Wet-bulb Globe Temperature Indices for Different Tennis Court Surfaces

Tennis is played on various court surfaces, which can be broadly classified into hard courts, sand-filled artificial grass courts, and clay courts, as the most common surfaces in Japan. In a high heat environment, players are exposed to heat load from the sun, solar radiation, and radiation from the ground surface. These effects are expected to vary depending on the court surface material. PURPOSE: This study aimed to evaluate the thermal environments of different tennis court surfaces using wet-bulb globe temperature (WBGT) meters. METHODS: Portable WBGT meters were installed at an outdoor hard court, a sand-filled artificial grass court, and a clay court (a softball field) in a university campus. The WBGT was recorded hourly from 9:00 to 17:00 from June 1, 2022, to September 21, 2022. The data were compared with the WBGT data of the nearest observatory published by the Ministry of the Environment (MOE) for each level of the heat stroke prevention exercise guidelines regulated by the Japan Sports Association. RESULTS: The median WBGTs on each surface were significantly higher (p < 0.01) for hard courts at the “Warning” level or above, for sand-filled artificial grass courts at the "Severe Warning" level or above, and for clay courts at the “Danger" level than the MOE WBGT (Fig. 1). No significant differences were observed between court surfaces. CONCLUSION: Compared with the data published by the MOE, hard courts and sand-filled artificial grass courts are played under particularly severe heat conditions, suggesting that proactive measures against heat are required, such as measuring WBGT and providing cooling measures.