In his book Spirit of the Empty Hand Stan Schmidt mentioned a lesson during which his Sensei asked what his hand would be if it stayed a fist all the time.
I am certain that philosophers and martial artists alike will find a message in that.
As a person practicing a martial art that employs strikes and that uses sparring as a training method- I have a very tangible example of what this metaphor can tell us.
Practitioners of WSKF, Goju Ryu and Jeet Kune Do might know what I am talking about here. Most schools of Taijiquan and JKA Shotokan might not get it, though.
Wenhsiuquan recognises the importance of relaxing muscles in order to gather energy for a strike, but a fair amount of tension is necessary in areas like the legs and abomen to protect the internal organs and to speed up movement.
When facing a sparring partner head-on, a moderate amount of tension in the pectoral muscles protect the ribs as well.
This tension cannot be excessive lest it slows down your movement and robs your strikes of explosive power.
The problem is, though- that maintaining this kind of tension for too long pulls the shoulders forward and bends the spine at the top. We can therefore not walk like this all the time.
I know that most styles of karate do not practice Qigong as part of their warm-up routines and most classes I know off don't even bother to have a warming down routine after class either, much less qigong exercises afterward.
As a result we find a large number of serious fighters with what I have heard some Chinese refer to as "turtle back".
Where most styles of martial art I know want your body to compress itself to become stronger and more efficient at moving- one of the two Wu Styles of Taijiquan (let's not even delve too deep in there. Taiji history is just a mess...) actually recognises the importance of stretching and expanding the body.
I have found some use for this approach in combat, but much more use for the purpose of after training recovery and healing.
One qigong exercise that reverses the effects of tension maintained during karate training (if you are practicing a style that uses this kind of technique) is the one known in Shaolin circles as "Lifting the Sky". I have learnt one version of this exercise from Ashida Kim (Owen! I can sense you snickering!) and another from Sifu Wong Kiew Kit.
What the two versions have in common is that it stretches the body upward. Especially the spine. It forces you to leave that compact state in which we feel safe. The reward, however is that one ends up feeling refreshed and relaxed after class.
I am not surprised to note that some MMA gyms have their fighters attend yoga classes as well. I am certain that fighters that do yoga will tell you something similar to what I have just said.
In a similar manner meditation does for your mind what the Lifing the Sky Exercise does for your body.
Office jockeys who have no interest in learning how to fight will find that this exercise even counteracts the 15h00pm slump.
If your style does not teach you Qigong, Yoga or Meditation I strongly recommend that you start learning it. 2 excellent books that I can recommend to get you started are Ninja Mind Control (Ashida Kim- Yes, I know he has a bad rep, but his teachings actually work.) and The Art of Shaolin Kung Fu by Wong Kiew Kit.
You may also ask Abisha Soans at Martial Arts Forums. She is hopefully still practicing her qigong. :)