When we engage in fitness training, our physical fitness initially declines, and then gradually recovers through proper nutrition and sleep, sometimes even surpassing the original level and becoming “stronger.” This is the principle behind how fitness improves our physical fitness.
If we don’t allow our bodies enough time to recover and subject ourselves to another round of training, our fitness levels will only further decline. This condition is known as “insufficient recovery,” and if it persists for a long time, it can lead to overtraining.
Therefore, it is not only important to be consistent in our fitness routines but also to learn how to rest properly. “Adaptation” takes time.
When we consistently and regularly challenge our bodies with exercise and provide sufficient recovery, our physical capabilities gradually improve.
I. After fitness training, the body feels weak for a period of time.
To begin with, let me share a somewhat alarming fact: fitness alone does not make the body stronger. It is the combination of fitness, nutrition, and rest that leads to increased strength.
After fitness training, the body is actually in a state of extreme weakness.
When we train, our physical fitness initially declines, and then gradually recovers through proper nutrition and sleep, sometimes even surpassing the original level and becoming “stronger.” Therefore, after fitness training, depending on the level of rest, two situations may arise:
- After training, with sufficient rest, the more we train, the better our physical fitness becomes.
- After training, without adequate rest, the more we train, the worse our physical fitness becomes.
This is why post-training nutrition and sleep are crucial. It’s the reason why many fitness enthusiasts say, “Training is only 30%, eating is 70%.”
Now, I want to explain the principle of how to truly improve your physical fitness and why some people experience sudden death after fitness training.
The majority of fitness books and articles fail to clearly identify the most important theory behind improving physical fitness. This theory is well understood by experienced fitness enthusiasts but is often not elaborated on extensively due to its foundational nature.
This theory is called the “principle of adaptation.”
Through the principle of adaptation, we can quickly understand the key to designing training programs and the value of relaxation and recovery.
II. The basic principle of “increasing physical fitness”
Experienced fitness enthusiasts will notice that after a period of strength training, their strength increases, muscles grow, and even skinny individuals appear more muscular. Similarly, after a period of running training, they find that they can run more easily, steadily, and even faster within a given time and distance. After playing badminton for a while, they notice improved agility and fluidity in their movements on the court.
In fact, regardless of strength training, displacement training, sports, or other competitive activities, as long as individuals undergo a period of training, they will experience a certain level of improvement in that particular activity.
In sports science, this phenomenon is known as “adaptation.”
“Adaptation” is a training phenomenon and a fundamental principle of sports science. Its theoretical basis comes from the General Adaptation Syndrome (GAS) proposed by the Canadian pathologist Hans Selye, which is sometimes referred to as the “stress” theory.
The general theory of biological adaptation states that when organisms face challenges such as infection, toxicity, trauma, nervous tension, high or low temperatures, muscle fatigue, or radiation, they often respond in a fixed manner to maintain the stability of their internal environment. This is called “adaptation” (or “stress”).
Essentially, “adaptation” is a physiological response aimed at maintaining life and facilitating recovery after damage.
Externally, “adaptation” refers to the process by which our bodies resist and adapt to external environmental pressures. This process can generally be divided into three stages:
- Alarm phase: During this phase, adaptation has not yet been acquired, and our capabilities decline.
- Adaptation phase: During this phase, adaptation reaches its optimal state, and our capabilities gradually increase.
- Exhaustion phase: During this phase, adaptation gradually diminishes, and our capabilities return to normal.
This phenomenon of “adaptation” also applies to sports activities.
According to the theory of adaptation, coaches need to apply an appropriate training stimulus to athletes to keep them in the “adaptation phase” and maintain a continuous improvement in their physical capabilities.
Let’s take strength training in our fitness routines as an example:
Alarm phase (decline in physical capabilities): When we first step into the gym for strength training, our bodies experience a different kind of stress. During the training, our muscles start to swell, and we feel fatigue and a tearing sensation. The nervous system recruits more muscle fibers for force production. The day after training, our muscles ache intensely, making it difficult to lift heavy objects with our arms or climb stairs due to leg soreness. The nervous system’s ability to recruit muscle fibers also decreases. This stage belongs to the “alarm phase” of general adaptation syndrome, where adaptation has not been acquired, and our capabilities decline.
Adaptation phase (strengthening stage): After a few days, when the soreness subsides completely, we return to the gym for strength training. We realize that we can actually lift more weight in bench press/squat/deadlift compared to the previous session, and our bodies don’t ache as much afterward. This stage belongs to the “adaptation phase” of general adaptation syndrome, where adaptation reaches its optimal state, and our physical capabilities gradually increase. This is the stage where we become “stronger.”
Exhaustion phase (return to normal): However, if we stop training for some reason, our muscles will shrink, and the nervous system’s recruitment ability will decline. The previously acquired adaptation gradually diminishes, and our bodies return to their initial state. This is the “exhaustion phase” of general adaptation syndrome.
