METHODS: A total of 78 first-year students from a public university in Henan Province were recruited for this study via a cluster randomized controlled trial (CRCT) design. The participants were divided into an experimental group (blended learning) and a control group (traditional learning). The intervention lasted for 16 weeks, and physical fitness indices such as body mass index (BMI), lung capacity, sit and reach, pull-ups/sit-ups, standing long jumps, 50-meter runs, and 1000/800-meter runs were measured before and after the intervention. Statistical analyses were conducted via generalized estimating equation (GEE) modeling, with the significance level set at P
METHODS: Twenty-three collegiate male soccer players (22.1±1.7 years) were tested in four conditions; vertical jump (VJ), vertical jump immediately after slow running (VJSR), vertical jump immediately after sprinting (VJFR) and double horizontal jump immediately after sprinting (HJFR). The kinematics and kinetics data were measured using Vicon motion analyzer (100Hz) and two Kistler force platforms (1000Hz), respectively.
RESULTS: For knee flexion joint angle, (p = 0.014, η = 0.15) and knee valgus moment (p = 0.001, η = 0.71) differences between condition in the landing phase were found. For knee valgus joint angle, a main effect between legs in the jumping phase was found (p = 0.006, η = 0.31), which suggests bilateral deficit existed between the right and left lower limbs.
CONCLUSION: In brief, the important findings were greater knee valgus moment and less knee flexion joint angle proceeding sprint (HJFR & VJFR) rather than no sprint condition (VJ) present an increased risk for knee injuries. These results seem to suggest that running and sudden subsequent jumping-landing activity experienced during playing soccer may negatively change the knee valgus moment. Thus, sprinting preceding a jump task may increase knee risk factors such as moment and knee flexion joint angle.