At matched loads, aging does not alter ankle, muscle, or tendon stiffness

Older adults have difficulty maintaining balance when faced with postural disturbances, a task that is influenced by the stiffness of the triceps surae and Achilles tendon. Age-related changes in Achilles tendon stiffness have been reported at matched levels of effort, but measures typically have not been made at matched loads, which is important due to age-dependent changes in strength. Moreover, there has been limited investigation into age-dependent changes in muscle stiffness. Here, we investigate how age alters muscle and tendon stiffness and their influence on ankle stiffness. We hypothesized that age-related changes in muscle and tendon contribute to reduced ankle stiffness in older adults and evaluated this hypothesis when either load or effort were matched. We used B-mode ultrasound with joint-level perturbations to quantify ankle, muscle, and tendon stiffness across a range of loads and efforts in seventeen healthy younger and older adults. At matched loads relevant to standin..., , , # Aging ankle, muscle, tendon stiffness

[https://doi.org/10.5061/dryad.k98sf7mfx](https://doi.org/10.5061/dryad.k98sf7mfx)

## Description of the data and file structure

The data includes all the estimates of ankle, muscle, and tendon stiffness for all participants, as well as their plantarflexion torque and muscle activations (medial gastrocnemius MG, lateral gastrocnemius LG, soleus, and tibialis anterior TA. 

There is also the subject information (age group, sex, max torque, fall risk, and CHAMPS score). Fall risk and CHAMPS were not collected for young adults, and thus the values are NaN. Young adults (YA) are between 18-35 years old while older adults (OA) are older than 60 years.Â