À l’holocène, le développement de l'agriculture par les populations humaines a modifié la morphologique du squelette humain. Dans ce cadre, plusieurs recherches se sont intéressées à la biomécanique des populations passées et modernes. Elles supposent qu’une activité physique répétée affecte la structure de l’os. Cette réponse osseuse est analysée par les propriétés géométriques de l’os qui permettent de reconstruire le comportement passé et présent des individus. La distribution osseuse en coupe a donc été étudiée sur les membres supérieurs et inférieurs de populations centrafricaines (du Cameroun et de la République Démocratique du Congo). La première hypothèse de ce mémoire est la suivante, les agriculteurs centrafricains, au mode de vie sédentaire, auraient les membres supérieurs plus robustes, tandis que les chasseurs-cueilleurs, plus mobiles, auraient les membres inférieurs plus robustes. La deuxième hypothèse suppose que les populations d’un milieu/terrain plus accidenté auraient les membres, supérieurs et/ou inférieurs, plus robustes. Nos résultats indiquent plutôt que les chasseurs-cueilleurs et les agriculteurs ont la même robustesse générale, bien que les peuples non sédentarisés soient plus robustes à la mi-diaphyse des radius droits. Contrairement à ce qui était attendu, les fémurs sont plus résistants (CSA) chez les agriculteurs, quand ils sont standardisés par la masse corporelle. En revanche, la moitié supérieure des tibias semblent être plus robuste chez les chasseurs-cueilleurs, quand les propriétés sont standardisées par la longueur de l’os. Les radius et les ulnas des chasseurs-cueilleurs vivant en forêt et en montagne ont la même robustesse. Enfin, seule la section distale des fibulas est plus résistante (CSA) chez les chasseurs-cueilleurs de la montagne que chez les chasseurs-cueilleurs de la forêt. En conclusion, ce mémoire ne nous permet pas d’affirmer que la transition vers l’agriculture s’accompagne d’une réduction de la mobilité et de la robustesse en Afrique centrale. En revanche, il montre que ces individus sont quand même influencés par leur stratégie de subsistance. Un plus grand échantillon est nécessaire pour mieux documenter la transition agricole et l’influence du milieu sur la structure osseuse en Afrique centrale. / The emergence of farming in the Holocene had major impacts on human populations. Many biomechanical studies have explored past and recent populations and have suggested that physical activity affects bone structure. Cross-sectional geometric properties of bones are measured to reconstruct past and recent human behavior. The present study analyses bone cross-sectional geometry of upper and lower limbs long bones of Central African populations (from Cameroon and the Democratic Republic of Congo). This study is based on the premise that agriculturalists, a sedentary group using their upper limbs for farming activities, have more robust upper limbs, while hunter-gatherers, that have an extremely mobile lifestyle, have more robust lower limbs. In addition, it is assumed that populations in more rugged environments/terrains would have more robust upper and/or lower limbs. Against expectation, the upper limbs of non-sedentary and sedentary populations have the same robusticity, although the right radius midshafts of hunter-gatherers are more robust. The femora are more robust in agriculturalists when the significant properties are normalized by body mass. In contrast, the upper part of the tibiae is more robust in hunter-gatherers when the properties are standardised by bone length. Against expectation, it was found that the upper limbs (radii and ulnae) of hunter-gatherers living in the lowland forests and in the mountains have the same robustness. Meanwhile, for the lower limbs, the fibula is more robust in people living in the mountains than those in the forest. In conclusion, these findings do not allow us to assert that the transition to agriculture is accompanied by a reduction in mobility and robusticity in the lower limbs or an increase in robusticity of the upper limb. Nonetheless, this study suggests that individuals are influenced by their economic strategy. However, a larger sample will be needed to better evaluate the role of the transition to agriculture on bone structure in Central Africa.

