Author(s): BÖHLKE, N., FREITAG, N.1, PEITZ, M.1, HAASE, D.1, LEGERLOTZ, K.2, Institution: OSP BERLIN, Country: GERMANY, Abstract-ID: 1008

INTRODUCTION:
Resistance training is considered safe for children and essential for youth athletes. However, valid tests for assessing strength levels in this population under field conditions remain limited. While the isometric mid-thigh pull or maximum number of pull-ups are promising tools for assessing knee-hip-extension and upper-body pulling strength, valid tests for assessing upper-body pushing strength are lacking. Embedded in a three-stage project, we introduce the upper-body isometric squeeze test (IST) as a novel and efficient field test to close this gap.
METHODS:
In a preceding investigation we established a high criterion validity between IST and bench press (BP) performance in strength training experienced adults (overall r=0.93, n=30; men r=0.88, n=15, 10.5 years strength training experience; women r=0.77, n=15, 9.1 years experience). To assess if this correlation remains stable in a younger cohort, we recruited 44 youth athletes with initial strength training experience (n=24 boys, 15.4±1.4 years old; n=20 girls, 14.4±1.6 years old) from regional performance development programmes in four different sports. Self-reported BP experience was 2.2±1.0 years in the boys and 1.7±0.8 years in the girls. After a standardised warm up, the participants completed a 1-to-5-repetition maximum BP protocol (RMP) and IST in a randomized order during one testing session. IST required a 3-second bilateral compression of a mobile dynamometer (DynaMo Plus, VALD, Brisbane, Australia) in front of the chest while lying in a supine position. BP performance was established using an estimated 1-repetiton-maximum (1RM) derived from the RMP. Criterion validity was assessed using Pearson correlation between BP 1RM and IST peak force.
RESULTS:
Mean BP 1RM was 74.7±18.5kg for the boys and 49.5±15.0kg for the girls, mean IST peak force was 458.0±102.5N and 322.2±69.2N respectively. Criterion validity for the whole cohort was high (r=0,79), for the boys moderate (r=0.64) and higher again for the girls (r=0.74).
CONCLUSION:
These findings indicate that IST can be considered as a valid proxy for maximal upper-body pushing strength. From our previous work we can conclude that general and/or strength-specific training experience might affect the criterion validation, suggesting to explore a more substantial familiarisation than we currently applied. By the same token, we are also still investigating why especially some boys (in contrast to the men in the previous study) struggled with the IST. However, the general ease of use of IST in its current form remains unmatched while still upholding a sufficient validity for a field test. Thus, we plan to investigate in a next step the reliability of IST in even younger youth athletes with limited to no (barbell-based) strength training experience.