Muscle stiffness in females : measurement considerations and relationship with physical performance and injury risk in netball

University of Technology Sydney. Faculty of Health.NO FULL TEXT AVAILABLE. This thesis contains 3rd party copyright material. The hardcopy may be available for consultation at the UTS Library.NO FULL TEXT AVAILABLE. This thesis contains 3rd party copyright material. ----- Stiffness is a mechanical property of human muscle that has been widely researched however, few studies have conducted research using female participants. Previously, stiffness has been related to performance variables and injury incidence in male and mixed-gender cohorts. Since stiffness levels differ significantly between the genders, it is important to explore the stiffness-performance and stiffness-injury relationships with all-female cohorts. Results from such studies will be particularly relevant to female dominant sports such as netball. Despite a high rate of participation in Australia and other Commonwealth countries, there is a distinct lack of research pertaining to factors relating to performance and injury in netball. To address these issues, four separate studies were undertaken. Study one determined the validity and reliability of three methods of stiffness assessment in females. The results indicated that myometry and the vertical hop test provided valid and reliable measures of stiffness in females. Study two compared the active and passive stiffness of females competing at four distinct levels of netball competition. The outcomes suggested that elite players possess higher levels of active stiffness when compared to lower-ranked counterparts. Study three compared the stiffness of female netballers to a number of performance variables associated with netball and other court/team sports. The results from study three revealed a number of relationships suggesting that higher levels of lower-body stiffness are advantageous for female athletes when performing rapid and/or repeated stretch-shorten cycle movements. Particularly strong relationships between the stiffness of the medial gastrocnemius and rapid stretch-shorten cycle movements were revealed, suggesting that the medial gastrocnemius is of particular importance when considering performance. Finally, study four examined the relationship between lower-body stiffness and injury incidence in netballers. The results suggested that elite and sub-elite netballers have a higher rate of injury incidence than recreational athletes. Specifically, relatively high stiffness of the soleus and Achilles tendon appears to be related to lower-body injury incidence in females, particularly at the elite level. The results from the four studies discussed in this thesis are relevant for female athletes, their coaches, conditioning staff, medical personnel and talent identification and development programs. Whilst these studies involved netballers, the results are also applicable to other team sport athletes, especially those playing court sports such as volleyball, basketball and European handball, which involve similar performance characteristics to netball