Musculotendinous Stiffness Research Articles

Effect of strength training on musculotendinous stiffness in elderly individuals

The present study deals with the question whether 24-week strength training alters neuromechanical properties of plantar flexors in elderly people (73-83 years). The first purpose of the present study was to evaluate the effect of strength training on musculotendinous (MT) stiffness of the triceps surae (TS). The training was performed twice per week and mainly consisted of three series of ten repetitions of calf-rise and leg-press exercises at 75% of the three-repetition maximum. Using quick-release movements at different levels of submaximal torques performed measurements of MT stiffness. Surface electromyograms (EMG) of each part of the TS and the tibialis anterior were also recorded. A stiffness index (SI), defined as the slope of the angular stiffness-torque relationship (SI(MT-Torque)), was used to quantify changes in MT stiffness. Results showed a significant decrease in SI(MT-Torque) by 25.2% following training (P < 0.05). The second purpose of the study was to evaluate whether neural mechanism has influences on this decrease. Therefore, an activation SI, defined as the slope of the angular stiffness-EMG relationship (SI(MT-EMG)) was used to overcome the influence of changes in agonist activity, and thus to quantify changes in MT intrinsic elastic properties. SI(MT-EMG) only decreased by 11.2% following training (P < 0.05). The present results underlined that MT stiffness decreases following training in elderly individuals, counterbalancing the effect of ageing. These changes seem not only to be due to peripheral but also to neural adaptations.

Design of a Controlled-Release Ergometer for the Measurement of Musculotendinous Stiffness of the Knee Flexors

The stiffness of muscle-tendon units (MTUs) influences many aspects of human movement from athletic performance to injury risk. Presently the controlled-release technique of measuring MTU stiffness has been applied almost exclusively to the distal joints of the body, i.e., the ankle. This is primarily because of the mechanical limitations of implementing this technique. However, in order to better understand how the elastic properties of the MTU affect both performance and injury potential, measurements of MTU stiffness of the more proximal joints must be made. The knee flexors are a logical choice because of the integral role of MTU stiffness of this muscle group in both hamstring strains and knee injury. The purpose of this study was to modify a commercial ergometer so that it could be used to measure the musculotendinous stiffness of the knee flexors. Data are presented for a representative participant to illustrate the feasibility and capability of this ergometer, and the measured MTU stiffness was 519 N.m.rad(-1) at a knee flexion moment of 100 N.m. Our results indicate that it is indeed possible to modify a commercial ergometer and measure musculotendinous stiffness of large muscle groups crossing proximal joints.

41 Effects of menstrual-cycle hormone fluctuations on musculotendinous stiffness and knee joint laxity: Implications for ACL injuries

41 Effects of menstrual-cycle hormone fluctuations on musculotendinous stiffness and knee joint laxity: Implications for ACL injuries

141 The influence of the menstrual cycle on knee laxity, isokinetic torque -position curve and musculotendinous stiffness in young women

141 The influence of the menstrual cycle on knee laxity, isokinetic torque -position curve and musculotendinous stiffness in young women

Age Effect on Jumping Techniques and Lower Limb Stiffness During Vertical Jump

The spring-mass system is a reasonable model of the whole phenomenon of musculotendinous stiffness of the lower limbs. This study was to investigate the developmental effect on jumping techniques and lower-limb stiffness during vertical jumping. Nine children and nine adults participated in the study. A Peak high-speed camera was synchronized with a Kistler force plate (600Hz) to collect the biomechanics parameters. Differences between mean values were analyzed by a t-test for independent samples. The present research showed that during downward countermovement, the 18-year-old group produced a larger displacement of ankle, knee, and CG in crouch phase (p < .05) and higher vertical ground reaction forces, whereas the CG was lowest (p < .05), and that the group produced greater leg and joint stiffness (p < .05) to create larger elastic energy generation and storage. For the 6-year-old group, the lower extremity could not be extended completely during push phase. Thus, the lack of prestretch, lower stiffness, and incomplete extension in the 6-year-old group is thought to influence jumping performance.

Effect of Static Stretching of the Biceps Brachii on Torque, Electromyography, and Mechanomyography During Concentric Isokinetic Muscle Actions

