Abstract

Does there really exist a general vertical take-off power measurable by the jumping height of the ABALAKOW (AB) and the JUMP & REACH (J&R) test? In case of existence both tests should yield 1. approximately equal results 2. with strong intercorrelations. Methods: Sports students without activities like vertical jumps (Stud) and volleyball players with different levels of performance (VB I = low league, VB II = high league) were classified into 2 male and 3 female groups. All athletes had to carry out 3 jumps in both tests: the AB (HOSTER, 1972) and the J&R test (FETZ u. KORNEXL,1993). Only the best out of 3 trials, respectively, was considered in further calculations. Results: Table 1 obviously demonstrates essential differences in the means of the AB and the J&R test concerning 1. the direct comparison of AB and J&R, 2. the comparison of sex, and 3. the comparison of degree of jumping activities. In each case the level of significance amounted at least to 0,01. The rz values exceed in only 1 of 5 cases 53 %. Discussion: The results presented disprove the misconception of a general or unique take-off power. Systematic differences in the mean heights of both tests suggest that whenever vertical take-off power is determined by jumping height, other important variables like technical or motor abilities are involved. Furthermore, tactical and motivational components underline the complexity of the quantity "jumping height". Conclusion: Forces are to be measured in Newton, not in cm. The general take-off power is an abstract construct like a fata morgana, which can only be estimated by motor tests with essential tranfer losses by transforming cm into N. The most intercurrent factor is the coordinative motor component of both tests. Verf.-Referat