Muscular viscoelastic characteristics of athletes participating in the European Master Indoor Athletics Championship

The Myometric Assessment of Achilles Tendon and Soleus Muscle Stiffness before and after a Standardized Exercise Test in Elite Female Volleyball and Handball Athletes-A Quasi-Experimental Study

Background: The high prevalence of injuries in female athletes necessitates a course of action that not only enhances research in this field but also incorporates improved prevention programs and regular health monitoring of highly stressed structures such as tendons and muscles. Since myometry is already used by coaches and physiotherapists, it is important to investigate whether tissue stiffness varies in different types of sports, and whether such measures are affected by an acute training session. Methods: Myometric measurements of the Achilles tendon (AT) and soleus muscle (SM) were performed in the longitudinal plane and relaxed tendon position. In total, 38 healthy professional female athletes were examined, applying a quasi-experimental study design, with subgroup analysis performed for different sports. To investigate the stiffness of the AT and SM, 24 female handball and volleyball athletes performed a standardized maximal incremental performance test on a treadmill. In this subgroup, myometric measurements were taken before and after the exercise test. Results: The measurements showed no significant difference between the mean pre- (AT: 661.46 N/m; SM 441.48 N/m) and post-exercise stiffness (AT: 644.71 N/m; SM: 439.07 N/m). Subgroup analysis for different types of sports showed significantly lower AT and SM stiffness in swimming athletes compared to handball (p = 0.002), volleyball (p = 0.000) and hammer throw athletes (p = 0.008). Conclusions: Myometry can be performed on the same day as an acute training session in healthy female professional volleyball and handball athletes. Female swimmers have significantly lower AT and SM stiffness compared to female handball, volleyball and hammer throw athletes. These results show that the stiffness differences in the AT and SM can be assessed by myometry.

Reliability of Ultrasound Shear Wave Elastography for Evaluating Psoas Major and Quadratus Lumborum Stiffness: Gender and Physical Activity Effects

OBJECTIVE

We aimed to assess the reliability of quantifying psoas major (PM) and quadratus lumborum (QL) stiffness with ultrasound shear wave elastography (SWE), and to explore the effects of gender and physical activity on muscle stiffness.

METHODS

Fifty-two healthy participants (18-32 y) were recruited. To determine reliability, 29 of them underwent repeated SWE measurements of PM and QL stiffness by an operator on the same day. The intra-class correlation coefficients (ICC3,1), standard error of measurement (SEM) and minimal detectable change with 95% confidence interval (MDC95) were calculated. The rest participants underwent a single measurement. Two-way MANCOVA was conducted for the effects of gender and physical activity on muscle stiffness.

RESULTS

The observed reliability for PM (ICC3,1 = 0.89-0.92) and QL (ICC3,1 = 0.79-0.82) were good-to-excellent and good, respectively. The SEM (kPa) was 0.79-1.03 and 1.23-1.28, and the MDC95 (kPa) was 2.20-2.85 and 3.41-3.56 for PM and QL, respectively. After BMI adjustment, both gender (PM: F = 10.15, p = 0.003; QL: F = 18.07, p < 0.001) and activity level (PM: F = 5.90, p = 0.005; QL: F = 6.33, p = 0.004) influenced muscle stiffness. The female and inactive groups exhibited higher stiffness in both muscles.

CONCLUSION

SWE is reliable for quantifying the stiffness of PM and QL. Female and physical inactivity may elevate PM and QL stiffness, underscoring the importance of accounting for these factors in muscle stiffness investigations. Larger prospective studies are needed to further elucidate their effects.

Correlation between Physical Performance and Tensiomyographic and Myotonometric Parameters in Older Adults

BACKGROUND

To examine the correlation between physical performance and muscle strength and the variables obtained from tensiomyography and myotonometry.

METHODS

Fifty-two older adults able to complete functional tests participated in this observational study. Variables of maximal radial muscle displacement (Dm) and contraction time (Tc) (using tensiomyography) and muscle stiffness (using myotonometry) of the rectus femoris and vastus lateralis muscles were assessed. Physical performance (Short Physical Performance Battery, Timed Up and Go, Five Times Sit to Stand, and walking speed), isometric knee extension strength, and grip strength were assessed. A correlation analysis was performed between all the variables.

