Associations between Muscle-Tendon Morphology and Functional Movements Capacity, Flexibility, and Balance in Older Women

Age and sex-related differences in elastic properties of the gastrocnemius muscle-tendon unit: an observational prospective study

Introduction

Changes in the mechanical properties of the gastrocnemius muscle-tendon unit can lead to abnormal biomechanics of lower limbs, which is a risk factor for the development of many diseases. However, fewer studies have explored physiological changes in the gastrocnemius muscle-tendon unit stiffness. This study aimed to investigate the age- and sex-related differences in the gastrocnemius muscle-tendon unit stiffness.

Methods

The study included 20 older women, 20 young women, and 20 older men. Shear wave elastography (SWE) was used to measure the stiffness of the medial gastrocnemius (MG), lateral gastrocnemius (LG), and Achilles tendon (AT) in all subjects in relaxed, neutral, and standing positions.

Results

The results showed no significant differences in the MG, LG, and AT stiffness between the dominant and non-dominant sides (p > 0.05). The MG, LG, and AT stiffness changed with positions (p < 0.05). The LG stiffness in older women was lower than in older men and young women in any position (p < 0.05). The MG stiffness in older men was greater than that in older women in any position, and age-related changes were found only in the relaxed and standing positions (p < 0.05). The AT stiffness was higher in older men only in the relaxed position (p < 0.05). There was no significant difference in AT stiffness between older and younger women at any position (p > 0.05).

Discussion

These results suggest that the bilateral gastrocnemius muscle-tendon unit stiffnesses were similar regardless of sex, age, and position. The stiffness of the gastrocnemius in women decreased with age. However, the effect of aging on AT stiffness was slight. Men have greater gastrocnemius stiffness in older adults.

Exploring the relationship between ultrasound parameters and muscle strength in older adults: a meta-analysis of sarcopenia-related exercise performance

Introduction

Ultrasound (US) imaging has emerged as a promising tool for assessing age-related muscle changes. This meta-analysis aimed to comprehensively evaluate the associations between US parameters and muscle strength, as well as sarcopenia-related functional performance in older adults by integrating data from multiple studies.

Methods

A systematic literature search was conducted in PubMed, Web of Science, and Embase until June 2023. Studies reporting Pearson's correlation coefficients between US parameters [echo intensity (EI), muscle thickness (MT), cross-sectional area (CSA), pinnations angle (PA), fascicle length (FL)] and measures of muscle strength or physical performance in older adults were included. Effect sizes were pooled using a random-effects model and presented in forest plots. Heterogeneity was assessed using I 2, and publication bias was evaluated using Egger's test.

Results

Twenty-eight studies met the inclusion criteria. Meta-analysis revealed moderate to strong correlations between EI, MT, and CSA with muscle strength. However, no significant associations were found between US parameters and gait speed. For chair stand tests, the strength of associations varied by test type, with weak correlations observed between echo intensity and muscle thickness with sit-to-stand tests. US parameters did not exhibit significant correlations with the Timed Up and Go test.

Conclusion

Ultrasonographic measurements of echo intensity (EI) and muscle thickness (MT) demonstrated moderate to strong correlations with muscle strength and functional assessments related to sarcopenia. To enhance the accuracy of sarcopenia diagnosis and the effectiveness of management strategies, there is a need for larger, longitudinal studies that evaluate a comprehensive range of ultrasonographic parameters.

Systematic review registration

https://inplasy.com, identifier INPLASY202410086.

The effects of 6-week home-based static stretching, dynamic stretching, or eccentric exercise interventions on muscle-tendon properties and functional performance in older women

Background

Joint inflexibility is acknowledged as a significant contributor to functional limitations in the older adult, with lengthening-type exercises identified as a potential remedial approach. Nevertheless, the responses to eccentric exercise in female older adults have not been extensively studied especially in home-based environment. Here, we aimed to assess the effectiveness of home-based static stretching (ST), dynamic closed-chain stretching (DCS), or eccentric exercise (ECC) interventions on flexibility, musculotendinous architecture, and functional ability in healthy older women.

Methods

We randomly assigned 51 healthy older women (age 65.9 ± 3.4 years) to one of three interventional exercise groups: DCS (N = 17), ECC (N = 17), or ST (N = 17). The training was performed 3 times a week for 6 weeks. The participants' musculotendinous stiffness, fascicle length, eccentric strength, and functional capacities were measured before the intervention, after 6 weeks of exercise, and at a 1-month follow-up.

Results

The results showed that all three interventions improved hamstring flexibility and passive ankle dorsiflexion (p < 0.001), with increased biceps femoris and medial gastrocnemius fascicle length (p < 0.01). However, there was no significant change in musculotendinous stiffness. The ECC intervention produced a greater improvement in knee flexor and calf eccentric peak torque (p < 0.05), and gait speed (p = 0.024) than the other two interventions. The changes in flexibility and knee flexor strength remained for up to 4 weeks after detraining.

Conclusion

In conclusion, the present study suggests that home-based ECC may be more beneficial in enhancing physical capacities in older women compared with either DCS or SS interventions.