The human iliotibial band is specialized for elastic energy storage compared with the chimp fascia lata

Abstract

This study examines whether the human iliotibial band (ITB) is specialized for elastic energy storage relative to the chimpanzee fascia lata (FL). To quantify the energy storage potential of these structures, we created computer models of human and chimpanzee lower limbs based on detailed anatomical dissections. We characterized the geometry and force-length properties of the FL, tensor fascia lata (TFL) and gluteus maximus (GMax) in four chimpanzee cadavers based on measurements of muscle architecture and moment arms about the hip and knee. We used the chimp model to estimate the forces and corresponding strains in the chimp FL during bipedal walking, and compared these data with analogous estimates from a model of the human ITB, accounting for differences in body mass and lower extremity posture. We estimate that the human ITB stores 15-to 20-times more elastic energy per unit body mass and stride than the chimp FL during bipedal walking. Because chimps walk with persistent hip flexion, the TFL and portions of GMax that insert on the FL undergo smaller excursions (origin to insertion) than muscles that insert on the human ITB. Also, because a smaller fraction of GMax inserts on the chimp FL than on the human ITB, and thus its mass-normalized physiological cross-sectional area is about three times less in chimps, the chimp FL probably transmits smaller muscle forces. These data provide new evidence that the human ITB is anatomically derived compared with the chimp FL and potentially contributes to locomotor economy during bipedal locomotion.

Foetal development of the human gluteus maximus muscle with special reference to its fascial insertion

“…With its strong fascial insertion in humans, the GMX plays a major role in maintaining the lateral stability of the pelvis during walking, rather than abduction and/or flexion. In non-human primates, the iliotibial tract may be present but it does not resemble that in humans [4].…”

Water-content related alterations in macro and micro scale tendon biomechanics

“…Contributing with the previous, a change in the water content will also influence the thickness of the collagen fibers 35,38,39 , making them more prone to stiffening and changes in their viscoelastic behavior at the hierarchical levels presented here. This functional relationship of the iliotibial band is in line with the tissue acting as a stabilizer for both the hip and knee joint, given effective two-leg propulsion requires a significant amount of energy storage and force regain capacity 40,41 . The interfascicular matrix of this tendon oversees its stretching and recoiling properties.…”

Phylogenetics of the Fascial System

“…The lateral part of the thigh is formed by a fibrous septum, the iliotibial tract, seen only in Homo sapiens, which leaves the lateral part of the tibia through the femur, where it is continuous with the fasciae of the gluteus maximus, gluteus medius, and tensor fascia lata (Figure 1 ). The iliotibial tract combined in its positional relationship with the gluteus fascia allowed to reduce the lateral trunk inclination in the single-legged support [ 13 ]. The gluteal fascia superiorly inserts itself into the thoracolumbar fascia, continuing the path of force transmission.…”

“…This was important for us to develop great movements of the scapular girdle and limbs. The upper limb fasciae have a unique organization, allowing for a wide range and diversity of movements [ 13 ]. The upper limb is adapted to work in open kinetic chain movements, different from the reality presented by quadrupeds.…”

“…The execution of eye movements in all directions and maintaining complete independence of the head and neck is an optimized feature in sapiens [ 26 ]. In addition to adaptations in the fascial system, through the Tenon capsule, there was an advanced neuromuscular control associated with changes in the eye structure itself [ 13 - 27 ].…”