Abstract: The paper is to explore the muscle strength characteristics of male elite long jumpers' lower extremity and to compare the differences between the master-group and first-grade group. Isokinetic dynamometer( IsoMed 2000 from Germany) is adopted to measure the muscle strength for the subjects' (seven master group and eight first-grade athletes)hip , knee and ankle joint at the flexion and extension mode. 5 repeated maximum isokinetic contractions with an angular velocity of 60?/s at the angular velocity of 240?/s are measured 25 times. Results(1) The master group show their advantages in their ankle flexors' absolute force and explosive power in the hip , knee extensors and ankle flexors; (2) The specific value range of the two groups shoe no significant differences in their lower limb joint flexor and extensor, with the hip range ratio being 0.63-0.82, knee, 0.56 -0.64, ankle, 2.69 -5.53; (3) All the subjects' knee and ankle joint muscle endurance should be strengthened.

Key words: Long jump, Excellent athletes, Isokinetic testing, Lower limb joint muscle strength