Lumbopelvic instability: A key in injury risk among pre-elite youth athletes?

Background
Sporting injuries can result in substantial financial and physical detriments to an athlete, including pain, loss of game and/or training time, costly rehabilitation and/or medical attention, and even cause long-term disability. To reduce these substantial injury rates, many sporting teams have adopted movement screening tools for injury risk management purposes. This early identification of athletes with “poor” movement competency, can then allow intervention strategies to be implemented, potentially preventing the injury from occurring and thus reducing the injury rate seen among the sporting population. Implementation of neuromuscular training interventions programs in athletes at increased risk of sporting injuries have been widely utilised. However, the current local focus on injury prevention at specific joints, when compared to a focus on the global kinetic chain, is less effective, as evidenced by high rates of re-injury. Research suggests that lumbopelvic stability may be critical in the prevention of lower limb injuries in athletes; however, it is unknown how much of an effect lumbopelvic instability has on lower limb injury risk.
Thesis Aim
The first purpose of this thesis was to determine the inter- and intra-rater reliability of a field-based movement screen in novice and expert raters using different viewing methods, and evaluate the presence of a familiarisation effect (Manuscript 1). A second aim of this thesis was to determine the effect of different 12-week intervention programs to modify a stop-jump (Manuscript 2) and reactive change-of-direction (R-COD) (Manuscript 3) in pre-elite youth athletes. A third aim of this thesis was to determine the effect, if any, trunk abdominal segment relative to the pelvis segment (trunkab-pelvis) range of motion had on lower limb injury risk factors (Manuscript 4).
Methods
For Manuscript 1, 55 pre-elite youth athletes performed a movement screen on three separate occasions and videos of their performance were rated three times in randomised order by 18 raters. Reliability was established using inter- and intra-rater reliability of novice and expert raters, with learning effects and familiarisation measured across repeated exposure of both raters and athletes, respectively. Within Manuscript 2 to 4, eighty-nine junior pre-elite athletes with no current signs or symptoms of injury were recruited from the Western Region Academy of Sport. Biomechanical analysis of five successful stop-jump and five R-COD experimental tasks were completed both before and after exposure to one of three different 12-week training programs, or the control program, in conjunction with a strength and conditioning program for each participant. Mixed effect repeated measures analysis of variance (ANOVA) was used to determine statistically significant between-group differences (P≤0.05).
Major Conclusions
Results of this study indicate that movement screening experience does not affect rater reliability; however, familiarisation is required for athletes performing the movement screening. Total movement screening score can be reliably used to determine movement competency; however, individual movements scores should not be relied on. When implementing strength and conditioning programs in pre-elite youth athletes to modify jump-landing technique, a simple strength and conditioning program comprising of four exercises with limited equipment required, can be implemented in pre-elite youth athletes with poor movement competency to modify their landing patterns. As a result of these interventions, athletes displayed a more upright trunkab-pelvis segment at landing that was not shown to alter the risk of lower limb injury; however, it is unknown whether this movement strategy is beneficial or detrimental to athletic performance. This current study failed to identify links between trunkab-pelvis ROM, injury risk and/or performance. It is suggested that further research is needed to determine how trunk ROM during landing tasks affects these factors influence lower limb injury risk and athletic performance.