Gastrocnemius Medialis Architectural Properties at Rest and During Stretching in Female Athletes with Different Flexibility Training Background

Background: This study examined gastrocnemius medialis (GM) architectural properties and ankle joint range of motion (ROM) between female athletes with different flexibility training background. Methods: Elite rhythmic gymnasts (n = 10) were compared to national level volleyball athletes (n = 10). Fascicle length, pennation angle and muscle thickness at the medial and the distal part of GM, and ankle ROM were measured at rest and during 1 min of static stretching. Results: At rest, rhythmic gymnasts displayed longer fascicles compared to volleyball athletes, at the medial (5.93 &plusmn
0.27 vs. 4.74 &plusmn
0.33 mm, respectively, p = 0.001) and the distal part of GM (5.63 &plusmn
0.52 vs. 4.57 &plusmn
0.51 mm, respectively, p = 0.001), smaller pennation angle at the medial part (22.4 &plusmn
2.5 vs. 25.8 &plusmn
2.4&deg
respectively, p = 0.001) and greater ankle angle (121.7 &plusmn
4.1 vs. 113.2 &plusmn
3.7&deg
respectively, p = 0.001). During the 1 min of static stretching, gymnasts displayed greater fascicle elongation at the distal part (p = 0.026), greater maximal ankle dorsiflexion (p &lt
0.001) and muscle tendon junction displacement (p &lt
0.001) with no difference between groups in pennation angles (p &gt
0.145), muscle thickness (p &gt
0.105), and fascicle elongation at mid-belly (p = 0.063). Conclusions: Longer muscle fascicles at rest and greater fascicle elongation at the distal part of GM may contribute to the greater ankle ROM observed in rhythmic gymnasts.