30 results on '"Hoogkamer, Wouter"'
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2. Longitudinal bending stiffness does not affect running economy in Nike Vaporfly Shoes
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Healey, Laura A. and Hoogkamer, Wouter
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- 2022
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3. Assessing the validity of the zero-velocity update method for sprinting speeds.
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Aristizábal Pla, Gerard, Martini, Douglas N., Potter, Michael V., and Hoogkamer, Wouter
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SPRINTING ,FOOTWEAR ,KINEMATICS - Abstract
The zero-velocity update (ZUPT) method has become a popular approach to estimate foot kinematics from foot worn inertial measurement units (IMUs) during walking and running. However, the accuracy of the ZUPT method for stride parameters at sprinting speeds remains unknown, specifically when using sensors with characteristics well suited for sprinting (i.e., high accelerometer and gyroscope ranges and sampling rates). Seventeen participants performed 80-meter track sprints while wearing a Blue Trident IMeasureU IMU. Two cameras, at 20 and 70 meters from the start, were used to validate the ZUPT method on a stride-by-stride and on a cumulative distance basis. In particular, the validity of the ZUPT method was assessed for: (1) estimating a single stride length attained near the end of an 80m sprint (i.e., stride at 70m); (2) estimating cumulative distance from ∼20 to ∼70 m; and (3) estimating total distance traveled for an 80-meter track sprint. Individual stride length errors at the 70-meter mark were within -6% to 3%, with a bias of -0.27%. Cumulative distance errors were within -4 to 2%, with biases ranging from -0.85 to -1.22%. The results of this study demonstrate the ZUPT method provides accurate estimates of stride length and cumulative distance traveled for sprinting speeds. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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4. Measuring Mechanical and Metabolic Power during Uphill Treadmill Cycling: 1383 Board #58 June 1 9: 00 AM - 10: 30 AM
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Straw, Asher H., Frank, Jesse H., Pham, Bryant T., Carver, Todd M., and Hoogkamer, Wouter
- Published
- 2017
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5. Front Suspension Does Not Increase Mechanical or Metabolic Power Requirements during Uphill Bicycling: 1379 Board #54 June 1 9: 00 AM - 10: 30 AM
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Carver, Todd M., Straw, Asher H., Frank, Jesse H., Kraus, Tyler S., and Hoogkamer, Wouter
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- 2017
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6. Perception of Gait Asymmetry During Split-Belt Walking
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Hoogkamer, Wouter
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- 2017
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7. Altered Running Economy Directly Translates to Altered Distance-Running Performance
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HOOGKAMER, WOUTER, KIPP, SHALAYA, SPIERING, BARRY A., and KRAM, RODGER
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- 2016
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8. The metabolic cost of emulated aerodynamic drag forces in marathon running.
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da Silva, Edson Soares, Kram, Rodger, and Hoogkamer, Wouter
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DRAG (Aerodynamics) ,AERODYNAMIC load ,DRAG force ,MARATHON running ,DRAG reduction - Abstract
The benefits of drafting for elite marathon runners are intuitive, but the quantitative energetic and time savings are still unclear due to the different methods used for converting aerodynamic drag force reductions to gross metabolic power savings. Further, we lack a mechanistic understanding of the relationship between aerodynamic drag forces and ground reaction forces (GRFs) over a range of running velocities. Here, we quantified how small horizontal impeding forces affect gross metabolic power and GRF over a range of velocities in competitive runners. In three sessions, 12 runners completed six 5-min trials with 5 min of recovery in-between. We tested one velocity per session (12, 14, and 16 km/h), at three horizontal impeding force conditions (0, 4, and 8 N) applied at the waist of the runners. On average, gross metabolic power increased by 6.13% per 1% body weight of horizontal impeding force but the increases varied considerably between individuals (4.17%-8.14%). With greater horizontal impeding force, braking GRF impulses decreased, whereas propulsive GRF impulses increased, but the impulses were not related to individual changes in gross metabolic power. Combining our findings with those of previous aerodynamics studies, we estimate that for a solo runner (52 kg) at 2-h marathon pace, overcoming aerodynamic drag force (1.39% BW) comprises 7.8% of their gross metabolic power and drafting can save between 3 min 42 s and 5 min 29 s. NEW & NOTEWORTHY We measured the metabolic and biomechanical effects of small horizontal impeding forces (representing realistic aerodynamic drag forces) on high-caliber runners across a range of velocities. Combining our metabolic results with existing aerodynamic models indicates that at 2-h marathon pace, optimal drafting likely allows a marathoner to run between 3 min 42 s and 5 min 29 s faster. Our rule-of-thumb (~6% increase in gross metabolic power per 1% body weight of horizontal impeding force) will allow others to estimate the performance enhancement of different drafting formations. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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9. Changing Stride Frequency Alters Average Joint Power and Power Distributions during Ground Contact and Leg Swing in Running.
- Author
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SWINNEN, WANNES, MYLLE, INE, HOOGKAMER, WOUTER, DE GROOTE, FRIEDL, and VANWANSEELE, BENEDICTE
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- 2021
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10. Different neural substrates for precision stepping and fast online step adjustments in youth : Neural correlates of precision stepping in youth
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Corporaal, Sharissa, Bruijn, Sjoerd, Hoogkamer, Wouter, Chalavi, Sima, Boisgontier, Matthieu, Duysens, Jaak, Swinnen, Stephan, and Gooijers, Jolien
- Abstract
Humans can navigate through challenging environments (e.g., cluttered or uneven terrains) by modifying their preferred gait pattern (e.g., step length, step width, or speed). Growing behavioral and neuroimaging evidence suggests that the ability to modify preferred step patterns requires the recruitment of cognitive resources. In children, it is argued that prolonged development of complex gait is related to the ongoing development of involved brain regions, but this has not been directly investigated yet. Here, we aimed to elucidate the relationship between structural brain properties and complex gait in youth aged 9 - 18 years. We used volumetric analyses of cortical grey matter (GM) and whole brain voxel-wise statistical analyses of cortical white matter (WM), and utilized a treadmill-based precision stepping task to investigate complex gait. Moreover, precision stepping was performed on step targets which were either unperturbed or perturbed (i.e., unexpectedly shifting to a new location). Our main findings revealed that larger unperturbed precision step error was associated with decreased WM microstructural organization of tracts that are particularly associated with attentional and visual processing functions. These results strengthen the hypothesis that precision stepping on unperturbed step targets is driven by cortical processes. In contrast, no significant correlations were found between perturbed precision stepping and cortical structures, indicating that other (neural) mechanisms may be more important for this type of stepping. ispartof: Brain Structure and Function vol:223 issue:4 pages:2039-2053 ispartof: location:Germany status: published
- Published
- 2018
11. Neural Control of Walking: Role of the Cerebellum : Neurale Sturing van het Wandelen: de Rol van het Cerebellum
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Hoogkamer, Wouter, Van Calenbergh, Frank, Sunaert, Stefan, and Duysens, Jaak
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human activities - Abstract
Walking is a relatively easy task; we can walk without thinking about how to do it. While we are able to walk without thinking about it, from a control perspective, walking is definitely not a simple task. It needs to be stable and efficient in a broad range of different conditions. Insights into the neural control of gait are important to learn us about why specific individuals (patients, elderly) experience difficulties with walking, in general or under specific conditions. With this knowledge rehabilitation and fall prevention strategies can be optimized.While it is known that there is an important role for the spinal circuitry in the neural control of gait, multiple supraspinal structures have been suggested to contribute substantially as well. Specifically, based on common gait deficits in cerebellar patients, the cerebellum can be expected to be important in the neural control of gait. So far this has been evaluated in humans, mainly during unperturbed, steady state walking. An important next step is to study the role of the cerebellum in the control of gait corrections in reaction to perturbations. In those conditions, the cerebellum can be expected to be even more involved in the control of gait, because of its function in comparing expected and real sensory signals.The objective of this thesis was to increase the understanding of the roles of the cerebellum in the control of gait corrections in reaction to perturbations, and of the localization of these functions within the cerebellum. We evaluated the role of the cerebellum in dynamic gait stability, in cutaneous reflex modulation during gait and in locomotor adaptation, all important features of neural control of gait in non-steady state conditions.In the first part, we performed three studies, focusing on the relationship between cutaneous reflex modulation and gait stability, and on the role of the cerebellum in these features. First, we studied cutaneous reflexes during backward walking in healthy controls and observed a prominent phase-dependent reflex modulation during this task. Next, we addressed the potential role of the cerebellum in the control of cutaneous reflexes. Cutaneous reflex modulation was similar between healthy controls and patients with focal cerebellar lesions, but the latter appeared less able to attenuate reflexes to self-induced stimuli. This suggests that the cerebellum is not primarily involved in cutaneous reflex modulation but that it could act in attenuation of self-induced reflex responses. The latter role in locomotion would be consistent with the common view that the cerebellum predicts sensory consequences of movement. Furthermore, biceps femoris muscle activity during the single stance phases was increased in the patient group compared to the controls. This increased activation was likely related to a co-activation strategy to reduce instability of gait. This was supported by findings in our third study, where we evaluated dynamic gait stability in patients with focal cerebellar lesions and in healthy controls. The short-term maximum Lyapunov exponent was higher in cerebellar patients, indicating reduced dynamic gait stability. Furthermore, while step width was increased and self-selected overground walking speed was decreased in the patient group while other spatio-temporal gait parameters were similar. Patients with the largest lesions in the vermis displayed the least stable gait pattern.In the second part, we focused on split-belt walking which, in the past decade, has become a popular paradigm to study the role of the cerebellum in locomotor adaptation. First, we evaluated split-belt adaptation in healthy controls and mildly ataxic patients with focal cerebellar lesions. We observed that during the split-belt adaptation experiment, patients and healthy controls globally displayed similar changes in gait parameters. However, a group difference was observed in the aftereffect of the Stance Time Symmetry: during the early phase of the post-adaptation period the relative stance times were more asymmetric for the patient group than for the control group. Patients who walked with more asymmetric relative stance times were more likely to have lesions in vermal lobules VI and Crus II. In the final study, we assessed the role of somatosensory perception in the control of split-belt walking. We observed that participants who were less able to perceive differences between belt speeds, initially walked with more asymmetric stance times during split-belt walking. This is in line with our general view that load and stretch information are important in the neural control of gait.In conclusion, the cerebellum appears important in the control in dynamic gait stability. Furthermore, our data suggests that the cerebellum is not primarily involved in cutaneous reflex modulation but that it could act in attenuation of self-induced reflex responses. Our results demonstrated that mildly ataxic cerebellar patients show no deficits in split-belt adaptation but exhibit differences in the post-adaptation period. Finally, the observed relations between speed-difference perception and gait asymmetry during split-belt walking confirmed the importance of proprioceptive information in gait control.