The purpose of this study was to determine the effect of an acute static stretching bout of the biceps brachii on torque, electromyography (EMG), and mechanomyography (MMG) during concentric isokinetic muscle actions. Eighteen (men, n = 10; women, n = 8) adult subjects (M ± SD age = 22.7 ± 2.8 years; weight = 78.0 ± 17.0 kg; height = 177.9 ± 11.0 cm) performed maximal isokinetic (30 and 270°·s−1) forearm flexion strength testing on 2 occasions while EMG and MMG were recorded. Subjects were randomly assigned to stretching (STR) or nonstretching (NSTR) protocols before strength testing. Two-way ANOVAs with repeated measures revealed significantly (p ≤ 0.05) greater torque for NSTR (M ± SEM = 36.9 ± 3.3 N·m) vs. STR (35.2 ± 3.3 N·m), significantly greater MMG amplitude for STR vs. NSTR for 30°·s−1 (STR = 93.5 ± 14.4 mV; NSTR = 63.1 ± 10.6 mV) and 270°·s−1 (STR = 207.6 ± 35.6 mV; NSTR = 136.4 ± 31.7 mV), and no difference in EMG amplitude. These results indicate that a greater ability to produce torque without prior stretching is related to the musculotendinous stiffness of the muscle rather than the number of motor units activated. This suggests that performing activities that reduce muscle stiffness (such as stretching), may be detrimental to performance.

THE EFFECT OF STATIC STRETCHING OF THE BICEPS BRACHII ON TORQUE, ELECTROMYOGRAPHY, AND MECHANOMYOGRAPHY.

Recent research has indicated that acute static stretching of a muscle prior to maximal muscular performance may negatively impact strength production, however, the mechanisms responsible for this phenomenon remain unclear. PURPOSE The purpose of this study was to determine the effect of an acute static stretching bout of the biceps brachii on torque, electromyography (EMG), and mechanomyography (MMG) during concentric isokinetic muscle actions. METHODS Eighteen (men, n = 10; women, n = 8) adult subjects (M±SD age = 22.7±2.8 yrs; weight = 78.0±17.0 kg; height = 177.9±11.0 cm) performed maximal isokinetic (30 and 270°s−1) forearm flexion strength testing on two occasions while EMG and MMG were recorded. Subjects were randomly assigned to stretching (STR) or non-stretching (NSTR) protocols before strength testing. RESULTS Two-way ANOVAs with repeated measures revealed no significant (p < 0.05) two-way interaction but a significant main effect for torque (NSTR = M±SEM = 36.9±3.3 Nm; STR = 35.2±3.3 Nm). In addition, a significant two-way interaction for MMG revealed greater amplitude values for STR versus NSTR for 30°s−1 (STR = 93.5±14.4 mV; NSTR = 63.1±10.6 mV) and 270°s−1 (STR = 207.6±35.6 mV; NSTR = 136.4±31.7 mV). For EMG amplitude, there was no significant two-way interaction or main effect for protocol. CONLUSION These results indicated that a greater ability to produce torque without prior stretching is related to the musculotendinous stiffness of the muscle rather than the number of motor units activated. This suggests that performing activities that reduce muscle stiffness (such as stretching or warming up) may be detrimental to performance.

Creatine Supplementation and Its Effect on Musculotendinous Stiffness and Performance

Creatine Supplementation and Its Effect on Musculotendinous Stiffness and Performance

Influence of long-term spaceflight on neuromechanical properties of muscles in humans

Reflex and elastic properties of the triceps surae (TS) were measured on 12 male cosmonauts 28-40 days before a 3- to 6-mo spaceflight, 2 or 3 days after return (R+2/+3) and a few days later (R+5/+6). H reflexes to electrical stimulations and T reflexes to tendon taps gave the reflex excitability at rest. Under voluntary contractions, reflex excitability was assessed by the stretch reflex, elicited by sinusoidal length perturbations. Stiffness measurements concerned the musculoarticular system in passive conditions and the musculotendinous complex in active conditions. Results indicated 1) no changes (P > 0.05) in H reflexes, whatever the day of test, and 2) increase in T reflexes (P < 0.05) by 57%, despite a decrease (P < 0.05) in musculoarticular stiffness (11%) on R+2/+3. T reflexes decreased (P < 0.05) between R+2/+3 and R+5/+6 (-21%); 3) increase in stretch reflexes (P < 0.05) on R+2/+3 by 31%, whereas it decreased (P < 0.05) between R+2/+3 and R+5/+6 (-29%). Musculotendinous stiffness was increased (P < 0.05) whatever the day of test (25%). Links between changes in reflex and stiffness were also studied by considering individual data. At R+2/+3, correlated changes between T reflexes and musculoarticular stiffness suggested that, besides central adaptive phenomena, musculoarticular structures took part in the reflex adaptation. This mechanical contribution was confirmed when data collected at R+2/+3 and R+5/+6 were used because correlations between changes in stretch reflexes and musculotendinous stiffness were improved. In conclusion, the present study shows that peripheral influences take part in reflex changes in gravitational unloaded muscles, but can only be revealed when central influences are reduced.

