MAXIMUM MUSCULAR POWER
• Boxes of varying heights—for example, 20 cm
(7.9 inches), 30 cm (11.8 inches), and 40 cm (15.7
• A commercial device able to measure contact
time—for example, a jump or contact mat (contact
mat systems calculate jump height using
flight time (37, 62, 122)
• One tester/recorder
1. Begin with the athlete standing on top of the
drop box with the contact mat placed at least
0.2 m in front of the box.
2. Instruct the athlete to place hands on hips,
to step forward off the box without stepping
down or jumping up, and, upon contact with
the ground, to jump as high as possible while
minimizing contact time as much as possible
3. The takeoff and landing positions, as well as
jumping strategy, should be the same for each
4. From the measuring device, obtain the jump
height and contact times.
5. The best of three trials is recorded.
6. Calculate the reactive strength index as jump
height divided by contact time.
7. The procedure can be repeated from boxes of
varying heights to obtain a stretch tolerance
profile for the athlete.