The assessment of mechanical and neuromuscular response strategies during landing

Neuromechanical synergies in single-leg landing reveal changes in movement control

“…This movement strategy has been observed previously (Devita & Skelly, 1992;Dufek & Bates, 1990;Dufek & Zhang, 1996), decreasing effective landing height and accommodating loads under greater mechanical task demands (Caster & Bates, 1995). The ankle joint appeared to absorb energy prior to the hip and knee joints, with subjects using greater medial gastrocnemius muscle activation in early landing (Iida, Kanehisa, Inaba, & Nakazawa, 2011;Lyle, Valero-Cuevas, Gregor, & Powers, 2014;Santello & McDonagh, 1998).…”

“…8), which we interpreted in the context of decreased movement variability and fewer available functional DOF among lower-extremity joints. We attributed the observed movement strategies to constraints imposed by the landing task (Caster & Bates, 1995;James et al, 2003;James et al, 2014). Lesser movement variability therefore appeared to be accomplished via synergistic associations among patterns of muscle activation, applied loads, and segmental configurations (Kipp et al, , 2014Latash, 2010;Li, 2006;Lohse et al, 2013;Turvey, 1990).…”

“…Synergistic control of human movement has been experimentally identified in balance, gait, and landing, describing not only the correlation structure among movement outcomes (Diedrichsen et al, 2009), but also the neural activation patterns controlling movement (Chvatal & Ting, 2012;Kipp et al, 2014). Mechanical and neuromuscular adjustments following mechanical task demand manipulations, including load and landing height, provide mechanisms for load accommodation, moderating external forces (Caster & Bates, 1995;James et al, 2003), and potentially altering movement control through neuromuscular input. Lesser gross motor variability, expressed through fewer neuromechanical synergies, may therefore provide fewer available motor solutions under greater mechanical task demands, leading to repetitive tissue loading and possible overuse injury, as the rate of mechanical breakdown exceeds the rate of physiological repair (James, 2004;James et al, 2000).…”

Review of motor control mechanisms underlying impact absorption from falls

“…Specifically, a larger degree of ankle plantar flexion was found when landing onto hard rather than soft surfaces, resulting in larger ankle joint excursion after foot contact. The fact that this kinematic adjustment to landing surface compliance was found only in skilled subjects strongly suggests that practice and skill play a significant role in determining the strategy used to control landing movements, as also revealed by the work of several other authors [3,[50][51][52][53].…”

Gender Differences in Knee Angle on Landing from a Drop-Jump: Kinematic Data in Young Adults

“…Huston et al 12) theorized that the smaller knee flexion angle utilized by women during the impact phase of landing would also increase their vertical ground reaction forces and knee joint loads. Landing imposes forces on the body that must be absorbed primarily by the lower extremity 5) . If loads become too great for the body to accommodate or if impact absorption fails, an injury is likely 17) .…”