Lower extremity joints and muscle groups in the human locomotor system alter mechanical functions to meet task demand

Abstract

To facilitate movement through mechanically complex environments, terrestrial animals have evolved locomotor systems capable of flexibly altering internal mechanics to meet external demands. They do this by shifting imposed workloads between joints/muscle groups (central mechanical flexibility) and/or by altering the function of individual joints/ muscle groups (local mechanical flexibility). In human locomotion research, central mechanical flexibility is well established and regularly reported. Local mechanical flexibility at major lower extremity joints and muscle groups, however, has received relatively less attention. We used an emerging biomechanical analysis known as functional indexing to test the hypothesis that lower extremity joints and muscle groups within the human locomotor system alter their mechanical function to meet altered locomotor demands. Thirteen healthy adults walked across a range of speeds (0.8, 1.2, 1.6, 2.0 m s −1 ) and slopes (0 deg, +5 deg, +10 deg) to determine whether hip, knee and ankle joints and their extensors and flexors altered their mechanical function in response to increased speed and slope. As walking speed increased, the knee and its extensors altered their function to behave more like mechanical springs while the ankle and its extensors altered their function to behave more like motors. As slope increased, all three joints and their extensors decreased spring-and damper-like behavior and increased motor-like behavior. Our results indicate that humanssimilarly to many other terrestrial animalsutilize local mechanical flexibility to meet the demands of the locomotor task at hand.

Speed-Related Energy Flow and Joint Function Change During Human Walking

“…From the previous researches (Cofré et al, 2011;Williams and Schache, 2016;Browne and Franz, 2018;Uematsu et al, 2018), ankle produces positive work during stance phase, which could be regarded as motor-like function. However, some studies regarded ankle as principle spring during walking (Lee et al, 2008;Qiao and Jindrich, 2016;Kuhman and Hurt, 2019). In this study, according to the functional behaviors and produced mechanical work of ankle during different phases, we show that ankle is dissipating mechanical energy during the first three phases (collision, rebound, and preload) and releasing mechanical energy during push-off.…”

“…Besides, slight changes occur in function indices with different walking speed. Kuhman and Hurt (2019) suggested that joints' functional behaviors during walking, especially for knee and ankle, were different under changed walking speed. The results in this study show that, strut function of knee during collision and push-off decreases with growing walking speed (seen in Table 3).…”

“…Joints make different functional contributions to achieve demanded movements, and may reduce energy exchange that could optimize walking economy when the speed changes. It requires the elastic potential properties of the musculotendon system to periodically absorb and generate energy in the stance phase (Cavagna, 1977;Kuitunen et al, 2002;Kuhman and Hurt, 2019). Dickinson (2000) described four basic functional behaviors perform (strut, spring, motor, and damper) based on the mechanical work.…”

The Effectiveness of Biological Maturation and Lean Mass in Relation to Muscle Strength Performance in Elite Young Athletes

“…The voluntary production of movements in the neuromuscular system activates the nervous and locomotor systems to perform tasks [9]. Movement occurs due to the interaction of muscle tissue with bone tissue, with measures of lean mass being the determining factor for the execution of body movement [10]. Increased volume of lean mass is also identified as a significant characteristic for physical health and sports performance [11,12].…”

Kinetic coupling in distal foot joints during walking

“…2 and 3 ). If some of this negative work represents strain energy storage that will subsequently be returned, the toe brace resulted in a more damper-like midtarsal joint, with a higher ratio of negative to positive work [ 20 ]. The apparent increase in negative work looked to be primarily a result of a prolonged negative power phase and delayed transition to positive power.…”