Abstract:
A warm-up is an important period before training or competition to prepare an athlete for
the physical demands of subsequent activity. An ongoing debate exists in the current literature
as to whether static stretching should be included in a warm-up practice to reduce injury risk
during sport. Prior research has extensively focused on the effects of static and dynamic warmups in relation to jumping performance, however, limited research has examined the
biomechanical nature of landings following these warm-up practices. Compared to males,
female athletes display landing mechanics that may increase the risk of lower extremity injury.
The sport of women’s volleyball require athletes to perform many unilateral landing tasks that,
compared to bilateral maneuvers, further enhance injury risk. In the present study, twelve
female, collegiate-level volleyball players performed unilateral landings on the dominant and
non-dominant limb both pre- and post-dynamic (DWU) and combined dynamic-static (CDS)
warm-ups. Kinetic and kinematic variables of interest were measured at the hip and knee during
the landing phase of a volleyball-simulated jump-landing maneuver. A significant three-way
interaction (warm-up x limb x time) was observed for peak internal knee adduction moment and
peak hip adduction angle. Non-dominant knee adduction moment increased (p = 0.013; d =
0.79) 1 minute post CDS warm-up, while hip adduction angle in the non-dominant limb
decreased (p = 0.016; d = 0.38) 15 minutes post CDS warm-up. No other warm-up differences
were detected, however, significant main effects of limb were determined, as the non-dominant
limb demonstrated an increase in peak knee external rotation moment, internal rotation angle,
and knee abduction angle. The landing patterns in the non-dominant limb may be due to altered
hip and trunk mechanics during the jump-landings, potentially placing the non-dominant limb at
a higher injury risk. Main effects of time were also revealed for peak knee internal rotation
moment, knee abduction angle, and knee external rotation / internal rotation, potentially
attributed to the frequency of jump-landings performed in this analysis. Static stretching
following a DWU may acutely place a female volleyball player at a higher risk for a non-contact
knee injury in the non-dominant limb, therefore it is recommended that athletes be allowed a rest
period prior to training or competition if static exercises are included in pre-activity practices.
Additional consideration must be given to limb dominance in this population, as training should
incorporate single-leg landing technique and muscular strengthening exercises to reduce injury
risk from repeated unilateral landings. The results of this analysis may provide practitioners with
biomechanical information to determine warm-up protocols and training methods that adequately
prepare a female volleyball athlete for sport demands.