Intrinsic athlete characteristics as predictors of shoulder injury and throwing performance in water polo

Abstract

The purpose of this thesis was to investigate risk factors for shoulder injury in sub-elite water
polo players. The focus was the relationship between shoulder injury risk, throwing
performance and the intrinsic athlete characteristics routinely measured by clinicians and
coaches, including shoulder strength, range of motion (ROM), and proprioception.
Despite growing interest in injury prevention, few studies have investigated epidemiology and
risk factors for shoulder injury in water polo athletes. Accordingly, the first study in this
thesis includes a systematic evaluation of the water polo literature and shoulder injury risk.
The main findings were that reported shoulder injury rates vary from 24 to 51%, and that risk
factors are likely multifactorial. Practical implications arising include monitoring of
individual athletes’ loading and scapular dyskinesis, and preservation of shoulder strength and
ROM.
The second study investigated the epidemiology of injury in sub-elite water polo players and
impact on ability to train. Shoulder injury was not only the most frequently reported injury,
but was also over-represented in loss of training time, accounting for 16% of total injury and
25% of all loss of training time.
The association between shoulder injury and changes in shoulder strength and ROM has not
been clearly established in water polo athletes. The third prospective study demonstrated a
significant difference, for athletes that experienced a subsequent in-season shoulder injury
compared to those that did not, in pre-season shoulder strength as a percentage of body weight
and athletes’ total ROM. The results support the use of clinical measures of shoulder strength
and ROM pre-season and provide clinical guidelines for targeted intervention.
Shoulder strength is routinely measured by clinicians working with water polo athletes, but
the inter-rater reliability of hand-held dynamometry (HHD) is unknown. The fourth study determined the inter-rater reliability of strength assessment in both a neutral and throwing position (90-90). The 90-90 testing position demonstrated superior reliability with no
systematic bias, unlike the neutral position. These results support the use of HHD assessment
of water polo athletes in the 90-90 position for preseason screening.
Proprioceptive acuity has been attributed to an athlete’s level of sporting attainment. The final
study investigated the relationship between proprioception acuity on-land and in-water and an
athlete’s throwing performance as rated by their coach. To improve ecological validity
relative to previous proprioception testing, an in-water shoulder active movement extent
discrimination apparatus (AMEDA) was developed and built. A significant correlation was
demonstrated between an athlete’s in-water proprioception acuity and coach rated throwing
performance.
Collectively, these findings contribute to the water polo literature body by providing
normative screening data for sub-elite level water polo players. Further, individuals with
reduced shoulder strength or change in ROM below recommended cut off values can be
identified pre-season and appropriately managed. Additionally, recommendations are made
regarding strength testing reliability and positioning. Finally, the adapted in-water AMEDA
has been shown to be a valid measure for the cohort and the findings provide direction for
future research into the role of proprioception, throwing performance and injury risk.

Date of Award	2019
Original language	English
Supervisor	Jeremy WITCHALLS (Supervisor) & Gordon WADDINGTON (Supervisor)