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  1. Article ; Online: Habitual endurance running does not mitigate age-related differences in gait kinetics.

    Krupenevich, Rebecca L / Miller, Ross H

    Experimental gerontology

    2021  Volume 147, Page(s) 111275

    Abstract: Older adults often walk with smaller ankle joint kinetics and larger hip joint kinetics compared to young adults. These age-related differences have been attributed, in part, to weaker plantarflexor muscles. While it is thought that regular physical ... ...

    Abstract Older adults often walk with smaller ankle joint kinetics and larger hip joint kinetics compared to young adults. These age-related differences have been attributed, in part, to weaker plantarflexor muscles. While it is thought that regular physical activity helps to maintain muscle strength and mobility in older adults, physical activity levels on average decline with age. Therefore, understanding the effect of physical activity level on gait kinetics is an important objective for the management of mobility impairment in older adults. The purpose of this study was determine the effect of habitual endurance running on lower-extremity joint kinetics. 12 male older long-term runners (67 ± 5 yrs., 1.79 ± 0.07 m, 77.3 ± 13.7 kg) and 12 male older non-runners (70 ± 3 yrs., 1.78 ± 0.06 m, 79.68 ± 10.6 kg), performed overground walking trials at 1.3 m/s while kinematic and kinetic data were collected. Participants also performed maximal voluntary contractions at the hip, knee, and ankle joints on an isokinetic dynamometer. Older runners displayed similar ankle plantarflexor strength, similar hip extensor strength, and greater knee extensor strength compared to older non-runners, and walked with similar ankle joint kinetics (p > 0.05), and larger hip joint kinetics compared to older non-runners (p < 0.05). Thus, physical activity, in the form of running at least 20 miles/wk. and training for at least one race per year, did not mitigate the characteristic age-related differences in gait kinetics. Our findings may indicate that age-related differences in lower-extremity gait kinetics are a normal consequence of natural aging.
    Language English
    Publishing date 2021-02-05
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 390992-x
    ISSN 1873-6815 ; 0531-5565
    ISSN (online) 1873-6815
    ISSN 0531-5565
    DOI 10.1016/j.exger.2021.111275
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: American Society of Biomechanics Journal of Biomechanics Award 2021: Exploring the Functional Boundaries and Metabolic Consequences of Triceps Surae Force-Length Relations during Walking.

    Funk, Callum J / Krupenevich, Rebecca L / Sawicki, Gregory S / Franz, Jason R

    Journal of biomechanics

    2023  Volume 158, Page(s) 111771

    Abstract: The relationship between individual muscle dynamics and whole-body metabolic cost is not well established. Here we use biofeedback to modulate triceps surae (TS) activity during walking to test the following hypotheses based on basic principles of muscle ...

    Abstract The relationship between individual muscle dynamics and whole-body metabolic cost is not well established. Here we use biofeedback to modulate triceps surae (TS) activity during walking to test the following hypotheses based on basic principles of muscle physiology: (1) increased TS activity would increase metabolic cost via shorter muscle fascicle lengths and thus reduced force capacity and (2) decreased TS activity would decrease metabolic cost via longer muscle fascicle lengths and thus increased force capacity. 23 young adults walked on an instrumented treadmill at 1.25 m/s using electromyographic (EMG) biofeedback to match targets corresponding to ±20 and ±40% TS activity during push-off (late stance). B-mode ultrasound imaged the medial gastrocnemius (MG). Participants increased net metabolic power up to 85% and 21% when targeting increased and decreased TS activity, respectively (p < 0.001). At the instant of peak gastrocnemius force, MG fascicle length was 7% shorter (p < 0.001) and gastrocnemius force was 6% larger (p < 0.001) when targeting + 40% TS activity. Fascicle length was 3% shorter (p = 0.004) and force was 7% lower (p = 0.010) when targeting -40% TS activity; participants were unable to achieve decreased activation targets. MG fascicle length and activity mediated 11.7% (p = 0.036) and 57.2% (p = 0.006) of the changes in net metabolic power, respectively. MG force did not mediate changes in net metabolic power (p = 0.948). These findings suggest that changes in the functional operating length of muscle, induced here by volitional changes in TS activity, mediated changes in the metabolic cost of walking, relatively independently of force. Thus, shifts to shorter fascicle lengths (e.g., aging) may mediate activity-induced increases in metabolic cost.
    MeSH term(s) Young Adult ; Humans ; Biomechanical Phenomena ; Walking ; Muscles ; Biofeedback, Psychology ; Awards and Prizes
    Language English
    Publishing date 2023-08-21
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 218076-5
    ISSN 1873-2380 ; 0021-9290
    ISSN (online) 1873-2380
    ISSN 0021-9290
    DOI 10.1016/j.jbiomech.2023.111771
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Medial knee cartilage is unlikely to withstand a lifetime of running without positive adaptation: a theoretical biomechanical model of failure phenomena.

