<bold>Introduction</bold>. The aim of this study was to determine the dynamics of changes in selected motor abilities of javelin throwers and to determine predictors of javelin throw distances. <bold>Material and methods</bold>. Research material included the results obtained from a group of 60 competitors from the Silesia Region of Poland, aged 14 - 15 years. In order to answer the research question, the following statistical analysis were employed: Pearson's linear correlation coefficients, vectors R0 and R1, time series analysis, distributed lag analysis and Almon distributed lag analysis and coefficient of concordance φ2<bold>Results</bold>. The correlation analyzes allowed for a selection of two variables for further analyses: specific strength of arms and trunk (SSAT) and specific strength of shoulders girdle and trunk (SSGT). Calculated indexes revealed that the level of SSAT showed a constant upward tendency (+15%). The highest rise in SSAT level was recorded in the 4th and 5th quarter (+9%). The level of SSGT showed an upward tendency nearly (+6%). In this case, the highest rise was observed in the 7th and 8th quarter (+4.5%). <bold>Conclusions</bold>. The standardized regression analysis revealed that the variable of specific power of arms and trunk (SOBT) is the most important predictor for javelin throw distance with a full approach run.