{"id":{"repo_id":"sherbrooke","oai_identifier":"oai:usherbrooke.scholaris.ca:11143/15799"},"canonical_url":"https://search.dev.ndltd.org/etd/sherbrooke/oai:usherbrooke.scholaris.ca:11143/15799","repository":{"repo_id":"sherbrooke","name":"Université de Sherbrooke","base_url":"https://usherbrooke.scholaris.ca/server/oai/request"},"display":{"title":"Forelimb and hindlimb adjustments to treadmill speed during quadrupedal locomotion after a lateral spinal hemisection in adult cats.","abstract":"The ability to attain and sustain moderately fast walking speeds is critically important for various locomotor tasks in animals, including humans. In animals, it is vital for survival, to capture prey or escape from predators and to find a mate. In humans, modulating walking speed is important for several activities, including sports, exercise and effective community ambulation, such as safely crossing a street. Following spinal cord injury (SCI), a common deficit includes an inability to attain and sustain moderately fast speeds. The goal of the present study was to describe adjustments to different speeds (0.4m/s-0.8m/s) before and after an incomplete SCI in the cat model. Experimental analyses were performed before, one week (H1) and eight weeks (H2) after a lateral spinal hemisection between the 5-6th thoracic vertebrae in 8 cats. We found that 4 cats were unable to perform 10-15 steps consistently on the treadmill at the fastest speeds (0.9m/s-1.0m/s) following hemisection (H1 and H2). Speed-dependent modulation of cycle, stance and swing durations were maintained in all cats, albeit with a significant decrease in forelimb cycle duration and increase in hindlimb cycle duration. The dissociation of fore-hindlimb rhythms lead to the appearance of 2-1 coordination which was not influenced by stepping speed. Step and stride length modulation was maintained after SCI, however, as speeds increased, hindlimb paw contact remained significantly more caudal relative to the hip at H1 and H2. Interlimb phase intervals were relatively unaffected by walking speed or lateral hemisection. Speed-dependent modulation of support period durations were conserved following SCI such that double support durations increased, while triple and quadruple support periods decreased with increasing speed. We did note a significant decrease in triple support period durations where two hindlimbs and one forelimb are in contact with the treadmill, along with a significant increase in quadruple support frequency and duration. As speeds increased, electromyographic (EMG) activity increased in all muscles tested, with the exception of the ipsilesional knee extensor, right vastus lateralis (RVL). We also noted a decreased RVL activation duration along with increased ipsilesional Sartorius (RSRT, hip flexor/knee extensor) burst duration across all speeds after hemisection. RSRT showed significant activation during the stance phase at both timepoints following hemisection, presumably to stabilize the knee post-SCI. Taken together, the present results demonstrate that felines can make the necessary adjustments to their locomotor pattern across a moderate range of speeds following hemisection at mid-thoracic levels. However, many of these cats could not attain the fastest speeds, which may be attributed to the various changes that occurred following hemisection. Future studies may seek to explore which adjustments limit SCI patients and quadrupeds most from attaining faster speeds to optimize recovery and ambulation after injury.","abstract_html":"The ability to attain and sustain moderately fast walking speeds is critically important for various locomotor tasks in animals, including humans. In animals, it is vital for survival, to capture prey or escape from predators and to find a mate. In humans, modulating walking speed is important for several activities, including sports, exercise and effective community ambulation, such as safely crossing a street. Following spinal cord injury (SCI), a common deficit includes an inability to attain and sustain moderately fast speeds. The goal of the present study was to describe adjustments to different speeds (0.4m/s-0.8m/s) before and after an incomplete SCI in the cat model. Experimental analyses were performed before, one week (H1) and eight weeks (H2) after a lateral spinal hemisection between the 5-6th thoracic vertebrae in 8 cats. We found that 4 cats were unable to perform 10-15 steps consistently on the treadmill at the fastest