Author(s): FREITAG, N., PEITZ, M., EKIZOS, A., SCHUMANN, M., LEGERLOTZ, K., BOEHLKE, N., Institution: OLYMPIC TRAINING CENTRE BERLIN, Country: GERMANY, Abstract-ID: 525

INTRODUCTION:
Strength testing provides insights into muscular capabilities, performance potential and areas of injury risk and has therefore been a fundamental component of academic research and applied sport science. Two widely employed methods for assessing strength are isokinetic tests and isometric tests. Isokinetic tests measure forces through a predetermined range of motion at a constant velocity, mainly using single-joint movements and performed with specialized equipment. Isometric tests evaluate force generation while maintaining a fixed joint position. A typical example of a whole-body, multi-joint isometric test is the isometric mid-thigh pull (IMTP) test. The aim of this study was to compare the multi-joint IMTP measurements with data collected from mainly single-joint isokinetic tests.
METHODS:
Eighty-five elite level athletes (age 19.9 ± 4.3 years; 30 females) from different sports (canoe, judo, handball, olympic weightlifting, water polo and volleyball) performed IsoK for leg press (100 mm/s, 700 mm/s), knee flexion and extension, trunk flexion and extension (60°/s) as well as the IMTP. After a standardized warm-up the athletes performed the isokinetic strength tests before the IMTP.
RESULTS:
Strong, statistically significant correlations between IMTP and isokinetic tests were found for leg press (r = 0.746 - 0.811; p < 0.01), knee flexion (r = 0.831-0.847, p < 0.01), knee extension (r = 0.846 - 0.864, p < 0.01), trunk flexion (r = 0.739, p < 0.01) and trunk extension (r = 0.733, p < 0.01). The relationships remained significant when subjects were divided by sex for leg press (females: r = 0.616 - 0.732, p < 0.01; males: r = 0.454 - 0.608, p < 0.01), knee flexion (females: r = 0.438 - 0.443, p < 0.05; males: r = 0.655 - 0.696, p < 0.01), knee extension (females: r = 0.663 - 0.665, p < 0.01; males: r = 0.652 - 0.681, p < 0.01) and trunk extension (females: r = 0.478, p < 0.01; males: r = 0.406, p < 0.01). Trunk flexion showed a weak but still statistically significant correlation only for males (r = 0.419, p < 0.01; females: r = 0.162, p > 0.05).
CONCLUSION:
While isokinetic strength tests provide rich data, their lab-based nature prohibits frequent diagnostic events. In contrast, the mobile IMTP can be carried out quickly both in lab and field settings, allowing for more frequent testing, but only providing somewhat gross performance insights. The strong correlations we have shown between the two approaches provide a rationale for implementing the IMTP in the current strength diagnostic routines within the elite sports setting. This is not with the aim of replacing one with the other, but rather to consider them as two elements in a diagnostic chain - from the laboratory to the field.