O nosso objetivo foi de avaliar evolutivamente a perda da força muscular e das habilidades motoras, bem como a progressão da distribuição da fraqueza muscular nos diferentes segmentos dos membros superiores em pacientes com distrofia muscular de Duchenne em corticoterapia. Selecionamos seguintes testes de fácil aplicação: Teste de força Manual Muscular Escala Medical Research Council; Teste ABC provas de coordenação visual-motora e fatigabilidade provas n° 1, 3, 7 e 8; Grau funcional de Brooke; Índice de Barthel. Os testes foram aplicados em 40 pacientes com idades entre 5 e 15 anos, deambulantes e não deambulantes, os quais foram avaliados três vezes, com intervalos de seis meses entre cada avaliação. Os resultados mostraram que a progressão da distribuição da força muscular nos membros superiores ocorreu dos segmentos proximais para os distais em todos os pacientes e foi maior nos pacientes não deambulantes e com maior idade. O ato de escrever (pegada no lápis e/ou caneta) não foi influenciado pela progressão; no entanto, o aumento da fatigabilidade foi um fator limitante contribuindo para a redução do ritmo e da qualidade da escrita. O grau funcional de Brooke confirmou a variação das medidas de força muscular e nas atividades de vida diária o nível de dependência foi maior nos pacientes com maior idade, acontecendo nestes compensações funcionais importantes que lhes permitiram realizar a atividade de forma adaptada. / Our aim was to analyze the progression of the involvement of muscle strength and functional motor hability as well as the progression of the weakness pattern in the upper limbs of children with Duchenne muscular dystrophy who were receiving steroid therapy. We evaluated 40 patients with DMD, aged 5-15 years, by using the following simple tests: MRC score based on the upper limbs muscles; ABC tests number 1, 3, 7 and 8 for assessing visual motor coordination and fatigability; Brooke functional ability scale and modified Barthel index. All boys were evaluated every 6 months along a period of 18 months. The loss of muscular strength showed a proximal to distal progression and was greater in non- ambulant and in older patients. The act of writing (to hold pencil or pen) was not influenced by the progression; however, the fatigability increased and was a limiting factor for the speed and the quality of the hand writing. The Brooke functional ability scale confirmed the changes in the muscular strength. The performance in daily activities showed a greater dependence in the older patients who adopted functional compensations for performing the activities in an adapted way.

O nosso objetivo foi de avaliar evolutivamente a perda da força muscular e das habilidades motoras, bem como a progressão da distribuição da fraqueza muscular nos diferentes segmentos dos membros superiores em pacientes com distrofia muscular de Duchenne em corticoterapia. Selecionamos seguintes testes de fácil aplicação: Teste de força Manual Muscular Escala Medical Research Council; Teste ABC provas de coordenação visual-motora e fatigabilidade provas n° 1, 3, 7 e 8; Grau funcional de Brooke; Índice de Barthel. Os testes foram aplicados em 40 pacientes com idades entre 5 e 15 anos, deambulantes e não deambulantes, os quais foram avaliados três vezes, com intervalos de seis meses entre cada avaliação. Os resultados mostraram que a progressão da distribuição da força muscular nos membros superiores ocorreu dos segmentos proximais para os distais em todos os pacientes e foi maior nos pacientes não deambulantes e com maior idade. O ato de escrever (pegada no lápis e/ou caneta) não foi influenciado pela progressão; no entanto, o aumento da fatigabilidade foi um fator limitante contribuindo para a redução do ritmo e da qualidade da escrita. O grau funcional de Brooke confirmou a variação das medidas de força muscular e nas atividades de vida diária o nível de dependência foi maior nos pacientes com maior idade, acontecendo nestes compensações funcionais importantes que lhes permitiram realizar a atividade de forma adaptada. / Our aim was to analyze the progression of the involvement of muscle strength and functional motor hability as well as the progression of the weakness pattern in the upper limbs of children with Duchenne muscular dystrophy who were receiving steroid therapy. We evaluated 40 patients with DMD, aged 5-15 years, by using the following simple tests: MRC score based on the upper limbs muscles; ABC tests number 1, 3, 7 and 8 for assessing visual motor coordination and fatigability; Brooke functional ability scale and modified Barthel index. All boys were evaluated every 6 months along a period of 18 months. The loss of muscular strength showed a proximal to distal progression and was greater in non- ambulant and in older patients. The act of writing (to hold pencil or pen) was not influenced by the progression; however, the fatigability increased and was a limiting factor for the speed and the quality of the hand writing. The Brooke functional ability scale confirmed the changes in the muscular strength. The performance in daily activities showed a greater dependence in the older patients who adopted functional compensations for performing the activities in an adapted way.