speeds (0.9m/s-1.0m/s) following hemisection (H1 and H2). Speed-dependent modulation of cycle, stance and swing durations were maintained in all cats, albeit with a significant decrease in forelimb cycle duration and increase in hindlimb cycle duration. The dissociation of fore-hindlimb rhythms lead to the appearance of 2-1 coordination which was not influenced by stepping speed. Step and stride length modulation was maintained after SCI, however, as speeds increased, hindlimb paw contact remained significantly more caudal relative to the hip at H1 and H2. Interlimb phase intervals were relatively unaffected by walking speed or lateral hemisection. Speed-dependent modulation of support period durations were conserved following SCI such that double support durations increased, while triple and quadruple support periods decreased with increasing speed. We did note a significant decrease in triple support period durations where two hindlimbs and one forelimb are in contact with the treadmill, along with a significant increase in quadruple support frequency and duration. As speeds increased, electromyographic (EMG) activity increased in all muscles tested, with the exception of the ipsilesional knee extensor, right vastus lateralis (RVL). We also noted a decreased RVL activation duration along with increased ipsilesional Sartorius (RSRT, hip flexor/knee extensor) burst duration across all speeds after hemisection. RSRT showed significant activation during the stance phase at both timepoints following hemisection, presumably to stabilize the knee post-SCI. Taken together, the present results demonstrate that felines can make the necessary adjustments to their locomotor pattern across a moderate range of speeds following hemisection at mid-thoracic levels. However, many of these cats could not attain the fastest speeds, which may be attributed to the various changes that occurred following hemisection. Future studies may seek to explore which adjustments limit SCI patients and quadrupeds most from attaining faster speeds to optimize recovery and ambulation after injury.","abstract_has_math":false,"creators":["Doelman, Adam"],"institution":"Université de Sherbrooke","degree_name":"M. Sc.","degree_level":"Maîtrise","degree_discipline":"Physiologie","degree_department":null,"school":null,"contributors":[],"advisors":["Frigon, Alain"],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019","date_published":"2019","updated_at":"2026-07-27T21:07:47Z","subjects":["Locomotion","Speed","Spinal Cord Injury","Vitesse","Lésion incomplète à la moelle épinière"],"languages":["fr","en"],"rights":[],"rights_urls":["http://creativecommons.org/licenses/by-nd/2.5/ca/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11143/15799","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Frigon, Alain"]},{"key":"dc:creator","label":"Author","values":["Doelman, Adam"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2019-07-26T17:20:05Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2019-07-26T17:20:05Z"]},{"key":"dc:date.issued","label":"Date","values":["2019"]},{"key":"dc:publisher","label":"Institution","values":["Université de Sherbrooke"]},{"key":"dc:type","label":"Dc Type","values":["Mémoire de maîtrise"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physiologie"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Maîtrise"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M. 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In animals, it is vital for survival, to capture prey or escape from predators and to find a mate. In humans, modulating walking speed is important for several activities, including sports, exercise and effective community ambulation, such as safely crossing a street. Following spinal cord injury (SCI), a common deficit includes an inability to attain and sustain moderately fast speeds. The goal of the present study was to describe adjustments to different speeds (0.4m/s-0.8m/s) before and after an incomplete SCI in the cat model. Experimental analyses were performed before, one week (H1) and eight weeks (H2) after a lateral spinal hemisection between the 5-6th thoracic vertebrae in 8 cats. We found that 4 cats were unable to perform 10-15 steps consistently on the treadmill at the fastest speeds (0.9m/s-1.0m/s) following hemisection (H1 and H2). Speed-dependent modulation of cycle, stance and swing durations were maintained in all cats, albeit with a significant decrease in forelimb cycle duration and increase