RESULTS

A significant correlation between the Short Physical Performance Battery and the rectus femoris (rho = 0.491) and vastus lateralis Dm (rho = 0.329) was found. Significant correlations between the Five Times Sit to Stand Test and the Dm values of the rectus femoris (rho = -0.340) and Dm (rho = -0.304), and stiffness (rho = -0.345) in the vastus lateralis, were also found. No significant correlations were found between tensiomyography and myotonometry, the Timed Up and Go, and walking speed, nor between tensiomyography and myotonometry and grip strength or isometric knee extension strength.

CONCLUSIONS

Functional tests should be prioritized in the assessment of older adults, but further research into muscle quality using technology is advisable.

An Integrated Approach to Skeletal Muscle Health in Aging

A decline in muscle mass and function represents one of the most problematic changes associated with aging, and has dramatic effects on autonomy and quality of life. Several factors contribute to the inexorable process of sarcopenia, such as mitochondrial and autophagy dysfunction, and the lack of regeneration capacity of satellite cells. The physiologic decline in muscle mass and in motoneuron functionality associated with aging is exacerbated by the sedentary lifestyle that accompanies elderly people. Regular physical activity is beneficial to most people, but the elderly need well-designed and carefully administered training programs that improve muscle mass and, consequently, both functional ability and quality of life. Aging also causes alteration in the gut microbiota composition associated with sarcopenia, and some advances in research have elucidated that interventions via the gut microbiota-muscle axis have the potential to ameliorate the sarcopenic phenotype. Several mechanisms are involved in vitamin D muscle atrophy protection, as demonstrated by the decreased muscular function related to vitamin D deficiency. Malnutrition, chronic inflammation, vitamin deficiencies, and an imbalance in the muscle-gut axis are just a few of the factors that can lead to sarcopenia. Supplementing the diet with antioxidants, polyunsaturated fatty acids, vitamins, probiotics, prebiotics, proteins, kefir, and short-chain fatty acids could be potential nutritional therapies against sarcopenia. Finally, a personalized integrated strategy to counteract sarcopenia and maintain the health of skeletal muscles is suggested in this review.

Relationship between Muscle-Tendon Stiffness and Drop Jump Performance in Young Male Basketball Players during Developmental Stages

BACKGROUND

The relationship between stiffness and drop jump performance in athletes in various stages of development has yet to be fully investigated. The first aim of this study was to investigate the association between the stiffness of the patellar and quadriceps tendon (PT, QT), gastrocnemius-Achilles tendon unit (GAT), and rectus femoris (RF) using drop jump (DJ) performance in young basketball players. The second aim was to investigate possible variations in the stiffness levels of those tissues in different developmental stages.

METHODS

The stiffness levels of the GAT, PT, QT, and RF were measured in both limbs in 73 male basketball players aged 12 to 18 years. The reactive strength index (RSI), contact time (CT) and jump height (JH) during 30 and 40 cm DJs were also measured.

RESULTS

Pearson correlation coefficients showed a significant association between DJ performance and PT, QT, GAT, and RF dynamic stiffness. Moreover, the youngest subjects were found to have lower stiffness values than the older ones.

CONCLUSIONS

Tissue stiffness can affect athletic performance by modifying the stretch-shortening cycle in young basketball players. Stiffness of muscles and tendons increases during the maturation process. Further investigations could shed light on the effect of training on the stiffness of muscles and tendons.

Impact of Body Composition Parameters on Lung Function in Athletes

Background: Given the potential risk of unhealthy weight management, the monitoring of body composition in athletes is advised. However, limited data reveal how body composition measurements can benefit athlete health and, in particular, respiratory function. The aim of this study is to evaluate the impact of body composition on pulmonary function in a population of adult athletes. Methods: Data from 435 competitive adult athletes regarding body compositions parameters and spirometry are retrospectively analyzed. Results: Our study population consists of 335 males and 100 female athletes. Muscle mass and fat-free mass are significantly and positively associated with forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC) in the male and female population, while waist-to-height ratio is negatively associated with FEV1, FVC, and FEV1/FVC in the male population. In multivariable analysis, muscle mass and fat-free mass show significant association with FEV1 and FVC in both males and females (p < 0.05), and waist-to-height ratio is significantly and inversely associated with FEV1 and FVC in males (p < 0.05). Conclusions: Fat-free mass and muscle mass are positively and independently associated with FEV1 and FVC in athletes of both genders, and waist-to-height ratio is inversely associated with FEV1 and FVC only among male athletes. These findings suggest that body composition in athletes may be helpful in monitoring respiratory function.

