Assessments of Mechanical Stiffness and Relationships to Performance Determinants in Middle-Distance Runners

Purpose: To examine relationships between methods of lower-limb stiffness and their associations with running economy (RE) and maximal velocity (vmax) in middle-distance (MD) runners. Methods: Eleven highly trained male MD runners performed a series of mechanical and physiological tests to determine maximal overground sprint speed, RE, and . Achilles tendon stiffness (kT) was estimated using ultrasonography during maximal isometric ankle plantar flexion. Global stiffness qualities were evaluated using a spring-mass model, providing measures of leg (kleg) and vertical stiffness (kvert) during running and jumping, respectively. Results: Very large (r = −.70) and large (r = −.60) negative relationships existed between RE and kT and kvert, during plantar flexion and unilateral jumps, respectively. There were large (r = .63) and extremely large (r = −.92) associations between kvert and kT and kleg during sprinting, respectively. Runners’ vmax had large positive associations between kT (r = .52) and kleg (r = .59) during sprinting. Conclusions: In well-trained MD athletes, greater stiffness appears linked to faster and more economical running. Although kT had the strongest relationship with RE, kleg while sprinting and kvert in maximal unilateral jumps may be more practical measures of stiffness. Agreement between global stiffness assessments and kT highlights the energy contribution of the Achilles tendon to running efficiency and velocity. Further research incorporating these assessment tools could help establish more comprehensive mechanical and metabolic athlete profiles and further our understanding of training adaptations, especially stiffness modification, longitudinally.

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Muscular Morphomechanical Characteristics After an Achilles Repair

Foot & Ankle International ◽

10.1177/1071100718822537 ◽

2019 ◽

Vol 40 (5) ◽

pp. 568-577 ◽

Cited By ~ 5

Author(s):

Wei-Chen Peng ◽

Yuan-Hung Chao ◽

Amy S. N. Fu ◽

Shirley S. M. Fong ◽

Christer Rolf ◽

...

Keyword(s):

Achilles Tendon ◽

Plantar Flexion ◽

Tendon Repair ◽

Morphological Characteristics ◽

Muscle Length ◽

Medial Gastrocnemius ◽

Mechanical Stiffness ◽

Level Of Evidence ◽

Fascicle Length ◽

Fascicle Angle

Background: The purpose of the study was to compare the morphomechanical and functional characteristics during maximal isometric, concentric, and eccentric contractions in the legs of patients that underwent unilateral Achilles tendon repair with those in their noninjured control legs. Methods: Twenty participants (median age = 38.2 years; range, 21.1-57.3 years) who underwent Achilles repair between 3 and 12 months ago were recruited with the following measures: (1) mechanical stiffness of the aponeurosis and (2) electromyography and medial gastrocnemius fascicle angle and length, standing muscle and tendon length, and height of heel rise with isometric contraction. Results: Compared to the noninjured legs, the repaired legs showed less resting fascicle length, standing muscle length, isometric plantarflexion torque, and heel raise distance ( Ps ranged between .044 and <.001). During the concentric and eccentric phases of the raising and lowering test, the repaired legs demonstrated less fascicle length ( P ≤ .028) but greater tendinous tissue length ( Ps ranged between .084 and <.001) and fascicle angle ( Ps ranged between .247 and .008) and fewer change magnitudes of the fascicle length and tendinous tissue length ( P ≤ .003). The change magnitudes of the morphological characteristics showed correlations with the torque or distance. Conclusion: Selecting the appropriate surgical repair and rehabilitation for Achilles tendon ruptures is recommended for restoring the length and mechanical strength of the muscle-tendon unit of plantar-flexion muscles. Level of Evidence: Level III, comparative study.

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Operative Outcome of Side-Locking Loop Suture Technique Accompanied by Autologous Semitendinosus Tendon Grafting for Chronic Rupture of Achilles Tendon

Foot & Ankle Orthopaedics ◽

10.1177/24730114211003541 ◽

2021 ◽

Vol 6 (2) ◽

pp. 247301142110035

Author(s):

Keisuke Tsukada ◽

Youichi Yasui ◽

Maya Kubo ◽

Shinya Miki ◽

Kentaro Matsui ◽

...

