Greater Muscle Stiffness during Contraction at Menstruation as Measured by Shear-Wave Elastography

Changes in the mechanical properties of the thigh and lower leg muscle-tendon units during the early follicular and early luteal phases

Background

This study aimed to determine changes in the muscle and tendon stiffness of the thigh and lower leg muscle-tendon units during the early follicular and early luteal phases, and check for possible relations between muscle and tendon stiffness in each phase.

Methods

The sample consisted of 15 female university students with regular menstrual cycles. The basal body temperature method, ovulation kit, and salivary estradiol concentration measurement were used to estimate the early follicular and early luteal phases. A portable digital palpation device measured muscle-tendon stiffness in the early follicular and early luteal phases. The measurement sites were the rectus femoris (RF), vastus medialis (VM), patellar tendon (PT), medial head of gastrocnemius muscle, soleus muscle, and Achilles tendon.

Results

No statistically significant differences in the thigh and lower leg muscle-tendon unit stiffness were seen between the early follicular and early luteal phases. Significant positive correlations were found between the stiffness of the RF and PT (r = 0.608, p = 0.016) and between the VM and PT (r = 0.737, p = 0.002) during the early luteal phase.

Conclusion

The present results suggest that the stiffness of leg muscle-tendon units of the anterior thigh and posterior lower leg do not change between the early follicular and early luteal phases and that tendons may be stiffer in those women who have stiffer anterior thigh muscles during the early luteal phase.

Monitoring of sprint and change of direction velocity, vertical jump height, and repeated sprint ability in sub-elite female football players throughout their menstrual cycle

AIMS

The aim of this study was to investigate the associations between the early follicular (EF, i.e., menstruation), late follicular (LF), and middle luteal (ML) phases of the menstrual cycle and different factors that may influence football performance.

METHODS

To this end, 11 eumenorrheic sub-elite female football players underwent field tests to assess sprint speed, lower extremity power, repeated sprint ability, velocity on change of direction, and technical skills at each cycle phase.

RESULTS

Performance during the 15-m change of direction ability test, 15-m ball dribbling test, squat jump height, total sprint time [sum of 7 sprints] and decrement score [(mean sprint time/best sprint time × 100) - 100], maximum and mean heart rate, and perceived exertion did not significantly differ among menstrual cycle phases. Conversely, the linear sprint velocity over 10, 20, 30-m distances was decreased in EF vs LF (10-, 20- and 30-m) and in ML vs LF (10- and 20-m) (p < 0.05). The 40-m sprint velocity did not change in the different menstrual cycle phases.

CONCLUSION

Overall, our study suggests that sex hormone fluctuations during the menstrual cycle are not associated with vertical jump, velocity on change of direction, and repeated sprint ability, but may influence linear sprint velocity over short distances (10, 20, and 30 m).

Oral Contraception Use and Musculotendinous Injury in Young Female Patients: A Database Study

PURPOSE

The purpose of this study is to characterize the effect of sex and the influence of oral contraception usage on musculotendinous injury (MTI). Current literature suggests a disparity in the incidence of MTI between males and females. This may be attributed to inherent biological differences between the sexes, such as in the sex hormonal milieu. There is a lack of information associating sex hormone milieu and MTI.

METHODS

We searched the PearlDiver database (a for-fee healthcare database) for males, females taking oral contraceptives (OC), and eumenorrheic females not taking any form of hormonal contraceptives (non-OC) 18-39 yr old. The three populations were matched by age and body mass index. We queried the database for lower-extremity skeletal MTI diagnoses in these groups.

RESULTS

Each group contained 42,267 patients with orthopedic injuries. There were a total of 1476 (3.49%) skeletal MTI in the male group, 1078 (2.55%) in non-OC females, and 231 (0.55%) in OC females. Both the non-OC and the OC groups had a significantly smaller proportion of MTI than males ( P < 0.0001), and therefore these groups were less likely (adjusted odds ratios, 0.72 and 0.15, respectively) to experience MTI when controlled for potential covariates.