Reliability of a New Indentometer Device for Measuring Myofascial Tissue Stiffness

Changes in tissue stiffness are associated with pathological conditions such as myofascial pain and increased risk of muscle injury. Furthermore, they have been shown to modify performance indicators such as running economy or jump height. Indentometry is an affordable way to assess tissue stiffness. However, to date, there is a paucity of studies examining the measurement properties of available devices. With this trial, we aimed to evaluate the reliability of the “IndentoPro”. Two investigators repeatedly measured the stiffness of the lateral head of the gastrocnemius muscle in healthy participants (N = 35), using 5 and 10 mm indentation depths. Intraclass Correlation Coefficients (ICC) revealed moderate inter-rater reliability (5 mm: ICC3,1 0.74, 95%CI = 0.54 to 0.86, p < 0.001; 10 mm: ICC3,1 0.59, 95%CI = 0.27 to 0.78, p < 0.001) and good intra-rater reliability (5 mm: ICC3,1 0.84, 95%CI = 0.71 to 0.92, p < 0.001; 10 mm: ICC3,1 0.83, 95%CI = 0.69 to 0.91, p < 0.001). No correlations between age, height, weight, BMI, skinfold thickness and myofascial tissue stiffness were observed (p > 0.5). In conclusion, the IndentoPro is reliable in assessing calf tissue stiffness, but the predictors of stiffness remain unclear.

The comparison of tone and viscoelastic properties of superior orbicularis oris muscle in multiple sclerosis patients to healthy individuals

BACKGROUND

The orbicularis oris muscle is an important muscle for oral perception in mouth and swallowing rehabilitation. The muscle can be affected in patients with multiple sclerosis for many reasons. It is important to understand the quantitative changes in this muscle to determine the many problems associated with the cranio-facial region in multiple sclerosis. Therefore, this study aimed to compare the mechanical properties of the orbicularis oris muscle between MS patients and healthy individuals.

METHODS

A total of 55 individuals (28 with multiple sclerosis and 27 healthy) who met the inclusion criteria were evaluated. The tone and viscoelastic properties (elasticity and stiffness) of the superior orbicularis oris muscle of both groups were evaluated bilaterally in the supine position with the MyotonPro® (Myoton AS, Estonia) device. The reference point of the muscle is accepted as the right and left paramedial philtrum dimple.

RESULTS

It was observed that there was no difference in terms of stiffness values of the right and left orbicularis oris muscles of both groups (p>0.05). The tone and the elasticity of the muscle on both sides were higher in the HI group than MS group (p<0.05).

CONCLUSION

We think that the orbicularis oris muscle has a central location in the facial region, and that this muscle may be the key muscle for the symptoms arising from many neurological mechanisms. The decrease in muscle tone and elasticity may be the beginning of the changes in MS patients. We believe that the data from this muscle will be useful for comparative studies.

CARDIOVASCULAR RESPONSE OF ATHLETES UNDER DIFFERENT TRAINING CONDITIONS

ABSTRACT Introduction: Improving cardiovascular function is one of the main training goals of many sports. Objective: To understand the characteristics of the cardiovascular response of athletes under different training conditions. Methods: Thirty male basketball students were enrolled. The subjects were divided into A and B groups according to their years of training, with 15 students in each group. Exercise fatigue tests were performed, starting at a low intensity and gradually increasing the load to a relatively high degree of fatigue. Results: The RMSSD value was 42.82±31.41ms in group A and 46.48±35.26ms in group B undera low fatigue state. The LF/HF value of the athletes in group A was 2.86±1.47 and the LF/HF value of the athletes in group B was 2.94±1.68. The RMSSD value was 40.78±31.17ms and 32.37±36.42ms for groups A and B, respectively, undera high fatigue state. Conclusions: Athletes with more years of training can mobilize more cardiac reserves to meet the increase in exercise load in a fatigue state and have better autonomic nervous regulation in the process of reaching a higher degree of fatigue state. Level of evidence II; Therapeutic studies - investigation of treatment results.

