The core is so vital that Bruce Lee trained them every day. His purpose was not to crush but stimulate them to be stronger over time. I don't know of anyone who trained their abs more than Bruce. I also don't know professionals who are as fast and explosive as Bruce. Even Bolo Yeung, who doubted Bruce Lee's strength, said Bruce is not just quick and explosive but strong. So, I believe if Bruce's main focus of power and explosiveness was his abs, then maybe we need to look into it.
You can train your abs every day. They are constantly used when sitting, standing up, walking, running, strength training, or doing martial arts. Their strength is based on tension and stability that initiate explosive movements. You can train strength and slow-twitch muscles one day and fast-twitch muscles and explosiveness another. Training every day is ok. It just depends on the intensity and how you do it. You cannot train explosive every day.
Bruce Lee’s Ab training Pointers
1) Train your movements fast and concentrate, focus, and feel the quality of each rep. Do not just do mindless movement. If you just move mindlessly, then your abs will not develop effectively.
2) When you cannot do any more reps, continue by doing short burst half reps. Bruce believed that these short bursts caused more separation and development when the abs burned.
3) At the end of each abdominal session, do static isometric contractions.
4) Exercise your abs daily and with patience. Results will come.
5) The abdominals and waist region coordinate all body movements and act as the center or generator. Therefore, you can promote the ability to control the body's action and master your will more easily.
6) The proper way of doing a sit-up is not just going up and down, but to curl yourself up, to curl yourself back up, like rolling up a roll of paper.
Watch this video to see how to do Bruce Lee’s abdominal exercises.
Lee believed the food you ate is what produces the thickness and esthetics of your abs. So, he always ate the proper nutrition and had a solid diet free of starches, sugars, fried foods, and alcohol.
Lee used these five basic exercises.
Waist Twist- 4 sets of 70
Sit-Up Twist- 4 sets of 20
Leg Raises- 4 sets of 20
Leaning Twist- 4 sets of 50
Frog Kicks- 4 sets as many as you can
Stomach and Waist Exercises (2 Sets)
- Roman Chair Sit-Up
- Leg Raises
- Side Bends
He also used isometric holds, for example:
Bruce used high reps and till exhaustion like waist twists, static isometric contractions like dragon flags, and short bursts after exhaustion to train his abdominals. Using all three methods developed Bruce's defined explosive core. So, the strength of their stability leads to generate tension rapidly to kick or punch explosively. The abs are constantly working to stabilize your spine, so they need to be fatigue resistant.
The abdominal training pointers and exercises are referenced from the book "Bruce Lee: The Art of Expressing the Human Body by John Little."
If you would like to know more about speed and explosiveness check out my books: