Achilles tendon

Previous research suggests that the moment arm of the m. triceps surae tendon (i.e., Achilles tendon), is positively correlated with the energetic cost of running. This relationship is derived from a model which predicts that shorter ankle moment arms place larger loads on the Achilles tendon, which should result in a greater amount of elastic energy storage and return. However, previous research has not empirically tested this assumed relationship. We test this hypothesis using an inverse dynamics approach in human subjects (n = 24) at speeds ranging from walking to sprinting. The spring function of the Achilles tendon was evaluated using specific net work, a metric of mechanical energy production versus absorption at a limb joint. We also combined kinematic and morphological data to directly estimate tendon stress and elastic energy storage. We find that moment arm length significantly determines the spring-like behavior of the Achilles tendon, as well as estimates of mass-specific tendon stress and elastic energy storage at running and sprinting speeds. Our results provide support for the relationship between short Achilles tendon moment arms and increased elastic energy storage, providing an empirical mechanical rationale for previous studies demonstrating a relationship between calcaneal length and running economy. We also demonstrate that speed and kinematics moderate tendon performance, suggesting a complex relationship between lower limb geometry and foot strike pattern. The role of the Achilles tendon (AT) in elastic energy storage with subsequent return during stance phase is well established 1-7. Recovery of elastic energy imparted to the AT is potentially influenced by AT morphology in three ways: (1) material properties of the tendon, (2) cross-sectional area of the tendon, and (3) the moment arm of the calcaneal tuberosity loading the tendon against the muscle force of the m. triceps surae (i.e., foot geometry). Previous work suggests that foot geometry may explain variation in how much potential energy is stored in the tendon, finding that a shorter AT moment arm is correlated with lower mass-specific energy costs of locomotion (COL; L O 2 kg −1 s −1) 8, 9. This finding suggests that shorter AT moment arms are associated with greater elastic loads imparted to the tendon, which are then recovered as kinetic energy during the support phase of each gait cycle 9 , thereby reducing COL. Scholz et al. 9 also suggest that the length of the AT moment arm is a more significant factor in explaining COL than variation in material properties of the tendon itself or size-related variation in the cost of swinging the leg forward during the aerial phase of the gait cycle 9. However, assumptions about the interacting roles of AT moment arm length, tendon cross-sectional dimensions, and tendon material properties on variation in elastic energy storage have yet to tested in an integrated manner. Moreover, Scholz et al. 9 doesn't directly measure the variables in the model which predict variation in elastic energy storage, including muscle force and the external moment arm. Finally, because previous studies of how AT moment arm length influences COL have used trained runners running on a treadmill at a speed of 16 km/h, it is still unknown how variation in speed and athletic training impacts elastic loading to the tendon in relation to moment arm length. While previous work has explored elastic loading of the AT at different speeds and under different loading conditions 10-21 , this study is the first to investigate the potential correlation between foot geometry like the AT moment arm length and spring-like behavior of this tendon in humans. In this study, we model elastic loading of the AT by characterizing the spring-like behavior over the support phase of each gait cycle using two metrics. First, we calculate specific net work (SNW) at the ankle joint. SNW is OPEN

Deficits in ankle muscle strength and ankle stiffness may be present in those subjects who underwent surgical treatment for an Achilles tendon rupture. The presence of these long-term deficits may contribute to a lower performance during daily activities and may be linked to future injuries. To compare the ankle passive stiffness and the plantar flexor muscle performance in patients who underwent unilateral surgical treatment of Achilles tendon rupture with nonsurgical subjects. Twenty patients who underwent unilateral surgical treatment of Achilles tendon rupture [surgical (SU) group], and twenty nonsurgical subjects [non-surgical (NS) group] participated in this study. The ankle passive stiffness was evaluated using a clinical test. The concentric and eccentric plantar flexors performance (i.e. peak torque and work) was evaluated using an isokinetic dynamometer at 30°/s. The surgical ankle of the surgical group presented lower stiffness compared to the non-surgical ankle (mean dif...

Studies regarding ankle and foot overuse injuries are quite diverse in research methodology, data reporting, and outcomes. The aims of this systematic review were to analyze the methodology of published studies regarding ankle and foot overuse injuries in different sports disciplines and to summarize epidemiological data of ankle and foot overuse injuries. Four electronic databases, PubMed (MEDLINE), EMBASE, CINAHL, and SPORTDiscus(®) were systematically searched up to June 2011. A total of 89 articles on 23 sports disciplines were included in this review. Soccer, running, and gymnastics were the most frequently studied sports. Achilles tendinopathy, plantar fasciitis, and stress fracture were the most frequently studied injuries. Study design and reporting methods were heterogeneous. Most studies suffered from a weak methodology and poor reporting. The most common weaknesses were lack of a clear case definition, describing assessment procedures and reporting sample characteristics....