- Published
- 2014
12. Effect of habitual foot-strike pattern on the gastrocnemius medialis muscletendon interaction and muscle force production during running.
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Swinnen, Wannes, Hoogkamer, Wouter, Delabastita, Tijs, Aeles, Jeroen, De Groote, Friedl, and Vanwanseele, Benedicte
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FLEXOR muscles ,MUSCLES - Abstract
The interaction between gastrocnemius medialis (GM) muscle and Achilles tendon, i.e., muscle-tendon unit (MTU) interaction, plays an important role in minimizing the metabolic cost of running. Footstrike pattern (FSP) has been suggested to alter MTU interaction and subsequently the metabolic cost of running. However, metabolic data from experimental studies on FSP are inconsistent, and a comparison of MTU interaction between FSP is still lacking. We, therefore, investigated the effect of habitual rearfoot and mid-/forefoot striking on MTU interaction, ankle joint work, and plantar flexor muscle force production while running at 10 and 14 km/h. GM muscle fascicles of 9 rearfoot and 10 mid-/forefoot strikers were tracked using dynamic ultrasonography during treadmill running. We collected kinetic and kinematic data and used musculoskeletal models to determine joint angles and calculate MTU lengths. In addition, we used dynamic optimization to assess plantar flexor muscle forces. During ground contact, GM fascicle shortening (P = 0.02) and average contraction velocity (P = 0.01) were 40-45% greater in rearfoot strikers than mid-/forefoot strikers. Differences in contraction velocity were especially prominent during early ground contact. Moreover, GM (P = 0.02) muscle force was greater during early ground contact in mid-/ forefoot strikers than rearfoot strikers. Interestingly, we did not find differences in stretch or recoil of the series elastic element between FSP. Our results suggest that, for the GM, the reduced muscle energy cost associated with lower fascicle contraction velocity in mid-/ forefoot strikers may be counteracted by greater muscle forces during early ground contact. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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13. Extrapolating Metabolic Savings in Running: Implications for Performance Predictions.
- Author
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Kipp, Shalaya, Kram, Rodger, and Hoogkamer, Wouter
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LOCOMOTION ,MARATHON running ,VELOCITY ,AIR resistance ,AEROBIC capacity - Abstract
Training, footwear, nutrition, and racing strategies (i.e., drafting) have all been shown to reduce the metabolic cost of distance running (i.e., improve running economy). However, how these improvements in running economy (RE) quantitatively translate into faster running performance is less established. Here, we quantify how metabolic savings translate into faster running performance, considering both the inherent rate of oxygen uptake-velocity relation and the additional cost of overcoming air resistance when running overground. We collate and compare five existing equations for oxygen uptake-velocity relations across wide velocity ranges. Because the oxygen uptake vs. velocity relation is non-linear, for velocities slower than ∼3 m/s, the predicted percent improvement in velocity is slightly greater than the percent improvement in RE. For velocities faster than ∼3 m/s, the predicted percent improvement in velocity is less than the percent improvements in RE. At 5.5 m/s, i.e., world-class marathon pace, the predicted percent improvement in velocity is ∼2/3rds of the percent improvement in RE. For example, at 2:04 marathon pace, a 3% improvement in RE translates to a 1.97% faster velocity or 2:01:36, almost exactly equal to the recently set world record. [ABSTRACT FROM AUTHOR]
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- 2019
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14. Response inhibition during avoidance of virtual obstacles
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Potocanac, Zrinka, Smulders, Ellen, Hoogkamer, Wouter, Pijnappels, Mirjam, Verschueren, Sabine, and Duysens, Jaak
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While walking, one often has to suppress and adjust a planned step in order to avoid a fall. Given that steps are preprogrammed this requires some form of motor inhibition. Motor inhibition is commonly tested in hand function and only recently attempts have been made to evaluate inhibition in the lower limbs, during step initiation. As adequate motor inhibition might play a role in avoiding falls a test to assess response inhibition during walking would be valuable. We developed a task in which subjects walked on a treadmill by stepping on projected patches of light, which could suddenly change color forcing the subjects to avoid it by shortening or lengthening their steps. The difficulty level was manipulated in 4 conditions by changing the distance available to respond. We hypothesized that larger demands on motor inhibition during walking would produce more failures and tested the performance of young adults (n=12) in order to establish the protocol for use in older adults. The failure rate on the walking test was analyzed. Reducing the available response distance by 150 mm from the easiest condition resulted in a significant increase in failure rates from 15.6% to 65.1%. Therefore, results indicate this novel test can be used to assess the level of motor inhibition during walking. Additionally, in comparison to previous literature on obstacle avoidance, our experiment shows that changing a precise aiming movement is considerably more challenging than changing the same movement executed automatically. publisher: Elsevier articletitle: Response inhibition during avoidance of virtual obstacles while walking journaltitle: Gait & Posture articlelink: http://dx.doi.org/10.1016/j.gaitpost.2013.07.125 content_type: article copyright: Copyright © 2013 Elsevier B.V. All rights reserved. ispartof: GAIT & POSTURE vol:39 issue:1 pages:641-644 ispartof: location:Leuven status: published