    Miller, Ross H / Krupenevich, Rebecca L

    PeerJ

    2020  Volume 8, Page(s) e9676

    Abstract: Runners on average do not have a high risk of developing knee osteoarthritis, even though running places very high loads on the knee joint. Here we used gait analysis, musculoskeletal modeling, and a discrete-element model of knee contact mechanics to ... ...

    Abstract Runners on average do not have a high risk of developing knee osteoarthritis, even though running places very high loads on the knee joint. Here we used gait analysis, musculoskeletal modeling, and a discrete-element model of knee contact mechanics to estimate strains of the medial knee cartilage in walking and running in 22 young adults (age 23 ± 3 years). A phenomenological model of cartilage damage, repair, and adaptation in response to these strains then estimated the failure probability of the medial knee cartilage over an adult lifespan (age 23-83 years) for 6 km/day of walking vs. walking and running 3 km/day each. With no running, by age 55 the cumulative probability of medial knee cartilage failure averaged 36% without repair and 13% with repair, similar to reports on incidence of knee osteoarthritis in non-obese adults with no knee injuries, but the probability for running was very high without repair or adaptation (98%) and remained high after including repair (95%). Adaptation of the cartilage compressive modulus, cartilage thickness, and the tibiofemoral bone congruence in response to running (+1.15 standard deviations of their baseline values) was necessary for the failure probability of walking and running 3 km/day each to equal the failure probability of walking 6 km/day. The model results suggest two conclusions for further testing: (i) unlike previous findings on the load per unit distance, damage per unit distance on the medial knee cartilage is greater in running vs. walking, refuting the "cumulative load" hypothesis for long-term joint health; (ii) medial knee cartilage is unlikely to withstand a lifetime of mechanical loading from running without a natural adaptation process, supporting the "cartilage conditioning" hypothesis for long-term joint health.
    Language English
    Publishing date 2020-08-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2703241-3
    ISSN 2167-8359
    ISSN 2167-8359
    DOI 10.7717/peerj.9676
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Effects of Self-Selected Step Length and Trunk Position on Joint Kinetics in Highly Physically Fit Older Adults.

    Krupenevich, Rebecca L / Miller, Ross H

    Journal of applied biomechanics

    2020  Volume 36, Issue 3, Page(s) 156–162

    Abstract: The causes of age-related differences in lower-extremity joint moments and powers are unknown. The purpose of this study was to determine the effects of highly physically active older adults walking with (1) a step length similar to young adults and (2) ... ...

    Abstract The causes of age-related differences in lower-extremity joint moments and powers are unknown. The purpose of this study was to determine the effects of highly physically active older adults walking with (1) a step length similar to young adults and (2) an upright trunk posture, on hip and ankle joint kinetics. The authors hypothesized that, compared with their self-selected walking mechanics, older adults would exhibit decreased hip kinetics and increased ankle kinetics when prescribed a young adult step length, and would exhibit decreased hip extension moments when maintaining an upright trunk posture during walking. A total of 12 active older adults (67 [5] y) and 13 active young adults (21 [3] y) walked at 1.3 m/s. The older adults also walked at 1.3 m/s with step lengths prescribed from height-matched young adults and, in a separate condition, walked with an upright trunk. The older adults did not display larger ankle kinetics or smaller hip kinetics in either condition compared to walking with a self-selected step length. These findings indicate that step length and trunk position do not primarily contribute to age-related differences in kinetics in highly active older adults and should serve as a starting point for investigating alternative explanations.
    Language English
    Publishing date 2020-04-07
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1145288-2
    ISSN 1543-2688 ; 1065-8483
    ISSN (online) 1543-2688
    ISSN 1065-8483
    DOI 10.1123/jab.2019-0092
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Automated analysis of medial gastrocnemius muscle-tendon junction displacements in heathy young adults during isolated contractions and walking using deep neural networks.

