the exercise the body increases blood flow to the area in order to get the work done. But if we retain too much tension in the muscle fibres we are going to get stretching and micro tearing in the fibres (hypertrophy). This is going to lead to soreness after the workout and an increase in muscle fibre size, if supported correctly by diet.

Now you may be thinking "I don't want to increase muscle size!", but by understanding the mechanism by which it takes place it makes it easier to avoid, which is massively important for many athletes and female lifters. We need to keep tension low, this could be heavier weights performed very quickly for a few reps or a lighter weights performed for more reps, again at low tension.

If you do want to grow muscle, you need to practice maintaining that tension in the muscle. For an athlete or sportsperson looking for myofibrilar hypertrophy (an increase in recruitment) without hampering their athletic speed, we might look at slowing the lowering of the weight whilst keeping a quick contraction. Our tempo becomes


So we raise the weight quickly (X), hold for a second (1), lower slowly under control (3), and pause for a second at the bottom (1).

The eccentric portion or lowering of the weight is when we get the most neural feedback to the brain and the most activation of motor units.

This protocol would also be a good protocol for someone who has spent some time with the first tempo and is looking to further improve. You are going to see improvements in strength and a mild increase in muscle size. You are also going to see mild soreness with this programme.

Finally, our body builders. Now these are the guys and girls who want tension in muscle. They want blood to flow into muscle, keep it there and cause the stretching and damage to muscle fibres to allow an increase in muscle fibres cross section. The sarcoplasm of the muscle cell fills with fluid and glycogen and we create that deliberate size in the muscle. They do this by not releasing the tension from the muscle. This is hard, hard work and may require you to use a lighter weight to start with. It is hard work for the heart and lungs (to pump the blood around) as well as the muscle so you will be puffing. 

Lets look at an example tempo, still on our leg extension.


Now we are controlling the weight, squeezing the muscle hard constantly throughout the exercise. We have a 2 second raise (2), a 2 second pause (2), a 4 second lowering (4) and a 2 second hold at the bottom (2). The muscle is constantly under tension for the whole set. Blood flows into the muscle and at no point do we release that tension. This is going to cause the muscle fibre to swell, stretch to the point where we get micro fibre tears in the fabric of the muscle and we can then repair these and build up on this increase in size another day.

Now, reading that last paragraph, it suddenly becomes unlikely that many of us have caused true hypertrophy in the muscle. Most of the increase in size we see will be a temporary increase in blood flow, glucose delivery and glycogen storage.

Men who have walked out the gym feeling like Arnie and then saw their size disappear hours later will know exactly what I mean.

Bodybuilders, take note. It is going to take a lot of effort to create that tension in the muscle. Many gym rat bodybuilders fail for a very surprising reason, namely trying to lift too heavy. Heavy weights become neural (strength training) and they struggle to create and maintain enough quality tension in the muscle. Lower the weight a bit, create a squeeze in the targeted tissue and see how you go.

Bodybuilders still need the first two tempos to get stronger but tempo 3 is where they will see their development.

Our weight loss members, ladies and athletes - keep the lifts quick and tension low, improve neural strength and myofibrilar recruitment. Switch on more muscle fibres, improve your tone, physique and increase your nutrient turnover. You will not grow massive amounts of muscle just by stepping in the gym and by lifting weights. As you read above it takes a lot of deliberate, hard work. Get strong, get lifting.

Bodybuilders - get that tension in the muscle. Become a master at contracting muscle tissue, creating blood flow and causing growth. Know where you want the growth and make sure that area is strong enough and innovated.

I hope that is a help and allows you to understand the differences between different types of lifting.

Know your goal, apply the appropriate amount of tension.

Happy lifting.

Best regards

Chris Adams