The Relation of Body Mass Index to Muscular Viscoelastic Properties in Normal and Overweight Individuals

Background: The body mass index (BMI) is closely related to fat tissue, which may have direct or indirect effects on muscle function. Previous studies have evaluated BMI and muscle viscoelastic properties in vivo in older people or individual sexes; however, the relationship between BMI and muscular viscoelastic properties is still unknown. Aims: The purpose of this study was to determine the correlation of BMI with muscular viscoelastic properties, and to compare these properties in a young sedentary population with normal and overweight individuals. Methods: A total of 172 healthy sedentary individuals (mean age, 26.00 ± 5.45 years) were categorized by sex (male and female) and BMI classification (normal (BMI, 18.50-24.99 kg/m²), overweight (BMI = 25.00-29.99 kg/m²)). Body weight was evaluated using an electronic scale, while height was measured using a standard stadiometer. BMI was calculated by dividing the weight in kilograms by the square of height in meters. The viscoelastic properties (tone, stiffness, and elasticity) of the biceps brachii (BB) and biceps femoris (BF) muscles were measured bilaterally using the MyotonPRO device at rest. Results: The bilateral BF tone and stiffness, right BB stiffness, and elasticity showed weak correlations with BMI in all participants. Furthermore, the bilateral BF tone and stiffness, right BB stiffness and elasticity, and left BB stiffness were weakly positively correlated with male sex. Only the right BB elasticity was weakly positively correlated with BMI in females (p < 0.05). No correlation with BMI was determined for other viscoelastic properties (p > 0.05). The overweight group showed increased bilateral BF stiffness and tone, right BB stiffness, and reduced bilateral BB elasticity compared to the normal-weight group (p < 0.05), while other viscoelastic properties were similar (p > 0.05). Greater bilateral BB tone, BF tone and stiffness, and lower BF elasticity were observed in males than in females (p < 0.05), but other viscoelastic properties were not significantly different (p < 0.05). No effect of BMI-sex interactions was found on viscoelastic properties (p > 0.05). Conclusions: The BB and BF viscoelastic properties were weakly correlated with BMI. Males showed greater muscle tone and stiffness, and lower elasticity. The overweight individuals showed increased stiffness and tone, particularly in lower extremities, and reduced elasticity in upper extremities. The effect of BMI-sex interactions on the viscoelastic properties was not clear. Higher BMI (increased mechanical load) might cause the human body to develop different muscular viscoelastic adaptations in the extremities.

Age Related Changes of Superior Orbicularis Oris Muscle in Terms of Tone and Viscoelastic Properties

OBJECTIVE

To examine the age-related changes in the viscoelastic properties and tone of the superior orbicularis oris muscle by a portablehand-held myotonometer.

METHODS

A total of 128 individuals (65 female, 63 male) who met the inclusion criteria were evaluated. Individuals were divided into 2 groups as under 40 years old (Group 1), and above (Group 2). The viscoelastic properties and muscle tone of orbicularis oris muscle were evaluated bilaterally in supine position with the Myoton PRO (Myoton AS, Estonia) device from the skin overlying the orbicularis oris. The reference point is accepted as the right and left paramedial philtrum dimple. The statistical analysis was performed.

RESULTS

There was no statistically significant difference in the elasticity values of the right and left orbicularis oris muscles of the Group 1 and Group 2 individuals. There was a difference between the groups when the tone and stiffness values of both groups were compared. It was determined that individuals over the age of 40 had higher muscle tone and stiffness. All mechanical properties of the superior orbicularis oris muscle between the male and female individuals in Group 1 were different. The values are higher in the female gender. The elasticity values in both genders in Group 2 were similar. Tone and stiffness parameters were different between genders.

CONCLUSIONS

Myoton PRO can be recommended as an alternative device in the quantitative evaluations of post-operative follow-ups, and pre/post rehabilitation in terms of viscoelastic parameters of the muscle.

Structural and mechanical properties of the Achilles tendon in senior badminton players: Operated vs. non-injured tendons

BACKGROUND

The aim of this study was to describe the differences in structural and mechanical properties between operated and non-injured Achilles tendons in senior badminton players who had had Achilles tendon surgery and had returned to play.

