Objective: preparing exercises for the third intensity zone for strength and speed for the legs, and identifying their effect on some physiological and biochemical indicators for (the level of lactic acid concentration, the concentration of sodium bicarbonate, the concentration level of (potassium K+) and (sodium Na+) in the blood, and the number of breathing times (RF) Research methodology: the experimental research method was adopted by designing the experimental and control groups on a sample of Army Sports Club players amounting to (16) players, deliberately selected (100%) from their community using a comprehensive enumeration method, and then divided into two groups of equal number, After determining the tests for physiological and biochemical indicators, these exercises were experimented with, adopting the use of different training tools, by regulating the training load for each player at an intensity of (85%) to (95%), repetitions of (5-10), groups of (3-5), and the duration of the rest periods. Result: ha applying the third intensity zone exercises for strength and speed in the legs helps reduce the level of lactic acid concentration and increase the concentration of sodium bicarbonate in a balanced manner and helps improve the concentration level of (potassium K+) and (sodium Na+) in the blood in Blood in handball players helps reduce the number of respirations (RF) after exertion, Conclusions: Applying exercises in the third intensity zone for strength and speed in the legs helps reduce the level of lactic acid concentration and increase the concentration of sodium bicarbonate in a balanced manner in the blood of handball players.
