The effects of fatigue on consecutive unilateral and bilateral jump task execution

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Bellemare, Alixandra
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PROBLEM: Lower limb injury rates are on the rise in conjunction with increased leisure activity participation. These injuries can occur due to contact, or due to an individual’s movement. Injury risk screening has become more prevalent due to this rise in injury rates, but there is no general consensus in the current literature about how an individual’s movement will change when performing multiple jumps or landing tasks, as well as when in a fatigued state. This is important as these tests may better correlate with real-life task execution in practice and competition. PURPOSE: To assess the biomechanics of individuals performing bilateral and unilateral consecutive jump tasks pre- and post-fatigue, and to determine if there are any changes to these movements. METHODS: A protocol consisting of consecutive bilateral counter movement jumps (CMJ) and consecutive forward moving single foot jumps (FMSFJ) was assessed pre- and post-fatigue in a healthy athletic population. RESULTS: Main effects of jump type and fatigue were found in 13 and 8 of the 16 variables, respectively. Participants landed in a less flexed position at the trunk, hip, knee, and ankle in the FMSFJ compared to the CMJ, as well as less flexed in both jump protocols post-fatigue, at initial contact and peak flexion. Participants also showed more hip and knee abduction at peak landing in the CMJ protocol, and in pre-fatigue conditions. CONCLUSIONS: Comparing the CMJ and FMSFJ protocols, data suggest the landings produced in the CMJ are less risky, as these jumps are performed with larger peak joint angles in the sagittal plane. However, due to potential greater risk with the FMSFJ, this jump protocol may be better for assessing future injury risk in an athletic population, while the CMJ protocol may be better for assessing participant sensitivity to fatigue.
Injury, Injury prevention, Lower limb, Movement assessment