Strength training strengthens bones, muscles and joints and prevents repetitive strain injuries and osteoporosis. It strengthens the heart and lungs, giving you a better digestion, balance, night sleep, self-confidence and a better relationship with your own body. Moreover, it increases your metabolism, not only when exercising. (Norwegian Health Informatics (NHI))
Research shows that people at risk of lifestyle diseases can reduce the risk by 25 percent after just 20 workouts focusing on strength. It contributes to weight loss, prevents falls and osteoporosis. Additionally, strength training can even prevent cardiovascular disease, stroke, mental illness and substance abuse.
“Every time a muscle is working to overcome heavy external resistance a sharp contraction within the muscles is created. The central nervous system then communicates with the active muscle by sending electrical impulses that create contraction,” Professor of Sports Physiology at the Norwegian School of Sport Sciences, Truls Raastad, explains.
He goes on to say that the frequency of the electrical signals transmitted determines the power of the muscle contraction. The heavier you lift, the more frequent the signals are sent, and all the muscle fibres in the active muscle has to be involved.
“The muscle contraction generated by the electrical signals from the nervous system increases the calcium content in the muscle fibres. This causes the proteins that create shortening of muscle fibres, actin and myosin, to take hold of each other and pull the muscle together,” the professor says.
”There is a direct correlation between how frequently the electrical signals reach the muscle fibres, how much the concentration of calcium increases, and how powerful the muscle contractions are,” he continues.
For the muscle to relax in between each repetition, the calcium must be pumped back to where it came from.
“The force of muscle contraction is transmitted through tendons to bones, creating a rotation of the joint which the muscle passes over. This is the basis for the movement we see when we for example straighten the knee and hip joint on the way up from a deep squat.”
When you work on building your strength, you expose muscle to a greater load than it is accustomed to. This forces the muscles to produce more power-producing proteins to cope with the load, which again leads to increased strength.
“The mechanical pull that is created in the muscle fibres and in the connective tissue between the muscle fibres sets a series of signals in motion. These signals increase the rate of muscle protein synthesis,” Raastad says.
“Therefore, we are able to measure that muscle protein synthesis happens faster in the hours and days after a strength workout. If we repeat this stimulation regularly, at least two to three times per week, muscle fibre gradually grows and becomes stronger for every workout we implement on the same muscle,” he continues.
The professor also says that we can increase the strength even more by improving our technique: By lifting in a more expedient and efficient manner and utilise our muscle mass better.
“The more challenging an exercise is to perform in terms of technique, the more your strength increases when you improve the technique,” he says.
According to Raastad, there are several ways to train effectively, but he thinks some of the most effective is to work with heavy weights and few repetitions.
“This is because a big pull in the muscles sends a signal to the muscle fibres that they need to grow,” he explains.
Raastad says you get the best effect if you vary the exercise resistance. In some sets you lift so heavy that you are only able to do around four repetitions, while in others you lift lighter so you are able to manage 10-12 repetitions. Varying like this will give you increased muscle mass as well as increased strength.
“If you are interested in increasing your strength in a specific exercise, it is important to include some very heavy lifts. This is because it is important to lift the heaviest weights while ensuring your technique is optimal,” says the sports physiologist.
Finally, Raastad shares some advice on how to avoid damage and injury during strength training.
“You must ensure that you have reasonable progression in everything you do. When you first start with strength training, you should always be careful for the first sessions. Using relatively light weights, you should learn proper technique, gently enabling the muscles to withstand heavier weights and more repetitions.”
“Moreover, the variation in resistance training and training efforts is important. Muscle normally adapts to training faster than tendons, so it is recommended to be careful if you start feeling pain. Reduce the resistance for a period until the aches have disappeared, then gradually increase again,” he concludes.
One of the most important body parts to work on is your legs. They get the biggest impact throughout the day and need to be strong to keep you upright throughout life. Professors Jan Hoff and Jan Helgerud at NTNU have done a lot of research on training. They have reached the conclusion that the most efficient workout for your legs are leg presses or squats with heavy resistance, along with interval training.