Mechanical output in jumps of marmosets (Callithrix jacchus)

Abstract

In this study we determined the mechanical output of common marmosets (Callithrix jacchus) during jumping. Vertical ground reaction forces were measured in 18 animals while they jumped from an instrumented crossbar to a crossbar located 70 cm higher. From the vertical force time histories, we calculated the rate of change of mechanical energy of the centre of mass (dE/dt). The mean value of dE/dt during the push-off amounted to 51.8±6.2 W kg −1 body mass, and the peak value to 116.4±17.6 W kg −1 body mass. We used these values in combination with masses of leg muscles, determined in two specimens, to estimate mean and peak values of dE/dt of 430 and 970 W kg −1 muscle, respectively. These values are higher than values reported in the literature for jumps of humans and bonobos, but smaller than those of jumps of bushbabies. Surprisingly, the mean value of dE/dt of 430 W kg −1 muscle was close to the maximal power output of 516 W kg −1 muscle reported in the literature for isokinetic contractions of rat medial gastrocnemius, one of the fastest mammalian muscles. Further study of the force-velocity relationship of muscle tissue of small primates is indicated. KEY WORDS: Biomechanics, Muscle power, Muscle work, Mass-specific, Primates INTRODUCTIONOne of the challenging goals in movement science is to relate the total mechanical output of an animal during locomotor tasks to the output of the elements of the musculoskeletal system. The limits of mechanical output are approached in jumping, a locomotor task that is important for survival in many animals because it plays a role in catching prey or escaping from predators. Many studies have been conducted on the mechanics of jumping of various species (Aerts, 1998;Bobbert, 2001;Harris and Steudel, 2002;Henry et al., 2005;Peplowski and Marsh, 1997;Roberts et al., 2011;Scholz et al., 2006). In humans, the mechanical output in jumping has been successfully reproduced and analyzed with the help of musculoskeletal models (Bobbert, 2001;Bobbert and van Soest, 2001;Nagano et al., 2005;Pandy et al., 1990). However, humans are relatively poor jumpers compared with nonhuman primates such as bonobos (Scholz et al., 2006), gibbons (Channon et al., 2012) and bushbabies (Aerts, 1998). The jumping performance of small primates is especially puzzling. If a human musculoskeletal model is downscaled to the size of a 0.3 kg bushbaby, jump height drops from ~40 cm to ~10 cm (Bobbert, 2013). It is easy to understand why jump height does not remain constant with geometric downscaling: for jump height to remain constant, the vertical take- off velocity of the centre of mass (COM) must remain constant, but with shorter segments this would require higher angular velocities and hence higher muscle shortening velocities, and at higher shortening velocities muscle mechanical output would be hampered more by the force-velocity relationship (Bobbert, 2013). If small primates are able to jump higher than humans, their bodies must be anatomically and physiologically different from those of huma...

Muscle contractile properties as an explanation of the higher mean power output in marmosets than humans during jumping

“…P FMS,peak of different species needs to be compared within the same experimental set-up using the same solutions in order to make definitive statements about possible differences in power-generating capacity. In this context it is interesting to note, as we did before (Bobbert et al, 2014), that the reported P MMS,mean delivered by marmosets and bushbabies during a vertical jump is similar to or even higher than P MMS,peak measured for supramaximally stimulated in situ rat m. gastrocnemius medialis (i.e. 530 W kg −1 muscle mass) at 35°C (Furrer et al, 2013).…”

“…For instance, for the Muscle mass-specific peak power (P MMS,peak ) was derived from the whole-muscle F-V relationship, which was estimated by adding at each velocity the force output of the relative fractions of different fibre types. (A,B) F-V (dashed) and P-V (solid) curve of marmoset (thick) and human (thin) VL (A) and GM (B Bobbert et al, 2014). These values are 6.3-fold and 3.7-fold those reported for humans, respectively, and 3.3-and 1.6-fold those shown here for the marmoset.…”

“…These differences are similar to differences reported for mean power output (both P BMS,mean and P MMS,mean ) delivered during push-off of a vertical jump. In marmoset, P BMS,mean was 1.9 times and P MMS,mean 2.4 times that of human (Bobbert et al, 2014). These results indicate that during a maximal vertical jump the higher in vivo mean power output (both P BMS,mean and P MMS,mean ) delivered by marmosets compared with that by humans is mainly caused by a larger proportion of fast muscle fibres in the main leg extensor muscles of the marmoset.…”

“…In the animal kingdom there are large differences among species in performance during vertical jumping (Marsh and John-Alder, 1994;Aerts, 1998;Harris and Steudel, 2002;Legreneur et al, 2010;Bobbert et al, 2014). For comparison among different species, the performance of jumping is best defined as body mass-specific mean power output (P BMS,mean ) or leg muscle mass-specific mean power output (P MMS,mean ) during push-off.…”

“…For comparison among different species, the performance of jumping is best defined as body mass-specific mean power output (P BMS,mean ) or leg muscle mass-specific mean power output (P MMS,mean ) during push-off. Recently, in vivo mean power output during the push-off in vertical jumping of the common marmoset, Callithrix jacchus (Linnaeus 1758), was shown to be 52 W kg −1 P BMS,mean and 430 W kg −1 P MMS,mean (Bobbert et al, 2014). These values are twice those reported for humans (Homo sapiens L.; 27 W kg −1 P BMS,mean and 181 W kg −1 P BMS,mean , respectively; Bobbert et al, 2014).…”