Advanced Age Redistributes Positive but Not Negative Leg Joint Work during Walking

Waanders, Jeroen B; Hortobágyi, Tibor; Murgia, Alessio; DeVita, Paul; Franz, Jason R.

doi:10.1249/mss.0000000000001828

Cited by 22 publications

(30 citation statements)

References 44 publications

(68 reference statements)

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“…To combat ankle joint rotation, we instructed subjects to keep their foot firmly fixed to on the dynamometer pedal, and secured the foot and leg using Velcro straps. During isometric trials, we measured that undesired heel-lift resulted in an ankle rotation of less than 5 degrees -an outcome fully consistent with that from other groups 27 .…”

Section: Subjects and Protocolsupporting

confidence: 78%

Activation-Dependent Changes in Soleus Length–Tension Behavior Augment Ankle Joint Quasi-Stiffness

Clark

Franz

2019

Journal of Applied Biomechanics

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The triceps surae muscle-tendon units are important in governing walking performance, acting to regulate mechanical behavior of the ankle through interaction between active muscle and passive elastic structures. Ankle joint quasi-stiffness (the slope of the relation between ankle moment and ankle rotation, k A), is a useful aggregate measure of this mechanical behavior. However, the role of muscle activation and length-tension behavior in augmenting k A remains unclear. Here, 10 subjects completed eccentric isokinetic contractions at rest and at two soleus activation levels (25% and 75% isometric voluntary contraction-IVC) prescribed using electromyographic biofeedback. Ultrasound imaging quantified activation-dependent modulation of soleus muscle length-tension behavior and its role in augmenting k A. We found that soleus muscle stiffness (k M) and k A exhibit non-linear relations with muscle activation and were both more sensitive to the onset of activation than to subsequent increases in activation. Our findings also suggest that k A can be modulated via activation through changes in soleus muscle length-tension behavior. However, this modulation is more complex than previously appreciated-reflecting interaction between active muscle and passive elastic tissues. Our findings may have implications for understanding normal and pathological ankle joint function and the design of impedance-based prostheses.

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Section: Subjects and Protocolsupporting

confidence: 78%

Activation-Dependent Changes in Soleus Length–Tension Behavior Augment Ankle Joint Quasi-Stiffness

Clark

Franz

2019

Journal of Applied Biomechanics

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“…The age-related decrease in common neural input occurred in synergistic lower extremity muscles. Curiously, such decreases seem not to be related to the age-typical reductions in mechanical output at the ankle and the increases in mechanical work generation at the hip joint 6 . Reduced RF-VL, TA-PL, and GL-SL beta-band coherence in older vs. younger adults may be related to general age-related reductions in the common neural drive via corticospinal tracks to synergistic muscle pairs during treadmill walking.…”

Section: Discussionmentioning

confidence: 87%

“…The age-related modifications in neuromuscular control are evidenced, among others, by the 40–50% increases in rectus (RF)-biceps femoris (BF) coactivation at heel strike during gait 3 – 5 . These alterations in neuromuscular control during gait are usually associated with age-related reductions in mechanical output at the ankle and increases in mechanical work generation at the hip joint 6 . Age-specific decreases in inhibitory cortical control are accompanied by decreases in Ia afferent input 7 that may lead to a depression of the inputs from muscle afferents compensated by increases in coactivation between agonist and antagonistic muscles during gait 3 , 4 .…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, we determined the effects of age on beta-band coherence during treadmill walking before and after experimentally induced fatigability. Based on age-typical distal to proximal reductions in mechanical work generation during treadmill walking 6 , we hypothesized that older compared with young adults would exhibit lower coherences in ankle muscles and higher coherences in muscles involved in hip flexion and extension. Concerning rSTS effects, we expected to find that muscle fatigability would strengthen coherence more in healthy younger compared with older adults in synergistic and antagonistic muscles around the ankle and knee joints during gait.…”

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confidence: 99%

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Age-specific modulation of intermuscular beta coherence during gait before and after experimentally induced fatigue

Santos

Lamoth

Barbieri

et al. 2020

Sci Rep

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We examined the effects of age on intermuscular beta-band (15–35 Hz) coherence during treadmill walking before and after experimentally induced fatigue. Older (n = 12) and younger (n = 12) adults walked on a treadmill at 1.2 m/s for 3 min before and after repetitive sit-to-stand, rSTS, to induce muscle fatigability. We measured stride outcomes and coherence from 100 steps in the dominant leg for the synergistic (biceps femoris (BF)-semitendinosus, rectus femoris (RF)-vastus lateralis (VL), gastrocnemius lateralis (GL)-Soleus (SL), tibialis anterior (TA)-peroneus longus (PL)) and for the antagonistic (RF-BF and TA-GL) muscle pairs at late swing and early stance. Older vs. younger adults had 43–62% lower GL-SL, RF-VL coherence in swing and TA-PL and RF-VL coherence in stance. After rSTS, RF-BF coherence in late swing decreased by ~ 20% and TA-PL increased by 16% independent of age (p = 0.02). Also, GL-SL coherence decreased by ~ 23% and increased by ~ 23% in younger and older, respectively. Age affects the oscillatory coupling between synergistic muscle pairs, delivered presumably via corticospinal tracts, during treadmill walking. Muscle fatigability elicits age-specific changes in the common fluctuations in muscle activity, which could be interpreted as a compensation for muscle fatigability to maintain gait performance.

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“…For example, advanced age is associated with decreased mechanical output from the ankle extensors and increased mechanical output from the hip extensors and/or flexors (DeVita and Hortobagyi, 2000;Franz and Kram, 2014;Kuhman et al, 2018b;Silder et al, 2008). Furthermore, the magnitude of this distal-to-proximal shift in joint-level mechanical output is larger during maximal compared with comfortable speed walking and during uphill compared with level-ground walking (Kuhman et al, 2018a,b;Waanders et al, 2018). It is possible that age-related biological changes to the extensors (e.g.…”

Section: Potential Consequences Of Reduced Mechanical Flexibilitymentioning

confidence: 99%

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

Kuhman

Hurt

2019

Journal of Experimental Biology

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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.

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Advanced Age Redistributes Positive but Not Negative Leg Joint Work during Walking

Abstract: Supplemental digital content is available in the text.

Cited by 22 publications

References 44 publications

Activation-Dependent Changes in Soleus Length–Tension Behavior Augment Ankle Joint Quasi-Stiffness

Activation-Dependent Changes in Soleus Length–Tension Behavior Augment Ankle Joint Quasi-Stiffness

Age-specific modulation of intermuscular beta coherence during gait before and after experimentally induced fatigue

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

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