in hindlimb cycle duration. The dissociation of fore-hindlimb rhythms lead to the appearance of 2-1 coordination which was not influenced by stepping speed. Step and stride length modulation was maintained after SCI, however, as speeds increased, hindlimb paw contact remained significantly more caudal relative to the hip at H1 and H2. Interlimb phase intervals were relatively unaffected by walking speed or lateral hemisection. Speed-dependent modulation of support period durations were conserved following SCI such that double support durations increased, while triple and quadruple support periods decreased with increasing speed. We did note a significant decrease in triple support period durations where two hindlimbs and one forelimb are in contact with the treadmill, along with a significant increase in quadruple support frequency and duration. As speeds increased, electromyographic (EMG) activity increased in all muscles tested, with the exception of the ipsilesional knee extensor, right vastus lateralis (RVL). We also noted a decreased RVL activation duration along with increased ipsilesional Sartorius (RSRT, hip flexor/knee extensor) burst duration across all speeds after hemisection. RSRT showed significant activation during the stance phase at both timepoints following hemisection, presumably to stabilize the knee post-SCI. Taken together, the present results demonstrate that felines can make the necessary adjustments to their locomotor pattern across a moderate range of speeds following hemisection at mid-thoracic levels. However, many of these cats could not attain the fastest speeds, which may be attributed to the various changes that occurred following hemisection. Future studies may seek to explore which adjustments limit SCI patients and quadrupeds most from attaining faster speeds to optimize recovery and ambulation after injury.","La capacité à atteindre et à maintenir des vitesses de marche modérées est d'une importance capitale pour diverses tâches locomotrices chez les animaux comme capturer une proie ou échapper à des prédateurs. Chez l'humain, cette capacité est essentielle au quotidien pour évoluer efficacement dans notre environnement comme par exemple accélérer pour traverser la rue en toute sécurité. Suite à une lésion incomplète de la moelle épinière (LIME), un des déficits engendrés est l’incapacité à atteindre et à maintenir des vitesses modérées. Le but de la présente étude est de décrire les ajustements à différentes vitesses (0.4-0.8 m/s) avant et après une LIME dans le modèle du chat. Des analyses expérimentales ont été effectuées avant, une semaine (H1) et huit semaines (H2) après une hémisection latérale de la moelle épinière au niveau de la 5-6 ème vertèbre thoracique chez 8 chats adultes. Nous avons constaté que 4 chats étaient incapables de réaliser 10 à 15 pas de manière constante sur le tapis roulant aux vitesses les plus rapides (0.9 et 1.0 m/s) après l'hémisection à H1 et H2, respectivement. La modulation de la durée du cycle de marche, la phase d’appui et de balancement en fonction de la vitesse a été maintenue chez tous les chats. Cependant, une diminution significative de la durée du cycle des membres antérieurs et une augmentation de la durée du cycle des membres postérieurs a pu être observée. Cette dissociation du rythme antérieur-postérieur fait apparaître une coordination 2-1 mais qui ne semble toutefois pas être influencée par la vitesse de marche. La modulation de la longueur du pas et de la foulée a été maintenue après la LIME. Par ailleurs, à mesure que la vitesse du tapis augmente, le contact de la patte du membre postérieur est resté nettement plus caudal par rapport à la hanche à H1 et H2. Les intervalles de phase ont été relativement peu affectés par la vitesse du tapis roulant ou l'hémisection latérale. Bien que la modulation de la durée des périodes de support en fonction de la vitesse ait été conservée après la LIME, la durée des périodes de double support a augmenté tandis que les périodes de triple et quadruple support ont diminué avec l'augmentation de la vitesse. Nous avons noté une diminution significative de la durée de la période de triple support pendant laquelle deux membres postérieurs et un membre antérieur sont en contact avec le tapis roulant, ainsi qu'une augmentation significative de la fréquence et de la durée de quatre supports. De plus, avec l’augmentation de la vitesse de marche, nous avons observé une augmentation de l'activité électromyographique