Concentric muscle contractions before static stretching minimize, but do not remove, stretch-induced force deficits

2010 ◽  
Vol 108 (3) ◽  
pp. 637-645 ◽  
Author(s):  
Anthony D. Kay ◽  
Anthony J. Blazevich
Keyword(s):  
Achilles Tendon ◽  
Range Of Motion ◽  
Muscle Activity ◽  
Joint Moment ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Plantar Flexor ◽  
Tendon Stiffness ◽  
Concentric Contractions ◽  
Time Motion

The effects of concentric contractions and passive stretching on musculotendinous stiffness and muscle activity were studied in 18 healthy human volunteers. Passive and concentric plantar flexor joint moment data were recorded on an isokinetic dynamometer with simultaneous electromyogram (EMG) monitoring of the triceps surae, real-time motion analysis of the lower leg, and ultrasound imaging of the Achilles-medial gastrocnemius muscle-tendon junction. The subjects then performed six 8-s ramped maximal voluntary concentric contractions before repeating both the passive and concentric trials. Concentric moment was significantly reduced (6.6%; P < 0.01), which was accompanied by, and correlated with ( r = 0.60–0.94; P < 0.05), significant reductions in peak triceps surae EMG amplitude (10.2%; P < 0.01). Achilles tendon stiffness was significantly reduced (11.7%; P < 0.01), but no change in gastrocnemius medialis muscle operating length was detected. The subjects then performed three 60-s static plantar flexor stretches before being retested 2 and 30 min poststretch. A further reduction in concentric joint moment (5.8%; P < 0.01) was detected poststretch at 90% of range of motion, with no decrease in muscle activity or Achilles tendon stiffness, but a significant increase in muscle operating length and decrease in tendon length was apparent at this range of motion ( P < 0.05). Thirty minutes after stretching, muscle activity significantly recovered to pre-maximal voluntary concentric contractions levels, whereas concentric moment and Achilles tendon stiffness remained depressed. These data show that the performance of maximal concentric contractions can substantially reduce neuromuscular activity and muscle force, but this does not prevent a further stretch-induced loss in active plantar flexor joint moment. Importantly, the different temporal changes in EMG and concentric joint moment indicate that a muscle-based mechanism was likely responsible for the force losses poststretch.

Isometric contractions reduce plantar flexor moment, Achilles tendon stiffness, and neuromuscular activity but remove the subsequent effects of stretch

2009 ◽  
Vol 107 (4) ◽  
pp. 1181-1189 ◽  
Author(s):  
Anthony D. Kay ◽  
Anthony J. Blazevich
Keyword(s):  
Achilles Tendon ◽  
Muscle Activity ◽  
Joint Moment ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Isometric Contractions ◽  
Plantar Flexor ◽  
Tendon Stiffness ◽  
Neuromuscular Activity ◽  
Passive Joint

The effects of isometric contractions and passive stretching on muscle-tendon mechanics and muscle activity were studied in 16 healthy human volunteers. First, peak concentric and passive ankle joint moment data were recorded on an isokinetic dynamometer with electromyographic monitoring of the triceps surae; real-time motion analysis of the lower leg and ultrasound imaging of the Achilles-medial gastrocnemius muscle-tendon junction were simultaneously conducted. Second, the subjects performed six 8-s maximal voluntary isometric contractions (MVICs) before repeating the passive and active trials. Although there was no decrease in isometric joint moment after MVICs, peak concentric moment was significantly reduced (11.5%, P < 0.01). This was accompanied by, and correlated with ( r = 0.90, P < 0.01), significant reductions in peak triceps surae electromyographic amplitude (21.0%, P < 0.01). Achilles tendon stiffness (10.9%, P < 0.01) and passive joint moment (4.9%, P < 0.01) were also significantly reduced. Third, the subjects performed three 60-s static plantar flexor stretches before being retested 2 and 30 min after stretch. The stretch protocol caused no significant change in any measure. At 30 min after stretching, significant recovery in concentric moment and muscle activity was detected at dorsiflexed joint angles, while Achilles tendon stiffness and passive joint moment remained significantly reduced. These data show that the performance of MVICs interrupts the normal stretch-induced losses in active and passive plantar flexor joint moment and neuromuscular activity, largely because concentric strength and tendon properties were already affected. Importantly, the decrease in Achilles tendon stiffness remained 30 min later, which may be an important etiological factor for muscle-tendon strain injury risk.

