Principles of flexibility training

Adapt to training goals, respect individual differences, gradually load, and take into account strength controllability. There is no requirement that you "press until it hurts" or "practice until you can do the splits."

Last week I met a young girl who had just graduated from the gym. She followed the "7-day quick hip opening tutorial" online for three days. She was so painful that she had to hold on to the handrail when going down the stairs. When she lifted her trouser legs, she saw a bruise on the inside of her hip. It was a mild strain of her hip adductor muscle. Her original request was just to improve the tightness in her hips caused by sitting for a long time, so that she would not feel sore after sitting for a long time. However, she mistakenly applied the tutorial for flexibility improvement enthusiasts to herself, and she fell into a trap in the typical first step.

Practitioners in different fields have very different requirements for flexibility training, so there is no need to argue about right or wrong. I know a powerlifter who has competed in intercontinental competitions. When sitting, his fingertips can just touch his knees. When he deadlifts 260 kilograms, his movements are not wobbly at all. For him, the hip flexion flexibility is just enough to touch the starting position. If he practices too much, it will cause the joints to unload at the bottom of the starting position, which will result in a loss of results. But if you ask teachers who teach Yin Yoga, you will get a completely different answer: they will recommend that you stay in the stretching position for 3-5 minutes, and even allow assisted compression to deepen the range. After all, their training goal is to release deep fascia and complete advanced postures. The logic is fundamentally different.

Before, the sports medicine community had been arguing for almost ten years about "whether static stretching can be done before training." Research from earlier years concluded that a single set of static stretching for more than 60 seconds will significantly reduce muscle explosiveness and is not recommended before strength training; however, the latest meta-analysis in 2023 has reversed the old conclusion: as long as a single set of stretching does not exceed 30 seconds and the total duration is controlled within 5 minutes, the impact on strength performance is almost negligible, and on the contrary, it can reduce the risk of strain in old injured areas. I have an old rotator cuff injury. Before every chest push, I statically stretch the pectoralis minor for 30 seconds. The feeling of joint compression during push is obviously much lighter. It is unnecessary to adhere to the rule of "only dynamic stretching before training".

After all, what is most easily overlooked is individual differences. Just like some people are born to be able to drink two kilograms of white wine without getting drunk, while others blush after taking a sip of beer. The innate gap in flexibility is much greater than you think. I once coached an amateur runner whose natural hip flexion range of motion is 15 degrees smaller than that of ordinary people. I followed the tutorial for a month and tried to increase the stride length by pressing the hips, but the hip joints still hurt when running. Later, I gave up the obsession with stride length and focused on cadence. The whole marathon time improved by 3 minutes, and there was no more pain. There are also people with naturally loose joints who can bend their arms more than 20 degrees and touch their navel casually with their backhand. Such people must not blindly follow the trend of flexibility training. The stability of the joints is poor, and if they are stretched again, they will easily cause dislocation and chronic wear and tear.

To use an inappropriate analogy, flexibility is like the rubber band you buy. If you usually use it to tie your hair, just pull it to a length that can be wound around three times. If you have to pull it to the limit and break it quickly, it will either directly collapse and strain, or it will lose its elasticity after being pulled loose, and you can't even tie your hair. Many people think that the more flexible you are, the better, but this is not the case - your flexibility must match your muscle strength. If you can do the splits, but your legs shake like a sieve when you do the splits, and you cannot control your core at all, then this kind of flexibility is of no use except to look good in photos, and it will make you prone to injury.

Don’t be too eager for quick success. I previously adjusted my limited ankle dorsiflexion. It took me a full 3 months to adjust the dorsiflexion from 10 degrees to 15 degrees, which was just enough for me to squat to the end without any injury. Every time you stretch, it only needs to be to the point where you can feel an obvious stretch but still be able to speak normally. If the pain is so painful that you can grin and bear it, it’s probably exceeded the safety threshold. Don’t believe the nonsense that “pain means it’s effective.” If you get a strain, it’s you who will be in pain.

In fact, in the end you will find that there is no universal standard? The purpose of practicing flexibility is to make yourself move more comfortably. It is enough for sedentary people to turn their heads without pain, squat down and tie shoelaces without difficulty, golfers to not pull their thighs when changing directions, and runners to land without their hips stuck. If you can't even walk after practicing, that's not training, it's asking for trouble for yourself.