- Published
- 2013
15. Predictability Of Indoor Track And Cross Country Performances Using D' Or Anaerobic Work Capacity: 115.
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Hutchison, Randolph E., Biddle, Sara, Hoogkamer, Wouter, Thomas, Shernice, Arellano, Christopher J., Leggat, Caitlyn, Lalonde, James, and Abrahamson, Georgie
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- 2022
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16. Regional Volumes in Brain Stem and Cerebellum Are Associated With Postural Impairments in Young Brain-Injured Patients.
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Drijkoningen, David, Leunissen, Inge, Caeyenberghs, Karen, Hoogkamer, Wouter, Sunaert, Stefan, Duysens, Jacques, and Swinnen, Stephan P
- Abstract
Many patients with traumatic brain injury (TBI) suffer from postural control impairments that can profoundly affect daily life. The cerebellum and brain stem are crucial for the neural control of posture and have been shown to be vulnerable to primary and secondary structural consequences of TBI. The aim of this study was to investigate whether morphometric differences in the brain stem and cerebellum can account for impairments in static and dynamic postural control in TBI. TBI patients (n = 18) and healthy controls (n = 30) completed three challenging postural control tasks on the EquiTest® system (Neurocom). Infratentorial grey matter (GM) and white matter (WM) volumes were analyzed with cerebellum-optimized voxel-based morphometry using the spatially unbiased infratentorial toolbox. Volume loss in TBI patients was revealed in global cerebellar GM, global infratentorial WM, middle cerebellar peduncles, pons and midbrain. In the TBI group and across both groups, lower postural control performance was associated with reduced GM volume in the vermal/paravermal regions of lobules I-IV, V and VI. Moreover, across all participants, worse postural control performance was associated with lower WM volume in the pons, medulla, midbrain, superior and middle cerebellar peduncles and cerebellum. This is the first study in TBI patients to demonstrate an association between postural impairments and reduced volume in specific infratentorial brain areas. Volumetric measures of the brain stem and cerebellum may be valuable prognostic markers of the chronic neural pathology, which complicates rehabilitation of postural control in TBI. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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17. Adaptation and aftereffects of split-belt walking in cerebellar lesion patients.
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Hoogkamer, Wouter, Bruijn, Sjoerd M., Sunaert, Stefan, Swinnen, Stephan P., Van Calenbergh, Frank, and Duysens, Jacques
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To walk efficiently and stably on different surfaces under various constrained conditions, humans need to adapt their gait pattern substantially. Although the mechanisms behind locomotor adaptation are still not fully understood, the cerebellum is thought to play an important role. In this study we aimed to address the specific localization of cerebellar involvement in split-belt adaptation by comparing performance in patients with stable focal lesions after cerebellar tumor resection and in healthy controls. We observed that changes in symmetry of those parameters that were most closely related to interlimb coordination (such as step length and relative double stance time) were similar between healthy controls and cerebellar patients during and after split-belt walking. In contrast, relative stance times (proportions of stance in the gait cycle) were more asymmetric for the patient group than for the control group during the early phase of the post-split-belt condition. Patients who walked with more asymmetric relative stance times were more likely to demonstrate lesions in vermal lobules VI and Crus II. These results confirm that deficits in gait adaptation vary with ataxia severity and between patients with different types of cerebellar damage. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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18. Gait asymmetry during early split-belt walking is related to perception of belt speed difference.
