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Adamantios Arampatzis - One of the best experts on this subject based on the ideXlab platform.
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Impact of Altered Gastrocnemius Morphometrics and Fascicle Behavior on Walking Patterns in Children With Spastic Cerebral Palsy.
Frontiers in physiology, 2020Co-Authors: Matthias Hösl, Annika Kruse, Markus Tilp, Martin Svehlik, Harald Böhm, Antonia Zehentbauer, Adamantios ArampatzisAbstract:Spastic cerebral palsy (SCP) affects neural control, deteriorates muscle morphometrics, and may progressively impair functional walking ability. Upon passive testing, gastrocnemius medialis (GM) muscle bellies or fascicles are typically shorter, thinner, and less extensible. Relationships between muscle and gait parameters might help to understand gait pathology and pathogenesis of spastic muscles. The current aim was to link resting and dynamic GM morphometrics and contractile fascicle behavior (both excursion and velocity) during walking to determinants of gait. We explored the associations between gait variables and ultrasonography of the GM muscle belly captured during rest and during gait in children with SCP [n = 15, gross motor function classification system (GMFCS) levels I and II, age: 7-16 years] and age-matched healthy peers (n = 17). The SCP children's plantar flexors were 27% weaker. They walked 12% slower with more knee flexion produced 42% less peak ankle push-off power (all p < 0.05) and 7/15 landed on their forefoot. During the stance phase, fascicles in SCP on average operated on 9% shorter Length (normalized to rest Length) and displayed less and slower fascicle shortening (37 and 30.6%, respectively) during push-off (all p ≤ 0.024). Correlation analyses in SCP patients revealed that (1) longer-resting fascicles and thicker muscle bellies are positively correlated with walking speed and negatively to knee flexion (r = 0.60-0.69, p < 0.0127) but not to better ankle kinematics; (2) reduced muscle strength was associated with the extent of eccentric fascicle excursion (r = -0.57, p = 0.015); and (3) a shorter Operating Length of the fascicles was correlated with push-off power (r = -0.58, p = 0.013). Only in controls, a correlation (r = 0.61, p = 0.0054) between slower fascicle shortening velocity and push-off power was found. Our results indicate that a thicker gastrocnemius muscle belly and longer gastrocnemius muscle fascicles may be reasonable morphometric properties that should be targeted in interventions for individuals with SCP, since GM muscle atrophy may be related to decreases in walking speed and undesired knee flexion during gait. Furthermore, children with SCP and weaker gastrocnemius muscle may be more susceptible to chronic eccentric muscle overloading. The relationship between shorter Operating Length of the fascicles and push-off power may further support the idea of a compensation mechanism for the longer sarcomeres found in children with SCP. Nevertheless, more studies are needed to support our explorative findings.
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the force Length velocity potential of the human soleus muscle is related to the energetic cost of running
Proceedings of The Royal Society B: Biological Sciences, 2019Co-Authors: Sebastian Bohm, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force–Length–velocity relationships, the muscle force potential is determined by the Operating Length and velocity, which affects the energetic cost of contraction. During running,...
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The force–Length–velocity potential of the human soleus muscle is related to the energetic cost of running
Proceedings. Biological sciences, 2019Co-Authors: Sebastian Bohm, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force–Length–velocity relationships, the muscle force potential is determined by the Operating Length and velocity, which affects the energetic cost of contraction. During running,...