Moderate-duration static stretch reduces active and passive plantar flexor moment but not Achilles tendon stiffness or active muscle length

2009 ◽  
Vol 106 (4) ◽  
pp. 1249-1256 ◽  
Author(s):  
Anthony D. Kay ◽  
Anthony J. Blazevich
Keyword(s):  
Mechanical Properties ◽  
Achilles Tendon ◽  
Muscle Stiffness ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Static Stretch ◽  
Tendon Stiffness ◽  
Neuromuscular Activity ◽  
Time Motion ◽  
The Impact

The effects of static stretch on muscle and tendon mechanical properties and muscle activation were studied in fifteen healthy human volunteers. Peak active and passive moment data were recorded during plantar flexion trials on an isokinetic dynamometer. Electromyography (EMG) monitoring of the triceps surae muscles, real-time motion analysis of the lower leg, and ultrasound imaging of the Achilles-medial gastrocnemius muscle-tendon junction were simultaneously conducted. Subjects performed three 60-s static stretches before being retested 2 min and 30 min poststretch. There were three main findings in the present study. First, peak concentric moment was significantly reduced after stretch; 60% of the deficit recovered 30 min poststretch. This was accompanied by, and correlated with ( r = 0.81 ; P < 0.01) reductions in peak triceps surae EMG amplitude, which was fully recovered at 30 min poststretch. Second, Achilles tendon length was significantly shorter during the concentric contraction after stretch and at 30 min poststretch; however, no change in tendon stiffness was detected. Third, passive joint moment was significantly reduced after stretch, and this was accompanied by significant reductions in medial gastrocnemius passive muscle stiffness; both measures fully recovered by 30 min poststretch. These data indicate that the stretching protocol used in this study induced losses in concentric moment that were accompanied by, and related to, reductions in neuromuscular activity, but they were not associated with alterations in tendon stiffness or shorter muscle operating length. Reductions in passive moment were associated with reductions in muscle stiffness, whereas tendon mechanics were unaffected by the stretch. Importantly, the impact on mechanical properties and neuromuscular activity was minimal at 30 min poststretch.

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

2013 ◽  
Vol 114 (5) ◽  
pp. 523-537 ◽  
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.

Comparison of Plantar Flexor Musculotendinous Stiffness, Geometry, and Architecture in Male Runners With and Without a History of Tibial Stress Fracture

2015 ◽  
Vol 31 (1) ◽  
pp. 41-47 ◽  
Author(s):  
Derek N. Pamukoff ◽  
J. Troy Blackburn
Keyword(s):  
Achilles Tendon ◽  
Stress Fracture ◽  
Joint Stiffness ◽  
Medial Gastrocnemius ◽  
Plantar Flexor ◽  
Fascicle Length ◽  
Tendon Stiffness ◽  
Tibial Stress Fracture ◽  
History Of ◽  
Musculotendinous Stiffness

Greater lower extremity joint stiffness may be related to the development of tibial stress fractures in runners. Musculotendinous stiffness is the largest contributor to joint stiffness, but it is unclear what factors contribute to musculotendinous stiffness. The purpose of this study was to compare plantar flexor musculotendinous stiffness, architecture, geometry, and Achilles tendon stiffness between male runners with and without a history of tibial stress fracture. Nineteen healthy runners (age = 21 ± 2.7 years; mass = 68.2 ± 9.3 kg; height = 177.3 ± 6.0 cm) and 19 runners with a history of tibial stress fracture (age = 21 ± 2.9 years; mass = 65.3 ± 6.0 kg; height = 177.2 ± 5.2 cm) were recruited from community running groups and the university’s varsity and club cross-country teams. Plantar flexor musculotendinous stiffness was estimated from the damped frequency of oscillatory motion about the ankle follow perturbation. Ultrasound imaging was used to measure architecture and geometry of the medial gastrocnemius. Dependent variables were compared between groups via one-way ANOVAs. Previously injured runners had greater plantar flexor musculotendinous stiffness (P< .001), greater Achilles tendon stiffness (P= .004), and lesser Achilles tendon elongation (P= .003) during maximal isometric contraction compared with healthy runners. No differences were found in muscle thickness, pennation angle, or fascicle length.

