title: The type of mat (Contact vs. Photocell) affects vertical jump height estimated from flight time.
abstract: The purposes of this study were to analyze the validity and reliability of 2 photocell mats and to probe the possible influence of the type of mat (contact vs. photocell) on vertical jump height estimated from flight time. In 2 separate studies, 89 and 92 physical students performed 3 countermovement jumps that were simultaneously registered by a Force Plate (gold standard method), 2 photocell mats (SportJump System Pro and ErgoJump Plus), and a contact mat (SportJump-v1.0). The first study showed that the 2 photocell mats underestimated the vertical jump height (1.3 ± 0.2 cm and 5.9 ± 5.2 cm, respectively), but only SportJump System Pro showed a high correlation with the Force Plate (r = 0.999 and 0.676, respectively) and good intraday reliability (coefficient of variation = 2.98 and 15.94%, intraclass correlation coefficients = 0.95-0.97 and 0.45-0.57, respectively). The second study demonstrated a strong correlation (r = 0.994) between the 2 technologies (contact vs. photocell mats) with differences in vertical jump height of 2.0 ± 0.8 cm (95% confidence interval = 1.9-2.1 cm), which depended on both flight time and subjects' body mass. In conclusion, SportJump System Pro was a valid and reliable device. The new devices to measure vertical jump height from flight time should be validated. The type of mat (contact vs. photocell) affected approximately 6% the vertical jump height (approximately 2 cm in this study), which should be considered in further studies. The use of validated photocell mats instead of the contact mats was recommended.
authors: Department of Physical Education and Sports, Institute of Biomedicine (IBIOMED), University of León, León, Spain. juan.garcia@unileon.es
authors: Juan
authors: J
authors: García-López
authors: Juan C
authors: JC
authors: Morante
authors: Ana
authors: A
authors: Ogueta-Alday
authors: Jose A
authors: JA
authors: Rodríguez-Marroyo
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D016001:Confidence Intervals; D005080:Exercise Test / Q000295:instrumentation*; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement; D015203:Reproducibility of Results; D013647:Task Performance and Analysis; D013997:Time Factors; D055815:Young Adult