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Operating Length and velocity of human vastus lateralis muscle during walking and running
Scientific Reports, 2018Co-Authors: Sebastian Bohm, Robert Marzilger, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force-Length-velocity relationships, the muscle force potential during locomotion is determined by the Operating fibre Length and velocity. We measured fascicle and muscle-tendon unit Length and velocity as well as the activity of the human vastus lateralis muscle (VL) during walking and running. Furthermore, we determined the VL force-Length relationship experimentally and calculated the force-Length and force-velocity potentials (i.e. fraction of maximum force according to the force-Length-velocity curves) for both gaits. During the active state of the stance phase, fascicles showed significantly (p < 0.05) smaller Length changes (walking: 9.2 ± 4.7% of optimal Length (L0); running: 9.0 ± 8.4%L0) and lower velocities (0.46 ± 0.36 L0/s; 0.03 ± 0.83 L0/s) compared to the muscle-tendon unit (walking: 19.7 ± 5.3%L0, −0.94 ± 0.32 L0/s; running: 34.5 ± 5.8%L0, −2.59 ± 0.41 L0/s). The VL fascicles operated close to optimum Length (L0 = 9.4 ± 0.11 cm) in both walking (8.6 ± 0.14 cm) and running (10.1 ± 0.19 cm), resulting in high force-Length (walking: 0.92 ± 0.08; running: 0.91 ± 0.14) and force-velocity (0.91 ± 0.08; 0.97 ± 0.13) potentials. For the first time we demonstrated that, in contrast to the current general conception, the VL fascicles operate almost isometrically and close to L0 during the active state of the stance phase of walking and running. The findings further verify an important contribution of the series-elastic element to VL fascicle dynamics.
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Operating Length and velocity of human vastus lateralis muscle during walking and running
Scientific Reports, 2018Co-Authors: Sebastian Bohm, Robert Marzilger, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force-Length-velocity relationships, the muscle force potential during locomotion is determined by the Operating fibre Length and velocity. We measured fascicle and muscle-tendon unit Length and velocity as well as the activity of the human vastus lateralis muscle (VL) during walking and running. Furthermore, we determined the VL force-Length relationship experimentally and calculated the force-Length and force-velocity potentials (i.e. fraction of maximum force according to the force-Length-velocity curves) for both gaits. During the active state of the stance phase, fascicles showed significantly (p
Sebastian Bohm - One of the best experts on this subject based on the ideXlab platform.
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the force Length velocity potential of the human soleus muscle is related to the energetic cost of running
Proceedings of The Royal Society B: Biological Sciences, 2019Co-Authors: Sebastian Bohm, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force–Length–velocity relationships, the muscle force potential is determined by the Operating Length and velocity, which affects the energetic cost of contraction. During running,...
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The force–Length–velocity potential of the human soleus muscle is related to the energetic cost of running
Proceedings. Biological sciences, 2019Co-Authors: Sebastian Bohm, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force–Length–velocity relationships, the muscle force potential is determined by the Operating Length and velocity, which affects the energetic cost of contraction. During running,...
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Operating Length and velocity of human vastus lateralis muscle during walking and running
Scientific Reports, 2018Co-Authors: Sebastian Bohm, Robert Marzilger, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force-Length-velocity relationships, the muscle force potential during locomotion is determined by the Operating fibre Length and velocity. We measured fascicle and muscle-tendon unit Length and velocity as well as the activity of the human vastus lateralis muscle (VL) during walking and running. Furthermore, we determined the VL force-Length relationship experimentally and calculated the force-Length and force-velocity potentials (i.e. fraction of maximum force according to the force-Length-velocity curves) for both gaits. During the active state of the stance phase, fascicles showed significantly (p < 0.05) smaller Length changes (walking: 9.2 ± 4.7% of optimal Length (L0); running: 9.0 ± 8.4%L0) and lower velocities (0.46 ± 0.36 L0/s; 0.03 ± 0.83 L0/s) compared to the muscle-tendon unit (walking: 19.7 ± 5.3%L0, −0.94 ± 0.32 L0/s; running: 34.5 ± 5.8%L0, −2.59 ± 0.41 L0/s). The VL fascicles operated close to optimum Length (L0 = 9.4 ± 0.11 cm) in both walking (8.6 ± 0.14 cm) and running (10.1 ± 0.19 cm), resulting in high force-Length (walking: 0.92 ± 0.08; running: 0.91 ± 0.14) and force-velocity (0.91 ± 0.08; 0.97 ± 0.13) potentials. For the first time we demonstrated that, in contrast to the current general conception, the VL fascicles operate almost isometrically and close to L0 during the active state of the stance phase of walking and running. The findings further verify an important contribution of the series-elastic element to VL fascicle dynamics.