- Author
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Hoogkamer, Wouter, Bruijn, Sjoerd M., Potocanac, Zrinka, Van Calenbergh, Frank, Swinnen, Stephan P., and Duysens, Jacques
- Abstract
Gait adaptation is essential for humans to walk according to the different demands of the environment. Although locomotor adaptation has been studied in different contexts and in various patient populations, the mechanisms behind locomotor adaptation are still not fully understood. The aim of the present study was to test two opposing hypotheses about the control of split-belt walking, one based on avoidance of limping and the other on avoiding limb excursion asymmetry. We assessed how well cerebellar patients with focal lesions and healthy control participants could sense differences between belt speeds during split-belt treadmill walking and correlated this to split-belt adaptation parameters. The ability to perceive differences between belt speeds was similar between the cerebellar patients and the healthy controls. After combining all participants, we observed a significant inverse correlation between stance time symmetry and limb excursion symmetry during the early phase of split-belt walking. Participants who were better able to perceive belt speed differences (e.g., they had a lower threshold and hence were able to detect a smaller speed difference) walked with the smallest asymmetry in stance time and the largest asymmetry in limb excursion. Our data support the hypothesis that humans aim to minimize (temporal) limping rather than (spatial) limb excursion asymmetry when using their perception of belt speed differences in the early phase of adaptation to split-belt walking. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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19. Cutaneous reflex modulation and self-induced reflex attenuation in cerebellar patients.
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Hoogkamer, Wouter, Van Calenbergh, Frank, Swinnen, Stephan P., and Duysens, Jacques
- Subjects
- *
CEREBELLAR ataxia , *NEURAL pathways , *WALKING , *HUMAN locomotion , *NEUROPHYSIOLOGY , *PATIENTS - Abstract
Modulation of cutaneous reflexes is important in the neural control of walking, yet knowledge about underlying neural pathways is still incomplete. Recent studies have suggested that the cerebellum is involved. Here we evaluated the possible roles of the cerebellum in cutaneous reflex modulation and in attenuation of self-induced reflexes. First we checked whether leg muscle activity during walking was similar in patients with focal cerebellar lesions and in healthy control subjects. We then recorded cutaneous reflex activity in leg muscles during walking. Additionally, we compared reflexes after standard (computer triggered) stimuli with reflexes after self-induced stimuli for both groups. Biceps femoris and gastrocnemius medialis muscle activity was increased in the patient group compared with the control subjects, suggesting a coactivation strategy to reduce instability of gait. Cutaneous reflex modulation was similar between healthy control subjects and cerebellar patients, but the latter appeared less able to attenuate reflexes to self-induced stimuli. This suggests that the cerebellum is not primarily involved in cutaneous reflex modulation but that it could act in attenuation of self-induced reflex responses. The latter role in locomotion would be consistent with the common view that the cerebellum predicts sensory consequences of movement. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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20. Sensorimotor recalibration during split-belt walking: task-specific and multisensory?
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Hoogkamer, Wouter and O'Brien, Megan K.
- Subjects
- *
SENSORIMOTOR cortex , *CALIBRATION , *MOTOR cortex , *PHYSIOLOGICAL adaptation , *MOTION perception (Vision) - Abstract
Motor adaptations not only recalibrate movement execution but also can lead to altered movement perception in multiple sensory domains. Vazquez, Statton, Busgang, and Bastian (J Neurophysiol 114: 3255-3267, 2015) recently showed that splitbelt walking affects perception of leg speed during walking, but not perceptions of leg position during standing and walking or perception of contact force during stepping. Considering their findings within the broader scope of sensorimotor recalibration in other tasks, we suggest that sensorimotor recalibrations are task specific and can be multisensory. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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21. Steps Forward in Understanding Backward Gait: From Basic Circuits to Rehabilitation.
- Author
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Hoogkamer, Wouter, Meyns, Pieter, and Duysens, Jacques
- Abstract
Backward locomotion is used increasingly in sports and rehabilitation. However, it is unclear whether training effects of backward walking (BW)/backward running (BR) can be transferred simply to forward walking (FW)/forward running (FR). This touches on the question whether the same neural substrate can generate FW and BW. The available evidence suggests that BW uses the same rhythm circuitry but additionally requires specialized control circuits. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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22. Selective bilateral activation of leg muscles after cutaneous nerve stimulation during backward walking.
- Author
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Hoogkamer, Wouter, Massaad, Firas, Jansen, Karen, Bruijn, Sjoerd M., and Duysens, Jacques
- Abstract
During human locomotion, cutaneous reflexes have been suggested to function to preserve balance. Specifically, cutaneous reflexes in the contralateral leg's muscles (with respect to the stimulus) were suggested to play an important role in maintaining stability during locomotor tasks where stability is threatened. We used backward walking (BW) as a paradigm to induce unstable gait and analyzed the cutaneous reflex activity in both ipsilateral and contralateral lower limb muscles after stimulation of the sural nerve at different phases of the gait cycle. In BW, the tibialis anterior (TA) reflex activity in the contralateral leg was markedly higher than TA background EMG activity during its stance phase. In addition, in BW a substantial reflex suppression was observed in the ipsilateral biceps femoris during the stance-swing transition in some participants, while for medial gastrocnemius the reflex activity was equal to background activity in both legs. To test whether the pronounced crossed responses in TA could be related to instability, the responses were correlated with measures of stability (short-term maximum Lyapunov exponents and step width). These measures were higher for BW compared with forward walking, indicating that BW is less stable. However, there was no significant correlation between these measures and the amplitude of the crossed TA responses in BW. It is therefore proposed that these crossed responses are related to an attempt to briefly slow down (TA decelerates the center of mass in the single-stance period) in the light of unexpected perturbations, such as provided by the sural nerve stimulation. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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23. Is Action-Perception Coupling Improved with Delay in Patients with Focal Cerebellar Lesions?
