Abstract: Object: To provide the best training cycle and mechanism for the intermittent swimming training.Methods: The male SD rats were randomly divided into blank control group(K, n=6), single cycle/week training group (one round of training with small, medium and large load, T1, n=42), double cycle/week training group (T2, n= 42), triple cycle/week training group (T3, n= 42).After oneweek of swimming training, indexes of blood, kidneys, measured CRE, SOD, MDA, Ca²⁺-ATP were sampled respectively from K group in quiet state, and group T1, T2 and T3 at seven different times(T₀、T₁₂、T₂₄、T₃₆、T₄₈、T₆₀、T₇₂) after motion.Results: The CRE content in rats bloodincreased significantly(P<0.05)after the single cycle of training;MDA content in kidney tissue rose dramatically; Ca²⁺-ATPase content at T₀ and T₁2 dropped significantly(P<0.05).After double cycle of training,Ca²⁺-ATPase content in kidney changed obviously at every phase, going up significantly at T₁₂ and T₂₄ and dropping obviously at T36. SOD in kidney tissue went down immediately, up significantly at T₂₄ and T₃₆,and back to normal at T₆₀;CRE in blood increased immediately, therefore the best time/phasefor renalfunction recovery is in the period from T₄₈ to T₆₀.After the triple cycle of training, CRE content in the blood increased significantly, going up obviously and down at T₂₄ and T₃₆,and back to normal at T₇₂;SOD in kidney tissue presented sharp drop immediately; as compared with Group in quiet state, MDA content went up significantly at every phase, and back to normal at T₇₂;Ca²⁺-ATPase content in kidney dropped significantly at T₁₂, T₂₄, and T₄₈, therefore the best time/phasefor renalfunction recovery is in the period from T₆₀ to T₇₂.Conclution: After T2 training , the best time/phasefor renal function recovery is in the period from 48 h to 60 h; After T3 training , the best time/phasefor renal function recovery is in the period from 60 h to 72 h.

Key words: Kidney, Cycle Training, Law of Recovery, Aerobic Exercise, Rat