CONCLUSIONS

In this study, we show that females are less likely to develop MTI to total injuries, when compared with males, with OC using females being least likely followed by non-OC females. These results are consistent with other epidemiological studies; however, overall results in the literature are variable. This study adds to the emerging body of literature on sex hormone-influenced musculoskeletal injury but, more specifically, MTI, which have not been rigorously investigated.

A retrospective comparison of the biceps femoris long head muscle structure in athletes with and without hamstring strain injury history

INTRODUCTION

Hamstring strain injuries (HSI) and re-injuries are endemic in high-speed running sports. The biceps femoris long head (BFlh) is the most frequently injured muscle among the hamstrings. Structural parameters of the hamstring muscle are stated to be susceptible to strain injuries at this location. This retrospective study targeted comparing the BFlh's structural parameters between previously injured and uninjured athletes.

METHODS

Nineteen male athletes with previous BFlh strain injury history and nineteen athletes without former lower extremity injury history were included in this study. Fascicle length, mid-muscle belly and distal musculotendinous (MTJ) passive stiffnesses of the biceps femoris long head (BFlh) were examined via b-mode panoramic ultrasound scanning and ultrasound-based shear-wave elastography. Parameter comparisons of both legs within and between athletes with and without injury history were performed.

RESULTS

Comparison of the BFlh fascicle length between the injured leg of the injured group and the legs of the controls revealed a trend to shorter fascicle lengths in the injured leg (p = 0.067, d = -0.62). However, the mid-muscle belly passive stiffness of the BFlh was significantly higher in the injured legs (p = 0.009, d = 0.7) compared with the controls. Additionally, the distal MTJ stiffness was much higher in the previously injured legs compared with controls (p < 0.001, d = 1.6).

CONCLUSIONS

Outcomes support the importance of BFlh properties related to stiffness, and fascicle length for injury susceptibility in athletes. Future prospective studies should determine whether the higher stiffness in the injured athletes is a cause or consequence of the HSI. Physical therapy and rehabilitation programmes after HSI should focus on BFlh muscle properties i.e., elasticity and fascicle length for reducing re-injury and increasing sports performance.

Acute Effects of Running on Shear Wave Elastography Measures of the Achilles Tendon and Calf Muscles in Professional Female Handball and Volleyball Players

Shear Wave Elastography (SWE) is currently used to detect tissue pathologies, i.e., tendinopathy. For preventive medicine, it is important to examine the sensitivity of SWE and to investigate how stiffness measures are affected by methodological variables. The aim of this study is to examine shear wave elastography (SWE) measures in order to compare the pre- and post-running values and to determine the correlation between the shear wave speed values (m/s). SWE examinations of the Achilles tendon (AT), soleus muscle (MS) and gastrocnemius muscle (MG)) were performed in 24 healthy professional female athletes. Measurements of the shear wave speed (m/s) were taken before and after incremental treadmill running until exhaustion. Correlations were investigated using the Pearson correlation coefficient and were examined for significance using the Student's t-test. The pre- and post-exercise shear wave speed did not differ. The pre-exercise and post-exercise stiffness for MS (r = 0.613), MG (r = 0.609) and AT (r = 0.583) correlated strongly. The pre-exercise values and changes in stiffness showed a significant correlation (p < 0.001). In professional athletes, acute exercise induces different tissue stiffness changes in AT, MS and MG for each individual. Thus, exercise activity immediately prior to the SWE measurement needs to be factored in when evaluating tissue stiffness.

Differences in Medial and Lateral Gastrocnemius Stiffness after Exercise-Induced Muscle Fatigue

