Why building muscle is easier the second time around
When you first begin training, it may seem like it takes longer than you would like to notice gains in strength. Fortunately, there is a scientifically verified phenomenon that allows our muscles to be retrained at a faster rate than they were trained at initially. This means that once you get over the hurdle of training for the first time, you will be able to increase strength more quickly with subsequent training. This is great news for anyone who's taken a couple weeks off from time to time! While increase in muscle size may not be affected differently, regaining your strength actually is easier the second time around.
Here's What Happens
When you train your muscles, new myonuclei are formed within the muscle fiber. Each fiber can develop multiple nuclei. When you stop training for an extended period of time (a few days or weeks), protein degradation exceeds protein synthesis, and muscle atrophy occurs. This atrophy causes your muscles to decrease in size, however no myonuclei are lost. When training begins again, the step of adding new nuclei can be skipped because they are already available in the fiber and are ready to synthesize muscle protein.So, you are able to regain the same level of strength more quickly once those myonuclei exist.
This is advantageous for another important reason aside from just knowing that you can recover from your set-backs more quickly. Scientists have found that the ability to create muscle nuclei is significantly lower in the elderly. Developing more myonuclei through strength training at a younger age can decrease muscle atrophy, helping you maintain strength as you age.
What this means
All is not lost after a minor setback! Once you lay the foundation for strength, your body will more readily regain the strength that you once had. Also, strength training early is imperative to your health throughout your life because developing the nuclei in your muscles that facilitate gains in strength will be more difficult at a later age.