- Author
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Hoogkamer, Wouter and Meyns, Pieter
- Subjects
- *
CEREBELLUM , *SENSORY perception , *TISSUE wounds , *EYE movement disorders - Abstract
The article presents the study regarding the role of the cerebellum in action?perception coupling by the scientist A. Christensen, and colleagues published in the periodical "Journal of Neuroscience". It presents that Christensen studied patients with focal cerebellar lesions in a paradigm that measures motor execution effect on visual action perception. It mentions the experiments performed by Christensen where factors, such as oculomotor deficits in the patient, were taken into account.
- Published
- 2014
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24. Gait Adaptation to Asymmetric Hip Stiffness Applied by a Robotic Exoskeleton.
- Author
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Abdikadirova B, Price M, Jaramillo JM, Hoogkamer W, and Huber ME
- Subjects
- Humans, Gait, Walking, Lower Extremity, Exercise Test, Biomechanical Phenomena, Adaptation, Physiological, Exoskeleton Device
- Abstract
Wearable exoskeletons show significant potential for improving gait impairments, such as interlimb asymmetry. However, a more profound understanding of whether exoskeletons are capable of eliciting neural adaptation is needed. This study aimed to characterize how individuals adapt to bilateral asymmetric joint stiffness applied by a hip exoskeleton, similar to split-belt treadmill training. Thirteen unimpaired individuals performed a walking trial on the treadmill while wearing the exoskeleton. The right side of the exoskeleton acted as a positive stiffness torsional spring, pulling the thigh towards the neutral standing position, while the left acted as a negative stiffness spring pulling the thigh away from the neutral standing position. The results showed that this intervention applied by a hip exoskeleton elicited adaptation in spatiotemporal and kinetic gait measures similar to split-belt treadmill training. These results demonstrate the potential of the proposed intervention for retraining symmetric gait.
- Published
- 2024
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25. Minimum effort simulations of split-belt treadmill walking exploit asymmetry to reduce metabolic energy expenditure.
- Author
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Price M, Huber ME, and Hoogkamer W
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- Humans, Exercise Test, Energy Metabolism, Adaptation, Physiological physiology, Biomechanical Phenomena, Walking physiology, Gait physiology
- Abstract
Walking on a split-belt treadmill elicits an adaptation response that changes baseline step length asymmetry. The underlying causes of this adaptation, however, are difficult to determine. It has been proposed that effort minimization may drive this adaptation, based on the idea that adopting longer steps on the fast belt, or positive step length asymmetry (SLA), can cause the treadmill to exert net-positive mechanical work on a bipedal walker. However, humans walking on split-belt treadmills have not been observed to reproduce this behavior when allowed to freely adapt. To determine if an effort-minimization motor control strategy would result in experimentally observed adaptation patterns, we conducted simulations of walking on different combinations of belt speeds with a human musculoskeletal model that minimized muscle excitations and metabolic rate. The model adopted increasing amounts of positive SLA and decreased its net metabolic rate with increasing belt speed difference, reaching +42.4% SLA and -5.7% metabolic rate relative to tied-belt walking at our maximum belt speed ratio of 3:1. These gains were primarily enabled by an increase in braking work and a reduction in propulsion work on the fast belt. The results suggest that a purely effort minimization driven split-belt walking strategy would involve substantial positive SLA, and that the lack of this characteristic in human behavior points to additional factors influencing the motor control strategy, such as aversion to excessive joint loads, asymmetry, or instability. NEW & NOTEWORTHY Behavioral observations of split-belt treadmill adaptation have been inconclusive toward its underlying causes. To estimate gait patterns when driven exclusively by one of these possible underlying causes, we simulated split-belt treadmill walking with a musculoskeletal model that minimized its summed muscle excitations. Our model took significantly longer steps on the fast belt and reduced its metabolic rate below tied-belt walking, unlike experimental observations. This suggests that asymmetry is energetically optimal, but human adaptation involves additional factors.
- Published
- 2023
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26. Faster triceps surae muscle cyclic contractions alter muscle activity and whole body metabolic rate.