dans tous les muscles testés, à l'exception du vaste latéral ipsilatérale à la lésion (RVL; extenseur du genou). Nous avons également noté une diminution de la durée d'activation du RVL ainsi qu'une augmentation de la durée d’activation du muscle sartorius ipsilatéral à la lésion (RSRT; fléchisseur de la hanche) à toutes les vitesses après l'hémisection. Nous avons également remarqué que l'activation du RSRT se poursuivait pendant la phase d'appui, probablement pour stabiliser le genou. Dans leur ensemble, les résultats actuels démontrent que les chats peuvent apporter les ajustements nécessaires à leur patron locomoteur sur une plage de vitesses modérée suivant une lésion incomplète de la moelle épinière. Cependant, 4 des 8 chats n'ont pas été capables d'atteindre des vitesses plus rapides, ce qui peut être attribué aux divers changements survenus après l'hémisection. Des études futures pourraient chercher à déterminer quels ajustements limitent cette capacité à atteindre des vitesses plus rapides afin d'optimiser la récupération et une marche fonctionnelle après la blessure."]},{"key":"dc:title","label":"Title","values":["Forelimb and hindlimb adjustments to treadmill speed during quadrupedal locomotion after a lateral spinal hemisection in adult cats."]}]}],"canonical_facts":{"dc:contributor.advisor":["Frigon, Alain"],"dc:creator":["Doelman, Adam"],"dc:date.accessioned":["2019-07-26T17:20:05Z"],"dc:date.available":["2019-07-26T17:20:05Z"],"dc:date.issued":["2019"],"dc:description.abstract":["The ability to attain and sustain moderately fast walking speeds is critically important for various locomotor tasks in animals, including humans. In animals, it is vital for survival, to capture prey or escape from predators and to find a mate. In humans, modulating walking speed is important for several activities, including sports, exercise and effective community ambulation, such as safely crossing a street. Following spinal cord injury (SCI), a common deficit includes an inability to attain and sustain moderately fast speeds. The goal of the present study was to describe adjustments to different speeds (0.4m/s-0.8m/s) before and after an incomplete SCI in the cat model. Experimental analyses were performed before, one week (H1) and eight weeks (H2) after a lateral spinal hemisection between the 5-6th thoracic vertebrae in 8 cats. We found that 4 cats were unable to perform 10-15 steps consistently on the treadmill at the fastest speeds (0.9m/s-1.0m/s) following hemisection (H1 and H2). Speed-dependent modulation of cycle, stance and swing durations were maintained in all cats, albeit with a significant decrease in forelimb cycle duration and increase in hindlimb cycle duration. The dissociation of fore-hindlimb rhythms lead to the appearance of 2-1 coordination which was not influenced by stepping speed. Step and stride length modulation was maintained after SCI, however, as speeds increased, hindlimb paw contact remained significantly more caudal relative to the hip at H1 and H2. Interlimb phase intervals were relatively unaffected by walking speed or lateral hemisection. Speed-dependent modulation of support period durations were conserved following SCI such that double support durations increased, while triple and quadruple support periods decreased with increasing speed. We did note a significant decrease in triple support period durations where two hindlimbs and one forelimb are in contact with the treadmill, along with a significant increase in quadruple support frequency and duration. As speeds increased, electromyographic (EMG) activity increased in all muscles tested, with the exception of the ipsilesional knee extensor, right vastus lateralis (RVL). We also noted a decreased RVL activation duration along with increased ipsilesional Sartorius (RSRT, hip flexor/knee extensor) burst duration across all speeds after hemisection. RSRT showed significant activation during the stance phase at both timepoints following hemisection, presumably to stabilize the knee post-SCI. Taken together, the present results demonstrate that felines can make the necessary adjustments to their locomotor pattern across a moderate range of speeds following hemisection at mid-thoracic levels. However, many of these cats could not attain the fastest speeds, which may be attributed to the various changes that occurred following hemisection. Future studies may seek to explore which adjustments limit SCI patients and quadrupeds most from attaining