Strength is the ability of a muscle to overcome or counter external resistance through muscular effort. It manifests itself in the following basic forms: maximum muscle strength (absolute and relative), speed (dynamic), static (isometric) strength and strength endurance (Aganiants, 2001; Ostapenko, 2002; Sports Physiology, 1986).

Under maximum power is meant the greatest opportunity, which the athlete is able to show during maximum voluntary muscle contraction. The maximum strength of a muscle depends on the number and thickness of its muscle fibers. The number and thickness of muscle fibers determine the thickness of the muscle as a whole – the anatomical diameter , that is, the cross-sectional area .

The ratio of the value of the maximum muscle strength to its anatomical diameter is called the relative strength of the muscle . The cross-section of a muscle, perpendicular to the direction of its fibers, is its physiological diameter . For muscles with a parallel direction of fibers, the physiological diameter coincides with the anatomical one. The ratio of the maximum strength of a muscle to its physiological diameter is called the absolute strength of the muscle.

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Velocity strength (explosive) is the ability to exert the greatest strength in the shortest amount of time.

Strength endurance is the ability of a muscle or muscle group to resist fatigue during repeated muscle contractions.

There are certain age periods for the development of strength, when morphological and functional prerequisites are favorable: girls are 9-11 years old, and boys have two periods – 9-12 years old and 14-17 years old (Apanasenko, 1985; Viksne, 1989; Ermolaev , 2001; Fomin, Vavilov, 1991).

Distinguish between maximum static and maximum dynamic force. Maximum static strength is manifested during isometric muscle contraction. The conditions for the manifestation of maximum static force are as follows:

  • activation of all motor units;
  • muscle contraction under the condition of complete tetanus;
  • muscle contraction at rest;
  • mobilization of the activity of the sympathetic nervous system, etc.

Maximum dynamic strength is the strength exerted by an athlete during the maximum voluntary muscle contraction, regardless of time and body weight. Explosive power is provided mainly by:

  • the frequency of impulses at the beginning of contraction and the synchronization of impulses of various motoneurons (intramuscular coordination);
  • contractile properties of muscles (intramuscular coordination);
  • the degree of hypertrophy of fast-twitch muscle fibers, etc.

Power training sessions stimulate sarcoplasmic and myofibrillar hypertrophy (increase in muscle girth) (Sports Pharmacology, 1986; Solodkov, Sologub, 2003). Sarcoplasmic hypertrophy is caused by an increase in the volume of sarcoplasm, the content of mitochondrial proteins in it, metabolic reserves, myoglobin, and the number of capillaries. Slow muscle fibers and fast ones, oxidizable ones, are most prone to such transformations. This type of hypertrophy has little effect on strength gain, but increases the ability to work continuously (endurance).

Myofibrillar hypertrophy is caused by an increase in the volume of myofibrils due to actomyosin .. This significantly increases the strength. An important role in activating the synthesis of protein and nucleic acids is played by androgens and hormones of the adrenal cortex , as well as agents with anabolic action . In all cases, these two types of hypertrophy develop with the predominant development of one of them.


Equipment : hand and back dynamometers.

  • Maximum muscle strength is assessed using different dynamometers. A hand dynamometer (Collin dynamometer) is used to measure the strength of the muscles in the forearm and hand. A bench dynamometer is used to record the strength of the trunk extensor muscles.

All subjects measure the strength of the muscles of the forearm and hand, as well as the strength of the extensor muscles of the trunk, two to three times and record the best result. It should be remembered that the back strength is not investigated in the case of back pain, damage to the muscles of the abdomen, back; in women – during menstruation and pregnancy.

  • Determination of speed strength in subjects is carried out using the following exercises:
  • assessment of the strength of the leg muscles : long jumps from a place, jumping up from a place , the number of squats in 20 s, the number of jumps on the right (left) leg in 10 s;
  • assessment of the strength of the muscles of the arms : flexion and extension of the arms in the lying position for 10 s (number of times), the number of pull-ups on the crossbar for 10 s;
  • assessment of the strength of the muscles of the abdomen and back : flexion of the back from a prone position for 10 s (number of times), lifting the body from a supine position to a straight sitting position (number of times in 10 s), hanging legs forward (number of times per 10 s).
  • The assessment of the strength endurance of the muscles of the arms and the girdle of the upper limbs of the subjects can be carried out while performing pull-ups on the bar or flexion and extension of the arms in support on the uneven bars. For the abdominal muscles, lifting and lowering the body from a supine position is used, and for the muscles of the legs, squats.

The data obtained are entered into a table, compared and conclusions are drawn about the strength capabilities of all subjects.