Differential displacement of the human soleus and medial gastrocnemius aponeuroses during isometric plantar flexor contractions in vivo

2004 ◽  
Vol 97 (5) ◽  
pp. 1908-1914 ◽  
Author(s):  
Jens Bojsen-Møller ◽  
Philip Hansen ◽  
Per Aagaard ◽  
Ulla Svantesson ◽  
Michael Kjaer ◽  
...  
Keyword(s):  
Knee Joint ◽  
Achilles Tendon ◽  
Plantar Flexion ◽  
Human Locomotion ◽  
Muscular Contraction ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Plantar Flexor ◽  
Flexion Moment

The human triceps surae muscle-tendon complex is a unique structure with three separate muscle compartments that merge via their aponeuroses into the Achilles tendon. The mechanical function and properties of these structures during muscular contraction are not well understood. The purpose of the study was to investigate the extent to which differential displacement occurs between the aponeuroses of the medial gastrocnemius (MG) and soleus (Sol) muscles during plantar flexion. Eight subjects (mean ± SD; age 30 ± 7 yr, body mass 76.8 ± 5.5 kg, height 1.83 ± 0.06 m) performed maximal isometric ramp contractions with the plantar flexor muscles. The experiment was performed in two positions: position 1, in which the knee joint was maximally extended, and position 2, in which the knee joint was maximally flexed (125°). Plantarflexion moment was assessed with a strain gauge load cell, and the corresponding displacement of the MG and Sol aponeuroses was measured by ultrasonography. Differential shear displacement of the aponeurosis was quantified by subtracting displacement of Sol from that of MG. Maximal plantar flexion moment was 36% greater in position 1 than in position 2 (132 ± 20 vs. 97 ± 11 N·m). In position 1, the displacement of the MG aponeurosis at maximal force exceeded that of the Sol (12.6 ± 1.7 vs. 8.9 ± 1.5 mm), whereas in position 2 displacement of the Sol was greater than displacement of the MG (9.6 ± 1.0 vs. 7.9 ± 1.2 mm). The amount and “direction” of shear between the aponeuroses differed significantly between the two positions across the entire range of contraction, indicating that the Achilles tendon may be exposed to intratendinous shear and stress gradients during human locomotion.

Functional Ankle Range of Motion but Not Peak Achilles Tendon Force Diminished With Heel-Rise and Jumping Tasks After Achilles Tendon Repair

2021 ◽  
pp. 036354652110194
Author(s):  
Jennifer A. Zellers ◽  
Josh R. Baxter ◽  
Karin Grävare Silbernagel
Keyword(s):  
Achilles Tendon ◽  
Range Of Motion ◽  
Tendon Rupture ◽  
Achilles Tendon Rupture ◽  
Tendon Repair ◽  
Mean Difference ◽  
Triceps Surae ◽  
Plantar Flexor ◽  
Achilles Tendon Repair ◽  
Ankle Function

Background: Deficits in sporting performance after Achilles tendon repair may be due to changes in musculotendinous unit structure, including tendon elongation and muscle fascicle shortening. Purpose/Hypothesis: The purpose was to discern whether Achilles tendon rupture reduces triceps surae muscle force generation, alters functional ankle range of motion, or both during sports-related tasks. We hypothesized that individuals who have undergone Achilles tendon repair lack the functional ankle range of motion needed to complete sports-related tasks. Study Design: Descriptive laboratory study. Methods: The study included individuals 1 to 3 years after treatment of Achilles tendon rupture with open repair. Participants (n = 11) completed a heel-rise task and 3 jumping tasks. Lower extremity biomechanics were analyzed using motion capture. Between-limb differences were tested using paired t test. Results: Pelvic vertical displacement was reduced during the heel-rise (mean difference, −12.8%; P = .026) but not during the jumping task ( P > .1). In the concentric phase of all tasks, peak ankle plantarflexion angle (range of mean difference, −19.2% to −48.8%; P < .05) and total plantar flexor work (defined as the area under the plantar flexor torque – ankle angle curve) (range of mean difference, −9.5% to −25.7%; P < .05) were lower on the repaired side relative to the uninjured side. No significant differences were seen in peak Achilles tendon load or impulse with any of the tasks. There were no differences in plantar flexor work or Achilles tendon load parameters during eccentric phases. Conclusion: Impaired task performance or increased demands on proximal joints were observed on the repaired side in tasks isolating ankle function. Tasks that did not isolate ankle function appeared to be well recovered, although functional ankle range of motion was reduced with rupture. Reduced plantar flexor muscle-tendon unit work supports previous reports that an elongated tendon and shorter muscle fascicles caused by Achilles tendon rupture constrain functional capacity. Achilles tendon peak load and impulse were not decreased, suggesting that reduced and shifted functional ankle range of motion (favoring dorsiflexion) underlies performance deficits. Clinical Relevance: These findings point to the need to reduce tendon elongation and restore muscle length of the triceps surae after Achilles tendon rupture in order to address musculature that is short but not necessarily weak for improved performance with sports-related activities.

