Influence of calcaneus angle and muscle forces on strain distribution in the human Achilles tendon

NewsBot · Aug 14, 2012

Members do not see these Ads. Sign Up.
Influence of calcaneus angle and muscle forces on strain distribution in the human Achilles tendon.
Lersch C, Grötsch A, Segesser B, Koebke J, Brüggemann GP, Potthast W.
Clin Biomech (Bristol, Avon). 2012 Aug 7

BACKGROUND:
Heterogeneous distribution of tendon strain is considered to contribute to the development of the Achilles tendon overuse injuries. Force distribution between the three portions of the triceps surae muscle and position of the calcaneus might affect the extent of strain differences within the Achilles tendon. Purpose of this study was to determine the effect of changes in force distribution within the triceps muscle and changes in calcaneus position on intratendinous strain distribution of the Achilles tendon.

METHODS:
Five cadaveric Achilles tendons including complete triceps surae and calcaneus were dissected. Specimens were mounted in a loading simulator allowing independent force application for the three parts of triceps muscle and changes calcaneus eversion and inversion position. Strain was determined in different aspects of the Achilles tendon.

FINDINGS:
Changes of calcaneus position resulted in intratendinous strain differences up to 15%, changes in force distribution within the triceps muscle resulted in strain differences up to 2.5%. Calcaneal eversion was connected to a higher degree of strain in medial tendon portions, while inversion increased strain in lateral tendon portions.

INTERPRETATION:
Medio-lateral, proximo-distal and dorsal-ventral distribution of tendon strain is rather influenced by kinematics of the subtalar joint than by muscular imbalances within the triceps muscle. Clinical movement analyses should focus on motion pattern combining rearfoot eversion with high Achilles tendon load. The results indicate that twist of the Achilles tendon fascicles seems of paramount importance in balancing tendon strain. To get more insight into the Achilles tendon injuries pathogenesis future research should focus on methods monitoring heterogeneous distribution of strain in vivo.
Click to expand...

Admin2 · Aug 14, 2012

Related threads:
Other threads tagged with achilles tendon
Other threads tagged with overuse injury
Variability of the Achilles Tendon Insertion
Uphill running improves achilles tendon mechanical properties
STJ Axis Variations and Achilles Tendonitis
Biochemical changes in achilles tendinosis
Genetic component to achilles tendon pathology
Biomechanics and achilles tendonitis
Achilles Tendinopathy Has an Aberrant Strain Response to Eccentric Exercise
Is compressive load a factor in the development of tendinopathy?
The plantaris tendon and a potential role in mid-portion Achilles tendinopathy
Evolution of the Achilles tendon
Mechanical Properties of the Achilles Tendon Aponeurosis Are Altered in Athletes With Achilles Tendinopathy

NewsBot · Sep 1, 2014

The contraction-induced increase in Achilles tendon moment arm: A three-dimensional study
Satoru Hashizume, Soichiro Iwanuma, Ryota Akagi, Hiroaki Kanehisa, Yasuo Kawakami, Toshimasa Yanai
Journal of Biomechanics Articles in Press

The present study aimed to re-examine the influence of the isometric plantarflexors contraction on the Achilles tendon moment arm (ATMA) and the factors influencing the ATMA in three-dimensions. A series of coronal magnetic resonance images of the right ankle were recorded at foot positions of 10° of dorsiflexion, neutral position, and 10° of plantarflexion for the rest condition and the plantarflexors contraction condition at 30% maximal voluntary effort. The shortest distance between the talocrural joint axis and the line of action of the Achilles tendon force projected to the orthogonal plane of the talocrural joint axis was determined as the ATMA. The ATMA determined in the contraction condition was significantly greater by 8 mm than that determined in the rest condition. The talocrural joint axis was displaced anteriorly by 3 mm and distally by 2 mm due to the muscle contraction. As the same time, the line of action of the Achilles tendon force was displaced posteriorly by 5 mm and medially by 2 mm. These linear displacements of the talocrural joint axis and the line of action of the Achilles tendon force accounted for the difference in the ATMAs between the two conditions by 35.9 and 62.4%, respectively. These angular displacements accounted for the total of 0.4% increase in the ATMA. These results confirm the previous findings reported in two-dimensional studies and found that the linear displacement of the line of action of the Achilles tendon force is the primary source of the contraction-induced increase in the ATMA.
Click to expand...

NewsBot · Sep 20, 2016

Differences in the degree of stretching applied to Achilles tendon fibers when the calcaneus is pronated or supinated
Mutsuaki Edama et al
The Foot and Ankle Online Journal 9 (3): 5

Purpose: The purpose of the present study was to examine the degree of stretching (%) that is applied to each of the tendon fiber bundles that compose the Achilles tendon (AT) by twist type when the calcaneus is pronated or supinated.

Methods: Three AT twist types (least, moderate, extreme twists), one for each type were investigated. Using the MicroScribe system, the AT and the calcaneal tuberosity were digitized to reconstruct three-dimensional models. Using this system, the calcaneus rotations in the pronation (20°) and supination (20°) directions were simulated, and the degrees of stretching (%) of each tendon were calculated.

Results: For all twist types, when the calcaneus was pronated, the medial head of the gastrocnemius (MG) and lateral head of the gastrocnemius (LG) shortened and the soleus muscle (Sol) stretched, and when supinated, MG and LG stretched and Sol shortened. In particular, severe twist type had the largest degree of stretching of Sol when the calcaneus was pronated (Type I: 1.7% ± 3.4%, Type II: 2.4% ± 1.4%, Type III: 3.7% ± 6.0%), and furthermore, each tendon fiber composing Sol had different degrees of stretching.

Conclusions: The study results suggest that the degree of stretching applied within the AT with calcaneus pronation is not constant, and that, especially in Type III twists, the risk of developing AT disorders may increase.
Click to expand...

NewsBot The Admin that posts the news.

Admin2 Administrator Staff Member

NewsBot The Admin that posts the news.

NewsBot The Admin that posts the news.

Diabetic Foot Influencers on Twitter

Muscular Systems and Their Influence on Foot Arches

Influence of Cognitive Performance on Musculoskeletal Injury Risk

The Influence of Pain and Resiliency on Foot and Ankle Surgery Outcomes

Motivations, sources of influence and barriers to being a podiatrist

Influence of a novel elastic foot orthosis in foot motion with mild flat foot

Foot Sole Cutaneous Sensitivity is Influenced by Foot Posture

Share This Page