The lower extremity dexterity test as a measure of lower extremity dynamical capability

Lyle, Mark A.; Valero-Cuevas, Francisco J.; Gregor, Robert J.; Powers, Christopher M.

doi:10.1016/j.jbiomech.2012.11.058

Cited by 20 publications

(55 citation statements)

References 9 publications

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“…This test was originally developed for fingers[3, 5, 42], and then adapted into a lower extremity version to quantify the dynamical ability to stabilize unstable foot-ground interactions[19, 23]. …”

Section: Figurementioning

confidence: 99%

“…Namely, it is the ability to use movements and force vectors to stabilize a slender spring prone to buckling. It was originally developed for fingers[3, 5, 42], and then adapted into a lower extremity dexterity test to quantify the dynamical ability to stabilize unstable foot-ground interactions[19, 23]. We have previously reported sex differences in this leg version in young soccer players[22] and across the lifespan[19] and proposed that may contribute to the disproportionate higher number of non-contact ACL injuries in female athletes compared to males.…”

Section: Introductionmentioning

confidence: 99%

“…However, we have shown that different versions of the Valero-Cuevas dexterity test quantify the functional domain of sensorimotor processing, as distinct from the functional domains of strength and limb coordination, in fingers[3, 5, 19, 41] and legs[18] (Figure 1). This simple, yet reliable, test requires participants to compress a slender spring prone to buckling at low forces to a maximal steady state level[23, 41]. The spring becomes increasingly unstable as it is compressed (i.e., undergoes a bifurcation in instability[42]), and one’s ability to compress and hold the spring at the edge of instability is a measure of the person’s sensorimotor control capabilities[3, 5, 19, 41, 42].…”

Section: Introductionmentioning

confidence: 99%

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Sex differences in leg dexterity are not present in elite athletes

Lawrence

Peppoloni

Valero-Cuevas

2017

Journal of Biomechanics

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We studied whether the time-varying forces that control unstable foot-ground interactions provide insight into the neural control of dynamic leg function. Twenty elite (10F, 26.4±3.5yrs) and 20 recreational (10F, 24.8±2.4yrs) athletes used an isolated leg to maximally compress a slender spring designed to buckle at low forces while seated. The foot forces during the compression at the edge of instability quantify the maximal sensorimotor ability to control dynamic foot-ground interactions. Using the nonlinear analysis technique of attractor reconstruction, we characterized the spatial (interquartile range IQR) and geometric (trajectory length TL, volume V, and sum of edge lengths SE) features of the dynamical behavior of those force time series. ANOVA confirmed the already published effect of sex, and a new effect of athletic ability, respectively, in TL (p=0.014 and p<0.001), IQR (p=0.008 and p<0.001), V (p=0.034 and p=0.002), and SE (p=0.033 and p<0.001). Further analysis revealed that, for recreational athletes, females exhibited weaker corrective actions and greater stochasticity than males as per their greater mean values of TL (p=0.003), IQR (p=0.018), V (p=0.017), and SE (p=0.025). Importantly, sex differences disappeared in elite athletes. These results provide an empirical link between sex, athletic ability, and nonlinear dynamical control. This is a first step in understanding the sensorimotor mechanisms for control of unstable foot-ground interactions. Given that females suffer a greater incidence of non-contact knee ligament injuries, these non-invasive and practical metrics of leg dexterity may be both indicators of athletic ability, and predictors of risk of injury.

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Section: Figurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Sex differences in leg dexterity are not present in elite athletes

Lawrence

Peppoloni

Valero-Cuevas

2017

Journal of Biomechanics

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“…This ability was assessed using the Strength-Dexterity test adapted for the isolated leg (Neuromuscular Dynamics, LLC, La Crescenta, CA). Detailed description of the lower extremity dexterity (LED) test can be found elsewhere (Lyle et al, 2013; Lawrence et al, 2014). In short, this test evaluates participant's ability to compress a compliant and slender spring that is prone to buckling at low force magnitudes.…”