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Operating Length and velocity of human vastus lateralis muscle during walking and running
Scientific Reports, 2018Co-Authors: Sebastian Bohm, Robert Marzilger, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force-Length-velocity relationships, the muscle force potential during locomotion is determined by the Operating fibre Length and velocity. We measured fascicle and muscle-tendon unit Length and velocity as well as the activity of the human vastus lateralis muscle (VL) during walking and running. Furthermore, we determined the VL force-Length relationship experimentally and calculated the force-Length and force-velocity potentials (i.e. fraction of maximum force according to the force-Length-velocity curves) for both gaits. During the active state of the stance phase, fascicles showed significantly (p
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Operating Length and velocity of human m vastus lateralis fascicles during vertical jumping
Royal Society Open Science, 2017Co-Authors: Maria Nikolaidou, Sebastian Bohm, Robert Marzilger, Falk Mersmann, Adamantios ArampatzisAbstract:Humans achieve greater jump height during a counter-movement jump (CMJ) than in a squat jump (SJ). However, the crucial difference is the mean mechanical power output during the propulsion phase, which could be determined by intrinsic neuro-muscular mechanisms for power production. We measured M. vastus lateralis (VL) fascicle Length changes and activation patterns and assessed the force–Length, force–velocity and power–velocity potentials during the jumps. Compared with the SJ, the VL fascicles operated on a more favourable portion of the force–Length curve (7% greater force potential, i.e. fraction of VL maximum force according to the force–Length relationship) and more disadvantageous portion of the force–velocity curve (11% lower force potential, i.e. fraction of VL maximum force according to the force–velocity relationship) in the CMJ, indicating a reciprocal effect of force–Length and force–velocity potentials for force generation. The higher muscle activation (15%) could therefore explain the moderately greater jump height (5%) in the CMJ. The mean fascicle-shortening velocity in the CMJ was closer to the plateau of the power–velocity curve, which resulted in a greater (15%) power–velocity potential (i.e. fraction of VL maximum power according to the power–velocity relationship). Our findings provide evidence for a cumulative effect of three different mechanisms—i.e. greater force–Length potential, greater power–velocity potential and greater muscle activity—for an advantaged power production in the CMJ contributing to the marked difference in mean mechanical power (56%) compared with SJ.
Damian G Shannon - One of the best experts on this subject based on the ideXlab platform.
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on the ascent the soleus Operating Length is conserved to the ascending limb of the force Length curve across gait mechanics in humans
The Journal of Experimental Biology, 2012Co-Authors: Jonas Rubenson, Neville J Pires, Gavin J Pinniger, Damian G ShannonAbstract:SUMMARY The region over which skeletal muscles operate on their force–Length (F–L) relationship is fundamental to the mechanics, control and economy of movement. Yet surprisingly little experimental data exist on normalized Length Operating ranges of muscle during human gait, or how they are modulated when mechanical demands (such as force output) change. Here we explored the soleus muscle (SOL) Operating Lengths experimentally in a group of healthy young adults by combining subject-specific F–L relationships with in vivo muscle imaging during gait. We tested whether modulation of Operating Lengths occurred between walking and running, two gaits that require different levels of force production and different muscle–tendon mechanics, and examined the relationship between optimal fascicle Lengths ( L 0 ) and normalized Operating Lengths during these gaits. We found that the mean active muscle Lengths reside predominantly on the ascending limbs of the F–L relationship in both gaits (walk, 0.70–0.94 L 0 ; run, 0.65–0.99 L 0 ). Furthermore, the mean normalized muscle Length at the time of the peak activation of the muscle was the same between the two gaits (0.88 L 0 ). The active Operating Lengths were conserved, despite a fundamentally different fascicle strain pattern between walking (stretch–shorten cycle) and running (near continuous shortening). Taken together, these findings indicate that the SOL Operating Length is highly conserved, despite gait-dependent differences in muscle–tendon dynamics, and appear to be preferentially selected for stable force production compared with optimal force output (although Length-dependent force capacity is high when maximal forces are expected to occur). Individuals with shorter L 0 undergo smaller absolute muscle excursions ( P L 0 . The correlation between L 0 and absolute Length change was not explained on the basis of muscle moment arms or joint excursion, suggesting that regulation of muscle strain may occur via tendon stretch.
