The objective of the present study was to determine the effect of interval session running at high intensity with 1% or 10% gradient on the height of the drop jump. The cinematic variables concentric phase, eccentric and contact time were compared after the running session in both conditions in order to explain possible changes in the jump performance. The investigators theorize that the lower eccentric overload in the running to 10% inclination promotes higher deleterious effect on power performance of the lower limbs

Physical training programs are typically composed of activities directed to the development of different valences usually stimulated in the same session. When aerobic activities of long duration prior isokinetic strength exercises, isotonic, or explosive, deleterious effects seem to be induced on performance of these valences. These short and long-term changes in muscle strength and power would be directly associated with repetitive eccentric loads that characterize the endurance running. Gradual increases in the running slope were inversely associated with a proportional reduction in the eccentric loads, which in turn would result in less muscle damage to intra and extrafusal fibers. So, the change in the slope of the race would emerge as an optional way to neutralize the competitive effect on the power performance. The research consisted of five visits. At the initial visit was conducted familiarization to vertical drop jump, and immediately after, the determination of VO2max values and their associated speed (vVO2max). The second visit was a new familiarization for the vertical drop jump followed immediately determining the Time to exhaustion performance in vVO2max (100% of VO2Max). Two jumps were performed on each of the three selected heights (20, 30 and 40 cm) were used in the experimental sessions and control only the height associated with the highest performance. In subsequent visits (third to fifth), participants performed three maximum jumps before and about 10 min after the following conditions: high intensity Interval running a 10% gradient (C10%), 1% grade (C1%) and control condition (CON).

Inclusion Criteria:

• age: 18 at 45 years
• no cardiovascular or metabolic problems
• minimum level of aerobic activity recommended by American College of Sports Medicine

Exclusion Criteria:

• no joint or muscle injuries
• no use ergogenic or anabolic resources