- Author
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Swinnen W, Hoogkamer W, De Groote F, and Vanwanseele B
- Subjects
- Humans, Isometric Contraction physiology, Leg, Ankle Joint physiology, Muscle, Skeletal physiology, Muscle Contraction physiology
- Abstract
Hundred years ago, Fenn demonstrated that when a muscle shortens faster, its energy liberation increases. Fenn's results were the first of many that led to the general understanding that isometric muscle contractions are energetically cheaper than concentric contractions. However, this evidence is still primarily based on single fiber or isolated (ex vivo) muscle studies and it remains unknown whether this translates to whole body metabolic rate. In this study, we specifically changed the contraction velocity of the ankle plantar flexors and quantified the effects on triceps surae muscle activity and whole body metabolic rate during cyclic plantar flexion (PF) contractions. Fifteen participants performed submaximal ankle plantar flexions (∼1/3 s activation and ∼2/3 s relaxation) on a dynamometer at three different ankle angular velocities: isometric (10° PF), isokinetic at 30°/s (5-15° PF), and isokinetic at 60°/s (0-20° PF) while target torque (25% MVC) and cycle frequency were kept constant. In addition, to directly determine the effect of ankle angular velocity on muscle kinematics we collected gastrocnemius medialis muscle fascicle ultrasound data. As expected, increasing ankle angular velocity increased gastrocnemius medialis muscle fascicle contraction velocity and positive mechanical work ( P < 0.01), increased mean and peak triceps surae muscle activity ( P < 0.01), and considerably increased net whole body metabolic rate ( P < 0.01). Interestingly, the increase in triceps surae muscle activity with fast ankle angular velocities was most pronounced in the gastrocnemius lateralis ( P < 0.05). Overall, our results support the original findings from Fenn in 1923 and we demonstrated that greater triceps surae muscle contraction velocities translate to increased whole body metabolic rate. NEW & NOTEWORTHY Single muscle fiber studies or research on isolated (ex vivo) muscles demonstrated that faster concentric muscle contractions yield increased energy consumption. Here we translated this knowledge to muscle activation and whole body metabolic rate. Increasing ankle angular velocity increased triceps surae contraction velocity and mechanical work, increasing triceps surae muscle activity and substantially elevating whole body metabolic rate. Additionally, we demonstrated that triceps surae muscle activation strategy depends on the mechanical demands of the task.
- Published
- 2023
- Full Text
- View/download PDF
27. Commentaries on Viewpoint: Physiology and fast marathons.
- Author
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Santos-Concejero J, González-Mohíno F, González-Ravé JM, Perrey S, Dewolf AH, Yates BA, Ušaj A, Debevec T, González-Rayas JM, Rayas-Gómez AL, González-Yáñez JM, Lepers R, Stapley P, Louis J, Proessl F, Nikolaidis PT, Knechtle B, Muniz-Pumares D, Hunter B, Bottoms L, Bontemps B, Valenzuela PL, Boullosa D, Del Coso J, Blagrove RC, Hayes PR, Millet GP, Malatesta D, de Almeida Costa Campos Y, Pereira Guimarães M, Macedo Vianna J, Fernandes da Silva S, Silva Marques de Azevedo PH, Paris HL, Leist MA, Lige MT, Malysa W, Oumsang AS, Sinai EC, Hansen RK, Secher NH, Volianitis S, Hottenrott L, Hottenrott K, Gronwald T, Senefeld JW, Fernandes RJ, Vilas-Boas JP, Riveros-Rivera A, Böning D, Craighead DH, Kipp S, Kram R, Zinner C, Sperlich B, Holmberg HC, Muniz-Pardos B, Sutehall S, Angeloudis K, Guppy FM, Bosch A, Pitsiladis Y, Andrade DC, Del Rio R, Ramirez-Campillo R, Lopes TR, Silva BM, Ives SJ, Weyand PG, Brietzke C, Franco-Alvarenga PE, Meireles dos Santos T, Pires FO, Layec G, Hoogkamer W, Balestrini CS, Goss CS, Gabler MC, Escalera A, Bielko SA, and Chapman RF
- Subjects
- Running
- Published
- 2020
- Full Text
- View/download PDF
28. Habitual foot strike pattern does not affect simulated triceps surae muscle metabolic energy consumption during running.
- Author
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Swinnen W, Hoogkamer W, De Groote F, and Vanwanseele B
- Subjects
- Female, Humans, Male, Energy Metabolism, Foot physiology, Muscle, Skeletal metabolism, Running physiology
- Abstract
Foot strike pattern affects ankle joint work and triceps surae muscle-tendon dynamics during running. Whether these changes in muscle-tendon dynamics also affect triceps surae muscle energy consumption is still unknown. In addition, as the triceps surae muscle accounts for a substantial amount of the whole-body metabolic energy consumption, changes in triceps surae energy consumption may affect whole-body metabolic energy consumption. However, direct measurements of muscle metabolic energy consumption during dynamic movements is difficult. Model-based approaches can be used to estimate individual muscle and whole-body metabolic energy consumption based on Hill type muscle models. In this study, we use an integrated experimental and dynamic optimization approach to compute muscle states (muscle forces, lengths, velocities, excitations and activations) of 10 habitual midfoot/forefoot striking and nine habitual rearfoot striking runners while running at 10 and 14 km h
-1 The Achilles tendon stiffness of the musculoskeletal model was adapted to fit experimental ultrasound data of the gastrocnemius medialis muscle during ground contact. Next, we calculated triceps surae muscle and whole-body metabolic energy consumption using four different metabolic energy models provided in the literature. Neither triceps surae metabolic energy consumption ( P >0.35) nor whole-body metabolic energy consumption ( P >0.14) was different between foot strike patterns, regardless of the energy model used or running speed tested. Our results provide new evidence that midfoot/forefoot and rearfoot strike patterns are metabolically equivalent., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)- Published
- 2019
- Full Text
- View/download PDF
29. Effect of habitual foot-strike pattern on the gastrocnemius medialis muscle-tendon interaction and muscle force production during running.