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On the ascent: the soleus Operating Length is conserved to the ascending limb of the force-Length curve across gait mechanics in humans.
The Journal of experimental biology, 2012Co-Authors: Jonas Rubenson, Neville J Pires, Heok O Loi, Gavin J Pinniger, Damian G ShannonAbstract:The region over which skeletal muscles operate on their force-Length (F-L) relationship is fundamental to the mechanics, control and economy of movement. Yet surprisingly little experimental data exist on normalized Length Operating ranges of muscle during human gait, or how they are modulated when mechanical demands (such as force output) change. Here we explored the soleus muscle (SOL) Operating Lengths experimentally in a group of healthy young adults by combining subject-specific F-L relationships with in vivo muscle imaging during gait. We tested whether modulation of Operating Lengths occurred between walking and running, two gaits that require different levels of force production and different muscle-tendon mechanics, and examined the relationship between optimal fascicle Lengths (L(0)) and normalized Operating Lengths during these gaits. We found that the mean active muscle Lengths reside predominantly on the ascending limbs of the F-L relationship in both gaits (walk, 0.70-0.94 L(0); run, 0.65-0.99 L(0)). Furthermore, the mean normalized muscle Length at the time of the peak activation of the muscle was the same between the two gaits (0.88 L(0)). The active Operating Lengths were conserved, despite a fundamentally different fascicle strain pattern between walking (stretch-shorten cycle) and running (near continuous shortening). Taken together, these findings indicate that the SOL Operating Length is highly conserved, despite gait-dependent differences in muscle-tendon dynamics, and appear to be preferentially selected for stable force production compared with optimal force output (although Length-dependent force capacity is high when maximal forces are expected to occur). Individuals with shorter L(0) undergo smaller absolute muscle excursions (P
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On the ascent: the soleus Operating Length is conserved to the ascending limb of the force–Length curve across gait mechanics in humans
Journal of Experimental Biology, 2012Co-Authors: Jonas Rubenson, Neville J Pires, Heok O Loi, Gavin J Pinniger, Damian G ShannonAbstract:SUMMARY The region over which skeletal muscles operate on their force–Length (F–L) relationship is fundamental to the mechanics, control and economy of movement. Yet surprisingly little experimental data exist on normalized Length Operating ranges of muscle during human gait, or how they are modulated when mechanical demands (such as force output) change. Here we explored the soleus muscle (SOL) Operating Lengths experimentally in a group of healthy young adults by combining subject-specific F–L relationships with in vivo muscle imaging during gait. We tested whether modulation of Operating Lengths occurred between walking and running, two gaits that require different levels of force production and different muscle–tendon mechanics, and examined the relationship between optimal fascicle Lengths ( L 0 ) and normalized Operating Lengths during these gaits. We found that the mean active muscle Lengths reside predominantly on the ascending limbs of the F–L relationship in both gaits (walk, 0.70–0.94 L 0 ; run, 0.65–0.99 L 0 ). Furthermore, the mean normalized muscle Length at the time of the peak activation of the muscle was the same between the two gaits (0.88 L 0 ). The active Operating Lengths were conserved, despite a fundamentally different fascicle strain pattern between walking (stretch–shorten cycle) and running (near continuous shortening). Taken together, these findings indicate that the SOL Operating Length is highly conserved, despite gait-dependent differences in muscle–tendon dynamics, and appear to be preferentially selected for stable force production compared with optimal force output (although Length-dependent force capacity is high when maximal forces are expected to occur). Individuals with shorter L 0 undergo smaller absolute muscle excursions ( P L 0 . The correlation between L 0 and absolute Length change was not explained on the basis of muscle moment arms or joint excursion, suggesting that regulation of muscle strain may occur via tendon stretch.
