Gastrocnemius muscle architecture in elite basketballers and cyclists: a cross-sectional cohort study - Datasets

Full description

A trained sonographer obtained three B-mode ultrasound images from gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) muscles in 44 athletes (25 basketballers and 19 cyclists; 24±5 years of age).
The images were digitized and average fascicle length (FL), pennation angle (θ)
and muscle thickness were calculated from three images per muscle. The ratio of
FL to tibial length (FL/TL) and muscle thickness to tibial length (MT/TL) were
also calculated to account for the potential scaling effect of stature.

Body mass was measured to the
nearest 0.1 kg using a calibrated analogue floor-scale (Model 762; Seca,
Germany), and stretch stature was measured to the nearest 0.1 cm using a
portable stadiometer (Model 213; Seca; Germany) according to the procedures
described by the International Society for the Advancement of Kinanthropometry. Tibial length was estimated
using validated regression equations based on stature. Skeletal muscle
architecture of the GL and GM muscles at rest, was measured using 2-dimensional
B-mode ultrasound (LOGIQ V2; GE Healthcare, Australia), with a 38 mm wide
linear probe and a standardized frequency of 12-13 MHz.

Each participant lay prone on an examination table and an incline foam
wedge was used to support their flexed knee up to 30° to ensure the
gastrocnemius muscle was relaxed at the knee joint. A custom splint secured the
ankle joint close to 90° where the sole of the foot is perpendicular to the
tibia. This position was confirmed with a manual goniometer and a position
within the range of 85° to 95° was accepted. The sonographer identified the
probe site at one-third of the distance from the popliteal crease of the knee
to the tip of the medial malleolus for the GM, and the lateral malleolus for
the GL. The transducer
probe was positioned perpendicular to the long axis of the leg, at the midpoint
of the GL and GM muscle bellies, found at the center of each muscle halfway
between its medial and lateral borders. Three ultrasound
images were captured from each GM and GL at the left and right limb within one
session, totaling 12 images per participant. These images were recorded
digitally and sent to an external investigator for de-identification and randomization
(www.randomizer.org). The de-identified and randomised images were analyzed
using novel computer software designed in LabVIEW (version 16; National
Instruments, USA). One investigator performed the digitisation of the blinded
images, and from each image, three fascicles, three θs and a single measure of
muscle thickness were calculated. As three images were taken per muscle, this gave
a total of nine FLs, nine θs, and three measures of muscle thickness for each
muscle belly. From these, the average was calculated.