- Author
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Swinnen W, Hoogkamer W, Delabastita T, Aeles J, De Groote F, and Vanwanseele B
- Subjects
- Ankle Joint physiology, Biomechanical Phenomena physiology, Female, Humans, Male, Achilles Tendon physiology, Foot physiology, Muscle, Skeletal physiology, Running physiology
- Abstract
The interaction between gastrocnemius medialis (GM) muscle and Achilles tendon, i.e., muscle-tendon unit (MTU) interaction, plays an important role in minimizing the metabolic cost of running. Foot-strike pattern (FSP) has been suggested to alter MTU interaction and subsequently the metabolic cost of running. However, metabolic data from experimental studies on FSP are inconsistent, and a comparison of MTU interaction between FSP is still lacking. We, therefore, investigated the effect of habitual rearfoot and mid-/forefoot striking on MTU interaction, ankle joint work, and plantar flexor muscle force production while running at 10 and 14 km/h. GM muscle fascicles of 9 rearfoot and 10 mid-/forefoot strikers were tracked using dynamic ultrasonography during treadmill running. We collected kinetic and kinematic data and used musculoskeletal models to determine joint angles and calculate MTU lengths. In addition, we used dynamic optimization to assess plantar flexor muscle forces. During ground contact, GM fascicle shortening ( P = 0.02) and average contraction velocity ( P = 0.01) were 40-45% greater in rearfoot strikers than mid-/forefoot strikers. Differences in contraction velocity were especially prominent during early ground contact. Moreover, GM ( P = 0.02) muscle force was greater during early ground contact in mid-/forefoot strikers than rearfoot strikers. Interestingly, we did not find differences in stretch or recoil of the series elastic element between FSP. Our results suggest that, for the GM, the reduced muscle energy cost associated with lower fascicle contraction velocity in mid-/forefoot strikers may be counteracted by greater muscle forces during early ground contact. NEW & NOTEWORTHY Kinetic and kinematic differences between foot-strike patterns during running imply (not previously reported) altered muscle-tendon interaction. Here, we studied muscle-tendon interaction using ultrasonography. We found greater fascicle contraction velocities and lower muscle forces in rearfoot compared with mid-/forefoot strikers. Our results suggest that the higher metabolic energy demand due to greater fascicle contraction velocities might offset the lower metabolic energy demand due to lower muscle forces in rearfoot compared with mid-/forefoot strikers.
- Published
- 2019
- Full Text
- View/download PDF
30. Applying the cost of generating force hypothesis to uphill running.
- Author
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Hoogkamer W, Taboga P, and Kram R
- Abstract
Historically, several different approaches have been applied to explain the metabolic cost of uphill human running. Most of these approaches result in unrealistically high values for the efficiency of performing vertical work during running uphill, or are only valid for running up steep inclines. The purpose of this study was to reexamine the metabolic cost of uphill running, based upon our understanding of level running energetics and ground reaction forces during uphill running. In contrast to the vertical efficiency approach, we propose that during incline running at a certain velocity, the forces (and hence metabolic energy) required for braking and propelling the body mass parallel to the running surface are less than during level running. Based on this idea, we propose that the metabolic rate during uphill running can be predicted by a model, which posits that (1) the metabolic cost of perpendicular bouncing remains the same as during level running, (2) the metabolic cost of running parallel to the running surface decreases with incline, (3) the delta efficiency of producing mechanical power to lift the COM vertically is constant, independent of incline and running velocity, and (4) the costs of leg and arm swing do not change with incline. To test this approach, we collected ground reaction force (GRF) data for eight runners who ran thirty 30-second trials (velocity: 2.0-3.0 m/s; incline: 0-9°). We also measured the metabolic rates of eight different runners for 17, 7-minute trials (velocity: 2.0-3.0 m/s; incline: 0-8°). During uphill running, parallel braking GRF approached zero for the 9° incline trials. Thus, we modeled the metabolic cost of parallel running as exponentially decreasing with incline. With that assumption, best-fit parameters for the metabolic rate data indicate that the efficiency of producing mechanical power to lift the center of mass vertically was independent of incline and running velocity, with a value of ∼29%. The metabolic cost of uphill running is not simply equal to the sum of the cost of level running and the cost of performing work to lift the body mass against gravity. Rather, it reflects a constant cost of perpendicular bouncing, decreased costs of parallel braking and propulsion and of course the cost of lifting body mass against gravity.
- Published
- 2014
- Full Text
- View/download PDF
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