The etiology, pathogenesis and natural course of Achilles tendinopathy are not yet completely known. Various forms of therapies, either conservative or surgical, have been proposed for its treatment. In the last few years, extracorporeal shockwave therapy (ESWT) has been proposed in the treatment of these tendinopathies and has shown encouraging short-term results. The purpose of this type-C study was to evaluate the effectiveness of ESWT in the symptomatic treatment of Achilles tendinopathies over time. One hundred five patients (127 tendons) aged between 18 and 74 years (mean age 47.8) were enrolled in this study. All patients underwent clinical and instrumental diagnosis (ultrasonography, magnetic resonance imaging and X-rays) in order to identify presence, location and seriousness of the specific tendinopathy. The symptomatology was classified using the Visual Analogical Scale (VAS) and according to a five-stage clinical evaluation range. Shock wave treatment was applied with an...

Questa tesi propone un commento e un'introduzione all'episodio della morte di Achille, così come è narrato da Quinto Smirneo nei primi 185 versi del terzo logos dei Posthomerica. Il commento analizza questioni lessicali e tematiche, che mettono in luce il modo in cui lo scrittore del III secolo d.C. si confronta e rielabora i miti e la dizione epica della tradizione. Si mettono così in evidenza le differenze tra le specifiche strategie compositive del poeta letterato rispetto alle forme della composizione orale. Tramite l'analisi delle fonti letterarie e iconografiche, nell'introduzione vengono esaminate le varianti mitologiche della morte di Achille, i miti circa la sua immortalità o invulnerabilità, l'importanza dell'arma con cui Apollo ferisce l'aristeuon acheo, e il modo in cui l'attacco di Apollo costituisce un totale ribaltamento degli schemi epici del duello.

Movement is fundamental to human well-being, function and participation in work and leisure activities. As a result, regaining optimal movement abilities and independence frequently become central foci of rehabilitation programs developed for individuals recovering from serious orthopedic and neurologic injuries. Further, preventing additional injury to the locomotor system becomes essential for effective long-term management of chronic medical conditions such as tendon dysfunction and diabetes. The primary aim of this perspective is to illustrate the role of biomechanics in orthopedics, musculoskeletal and neurological rehabilitation. Specifically, this paper discusses selected examples, ranging from the tissue to whole body biomechanics level, that highlight how scientific evidence from the theoretical and applied sciences have merged to address common and sometimes unique clinical problems.

This article discusses the treatment of soft tissue injuries in the ankle and foot, including rupture of the Achilles tendon, Achilles tendonitis, peroneal tendonitis, peroneal tendon syndromes, and ankle sprain. It also discusses the causes, treatment, and reconstruction of soft tissue defects in the foot.

Two fractions showing proteolytic enzymes have been obtained from the latex of Synadenium grantii Hook, ‘f’, using gel-filtration and anion-exchange chromatographic techniques. Both these proteases have the same molecular mass of 76±2 kDa each. They exhibit maximal activity at pH 7.0 and at a temperature of 60 °C. They display stability over a pH range from 5–10 and are also highly thermostable. Irreversible inhibition by PMSF indicates that they are serine proteases. In addition, histidine residues also appear to play an important role in catalysis as evidenced by inhibition with DEPC. They also exhibit similarity with respect to pH and temperature optima, kinetic properties and thermal stability.

The effect of pelvic and Achilles tendon suspension of red and fallow deer carcasses on meat quality parameters were compared. Venison was evaluated from red deer stags (n=14), bucks (n=14) and fallow deer does (n=10) between 12 and 36months old. Immediately after slaughter, carcasses were split down the dorsal midline and assigned to one of the two hanging methods and pH and core body temperature measured. Twenty-four hours post-slaughter muscles were excised. Venison from fallow deer and red deer stags pelvic-suspended had significantly lower (P<0.001) cooked shear force values than Achilles hung carcasses. There was no significant difference between hanging technique for other characteristics measured. These data indicated that pelvic suspension should be adopted by the deer industry to increase tenderness of venison.

Aim of this study is to compare the different kinds of tendonitis in athletes using cryoultrasound therapy, lasertherapy CO2 and t.e.ca.r. therapy (transfert energetic capacitive and resistive). Forty five athletes were selected; they were all affected by severe insertional tendonitis of the Achilles tendon (15 of them), of the patellar tendon (15 of them) and of the epicondylar region (15 of them) during the last two months. They were divided into three groups. The first group underwent a treatment of 12 lasertherapy CO2 sessions, the second group 12 cryoultrasound therapy sessions and the last group 12 t.e.ca.r. therapy sessions. Each patient was registered by an independent observer according to the pain before (initial V.A.S.) and after treatment (final V.A.S.) using the analogic visual range from 0 (lack of pain) to 10 (unbearable pain) and the indicator of efficacy (difference between initial V.A.S. and final V.A.S./initial V.A.S.x 100). The obtained results were expressed as ...