This study compared the magnitude of muscle damage induced when consecutive drop jumps (DJs) were performed on sand vs. firm (wood) surfaces from a height of 0.6 m. Eight subjects performed DJs on a sand surface at a depth of 0.2 m (S condition), and 8 other subjects performed DJs on a wood surface (F condition). Each set consisted of 20 DJs with an interval of 10 seconds between jumps. Subjects performed 5 sets of DJs with 2 minutes between sets. Maximal isometric force, muscle soreness, and plasma creatine kinase (CK) activity were measured immediately before and immediately after the DJ exercise as well as 1, 24, 48, 72, and 96 hours after the DJ exercise. All measures changed significantly (p < 0.05) after exercise for both conditions; however, significantly (p < 0.05) smaller changes in these measures were evident for the S condition than for the F condition. These results show that DJs on a sand surface induce less muscle damage than on a firm surface. Training on sand may improve aerobic capacity or strength with a low risk of muscle damage.