scholarly journals Effects of long-term athletic training on muscle morphology and tendon stiffness in preadolescence: association with jump performance

2020 ◽  
Vol 120 (12) ◽  
pp. 2715-2727
Author(s):  
Nikolaos Pentidis ◽  
Falk Mersmann ◽  
Sebastian Bohm ◽  
Erasmia Giannakou ◽  
Nickos Aggelousis ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Achilles Tendon ◽  
Muscle Hypertrophy ◽  
Muscle Thickness ◽  
Pennation Angle ◽  
Triceps Surae ◽  
Plantar Flexors ◽  
Tendon Stiffness ◽  
Jumping Performance

Abstract Purpose Evidence on training-induced muscle hypertrophy during preadolescence is limited and inconsistent. Possible associations of muscle strength and tendon stiffness with jumping performance are also not investigated. We investigated the thickness and pennation angle of the gastrocnemius medialis muscle (GM), as indicators for potential muscle hypertrophy in preadolescent athletes. Further, we examined the association of triceps surae muscle–tendon properties with jumping performance. Methods Eleven untrained children (9 years) and 21 similar-aged artistic gymnastic athletes participated in the study. Muscle thickness and pennation angle of the GM were measured at rest and muscle strength of the plantar flexors and Achilles tendon stiffness during maximum isometric contractions. Jumping height in squat (SJ) and countermovement jumps (CMJ) was examined using a force plate. We evaluated the influence of normalised muscle strength and tendon stiffness on jumping performance with a linear regression model. Results Muscle thickness and pennation angle did not differ significantly between athletes and non-athletes. In athletes, muscle strength was greater by 25% and jumping heights by 36% (SJ) and 43% (CMJ), but Achilles tendon stiffness did not differ between the two groups. The significant predictor for both jump heights was tendon stiffness in athletes and normalised muscle strength for the CMJ height in non-athletes. Conclusion Long-term artistic gymnastics training during preadolescence seems to be associated with increased muscle strength and jumping performance but not with training-induced muscle hypertrophy or altered tendon stiffness in the plantar flexors. Athletes benefit more from tendon stiffness and non-athletes more from muscle strength for increased jumping performance.

scholarly journals Muscle fibre recruitment can respond to the mechanics of the muscle contraction

2006 ◽  
Vol 3 (9) ◽  
pp. 533-544 ◽  
Author(s):  
James M Wakeling ◽  
Katrin Uehli ◽  
Antra I Rozitis
Keyword(s):  
Motor Unit ◽  
Muscle Activity ◽  
The Body ◽  
Motor Unit Recruitment ◽  
Triceps Surae ◽  
Medial Gastrocnemius ◽  
Muscle Fibres ◽  
Strain Rates ◽  
Lower Velocity ◽  
Muscle Fascicle

This study investigates the motor unit recruitment patterns between and within muscles of the triceps surae during cycling on a stationary ergometer at a range of pedal speeds and resistances. Muscle activity was measured from the soleus (SOL), medial gastrocnemius (MG) and lateral gastrocnemius (LG) using surface electromyography (EMG) and quantified using wavelet and principal component analysis. Muscle fascicle strain rates were quantified using ultrasonography, and the muscle–tendon unit lengths were calculated from the segmental kinematics. The EMG intensities showed that the body uses the SOL relatively more for the higher-force, lower-velocity contractions than the MG and LG. The EMG spectra showed a shift to higher frequencies at faster muscle fascicle strain rates for MG: these shifts were independent of the level of muscle activity, the locomotor load and the muscle fascicle strain. These results indicated that a selective recruitment of the faster motor units occurred within the MG muscle in response to the increasing muscle fascicle strain rates. This preferential recruitment of the faster fibres for the faster tasks indicates that in some circumstances motor unit recruitment during locomotion can match the contractile properties of the muscle fibres to the mechanical demands of the contraction.

