Abstract details
| Abstract-ID: | 1942 |
| Title of the paper: | Effect of dynamic stretching on the shear modulus of the biceps femoris long head |
| Authors: | Sakamoto, R., Nakamura, M., Itaya, S., Sugano, J., Yanase, K. |
| Institution: | Doshisha University |
| Department: | Faculty of Health and Sports Science |
| Country: | Japan |
| Abstract text | INTRODUCTION: In sports settings, dynamic stretching (DS) is used to prevent injury and enhance sports performance. Many previous studies reported that the joint range of motion (ROM) increases immediately after DS (1, 2). Muscle stiffness is one of the elements constituting the ROM; however, as far as we know, it is unclear whether DS affects muscle stiffness. The purpose of this study was to determine the changes in muscle shear modulus following DS. METHODS: The participants comprised 13 healthy young men (20.9 ± 1.8 years, 172.3 ± 4.8 cm, 65.9 ± 8.9 kg). They performed DS of right hip flexors in the supine position, completing 8 sets of 30-second with 60 seconds rest interval. The shear moduli of the biceps femoris long head (BFlh) were measured before DS, after 4 sets of DS (4DS), and after 8 sets of DS (8DS) using ultrasonic shear wave elastography. In addition, ROMs were measured before DS and after 8DS using Biodex, and the initial position was the hip flexed at 120° and knee flexed at 90° in a supine position. The ROM was defined as the maximum angle achieved by movement of only knee extension. A one-way repeated measures analysis of variance (ANOVA) and Bonferroni’s post hoc test were used to determine the effects of DS on the shear modulus of the BFlh, and a paired t-test was used to determine the effect of DS on ROM. RESULTS: The ANOVA showed the main effect of time and Bonferroni’s post hoc tests showed that the shear moduli after 4DS (36.9 ± 16.6 kPa) and 8DS (36.1 ± 11.6 kPa) were significantly higher than before DS (31.2 ± 15.2 kPa) (both p < 0.01). On the other hand, there was no significant difference in shear modulus after 4DS and after 8DS (p = 1.00). The ROM was significantly higher after 8DS than before DS (p = 0.02). CONCLUSION: Our results suggest the DS of hip flexors increases the shear modulus of the BFlh. On the other hand, the DS of that increased ROM. Further research is needed to examine the mechanism by that DS increases muscle stiffness while simultaneously increasing ROM. References (1) Iwata et al., J Sports Sci Med, 2019 (2) Matsuo et al, J Sports Sci Med. 2023 Contact cgtg0146@mail4.doshisha.ac.jp |
| Topic: | Health and Fitness |
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