Musculo-tendinous and joint elastic characteristics during elbow flexion in children

Objective. The aim of the present research was to determine joint stiffness and musculo-tendinous stiffness in children. Background. No reliable data was available on differences in such parameters when comparing children and adults. Methods. Sinusoidal perturbations and quick-released movements were applied to the right elbow during flexion to determine joint stiffness and musculo-tendinous stiffness, respectively. For normalization purposes, stiffness indexes were calculated as the slope of the relationship between stiffness and torque. Results. Main results were that musculo-tendinous stiffness indexes obtained in children were similar to adult data deduced from the literature. On the other hand, joint stiffness indexes obtained in children were in the range 0.9–3.8 rad −1 and were lower than those reported in the literature for adults (between 4 and 8.5 rad −1 ). Conclusion. Since normalized musculo-tendinous stiffness is similar in children and in adults, it can be hypothesized that, during growth, increase in ability to produce force parallels elastic tissue development. Relevance Stiffness parameters could be used, in the context of other functional tests, to characterize changes in muscle properties in neuromuscular disorders when elastic tissues are supposed to be altered.

Effects of long-term spaceflight on mechanical properties of muscles in humans.

The effects of long-term spaceflight (90-180 days) on the contractile and elastic characteristics of the human plantarflexor muscles were studied in 14 cosmonauts before and 2-3 days after landing. Despite countermeasures practiced aboard, spaceflight was found to induce a decrease in maximal isometric torque (17%), whereas an index of maximal shortening velocity was found to increase (31%). In addition, maximal muscle activation evaluated during isokinetic tests decreased by 39%. Changes in musculotendinous stiffness and whole joint stiffness were characterized by means of quick-release movements and sinusoidal perturbations. Musculotendinous stiffness was found to be increased by 25%. Whole joint stiffness decreased under passive conditions (21%), whereas whole joint stiffness under active conditions remained unchanged after spaceflight (-1%). This invariance suggests an adaptive mechanism to counterbalance the decrease in stiffness of passive structures by an increased active stiffness. Changes in neural drive could participate in this equilibrium.

THE ACUTE EFFECTS OF PASSIVE STRETCHING ON ACTIVE MUSCULOTENDINOUS STIFFNESS1594

It has been established that acute muscle stretching is an effective means of reducing passive joint stiffness while increasing joint range of motion(JROM). Although a clear understanding of the mechanisms responsible for these effects remains elusive, it is commonly reported that passive stretching reduces the stiffness of the connective tissue structures crossing the joint, including muscle and tendon. If musculotendinous stiffness does decrease after passive stretching, then it is possible that stretching might also reduce the stiffness of the series elastic component, as described by A. V. Hill's (1938) classical muscle model. In turn, this might influence the storage of elastic energy during stretch-shortening movements. The purpose of this study, therefore, was to establish the effect of an acute bout of passive stretching on musculotendinous stiffness under active conditions (active stiffness). Ten male subjects (age: 24.9 ± 5.3 yrs) performed a modified version of a non-invasive technique designed by Cavagna (J. Appl. Physiol., 1970), to measure the active stiffness of the triceps surae muscle-tendon complex. Stiffness measures were taken before and after passively stretching the triceps surae muscle group. Ankle JROM was also measured before and after the stretching bout. Although ankle JROM increased significantly (from 29.3± 3.3° to 31.3 ± 3.2°; p < 0.01) as a result of the stretching procedure, active stiffness remained unchanged (28.7 ± 4.9 kN/m vs 28.4 ± 4.8 kN/m; p > 0.05). Therefore, while acute muscle stretching may reduce passive joint stiffness, stretching does not appear to alter the active stiffness of the musculotendinous unit. Consequently, it is unlikely that acute stretching exercises influence the storage of elastic energy in skills which take advantage of the stretch-shortening phenomenon.

The validity and reliability of a test of lower body musculotendinous stiffness.

The aim of this study was to investigate the validity and reliability of an in vivo test of lower body musculotendinous stiffness. Male subjects (n = 23) with at least 12 months of weight training experience performed a series of quasi-static muscular actions in a supine leg press position during which a brief perturbation was applied. The resulting damped oscillations enabled each subject's maximal musculotendinous stiffness for the lower body musculature to be estimated. To assess the individual's capacity to benefit from active stretch, subjects also performed both a static jump and a countermovement jump. Statistical analysis revealed no significant different between day 1 and day 2 stiffness values (P < 0.01), an interday reliability of r = 0.94 and a coefficient of variance of 8%. It was further demonstrated that maximal stiffness was significantly correlated to both isometric and concentric rate of force development (r = 0.50 and r = 0.54, respectively), and inversely related to the percentage difference between vertical jumps with and without prior stretch (r = -0.54). Such results tend to suggest that the test is valid and are discussed with reference to the restitution of elastic strain energy, muscle potentiation and the interaction effects of elastic recoil on dynamic muscular function. It was concluded that the assessment of stiffness of the lower body using the oscillation technique is a valid and reliable in vivo measure of musculotendinous stiffness.

