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More muscle strength than more muscle mass
It was already known that more muscle mass does not always equate to more muscle strength. Various studies on the effects of strength training, for example, have shown that muscle strength typically increases before muscle mass. This increased muscle strength cannot then be explained by more muscle mass. In other studies, it has been found that training with high resistance or heavy weights can lead to the same gain in muscle mass as training with lighter weights, but still results in more muscle strength. I’ve compared this to an American muscle car and a European sports car. The American relies mainly on a very large engine (more muscle mass), while European cars are generally more effective in transferring power to the wheels. Better control of the available power. The researchers at Nebraska-Lincoln wanted to learn more about this difference in muscle control from the nervous system [1]. The researchers did this by measuring how the brain and motor nerve cells, the cells that send electrical signals to the muscles, respond to training with high and lower resistance. Their research shows that training with higher resistance improves the degree to which the nervous system sends electrical signals to the muscles to a greater extent. This enables the muscles to generate more power. Muscles contract when they receive electrical signals originating in the motor cortex (or ‘movement cortex’) of the brain. These signals descend from the cortex down the spinal cord through the spine and activate other motor nerve cells which then activate the muscle fibers. TIP: With the right training and sufficient protein intake, you build more muscle mass and muscle strength. Various scientific studies have shown that creatine, as a supplement to protein, can further increase muscle strength. Their research shows that the nervous system activates more of these motor nerve cells or activates them more frequently with higher resistance. This would explain the higher gain in muscle strength with higher resistance despite leading to the same level of muscle mass. To gain these insights, the researchers had 26 men perform leg extensions three times a week for six weeks. The exercise was performed with a resistance of 80% 1RM (so 80% of the maximum weight they could do for one repetition) or 30% 1RM. In both cases, they trained to failure, as many repetitions as possible. The results in terms of strength and muscle mass were consistent with previous, similar, studies. Both groups gained approximately the same amount of muscle mass, but the 80 1RM group had a greater increase in strength (about 5 kilograms). They also looked at how much the muscles’ maximum capacity was utilized by passing current through the nerves themselves to contract the quadriceps. This allowed them to determine the maximum capacity of the muscles. This was then compared to the maximum effort exerted when the men themselves contracted the muscles. It was already known that you can never utilize 100% of the muscles’ capacity yourself. At the start of the study, the men could use about 90% of the maximum capacity. In the group that trained with higher resistance, this percentage increased by 2.35% (from 90.94 to 93.29 percent). In the group that trained with lower resistance, this was an increase of only 0.15% (90.07 to 90.22 percent). They also looked at this in another way. After three and six weeks, they had the participants perform the exercise step by step starting with 10% of their original 1RM. Then they increased the resistance in steps of 10% up to 100% (the last set consisted of one repetition). They looked at what percentage of the muscles’ maximum capacity was used at each weight. If you exert relatively less effort for the same weight than before, it means that your maximum capacity has increased. In the group that trained with lower resistance, the relative effort was reduced from an average of 56 to 54.71 percent (average of all sets ranging from 10% to 100% 1RM). In the group that trained with higher resistance, however, this decrease was greater, from 57 to 49.43 percent. In other words, whereas they initially had to use an average of 57% of their maximum strength to perform the exercise, after 6 weeks only 49% of the maximum effort was needed.Conclusion: increase in muscle strength
As mentioned, it was already known that training with heavier weights leads to a greater increase in strength despite similar or even smaller increases in muscle mass. This research provides insight into the cause of this. This does not mean that heavier training is always better. Sometimes muscle mass is a greater goal than muscle strength. Also, not everyone is able to train with high resistance. Think, for example, of untrained people, the elderly, and people with limitations. It is also important to consider that the leg extension is a relatively controlled exercise. Especially when there are researchers next to you who check your execution. In practice, many people may sacrifice correct execution of the exercise for a higher weight, which is of course not recommended.References
- Nathaniel D. M. Jenkins, Amelia A. Miramonti, Ethan C. Hill, Cory M. Smith, Kristen C. Cochrane-Snyman, Terry J. Housh, Joel T. Cramer. Greater Neural Adaptations following High- vs. Low-Load Resistance Training. Frontiers in Physiology, 2017; 8 DOI: 10.3389/fphys.2017.00331
