  This study aimed to assess the reliability and validity of the Polar V800 to
measure vertical jump height. Twenty-two physically active healthy men (age:
22.89 +- 4.23 years; body mass: 70.74 +- 8.04 kg; height: 1.74 +- 0.76 m) were
recruited for the study. The reliability was evaluated by comparing
measurements acquired by the Polar V800 in two identical testing sessions one
week apart. Validity was assessed by comparing measurements simultaneously
obtained using a force platform (gold standard), high-speed camera and the
Polar V800 during squat jump (SJ) and countermovement jump (CMJ) tests. In the
test-retest reliability, high intraclass correlation coefficients (ICCs) were
observed (mean: 0.90, SJ and CMJ) in the Polar V800. There was no significant
systematic bias +- random errors (p > 0.05) between test-retest. Low
coefficients of variation (<5%) were detected in both jumps in the Polar V800.
In the validity assessment, similar jump height was detected among devices (p >
0.05). There was almost perfect agreement between the Polar V800 compared to a
force platform for the SJ and CMJ tests (Mean ICCs = 0.95; no systematic bias
+- random errors in SJ mean: -0.38 +- 2.10 cm, p > 0.05). Mean ICC between the
Polar V800 versus high-speed camera was 0.91 for the SJ and CMJ tests, however,
a significant systematic bias +- random error (0.97 +- 2.60 cm; p = 0.01) was
detected in CMJ test. The Polar V800 offers valid, compared to force platform,
and reliable information about vertical jump height performance in physically
active healthy young men.
