Support: Changes in the structure and function of the foot were known to make walking a little different on the cosmonauts' return to Earth. For four hours a day, Cuban cosmonaut Arnaldo Tamayo Méndez donned special shoes named Dome-Sand-501 in an attempt to determine the cause of the changes in the movement of their feet after a period of prolonged weightlessness. These results would allow advances to be made in the design of more appropriate footwear to preserve the structure of the foot in weightless conditions.
Stress: Scientists at the Cuban Institute of Endocrinology and Metabolic Diseases prepared this experiment, aimed at recognizing whether the effects of psychological stress experienced during mission preparation, the launch of the flight, in weightlessness, and over many continuous working hours, caused hormonal changes in an individual. The experiment was based on an analysis of blood and urine samples taken from the crew before departure and after their return.
Anthropometry: An experiment conducted to determine changes in the levels of skeletal muscle structure in cosmonauts. The tests were performed through a special instrument known as the Calibrómetro Cosmos-726, designed and built by Cuban specialists, which assessed the adipose tissue and the stimulation of body fat.
Blood Circulation: This experiment sought to determine the impact weightlessness has on the human circulatory system. Tests had been carried out in previous flights and were repeated during this mission using a Chibis suit, a below-the-waist reduced-pressure device. Crew members completed exercise protocols wearing the Chibis to provide gravity-simulating stress to the body's cardiovascular/circulatory system and re-establishing the body's orthostatic tolerance after extended periods of microgravity. Negative pressure on the legs causes blood to accumulate in the lower extremities, which is the case in a gravity environment. Orthostatic intolerance has been a frequent complaint in humans returning from long-duration space flights.

Hatuey: This experiment was an attempt to learn more about the effects of weightlessness on the process of cell division in the living organism. Yeast was sent aboard and observed aboard Salyut 6 for its process of cell reproduction.

Immunity: Scientists analyzed blood samples before and after the flight to determine what happens to the human immune system and the concentration levels of antibodies and other proteins and minerals under conditions of weightlessness.

Balance: The loss of water, fat and minerals in cosmonauts was studied during their stay in space. In this case the study became more interesting as Arnaldo Tamayo Méndez came from a tropical island country and savanna, indicating a very different situation to that in previous experiments with Soviet crew, or other countries in the area near the USSR.

Sugar: This experiment studied the growth of a single crystal of sucrose in weightlessness.

12th expedition to Salyut 6. 7th international crew. Carried Intercosmos cosmonaut from Cuba. The Soyuz 38 docking occurred in darkness. As the spacecraft approached Salyut 6, the crew on the space station could see only its “headlights.” Ryumin filmed ignition and operation of the transport's main engine. Arnaldo Tamayo Méndez of Cuba and Soviet cosmonaut Yuri Romanenko docked without incident.
The crew of Soyuz 38 carried out nine experiments:
Cortex: Destined to study the electrical activity of the brain to certain stimuli and during spaceflight. Scientists wanted to analyze how brain activity was modified in space and whether or not these changes were reversible after returning to Earth. A special helmet was made for each cosmonaut in which silver electrodes were installed, as well as a headset, sound and light stimulators, amplifiers to stimulate brain electrical activity and a tape recorder.