Adaptations to Anaerobic Training

The following adaptations have been shown to occur in response to either sprint or resistance type training. In this area there is some disagreement as to whether or not all of the adaptations mentioned below occur to a significant degree in response to other modes of alactic training. Furthermore, the complicated methods for extracting and analyzing muscle tissue may lead to errors in the interpretation of research results.

Creatine phosphate stores
There is some evidence that sprint training may stimulate an increase in the stores of CP within the muscle. However, the increase in total creatine phosphate stores may be due to an increase in muscle fiber size rather than an increase in CP concentration.

If creatine phosphate concentrations were to increase the duration of maximal alactic activity may increase. However, the cause of fatigue during alactic activities is not always a drop in the levels of these energy stores. In this case an increase in CP would be of questionable significance. Furthermore, activities such as jumping and throwing do not utilize all of the available alactic energy stores and would not be expected to benefit from an increase in the amount of ATP or CP within the muscle fiber.

Alactic enzymes
There is some evidence to suggest that the activities of the alactic enzymes (those responsible for the breakdown and resynthesis of ATP and CP) may increase in response to sprint training.

These adaptations might be expected to result in a more rapid release of energy from the phosphagen stores so; as a result, muscular power output may increase. Further evidence is required to conclusively prove whether alactic enzyme activity does respond significantly to training.

Fast twitch muscle fiber hypertrophy.
Undoubtedly the most important adaptation brought about by strength and power training is the preferential hypertrophy of fast twitch fibers, brought about by a proliferation of actin and myosin. In addition to the obvious effects of increasing strength, this adaptation significantly increases the amount of power which can be produced in rapid muscular contractions.

Neural adaptations
Alactic training, especially in the form of weightlifting, often involves maximal or near maximal contractions. As a result it is thought that neural adaptations occur which allow individuals to more fully activate high threshold motor units.

Cardiovascular adaptations
Most alactic training methods have little effect on the cardiovascular system. However, as a result of heavy resistance training the left ventricle wall increases in thickness whilst its volume remains virtually constant.

The stimulus for increased myocardial thickness is the elevated arterial blood pressure which occurs during each set of heavy resistance training.