Sand vs grass
The aim of this study was to investigate the effect of five-week plyometric training (PT) using different surfaces (sand vs. grass) on sprint and jump performance in young soccer players of the under-20 category. Nineteen soccer players from a professional club in São Paulo (19.3 ± 1.1 years, 1.78 ± 0.06 m; 71.1 ± 6.84 kg) participated in the study. The subjects were divided into 2 groups that performed PT on sand (n=10) or grass (n=9) for five weeks. The results indicated an improvement in performance, as measured by the squat jump (Sand: 18.2%; Grass: 17.6%), countermovement jump (Sand: 12.5%; Grass: 12.4%), drop jump from 44cm (Sand: 8.3%; Grass: 5.8%), drop jump from 66 cm (Sand: 7.5%; Grass: 7.1%), drop jump from 88cm (Sand: 6.5%; Grass: 5.7%), and 15m sprint time (Sand: -2.2%; Grass: -2.3%). However, no significant difference was found between the two surfaces. In conclusion, 5-week PT on either sand or grass surfaces can improve sprint and jump performance in young soccer players.