scholarly journals Training-induced increase in Achilles tendon stiffness affects tendon strain pattern during running

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6764 ◽  
Author(s):  
Amelie Werkhausen ◽  
Neil J. Cronin ◽  
Kirsten Albracht ◽  
Gøran Paulsen ◽  
Askild V. Larsen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Achilles Tendon ◽  
Stance Phase ◽  
Training Group ◽  
Triceps Surae ◽  
Control Group ◽  
Tendon Stiffness ◽  
Strain Pattern ◽  
Tendon Strain ◽  
Triceps Surae Muscles

Background During the stance phase of running, the elasticity of the Achilles tendon enables the utilisation of elastic energy and allows beneficial contractile conditions for the triceps surae muscles. However, the effect of changes in tendon mechanical properties induced by chronic loading is still poorly understood. We tested the hypothesis that a training-induced increase in Achilles tendon stiffness would result in reduced tendon strain during the stance phase of running, which would reduce fascicle strains in the triceps surae muscles, particularly in the mono-articular soleus. Methods Eleven subjects were assigned to a training group performing isometric single-leg plantarflexion contractions three times per week for ten weeks, and another ten subjects formed a control group. Before and after the training period, Achilles tendon stiffness was estimated, and muscle-tendon mechanics were assessed during running at preferred speed using ultrasonography, kinematics and kinetics. Results Achilles tendon stiffness increased by 18% (P < 0.01) in the training group, but the associated reduction in strain seen during isometric contractions was not statistically significant. Tendon elongation during the stance phase of running was similar after training, but tendon recoil was reduced by 30% (P < 0.01), while estimated tendon force remained unchanged. Neither gastrocnemius medialis nor soleus fascicle shortening during stance was affected by training. Discussion These results show that a training-induced increase in Achilles tendon stiffness altered tendon behaviour during running. Despite training-induced changes in tendon mechanical properties and recoil behaviour, the data suggest that fascicle shortening patterns were preserved for the running speed that we examined. The asymmetrical changes in tendon strain patterns supports the notion that simple in-series models do not fully explain the mechanical output of the muscle-tendon unit during a complex task like running.

scholarly journals Enthalpy efficiency of the soleus muscle explains improvements in running economy

2020 ◽  
Author(s):  
Sebastian Bohm ◽  
Falk Mersmann ◽  
Alessandro Santuz ◽  
Adamantios Arampatzis
Keyword(s):  
Achilles Tendon ◽  
Soleus Muscle ◽  
Intervention Group ◽  
Running Economy ◽  
Metabolic Energy ◽  
Energetic Cost ◽  
Plantar Flexor ◽  
Tendon Stiffness ◽  
Flexor Strength ◽  
Human Running

AbstractDuring human running, the soleus, as the main plantar flexor muscle, generates the majority of the mechanical work through active shortening. The fraction of chemical energy that is converted into muscular work (i.e. the enthalpy efficiency) depends on the muscle shortening velocity. Here, we investigated the soleus muscle fascicle behavior during running with respect to the enthalpy efficiency as a mechanism that could explain previously reported improvements in running economy after exercise-induced increases of plantar flexor strength and Achilles tendon stiffness. Healthy amateur runners were randomly assigned to a control (n=10) or intervention group (n=13), which performed a specific 14-week muscle-tendon training. Significant increases in plantar flexor maximum strength (10%) and Achilles tendon stiffness (31%) yet reduced metabolic cost of running (4%) was found only in the intervention group (p<0.05). Following training, the soleus fascicle velocity profile throughout stance was altered, with the fascicles operating at a higher enthalpy efficiency during the phase of muscle-tendon unit lengthening (15%) and in average over stance (7%, p<0.05). These findings show that the improvements in energetic cost following increases in plantar flexor strength and Achilles tendon stiffness can be attributed to increased enthalpy efficiency of the operating soleus. This provides the first experimental evidence that the soleus enthalpy efficiency is a determinant of human running economy. Furthermore, the current results imply that the soleus energy production in the first part of the stance phase were the muscle-tendon unit is lengthening is crucial for the overall metabolic energy cost of running.

Sign in / Sign up

Export Citation Format

Share Document