METHODS

Eighteen players (age = 48.9(10.0)years), assigned to the unilateral Achilles tendon rupture group and 177 non-injured players (age = 55.4(9.4)years), assigned to the control group. A Logiq®S8 ultrasound was used to study tendon structure and elastography index values and a Myoton®PRO hand-held myotonometer was used to record the stiffness of the Achilles tendon.

FINDINGS

In Achilles tendon rupture group, operated tendons showed higher values than non-injured ones in thickness (Operated = 9.03(2.67)mm vs. non-injured = 5.88(0.88)mm; P < 0.001), width (Operated = 18.44(3.20)mm vs. non-injured = 16.80(1.97)mm; P = 0.039), cross sectional area (Operated = 140.33(60.29)mm² vs. non-injured = 74.40(17.09)mm²; P < 0.001) and elastography index (Operated = 2.05(1.35)A.U. vs. non-injured = 1.47(0.62)A.U.; P = 0.025). The bilateral differences shown by the Achilles tendon rupture group were greater than the bilateral differences shown by the control group for thickness (P < 0.001), width (P = 0.001), cross sectional area (P < 0.001), tone (P = 0.006) and dynamic stiffness (Achilles tendon rupture group = 10.85(23.90)N∙m^-1. vs. control group = 0.18(18.83)N∙m^-1; P = 0.031).

INTERPRETATION

Surgery on the Achilles tendon and adaptation to the mobilisation and strength training during rehabilitation could provoke structural and mechanical differences compared to the non-injured tendon. Furthermore, the differences between both Achilles tendons in the Achilles tendon rupture group was higher than the asymmetry observed between dominant and non-dominant Achilles tendons in the control group. In addition, the higher logarithmic decrement values showed by non-injured tendons in the Achilles tendon rupture group could be a tendinous injury risk factor.

Treatment of Achilles Tendinopathy in Recreational Runners with Peritendinous Hyaluronic Acid Injections: A Viscoelastometric, Functional, and Biochemical Pilot Study

BACKGROUND

Achilles tendinopathy (AT) affects ca. 10 million recreational runners in Europe; the practice of hyaluronic acid (HA) infiltration is being increasingly adopted. The aim of this pilot study was to monitor the effects of a three-local time-spaced injections regimen of HA in the treatment of AT in middle-aged runners combining for the first time viscoelastometric, biochemical, and functional methodologies with routine clinical examinations.

METHODS

Eight male runners (Age 49.3 ± 3.9), diagnosed for unilateral AT, were given three ultrasound (US) guided peritendinous HA injections at the baseline (T0) and every fifteenth day with a follow-up on the forty-fifth day (T1, T2, and T3). At all-time points patients were assessed for viscoelastic tone and stiffness, maximal voluntary isometric contraction (MVIC), and pain level (Likert scale 0-5). The peritendinous effusions of the injured tendon were collected at T0 and T2 to quantify the volume variations and the IL-1β and MMP-3 levels.

RESULTS

At T0 MVIC and pain score were significantly lower and higher, respectively, in injured tendons. The volume, IL-1β and MMP-3 levels decreased in the course of treatment and the clinical endpoints ameliorated over time. Tone, stiffness, and functional performance also varied significantly at T2 and T3, as compared to T0.

CONCLUSIONS

The sequential peritendinous injections of HA were effective in the amelioration of the clinical symptoms, as well as of the functional and viscoelastic state associated with AT. The determination of the viscoelastometric state may help to precisely evaluate the healing process in AT patients.

An Interdisciplinary Examination of Stress and Injury Occurrence in Athletes

This paper adopts a novel, interdisciplinary approach to explore the relationship between stress-related psychosocial factors, physiological markers and occurrence of injury in athletes using a repeated measures prospective design. At four data collection time-points, across 1-year of a total 2-year data collection period, athletes completed measures of major life events, the reinforcement sensitivity theory personality questionnaire, muscle stiffness, heart rate variability and postural stability, and reported any injuries they had sustained since the last data collection. Two Bayesian networks were used to examine the relationships between variables and model the changes between data collection points in the study. Findings revealed muscle stiffness to have the strongest relationship with injury occurrence, with high levels of stiffness increasing the probability of sustaining an injury. Negative life events did not increase the probability of injury occurrence at any single time-point; however, when examining changes between time points, increases in negative life events did increase the probability of injury. In addition, the combination of increases in negative life events and muscle stiffness resulted in the greatest probability of sustaining an injury. Findings demonstrated the importance of both an interdisciplinary approach and a repeated measures design to furthering our understanding of the relationship between stress-related markers and injury occurrence.