Section: Methodsmentioning

confidence: 99%

“…Successful performance of balance and locomotor tasks is mediated by the ability of the leg to control force vectors to regulate dynamic foot-ground interactions, which has been referred to as dexterity (Valero-Cuevas et al, 2003; Lyle et al, 2013; Lawrence et al, 2014). We define dexterity as per the Strength-Dexterity paradigm (Valero-Cuevas et al, 2003), where a limb attempts to fully compress a compliant and slender spring prone to buckling.…”

Section: Introductionmentioning

confidence: 99%

Unilateral Eccentric Contraction of the Plantarflexors Leads to Bilateral Alterations in Leg Dexterity

2016

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Eccentric contractions can affect musculotendon mechanical properties and disrupt muscle proprioception, but their behavioral consequences are poorly understood. We tested whether repeated eccentric contractions of plantarflexor muscles of one leg affected the dexterity of either leg. Twenty healthy male subjects (27.3 ± 4.0 yrs) compressed a compliant and slender spring prone to buckling with each isolated leg. The maximal instability they could control (i.e., the maximal average sustained compression force, or lower extremity dexterity force, LEDforce) quantified the dexterity of each leg. We found that eccentric contractions did not affect LEDforce, but reduced force variability (LEDSD). Surprisingly, LEDforce increased in the non-exposed, contralateral leg. These effects were specific to exposure to eccentric contractions because an effort-matched exposure to walking did not affect leg dexterity. In the exposed leg, eccentric contractions (i) reduced voluntary error corrections during spring compressions (i.e., reduced 0.5–4 Hz power of LEDforce); (ii) did not change spinal excitability (i.e., unaffected H-reflexes); and (iii) changed the structure of the neural drive to the α-motoneuron pool (i.e., reduced EMG power within the 4–8 Hz physiological tremor band). These results suggest that repeated eccentric contractions alter the feedback control for dexterity in the exposed leg by reducing muscle spindle sensitivity. Moreover, the unexpected improvement in LEDforce in the non-exposed contralateral leg was likely a consequence of crossed-effects on its spinal and supraspinal feedback control. We discuss the implications of these bilateral effects of unilateral eccentric contractions, their effect on spinal and supraspinal control of dynamic foot-ground interactions, and their potential to facilitate rehabilitation from musculoskeletal and neuromotor impairments.

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Establishing metrics and control laws for the learning process: ball and beam balancing

Buza

Milton

Bencsik³

et al. 2020

Biol Cybern

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Understanding how dexterity improves with practice is a fundamental challenge of motor control and neurorehabilitation. Here we investigate a ball and beam implementation of a dexterity puzzle in which subjects stabilize a ball at the mid-point of a beam by manipulating the angular position of the beam. Stabilizability analysis of different biomechanical models for the ball and beam task with time-delayed proportional-derivative feedback identified the angular position of the beam as the manipulated variable. Consequently, we monitored the changes in the dynamics with learning by measuring changes in the control parameters. Two types of stable motion are possible: node type (nonoscillatory) and spiral type (oscillatory). Both types of motion are observed experimentally and correspond to well-defined regions in the parameter space of the control gains. With practice the control gains for each subject move close to or on the portion of the boundary which separates the node-type and spiral-type solutions and which is associated with the rightmost characteristic exponent of smallest real part. These observations suggest that with learning the control gains for ball and beam balancing change in such a way that minimizes overshoot and the settling time. This study provides an example of how mathematical analysis together with careful experimental observations can shed light onto the early stages of skill acquisition. Since the difficulty of this task depends on the length of the beam, ball and beam balancing tasks may be useful for the rehabilitation of children with dyspraxia and those recovering from a stroke. Keywords Human balancing • Reaction time • Visual feedback • Motor control • Learning Communicated by Benjamin Lindner.

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The lower extremity dexterity test as a measure of lower extremity dynamical capability

Cited by 20 publications

References 9 publications

Sex differences in leg dexterity are not present in elite athletes

Sex differences in leg dexterity are not present in elite athletes

Unilateral Eccentric Contraction of the Plantarflexors Leads to Bilateral Alterations in Leg Dexterity

Establishing metrics and control laws for the learning process: ball and beam balancing

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