    Krupenevich, Rebecca L / Funk, Callum J / Franz, Jason R

    Computer methods and programs in biomedicine

    2021  Volume 206, Page(s) 106120

    Abstract: Background and objective: Direct measurement of muscle-tendon junction (MTJ) position is important for understanding dynamic tendon behavior and muscle-tendon interaction in healthy and pathological populations. Traditionally, obtaining MTJ position ... ...

    Abstract Background and objective: Direct measurement of muscle-tendon junction (MTJ) position is important for understanding dynamic tendon behavior and muscle-tendon interaction in healthy and pathological populations. Traditionally, obtaining MTJ position during functional activities is accomplished by manually tracking the position of the MTJ in cine B-mode ultrasound images - a laborious and time-consuming process. Recent advances in deep learning have facilitated the availability of user-friendly open-source software packages for automated tracking. However, these software packages were originally intended for animal pose estimation and have not been widely tested on ultrasound images. Therefore, the purpose of this paper was to evaluate the efficacy of deep neural networks to accurately track medial gastrocnemius MTJ positions in cine B-mode ultrasound images across tasks spanning controlled loading during isolated contractions to physiological loading during treadmill walking.
    Methods: Cine B-mode ultrasound images of the medial gastrocnemius MTJ were collected from 15 subjects (6M/9F, 23 yr, 71.9 kg, 1.8 m) during treadmill walking at 1.25 m/s and during maximal voluntary isometric plantarflexor contractions (MVICs). Five deep neural networks were trained using 480 manually-labeled images collected during walking, defined as the ground truth, and were then used to predict MTJ position in images from novel subjects: 1) during walking (novel-subject) and 2) during MVICs (novel-condition).
    Results: We found an average mean absolute error of 1.26±1.30 mm and 2.61±3.31 mm between the ground truth and predicted MTJ positions in the novel-subject and novel-condition evaluations, respectively.
    Conclusions: Our results provide support for the use of open-source software for creating deep neural networks to reliably track MTJ positions in B-mode ultrasound images. We believe this approach to MTJ position tracking is an accessible and time-saving solution, with broad applications for many fields, such as rehabilitation or clinical diagnostics.
    MeSH term(s) Biomechanical Phenomena ; Humans ; Muscle, Skeletal/diagnostic imaging ; Neural Networks, Computer ; Tendons/diagnostic imaging ; Ultrasonography ; Walking ; Young Adult
    Language English
    Publishing date 2021-04-27
    Publishing country Ireland
    Document type Journal Article
    ZDB-ID 632564-6
    ISSN 1872-7565 ; 0169-2607
    ISSN (online) 1872-7565
    ISSN 0169-2607
    DOI 10.1016/j.cmpb.2021.106120
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Reduced Achilles tendon stiffness in aging persists at matched activations and associates with higher metabolic cost of walking.

    Franz, Jason R / Krupenevich, Rebecca L / Gray, Aubrey J / Batsis, John A / Sawicki, Gregory S

    bioRxiv : the preprint server for biology

    2023  

    Abstract: The mechanisms responsible for increased walking metabolic cost among older adults are poorly understood. We recently proposed a theoretical premise by which age-related reductions in Achilles tendon stiffness ( ... ...

