Jes Reynolds…Your Fitness Coach

In my 10 Fitness Mistakes post, I discuss tracking your progress as an important part of getting fitness results.  A fitness assessment can offer concrete feedback such as body fat percentage, flexibility, muscular strength, and cardiovascular endurance.  Other tests, such as VO2 Max or metabolic testing can be extremely helpful depending on your specific goal but are much less commonly available.

The objective results of these types of measurements far outweigh using the mirror as a source of feedback.  Feedback from the mirror is extremely subjective and people often imagine they are either gaining/losing weight or getting bigger/smaller based on the way they feel.  This has a lot to do with the psychological component of weight loss which can be extremely tricky.

Body composition or body fat testing estimates the percentage of total body weight that comes from fat vs. lean mass.  Knowing your body composition is useful when setting weight loss or physique oriented goals.  The most common form of body fat testing is performed using skin fold calipers.  Girth measurements, BMI, and bioelectric impedance are also commonly used methods for estimating body composition while the least common, hydrostatic weighing and air-displacement (BodPod), are actually considered the criterion measurement technique.

Be aware that each method of body fat testing has a margin of error based on both the limitations of the test and the person performing the test.  For example, skin fold measurements are accurate within +/- 3.5% and that’s just in relationship to the test.  There is an increased margin of error if you use different people to take the measurements and if the tester measures with differing technique at different times.  It’s best to use the results as a reference point to guide you towards your goals instead of focusing solely on the number.

A fitness assessment is a valuable tool, especially for beginners designing a new exercise program. You can use your results to identify your current fitness level, determine a progressive exercise program and track your progress. Assessment tests usually cover a variety of health and fitness categories including:

• Resting heart rate and blood pressure
• Exercise heart rate blood pressure
• Muscular endurance and strength
• Aerobic capability
• Percent body composition
• Flexibility

Once you go through the battery of tests, the results are generally put into a computer database, measured against medical recommendations, and compared to others of the same age and sex.  This allows you to see how you measure against your peers and will hopefully be a source of positive motivation and goal setting.  The results also point out the potential for future health risks.

VO2 Testing or Vo2max is the ACSM criterion measure of cardiorespiratory endurance.  Measurement of Vo2max involves analysis of oxygen use and carbon dioxide production during exercise of increasing intensity.  These levels are specific to each individual and provide insight as to how the body uses fat and glycogen during increasingly difficult exercise.

During the test, exercise intensity is increased incrementally and data is then collected every 15 seconds. Aerobic and anaerobic thresholds of the individual are measured and VO2max is determined when the test is administered to maximum effort.  When considering the characteristics of gifted endurance athletes, their ability to sustain a high percentage of VO2max is more important than the actual VO2max itself.

Due to the required equipment and expertise required to both administer and interpret the test, Vo2max isn’t logical for a typical fitness setting.  Instead, most fitness centers use a submaximal test and estimate Vo2max, and therefore cardiorespitory endurance, using scientific equations that correlate heart rate to Vo2 during progressive exercise.

References
1.  ACSM’s Guideline for Exercise Testing and Prescription