First, from The Power of Full Engagement:
The concept of maximizing performance by alternating periods of activity with periods of rest was first advanced by Flavius Philostratus (A.D. 170-245), who wrote training manuals for Greek athletes. Russian sports scientists resurrected the concept in the 1960s and began applying it with stunning success to their Olympic athletes. Today, "work-rest" ratios lie at the heart of periodization, a training method used by elite athletes throughout the world.
The science of periodization has become more precise and more sophisticated over the years, but the basic concept hasn't changed since it was first advanced nearly two thousand years ago. Following a period of activity, the body must replenish fundamental biochemical sources of energy. This is called "compensation" and when it occurs, energy expended is recovered. Increase the intensity of the training or the performance demand, and it is necessary to commensurately increase the amount of energy renewal. Fail to do so and the athlete will experience a measurable deterioration in performance.
Energy is simply the capacity to do work. Our most fundamental need as human beings is to spend and recover energy.
We need energy to perform, and recovery is more than the absence of work. It serves not just health and happiness, but also performance. Nearly every elite athlete we have worked with over the years has come to us with performance problems that could be traced to an imbalance between the expenditure and the recovery of energy. They were either overtraining or undertraining in one or more dimensions—physically, emotionally, mentally or spiritually. Both overtraining and undertraining have performance consequences that include persistent injuries and sickness, anxiety, negativity and anger, difficulty concentrating, and loss of passion. We achieved our breakthroughs with athletes by helping them to more skillfully manage energy—pushing themselves to systematically increase capacity in whatever dimension it was insufficient, but also to build in regular recovery as part of their training regimens.
Balancing stress and recovery is critical not just in competitive sports, but also in managing energy in all facets of our lives. When we expend energy, we draw down our reservoir. When we recover energy, we fill it back up. Too much energy expenditure without sufficient recovery eventually leads to burnout and breakdown. (Overuse it and lose it.) Too much recovery without sufficient stress leads to atrophy and weakness. (Use it or lose it.) Just think about an arm placed in a cast for an extended period of time in order to protect it from the "stress" to which it is ordinarily subjected. In a very short time, the muscles of the arm begin to atrophy from disuse. The benefits of a sustained fitness program decrease significantly after just one week of inactivity—and disappear altogether in as few as four weeks.
The same process occurs emotionally, mentally and spiritually. Emotional depth and resilience depend on active engagement with others and with our own feelings. Mental acuity diminishes in the absence of ongoing intellectual challenge. Spiritual energy capacity depends on regularly revisiting our deepest values and holding ourselves accountable in our behavior. Full engagement requires cultivating a dynamic balance between the expenditure of energy (stress) and the renewal of energy (recovery) in all dimensions.
And then from The Art of Learning:
In your performance training, the first step to mastering the zone is to practice the ebb and flow of stress and recovery. This should involve interval training as I have described above, at whatever level of difficulty is appropriate for the age and physical conditioning of the individual. This training could, of course, take many forms: I have already mentioned biking and resistance work, but let’s say you enjoy swimming laps in a pool. Instead of just swimming until you are exhausted and then quitting, push yourself to your healthy limit, then recover for a minute or two, and then push yourself again. Create a rhythm of intervals like the one I described with my biking. With practice, increase the intensity and duration of your sprint time, and gradually condense rest periods—you are on your way! This same pattern can be used with jogging, weight lifting, martial arts training, or playing any sport that involves cardiovascular work.
If you are interested in really improving as a performer, I would suggest incorporating the rhythm of stress and recovery into all aspects of your life. Truth be told, this is what my entire approach to learning is based on—breaking down the artificial barriers between our diverse life experiences so all moments become enriched by a sense of interconnectedness. So, if you are reading a book and lose focus, put the book down, take some deep breaths, and pick it up again with a fresh eye. If you are at work and find yourself running out of mental stamina, take a break, wash your face, and come back renewed. It would be an excellent idea to spend a few minutes a day doing some simple meditation practice in which your mind gathers and releases with the ebb and flow of your breath. This will help connect your physical interval training to the mental arenas. If you enjoy the experience, gradually build up your mental stamina and spend more time at it. When practiced properly, Tai Chi Chuan, Yoga, or many forms of sitting meditation can be excellent vehicles for this work.