Keyword(s):

Achilles Tendon ◽

Scale Score ◽

Tendon Rupture ◽

Plantar Flexion ◽

Achilles Tendon Rupture ◽

Case Series ◽

Semitendinosus Tendon ◽

Level Of Evidence ◽

Operative Outcomes

Background: The purpose of this retrospective study was to clarify the operative outcomes of the side-locking loop suture (SLLS) technique accompanied by autologous semitendinosus tendon grafting for chronic Achilles tendon rupture. Methods: A chart review was conducted of consecutive patients treated with the SLLS technique at our department from 2012 to 2017. Postoperatively, a below-knee splint was applied for 2 weeks in 20 degrees of plantar flexion and then active range of motion exercise was started. Partial weightbearing exercise was allowed at 4 weeks according to patient tolerance, and full weightbearing without crutches was allowed at 8 weeks. The American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale score and the Achilles tendon rupture score (ATRS) were used to evaluate clinical outcomes preoperatively and at the final follow-up. Results: Ten patients (6 men, 4 women) were included in the analysis. Mean AOFAS ankle-hindfoot scale score increased significantly from 64.2 ± 5.6 points preoperatively to 95.0 ± 5.3 points at the final follow-up ( P < .001). The mean ATRS also increased significantly from 29.8 ± 4.4 points to 86.2 ± 7.7 points, respectively ( P < .001). Mean time between surgery and ability to perform 20 continuous double-leg heel raises of the operated foot was 13.5 ± 3.4 (range 10-18) weeks. One patient complained of postoperative hypoesthesia in the foot, which had spontaneously resolved by 3 months after surgery. Conclusion: The SLLS technique accompanied by autologous semitendinosus tendon grafting provided successful operative outcomes for patients with chronic Achilles tendon rupture regardless of the size of the defect, and thus long-term orthotic use was not needed after surgery. Level of Evidence: Level IV, retrospective case series.

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Gender Difference in Architectural and Mechanical Properties of Medial Gastrocnemius–Achilles Tendon Unit In Vivo

Life ◽

10.3390/life11060569 ◽

2021 ◽

Vol 11 (6) ◽

pp. 569

Author(s):

Liqin Deng ◽

Xini Zhang ◽

Songlin Xiao ◽

Baofeng Wang ◽

Weijie Fu

Keyword(s):

Mechanical Properties ◽

Gender Differences ◽

Gender Difference ◽

Achilles Tendon ◽

Medial Gastrocnemius ◽

Regular Exercise ◽

Training Experience ◽

Exercise Habits ◽

Vertical Stiffness

This study aims to explore whether gender differences exist in the architectural and mechanical properties of the medial gastrocnemius–Achilles tendon unit (gMTU) in vivo. Thirty-six healthy male and female adults without training experience and regular exercise habits were recruited. The architectural and mechanical properties of the gMTU were measured via an ultrasonography system and MyotonPRO, respectively. Independent t-tests were utilized to quantify the gender difference in the architectural and mechanical properties of the gMTU. In terms of architectural properties, the medial gastrocnemius (MG)’s pennation angle and thickness were greater in males than in females, whereas no substantial gender difference was observed in the MG’s fascicle length; the males possessed Achilles tendons (ATs) with a longer length and a greater cross-sectional area than females. In terms of mechanical properties, the MG’s vertical stiffness was lower and the MG’s logarithmic decrement was greater in females than in males. Both genders had no remarkable difference in the AT’s vertical stiffness and logarithmic decrement. Gender differences of individuals without training experience and regular exercise habits exist in the architectural and mechanical properties of the gMTU in vivo. The MG’s force-producing capacities, ankle torque, mechanical efficiency and peak power were higher in males than in females. The load-resisting capacities of AT were greater and the MG strain was lesser in males than in females. These findings suggest that males have better physical fitness, speed and performance in power-based sports events than females from the perspective of morphology and biomechanics.