Effect of diacutaneous fibrolysis on the muscular properties of gastrocnemius muscle

Diacutaneous fibrolysis is a noninvasive technique that has been shown to be effective in the treatment of musculoskeletal disorders such as shoulder pain, lateral epicondylalgia, patellofemoral pain syndrome and carpal tunnel syndrome. However, while diacutaneous fibrolysis is applied to soft tissue, its effects on muscular properties are unknown. The purpose of the present study was to evaluate the effects of diacutaneous fibrolysis on muscle properties as measured by tensiomyography and myotonometry in asymptomatic subjects. An analytical descriptive study was performed. A single session of diacutaneous fibrolysis on the gastrocnemius muscle was applied to one limb (treated limb group) and the other limb was the control (control limb group). Subjects were assessed with tensiomyography and myotonometry before treatment (T0), after treatment (T1) and 30 minutes later (T2). The primary outcomes were tensiomyography and myotonometry variables. The treated limb group showed a statistically significant increase (p<0.05) in tensiomyography parameters. A decrease in rigidity and increase in relaxation was also observed on myotonometry at T1, with some of the effects being maintained at T2. Rigidity and relaxation at T1 were statistically significant between groups (p<0.05). A single session of diacutaneous fibrolysis to the gastrocnemius muscle of asymptomatic subjects produced immediate changes in muscle properties. These changes were maintained 30 minutes after the application of the technique.

Eccentric Exercise Reduces Upper Trapezius Muscle Stiffness Assessed by Shear Wave Elastography and Myotonometry

In this study, we tested the hypotheses that unaccustomed eccentric exercise (ECC) would reduce the elastic modulus and dynamic stiffness of the upper trapezius muscle and that these changes would correlate with increases in muscle thickness, reflecting muscle edema. Shear wave elastography was used to measure elastic modulus, dynamic stiffness was assessed using myotonometry, and muscle thickness was measured using ultrasonography. All measurements were performed at four locations over the upper trapezius before and 24 h after a single bout of ECC. Fourteen healthy participants (11 males and 3 females; 23.2 ± 3.0 years; height 175.1 ± 10.4 cm; body mass 73.8 ± 11.3 kg) took part in the study. Overall, ECC resulted in decreased elastic modulus (from 45.8 ± 1.6 to 39.4 ± 1.2 kPa, p < 0.01) and dynamic muscle stiffness (from 369.0 ± 7.3 to 302.6 ± 6.0 N/m, p < 0.01). Additionally, ECC resulted in increased muscle thickness (from 6.9 ± 0.4 to 7.3 ± 0.4 mm, p < 0.01). Spatial changes (across the four locations) were found for elastic modulus, stiffness and thickness. No significant correlations were found between changes in measures of muscle stiffness, or between changes in stiffness and changes in thickness. In conclusion, the present pilot study showed that ECC altered biomechanical muscle properties, reflected by decreased elastic modulus and dynamic muscle stiffness 24 h after ECC.

Myotonometry for the evaluation of Achilles tendon mechanical properties: a reliability and construct validity study

Objective

This study evaluates the intra-rater and inter-rater reliability of the MyotonPRO and its construct validity for the assessment of Achilles tendon stiffness.

Design

Reliability and construct validity study.

Methods

Forty healthy participants were assessed using the MyotonPRO by two raters on two different occasions. Tendon was evaluated in three different positions (relaxed, 0° plantarflexion and standing) and during different isometric contractions (range 0–3 kg). Reliability was calculated using intraclass correlation coefficient (ICC and 95% CI) standard error of measurement and minimal detectable change. Construct validity was evaluated between the different positions and the different contraction intensities using Friedman test.