faster speeds to optimize recovery and ambulation after injury.","La capacité à atteindre et à maintenir des vitesses de marche modérées est d'une importance capitale pour diverses tâches locomotrices chez les animaux comme capturer une proie ou échapper à des prédateurs. Chez l'humain, cette capacité est essentielle au quotidien pour évoluer efficacement dans notre environnement comme par exemple accélérer pour traverser la rue en toute sécurité. Suite à une lésion incomplète de la moelle épinière (LIME), un des déficits engendrés est l’incapacité à atteindre et à maintenir des vitesses modérées. Le but de la présente étude est de décrire les ajustements à différentes vitesses (0.4-0.8 m/s) avant et après une LIME dans le modèle du chat. Des analyses expérimentales ont été effectuées avant, une semaine (H1) et huit semaines (H2) après une hémisection latérale de la moelle épinière au niveau de la 5-6 ème vertèbre thoracique chez 8 chats adultes. Nous avons constaté que 4 chats étaient incapables de réaliser 10 à 15 pas de manière constante sur le tapis roulant aux vitesses les plus rapides (0.9 et 1.0 m/s) après l'hémisection à H1 et H2, respectivement. La modulation de la durée du cycle de marche, la phase d’appui et de balancement en fonction de la vitesse a été maintenue chez tous les chats. Cependant, une diminution significative de la durée du cycle des membres antérieurs et une augmentation de la durée du cycle des membres postérieurs a pu être observée. Cette dissociation du rythme antérieur-postérieur fait apparaître une coordination 2-1 mais qui ne semble toutefois pas être influencée par la vitesse de marche. La modulation de la longueur du pas et de la foulée a été maintenue après la LIME. Par ailleurs, à mesure que la vitesse du tapis augmente, le contact de la patte du membre postérieur est resté nettement plus caudal par rapport à la hanche à H1 et H2. Les intervalles de phase ont été relativement peu affectés par la vitesse du tapis roulant ou l'hémisection latérale. Bien que la modulation de la durée des périodes de support en fonction de la vitesse ait été conservée après la LIME, la durée des périodes de double support a augmenté tandis que les périodes de triple et quadruple support ont diminué avec l'augmentation de la vitesse. Nous avons noté une diminution significative de la durée de la période de triple support pendant laquelle deux membres postérieurs et un membre antérieur sont en contact avec le tapis roulant, ainsi qu'une augmentation significative de la fréquence et de la durée de quatre supports. De plus, avec l’augmentation de la vitesse de marche, nous avons observé une augmentation de l'activité électromyographique dans tous les muscles testés, à l'exception du vaste latéral ipsilatérale à la lésion (RVL; extenseur du genou). Nous avons également noté une diminution de la durée d'activation du RVL ainsi qu'une augmentation de la durée d’activation du muscle sartorius ipsilatéral à la lésion (RSRT; fléchisseur de la hanche) à toutes les vitesses après l'hémisection. Nous avons également remarqué que l'activation du RSRT se poursuivait pendant la phase d'appui, probablement pour stabiliser le genou. Dans leur ensemble, les résultats actuels démontrent que les chats peuvent apporter les ajustements nécessaires à leur patron locomoteur sur une plage de vitesses modérée suivant une lésion incomplète de la moelle épinière. Cependant, 4 des 8 chats n'ont pas été capables d'atteindre des vitesses plus rapides, ce qui peut être attribué aux divers changements survenus après l'hémisection. Des études futures pourraient chercher à déterminer quels ajustements limitent cette capacité à atteindre des vitesses plus rapides afin d'optimiser la récupération et une marche fonctionnelle après la blessure."],"dc:identifier.uri":["http://hdl.handle.net/11143/15799"],"dc:language.iso":["fr","en"],"dc:publisher":["Université de Sherbrooke"],"dc:rights.uri":["http://creativecommons.org/licenses/by-nd/2.5/ca/"],"dc:subject":["Locomotion","Speed","Spinal Cord Injury","Vitesse","Lésion incomplète à la moelle épinière"],"dc:title":["Forelimb and hindlimb adjustments to treadmill speed during quadrupedal locomotion after a lateral spinal hemisection in adult cats."],"dc:type":["Mémoire de maîtrise"],"thesis:degree_discipline":["Physiologie"],"thesis:degree_level":["Maîtrise"],"thesis:degree_name":["M. Sc."],"thesis:institution_name":["Faculté de médecine et des sciences de la santé"]},"updated_at":"2026-07-27T21:07:47Z"}