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Biomechanics and Exercise

Pediatric Exercise Science ◽

10.1123/pes.2015-0033 ◽

2015 ◽

Vol 27 (1) ◽

pp. 34-38

Author(s):

Thomas D. O’Brien

Keyword(s):

Achilles Tendon ◽

Young’S Modulus ◽

Young's Modulus ◽

Plantar Flexion ◽

Tendon Injury ◽

Time Curve ◽

Tendon Stiffness ◽

Prepubertal Children ◽

Experimental Group ◽

Tendon Properties

Children develop lower levels of muscle force, and at slower rates, than adults. While strength training in children is expected to reduce this differential, a synchronous adaptation in the tendon must be achieved to ensure forces continue to be transmitted to the skeleton with efficiency while minimizing the risk of strainrelated tendon injury. We hypothesized that resistance training (RT) would alter tendon mechanical properties in children concomitantly with changes in force production characteristics. Twenty prepubertal children (8.9 ± 0.3 years) were equally divided into control (nontraining) and experimental (training) groups. The training group completed a 10-week RT intervention consisting of 2-3 sets of 8-15 plantar flexion contractions performed twice weekly on a recumbent calf raise machine. Achilles tendon properties (cross-sectional area, elongation, stress, strain, stiffness and Young’s modulus), electromechanical delay (EMD; time between the onset of muscle activity and force), rate of force development (RFD; slope of the force-time curve) and rate of EMG increase (REI; slope of the EMG-time curve) were measured before and after RT. Tendon stiffness and Young’s modulus increased significantly after RT in the experimental group only (~29% and ~25%, respectively); all other tendon properties were not significantly altered, although there were mean decreases in both peak tendon strain and strain at a given force level (14% and 24%, respectively, n.s) which may have implications for tendon injury risk and muscle fiber mechanics. A ~13% decrease in EMD was found after RT for the experimental group which paralleled the increase in tendon stiffness (r = −0.59), however RFD and REI were unchanged. The present data show that the Achilles tendon adapts to RT in prepubertal children and is paralleled by a change in EMD, although the magnitude of this change did not appear to be sufficient to influence RFD. These findings are of potential importance within the context of the efficiency and execution of movement.

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Comparison of Functional Ability Following Percutaneous and Open Surgical Repairs of Acutely Ruptured Achilles Tendons

Journal of Sport Rehabilitation ◽

10.1123/jsr.2.2.115 ◽

1993 ◽

Vol 2 (2) ◽

pp. 115-127 ◽

Cited By ~ 17

Author(s):

Gregory J. Steele ◽

Rod A. Harter ◽

Arthur J. Ting

Keyword(s):

Achilles Tendon ◽

Open Repair ◽

Plantar Flexion ◽

Secondary Purpose ◽

Percutaneous Repair ◽

Study Results ◽

Male Patients ◽

Flexion Strength ◽

Repair Group ◽

Repair Techniques

The purpose of our study was to evaluate the functional outcomes of two methods of surgical treatment of acute closed raptures of the Achilles tendon, specifically, the primary open repair and the percutaneous repair techniques, utilizing (a) isokinetic plantar flexion strength, (b) midcalf girth, (c) ankle joint proprioception, and (d) ankle range of motion values. As a secondary purpose, the frequency of reruptures and postsurgical complications were compared between techniques. Twenty male patients (mean age, 43.8 ± 9.4 years) who sustained complete, closed ruptures of the Achilles tendon participated in this study. Results of pairedttests revealed significant differences between postsurgical and contralateral normal limbs for 6 of 12 variables. Results of the ANOVAs revealed no significant differences between the open repair group and percutaneous repair group for any of the evaluative parameters. The significant deficits in postoperative isokinetic plantar flexion strength and midcalf girth measurements, irrespective of surgical technique, suggest an incompleteness of rehabilitation or, more likely, the physiological inability to regain these characteristics postoperatively.

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TREATMENT OPTIONS FOR NEGLECTED ACHILLES TENDON RUPTURED: WETHER SPONTANEOUS HEALING IS POSSIBLE?