Muscles are affected at the cellular level by exercised-induced fatigue, inducing changes in their stiffness. Examining muscle stiffness can improve the knowledge of various pathologic conditions, such as pain and injury. The objective of this study was to examine the stiffness of the medial gastrocnemius (MG) muscle and the lateral gastrocnemius (LG) muscle to determine the changes in stiffness, and to assess the differences in the stiffness between the MG and the LG, as affected by muscle fatigue measured using shear wave elastography (SWE) and a MyotonPRO after inducing muscle fatigue. A total of 35 healthy young adults participated in the study. The stiffness of the MG and the LG were assessed before and after a muscle fatigue protocol (MFP), which included three sets of 50 eccentric contractions of the calf muscles of the dominant leg, at rest, and at maximum voluntary contraction (MVC). The measurements were taken with SWE and the MyotonPRO simultaneously. Compared to baseline, the resting stiffness of the MG and the LG significantly increased immediately, 24 h, and 48 h after muscle fatigue (p < 0.05); however, during MVC, the stiffness of the MG decreased (p < 0.05) and that of the LG showed no change (p > 0.05). When the stiffness of the MG and the LG were compared before and after the MFP, changes in the stiffness of the MG were significantly greater than those in the LG (p < 0.05). This signifies that the MG was more affected by the exercise-induced muscle fatigue than was the LG. The assessment of musculoskeletal tissue and its characteristics, before and after eccentric exercise, is crucial in the prevention of overuse injuries associated with repeated exposure to both low and high levels of force.

Effects of Knee Joint Angle and Contraction Intensity on the Triceps Surae Stiffness

Purpose: Monitoring the contractility of muscles assists the clinician in understanding how muscle functions as part of the kinetic system. This study investigated the effect of knee joint angles under different resistance on the stiffness of the medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SOL) muscles using the shear wave elastography (SWE) technique.

Methods: A total of 22 females were recruited. During isometric plantar flexion, at knee 0-degree (fully extended) and knee 90-degree (flexed 90°), the shear modulus on the MG, LG, and SOL was measured by shear wave elastography at no contraction and two intensities (40% and 80%) of maximal voluntary contraction (MVC). Shear modulus is a mechanical parameter to describe stiffness, and stiffness is a proxy for muscle contractility.

Results: There were moderate-to high-positive correlations between the active stiffness of triceps surae muscles and isometric contraction intensity (r: 0.57–0.91, p＜0.001). The active stiffness in MG and LG with extended knees was higher than that with flexed knees (p＜0.001). The active stiffness in SOL with flexed knee was higher than that with extended knee (p＜0.001).

Conclusion: Active stiffness can be considered a quantitative indicator generated by the force output of the triceps surae. Different knee joint angles cause three triceps surae muscles to exhibit non-uniform mechanical properties, which may explain part of the mechanism of soft tissue injury during physical exercise.

The effects of eccentric exercise on passive hamstring muscle stiffness: Comparison of shear-wave elastography and passive knee torque outcomes

The aim of our study was to assess eccentric-exercise-induced changes in passive knee joint torque, passive knee joint stiffness and shear modulus at of the hamstring muscles. We hypothesized that eccentric exercise would elicit an increase in all outcomes. Fourteen healthy volunteers (age = 25.5±4.7 years) performed eccentric exercise protocol. Before and after 0h, 1h, 24h and 48h, we measured the shear modulus of hamstring muscles using shear-wave elastography and passive knee joint stiffness on isokinetic dynamometer. After eccentric exercise, the shear modulus of biceps femoris increased after 0h (22.4 ± 34.1 %; p = 0.021) and for semitendinosus after 0h (14.5 ± 4.9 %), 1h (16.2 ± 6.5 %) and 24h (16.6 ± 8.3 %) (p = 0.005-0.015). There were no changes for semimembranosus and no changes in passive knee joint moment measures. There were also no correlations between the two methods. Eccentric exercise increased shear modulus of hamstring muscles, while passive joint torque was not affected. This suggests that shear-wave elastography could be more sensitive than torque measures to intra-muscular changes induced by eccentric exercise.

Assessing the differences in muscle stiffness measured with shear wave elastography and myotonometer during the menstrual cycle in young women

