Methods / Statistics

Document Type



The purpose of this study was to compare sagittal plane lower limb kinematics of underwater fly kick measured using two and three-dimensional methods. Eight male participants (average FINA points score 801±138) completed underwater fly kick trials, recorded using a six camera Qualisys underwater system. Each trial was analysed using both two and three-dimensional methods. Lower-limb angles were significantly underestimated using two-dimensional methods, particularly at the hip where flexion and range of motion reduced by 13.73 degrees and 15.91 degrees respectively. The ankle and hip produce a large amount motion in the transverse and frontal planes. The results of two-dimensional analyses of underwater fly kick should be interpreted with caution due reductions in measured angles, and exclusion of out-of-plane kinematic information.