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Four Rules of Intensity for Anaerobic Workouts

by Brad Kearns
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Perhaps the #1 problem hindering fitness progress and optimum health among endurance athletes is too much anaerobic exercise.

If you want to succeed with your efforts to reach and maintain your ideal body composition, you must not conduct anaerobic workouts indiscriminately.

Anaerobic workouts can be a powerful tool for fitness improvement, but they can also be your worst enemy, leading to burnout, sugar cravings and an inability to efficiently burn body fat.

Here are my Four Rules of Intensity - simple guidelines that will help you efficiently manage energy output for continued fitness progress and prevent burnout.

Rule #1: Always develop an aerobic base before engaging in ANY anaerobic exercise. For beginning exercisers this may take up to a year of steady aerobic workouts. Experienced athletes find a two-month period at the beginning of the exercise season is sufficient to develop a base. You can measure your aerobic development with MAF performance tests to ensure your base building is successful.

Rule #2: Only do anaerobic workouts when you feel 100% physically energized and mentally refreshed. Anaerobic workouts are intense, physically stressful efforts. You should never force your body to exercise at high intensity if your spirit is not willing. You will not recover adequately nor will you obtain the desired fitness benefits if you push a tired body through an intense workout.

Diligent exercisers have long been under the mistaken impression that fitness progress is measured by workout difficulty or workout frequency. When you treat your body like a rock ("push it hard enough and it will progress"), you violate the laws of nature and balance.

Your body needs a constant balance of stress and rest. Even though it may be an enjoyable "release" from other forms of stress, anaerobic exercise is merely another form of physical stress. Thus, it must be placed on the same side of the balance scale as all other forms of stress in your life.

This stress needs to be moderated by energizing aerobic workouts and other pursuits that help restore and replenish your physical and mental energy.

Rule #3: Never conduct anaerobic workouts for longer than six consecutive weeks without a break. Even if you only do one anaerobic workout a week, you are engaged in an "anaerobic training phase." After six weeks of anaerobic workouts, you must take a minimum rest period of three weeks. During this time, drastically reduce your workout frequency and never exceed your maximum aerobic heart rate during any workouts.

Over the next three weeks, you can rebuild your fitness base with aerobic base training. For each block of anaerobic training during the year, plan an equal block of time afterwards to refrain from anaerobic workouts.

Every time your body is exposed to anaerobic exercise, it needs an adequate recovery period afterwards to fully absorb and benefit from this intense training. Only then will you experience the desired fitness benefits from intense workouts.

Rule #4: Never exceed 10% of weekly workout time at anaerobic heart rates. During your carefully controlled anaerobic training phases, it is essential to minimize the total time you spend at anaerobic heart rates to ensure that you do not exceed 10% of your total workout time for the week.

For example, if you do three 40-minute runs per week and two other cross-training cardiovascular workouts totaling 90 minutes, this is an accumulated weekly workout time of 210 minutes (3 1/2 hours). Thus, your anaerobic efforts are limited to 21 minutes for the week. This would entail one typical interval workout.

For the 10% rule, you are counting actual exercise time at anaerobic heart rates. While your interval workouts may last 40 minutes, typically only 12-20 minutes are conducted anaerobically, with the rest devoted to warm-up, cooldown and recovery between anaerobic efforts.

Following these 4 Rules of Intensity requires a discipline and focus that may feel frustrating and stifling at first. You will sacrifice some of the spontaneity of your workouts and have to constantly temper your competitive instincts.

Following these guidelines will diminish the measure of short-term gratification that you experience from pushing your body to an exhilarating, maximum effort on a regular basis.

However, the reduction in short-term gratification will be more than compensated for by the tremendous benefits you enjoy through a carefully planned training that emphasizes aerobic exercise: increased energy levels, optimum health and continued improvement in your fitness level.


Brad Kearns is a former national champion and #3 world-ranked professional triathlete and popular author, speaker and coach in the fitness world for the last 16 years. Brad’s Power Month book/CD offers a focused, 30-day program with daily Action Plans to improve dietary habits and food choices, goals and heart-rate based periodization training schedule, general health and stress management and personal growth issues. His www.Bradventures.com offers a healthy, holistic approach to performance nutrition and healthy, balanced lifestyle practices.

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