The research aims to study the effect of eccentric training with 2/1 technique on developing some special physical abilities and lower body asymmetry for taekwondo cadet under 14 years, The researchers use experimental methodology with two groups design (experimental and control) and with pre-post measurements, The research sample was chosen in Purposive method, (18) taekwondo cadet under 14 years were divided as follows (9) taekwondo cadet for the experimental group, (9) taekwondo cadet for the control group, The researchers add eccentric training with 2/1 technique program (8 weeks by two training units per week), the results of this study eccentric training with 2/1 technique has a positive effect on developing some special physical abilities (sprint - muscular power - specific agility - 1RM) and lower body asymmetry for taekwondo cadet under 14 years, The researchers recommend to use eccentric training with 2/1 technique on developing some physical and technical performance, anthropometric characteristics and lower body asymmetry for taekwondo cadet, In addition to directing the results of this study to taekwondo coaches to be able to benefit from its results.