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RESEARCH ARTICLE On the ascent: the soleus Operating Length is conserved to the ascending limb of the force-Length curve across gait mechanics in humans
2012Co-Authors: Jonas Rubenson, Neville J Pires, Heok O Loi, Gavin J Pinniger, Damian G ShannonAbstract:SUMMARY The region over which skeletal muscles operate on their force–Length (F–L) relationship is fundamental to the mechanics, control and economy of movement. Yet surprisingly little experimental data exist on normalized Length Operating ranges of muscle during human gait, or how they are modulated when mechanical demands (such as force output) change. Here we explored the soleus muscle (SOL) Operating Lengths experimentally in a group of healthy young adults by combining subject-specific F–L relationships with in vivo muscle imaging during gait. We tested whether modulation of Operating Lengths occurred between walking and running, two gaits that require different levels of force production and different muscle–tendon mechanics, and examined the relationship between optimal fascicle Lengths (L0) and normalized Operating Lengths during these gaits. We found that the mean active muscle Lengths reside predominantly on the ascending limbs of the F–L relationship in both gaits (walk, 0.70–0.94 L0; run, 0.65–0.99 L0). Furthermore, the mean normalized muscle Length at the time of the peak activation of the muscle was the same between the two gaits (0.88 L0). The active Operating Lengths were conserved, despite a fundamentally different fascicle strain pattern between walking (stretch–shorten cycle) and running (near continuous shortening). Taken together, these findings indicate that the SOL Operating Length is highly conserved, despite gait-dependent differences in muscle–tendon dynamics, and appear to be preferentially selected for stable force production compared with optimal force output (although Length-dependent force capacity is high when maximal forces are expected to occur). Individuals with shorter L0 undergo smaller absolute muscle excursions (P
Thomas L. Daniel - One of the best experts on this subject based on the ideXlab platform.
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Submaximal power output from the dorsolongitudinal flight muscles of the hawkmoth Manduca sexta.
Journal of Experimental Biology, 2004Co-Authors: Thomas L. DanielAbstract:SUMMARY To assess the extent to which the power output of a synchronous insect flight muscle is maximized during flight, we compared the maximum potential power output of the mesothoracic dorsolongitudinal (dl1) muscles of Manduca sexta to their power output in vivo. Holding temperature and cycle frequency constant at 36°C and 25 Hz, respectively, we varied the phase of activation, mean Length and strain amplitude. Under in vivo conditions measured in tethered flight, the dl1 muscles generated only 40–67% of their maximum potential power output. Compared to the in vivo phase of activation, the phase that maximized power output was advanced by 12% of the cycle period, and the Length that maximized power output was 10% longer than the in vivo Operating Length.
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Submaximal power output from the dorsolongitudinal flight muscles of the hawkmoth Manduca sexta.
The Journal of experimental biology, 2004Co-Authors: Thomas L. DanielAbstract:To assess the extent to which the power output of a synchronous insect flight muscle is maximized during flight, we compared the maximum potential power output of the mesothoracic dorsolongitudinal (dl1) muscles of Manduca sexta to their power output in vivo. Holding temperature and cycle frequency constant at 36 degrees C and 25 Hz, respectively, we varied the phase of activation, mean Length and strain amplitude. Under in vivo conditions measured in tethered flight, the dl1 muscles generated only 40-67% of their maximum potential power output. Compared to the in vivo phase of activation, the phase that maximized power output was advanced by 12% of the cycle period, and the Length that maximized power output was 10% longer than the in vivo Operating Length.
Falk Mersmann - One of the best experts on this subject based on the ideXlab platform.
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the force Length velocity potential of the human soleus muscle is related to the energetic cost of running
Proceedings of The Royal Society B: Biological Sciences, 2019Co-Authors: Sebastian Bohm, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force–Length–velocity relationships, the muscle force potential is determined by the Operating Length and velocity, which affects the energetic cost of contraction. During running,...
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The force–Length–velocity potential of the human soleus muscle is related to the energetic cost of running
Proceedings. Biological sciences, 2019Co-Authors: Sebastian Bohm, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force–Length–velocity relationships, the muscle force potential is determined by the Operating Length and velocity, which affects the energetic cost of contraction. During running,...
