Since the children were born,their yin-yang balance in their body began.Children’s yin-yang balance is the yang taken a dominant role in yin-yang balance."Shaoyang for the pivot" is the core of "Shaoyang doctrine"theory.It is very proper to explain the children’s yin-yang balance with the state of continuous transporting and changing by the theory of "Shaoyang for the pivot".Along with "mutual promotion of growth between yin and yang",new yin yang balance continuously replace the old one,constructing children’s basic physical characteristic of "full of vigor and vitality,rapid development;viscera is delicate and organs function is not perfect".Meanwhile it is very proper to explain the pathological characteristics "easy incidence,rapid changing;viscera qi clean and full of spiritualism,easy rehabilitation".So "Shaoyang doctrine" can cover "pure yang doctrine" and "immature yin and yang theory".

Objective: To explore the factors, characteristics and imaging manifestations of ankle joint injury in amateur marathoners (no formal training and no marathon career). Methods: From December 2018 to March 2019, the amateur marathon runners in Guangdong Zhuhai had been recruited as research subjects according to the study inclusion and exclusion criteria. The questionnaires were used to collect relevant data, and the subjects underwent MRI scans of the ankle joint. The ankle joint special phased array coils were used to perform fast spin echo sequence (TSE) coronal T₁WI and proton density-weighted fat-suppression sequence (PDWI-FS). Axial, coronal and sagittal scans, three-dimensional-double echo steady-state sequence (3D-DESS) and three-dimensional variable flip angle fast spin echo sequence (3D-SPACE) scans were also acquired. The results of the examination were independently analyzed by two radiologists (5 and 17 years of work experience, respectively) on the ligament, tendon, bone marrow and ankle joint injuries. When they had inconsistent views, the diagnosis provided by the third radiologist (27 years of work experience) was considered a final diagnosis. The relationship between ankle injury and different running postures, the number of participating in marathons and training intensity was analyzed, and the independent sample χ² was used for statistical analysis. The consistency of two radiologists was tested by Kappa test. Results: According to the inclusion and exclusion criteria, 39 subjects were included, with 64 ankles totally, 35 right ankles and 29 left ankles. MRI showed that (1) Ligament injuries: 28 ankles were anterior talofibular ligament injuriy;50 ankles were posterior talofibular ligament injury; 60 ankles the calcaneofibular ligament injuries and 54 ankles were deltoid ligament injuries, without complete injury. (2) Tendon sheath effusion and injuries: peritendinous effusion was common, with 47 flexor hallucis longus tenosynovitis, 49 posterior tibialis tenosynovitis, 37 flexor digitorum longus tenosynovitis, 7 peroneus longus tenosynovitis and 5 peroneus brevis tenosynovitis. (3) Synovitis effusion: 43 posterior ankle synovitis and local effusion. (4) Others: cartilage injury in 2 ankles, bone marrow edema in 8 ankles, and among them stress fracture in 2 ankles. The two radiologists had good consistency with the Kappa value of 0.91. Regarding the running posture, the incidence of ligaments injuries was obviously higher in those who landed on the hind foot than in those landed on front and middle foot,and the difference was statistically significant(P=0.013, χ² value was 6.191).The incidence of tendon injuries was higher in those who landed on the front middle foot than in those landed on the hind foot, and the difference was statistically significant (P=0.029, χ² value was 4.775). Those with larger training (training running ≥300 km/month) had significant ankle injury (P=0.005, χ² value was 7.844). Conclusion The MRI features of ankle joint injuries in amateur marathon volunteers are related to different running postures and training intensity.