Results

Intra-rater reliability was very high ICC_2,k 0.87–0.98. The reliability of the 0.5 kg contraction was moderate with an ICC_2,k of 0.59. Inter-rater reliability ranged from high to very high with an ICC_2,k of 0.76–0.86. The reliability of the 0.5 kg, 1 kg contraction and the standing position was moderate with an ICC_2,k of 0.55, 0.54 and 0.56 respectively. Inter-session reliability ranged from high to very high with an ICC_2,k of 0.70–0.89. The reliability of the 0.5 kg contraction was moderate with an ICC_2,k of 0.54. Construct validity was demonstrated between different contraction levels and different positions.

Conclusion

MyotonPRO is a reliable tool for the evaluation of Achilles tendon stiffness during different contraction levels and in different positions. Construct validity was supported by changes of tendon stiffness during the explored conditions. MyotonPRO can be implemented, as a ready to use device, in the evaluation of tendon tissue mechanical properties.

Patellar and Achilles Tendon Stiffness in Elite Soccer Players Assessed Using Myotonometric Measurements

Background:

Tendon overuse injuries are an issue in elite footballers (soccer players) and may affect tendon function. Achilles and patellar tendinopathy are the most frequent pathologies. Tendon stiffness, the relationship between the force applied to a tendon and the displacement exerted, may help represent tendon function. Stiffness is affected by training and pathology. Nevertheless, information regarding this mechanical property is lacking for elite soccer athletes.

Hypothesis:

Achilles and patellar tendon stiffness assessed using myotonometric measurements will be greater in elite soccer athletes than in control participants.

Study Design:

Cross-sectional study.

Level of Evidence:

Level 4.

Methods:

Forty-nine elite soccer athletes and 49 control participants were evaluated during the 2017 preseason. A handheld device was used to measure Achilles and patellar tendon stiffness. Dominant and nondominant limbs were assessed for both groups.

Results:

A significantly stiffer patellar tendon was found for both the dominant and the nondominant limb in the elite soccer athletes compared with the control group. Nevertheless, no differences were found in Achilles tendon stiffness between groups. When comparing between playing positions in soccer athletes, no significant differences were found for both tendons.

Conclusion:

Greater patellar tendon stiffness may be related to an improvement in force transmission during muscle contraction. On the other hand, it seems that after years of professional training, Achilles tendon stiffness does not change, conserving the storing-releasing function of elastic energy. The nonsignificant differences between positions may be attributable to the years of homogeneous training that the players underwent.

Clinical Relevance:

The present study shows another technique for measuring mechanical properties of tendons in soccer athletes that could be used in clinical settings. In the future, this technique may help clinicians choose the best exercise protocol to address impairments in tendon stiffness.

Body Mass Index in Master Athletes: Review of the Literature

Background

Masters athletes (MAs) have led a physically active lifestyle for an extended period of time or initiated exercise/sport in later life. Given the benefits of physical activity and exercise we investigated if body mass index (BMI), an indirect health indicator of obesity, was clinically superior in MAs as compared to controls or the general population.

Methods

Seven databases (Medline, PubMed, Scopus, Web of Science, CINAHL, PsycINFO, Cochrane) were electronically searched for studies on BMI (kg/m²) or as a percentage of BMI categories (underweight, normal, overweight, obesity) in MAs.

Results

Of the initial yield of 7,431 papers, 60 studies met our inclusion criteria and were used in this literature review. Studies identified were classified as: endurance sports (n = 14), runners (n = 14), mixed sports (n = 8), cyclists (n = 4), soccer (n = 4) swimmers (n = 3), non-specific (n = 3), orienteering (n = 2), World Masters Games (n = 2) and individual sports (n = 5). Where BMI was presented for the group of MAs the mean was 23.8 kg/m² (± 1.1) with a range from 20.8 kg/m² (endurance runners) to 27.3 kg/m² (soccer players), this was significantly lower (p < 0.001) than controls ( −9.5%, 26.13 ± 1.7 kg/m²). Where gender specific BMI was reported the mean for male MAs was 23.6 kg/m² (± 1.5) (range 22.4 kg/m² endurance to 26.4 kg/m² swimmers) and 22.4 kg/m² (± 1.2) for female MAs (range 20.8 kg/m² mixed to 24.7 kg/m² WMG).

