More Accessible Methods for Measuring Contact Time and Vertical Jump Height: DROP JUMP

Abstract

Objective: The objective was to analyze more accessible, cheap and valid methods for quantifying the height and contact time (CT) of the vertical drop jump (DJs).

Methods: The research consisted of 2 groups, 17 high-performance athletes (G1), (age: 21.8 ± 2.6 years) and 16 beginner sports athletes (G2), (age: 13.5 ± 2.2 years). Three DJ jumps were performed with 30” intervals between them on the contact platform (CP), simultaneously recorded with an iPhone 8 in the frontal plane, where the CT and jump height were measured in the My Jump 2 app (MJ2) and with a Samsung smartphone in the lateral plane to quantify the CT and flight time in the kinovea software (SK) (by two different evaluators), to later quantify the jump height. For data analysis, only the highest jump was used, quantified by CP. The intercalary correlation coefficient (ICC), Person correlation (r) and Bland- Altman graphs were used to test the reliability, correlation and agreement of the methods tested with the TAP.

Results: Correlations and reliabilities for jump height in G1 and G2 were almost perfect (r=1; ICC=1; CI=1-1; p<0.001). CT in groups G1 (r=698-963; ICC=677- 964) and G2 (r=485-995; ICC=273-993) varied.

Conclusion: The MJ2 and SK are reliable for measuring jump height and TC during the drop jump.