Ultrasound as a Tool to Study Muscle–Tendon Functions during Locomotion: A Systematic Review of Applications

Abstract

Movement science investigating muscle and tendon functions during locomotion utilizes commercial ultrasound imagers built for medical applications. These limit biomechanics research due to their form factor, range of view, and spatio-temporal resolution. This review systematically investigates the technical aspects of applying ultrasound as a research tool to investigate human and animal locomotion. It provides an overview on the ultrasound systems used and of their operating parameters. We present measured fascicle velocities and discuss the results with respect to operating frame rates during recording. Furthermore, we derive why muscle and tendon functions should be recorded with a frame rate of at least 150 Hz and a range of view of 250 mm. Moreover, we analyze why and how the development of better ultrasound observation devices at the hierarchical level of muscles and tendons can support biomechanics research. Additionally, we present recent technological advances and their possible application. We provide a list of recommendations for the development of a more advanced ultrasound sensor system class targeting biomechanical applications. Looking to the future, mobile, ultrafast ultrasound hardware technologies create immense opportunities to expand the existing knowledge of human and animal movement.

A Human-Centered Machine-Learning Approach for Muscle-Tendon Junction Tracking in Ultrasound Images

“…During experimental trials using bulky standard medical US probes, or in special environments (e.g. data collection on impaired subjects) transducers are often displaced [20]. This causes image distortions and can also lead to out-of-plane movements of transducers.…”

“…Image appearances may also vary due to different applications of US systems in experimental setups. Leitner et al [20] have shown that, for example, the Telemed system is widely used to collect data during movement with increased frame-rates at the cost of decreasing image qualities. Other devices, such as the Esaote system, offer transducers with wide probe heads to collect data on movements where larger scale length changes occur, decreasing frame-rates.…”

“…1. b), the area of this anatomical feature is covered by standard-sized linear US arrays [20]. Therefore, this method is widely used and it improves general understanding of muscle-tendon properties and their behaviour in healthy [21] and impaired subjects [16], [22].…”

“…Applied on noisy, real-world US motion data, these optical-flow or matching based methods are prone to errors [26]. This is often due to low frame-rate recordings or poor image qualities of standard medical US systems [20]. One common parameter to quantify US image quality is the contrast-to-noise-ratio (CNR) [27].…”

Techniques for In Vivo Measurement of Ligament and Tendon Strain: A Review

“…39 Ultrasound evaluations have also contributed towards understanding the function of human triceps surae muscles during walking and running. [29][30][31][32][33]101 In these studies, either a single ultrasound transducer was positioned over the medial gastrocnemius (MG) so that the soleus was also visible, 32 or two transducers were placed over the MG and soleus. 80 The MG and soleus fascicle lengths and pennation angles were then measured using an automated tracking algorithm, and motion-capture derived knee and ankle joint kinematics were further used to estimate MG and soleus muscle-tendon unit lengths.…”