Whenever I watch a Bruce Lee film with friends or family, the fight scenes were always what stuck out as revolutionary to them. Surely, they were right, but the part of the films that stuck with me was Lee’s use of dynamic tension. Whether warming up for a death match with Chuck Norris, or simply going through his regular training motions on a sunlit balcony, Bruce Lee’s lat spreads, fist clenches, and other dynamic tension techniques always drew my curiosity and attention.


Charles Atlas coined the term “dynamic tension” and his studies on the topic revolutionized the physical culture era of the early 20th century. He attributed much of his strength and physical development to dynamic tension training.


Watching Bruce Lee movies and reading about Charles Atlas made me think about something my martial arts mentor taught me: slow is smooth, and smooth is fast. Dynamic tension has been shown to improve muscle control and strength, but could it also be a secret key to speed development? 


sprint hurdlesTraining dynamic tension will build speed and athleticism.  [Photo courtesy of Pixabay]


Slow Is Smooth, Smooth Is Fast

For my answers, I looked to a time before either Bruce Lee or Charles Atlas were even a thought: the era of ancient martial arts. The Shaolin monks have a training classic from many years ago called the Yijin Jing (literally the “Muscle/Tendon Change Classic”) that contains eighteen exercises intended to develop speed, strength, mobility, endurance, and balance. The Shaolin monks have certainly developed all these qualities from their training.


Reading about the exercises, I realized that they are fundamentally dynamic tension exercises. One of the instructions for how to perform the exercises is “Movements are slow but full and tensed, face and body shows relaxed attitude.” That’s the core of dynamic tension training - slow, but tensed and deliberate movements. How could this possibly relate to speed training?


The goal of plyometric training is often for SPP (specific physical preparation), meaning that someone will explosively train a specific movement to increase speed through nerve and fast twitch muscle development. The problem is, SPP often fails to account for the health of the tendons. Training that emphasizes such explosive movement usually relies on momentum, and the torque on the connective tissues from momentum training often does more harm than good.


Furthermore, when training such momentum and speed, it can be even more difficult to truly master the technique, because continuous repetition at high speed is mistaken for smoothness.


Dynamic tension training requires slow movement, which is likely why many people believe that it isn’t the key to speed training, but that would come from a misunderstanding of muscle development. Intensity is what determines the development of your muscle, not speed.  


  • Slow twitch fibers are used for endurance, and recover quickly. This would include the muscles in your neck or lower back, for instance.
  • Fast twitch fibers are responsible for quick and powerful muscular contractions, like the muscles in your quadriceps. They produce more force, but are quicker to fatigue than slow twitch fibers.
  • Intermediate fibers possess the qualities of both slow twitch and fast twitch fibers.


If your training is not intense enough to require your fast twitch muscles to fatigue, your slow twitch muscle fibers, which recover quicker, will develop more and take on the work load. If training is slow but has tremendous intensity, it will still develop fast twitch muscle fibers. Slow but intense movement will depend on your own muscle control development. And therein lies the key to the smoothness – muscle control.


What people sometimes attribute to not having enough fast twitch muscle fibers is actually awkward or slower speed and movement. More often than not, the issue is muscle memory. If you constantly perform a movement, your nervous system remembers the movement to make it more efficient and reduce the amount of muscle fibers recruited to perform it.


Walk Your Way Strong

Performing slow dynamic tension exercises can help your nerves and muscles get used to performing the movements you want to train, and builds incredible speed when you perform the same movements without the tension.


When you are exercising to develop speed of technique, or maybe just doing some grease-the-groove training, try adding some dynamic tension to your movements. One way I find I can easily train it is by walking – simply walking while tensing the muscles in my legs has helped their overall strength and speed develop.


My personal favorite walk to couple with dynamic tension is duck walking, which is essentially walking in a low squat position. Tensing the muscles in your legs as you walk makes you very attentive to your movements, as you could easily lose balance if you move too quickly. Slow, deliberate steps while flexing will strengthen your thighs as well as your calves and tibialis (a muscle that more often than not is neglected).


For an advanced variation, stomp instead of walking, and tense your muscles right before your foot stomps the ground. Flexing your legs will help the shock transfer to your muscles and tendons rather than just your joints. This is a training technique that is fundamental to Bajiquan martial arts practice, called zhenjiao (stomping foot). Trained progressively and consistently, your legs will become rock solid, your joints will work like springs, and the power output of your legs will be optimal.


Slow Down to Speed Up

In my last article there is a video of Sensei Shinyu Gushi performing the sanchin kata with hard dynamic tension. He is well into his 70’s in the video, yet his physique and speed, even with the tension, displays a level of physical mastery and muscle control not often seen.


The dynamic tension I’ve performed with my upper body, along with isometric training, has developed the explosive strength I need to perform strength feats like bending horseshoes or railroad spikes. But furthermore, it has allowed me to apply sharper technique to all things I apply it to: basketball, football, martial arts, and bodyweight training, etc.


And above all else, know this: slow is smooth, and smooth is fast.


Become a student of strength:

Lessons In Fitness and Life from Bruce Lee