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Introduction:
Advanced age brings a distal-to-proximal redistribution of positive joint work during walking that is relevant to walking performance and economy. It is unclear whether negative joint work is similarly redistributed in old age. Negative work can affect positive work through elastic energy return in gait. We determined the effects of...
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While common characteristics between wearing of high heel between carrying an infant elevate height of center of gravity, it is not known what interaction effect influence to leg stiffness. The aim of the study is to investigate the effect of carrying infant by hip seat carrier on leg me-chanics during high heel gait. Adult female (n=9) and infant...
Citations
... Downhill walking resulted in consistent changes to muscle synergies for both younger and older adults compared to walking on a level slope. For example, when walking downhill there was an increased contribution of vastus lateralis during propulsion (W2), and of vastus medialis in late swing to early stance (W4), suggesting a merging or prolonging of knee extensor activity from weight acceptance (W1) into adjacent synergies when walking downhill, which may be required due to increased eccentric demands placed on the quadriceps (Franz and Kram 2012;Waanders et al. 2019;Santuz et al. 2020). All participants also displayed an increase in the synergy widths of C1 and C3 when walking downhill, whereas the width of C2 was reduced, similar to previous observations (Dewolf et al. 2020). ...
Purpose
The aim of the current study was to determine whether gait control (muscle synergies) or gait stability (margin of stability (MoS)) were different between younger and older adults when walking on level or downhill slopes. Further, it sought to determine associations between either age or physical activity with muscle synergy widths.
Methods
Ten healthy younger (28.1 ± 8.0 years) and ten healthy older (69.5 ± 6.3 years) adults walked at their preferred walking speed on a treadmill at different slopes (0˚, − 4˚ and − 8˚). Muscle synergies were extracted using non-negative matrix factorisation and compared between groups and walking slopes. Correlations between the full width at half maximum (FWHM) of the synergies’ activations and weekly recreational physical activity minutes and age were also determined.
Results
Younger and older adults both walked with similar muscle synergies across all tested slopes, with 4 synergies accounting for > 85% variance of overall muscle activity in both groups across all tested slopes, with high scalar products (≥ 0.86) for each synergy and slope. It was also demonstrated that physical activity and age had different associations with pooled muscle synergies across slopes, as weekly minutes spent in recreational physical activity were associated with the FWHM of a synergy activated at weight acceptance, whereas age was associated with the FWHM of synergies occurring at push off and foot clearance, respectively.
Conclusion
Our results suggest that healthy older and younger adults walk with similar muscle synergies on downhill slopes, and that physical activity and age influence different muscle synergies during walking.
... Task-specific mechanical demand is known to increase with greater body mass, and joint work has been used to quantify differences in lower extremity biomechanics and neuromuscular strategy in obese compared to non-obese adults (12). While absolute joint work is a measure of lower extremity kinetics, relative joint work reflects the contributions of each joint and provides insight to the neuromuscular strategy selected to complete a given task (37). While a number of research studies have investigated the influence of increasing and decreasing body mass on lower extremity biomechanics including joint work and relative joint contributions, these studies have focused on overground or treadmill walking (1,18,30). ...
The purpose of this study was to investigate the influence of simulated changes in body mass on lower extremity joint work and relative joint contributions during stair descent. Ten healthy recreationally active college-age participants performed five stair descent trials in each of five loading conditions: no added load and with an additional 5%, 10%, 15% and 20% of their body weight. Three-dimensional ankle, knee and hip joint powers were calculated using a six degree-of-freedom model in Visual3D (C-Motion Inc., Germantown, MD, USA). Sagittal plane joint work was calculated as the joint power curve integrated with respect to time during the period between initial contact and toe off. Prism 9.0 (GraphPad Inc., San Diego, CA) was used to perform univariate 1 × 5 repeated measures analyses of variance to determine the effect of added mass on absolute and relative joint work values for total and for each lower extremity joint independently. Increasing added mass was associated with greater total lower extremity negative work during the stair descent task (p < 0.001). At the ankle, increasing added mass was associated with increasing magnitudes of negative joint work. Increasing added mass was associated with greater relative contributions of the ankle and reduced knee contributions to total negative lower extremity joint work (p = 0.014 and p = 0.006). The current findings demonstrated increases in ankle joint contributions to total lower extremity work while knee joint contributions to total lower extremity work were reduced in response to increasing added mass.
