I differ: It is not necessary to "damage you muscles" to make them stronger. While this statement is the opinion held by many conditioning experts, it hints of a lack of understanding of basic muscle physiology. To set out to damage muscle tissue with a workout will ultimately limit performance, enjoyment of exercise and will compromise a person's lifetime ability to participate in healthy physical activity.
Damage your muscles = Damage your health
Here is what I have written previously that is relevant:
If you do a lot of distance running you may be aware that there is a progressive loss of flexibility of the running muscles. This is a progressive process that slowly reduces the long flowing stride of adolescent years to a painful looking middle-aged hobble that looks more akin to a tip-toe through the tulips than an awesome display of sustained athletic prowess. No matter how diligent one is with stretching, the battle to maintain flexibility seems to be a lost cause.
Although cycling is a highly repetitive and restrictive action, there is little consequent loss of flexibility (Mind you, some of the worst sporting posture one will ever see are found in cycling; but this is mostly due to muscle imbalances and sloppy habits).
The differences are due to the differing effects of concentric versus concentric exercise on the body.
All exercise is a combination of concentric and eccentric exercise. What varies is the content.
Concentric = shortening muscle by its own contraction
- Muscle relaxes while lengthening
- No tearing of muscle tissue – no muscle soreness
- Blood flow through the muscle is enhanced
- Risk of muscle and tendon injury is very low
- Recovery is 24-36 hours
Eccentric = contracted muscle is forcefully lengthened
- Blood flow is occluded
- Contracting muscle is forcefully lengthened
- Causes delayed onset muscle soreness
- Risk of muscle and tendon injury is high
- Recovery is 3-5 days
When the tissue that was damaged from eccentric exercise is repairing, fresh collagen is being laid down. The tendency is for this to cause the muscle to lose elasticity and length.
Cycling is close to 100% concentric exercise, as are sports like rowing and swimming. Running, on the other hand, is probably 50% eccentric and this rises to almost 100% when running downhill. Walking is much less eccentric in nature than running, so it is much safer to do.
Eccentric versus concentric explains why a cyclist can ride hard day after day without apparent ill effects and why swimmers can train for hours every day of the week. Because running is highly eccentric in nature the damage to tendons and muscles is high necessitating great care with ensuring adequate recovery between training sessions. This is why a good running programme seldom has you running hard or long on consecutive days.
If a person is doing a lot of eccentric exercise, like running, then there will be a steady loss of flexibility and the development of hard, painful knots within the muscles. This is less of an issue in sports like cycling.
The solution to this is regular deep tissue massages of the affected muscles, daily stretching and keeping fitness at a consistently high level, rather than being a "stop-start" exerciser.
It is not necessary to make muscles sore in order to make them stronger.