Biochemical Foundations of Human Vital Activity - Volkov, N. I., & Nesen, E. N. 2000

Biochemistry of Sports
Biochemical Control in Sports
Objects of Study and Key Biochemical Indicators

The objects of biochemical research include exhaled air and biological fluids—such as Blood, urine, saliva, and sweat—as well as Muscle tissue.

Exhaled air is a primary object of study when investigating METABOLISM/26.html">Energy Metabolism processes within the body and the utilization of specific Energy Sources to fuel muscular activity. It is used to measure the volume of oxygen consumed and carbon dioxide exhaled. The ratio of these two parameters serves as an indicator of the intensity of energy metabolism and the relative contributions of anaerobic and aerobic pathways to ATP resynthesis.

Blood is one of the most critical samples in biochemical research because it reflects all metabolic shifts occurring in the body's tissue fluids and Lymph. Changes in the composition of whole blood or its liquid fraction, plasma, provide insight into the homeostatic state of the body's internal environment or how it shifts in response to physical activity (Table 48).

Since many assays require only a small volume of blood (0.01–0.05 mL), it is typically drawn from the ring finger or the edge of the earlobe. Following physical exertion, blood collection is recommended 3–7 minutes post-exercise, which corresponds to the peak of biochemical alterations.

Class="center">TABLE 48. Main Cell/6.html">Chemical Components of whole blood and plasma in a healthy adult

Physical exertion, environmental stressors, pathological metabolic alterations, or the administration of pharmacological agents can significantly modify the levels of specific blood components. Consequently, blood analysis enables the assessment of an individual's health status, fitness level, adaptation processes, and more. In recent years, due to the risk of HIV transmission, blood handling requires strict adherence to all established safety precautions.

Urine reflects, to a certain extent, the function of the Kidneys—the body's primary excretory Organs—as well as metabolic dynamics across various organs and Tissues. Therefore, tracking shifts in its quantitative and qualitative composition allows researchers to evaluate specific metabolic pathways, excessive nutrient intake, and disruptions in homeostatic regulation, including those related to muscular activity. The kidneys excrete excess water, numerous electrolytes, metabolic intermediates and end products, hormones, Vitamins, and xenobiotics from the body (Table 49). The normal daily urine volume (diuresis) averages about 1.5 L. Collecting urine over a 24-hour period introduces certain practical challenges for researchers. Alternatively, urine can be collected in fractionated portions (e.g., every 2 hours), while precisely recording the samples obtained before and after physical exertion. Urine is not a reliable sample following short-term training sessions, as collecting a sufficient volume immediately afterward is exceedingly difficult.

TABLE 49 Chemical composition of urine in a healthy adult

Under various functional states of the body, chemical substances atypical of normal physiology—such as glucose, protein, ketone bodies, Bile pigments, and blood formed elements—may appear in the urine. Detecting these substances is useful in the biochemical Diagnosis of certain medical conditions and in sports practice to monitor training efficiency and an athlete's health status.

Saliva is typically analyzed alongside other biochemical samples. Assays of saliva generally measure electrolytes (Na and K), enzyme activity (amylase), and pH. Some researchers suggest that because saliva has a lower buffering capacity than blood, it may more sensitively reflect changes in The Human Body's acid-base balance. However, saliva is not widely used as a research sample because its composition depends not only on physical exertion and associated shifts in interstitial metabolism, but also on feeding status (i.e., whether the sample is collected in a fasted or fed state).

Sweat is occasionally of interest as a research sample. The volume required for analysis is collected using cotton undergarments or a towel, which is then soaked in distilled water to extract the various sweat components. The extract is vacuum-evaporated and subjected to laboratory analysis.

Muscle tissue is a highly informative sample for the Biochemical Monitoring of muscular activity, though it is rarely utilized because obtaining a specimen requires a needle biopsy. This Procedure involves making a small incision in the Skin over the muscle of interest and using a specialized biopsy needle to harvest a small tissue sample (2–3 mg). The sample is immediately frozen in liquid nitrogen and subsequently analyzed for Structural and Biochemical properties. Assays measure the concentrations of contractile Proteins (Actin and Myosin), myosin ATPase activity, energy reserve indicators (ATP, Glycogen, and creatine phosphate levels), energy metabolism byproducts, electrolytes, and other substances. These values reveal the composition and functional activity of the Muscles, their energy potential, and the metabolic alterations induced by acute exercise or long-term training.

Biochemical evaluations in sports practice rely on the following key metrics and parameters:

✵ energy substrates (ATP, PCr, glucose, free fatty acids);

✵ energy metabolism Enzymes (ATPase, creatine kinase, cytochrome c oxidase, Lactate dehydrogenase, etc.);

✵ intermediate and End products of carbohydrate, lipid, and Protein metabolism (lactic and pyruvic acids, ketone bodies, urea, creatinine, creatine, uric acid, carbon dioxide, etc.);

✵ blood acid-base balance indicators (blood pH, partial pressure of CO₂, buffer base reserve or base excess, etc.);

✵ metabolic regulators (enzymes, hormones, vitamins, activators, inhibitors);

✵ minerals in biological fluids (e.g., bicarbonates and phosphoric acid salts measured to determine blood buffering capacity);

✵ total protein content alongside the concentration and ratio of plasma protein fractions;

✵ anabolic Steroids and other prohibited performance-enhancing substances (doping agents), the detection of which is the primary objective of anti-doping control.