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Operating Length and velocity of human vastus lateralis muscle during walking and running
Scientific Reports, 2018Co-Authors: Sebastian Bohm, Robert Marzilger, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force-Length-velocity relationships, the muscle force potential during locomotion is determined by the Operating fibre Length and velocity. We measured fascicle and muscle-tendon unit Length and velocity as well as the activity of the human vastus lateralis muscle (VL) during walking and running. Furthermore, we determined the VL force-Length relationship experimentally and calculated the force-Length and force-velocity potentials (i.e. fraction of maximum force according to the force-Length-velocity curves) for both gaits. During the active state of the stance phase, fascicles showed significantly (p < 0.05) smaller Length changes (walking: 9.2 ± 4.7% of optimal Length (L0); running: 9.0 ± 8.4%L0) and lower velocities (0.46 ± 0.36 L0/s; 0.03 ± 0.83 L0/s) compared to the muscle-tendon unit (walking: 19.7 ± 5.3%L0, −0.94 ± 0.32 L0/s; running: 34.5 ± 5.8%L0, −2.59 ± 0.41 L0/s). The VL fascicles operated close to optimum Length (L0 = 9.4 ± 0.11 cm) in both walking (8.6 ± 0.14 cm) and running (10.1 ± 0.19 cm), resulting in high force-Length (walking: 0.92 ± 0.08; running: 0.91 ± 0.14) and force-velocity (0.91 ± 0.08; 0.97 ± 0.13) potentials. For the first time we demonstrated that, in contrast to the current general conception, the VL fascicles operate almost isometrically and close to L0 during the active state of the stance phase of walking and running. The findings further verify an important contribution of the series-elastic element to VL fascicle dynamics.
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Operating Length and velocity of human vastus lateralis muscle during walking and running
Scientific Reports, 2018Co-Authors: Sebastian Bohm, Robert Marzilger, Falk Mersmann, Alessandro Santuz, Adamantios ArampatzisAbstract:According to the force-Length-velocity relationships, the muscle force potential during locomotion is determined by the Operating fibre Length and velocity. We measured fascicle and muscle-tendon unit Length and velocity as well as the activity of the human vastus lateralis muscle (VL) during walking and running. Furthermore, we determined the VL force-Length relationship experimentally and calculated the force-Length and force-velocity potentials (i.e. fraction of maximum force according to the force-Length-velocity curves) for both gaits. During the active state of the stance phase, fascicles showed significantly (p
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Operating Length and velocity of human m vastus lateralis fascicles during vertical jumping
Royal Society Open Science, 2017Co-Authors: Maria Nikolaidou, Sebastian Bohm, Robert Marzilger, Falk Mersmann, Adamantios ArampatzisAbstract:Humans achieve greater jump height during a counter-movement jump (CMJ) than in a squat jump (SJ). However, the crucial difference is the mean mechanical power output during the propulsion phase, which could be determined by intrinsic neuro-muscular mechanisms for power production. We measured M. vastus lateralis (VL) fascicle Length changes and activation patterns and assessed the force–Length, force–velocity and power–velocity potentials during the jumps. Compared with the SJ, the VL fascicles operated on a more favourable portion of the force–Length curve (7% greater force potential, i.e. fraction of VL maximum force according to the force–Length relationship) and more disadvantageous portion of the force–velocity curve (11% lower force potential, i.e. fraction of VL maximum force according to the force–velocity relationship) in the CMJ, indicating a reciprocal effect of force–Length and force–velocity potentials for force generation. The higher muscle activation (15%) could therefore explain the moderately greater jump height (5%) in the CMJ. The mean fascicle-shortening velocity in the CMJ was closer to the plateau of the power–velocity curve, which resulted in a greater (15%) power–velocity potential (i.e. fraction of VL maximum power according to the power–velocity relationship). Our findings provide evidence for a cumulative effect of three different mechanisms—i.e. greater force–Length potential, greater power–velocity potential and greater muscle activity—for an advantaged power production in the CMJ contributing to the marked difference in mean mechanical power (56%) compared with SJ.