Dwell Time of Shinguards over One Season in College, High School, and Youth Female Soccer Players

Abstract

Many studies have been performed on the ability and effectiveness of shinguards to dissipate force. These studies have shown that shinguards can reduce force thus reduce injury; however, none have evaluated how long shinguards are effective. The purpose of this study was to determine if the amount of usage that a shinguard gets over time is detrimental to its ability to dissipate force. There were 36 participants recruited for this study from three different female soccer teams; Division I, high school, and a youth team. Twenty seven participants completed the study. Subjects were divided into 14 participants in the older age group, high school and college, and 13 participants in the younger age group the youth team. Each participant received a pair of Adidas Adi shinguards (ADIDAS, Spartanburg, SC). Baseline tests of all shinguards occurred before handing them out to the participants. Shinguards were collected from the teams on four occasions: ¼, ½, ¾ of the way through the season, and after post-season. Fifteen pairs of control shinguards were not used by the participants but tested on each occasion. A drop track consisting of a 5kg weight was used to test the shinguards. The weight was dropped from a height of 40cm. An accelerometer (Biopac Systems, Inc, Tri-Axial SS26-2, Goleta, CA) was attached to record data. The shinguards were strapped to a wooden model leg. The 5kg weight was raised and dropped onto the center of each shinguard five times on five separate occasions for a total of 25 hits. Dwell time, the amount of time the weight is in contact with the shinguard during each impact in milliseconds (ms), was calculated for each trial. A repeated measure ANOVA was used to identify any changes over time. A priori alpha level was set at p<0.05. The primary finding in this study was that dwell time did not significantly change through the course of one season. The RMANOVA revealed no significant difference between testing sessions, (F4,244 = 2.15, p = 0.08), between groups (F2,61 = 0.34, p = 0.72), and no time by group interaction (F8,244 =0.56, p = 0.81). Based on these findings, we can conclude that shinguards do not degrade, as measured by dwell time, over one season. It is best to follow manufacturers guidelines and purchase shinguards when the old ones are broken, deformed, or missing any pieces.Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Sciences in the Department of Kinesiology of, Indiana University May 201