Kinematic analysis of treadmill locomotion of tree shrews, Tupaia glis (Scandentia : Tupaiidae)

The cineradiographic analysis of the treadmill locomotion of tree shrews, T upaia glis comprises walk, trot, and gallop. At symmetrical gaits, T. glis accelerates primarily by increasing step frequency but at gallop, step leng th is increased by including a suspension period. During all gaits, the sit e of foot down is directly below the eye. The femur is in horizontal orient ation at foot down, at lift off humerus and tibia are parallel to the groun d. At the end of the stance phase elbow and knee joint are more extended du ring symmetrical gaits than at gallop (30-40 degrees). Biphasic shoulder jo int movements observable during symmetrical gaits are reduced to monophasic movements at gallop. The onsets of flexion and extension movements are mos tly before foot down and lift off. Body propulsion is mainly achieved by ac tion of the proximal limb segments (scapula: 42-43 % during all gaits, 'pel vic movement': 42 % at gallop). For the first time, kinematics of the inter vertebral thoracic and lumbar joints were calculated from X-ray films. Addi tive sagittal spine movements occur in the caudad thoracic and lumbar inter vertebral joints and contribute substantially to body propulsion. The analy sed kinematic and metric parameters of I: glis are common in mammals of sma ll to medium size and seem to be independent of the taxonomic group of the animal.