In vivo Sonographic Characterization of The Achilles Tendons in Healthy Young Collegiate Athletes as a Function of Ankle Position

Abstract

This study aims to describe the normative Achilles tendon properties in a collegiate subject cohort. Achilles tendon evaluations in 65 asymptomatic college-level athletes by ultrasound B mode on two tendon positions (neutral state and active maximum dorsiflexion). Correlation was made to BMI, tibial/foot length, maximal calf circumference, type of sports, resting/maximal dorsiflexion-plantar flexion angles among other factors. The mean Achilles tendon length was found to be 14.9 cm, mean transverse dimension of 1.38 cm, thickness of 0.49 cm and cross-sectional area of 0.61 cm2 in the relaxed state. Males had greater tendon length than the female athletes (15.5 (M) vs 14.3cm (F) in the relaxed position and 16.1 (M) vs 15.2cm (F) in the stretched position), tendon width (1.4 vs 1.3 cm), tendon thickness (0.51 vs 0.46 cm), tendon cross-sectional area (0.65 vs 0.57 cm2) and foot length (27.6 cm vs 26.6 cm). The Achilles tendon parameters such as length in the relaxed state had a statistically significant correlation with the height, weight, and foot length, while the tendon length in the dorsiflexed-stretched position had a statistically significant relationship to foot length, tibia length, calf circumference and range of motion (both in maximum dorsiflexion and plantar flexion positions; p < .05 for all comparison). Differences in the correlation between the Achilles tendon parameters and body habitus was recorded as a function of ankle position. Tendon dimensions and cross-sectional areas were larger in male vs female athletes. Calf circumferences and Achilles tendon resting angle were outlined. No significant difference was found in the Achilles tendon dimensions regardless of the leg dominance with similar range of motion regardless of athlete gender.