THE RESEARCH PLAYBOOK
41.0
Low-usage natural turfgrass field
73 Gmax
35 Gmax
48.3
Field Average:
46.8 Gmax
FIGURE 2
56.3
High-usage natural turfgrass field
70 Gmax
33 Gmax
44.1
Field Average:
49.8 Gmax
RESULTS AND DISCUSSION SURFACE HARDNESS DATA Heatmaps shown in Figure 2 highlight surface hardness variability within each field studied. Both synthetic turf fields had significantly harder surfaces than the natural turfgrass fields( p < 0.001), and for both surface types, the high-usage field had a significantly harder surface than the low-usage field( p = 0.0029 for the natural turfgrass fields and p < 0.001 for the synthetic turf fields). Both synthetic fields tested in this study were not constructed with a shock pad, which is typically placed beneath the layer of material that supports the synthetic fibers and is utilized to help replicate the cushioning effect of natural turfgrass. The absence of a shock pad, along with the tendency of synthetic turf to harden over time due to infill material compaction from athlete foot traffic, may explain the harder surface values observed on the synthetic fields compared to the natural fields. Further, increased use or foot traffic on both natural turfgrass and synthetic turf leads to compaction, which causes the playing surface to harden over time. Therefore, it is anticipated that the high-usage fields exhibited higher surface hardness compared to the low-usage fields.
53.8
Low-usage synthetic turf field
76 Gmax
41 Gmax
67.0
Field Average:
61.3 Gmax
High-usage synthetic turf field
87 Gmax
60 Gmax
70.3
66.2
Field Average:
69.7 Gmax
DATA WITHIN EACH HARD AND SOFT AREA Resulting rotational resistance, thatch depth, soil moisture, and infill depth( synthetic fields only) measurements taken within each hard and soft area on all four fields are presented in Table 1. These measurements( n = 20 per both hard and soft areas within each field) were analyzed using analysis of variance, and means were separated using Fisher’ s protected least significant difference( LSD) test at = 0.05 to evaluate statistical differences between locations.
STATSPORTS GPS UNIT DATA GPS units were securely attached to each athlete’ s upper back, as shown in Table 2. These devices were used to determine if athlete running speed varied based on field type, field usage level, or hardness. However, no statistically significant differences were found. This consistency in speed across conditions is important because running speed can directly affect impact forces and biomechanical measurements. Prior studies have shown that faster running increases
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