... Even when not directly suggested, we still can use the information from the studies published in the special issue to raise potential strategies of intervention in old and AD populations based on the studies of Santos et al. 8 Special issue: Effects of aging on locomotor patterns seems to affect the strength of synaptic inputs (inferred by intermuscular beta-coherence) to ankle, but not thigh, muscles during walking 8 , intervention mainly focusing on the ankle muscle seems to be more relevant for older individuals. Indeed, improving ankle functions may be relevant, considering that this can also be beneficial for foot placement (a mechanism of gait stability 23 ) and because of the typical distal-to-proximal redistribution of joint work during walking in older adults 27 . Also, since exercise-induced neuroplasticity is associated with improvements in motor function 28 , enhancing physical activity level may reflect in the strength of synaptic inputs optimizing the motor control, reducing the negative effects on intermuscular beta coherence. ...
Aging and age-associated neurological diseases, such as Alzheimer's disease and Parkinson's disease, may impair walking performance. Changes in walking performance are related to an increase in fall risk, institutionalization, hospitalization, survival rate, and mortality. Due to the increase in the older population, especially age-related diseases, the number of research aiming at understanding the mechanisms behind such changes and tools (interventions) to improve walking performance has increased substantially. In this special issue, we target to compile information and strengthen the discussion about whether and how aging and AD, and PD affect walking (the most common way of human locomotion), and potential interventions to improve walking in these populations. A total of 5 studies composed this special issue, including 4 original papers and 1 review
... These studies have shaped our understanding of how older adults, without the presence of other musculoskeletal pathologies, produce the mechanical power required for locomotion. For example, compared to younger adults, older adults walk with reduced ankle power generation and redistribute the muscular demands to the hip joint [1]a strategy that may be linked to a greater whole-body metabolic energy cost [2], which may potentially accelerate fatigue or reduce walking independence. While these studies are informative, the mechanical contributions of more distal structures in the foot are often neglected. ...
... In our opinion, uncovering the underlying mechanisms of the foot's mechanical energy output across a range of locomotor demands has the potential to refine our understanding of the mobility deficits facing our aging population. For example, understanding foot's energy losses could update the mechanistic knowledge of the characteristic distal-to-proximal redistribution to power locomotion [1] thought to precipitate deleterious effects on the whole-body metabolic energy cost of walking [8]. Additionally, examining how the foot's energy is lost or dissipated across a series of locomotor tasks could provide novel insights into balance control and instability, adding to the current knowledge regarding the link between foot sensation, plantar pressure distribution, and balance control [9]. ...
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 of their critical importance in youthful locomotion. With the 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 the foot as a stiff lever and a shock absorber to that of 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 the 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.
... Differences in joint ME with ageing could be confounded by age-related alterations in speed [9], and step/stride length [3]. To control for such confounders age-related differences in joint ME have been investigated at fixed experimental speeds [6,15]. A limitation of experimentally controlling confounders is that it may reduce the ecological validity of the comparison. ...
Purpose
Understanding what constitutes normal walking mechanics across the adult lifespan is crucial to the identification and intervention of early decline in walking function. Existing research has assumed a simple linear alteration in peak joint powers between young and older adults. The aim of the present study was to quantify the potential (non)linear relationship between age and the joint power waveforms of the lower limb during walking.
Methods
This was a pooled secondary analysis of the authors’ (MT, KD, JJ) and three publicly available datasets, resulting in a dataset of 278 adults between the ages of 19 to 86 years old. Three-dimensional motion capture with synchronised force plate assessment was performed during self-paced walking. Inverse dynamics were used to quantity joint power of the ankle, knee, and hip, which were time-normalized to 100 stride cycle points. Generalized Additive Models for location, scale and shape (GAMLSS) was used to model the effect of cycle points, age, walking speed, stride length, height, and their interaction on the outcome of each joint’s power.
Results
At both 1m/s and 1.5 m/s, A2 peaked at the age of 60 years old with a value of 3.09 (95% confidence interval [CI] 2.95 to 3.23) W/kg and 3.05 (95%CI 2.94 to 3.16), respectively. For H1, joint power peaked with a value of 0.40 (95%CI 0.31 to 0.49) W/kg at 1m/s, and with a value of 0.78 (95%CI 0.72 to 0.84) W/kg at 1.5m/s, at the age of 20 years old. For H3, joint power peaked with a value of 0.69 (95%CI 0.62 to 0.76) W/kg at 1m/s, and with a value of 1.38 (95%CI 1.32 to 1.44) W/kg at 1.5m/s, at the age of 70 years old.
Conclusions
Findings from this study do not support a simple linear relationship between joint power and ageing. A more in-depth understanding of walking mechanics across the lifespan may provide more opportunities to develop early clinical diagnostic and therapeutic strategies for impaired walking function. We anticipate that the present methodology of pooling data across multiple studies, is a novel and useful research method to understand motor development across the lifespan.
