ACHILLES - New methods to study Achilles tendon structure and loading
Table of contents
Project description
Achilles tendon is an important tissue in locomotion, but human research lacks clinically relevant evidence of tendon structure–function relationships. Animal and cadaver studies have revealed the complex structure of the Achilles tendon (AT) with three subtendons, which is likely a key for understanding individual differences in the function of healthy and pathological tendons. ACHILLES first develops a USTIM-method for mapping the three-dimensional structure of the AT and its three subtendons in vivo, using ultrasonography, kinematics, electrical stimulation and computational modeling. Human experiments are intertwined with modeling of AT subtendons using our newly developed continuum finite beam elements for beam-like soft tissue structures. The experimental data feeds the models that are used to find factors predisposing AT to high regional strains and stresses. Ultimately, ACHILLES produces a REHAB-TRAINING tool to address the need for individualized treatments that can be used to guide rehabilitation. ACHILLES bridges the current gap between in vivo human and cadaver/animal
studies in the area of muscle-tendon tissue biomechanics and advances understanding of human AT structure function relationships with the novel tools.
Current information
ACHILLES-seminar was held on 12.12.2024 We had over 200 participants world-wide. Seminar introduction by Taija Juutinen Finni:
Participants are still being actively recruited and all enquiries are welcome at achilles-projekti@jyu.fi. If participation in laboratory measurements is not possible, surveys can be completed from the comfort of your own home computer. Laboratory measurements will resume February 17th 2025.
Volunteer for student helper or intern (unpaid) and gain experience in lab measurements! Contact Taija.m.juutinen@jyu.fi for information.
Volunteer for research participant
We are looking for healthy adults aged 18-55 with any of the following.
- Healthy Achilles tendons
- Tendinopathy/tendon pain of the Achilles tendon (not at the insertion site to calcaneus)
- Achilles tendon rupture within 5 years
In addition, to participate in the research, you must not have.
- General diseases affecting tendon health (e.g. diabetes)
- Tendon cortisone injections in the previous 12 months
- Other injuries affecting to locomotion
The research will include several components: a USTIM study, magnetic resonance imaging of the leg, tendon force measurements, and functional measurements. You can participate in one or more of these parts.
The first part of the research: USTIM (all participants)
USTIM uses ultrasound, motion analysis and electrical stimulation to examine the structure of the Achilles tendon. The examination also includes a body composition measurement with a bioimpedance device. Participants will get the analysis of the body composition measument for themselves.
The measurement is performed in the prone position, where the Achilles tendon is imaged with ultrasound in different positions of the ankle joint. At the same time, the calf muscles are electrically stimulated from the surface of the skin at three different points in turn. The electrical stimulation is performed at very low intensity in short bursts of about one second. This is followed by ultrasound imaging of the tendon during ankle extension in the sitting position with the knee straight and the knee bent.
In USTIM measurements the participant is lying on her stomach while the Achilles tendon is being imaged with ultrasound.
Magnetic resonance imaging (selected participants)
As part of the USTIM examination, magnetic images of the leg can also be taken to represent the structure of the Achilles tendon. If you have a pacemaker or metal in the leg being imaged, magnetic images will not be taken.
Functional measurements (tendinopathic and rupture participants)
In functional measurements, EMG electrodes are placed on the skin of the legs to measure the electrical activity of the muscles along with reflective markers for motion imaging. At the same time, the Achilles tendon is imaged using ultrasound. During the measurements, the subject will be asked to walk, perform heel raises and drops in a seated and standing position on both one and two legs, do bilateral squats, and jumps. If you have a tension injury, you will only do as much as you can safely do in normal life. The purpose of the measurements is to determine the function and load on the tendon during different movements.
In functional measurements reflective markers are placed on several points on the skin of legs and hips.
Tendon force measurements (start in November)
In tendon force measurements, a device is attached around the ankle to measure the strength of the Achilles tendon from the skin surface. The rest of the measurement is similar to the functional measurements described above, where the subject is asked to run, walk, jump, and perform various rehabilitation exercises. In addition, the subject is asked to extend the ankle while seated on the force-measuring device. In the same position, the calf muscles are also electrically stimulated from the skin surface to produce a gentle ankle extension.
Questionnaire validation study
You will be asked to take part in the questionnaire validation study if you have tendinopathy/tendon pain of the Achilles tendon (not at the insertion site to calcaneus) or if you have had an Achilles tendon rupture within 5 years. If you have healthy Achilles tendons, you do not need to complete the questionnaire. The form is filled in at the first study visit and will be sent to you digitally to be filled in again approximately 1-2 weeks later. If you do not participate in the other parts of the study, the forms will be sent to you digitally both times and we will ask you questions about your basic information and tendon injury history.
Why participate in the research?
The study will give information about the function and structure of your Achilles tendon, ultrasound images of your tendon and an analysis of your body composition measurement. You will also be involved in the development of important research on tendon health that can be used to develop rehabilitation methods for Achilles tendon injuries.
Other points to note
Participating in the study takes some time. In addition, the long duration of the USTIM measurement while lying still on your stomach, the equipments placed on the skin and the electrical stimulation may cause discomfort. In rare cases, the electrical stimulation may cause nausea due to an autonomic nervous system reaction. If this happens, or if at any stage of the study subject shows a desire to stop, the measurements will be stopped. No specific reason needs to be given and there are no consequences for the subject for quitting.
Contacts and research notifications
If you are interested, please contact the researchers, preferably by email:
Telephone numbers of researchers:
Professor Taija Juutinen 040-5566582
PhD Researcher Maria Sukanen 050-5363233
PhD Researcher Afet Mustafaoglu (in English) 050-4393930
MSc Student Jeremias Malinen 045-2085749
