PEAK TORQUE AND ROTATIONAL STIFFNESS OF BERMUDAGRASS, PERENNIAL RYEGRASS, KENTUCKY BLUEGRASS AND TALL FESCUE

摘要

Epidemiological research in Australian football concluded there was a lower risk of Anterior Cruciate Ligament (ACL) injury on perennial ryegrass (Lolium perenne L.) compared to bermudagrass (Cynodon dactylon (L.) Pers.and its hybrids with C.transvaalensis Burtt Davy).Bermudagrass was perceived as having high rotational traction and a tendency to trap players’ boots and place more stress on knee ligaments.The objective of this study was to generate comparative data on the peak torque and rotational stiffness of hybrid bermudagrass,perennial ryegrass,tall fescue (Festuca arundinacea Shreb.) and Kentucky bluegrass (Poa pratensis L.) to assist ground managers in the selection of appropriate species.Eight assessments were conducted over twelve months on replicated plots controlled for age,thatch depth,hardness,soil type and soil moisture.The mean peak torque of hybrid bermudagrass was significantly higher than perennial ryegrass on four out of eight assessment dates and significantly higher than tall fescue on five assessment dates and Kentucky bluegrass on two assessment dates.Over the full year,however,there was no significant difference in mean peak torque between tall fescue (58 Newton-metres),perennial ryegrass (60 Nm),Kentucky bluegrass (65 Nm) and hybrid bermudagrass (67 Nm).However,perennial ryegrass had significantly higher rotational stiffness than hybrid bermudagrass on four assessment dates,than tall fescue on five assessment dates and compared to Kentucky bluegrass on two assessment dates.Over the full year,mean rotational stiffness of perennial ryegrass (6.8 Nm/deg) was significantly higher than hybrid bermudagrass (5.8 Nm/deg) and tall fescue (5.7 Nm/deg) but not significantly different to Kentucky bluegrass (6.6 Nm/deg).Rotational stiffness is arguably more relevant to ACL injury risk than peak torque and the overall conclusion is that there is no reason to favour perennial ryegrass and to recommend against the use of hybrid bermudagrass for football fields for reasons concerning ACL injury risk.