|（1.Department of Physical Education，Shenzhen University，Shenzhen 518060，China；2.Guangzhou Sport University，Guangzhou 510500，China)
Abstract: By means of ultrasonic technology, the authors observed the characteristics of changing of the Achilles tendon shape structure of amateur runners before and after marathon running, and what changes will occur to the Achilles tendon structure of marathon runners of different genders before and after running, and explored the mechanism of the Achilles tendon structure’s acute effect on marathon running. The authors selected 10 male testees with an age of (35.30±7.15), a height of (1.76±0.05) m, and a weight of (68.70±5.62) kg, and 8 female testes with an age of (25.50±4.63), a height of (1.63±0.06) m, and a weight of (52.88±4.88) kg, and by means of ultra-sonic imaging technology, observed the changing of such indexes as Achilles tendon length, soleus muscle length, Achilles tendon cross-sectional area and Achilles tendon thickness, and revealed the following findings: after mara-thon running, the Achilles tendon lengths of the male and female amateur runners increased, and the differences be-fore and after running were all statistically significant (for the males: P=0.037<0.05; for the females: P=0.020<0.05), the differences in Achilles tendon lengths relative to shank lengths were also statistically significant (for the males: P=0.039<0.05; for the females: P=0.022<0.05); after marathon running, the Achilles tendon cross-sectional areas of the male and female amateur runners decreased, and the Achilles tendon cross-sectional area differences before and after running were statistically significant (for the males: P=0.044<0.05; for the females: P=0.032<0.05); before and after running, the differences in such indexes as soleus muscle tendon lengths, soleus muscle tendon lengths relative to shank lengths, Achilles tendon thickness, and Achilles tendon thickness relative to BMI with respect to the male and female marathon runners were not statistically significant. The authors concluded that marathon’s acute effect mainly shows Achilles tendon length increase and Achilles tendon cross-sectional area decrease, and suggested that marathon runners intensify the lower limbs’ gastrocnemius and soleus muscle tendon structures via strength training, while carrying out stamina training, thus avoiding the damage caused to muscle tendon by Achilles tendon’s acute effect.
Key words: Achilles tendon；shape structure；ultrasonic imaging technology；marathon running