Conclusion

In most, but not all studies the BMI of MAs was significantly lower than controls. A clinically superior BMI affords MAs reduced risk with regard to a number of cardiometabolic diseases, osteoarthritis and certain types of cancers.

Assessment of Passive Stiffness of Medial and Lateral Heads of Gastrocnemius Muscle, Achilles Tendon, and Plantar Fascia at Different Ankle and Knee Positions Using the MyotonPRO

Background

The aim of this study was to assess the passive stiffness of the medial and lateral gastrocnemius (MG and LG), Achilles tendon (AT), and plantar fascia (PF) at different ankle and knee positions.

Material/Methods

Stiffness was assessed using a portable hand-held device (MyotonPRO). In 30 healthy participants (15 males, 15 females) with the knee fully extended or flexed 90°, stiffness of the MG, LG, AT, and PF was measured at 50° plantar flexion, 0° (neutral position), and 25° dorsiflexion (not for AT) of the ankle joint by passive joint rotation.

Results

With the knee fully extended, passive dorsiflexion caused significant increase in muscle stiffness (P<0.001), whereas AT and PF stiffness increased with passive ankle dorsiflexion regardless of knee position (P<0.001). Increased stiffness was observed in MG compared to LG (P<0.001) and at the 3-cm site of AT compared to the 6-cm site (P<0.05). Stiffness was greater in LG compared to MG at −50° plantar flexion (P<0.001) and was greater in MG compared to LG at 25° dorsiflexion (P<0.05). Stiffness of AT increased in a distal-to-proximal pattern: 0 cm >3 cm >6 cm (P<0.001).

Conclusions

Stiffness assessed by use of the MyotonPRO was similar assessments using other techniques, suggesting that the MyotonPRO is capable of detecting the variations in stiffness of MG, LG, AT, and PF at different ankle and knee positions.

Muscle and Bone Health in Postmenopausal Women: Role of Protein and Vitamin D Supplementation Combined with Exercise Training

Menopause is an age-dependent physiological condition associated with a natural decline in oestrogen levels, which causes a progressive decrease of muscle mass and strength and bone density. Sarcopenia and osteoporosis often coexist in elderly people, with a prevalence of the latter in elderly women. The profound interaction between muscle and bone induces a negative resonance between the two tissues affected by these disorders worsening the quality of life in the postmenopausal period. It has been estimated that at least 1 in 3 women over age 50 will experience osteoporotic fractures, often requiring hospitalisation and long-term care, causing a large financial burden to health insurance systems. Hormonal replacement therapy is effective in osteoporosis prevention, but concerns have been raised with regard to its safety. On the whole, the increase in life expectancy for postmenopausal women along with the need to improve their quality of life makes it necessary to develop specific and safe therapeutic strategies, alternative to hormonal replacement therapy, targeting both sarcopenia and osteoporosis progression. This review will examine the rationale and the effects of dietary protein, vitamin D and calcium supplementation combined with a specifically-designed exercise training prescription as a strategy to counteract these postmenopausal-associated disorders.

Quantifying the Stiffness of Achilles Tendon: Intra- and Inter-Operator Reliability and the Effect of Ankle Joint Motion

Background

The objectives of the present study were to examine the intra- and inter-operator reliability of the MyotonPRO device in quantifying the stiffness of the Achilles tendon and the device’s ability to examine the modulation in stiffness of the Achilles tendon during ankle joint flexion.

Material/Methods

Twenty asymptomatic participants (10 males and 10 females; mean age: 25.0±3.1 years) were recruited for this study. The stiffness of the Achilles tendon was quantified using the MyotonPRO device.

Results

The results revealed excellent intra- and inter-operator reliability for quantifying Achilles tendon stiffness with the ankle joint in a neutral position and detected a 13.9% increase in stiffness of the Achilles tendon between 0° and 30° of ankle joint flexion. The minimal detectable change (MDC) in tendon stiffness was 45 Newton/meter (N/m).

Conclusions

Our findings indicated that the MyotonPRO device is a feasible method to quantify the stiffness of the Achilles tendon and monitor its changes. Thus, it is an essential tool to use to examine the modulation in the stiffness of the Achilles tendon due to pathology or interventions for future studies.