Effect of intermittent eccentric contractions on symptoms of muscle microinjury

The purpose was to determine whether varying the duration of rest between contractions affects selected symptoms of eccentric contraction-induced skeletal muscle microinjury. Thirty-three women were assigned to three groups (N = 11). Each performed one bout of exercise with each arm involving 10 eccentric contractions of the elbow flexor muscles, lowering a load equaling 60% of maximal static force. One arm exercised continuously; the other exercised with rest periods of 15 s, 5 min, or 10 min between contractions, depending on the group. Preexercise and 0, 24, and 48 h postexercise, symptoms of microinjury in the elbow flexor muscles were assessed: soreness and changes in strength, resting elbow angle ("musculotendinous stiffness"), and arm girth ("swelling"). For all groups combined, 10 continuous contractions caused changes (P < 0.05) in all variables at every measurement time. For example, soreness ratings (0-10 scale) were 4.3 +/- 2.0 (24 h) and 4.3 +/- 2.1 (48 h) and strength was reduced 18% 0 h postexercise. Responses were similar with 15 s of rest between contractions. Although they were moderated, symptoms occurred even with 5 and 10 min of rest. With 10 min between contractions, soreness occurred (e.g., 2.4 +/- 1.5 [24 h]) and strength was 17% reduced 0 h postexercise. Results are most consistent with a mechanical cause of eccentric contraction-induced muscle microinjury, rather than a metabolic or other factor with a short recovery time, although involvement of the latter cannot be ruled out.

Musculotendinous stiffness: its relationship to eccentric, isometric, and concentric performance.

The purpose of this study was to quantify the relationship between musculotendinous stiffness and performance in eccentric, isometric, and concentric activities. Thirteen trained subjects performed a series of maximal effort eccentric, concentric, and isometric muscular contractions in a bench press-type movement. Additionally, subjects performed a series of quasi-static muscular contractions in a bench press movement. A brief perturbation was applied to the bar while these isometric efforts were maintained, and the resulting damped oscillations provided data pertaining to each subject's musculotendinous stiffness. Musculotendinous stiffness was significantly related to isometric and concentric performance (r = 0.57-0.78) but not to eccentric performance. These results are interpreted as demonstrating that the optimal musculotendinous stiffness for maximum concentric and isometric activities was toward the stiff end of the elasticity continuum. A stiffer musculotendinous unit may facilitate such performances by improving the force production capabilities of the contractile component, due to a combination of improved length and rate of shortening, and additionally by enhancing initial force transmission.

A dimensional analysis of physical performance and growth in boys.

ARTICLESA Dimensional Analysis of Physical Performance and Growth in BoysErling Asmussen, and Kr. Heebøll-NielsenErling Asmussen, and Kr. Heebøll-NielsenPublished Online:01 May 1955https://doi.org/10.1152/jappl.1955.7.6.593MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByA Conjugate Model for Dimensional Analysis18 July 2017 | Technometrics, Vol. 60, No. 1Influence de la morphologie, de VO2max et du coût énergetique sur la performance en natation chez de jeunes nageursScience & Sports, Vol. 18, No. 4Evaluation of musculotendinous stiffness in prepubertal children and adults, taking into account muscle activityDaniel Lambertz, Isabelle Mora, Jean-Francois Grosset, and Chantal Pérot1 July 2003 | Journal of Applied Physiology, Vol. 95, No. 1Intraindividual allometric development of aerobic power in 8- to 16-year-old boysMedicine & Science in Sports & Exercise, Vol. 34, No. 3Development of muscle strength in relation to training level and testosterone in young male soccer playersL. Hansen, J. Bangsbo, J. Twisk, and K. Klausen1 September 1999 | Journal of Applied Physiology, Vol. 87, No. 3Development of a Distance-Based Interval Throwing Program for Little League-Aged Athletes23 April 2016 | The American Journal of Sports Medicine, Vol. 24, No. 5Locomotor Estimation of Distance after Visual Scanning by Children and Adults25 June 2016 | Perception, Vol. 14, No. 3Bibliography31 May 2007 | Ergonomics, Vol. 28, No. 1Cardiac Response to Participation in Little League Baseball Competition as Determined by Telemetry17 March 2013 | Research Quarterly. American Association for Health, Physical Education and Recreation, Vol. 38, No. 3Significance of Age, Sex, and Maturity Differences in Upper Arm Composition17 March 2013 | Research Quarterly. American Association for Health, Physical Education and Recreation, Vol. 38, No. 2 More from this issue > Volume 7Issue 6May 1955Pages 593-603 https://doi.org/10.1152/jappl.1955.7.6.593PubMed14381334History Published online 1 May 1955 Published in print 1 May 1955 Metrics