Muscle strengthening stimulation
Muscle strength is mainly related to muscle fibres type IIa and IIb, while muscle mass is related to muscle fibres type IIb. These fibres are able to increase their contractile strength and mass with training. Slow fibres have only a very limited ability to do this. A person with marathon-running muscles can never become a "muscle colossus", no matter how much they want to, because slow fibres "don't add mass".
Increasing muscle strength and mass requires training that takes the Heinemann principle into account. According to this principle, during muscle contraction, smaller muscles and slow fibres contract initially. As the load is increased, first the transitional IIa fibres "join" and then, at the very end, the IIb fibres. Let's assume you can lift 100kg at maximum effort. If you lift less than 50kg, only your slow muscle fibres are working. Between 50-75kg, your slow and IIa fibres are also working. IIb fibres only kick in if you are over 75% of the weight.
Summary
- If you are training with less than 50% of the maximum weight, you are doing endurance work. By doing so, you will only increase muscle strength and muscle mass to a limited extent.
- Between 50%-75%, muscle strength and muscle mass will increase
- Above 75%, muscle strength and muscle mass will increase the most. IIb fibers give the greatest muscle mass.
You can "get around" this principle with a muscle stimulator. By applying the right stimulation frequency, you can create a powerful contraction in the IIb fibres even when you are at rest and not trying to lift huge weights. In other words, you can maximise your gains in strength and mass.
Obviously, stimulation treatments are not a substitute for weight training, but an effective complement to it. They are particularly useful if, for example, you cannot develop a particular muscle group or muscle group properly. With stimulation you can precisely "target" even a single muscle!