P&P#75

P&P 79: Motor Qualities and Fitness Components

The existence and definition of discrete motor qualities and fitness components such as speed, strength, muscular endurance and cardiovascular endurance on the basis of physiological specificity may not be as clear-cut as is generally implied.

The world of sports is replete with different methods of testing, measuring and prescribing exercise on the basis of motor qualities such as strength, speed, flexibility and power and metabolic or physiological qualities such as 'aerobic' (cardiovascular) and 'anaerobic' fitness. These qualities are usually regarded as the fundamental components of the situation-specific quality known as 'fitness', yet their validity and discreteness is rarely questioned.

Complex machines and procedures (incorrectly called 'protocols') have been devised to assess these qualities separately from one another, as if each one of these qualities or factors is entirely independent of one another. Thus, we have tests for V02 max, anaerobic power, isokinetic strength, power and muscle endurance, vertical jumping explosive power, anaerobic capacity, aerobic power and so on (e.g. see MacDougall et al 'Physiological Testing of the Elite Athlete' for an overview of such tests) - yet it is extremely rare to find any text which examines the interaction or interdependence of these so-called discrete fitness components.

Now and again you will find someone who criticizes the use of terms such as strength-speed (power under heavy loading), speed-strength (power with light loading), strength-endurance (static or dynamic muscle endurance), strength- skill (identified by Diachkov, 1961) and skill-endurance, apparently because it is impossible to identify specific metabolic or neuromuscular processes which characterise each of these factors. However, on the average, most fitness factors (certainly those appearing in college textbooks or used in sports science laboratories) are accepted alongside definitions of mass, length and time as fundamental units for assessing human 'fitness'.

We have to remember that motor qualities such as strength and neuromuscular skill are involved in most tests of other presumably discrete fitness qualities such as power, cardiovascular endurance, muscular endurance and so forth. For instance, very low levels of strength in the lower extremities will adversely affect one's ability to generate 'cardiovascular' endurance or 'aerobic power' on a treadmill or cycle ergometer. Similarly, low levels of strength can decrease one's ability to produce maximal power in 'specific' power tests.

The generation of power or strength on isokinetic or other dynamometers is also fraught with similar problems. If one is testing for maximal power or strength, then the muscles are being called upon to perform at their limit over specific periods of time. Now, if time is involved in measurement, then the issue of muscular or other types of endurance enters the picture, since endurance may be defined as the ability to work for a prolonged period under specific conditions of loading and speed. So, if limit testing (1RM or x-RM testing, where x is small) is carried out, then the results could be affected by the subject's level of static or dynamic muscle endurance.

In fact, this is one of the major problems confronting the production of any torque-time, torque-joint angle, power-time, force-velocity and related biomechanical curves - we cannot be sure of the extent to which static, quasi- static or short-duration muscle endurance is influencing the results. This means that it is difficult to talk with any conviction about the variation of strength, torque or power as a result of changes in mechanical efficiency (leverage etc), metabolic function, neuromuscular (skill) efficiency, motivation (with its major effect on muscle fibre recruitment), pain and perception of pain and effort, muscle endurance or fatigue. This justifiably leads some critics to question the validity and relevance of many 'standard' strength, power and related curves.

Are we, therefore, really justified in accepting the traditional components of fitness or motor capability as religiously as we do? Do we have to discard some or all of them (and then wonder where on earth we should begin or continue from this cleaned slate?), do we redefine them or do we simply accept all of them with all their imperfections and errors? Do we archive all the biomechanical performance curves and dynamometers as museum pieces and rewrite the textbooks with warnings about the limited value of physiological and biomechanical testing in modern measurement? Do we accept that these factors are essentially a matter of descriptive convenience that have played a useful role in sports science for many years and continue to use them without much further ado?

Do we accept that all of these tests, like IQ ('Intelligence Quotient') tests, are simply a matter of definition based on the composite interaction of other more fundamental factors which we are really quite unable to define accurately? Probably even more fundamental to the entire issue is the question as to whether or not discrete and independent fitness factors actually exist. If this is the case, then functional testing of performance in a given motor activity or sport may then be the only valid way of assessing changes associated with specific regimes of training or rehabilitation.

After all, in actual sporting situations, how can we state with such conviction that aerobic and anaerobic processes are each responsible for a certain precise percentage of the energy required in a given sport (e.g. see the renowned metabolic energy tables in Fox & Mathews 'Interval Training for Sports and General Fitness')? How can we justifiably separate the 'aerobic' processes involved with locomotion from the 'anaerobic' processes involved with local muscle contraction and postural control in any given sport or activity?

This would then imply that many of the costly devices and procedures currently being used in our laboratories, training facilities and rehabilitation centres may generally be a waste of time, money and effort. Consequently, many of the erudite papers written in learned journals might have to be re-examined carefully for validity and applicability! Clearly, the ramifications of this P&P are vast and warrant extensive comment from as many of you as possible. We look forward to your input on this extremely important issue.

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