Traumatology and Orthopedics of Russia ◽

10.21823/2311-2905-2018-24-2-59-69 ◽

2018 ◽

Vol 24 (2) ◽

pp. 59-69

Author(s):

A. P. Sereda

Keyword(s):

Surgical Treatment ◽

Achilles Tendon ◽

Treatment Outcomes ◽

Plantar Flexion ◽

Treatment Options ◽

Tendon Healing ◽

Spontaneous Healing ◽

Minimal Incision ◽

Better Than

The paper considers cases of spontaneous healing of achilles tendon with elongation. In such condition the tendon defect is not palpable, active plantar flexion is preserved and patients are complaining for strength diminution.Purpose— to study features of spontaneous achilles tendon healing with elongation and to analyze the shortening tenoplasty option as a procedure primarily aimed at restoration of strength for gastrocnemius-soleus complex.Material and Methods.The paper presents features and outcomes of surgical treatment of 25 patients who underwent a shortening tenoplasty of various types: crimping (3 patients), Z-type (2 patients), oblique (1 patient) and transverse (19 patients).Results.No re-ruptures or other serious complications were observed in the patients of the present study. Treatment outcomes were evaluated by j. leppilahti scale in 304,7±8,9 days after the procedure. postoperative leppilahti scores were statistically significantly better than prior to surgery — 82,4±5,6 and 62,2±7,7, respectively, (p<0,0001). Conclusion. Shortening tenoplasty can be indicated in cases of spontaneous achilles tendon healing with elongation. at relatively early stages of the injury with rather elastic scars the crimping tenoplasty can be applied. At later stages a resection shortening tenoplasty is recommended through a minimal incision with transverse resection of tendon and removal of scar block.

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Arthroscopically-Asissted Achilles Tendon Repair; Long-Term Results

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967114s00222 ◽

2014 ◽

Vol 2 (11_suppl3) ◽

pp. 2325967114S0022

Author(s):

Akın Turgut ◽

Mert Zeynel Asfuroğlu

Keyword(s):

Achilles Tendon ◽

Range Of Motion ◽

Sural Nerve ◽

Plantar Flexion ◽

Tendon Repair ◽

Long Term Results ◽

Calf Circumference ◽

Achilles Tendon Repair ◽

Arthroscopically Assisted

Objectives: The ruptures of the Achilles tendon (AT) are relatively common. Since there is no consensus on the best method of the repair of the AT; the treatment is determined on the preference of the surgeon and the patient. The study evaluating the cadaveric and short term clinical results done by our clinic in 2002, has shown us that arthroscopically Achilles tendon repair can be good choise in achilles tendon ruptures. Methods: Fortyfour patients who underwent arthroscopically assisted achilles tendon repair during 1997-2011 in Osmangazi University Orthopaedics and Traumatology Department were retrospectively observed. The mean follow-up time was 69,7 months. One of patients had bilateral rupture. The diagnosis was based on loss of plantar flexion strength, palpation of the gap in the tendon, and a positive Thompson test. MRI and USG were used when needed. The ruptures were left-sided in nineteen patients and right-sided in twentysix. The cause of the rupture was recreational sports activity in thirtyeight, fall from height in four, missing a step in a staircase in two. Return the regular activity, ankle range of motion as compared with the opposite side, calf circumference, and ability to walk and stand tiptoe were recorded. All patients were operated on within 2-32 days after the rupture. Thirtysix operations were performed under spinal anesthesia and eight operations were performed under general anesthesia. Tourniquet was always used. Before starting the procedure, the rupture site and location of the gap are marked. Using the common videoarthroscopic instruments, a 70 degrees scope was inserted into the AT through the stab incision made previously, and the torn ends of the tendon were visualized with plantar flexion an extension of the ankle. After the visualization of the torn ends of the tendon and repair by the technique of Ma and Griffith care was focused to contact the ends of the tendon anatomically; then the sutures were knotted. A short leg circular cast with the ankle in slight plantar flexion was applied. American Orthopaedics Foot-Ankle Society (AOFAS) score was used to evaluate the long-term results.. Results: All patients had satisfactory results that no reruptures had occurred. No significant difference in range of motion of the ankle and calf circumference between the opposite sides was observed in any patient. All patients could walk and stand on tiptoe. AOFAS mean score was 94.5 (65-100). The interval from injury to return to regular work and activities was 8-10 weeks. All the patients were able to return back to their activity level before surgery. In three patients temporary sural hypoestesia, in one patient permanent sural hipoestesia and in one patient wound enfection appeared. No sensory deficit was detected in the temporary sural hypoestesia patients after postoperative second year controls. Medical care was supported to the patient with the wound enfection and the enfection was under control in the early stages. Conclusion: In summary; arthroscopically-assisted percutaneous repair of AT appears to overcome some certain problems of open, conservative and percutaneous techniques; but the neurovascular structure damage risk especially the sural nerve remains a potent problem. Accurate knowledge of the anatomy appears to be a solution. Novel percutaneous repairs have been promising to minimize the risk of sural nerve damage.

