Effects of Relative Drop Heights of Drop Jump Biomechanics in Male Volleyball Players

Abstract

Previous cross-sectional studies have reported that higher drop heights do not always result in improved performance, and may increase injury risk during drop jumps (DJ). The purpose of this study was to analyze the kinematics and kinetics during the DJ in order to determine the relative drop height that maximize performance without exposing the lower extremity joints to unnecessary loads. Twenty male Division I college volleyball players volunteered. Data were collected using 11 infrared cameras and two force platforms. Participants performed three maximal effort countermovement jumps (CMJ). Subsequently, 50, 75, 100, 125, and 150% CMJ height (CMJH) was used to scale their relative drop height for three DJ trials per height. There was a significant increase in the landing phase impulse when the drop height exceeded 100%CMJH (p<0.05). At 125% and 150%CMJH, the negative work of knee and ankle significantly increased. The incoming velocity, kinetic energy, landing depth, maximum ground reaction force, landing impulse and power absorption of knee and ankle all increased with drop height (p<0.05). DJ height and reactive strength index following the drop landing were not statistically different between any of the drop heights (p>0.05). 50% to 100%CMJH may be the appropriate individual relative drop height for the DJ.

Children’s Single-Leg Landing Movement Capability Analysis According to the Type of Sport Practiced

“…Volleyball players showed lower vertical GRF than the gymnastic and control groups, regardless of body weight. This supports previous findings which concluded that volleyball players seem to be able to absorb an impact force between 1.9 to 4.0 times their body weight [ 31 , 39 , 40 ]. These results might be related to lower limb movement, wherein a negative correlation between knee flexion and the magnitude of the peak GRF is found [ 41 , 42 ].…”

“…This could be also due to the nature of volleyball wherein, rather than gymnastics during landing, volleyball players must control their GRF quickly in order to react to any other unexpected stimuli incoming from the game [ 43 ]. Even though a study in volleyball suggested that impact force attenuation depended on the height of the drop [ 39 ], these results indicate that volleyball players have fewer lower limb injuries because the game seems to be associated with strategies of impact force attenuation.…”

The Acute Effect of Foam Rolling and Vibration Foam Rolling on Drop Jump Performance

“…The DJH time × protocol interaction was significant (p = 0.022; η 2 = 0.171; statistical power = 0.781). Simple main effects showed significant improvements in DJH after FRE at POST2 when compared with The formula: 1 8 gT 2 (g = 9.81 m/s −2 ; T = t 4 − t 3 ) was used to calculate drop jump height (DJH) [25,26]. The mechanical power of the hip, knee, and ankle joints was calculated by inverse dynamics and normalized by body weight.…”

“…The instant of the first and second foot contact (t1 and t4) and take-off of the foot from the force platforms (t3) was determined by assessing the 30 Newton vertical ground reaction force threshold. The formula: gT 2 (g = 9.81 m/s -2 ; T = t4 − t3) was used to calculate drop jump height (DJH) [25,26]. The mechanical power of the hip, knee, and ankle joints was calculated by inverse dynamics and normalized by body weight.…”

“…The mechanical power of the hip, knee, and ankle joints was calculated by inverse dynamics and normalized by body weight. The joint power generated by the joint muscle and tendon was defined as positive mechanical power [26]. The joint power was averaged in the take-off subphase.…”