SUMMARY
The purpose of the study was to obtain regression models of immediate and delayed training effect of strength loads in boys aged 8 years, based on a full factorial experiment.Materials and methods. The study participants were 48 boys aged 8 years. The experiment was performed using a 22 factorial design. The study materials were processed by the IBM SPSS 22 statistical analysis program. The study examined the impact of four variants of strength load on the immediate (ITE) and the delayed (DTE) training effect of orthogonal strength exercises modes and rest intervals in boys aged 8 years.Results. The study results show that in the proposed matrix of the 22 full factorial design, the chosen step of variation of factors is sufficient to study the influence of different modes of strength exercises on the dynamics of ITE in boys aged 8 years. Based on the data analysis, the study obtained regression models of load for calculating the ITE1, ITE2, and DTE. The obtained regression models make it possible to calculate the number of repetitions and rest interval to achieve the most rational load variant.Conclusions. The analysis of regression equations shows the interrelation between training effects: ITE1 —> ITE2 —> DTE. The value of ITE1, ITE2, and DTE at station I (exercises to strengthen arms and shoulders) and station II (exercises to strengthen abdominal muscles) depends on the increase in the number of repetitions in a set and the duration of the rest interval. The value of ITE1, ITE2 at station ??? (exercises to strengthen back muscles) depends on the increase in the number of repetitions in a set and the duration of the rest interval. The value of DTE – on the increase in the number of repetitions in a set and the reduction of the rest interval duration. The value of ITE1 at station IV (exercises to strengthen leg muscles) depends on the increase in the number of repetitions in a set and the reduction of the rest interval duration. To strengthen the DTE, it is necessary to reduce the number of repetitions in a set and the duration of the rest interval.