Tao of Training
First, rest is training. Our bodies need recuperative periods between training sessions. This functions on both an extremely short and long time scale. Rest periods and intervals are necessary between rounds and within a practice session. No one lifts weights constantly for an hour nor can you spar uninterrupted for the same period. Rest breaks exist, however short or seemingly inadequate. Similarly, taking a rest day is often not only desirable, "resting is training, too." Hardcore martial arts and combat sports training can be an occupation or as demanding as a second job, taking a vacation won't hurt.
Training no matter what kind is phasic. Your life outside the dojo/gym/ring effects the frequency, timing, and intensity of practice. Your coach or instructor's current goals will vary. Your health and injury status will wax and wane. The next event be it a certification test, competition, or seminar will dictate training values both before and after. This will alter practices and the why of training.
However the tao of training is more than that. I train in a Jeet Kune Do and Brazilian Jiu-Jitsu class where the class is roughly split into 45 minutes each of "striking" and "grappling". Many of my classmates divide themselves into these rough categories. They excuse perceived inadequacies in one portion of practice and then highlight their accomplishments in the other. Fundamentally this is like training your strengths and ignoring your weaknesses as well as evaluating yourself against others rather than using your own progress as a barometer. Sure you might be "better" at one but how close to perfect are you with either? That's like saying a million is closer to infinity than hundred. The body mechanics of stickfighting is not dissimilar to boxing or, surprisingly, wrestling. They all have hip motion, level changes, and footwork. So then by isolating our perceived strengths and weaknesses we are in fact slowing our development and understanding of not only combat sports as a whole but the element we might most enjoy.
Training is too often self-serving and egocentric. The best example is when people do focus mitt or pad drills. More people always run and get gloves than pads although they know that both sides will be doing the same number of rounds. Once the majority of eager hitters is trimmed the yin-yang of pad work begins. On one side the pumped, excited hitter and on the other the apathetic, bored holder. The hitter has the easy job: hit the target and defend when told to do so. The holder has the hard job, they are coaching, encouraging, and coming up with sequences as fast as they can. They are intercepting strikes and generating reactions. The holder is training both their offense and defense. They see how combinations work and train their reactions as much as the hitter does if they only try and do so. If you hold apathetically and concentrate solely on your time as the hitter you are only achieving half a training session.
Training is not about physical victory. When I train timing or sparring rounds with fighters, I push the action and try things that I might not normally do. I don't want them to fight me, but I want them to be exposed to a wide array of energies. If they beat me, they beat me. I'll tap in practice or get hit if it helps them win in competition. At this point it's not about me, but about them. However, by freeing myself from the anxiety of losing in the gym I learn and practice new skills.
I still show up to practice when I'm not a 100% or contagious. You can always learn by observing and taking notes. You can always contribute to training even if it is a simple as yelling encouragement, preparing equipment, or timing rounds. If wheelchair-bound Doug Blevins can coach football kicking how can I have an excuse when I'm tired or my knees are sore to not practice my art.
Thus the why of training has to be reviewed. Training is mind-body-spirit, do not solely focus on the body. Every time we practice we hone our brains and temper our souls sometimes with a great physical workout, sometimes not. So what if it was a "bad" practice for you. Did you contribute to others development? Did you learn one little thing? Did you at least get away from the house to clear your head? In other words, to quote sensei Doug Musser blackbelt in Danzan Ryu Ju Jitsu, "its been a good [practice] if you can go home and wipe your own @$$." This after one of his pupils broke both shoulders in practice and was unable to perform even the simplest of hygiene without assistance for six weeks.