Use of Tactile Stiffness to Detect Fatigue in the Latissimus Dorsi Muscle

Abstract

In clinical settings, no method has been established to examine the fatigue of a latissimus dorsi muscle (LDM) preconditioned for cardiomyoplasty. We examined the feasibility of measuring muscle stiffness (tactile stiffness) to evaluate muscle fatigue in situ using our tactile sensor. We stimulated canine LDM with burst pacing and monitored both stiffness and tension to determine their relationship. In both dissected LDM and LDM in situ, the decrements of these parameters during burst pacing were compared between preconditioned and unconditioned LDM. In measurement in situ, the sensor probe was placed on the LDM through a small incision. Strong statistical correlation was shown between stiffness and tension (r = 0.935). In decrements of stiffness in situ, there were statistically significant differences between preconditioned and unconditioned LDM. Our tactile sensor system can provide an efficient method for evaluating fatigue of muscles in situ without measuring muscle tension.

Effects of Thermotherapy with a Bath Additive Containing a Vasodilator on Chronic Shoulder-Neck Pain -Comparison with the Existing Remedies

“…In addition, no notable events such as hospital visits or use of medications, which could affect the evaluations, were reported by the subjects in any group during the entire test period. The scores of the feelings of shoulder tension and pain decreased significantly in all groups during the first 2 weeks (days 0-14) with the use of KYN, and then increased significantly during the next 2 weeks (days [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28], when the treatment with KYN was replaced by the conventional remedies, as shown in Table 1. On the other hand, the score of the difficulties in the movement of the shoulder joint significantly decreased in groups A and B during the initial 2 weeks (days 0-14), but did not change during the next 2 weeks (days 14-28), while no significant changes during the entire period (days 0-28) were found.…”

“…Thus, we evaluated muscle hardness, t-Hb, StO 2 and PTT on the center of the trapezius. A tactile sensor system was used to evaluate the hardness on the trapezius, because of the better correlation between the observed data and sense of fingertips compared with other types of hardness meters 20,27) . In addition, PPT using an algesiometer as well as tissue t-Hb and StO 2 using NIRS were measured 21) .…”

Muscle Contraction and Relaxation Described by Tactile Stiffness

“…The principle and applications of our tactile sensor were described previously (5,7–12). The probe of the tactile sensor is 55 mm in length, 7 mm in diameter, and 2.4 g in weight.…”

“…Fast‐twitch and slow‐twitch muscles differ in fatigue resistance, histology (3), and their time courses of contraction and relaxation (4), and the degree of LDM transformation can be evaluated by examining these features. We have described a new method of measuring the tactile stiffness of LDM using our tactile sensor system in a previous report (5). In that study, we monitored change in tactile stiffness for 45 min and detected fatigue of LDM, especially in situ.…”

“…In that study, we monitored change in tactile stiffness for 45 min and detected fatigue of LDM, especially in situ. Comparing the fatigue of conditioned and unconditioned LDMs monitored by our tactile method with histological studies, we concluded that LDM transformation from Type II fiber to Type I fiber can be evaluated by monitoring the tactile stiffness instead of measuring muscle tension (5). Examining the time course of muscle contraction and relaxation is another way of evaluating LDM transformation (6).…”