Non-invasive measurement method for hardness in muscular tissues

Intermuscular pressure between synergistic muscles correlates with muscle force

“…This finding coincides with the fact that muscle hardness and longitudinal stiffness increase with force generation (Morgan, 1977;Horikawa et al, 1993;Ettema and Huijing, 1994;Murayama et al, 2005Murayama et al, , 2012.…”

“…(3) Also, muscle hardness, i.e. the resistance offered by the muscle against perpendicular pressure, considerably increases with rising force during contraction (Horikawa et al, 1993;Murayama et al, 2005Murayama et al, , 2012. On the basis of these facts, the following simple explanatory approach is suggested (Fig.…”

Parameters Representing Muscle Tone, Elasticity and Stiffness of Biceps Brachii in Healthy Older Males: Symmetry and Within-Session Reliability Using the MyotonPRO

“…New measures of muscular properties are being developed, offering an in vivo, objective, clinical, non-invasive alternative to subjective assessments. These include tensiomyography or TMG, which uses electrical stimulation to elicit muscle oscillations to measure contraction time and muscle displacement [7]; various devices that measure tissue stiffness, such as muscle 'hardness' meters [8], myotonometry, which compresses (≥ 1 ≤ 2 seconds) the muscle to record tissue displacement [9,10], and a mechano-acoustic indentor system that records tissue displacement to measure non-linear elastic properties [11]; and the recently introduced Myoton technology, which elicits mechanically induced oscillations [12][13][14][15][16][17][18][19][20][21]. The different technologies have their relative advantages.…”

Evaluation of Muscle Tension in Hemiplegia Patients with a Real-time Monitoring System during High Intensity Laser Therapy

“…Each curve corresponds to a degree of muscle resistance when specific force (0.5-1 kg) was applied on the surface of the skin. Hemiplegic patients have stiffer muscles with more non-uniform muscle fibers and with a shorter muscle fiber length, and these abnormalities lead to increased passive stiffness [21][22][23][24][25][26][27]. As a consequence, the abnormal muscle tissue resulted in lower resistance, and the displacement per unit force is in inverse proportion to muscle stiffness.…”

“…This behavior can be described using a two-layer spring model, as shown in Fig. 3(b) [23]. With this two-layer spring model, the force-displacement relation in the early stages of displacement is given by…”