["Tendon" action of two-joint muscles during human locomotion: transfer of mechanical energy between links in shock-absorbing and push-off phases]. / "Sukhozhil'noe" deistvie dvusustavnykh myshts pri lokomotsiiakh cheloveka: peredacha mekhanicheskoi énergii mezhdu zven'iami v fazakh amortizatsii i ottalkivaniia.

We hale evaluated experimentally the amounts of the mechanical energy transferred by the two-joint muscles between the links of legs during squat vertical jumps and landings after jumping down from a height of 0.5. The experiments have been conducted on file healthy subjects in the course of locomotions. The coordinates of markers attached to the subjects' bodies and the ground reaction forces have been registered. The energy transferred by the two-joint muscles from and to the links forming each joint has been determined by integration of the difference between the power developed in the joint by the control moment and the total power of the muscles serving the given joint. It has been shown, that at squat vertical jump (the push-off phase) the two-joint muscles transfer mechanical energy from the proximal links of the leg to the distal ones: from pelvis to shank (by the rectus femoris m.), and from thigh to foot (by the gastrocnemius m.). At landing (the shock-absorbing phase) the two-joint muscles transfer energy from the distal to proximal links: from foot to thigh (by the gastrocnemius m.), and from shank to pelvis (by the rectus femoris m.). Thus the one-joint muscles of the proximal links compensate for the deficiency in the force developed by the one-joint muscles of the distal links due to the "tendon action" of the two-joint muscles. During push-off, the muscles of the proximal links contribute to increase in the energy of the distal links, and in the shock-absorbing phase, to its dissipation.

[Mechanical energy expenditure on human movement and the anthropomorphic mechanism]. / Mekhanicheskie énergozatraty na dvizhenie cheloveka i antropomorfnogo mekhanizma.

Mechanical energy expenditures of the man and anthropomorphic locomotion machine during movement are compared theoretically. Sources of the mechanical energy affecting movement of human's lower extremity are modelled by 8 muscles, 3 of which are the two-joint muscles. The model of the lower extremity of anthropomorphic locomotion machine is moved by joint moments. It was shown that in the same movement the model of the human lower extremity can spend less mechanical energy than that of the model of the anthropomorphic locomotion machine. It is caused by the presence of two-joint muscles in the first model. Such an economy of mechanical energy expenditures realized by the two-joint muscle is possible at simultaneous execution of three conditions: 1) signs of the muscle powers, which are produced by that muscle at both joints, are opposite; 2) moments produced by that muscle at each of both joints have the same direction with the joint moments at these joints; 3) one-joint antagonistic muscles are not active. An expression which makes it possible to estimate the mechanical energy savings by the two-joint muscles during humans' movement was developed.

[A quantitative assessment of the "tendon" action of two-joint muscles]. / Kolichestvennaia otsenka "sukhozhil'nogo" deistviia dvusustavnykh myshts.

Two-joint muscles are able to transmit mechanical energy between the links of the body having no common joint ("tendon action" of the muscles). It is proposed to calculate difference between control moment power in a joint and the sum of powers developed by all muscles serving this joint in order to determine the direction and rate of mechanical energy transfer through the two-joint muscles. It was shown that in the shock-absorbing phase of support in running two-joint muscles the energy transfers from distal to proximal links (from foot to thigh, and from shank to pelvis), in take-off phase-from proximal links to distal ones (from pelvis to shank, and from thigh to foot).

[A model for determination of muscle forces in a given movement of man]. / Model' dlia opredeleniia myshechnykh sil v zadannom dvizhenii cheloveka.

A model of a muscular-skeletal system of a man for determination of muscle forces knowing kinematics of the body is elaborated. Forces exerted by the muscles of the lower extremities in normal walking are presented (planar model of a leg, 8 muscles). The forces found were compared with corresponding EMG-activity of muscles.

[Arms of the forces and elongation of the muscles of the lower extremities at various values of the joint angles]. / Plechi sil i udlinenie myshchts nizhnikh konechnostei pri razlichnykhzhacheniiakh sustavnykh uglov.

Basing on the literature data, regressive equations have been calculated for predicting arms of the forces and for elongating 9 muscle groups of the lower extremities according to the known values of the angles in the joints.

[Biomechanics and movements of the body after 120-day antiorthostatic hypokinesia]. / Biomekhanika tela i dvizhenii liudei, podvergshikhsia 120-sutochnoi antiortostaticheskoi gipokinezii.

This paper presents data on body parameters (weight and circumference) and walking biomechanics after 120-day head-down tilt. The exposure leads to changes primarily in the anti-gravitational muscles. They are assumed to be caused by relative changes in the fat and muscle components. Head-down tilt also produces changes in the kinematic parameters of the walking process, the shape of support reactions, and losses in the cost-efficiency of the walking process.

[Study of the mass-inertia characteristics of human body segments by the gamma scanning method during 6 months of hypokinesia]. / Issledovanie mass-inertsionnykh kharakteristik segmentov tela cheloveka metodom gamma-skennirovaniia v usloviiakh 6-mesiachnoi gipokinezii.

It was found that there was a distinct redistribution of body masses in 18 test subjects exposed to 6-month hypokinesia. Six of them (who did not exercise) showed losses of muscle mass (primarily antigravity muscles) and gain of adipose mass, and 12 test subjects (who exercised as a countermeasure against hypokinetic effects) displayed insignificant losses of muscle mass and significant gain of adipose mass.

[Modeling human spatial movement]. / Modelirovanie prostranstvennogo dvizheniia cheloveka

The problem of determining biodynamical characters of human locomotion in space is considered. The method for calculating the forces and the moments in joints for 15-link model of support-motive apparatus of man is discussed.