Homeostasis and Adaptation
The human body has numerous regulatory mechanisms that exert control of its internal environment to promote survival. If the fluid content of the body diminishes, we feel thirsty and drink more. If the core temperature of the body rises, we are stimulated to take measures to cool ourselves down and return our core temperature to normal. If our blood sugar level falls, we begin to feel hungry and our motivation to eat is increased. These examples provide a basic understanding of homeostasis, the tendency for all living organisms to regulate internal conditions.
The internal environment of the body is subjected to stress when we exercise, and the greater the intensity of the exercise the harder the homeostatic systems have to work. There are visible signs of these mechanisms at work when we exercise but a great deal more is not visible and not easy to understand. As coaches and athletes, we rely therefore on scant knowledge of unseen homeostatic processes and as a result it is difficult to set training programs that deliver an optimal level of stress.
If exercise stress is frequent, systematic and consistent in nature, as when we engage in a well-designed and purposeful training program, the body’s homeostatic mechanisms promote adaptation to the stress experienced. Indeed, this adaptation is the objective of the training process and therefore in devising a training program we must have in mind the specific nature of the adaptation desired. However, if the exercise stress is infrequent, inappropriate or unsystematic in nature then the performance gain we seek may not occur or occur more slowly than we would like, or even a loss of performance occurs (a process referred to as maladaptation).
In Olympic Weightlifting, the end goal of adaptation process is that athletes will develop an exceptional ability to:
- Apply force to a barbell in a very specific manner to cause sufficient vertical displacement (height from the ground),
- Move with exceptional speed under the bar, and
- Adopt a body position that prevents the bar from falling back to the ground and to the satisfaction of the referees.
The adaptation needed to develop the above abilities is physiologic and psychological in nature and it should be borne in mind that the brain is at the centre of this adaptation process. It should be appreciated that all movement occurs as a result of activity within the neurons of the central and peripheral nervous system. Therefore, adaptation to the stresses induced by sport training should be viewed as a holistic process and that a focus on strength as purely a physiologic phenomenon is an error.
The achievement of excellence requires an athlete to be in an optimal state of physiologic and psychological readiness, and assisting athletes to obtain this goal is the art and science of coaching. Weightlifting coaches, particularly those who work with high performance athletes, have a need to make frequent, if not daily, decisions about an athlete’s training load. However, it is most unlikely that such decisions, even among experienced coaches, are without some degree of error. It is very difficult for a coach to determine in advance whether a particular training load will be adaptive or maladaptive and at what point maladaption begins as a result of chronic training overload (Kenttä & Hassmén, 1998).
Therefore, the accumulation of knowledge of how the body adapts to exercise is an important asset in determining training load and helps to minimise errors that lead to injury and overtraining. It is useful therefore to have an appreciation of:
- Changes in bone density
- Muscle anabolism and hypertrophy
- Muscle fibre composition and interconversion
- Muscle innervation
- Endocrine response to training
- Energy metabolism
The high intensity exercise experienced in Weightlifting training stresses the internal environment of the body and as a result of homeostatic mechanisms there is stimulus for adaptive change.