... To improve accuracy, most studies leverage anthropometric scaling factors, meaning muscle-tendon parameters are adjusted based on a subject's height and/or weight [10,11]. However, anthropometric scaling does not capture known parameter variation due to age [12,13], sex [14], physical training [15], or muscle function [16]. To overcome this limitation, others have employed medical imaging technologies, such as magnetic resonance imaging and ultrasound, to estimate Hill-type parameters [17]. ...
Objective
Hill-type muscle models are widely employed in simulations of human movement. Yet, the parameters underlying these models are difficult or impossible to measure in vivo. Prior studies demonstrate that Hill-type muscle parameters are encoded within dynamometric data. But, a generalizable approach for estimating these parameters from dynamometric data has not been realized. We aimed to leverage musculoskeletal models and artificial neural networks to classify one Hill-type muscle parameter (maximum isometric force) from easily measurable dynamometric data (simulated lateral pinch force). We tested two neural networks (feedforward and long short-term memory) to identify if accounting for dynamic behavior improved accuracy.
Methods
We generated four datasets via forward dynamics, each with increasing complexity from adjustments to more muscles. Simulations were grouped and evaluated to show how varying the maximum isometric force of thumb muscles affects lateral pinch force. Both neural networks classified these groups from lateral pinch force alone.
Results
Both neural networks achieved accuracies above 80% for datasets which varied only the flexor pollicis longus and/or the abductor pollicis longus. The inclusion of muscles with redundant functions dropped model accuracies to below 30%. While both neural networks were consistently more accurate than random guess, the long short-term memory model was not consistently more accurate than the feedforward model.
Conclusion
Our investigations demonstrate that artificial neural networks provide an inexpensive, data-driven approach for approximating Hill-type muscle-tendon parameters from easily measurable data. However, muscles of redundant function or of little impact to force production make parameter classification more challenging.
... This is the first study about gait kinetics in older people with MCI and SCD; therefore, negative findings may indicate that mild cognitive decline may not have a big impact on gait kinetics during level walking. Gait speed can influence joint moments and a stronger muscle contraction is required to produce high joint moments; therefore, older adults are less capable to produce a higher peak ankle moment when facing a higher task demand (Waanders et al., 2019). In this study, we chose self-selected walking speed during gait analysis, which might not be very challenging. ...
... In addition, obesity and high BMI have also been found to have a significant influence on gait kinematics, causing a large hip joint angle in both sagittal and transverse planes (Rosso et al., 2019) and a smaller hip ROM (Agostini et al., 2017). In addition, different walking speeds significantly influence gait kinetics (Waanders et al., 2019). Furthermore, diabetes mellitus (DM) was reported to have a potential influence on gait parameters simultaneously (Kimura et al., 2018). ...
Background
Older adults with mild cognitive impairment (MCI) have slower gait speed and poor gait performance under dual-task conditions. However, gait kinematic and kinetic characteristics in older adults with MCI or subjective cognitive decline (SCD) remain unknown. This study was designed to explore the difference in gait kinematics and kinetics during level walking among older people with MCI, SCD, and normal cognition (NC).
Methods
This cross-sectional study recruited 181 participants from July to December 2019; only 82 met the inclusion criteria and consented to participate and only 79 completed gait analysis. Kinematic and kinetic data were obtained using three-dimensional motion capture system during level walking, and joint movements of the lower limbs in the sagittal plane were analyzed by Visual 3D software. Differences in gait kinematics and kinetics among the groups were analyzed using multivariate analysis of covariance (MANCOVA) with Bonferroni post-hoc analysis. After adjusting for multiple comparisons, the significance level was p < 0.002 for MANCOVA and p < 0.0008 for post-hoc analysis.
Results
Twenty-two participants were MCI [mean ± standard deviation (SD) age, 71.23 ± 6.65 years], 33 were SCD (age, 72.73 ± 5.25 years), and 24 were NC (age, 71.96 ± 5.30 years). MANCOVA adjusted for age, gender, body mass index (BMI), gait speed, years of education, diabetes mellitus, and Geriatric Depression Scale (GDS) revealed a significant multivariate effect of group in knee peak extension angle ( F = 8.77, p < 0.0001) and knee heel strike angle ( F = 8.07, p = 0.001) on the right side. Post-hoc comparisons with Bonferroni correction showed a significant increase of 5.91° in knee peak extension angle ( p < 0.0001) and a noticeable decrease of 6.21°in knee heel strike angle ( p = 0.001) in MCI compared with NC on the right side. However, no significant intergroup difference was found in gait kinetics, including dorsiflexion, plantar flexion, knee flexion, knee extension, hip flexion, and hip extension( p > 0.002).
Conclusion
An increase of right knee peak extension angle and a decrease of right knee heel strike angle during level walking were found among older adults with MCI compared to those with NC.
