This Protein is Why Eccentric Muscle Contraction is Stronger

The Titin Protein is Why Eccentric Muscle Contraction is Stronger. During eccentric contraction when an active muscle fiber or myofibril is actively stretched, its force increases substantially during the stretch. Some of this extra force that develops during stretch decays when stretching stops, but the force that remains after stretching stops is substantially higher than the isometric force at the stretched length. This residual force persists until the muscle is returned to its initial length or is deactivated. Cross-bridge models account for the increased force during stretch by assuming that cross-bridges are elastic and store energy when stretched. Various additions to the cross-bridge model have been proposed to account for the increased force during stretch, including rapid detachment and reattachment of cross bridges and tension-dependent rearrangement of the thick filaments. Although these studies argue that cross-bridges alone may explain the magnitude of force enhancement, increasing evidence suggests that titin is the primary reason for increased eccentric contractile force. Cross-bridges alone cannot account for energy absorption during active stretch. Even after accounting for tendon, thick filament, thin filament, and passive titin elasticity, only about 34% of the absorbed energy could be explained. The extra tension that remains after stretch is due to titin. Most of the absorbed energy during stretch is stored in non-cross bridge structures, mainly titin. Want to learn more about muscle contraction, mitochondria, Metabolic energy, and the titin protein? Check out our online, board-certified and accredited continuing education courses here: https://intricateartseminars.com/course/muscle-metabolic-energy-courses/ Subscribe to my YouTube Channel here: https://www.youtube.com/channel/UC66zKmIQiuxoqOURh5MKNRQ?sub_confirmation=1