Title : Ultrasound quadriceps depth and sit-to-stand power as biomarkers of muscle function and quality
Abstract:
Introduction: The evaluation of muscle function and quality is complex, and its difficult in the implementation in clinical practice. Grip strength has been used as a proxy for the ability to generate body force, but there is controversy about this. Isokinetic assessment integrates characteristics of strength, power and muscle work during concentric and eccentric activities, and its implementation in clinical practice is not feasible. Muscle ultrasound has been proposed to be integrated into the evaluation of muscle quality, and recording quadriceps depth can provide clinically relevant information to be integrated into muscle assessment.
Purpose: To propose the IMQ-Sit to Stand Power/Quadriceps Depth as a clinical parameter to assess muscle function and quality.
Methods: Descriptive, cross-sectional and analytical study. People over 18 years were included, self-referred to as healthy, after signing an informed consent form, eliminating subjects who did not complete the evaluations. Variables studied: grip strength, Densitometry, Isokinesis, Ultrasound, Sit to Stand, Sit to stand power, and the muscle quality index for StS/PQ power were calculated.
Results: 26 subjects (18 women) were included, with an average age of 48.5 years (SD=22.6; range 18 to 79). The PQ observed a strong correlation (from 0.699 to 0.869, with p<0.05) with variables of grip strength and isokinesis (strength, power and work) at low and high speed, as well as with variables of arm, leg and appendicular lean mass obtaining strong correlations (from .746 to .861, p=<0.05) and with moderate functional variables for Sit to Stand 5 (r=-0.559; p<0.05), Sit to Stand 10 (r=-0.589; p<0.005) and Sit to Stand 30 sec (r=0.512; p<0.05). The StS power observed a moderate to strong correlation with the strength parameters of the grip and isokinetic (from r = 0.695 to r = 0.831; p < 0.05), as well as strong for the functional tests StS 5 (r = -0.859; p < 0.05), StS 10 (r = -0.874; p < 0.05), StS 30 sec (r = 0.866; p < 0.05). The IMQ was calculated considering sit to stand power and PQ (IMQ-PStS / PQ), observing moderate correlation with the tests StS5 (r = -0.601, p < 0.05), 10 (r = -0.570; p < 0.05) and 30s (r = 646; p < 0.05).
Conclusions: The IMQ-PotStS/PQ can be a useful indicator to evaluate functional performance, highlighting the importance of associating strength and isokinetic evaluations together with StS power, with evaluations of physical and functional performance, representing a feasible option for implementation in daily clinical practice.
