Validity and Reliability

1) Arteaga, R. Dorado, C. Chavarren, J. Calbet, J.A.L. Reliability of jumping performance in active men and women under different stretch loading conditions. Journal of sports medicine and physical fitness 40(1), Mar 2000, 26-34
To determine the reliability of squatting jumps (SJ), counter-movement jumps (CMJ) and drop jumps (DJ) tests, as well as the reliability of the optimal dropping height during drop jumping. Jumping performance was assessed in 8 male and 9 female physical education students. Their age, weight and height (mean +/- SD) were 23.9 +/- 2.1 years, 72.0 +/- 12.1 kg, 174.3 +/- 10.4 cm, and 23.1 +/- 2.0 years, 54.8 +/- 4.9 kg, 160.1 +/- 5.0 cm for the males and females, respectively. The jumping performance was determined on six different testing days. On each testing day, squatting jumps (SJ) and counter-movement jumps (CMJ) were performed as well as drop jumps (DJ) from heights between 20 and 100 cm. The dropping height given the maximum attained height was registered as the optimal dropping height (ODH). After a 15 min rest period, a 30 sec hopping test (HT) was performed and the mean height attained (MHT) as well as the number of jumps executed (NHT) were recorded. The height attained was computed from the flight time, which was measured with a digital timer (+/- 0.001 sec) connected to a resistive platform. The pooled coefficients of variation in percentage were 5.4 (SJ), 6.3 (CMJ), 6.2 (DJ), 31.9 (ODH), 3.1 (NHT) and 6.7 (MHT). A parabolic relationship between dropping height and attained height was found (r = 0.39-0.43, p < 0.001). The ODH was 48.2 +/- 14.0 cm and 62.9 +/- 21.3 cm for females and males, respectively (p < 0.05). Multiple regression analysis showed than ODH can be predicted from the SJ with a standard error of 9 cm. The variability of the assessment of jumping performance is similar to that reported for other variables used in the assessment of physical fitness. In contrast, the assessment of the optimal dropping height is less reliable.


Kellis, S.E. Tsitskaris, G.K. Nikopoulou, M.D. Mousikou, K.C. The evaluation of jumping ability of male and female basketball players according to their chronological age and major leagues.Journal of strength and conditioning research 13(1), Feb 1999, 40-46 
The purpose of our research was to evaluate and compare the jumping ability among male and female basketball players according to their chronological age and major league. The sample consisted of 379 basketball players, 214 men and 165 women, ranging from 13 to 30 years old. For the evaluation, an electronic contact mat was used. A series of five vertical jumps were performed: squat jump (SJ), counter-movement jump (CMJ), drop jump (DJ), and rebound jumps for 15 seconds (RJ15s) and 30 seconds (RJ30s). A oneway analysis of variance was used for the comparison of the height of the jumps among sexes and major leagues. The results, as was expected, revealed statistically significant differences in the height of the jumps between the two sexes at all ages. The only exception was the SJ at the age of 13 (P = 0.12). Regarding the male, major statistical differences were revealed between ages with respect to the older ages. It is remarkable that the ages, two by two consecutively, did not present statistically important differences in any of the jumps. Generally, an increasing tendency was observed in the height of the jumps in relation to chronological age. As far as the male leagues are concerned, statistical differences were observed between league C’ and A2′ or B’, especially in RJ30s, and between A2′ and B’, especially in SJ and CMJ with respect to the first ones mentioned (C’ in RJ30s and A2′ in SJ and CMJ). Regarding the females, less statistically significant differences were observed among ages. An unsimilar course appeared with a declining tendency of the height of the jumps, especially at the age of 16. On the contrary, as far as females’ competitive leagues are concerned, no statistically significant differences were revealed in any of the jumps.