... 7,8 This compensatory mechanism is well-known as distal-to-proximal redistribution of positive joint work and power within the lower limb to generate propulsive power during walking. 9,10 Previously, using a double inverted pendulum model, it was found that during walking, lower push-off forces at the ground contact point of the trailing leg and higher compensatory hip extensor moments at the leading leg increased the energy dissipation when redirecting the center of mass velocity. 11 This might partly explain why the proximal shift in joint moments would be related to higher whole-body energy cost of walking in older adults. ...
... Larger total positive work at the ankle was found in young adults at slow and fast speeds. Inversely, larger total positive work at the hip was found in older adults at both speeds studies regarding the "biomechanical plasticity/elasticity" of older adult's gait patterns 8,10,23,50 and highlights the key role of the hip to compensate for the decreased ability of older adults to use their ankle musculature during walking. Although experimental evidence is lacking, it has previously been suggested that the hip muscles (long fibers and short tendons with little elastic energy storing capacity) generate muscle forces during walking less efficiently than the triceps surae muscles (short fibers and long tendons with higher elastic energy storing capacity). ...
Age-related neural and musculoskeletal declines affect mobility and the quality of life of older adults. To date, the mechanisms underlying reduced walking economy in older adults still remain elusive. In this study, we wanted to investigate which biomechanical factors were associated with the higher energy cost of walking in older compared to young adults. Fourteen older (24 ± 2 years) and fourteen young (74 ± 4 years) adults were tested. Plantarflexor strength and Achilles tendon stiffness were evaluated during a dynamometer test. Medial gastrocnemius fascicle length, ground reaction forces, joint kinematics and oxygen consumption were measured during walking treadmill at 0.83 m.s-1 and 1.39 m.s-1 . Energy cost of walking, lower-limb joint mechanics, muscle-tendon unit and tendinous tissues length were calculated. The energy cost of walking was higher at 0.83 m.s-1 (+16%; p = 0.005) and plantarflexor strength lower (-31%; p = 0.007) in older adults. Achilles tendon stiffness and medial gastrocnemius fascicle length changes did not differ between older and young adults. The reduction in ankle mechanics was compensated by increases in hip mechanics in older adults during walking. The hip extensor moment was the only significant predictor of the energy cost of walking (adjusted R2 : 0.35-0.38). The higher energy cost in older adults is mainly associated with their distal-to-proximal redistribution of joint mechanics during walking possibly due to plantarflexor weakness. In our study, medial gastrocnemius fascicle and tendinous tissue behavior did not explain the higher energy cost of walking in older compared to young adults.
... 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. ...
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.
... These power phases represent the positive power generation by lower extremity extensor muscles during the stance phase. Joint power analysis was limited to positive power phases only because Waanders, Hortobagyi, Murgia, Devita, and Franz (2019), recently showed that aging primarily affects redistribution of positive and not negative joint powers. ...
... The older and young participants showed similar systematic increases in ankle, knee, and hip joint extensor moments with increases in step length. Age-related decline in push-off kinetics (i.e., reduced ankle moment and power in A2 phase) is a robust finding supported extensively in the literature on redistribution of net joint moments, impulses, powers, and work (Buddhadev & Martin, 2016;Cofre et al., 2011;DeVita & Hortobagyi, 2000;Hortobagyi et al., 2016;Kuhman et al., 2018;Monaco et al., 2009;Silder et al., 2008;Waanders et al., 2019). In the current study, we performed two unique manipulations (i.e., speed vs. step length) to increase the difficulty of walking. ...
During walking older adults' gait is slower, they take shorter steps, and rely less on ankle and more on knee and hip joint moments and powers compared to young adults. Previous studies have suggested that walking speed and step length are confounds that affect joint moments and powers. Our purpose was to examine the effects of walking speed and step length manipulation on net joint moments and powers in young and older adults. Sixteen young and 18 older adults completed walking trials at three speeds under three step length conditions as marker position and force platform data were captured synchronously. Net joint moments were quantified using inverse dynamics and were subsequently used to compute net joint powers. Average extensor moments at each joint during the stance phase were then computed. Older adults displayed greater knee extensor moment compared to young adults. Older adults showed trends (p < .10) of having lower ankle and higher hip moments, but these differences were not statistically significant. Average ankle, knee, and hip extensor moments increased with speed and step length. At the fast speed, older compared to young adults generated lower average ankle power (p = .003) and showed a trend (p = .056) of exerting less average moment at the ankle joint. Age-associated distal-to-proximal redistribution of net joint moments was diminished and not statistically significant when the confounding effects of walking speed and relative step length were controlled. These findings imply that age-related distal-to-proximal redistribution of joint moments may influence the different speeds and step lengths chosen by young and older adults.