    Abstract The mechanisms responsible for increased walking metabolic cost among older adults are poorly understood. We recently proposed a theoretical premise by which age-related reductions in Achilles tendon stiffness (k
    Language English
    Publishing date 2023-11-27
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.11.27.568808
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Reduced Achilles Tendon Stiffness Disrupts Calf Muscle Neuromechanics in Elderly Gait.

    Krupenevich, Rebecca L / Beck, Owen N / Sawicki, Gregory S / Franz, Jason R

    Gerontology

    2021  Volume 68, Issue 3, Page(s) 241–251

    Abstract: Older adults walk slower and with a higher metabolic energy expenditure than younger adults. In this review, we explore the hypothesis that age-related declines in Achilles tendon stiffness increase the metabolic cost of walking due to less economical ... ...

    Abstract Older adults walk slower and with a higher metabolic energy expenditure than younger adults. In this review, we explore the hypothesis that age-related declines in Achilles tendon stiffness increase the metabolic cost of walking due to less economical calf muscle contractions and increased proximal joint work. This viewpoint may motivate interventions to restore ankle muscle-tendon stiffness, improve walking mechanics, and reduce metabolic cost in older adults.
    MeSH term(s) Achilles Tendon/physiology ; Aged ; Ankle/physiology ; Ankle Joint/physiology ; Biomechanical Phenomena/physiology ; Gait/physiology ; Humans ; Muscle, Skeletal/physiology ; Walking/physiology
    Language English
    Publishing date 2021-07-16
    Publishing country Switzerland
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ZDB-ID 193798-4
    ISSN 1423-0003 ; 0304-324X
    ISSN (online) 1423-0003
    ISSN 0304-324X
    DOI 10.1159/000516910
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Older Adults Overcome Reduced Triceps Surae Structural Stiffness to Preserve Ankle Joint Quasi-Stiffness During Walking.

    Krupenevich, Rebecca L / Clark, William H / Sawicki, Gregory S / Franz, Jason R

    Journal of applied biomechanics

    2020  Volume 36, Issue 4, Page(s) 209–216

    Abstract: Ankle joint quasi-stiffness is an aggregate measure of the interaction between triceps surae muscle stiffness and Achilles tendon stiffness. This interaction may be altered due to age-related changes in the structural properties and functional behavior ... ...

    Abstract Ankle joint quasi-stiffness is an aggregate measure of the interaction between triceps surae muscle stiffness and Achilles tendon stiffness. This interaction may be altered due to age-related changes in the structural properties and functional behavior of the Achilles tendon and triceps surae muscles. The authors hypothesized that, due to a more compliant of Achilles' tendon, older adults would exhibit lower ankle joint quasi-stiffness than young adults during walking and during isolated contractions at matched triceps surae muscle activations. The authors also hypothesized that, independent of age, triceps surae muscle stiffness and ankle joint quasi-stiffness would increase with triceps surae muscle activation. The authors used conventional gait analysis in one experiment and, in another, electromyographic biofeedback and in vivo ultrasound imaging applied during isolated contractions. The authors found no difference in ankle joint quasi-stiffness between young and older adults during walking. Conversely, this study found that (1) young and older adults modulated ankle joint quasi-stiffness via activation-dependent changes in triceps surae muscle length-tension behavior and (2) at matched activation, older adults exhibited lower ankle joint quasi-stiffness than young adults. Despite age-related reductions during isolated contractions, ankle joint quasi-stiffness was maintained in older adults during walking, which may be governed via activation-mediated increases in muscle stiffness.
    Language English
    Publishing date 2020-06-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1145288-2
    ISSN 1543-2688 ; 1065-8483
    ISSN (online) 1543-2688
    ISSN 1065-8483
    DOI 10.1123/jab.2019-0340
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Mechanics and energetics of human feet: a contemporary perspective for understanding mobility impairments in older adults.

    Takahashi, Kota Z / Krupenevich, Rebecca L / Lenz, Amy L / Kelly, Luke A / Rainbow, Michael J / Franz, Jason R

    Biomechanics (Basel, Switzerland)

    2022  Volume 2, Issue 4, Page(s) 494–499

    Abstract: Much of our current understanding of age-related declines in mobility has been aided by decades of investigations on the role of muscle-tendon units spanning major lower extremity joints (e.g., hip, knee and ankle) for powering locomotion. Yet, ... ...

