Science for practice

Metabolic Shifts in Weightlifters under Training Loads

K. A. Korovnikov, N. I. Yalovaya, G. A. Azizbekyan, Yu. A. Matveyev, Institute of Nutrition, USSR Academy of Medical Sciences, Moscow; V. S. Belyaev, R. N. Volkhovsky, MOGIFK

English summary of Tyazhelaya Atletika. Ezhegodnik 1984 (Moscow: Fizkultura i Sport, 1984), pp. 63–66: the text is paraphrased, not translated; data tables are given in full with English labels.

Adaptation to heavy loads restructures metabolism so that functional systems work more economically and resist extreme stress. But sharp metabolic shifts after loads of great volume and intensity, and slow recovery, can limit work capacity and training effect, so it matters to understand metabolism and how recovery-related processes can be influenced. The study covered the metabolic status of 43 weightlifters aged 19–22, body weight 55–113 kg.

Metabolic findings

Small loads (2–5 t, mostly at 65% of maximum) and medium loads (5–8 t at 75–85%) caused no significant change from relative rest in urinary total nitrogen, urea, amino nitrogen and creatinine. Under large loads (over 8 t, with high-intensity exercises of 90–100%) their renal excretion rose considerably (Table 1). Creatinuria (0.01–0.019 g/h) appeared in 70% of athletes and proteinuria in 32%. Sweat collected from the upper body during a 1.5-hour session held about 0.4 g of total nitrogen.

Table 1. Effect of large training loads on urinary excretion of nitrogen end products (x̄ ± S_x̄)

* Difference from baseline significant (p < 0.05).

As load volume and intensity grew, daily urinary potassium rose markedly and sodium fell, while calcium and phosphorus did not change significantly (Table 2). The more skilled and trained the athlete, the smaller the potassium and sodium shifts.

Table 2. Effect of training loads of different volume on daily urinary excretion of potassium, calcium, sodium and phosphorus (x̄ ± S_x̄)

* Difference significant (p < 0.05).

Large loads raised the need for vitamins B₁, B₂, PP, B₆ and ascorbic acid (Table 3). Markers of strain, fatigue, recovery and adaptation (urinary catecholamines, ketone bodies, acid mucopolysaccharides, serum urea, acid-base state) sometimes showed incomplete recovery from earlier heavy loads: metabolic acidosis, raised morning serum urea, low urinary dopamine and DOPA (reflecting sympathoadrenal reserve), and high urinary ketone bodies and acid mucopolysaccharides.

Table 3. Effect of large training loads on urinary excretion of vitamins and their metabolites

Diet

These shifts reflect metabolic strain from heavy physical and nervous-emotional stress, but they and the speed of recovery also depend partly on nutrition (N. I. Yakovlev, 1957; A. A. Pokrovsky, 1975; V. A. Rogozkin, 1975; A. A. Minkh, 1976). The lifters' actual diet did not always meet rational requirements and was often unbalanced. Protein, fat and carbohydrate stood at 1 : 1.2 : 1.7 instead of the recommended 1 : 0.8 : 4. Protein, 14% of energy, was below the 16–18% needed under heavy loads (Schneider, 1979); methionine and several non-essential amino acids were deficient, apparently because animal protein (80–90%) dominated. Fat was excessive, 46% of energy, with a low polyunsaturated to saturated ratio, while carbohydrate was extremely low at 40%.

Potassium, sodium and calcium were well below levels recommended for athletes (Pokrovsky, 1975; N. N. Yakovlev, 1975; Schneider, 1979); phosphorus was adequate. Coenzyme-forming vitamins (thiamine, niacin, pyridoxine, pantothenic acid, folacin, biotin) were at the lower limit of the adult norm, and ascorbic acid extremely low: 12.5±0.9 mg per 1000 kcal against 35.

This imbalance probably contributed to the metabolic changes. B vitamins and ascorbic acid were short through low intake and poor absorption, owing to disturbed ratios among vitamins and other nutrients. Excess fat with too little carbohydrate raised urinary ketone bodies in some athletes (80–180 mg/day against 20–50). A poor potassium to protein ratio (V. D. Grebenyuk, 1975; G. A. Azizbekyan, 1981; Anand et al., 1974; Margen et al., 1974) may explain the higher potassium losses.

A specialised food product

Faster metabolic recovery and sustained work capacity under heavy loads require above all correct nutrition. Specialised foods help: easily digested, calorie-dense, compact, and adjustable to the athlete's expenditure. Ordinary foods in amounts that meet protein needs, with several sessions a day, give a large, slowly digested meal, which can cause discomfort, stomach heaviness, laboured breathing and dyspepsia during barbell work (Centenzo, 1976; Rogozkin, 1973; K. A. Laricheva, Yalovaya and others, 1978).

From these findings the Institute of Nutrition developed an acidophilic specialised product to speed recovery after heavy loads. Each 100 g contains 30–35 g protein, 45–50 g carbohydrate and 10–15 g fat. Its amino acids are balanced, its polyunsaturated to saturated fatty acid ratio is a physiological 0.5, and its carbohydrates include glucose, fructose, sucrose, lactose, maltose, dextrins and starch, with organic acids and many vitamins and mineral salts. Taken on top of the usual diet, it raised protein and carbohydrate and added vitamins (C, B₁, B₂, B₆, PP) and minerals (K, Na, Ca, P, Mg, Fe, Zn, Cu and others), benefiting metabolic status, well-being and work capacity.

Taking 100 g daily activated anabolic nitrogen processes, lowered renal excretion of amino nitrogen and creatine, eased strain in potassium, sodium, calcium and phosphorus metabolism, reduced potassium loss and improved vitamin status. Biochemical tests showed faster recovery from earlier heavy loads: lower excretion of ketone bodies and mucopolysaccharides, lower morning fasting serum urea, and smaller, faster-recovering acid-base changes. Training became more effective and results grew. Lift times recorded with an electronic laser device (R. N. Volkhovsky, 1979) in six intensity zones (60, 65, 75, 85, 90 and 95% of best result) were shorter in every zone than in the control group, by 0.7–1.5 ms in the snatch and 0.7–1.1 ms in the clean and jerk.

The metabolic status of athletes should therefore be monitored during heavy loads, and metabolic shifts corrected promptly through nutrition.