Dynamical analysis of Quadrupedal-to-Bipedal ‘on the fly’ transitions in walking baboons

Baboons can transition from quadrupedal to bipedal walking ‘on the fly’, i.e. without any significant interruption in their forward movement. Using an inverse approach, planar dynamics are deduced from (lateral view) video-recordings. Starting from the momentum-impulse theorem, possible strategies for such dynamical mode transitions are evaluated, and applied, first to an example sequence. The strategy used in this worked example boils down to: crouch the hind parts and sprint them underneath the rising body centre of mass. Forward accelerations are not in play. Key characteristics of this transition strategy were extracted: progression speed, hip height, step duration(frequency), foot positioning at touchdown with respect to the hip and the body centre of mass (BCoM), and congruity between the moments of the ground reaction force about the BCoM and the rate of change of the total angular moment. Statistical analyses across all available recordings of transitions (15 by 10 individuals) confirm this strategy is always used and is shared across individuals. The costs (in J kg−1 m−1) linked to such ‘on the fly’ transitions were estimated. These approximately only double those of both the preceding quadrupedal and subsequent bipedal walking. Given the short duration of the transition as such (<1 s), it is argued that the energetic costs to change walking posture ‘on the fly’ are negligible when considered in the context of the entire locomotor repertoire of baboons.

Zusammenfassungen zu den Vorträgen sind nachstehend aufgeführt. Die Übertragung der Vorträge findet über das Video-Konferenz-System ZOOM statt. Für die Teilnahme bestehen zwei Möglichkeiten: (1) Internet-Browser (z.B. Firefox, Chrome, Safari, Microsoft Edge ...) oder (2) zu installierender, kostenfreier Client.

Bitte beachten Sie die Datenschutzhinweise zum Einsatz von ZOOM. Einlass ist ca. 10 Minuten vor Beginn.

Wir freuen uns auf Ihre Teilnahme!
Albert Baars