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Ratio of forces (RF) were investigated during early acceleration by analysing block and standing starts in trained sprinters. RF variables over the initial block exit/push-off and the first four steps were determined from force plate data, and a simple macroscopic model was also applied to obtain RF variables from the velocity time-history over the entire acceleration phase. Large positive correlations existed between mean early acceleration RF and early acceleration performance from both standing (r = 0.82) and block (r = 0.89) starts, and both theoretical maximal RF and the rate of decline in RF combined to be important predictors (adj. R2 = 92-97%) of performance. From the simple macroscopic model, maximum RF was nearly perfectly correlated with early acceleration performance (r = 0.96) and thus appears to be an excellent simple measure for early acceleration.