The Proto-Aging study aims to define experimental protocols and guidelines to enable the development of musculoskeletal models (digital twins) of elderly people, with the ultimate goal to comprehensively characterize frail elders from a biomechanical standpoint. It is typical for the elderly to present with weakness, slowed movements and reduced levels of physical activity, all of which may be related to the loss of muscle force (dynapenia). Unfortunately, to date, the primary cause for dynapenia is difficult to identify. Digital twins may help to this end, but their development remains critical as it requires a specialized skillset and experimental data for model personalisation. In this study, where the investigators will recruit a small group of frail elders and a cohort of healthy young individuals, all participants will undergo the following examinations: (i) gait assessment, (ii) maximal voluntary isometric contraction (MVIC) test, (iii) superimposed neuromuscular electrical stimulation, and (iv) full lower limb magnetic resonance imaging. Surface electromyography data will further be collected while the subjects perform both the gait assessment and the MVIC test. Last, clinical questionnaires will be administered, and the subjects will be asked to perform additional clinical measures (i.e., hand-grip test, bioelectrical impedance analysis). At the end of the study, a reduced version of the experimental protocol will be developed, with the intent to provide clinicians with a protocol that can be deployed in clinical settings, accounting for the observed reliability and repeatability of each measure, the required level of expertise, and the associated costs and time expenditure.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
25
Magnetic resonance images, electromyography and dynamometry data will be used, together with data from the gait assessment and clinical questionnaires/measures, to characterize the biomechanics of the participants, and to develop and inform personalised musculoskeletal models
IRCCS Istituto Ortopedico Rizzoli
Bologna, Italy
Muscle volume
Full lower limb MRI data will be acquired with subjects in supine position. Individual muscle volumes (in cm3) will be segmented using commercial software and stored in anonymized form.
Time frame: at baseline (Day 0)
MVIC Torque
Dynamometry data will be acquired while participants perform a MVIC leg extension test. The maximum torque values (Nm) measured over three repetitions will be recorded. These correspond to the values observed in correspondence of the plateaux of force, developed over a sustained contraction
Time frame: at baseline (Day 0)
Muscle Inhibition level
The difference between the maximal force exerted during the MVIC test (voluntary contraction) and that achieved when the muscles are electrically stimulated (involuntary contraction) will be computed
Time frame: at baseline (Day 0)
Co-contraction index (CCI)
Experimental EMG data will be recorded from the major lower limb muscles involved in the knee extension, while participants perform a maximal voluntary isometric contraction on a dynamometer (i.e., MVIC test to quantify muscle strength). The co-contraction index, defined as the relative activation of agonist and antagonist muscles (for this task: quadriceps and hamstrings) in the act of kicking (MVIC test).
Time frame: at baseline (Day 0)
Body kinematics
A standard gait assessment will be performed where motion capture data will be collected. Joint angles will be extracted to identify abnormal gait patterns.
Time frame: at baseline (Day 0)
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