Landing
Define the force on which gymnasts can get rid of muscle force?
Gymnastics
Gymnastics Megalocephalus Muscle contraction Pennate muscle Architectural gear ratio
Gymnastics-Landing Megalocephalus-Skull Muscle_contraction-Force-length_and_force-velocity_relationships Pennate_muscle-Relationship_between_PCSA_and_muscle_force Architectural_gear_ratio-Abstract
In an aerial routine, or any form of tumbling, landing is the final phase, following take off and flight This is a critical skill in terms of execution in competition scores, general performance, and injury occurrence. Without the necessary magnitude of energy dissipation during impact, the risk of sustaining injuries during somersaulting increases. These injuries commonly occur at the lower extremities and include; cartilage lesions, ligament tears, and bone bruises/fractures. To avoid such injuries, and to receive a high performance score, proper technique must be used by the gymnast. "The subsequent ground contact or impact landing phase must be achieved using a safe, aesthetic and well-executed double foot landing." A successful landing in gymnastics is classified as soft, meaning the knee and hip joints are at greater than 63 degrees of flexion. A higher flight phase results in a higher vertical ground reaction force. Vertical ground reaction force represents external force which the gymnasts have to overcome with their muscle force and has an impact on the gymnasts linear and angular momentum. Another important variable that affects linear and angular momentum is time the landing takes Gymnasts can alter the shape of the area by increasing the time taken to perform the landing. Gymnasts can achieve this by increasing hip, knee and ankle amplitude. With the increase of height, the amplitude in ankles knees and hips rise the bars.
It is only known from its skull, like most other baphetids. The skull of "Megalocephalus" was long. The teeth of "Megalocephalus" were long and pointed. Baphetids had a small elongation of their eye sockets, of which the current use for is not certain. It has been suggested that the elongation was housing for a salt gland to get rid of excess salt, or a extra region for jaw muscle attachments, to allow a harder bite force. 
Unlike mechanical systems such as motors, the force a muscle can generate depends upon both the length and shortening velocity of the muscle. "Force-length relationship", also called the length-tension curve, relates the strength of an isometric contraction to the length of the muscle at which the contraction occurs. Muscles operate with greatest active force when close to an ideal length (often their resting length). When stretched or shortened beyond this (whether due to the action of the muscle itself or by an outside force), the maximum active force generated decreases. This decrease is minimal for small deviations, but the force drops off rapidly as the length deviates further from the ideal. As a result, in most biological systems, the range of muscle contraction will remain on the peak of the length-tension curve, in order to maximize contraction force (a notable exception is cardiac muscle which functions on ascending limb so it can increase force when stretched by an increase in the preload-Starling's law). Due to the presence of elastic proteins within a muscle (such as titin), as the muscle is stretched beyond a given length, there is an entirely passive force, which opposes lengthening. Combined together, we see a strong resistance to lengthening an active muscle far beyond the peak of active force. "Force–velocity relationship": The speed at which a muscle changes length (usually regulated by external forces, such as load or other muscles) also affects the force it can generate. Force declines in a hyperbolic fashion relative to the isometric force as the shortening velocity increases, eventually reaching zero at some maximum velocity. The reverse holds true for when the muscle is stretched – force increases above isometric maximum, until finally reaching an absolute maximum. This has strong implications for the rate at which muscles can perform mechanical work (power). Since power is equal to force times velocity, the muscle generates no power at either isometric force (due to zero velocity) or maximal velocity (due to zero force). Instead, the optimal shortening velocity for power generation is approximately one-third of maximum shortening velocity. These two fundamental properties of muscle have numerous biomechanical consequences, including limiting running speed, strength, and jumping distance and height. 
The total force exerted by the fibers along their oblique direction is proportional to PCSA. If the "specific tension" of the muscle fibers is known (force exerted by the fibers per unit of PCSA), it can be computed as follows: formula_3 However, only a component of that force can be used to pull the tendon in the desired direction. This component, which is the true "muscle force" (also called "tendon force"), is exerted along the direction of action of the muscle: formula_4 The other component, orthogonal to the direction of action of the muscle (Orthogonal force = Total force × sinΦ) is not exerted on the tendon, but simply squeezes the muscle, by pulling its aponeuroses toward each other. Notice that, although it is practically convenient to compute PCSA based on volume or mass and fiber length, PCSA (and therefore the total fiber force, which is proportional to PCSA) is not proportional to muscle mass or fiber length alone. Namely, the maximum (tetanic) force of a muscle fiber simply depends on its thickness (cross-section area) and type. By no means it depends on its mass or length alone. For instance, when muscle mass increases due to physical development during childhood, this may be only due to an increase in length of the muscle fibers, with no change in fiber thickness (PCSA) or fiber type. In this case, an increase in mass does not produce an increase in force. 
Architectural gear ratio, also called anatomical gear ratio (AGR) is a feature of pennate muscle defined by the ratio between the longitudinal strain of the muscle and muscle fiber strain. It is sometimes also defined as the ratio between muscle-shortening velocity and fiber-shortening velocity.AGR = εx/εfwhere εx = longitudinal strain (or muscle-shortening velocity) and εf is fiber strain (or fiber-shortening velocity)In fusiform muscle, the fibers are longitudinal, so longitudinal strain is equal to fiber strain, and AGR is always 1. As the pennate muscle is activated, the fibers rotate as they shorten and pull at an angle. In pennate muscles, fibers are oriented at an angle to the muscle's line of action and rotate as they shorten, becoming more oblique such that the fraction of force directed along the muscle's line of action decreases throughout a contraction. Force output is dependant upon the angle of fiber rotation, so changes in muscle thickness and the vector of change in thickness vary; based upon the force being produced. Due to the rotational motion; pennate muscles operate at low velocities (low shortening distance). The shortening velocity of the pennate muscle as a whole is greater than that of the individual fibers. This gives rise to the property of AGR. Fiber rotation decreases a muscle's output force but increases output velocity by allowing the muscle to function at a higher gear ratio (muscle velocity/fiber velocity). Azizi and Brainerd demonstrated that the gear ratio of pennate muscle can vary; dependant on external load. Segmented musculature, like pennate muscle, has fibers aligned at an angle and due to this feature of design, when muscle fibers increase in angle with respect to the medial axis, along with the direction and amount of muscle bulging, the Architectural gear ratio increases. A variable gear ratio, based upon different anatomical position, loading and movement conditions, has since been dubbed spatially varying gear ratio. The occurrence of spatially varying gear ratio gives rise to a new insight of muscle biology; “inhomogenous muscle mechanics.”One feature of the ratio is that there is an optimal gear ratio for each muscle; as the length-tension and force-velocity relationships describe. Length-tension refers to the max tension that can be created over the muscle fiber strain range and force-velocity refers to the power that is possible of the fiber compared to the shortening velocity. These two features of musculature help to define an optimal AGR for a muscle. 