Efficient elastic tissue motions indicate general motor skill | Scientific Reports [MANY novel measureables that can be age-related]
Biomechanics in everyday life – Praneeth Namburi
even the muscle-neuron aging axis can be captured if you track physiological signals [eg in the MIT immersion lab]
https://advanced.onlinelibrary.wiley.com/doi/10.1002/adhm.202403712
raman
experts across fields share common characteristics: fewer tremors, reduced transverse muscle motions, and more effective muscle length changes.
Our findings reveal that experts exhibit reduced transverse muscle motions and tremors compared to non-experts and intermediates, raising an important mechanistic question: do experts actively suppress these inefficiencies through neural dampening mechanisms, or do they employ movement strategies that inherently prevent these motions from occurring? This distinction has significant implications for training interventions. If experts primarily engage neural dampening mechanisms—such as phase cancellation in the 10 Hz range by spinal circuits69—then training could focus on developing these systems. Alternatively, if experts adopt movement patterns that inherently minimize these inefficiencies, training might better focus on kinematic restructuring of movements.
Stress can amplify physiological tremor—β-adrenergic stimulation70 or caffeine71,72 increase tremor amplitude—and typically elevates baseline muscle tone via tonic muscle activation73. One could argue that experts’ lower tremor levels simply reflect their comfort under pressure to perform. However, three observations contradict this stress-only explanation
https://imes.mit.edu/people/anthony-brian
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they’ve done studies on rigidity vs asymmetrical activation of younger vs older piano players (is there an effect of aging muscles) [some older people are rigid but more economical/efficient with muscle activations]. Longitudinal studies.
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During movement, healthy individuals typically experience subtle, high-frequency oscillations known as physiological tremors 44,45,46,47. The 8-12 Hz component of physiological tremors is readily detected on the skin, and has a multifactorial etiology based on the mechanical properties of tissues and the nervous system48,49,50. Physiological tremors are benign51, often invisible to the naked eye51, and do not compromise the motion of body segments, unlike some pathological tremors associated with conditions such as Parkinson’s disease48,52. In this paper, “tremor” refers only to the 8-12 Hz component of the physiological tremor52,53 and not to any other type of tremor51.
Transverse muscle motions occur orthogonal to the direction of force generation and therefore do not contribute to the external work done by the muscle to actuate joints. Similarly, physiological tremors are oscillatory movements that do not contribute to the net joint actuation work done by the muscle. Therefore, we denote transverse muscle motions and physiological tremors as inefficiencies in muscle motions. We refer to muscle motions as being more efficient when transverse muscle motions and tremors are minimized. Note that this is different from metabolic efficiency, which is not studied in this work. Lastly, we define muscle length changes as being more effective when the ratio of body segment motions to muscle length changes is higher—that is, when smaller muscle length changes correspond to similar body segment motions. Our findings reveal that intermediates and experts have more effective muscle length changes than non-experts, and experts have more efficient muscle motions than both intermediates and non-experts.
mocap as in motioncapture