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Mechanical properties of tendon and aponeurosis of human gastrocnemius muscle in vivo

Journal of Applied Physiology ◽

10.1152/jappl.2001.90.5.1671 ◽

2001 ◽

Vol 90 (5) ◽

pp. 1671-1678 ◽

Cited By ~ 150

Author(s):

Tadashi Muramatsu ◽

Tetsuro Muraoka ◽

Daisuke Takeshita ◽

Yasuo Kawakami ◽

Yuichi Hirano ◽

...

Keyword(s):

Mechanical Properties ◽

Achilles Tendon ◽

Gastrocnemius Muscle ◽

Plantar Flexion ◽

Medial Gastrocnemius ◽

Significant Difference ◽

Functional Implications ◽

Male Subjects ◽

Maximal Strain

Load-strain characteristics of tendinous tissues (Achilles tendon and aponeurosis) were determined in vivo for human medial gastrocnemius (MG) muscle. Seven male subjects exerted isometric plantar flexion torque while the elongation of tendinous tissues of MG was determined from the tendinous movements by using ultrasonography. The maximal strain of the Achilles tendon and aponeurosis, estimated separately from the elongation data, was 5.1 ± 1.1 and 5.9 ± 1.6%, respectively. There was no significant difference in strain between the Achilles tendon and aponeurosis. In addition, no significant difference in strain was observed between the proximal and distal regions of the aponeurosis. The results indicate that tendinous tissues of the MG are homogenously stretched along their lengths by muscle contraction, which has functional implications for the operation of the human MG muscle-tendon unit in vivo.

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Effects of eccentric training on mechanical properties of the plantar flexor muscle-tendon complex

Journal of Applied Physiology ◽

10.1152/japplphysiol.01313.2011 ◽

2013 ◽

Vol 114 (5) ◽

pp. 523-537 ◽

Cited By ~ 42

Author(s):

Alexandre Fouré ◽

Antoine Nordez ◽

Christophe Cornu

Keyword(s):

Mechanical Properties ◽

Achilles Tendon ◽

Plantar Flexion ◽

Triceps Surae ◽

Elastic Component ◽

Plantar Flexor ◽

Eccentric Training ◽

Tendon Stiffness ◽

Series Elastic Component ◽

Series Elastic

Eccentric training is a mechanical loading classically used in clinical environment to rehabilitate patients with tendinopathies. In this context, eccentric training is supposed to alter tendon mechanical properties but interaction with the other components of the muscle-tendon complex remains unclear. The aim of this study was to determine the specific effects of 14 wk of eccentric training on muscle and tendon mechanical properties assessed in active and passive conditions in vivo. Twenty-four subjects were randomly divided into a trained group ( n = 11) and a control group ( n = 13). Stiffness of the active and passive parts of the series elastic component of plantar flexors were determined using a fast stretch during submaximal isometric contraction, Achilles tendon stiffness and dissipative properties were assessed during isometric plantar flexion, and passive stiffness of gastrocnemii muscles and Achilles tendon were determined using ultrasonography while ankle joint was passively moved. A significant decrease in the active part of the series elastic component stiffness was found ( P < 0.05). In contrast, a significant increase in Achilles tendon stiffness determined under passive conditions was observed ( P < 0.05). No significant change in triceps surae muscles and Achilles tendon geometrical parameters was shown ( P > 0.05). Specific changes in muscle and tendon involved in plantar flexion are mainly due to changes in intrinsic mechanical properties of muscle and tendon tissues. Specific assessment of both Achilles tendon and plantar flexor muscles allowed a better understanding of the functional behavior of the muscle-tendon complex and its adaptation to eccentric training.

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