    Abstract Much of our current understanding of age-related declines in mobility has been aided by decades of investigations on the role of muscle-tendon units spanning major lower extremity joints (e.g., hip, knee and ankle) for powering locomotion. Yet, mechanical contributions from foot structures are often neglected. This is despite the emerging evidence for their critical importance in youthful locomotion. With rapid growth in the field of human foot biomechanics over the last decade, our theoretical knowledge of young asymptomatic feet has transformed, from long-held views of a stiff lever and a shock-absorber to a versatile system that can modulate mechanical power and energy output to accommodate various locomotor task demands. In this perspective review, we predict that the next set of impactful discoveries related to locomotion in older adults will emerge by integrating the novel tools and approaches that are currently transforming the field of human foot biomechanics. By illuminating the functions of feet in older adults, we envision that future investigations will refine our mechanistic understanding of mobility deficits affecting our aging population, which may ultimately inspire targeted interventions to rejuvenate the mechanics and energetics of locomotion.
    Language English
    Publishing date 2022-09-23
    Publishing country Switzerland
    Document type Journal Article
    ISSN 2673-7078
    ISSN (online) 2673-7078
    DOI 10.3390/biomechanics2040038
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Knee Joint Loading during Single-Leg Forward Hopping.

    Krupenevich, Rebecca L / Pruziner, Alison L / Miller, Ross H

    Medicine and science in sports and exercise

    2017  Volume 49, Issue 2, Page(s) 327–332

    Abstract: Increased or abnormal loading on the intact limb is thought to contribute to the relatively high risk of knee osteoarthritis in this limb for individuals with unilateral lower limb loss. This theory has been assessed previously by studying walking, but ... ...

    Abstract Increased or abnormal loading on the intact limb is thought to contribute to the relatively high risk of knee osteoarthritis in this limb for individuals with unilateral lower limb loss. This theory has been assessed previously by studying walking, but knee joint loading during walking is often similar between individuals with and without limb loss, prompting assessment of other movements that may place unusual loads on the knee. One such movement, hopping, is a form of locomotion that individuals with unilateral lower limb loss may situationally use instead of walking, but the mechanical effects of hopping on the intact limb are unknown.
    Purpose: Compare knee joint kinetics of healthy adults during single-leg forward hopping compared to walking, a more traditional form of locomotion.
    Methods: Twenty-four healthy adults walked and hopped at self-selected speeds of 1.5 and 2.3 m·s, respectively. Joint moments were calculated using inverse dynamics. A paired Student's t-test was utilized to compare peak, impulse, and loading rate (LR) of knee adduction moment (KAM), and peak knee flexion moment (KFM) between walking and hopping.
    Results: Peak KFM and KAM LR were greater during hopping compared to walking (peak KFM: 20.73% vs 5.51% body weight (BW) × height (Ht), P < 0.001; KAM LR: 0.47 vs. 0.33 BW·Ht·s, P = 0.01).
    Conclusions: Kinetic measures affecting knee joint loading are greater in hopping compared to walking. It may be advisable to limit single-leg forward hopping in the limb loss population until it is known if these loads increase knee osteoarthritis risk.
    MeSH term(s) Biomechanical Phenomena ; Female ; Humans ; Knee Joint/physiology ; Locomotion/physiology ; Male ; Osteoarthritis, Knee/etiology ; Osteoarthritis, Knee/physiopathology ; Plyometric Exercise ; Risk Factors ; Walking/physiology ; Young Adult
    Language English
    Publishing date 2017-02
    Publishing country United States
    Document type Comparative Study ; Journal Article
    ZDB-ID 603994-7
    ISSN 1530-0315 ; 0195-9131 ; 0025-7990
    ISSN (online) 1530-0315
    ISSN 0195-9131 ; 0025-7990
    DOI 10.1249/MSS.0000000000001098
    Database MEDical Literature Analysis and Retrieval System OnLINE

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