RELIABILITY AND VALIDITY OF THE BOSCO MECHANICAL POWER JUMP TEST:

The Bosco Mechanical Power Jump Test (BT) is a measure of the mechanical power production of the legs during 15 to 60 seconds of maximal vertical jumping. The reliability and validity of the test have been questioned. Purpose: To determine the intersession reliability and validity of the 60 s BT. Methods: Twenty-nine college age subjects (18 M/11 F) completed a timed 40 m sprint, 30 second Wingate Anaerobic Test (WAT), and two trials of the 60 s BT on different days. Testing order was randomized to eliminate any effects of testing order. Forty-meter sprint time was measured to the nearest 0.001 seconds using photoelectric cells. WAT was measured on a pan loaded Monarch cycle ergometer with the workload set at 7.5% of body weight. BT was performed on a switch mat interfaced with a PC that recorded the number of jumps, flight time and time in contact with the mat. Subjects performed as many maximal jumps as possible in 60 s while keeping their hands on their hips and bending their knee to approximately 90 degrees when in contact with the mat. Power was calculated from the total number of jumps in 60 s, flight time and time in contact with the mat. Intersession reliability was estimated for the BT using a one-way random effects intraclass correlation (ICC). Concurrent validity was estimated using the 40 m sprint and the WAT as criterion scores. Results: Mean values for the two trials of the BT were 12.64 ± 3.08 and 12.56 ± 3.55 W/kg respectively. ICC estimate for the 60 s BT between sessions was 0.93. Mean values for the 40 m sprint and WAT were 8.941 ± 1.055 s and 7.66 ± 1.13 W/kg respectively. Correlation coefficients (Pearson r) between the BT and 40 m sprint and WAT were −0.814 and 0.827 respectively (p≤0.0001). Conclusions: These data suggest that the BT is a reliable measure of mechanical power production of the legs. Furthermore, validity estimates of BT suggest it is similar to other measures of mechanical power reported in the literature.