THE RESEARCH PLAYBOOK asymptomatic areas to decrease . However , winterkilled areas did impact surface hardness ( p = < 0.0001 *). Winterkill creates a substantially harder surface than asymptomatic turfgrass , as the average value for winterkill areas was over 100 Gmax ( Figure 1 ). This presents a concern regarding athlete safety , as the risk of concussion is increased if an athlete were to fall on a winterkill area during competition . Additionally , the risk of other acute injuries , such as stress fractures , and overuse injuries such as shin splints is increased when constantly running on a hard surface .
Figure 1 : Bar graph showing average Clegg results for asymptomatic turfgrass versus winterkill . Letters in bars are to show significant differences .
Figure 2 : Bar graph showing differences in average ball bounce height between asymptomatic turfgrass and spring dead spot ( SDS ).
ROTATIONAL SHEAR STRENGTH Results suggest that spring dead spot patches and winterkill areas both have significantly lower rotational shear strength than asymptomatic turfgrass . Before irrigation , spring dead spot patches had an average shear strength of 415 inches-pounds , while asymptomatic areas had an average shear strength of 497.4 inches-pounds ( p = 0.0001 *). After irrigation , spring dead spot patches had an average shear strength of 420.4 inches-pounds , while asymptomatic areas had an average shear strength of 457.5 inches-pounds ( p = < 0.0001 *). Thus , irrigation caused the rotational resistance of asymptomatic areas to decline significantly when compared to non-irrigated asymptomatic areas ( p = 0.0004 *). For winterkill areas , the average shear strength was 426.6 inches-pounds , while asymptomatic areas had an average shear strength of 518.6 inches-pounds ( p = 0.0001 *). This presents a concern for athlete safety , as athletes have less traction and are more likely to slip if planting their foot in a spring dead spot patch or an area with winterkill .
BALL REBOUND Both spring dead spot patches and areas with winterkill had a significantly higher ball bounce than asymptomatic turfgrass as shown in figures 2 and 3 ( p = < 0.0001 *). Additionally , significant differences were found in ball bounce height between asymptomatic turf and spring dead spot patches for both irrigated and non-irrigated areas ( p =< 0.0001 *). Symptomatic turfgrass lacks a lush turfgrass canopy to cushion the impact of the ball , which may have led to this result . Speaking from experience , misjudging the ball trajectory after bouncing from the turfgrass surface during play negatively impacts an athlete ’ s performance .
Figure 3 : Bar graph showing differences in average ball bounce height between asymptomatic turfgrass and winterkill . Letters in bars are to show significant differences .
RESULTS FROM FLEX TESTING DEVICE Surface stability ( displacement ) and recoil ( rebound ) on the ankle were significantly impacted by spring dead spot ( p <. 0001 ). Non-irrigated spring dead spot patches had an
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32 SportsField Management | August 2024 sportsfieldmanagementonline . com