As we get better and better at releasing tension and coming back with a full tank of gas in our everyday activities, both physical and mental, we will gain confidence in our abilities to move back and forth between concentration, adrenaline flow, physical exertion (any kind of stress), and relaxation. I can’t tell you how liberating it is to know that relaxation is just a blink away from full awareness. Besides adding to your psychological and physical resilience, this opens up some wonderful and surprising new possibilities. For one thing, now that your conscious mind is free to take little breaks, you’ll be delighted by the surges of creativity that will emerge out of your unconscious. You’ll become more attuned to your intuition and will slowly become more and more true to yourself stylistically. The unconscious mind is a powerful tool, and learning how to relax under pressure is a key first step to tapping into its potential.
Interval work is a critical building block to becoming a consistent long-term performer. If you spend a few months practicing stress and recovery in your everyday life, you’ll lay the physiological foundation for becoming a resilient, dependable pressure player. The next step is to create your trigger for the zone.
And for a small example of how to incorporate this on the physical fitness side of things, here is Art De Vany via his book, The New Evolution Diet:
We are made more for walking and sprinting than for jogging. The fact is, few hunters ever literally ran down prey over the marathon distance of 26.2 miles. American Indians could bring down a horse in a matter of a few days, but that was done primarily by spooking the animal and then trailing it at a distance. Our ancestors sometimes needed to sprint at the decisive moment, when closing in for the kill, although human ingenuity commonly worked better, as when hunters would drive their prey into traps or dead ends from which they could not escape. They definitely needed to sprint when they themselves were the prey. Beyond that, however, hunters lived by the sensible maxim that led our ancestors to exert no more effort than was absolutely necessary.
As in all exercise, intermittency and variety are the goals in aerobic workouts. You want to stop and start, go in an instant from walking to running at top speed for 40 or 50 yards, then amble along until the urge to sprint overtakes you again. When you do this, you exercise all the different types of muscle fiber, whereas joggers work mainly the slow-and intermediate-twitch kinds. Jogging also wastes time because you need to do it for long periods to see any benefit. Mixing up sprints with walks is safer for your heart, too. And there's less stress on your knees, ankles, hips, feet, and back.
You get a good cardio workout just by lifting weights, as I suggest, without a break between sets or stations. When you do it vigorously and with a sense of purpose, your heart will be pumping and your lungs will be working. If you still feel the need for more aerobic exercise, find a game or sport to play. Tennis, racquetball, and basketball are intense, stop-and-start activities, meaning they burn all three kinds of muscle fiber. And they have the added advantage of being fun.
The first thing I do at the gym is head for a stationary bike. You need to warm up your heart, as well as your core temperature, before the real work begins. When you increase your core temperature, the pituitary gland responds by releasing growth hormone. That event is vital to a successful workout: The hormone mobilizes fat to burn for the rest of your session, and even beyond.
Unlike most people at the gym, however, I don't stay on the bike for long—just 6 minutes total, which is enough time to break a sweat and get a good burn going, if you ride as I do. First, I pedal with low resistance at a fast sprint. After 1 minute of that, I turn the resistance up to the maximum possible and ride just as hard as I can for the next 60 seconds. I repeat that pattern twice more—a minute of sprinting at low resistance, followed by one that feels as though I am riding through peanut butter. During that sixth minute, I do my best to max out the meter that measures watts of energy expended. Then I'm done.
Professor Leila Barraj's research actually shows that doing just 7 minutes a week on a stationary bike, riding intensely as I do, can make significant improvements in your ability to metabolize glucose. Other studies show that intermittent, intense sprinting can double endurance capacity in 2 weeks. It's the intensity that counts, not the duration. Other research shows that intensity is the key to having a body that is lean.
There is a power law of exercise, too: Your least frequent, most extreme exertions will have the greatest influence on your fitness. The peak moments of a workout count far more than the amount of time you spend working out. This is why a series of 40-yard sprints at full speed benefits you more than half an hour of jogging. It's also the reason why lifting a weight heavy enough to make your heart pound and your muscles burn counts more than spending hours at the gym always in your comfort zone, never truly challenging your body. When a work-out becomes an unvarying, monotonous routine, it loses its effectiveness.