The aim of this study was to determine the correlation between muscle thickness (MT) and cycling power in varsity cyclists using ultrasonography (US) and to identify any differences in MT between short- and long-distance cyclists. Twelve cyclists participated in this study. Real-time two-dimensional B-mode US was used to measure the MT in the anterior thigh, anterior lower leg, and trunk, especially in the abdominal and lumbar regions. A cycle ergometer was used to measure cycling power parameters such as maximum anaerobic power (over 5 s), mean anaerobic power (over 30 s), and aerobic power (over 3 min). This study was approved by the Ethics Committee of Korea National Sports University. There was a significant relationship between the MT and cycling power for the rectus femoris (RF) and vastus lateralis (VL) in the thigh, the rectus abdominis (RA) in the abdominal region, and the erector spinae (ES) in the lower back. The MT values of the RF, VL, and ES were strongly associated with the maximum and mean anaerobic power. There were significant differences between short- and long-distance cyclists in the MT of the RF in the thigh, the RA, the external abdominal oblique, the internal abdominal oblique, and the transverse abdominis muscle in the abdomen. We suggest that training programs attempting to improve cycling performance focus on improving the VL and ES via resistance weight or cycle training and also the core muscles for short-distance cyclists. Clin. Anat. 31:899–906, 2018.
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