PhD, Associate Professor A.M. Trofimov
Bunin Yelets State University, YelSU, Yelets
Keywords: strength abilities, volitional resource, volitional resource limiting factors.
Background. It is common for modern sport theoreticians to list the following factors of influence on the strength abilities:
- Muscular performance factors including: ratio of white to red (relatively fast and slow contracting, respectively) muscular fibers; activity indices of the muscle contraction ferments; capacity of the anaerobic energy supply mechanisms behind muscular work; physiologically effective size (cross-section) and mass of muscles; and inter-muscular coordination quality;
- Central nervous system (CNS) performance factors including: intensity/ frequency of the muscle controlling affector nerve impulses; contraction/ relaxation process coordination rate; and trophic impacts of the CNS on the muscular functionality;
- Individual mental performance factors including: motivational and volitional contributors; emotional boosters of the intensive/ prolonged/ high-intensity muscular work;
- Biomechanical factors including: postural control in every bodily element; strength of the musculoskeletal system in every element; moving mass factors etc.;
- Biochemical factors i.e. hormonal ones; and
- Physiological factors including peripheral/ central blood circulation/ respiratory/ other system performance indices .
Due understanding of the above factors and their mechanisms of influence on the strength building process is critical for success of any training system.
Objective of the study was to theoretically analyze the factors of influence on the athletic strength building process and the relevant control mechanisms.
Study findings and discussion. Strength trainings generally increase the volume of microfibers and, hence, muscular strength indices. We believe that the additional factor of influence on the muscle contraction strength is the numbers of muscular fibers engaged that may widely vary depending on the physical work intensity and volume.
Studies of the neuromuscular system and muscular performance control mechanisms show that muscle contractions are triggered by volitional impacts on the muscular control centers in the motor segments of the brain . This means that it is the power of the trigger volitional impulse acting on the motor centers that largely determines the muscle strength.
Power of the volitional impulse acting on the motor centers and their response rates are physiologically limited by the maximal permissible CNS excitation index. There are also a few aspects that further hamper the efforts to attain even these natural limits. One of them is the high nervous energy costs claimed by the mental settings for (images of) the movement sequences. Most costly in this aspect are the combined movement sequences including a few elements – like a classical snatch in weightlifting.
The above nervous energy costs claimed by the movement imaging efforts are of limiting effect on the volitional impulse acting on the motor centers. That is the reason why some motor units of the active muscles may still stay idle even when an individual strives to act with maximal strength. The higher is the focus on the movement strength the lower is the attention to the movement technique i.e. the movement imaging component that results in dilution of the movement image and, hence, disorder in the movement sequence with the relevant implications.
Furthermore, as found by the studies, repetitions of some standard movement sequence with multiple reiterations of the movement image help harmonize the mental setting for the movement by stronger links being formed to shape up the image, and the easier setting helps save the nervous energy claimed by the image formation and retention in the consciousness, with the saved energy applicable for excitation of the muscular motor centers. These mechanisms help understand why strength developed in one movement sequence may not be attained in the other even when the same muscle groups are engaged.
Summarizing the above, we have reasons to conclude that one of the key concepts of a training system design in the strength sport disciplines is the high similarity of the training and competitive exercises. Multiple repetitions of competitive routines are known to contribute to competitive progress much in the same way as the hypertrophy of muscular fibers.
Apart from the nervous energy costs claimed by the movement imaging and control process and some other elementary actions to attain the process goals, a few factors still limit the strength abilities including: (1) poor motivation; (2) pain in the key muscle groups and joints engaged in the movements; (3) diseases, injuries, excessive noise, too high or low ambient temperature; and (4) fatigue of the CNS etc.
Pain is associated with physiological limitations including restrictions of the volitional resource since pain is always of paralyzing effect on willpower. Pain may also be associated with the over-excitation of the CNS by the affector impulses . The CNS excitation resource is naturally limited, and the excessive excitation tends to restrict the volitional impulses activating the motor centers. The higher is the pain the lower is the motor centers controllability even when an individual is mentally ready for the action. It should be noted that the negative effects of pain on the individual volitional resource may be mitigated by some psychoactive agents (analgesics, anesthetics, psychotropic compounds, alcohol etc.) and local anesthesia. These agents, however, fail to control the origins of pain and only reduce the affector impulses travelling from the receptors to the cerebral cortex i.e. suppress the CNS excitation components other than directly required for the subject movement sequences.
Furthermore, the total CNS excitation may be increased by the individual emotions (fear, anxiety, frustration, concerns etc.), with high energy claimed by the images associated with the destructive emotions . Contribution of the emotions to the CNS excitation, however, is as limited as in the above case, with the emotions being of the same negative effect of the volitional resource available for the motor centers control. Positive emotions are known to be of the same weakening effect on the latter as the negative ones.
It may be pertinent to emphasize that the above distracting factors and pains are of negative effects on both individual strength and motor imaging quality and, hence, special attention shall be given to the motor techniques to make them as immune to the distracters and pain as possible. Volitional resource mobilized for the movement control purposes tends to sag with the growing fatigue of the CNS that may be due to the shortage of the CNS capacity for the nervous processes servicing needs. That is one of the reasons for the training process efficiency being on the fall when athletes use the post-training rehabilitation time for intensive academic studies or other intellectually challenging activity.
Conclusion. The muscle contraction strength was proved to be determined not only by the number and size of muscle fibers but also the quantity of the directly engaged muscle fibers that may widely vary depending on the situation. It was also found that individual willpower is the key factor in the muscle fibers mobilization process i.e. the degree of the volitional effect on the muscle group control centers. The motor center volitional controls and relevant responses, however, are naturally limited by the bodily physiological barrier i.e. the maximal achievable CNS excitation index, plus a variety of additional natural limitations including the following: imperfect motor skill level; low motivation; fatigue of the CNS; and emotional distractions. The study findings may help athletes and coaches prudently design and manage training systems, identify the reasons for drawbacks of strength building programs and successfully revise them.
- Trofimov A.M. Teoriya psikhicheskogo obraza i assotsiatsiy [The theory of Mental Images and Associations]. Yelets: Bunin YSU publ., 2010, 526 p.
- Kholodov Zh.K., Kuznetsov V.S. Teoriya i metodika fizicheskogo vospitaniya i sporta. Ucheb. posobie dlya stud. vys. ucheb. zavedeniy [Theory and methods of physical education and sports. Textbook for higher ed. est.]. 5th ed., ster.. Moscow: Akademiya publ., 2007, 480 p.
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Objective of the study was to find factors of influence on the athletic strength building process and the relevant control mechanisms. The research methods applied included relevant psychological knowledge collection and systematization method; high nervous activity physiology and motor activity research methods; consciousness introspection method; and empirical data mining method.
The muscle contraction strength was proved to be determined not only by the number and size of muscle fibers but also the quantity of the directly engaged muscle fibers that may widely vary depending on the situation. It was also found that individual willpower is the key factor in the muscle fibers mobilization process i.e. the degree of the volitional effect on the muscle group control centers. The motor center volitional controls and relevant responses, however, are naturally limited by the bodily physiological barrier i.e. the maximal achievable CNS excitation index, plus a variety of additional natural limitations including the following: imperfect motor skill level; low motivation; fatigue of the CNS; and emotional distractions.
The study analyzes the mechanisms of influence of these limiting factors on the athletic strength building process.