Gender Difference in Architectural and Mechanical Properties of Medial Gastrocnemius–Achilles Tendon Unit In Vivo

Abstract

This study aims to explore whether gender differences exist in the architectural and mechanical properties of the medial gastrocnemius–Achilles tendon unit (gMTU) in vivo. Thirty-six healthy male and female adults without training experience and regular exercise habits were recruited. The architectural and mechanical properties of the gMTU were measured via an ultrasonography system and MyotonPRO, respectively. Independent t-tests were utilized to quantify the gender difference in the architectural and mechanical properties of the gMTU. In terms of architectural properties, the medial gastrocnemius (MG)’s pennation angle and thickness were greater in males than in females, whereas no substantial gender difference was observed in the MG’s fascicle length; the males possessed Achilles tendons (ATs) with a longer length and a greater cross-sectional area than females. In terms of mechanical properties, the MG’s vertical stiffness was lower and the MG’s logarithmic decrement was greater in females than in males. Both genders had no remarkable difference in the AT’s vertical stiffness and logarithmic decrement. Gender differences of individuals without training experience and regular exercise habits exist in the architectural and mechanical properties of the gMTU in vivo. The MG’s force-producing capacities, ankle torque, mechanical efficiency and peak power were higher in males than in females. The load-resisting capacities of AT were greater and the MG strain was lesser in males than in females. These findings suggest that males have better physical fitness, speed and performance in power-based sports events than females from the perspective of morphology and biomechanics.

The Relation of Body Mass Index to Muscular Viscoelastic Properties in Normal and Overweight Individuals

“…We think that the BB and BF viscoelastic properties are affected by sex to a greater extent in males than females. Our results are consistent with those of other studies that reported higher gastrocnemius stiffness and lower elasticity in males than in females [36,37].…”

The relationship between muscle thickness and pennation angle is mediated by fascicle length in the muscles of the lower extremities

“…FL is influenced by factors such as tendon length, joint structure, limb proportions, and age 20 – 22 . Our study also highlighted sex differences in VL, GM, and GL regarding PA (i.e., males > females), which is also in line with the literature 17 , 23 , 24 . Males are taller than females, which has been genetically explained elsewhere 25 , 26 , so could that alone explain the differences in muscle architecture?…”

Myotonometry and extended field-of-view ultrasound imaging allow reliable quantification of patellar tendon stiffness and length at rest and during maximal load, whereas several restrictions exist for the Achilles tendon

“…Our study (Figures 3, 4) and previous studies reported MDCs for PT and AT stiffness and length measurements using the myotonometry method (12,13,15) and the EFOV-US technique (19,20), respectively. With regard to the results of previous studies investigating changes in PT and AT stiffness (31,(48)(49)(50)(51)(52)(53) and length (34, 36-38, 43, 44, 54) in sports and medicine, these changes could be detected outside the measurement error using myotonometry and the EFOV-US technique, which supports the practical applicability of both technologies. For future studies using the EFOV-US technique, and as conducted here, we recommend the usage of a fixable brace to avoid axial shifts of the US probe.…”