How Running Give Us a High Expectations to Overcome Neurological Disorders

Whether chasing down dinner, pushing a stroller up a hill or running errands for a neighbor, we can take joy in the effort. And the more physically active you are, the more rewarding these experiences become. One of the ways that regular exercise changes your brain is by increasing the density of binding sites for endocannabinoids. Spring-like leg behavior is a general feature of mammalian bouncing gaits, such as running and hopping. Although increases in step frequency at a given running speed are known to increase the stiffness of the leg spring (kleg) in non-amputees, little is known about stiffness regulation in unilateral transfemoral amputees. Thus Consequently, the unilateral transfemoral amputees attained the desired step frequency in the unaffected limb, but were unable to match the three highest step frequencies using their affected limbs

The influence of in-vivo mechanical behaviour of the Achilles tendon on the mechanics, energetics and apparent efficiency of bouncing gaits

In this study, we used kinematic, kinetic, metabolic and ultrasound analysis to investigate the role of elastic energy utilisation on the mechanical and physiological demands of a movement task that primarily involves the plantar-flexors muscles (hopping) to determine the contribution of tendon work to total mechanical work and its relationship with apparent efficiency (AE) in bouncing gaits. Metabolic power (PMET) and (positive) mechanical power at the whole-body level (PMEC) were measured during hopping at different frequencies (2, 2.5, 3 and 3.5 Hz). The (positive) mechanical power produced during the Achilles tendon recoil phase (PTEN) was obtained by integrating ultrasound data with an inverse dynamic approach. As a function of hopping frequency, PMEC decreased steadily and PMET exhibited a U-shape behaviour, with a minimum at about 3 Hz. AE (PMEC/PMET) showed an opposite trend and was maximal (about 0.50) at the same frequency when also PTEN was the highest. Positive correlations were observed: i) between PTEN and AE (AE=0.22+0.15.PTEN, R2=0.67, P<0.001) and the intercept of this relationship indicates the value of AE that should be expected when tendon work is nil; ii) between AE and tendon gearing (Gt=DMTU length/Dmuscle belly length) (R2=0.50, P<0.001), a high Gt indicates that the muscle is contracting more isometrically thus allowing the movement to be more economical (and efficient); iii) between Gt and PTEN (R2=0.73, P<0.001) and this indicates that Gt could play an important role in the tendon's capability to store and release mechanical power.

Examining the accuracy of trackways for predicting gait selection and speed of locomotion

Background Using Froude numbers (Fr) and relative stride length (stride length: hip height), trackways have been widely used to determine the speed and gait of an animal. This approach, however, is limited by the ability to estimate hip height accurately and by the lack of information related to the substrate properties when the tracks were made, in particular for extinct fauna. By studying the Svalbard ptarmigan moving on snow, we assessed the accuracy of trackway predictions from a species-specific model and two additional Fr based models by ground truthing data extracted from videos as the tracks were being made. Results The species-specific model accounted for more than 60% of the variability in speed for walking and aerial running, but only accounted for 19% when grounded running, likely due to its stabilizing role while moving faster over a changing substrate. The error in speed estimated was 0-35% for all gaits when using the species-specific model, whereas Fr based estimates produced errors up to 55%. The highest errors were associated with the walking gait. The transition between pendular to bouncing gaits fell close to the estimates using relative stride length described for other extant vertebrates. Conversely, the transition from grounded to aerial running appears to be species specific and highly dependent on posture and substrate. Conclusion Altogether, this study highlights that using trackways to derive predictions on the locomotor speed and gait, using stride length as the only predictor, are problematic as accurate predictions require information from the animal in question.

Examining the accuracy of trackways for predicting gait selection and speed of locomotion

Background Using Froude numbers (Fr) and relative stride length (stride length: hip height), trackways have been widely used to determine the speed and gait of an animal. This approach, however, is limited by the ability to estimate hip height accurately and by the lack of information related to the substrate properties when the tracks were made, in particular for extinct fauna. By studying the Svalbard ptarmigan moving on snow, we assessed the accuracy of trackway predictions from a species-specific model and two additional Fr based models by ground truthing data extracted from videos as the tracks were being made.Results The species-specific model accounted for more than 60% of the variability in speed for walking and aerial running, but only accounted for 19% when grounded running, likely due to its stabilizing role while moving faster over a changing substrate. The error in speed estimated was 0-35% for all gaits when using the species-specific model, whereas Fr based estimates produced errors up to 55%. The highest errors were associated with the walking gait. The transition between pendular to bouncing gaits fell close to the estimates using relative stride length described for other extant vertebrates. Conversely, the transition from grounded to aerial running appears to be species specific and highly dependent on posture and substrate.Conclusion Altogether, this study highlights that using trackways to derive predictions on the locomotor speed and gait, using stride length as the only predictor, are problematic as accurate predictions require information from the animal in question.