Do you know what happens in the body when you do strength training and how you should train to get stronger?
Strength training strengthens the skeleton, muscles and joints and thereby prevents work and strain injuries and bone fragility. It strengthens the heart and lungs, gives you better digestion, balance, night's sleep, self-confidence and a better relationship with your own body. Also, it increases your metabolism, not only when you exercise.
Research shows that people in the risk zone for lifestyle diseases can reduce their risk by 25 percent after just 20 strength training sessions. It contributes to weight loss, prevents falls and brittle bones. In addition, strength training can prevent cardiovascular diseases, strokes, COPD, mental disorders and drug addiction.
What happens in the body when you do strength training?
- Every time a muscle works to overcome a heavy external resistance, a strong contraction is created in the muscles. The central nervous system communicates with the active muscle by sending electrical impulses that cause the contraction, explains Professor of Sports Physiology at the Norwegian College of Sports, Truls Raastad. He further says that the frequency of the electrical signals sent determines the strength of the muscle contraction. The heavier you lift, the more frequently the signals must be sent - and all the muscle fibers in the active muscle must be involved.
- The muscle contraction itself is created by the electrical signals from the nervous system increasing the calcium content in the muscle fibres. This causes the proteins that create the shortening in the muscle fibres, actin and myosin, to grab each other and pull the muscle together, says the professor.
- There is a direct relationship between how often the electrical signals reach the muscle fibres, how much the calcium concentration increases and how strong the muscle contraction becomes, he adds. In order for the muscle to relax again between each repetition, calcium must be pumped back to the store it came from.
- The force from the muscle contraction is transferred via the tendons to the bones and creates a rotation over the joint the muscle crosses. This is the basis for the movement we see when, for example, we straighten the knee joint and hip joint again on the way up from a deep squat.
Why are you getting stronger?
When you do strength training, you expose the muscle to a greater load than it is used to. This forces the muscles to produce more force-producing proteins to cope with the load - which in turn leads to increased strength in the muscle
A professor of sports physiology at the NIH believes that heavy lifting and few repetitions are the most effective for increasing strength.
- The mechanical pull that is created in the muscle fibers and in the connective tissue between the muscle fibers when we lift heavy sets off a series of signals. These signals increase the speed of muscle protein synthesis, says Raastad.
- We can therefore measure that muscle protein synthesis goes faster in the hours and days after a strength training session. If we repeat this stimulation regularly, at least two to three times per week, the muscle fibers will gradually grow and become stronger with each training session we carry out on the same muscle, he continues. The professor also says that we can become stronger in a training exercise by getting better technique. That we lift in a more appropriate and efficient way, and make better use of the muscle mass we have.
- The more difficult an exercise is to perform technically, the more the strength can be increased by improving the technique, he says.
Heavy weights, few repetitions
According to Raastad, there are several ways to train that can be effective, but he believes that one of the most effective is to train with heavy weights and do few repetitions.
- This is because a large pull in the muscles gives a signal to the muscle fibers that they will grow, he explains. Raastad says you get the best effect if you vary the training resistance within an area, so that in some series you lift so heavy that you only manage around four repetitions, while in other series you lift lighter so that you manage 10- 12 repetitions - given that you want an increase in muscle mass, in addition to strength.
- To the extent that you are interested in increasing strength in a specific exercise, it is important to have some very heavy lifts because it is important to be able to lift the heaviest weights with optimal technique, says the sports physiologist.
Gradual progression
Sports physiology comes at the very end, with some advice to avoid injuries and wear and tear during strength training. - You have to make sure that you have a sensible progression in everything you do. When you start with strength training, you should always run the first training sessions carefully. Then, with relatively light weights, you can learn the correct technique and carefully accustom your muscles to withstand heavier weights and series to exhaustion.
- Furthermore, variation in training resistance and training effort is important. The musculature normally adapts to the training faster than the tendons and tendon attachments, so it may be wise to hold back a little if you start to feel some pain. Then reduce the training resistance for a period until the pain has disappeared, before gradually increasing the training resistance again, he concludes.
The most important exercise
One of the most important things you can train is your legs. The legs get the biggest load throughout the day, and need a dose of leg press or squats a week to keep walking for a long life. Professors Hoff and Helgerud at NTNU, who I mentioned early in the article, have researched training for many years and believe that together with interval training uphill you should train leg presses twice a week, in order to live a long and healthy life.
Effective leg presses: - Four times four repetitions with heavy load. It should be so heavy that you cannot do more than four repetitions.- Relax down to 90 degrees in the knee joint, stop briefly and try to move the weights up quickly.- Add 5 kg each time you manage to complete four times four repetitions.
- Strength can be trained together with endurance. Endurance first provides a good warm-up. - Also train your back and stomach if you train leg presses. This is to avoid damage and wear.