This study assessed the differences in muscle stiffness of the medial gastrocnemius (MG) and tibialis anterior (TA) muscles at rest and contraction during ovulation and follicular phase (menstruation) in women with regular menstrual cycle. Thirty-four young healthy women (mean age 21.3 ± 1.3 years) with regular menstrual cycles participated in this study. Stiffness of the TA and MG muscles at rest and voluntary contraction during ovulation and follicular phase in young women were measured using shear-wave elastography (SWE) and the handheld myotonometer MyotonPRO. The absolute stiffness difference between resting and contraction was expressed as the stiffness increase rate (SIR). The stiffness of the MG and TA at the resting position was not significantly different between the two phases of the menstrual cycle (p > .05). A significantly greater stiffness of both muscles measured using MyotonPRO in the follicular phase than during ovulation was found (p < .05), while stiffness measured by SWE showed a difference only in the TA muscle during contraction (p < .05). In addition, there were no significant differences in the SIR of both muscles between the two phases (p > .05). The results of our study showed a significantly greater stiffness of the MG and TA muscles at the follicular phase than at ovulation during contraction only. As muscle stiffness affects the risk of injury owing to reduced stability during sports activities, these changes in mechanical properties during the menstrual cycle should be noted, and training strategies should be used in female athletes. This article is protected by copyright. All rights reserved.

The Influence of Menstrual Cycle on Bioimpedance Vector Patterns, Performance, and Flexibility in Elite Soccer Players

PURPOSE

To examine whether menstrual cycle affects body composition and bioimpedance vector analysis (BIVA) patterns, jumping and sprinting ability, and flexibility in elite soccer players.

METHODS

A total of 20 elite female soccer players (age: 23.8 [3.4] y, height: 1.63 [0.04] m, body mass: 61.4 [5.9] kg, and body mass index: 22.5 [2.4] kg/m2) were monitored during the early follicular and ovulatory phase across 2 consecutive menstrual cycles. Bioimpedance analysis was performed using foot-to-hand technology, and total body water and fat mass were determined by specific equations developed for athletes. Bioelectrical resistance and reactance were adjusted according to the BIVA procedures and plotted as a vector within the resistance-reactance graph. In addition, countermovement jump, 20-m sprint, and sit and reach were assessed.

RESULTS

A time effect (P < .05) was found for body mass, total body water, bioelectrical resistance and reactance, and flexibility. Specifically, body mass increased (P = .021) along with a gain in total body water (P = .001) from the ovulatory to the early follicular phase, while it decreased from the early follicular to the ovulatory phase during the second menstrual cycle. The BIVA vector shortened during the early follicular phases (P < .001). No change in jumping and sprinting capacity was observed (P > .05). Flexibility was impaired during the early follicular phases (P < .05).

CONCLUSIONS

Specific bioelectrical impedance analysis and BIVA procedures are able to detect menstrual cycle-induced changes in body composition in elite soccer players. The early follicular phase resulted in fluid accumulations and BIVA vector shortening. In addition, while menstrual cycle did not affect performance, a fluctuation in flexibility was observed.

Assessing the Effects of Aging on Muscle Stiffness Using Shear Wave Elastography and Myotonometer

The current study investigated the differences in muscle stiffness between older and young adults at rest and during contraction. We also evaluated the differences in muscle stiffness assessments using a myotonometer (MyotonPRO) and shear wave elastography (SWE). Twenty-two older adults (mean age, 66.6 ± 1.6 years) and 23 young adults (mean age, 66.6 ± 1.6 years) participated in this study. Muscle stiffness of the tibialis anterior (TA) and medial gastrocnemius (MG) muscles at rest and during contraction were measured using SWE and the MyotonPRO. The stiffness increase rate (SIR) was also calculated to determine the absolute stiffness difference. The mean muscle stiffness of the TA and MG muscles was significantly lower in older adults than in young adults at rest and during contraction (p < 0.05). Similarly, the SIR values of the TA and MG were significantly lower in older adults than in young adults (p < 0.05). Our results indicate that both instruments could be used to quantify muscle stiffness changes and serve as a cornerstone for assessing aging-related losses in muscle function. Stiffness measures may help exercise professionals to develop an in-depth understanding of muscle impairment at the tissue level.

Shear wave elastography detects novel imaging biomarkers of aromatase inhibitor-induced joint pain: a pilot study

Aim

To determine whether differences in joint and tendon stiffness as measured by ultrasound shear wave elastography are present in breast cancer patients with aromatase inhibitor-associated arthralgias compared to age-comparable healthy control women.

Methods

Postmenopausal women with stage I–III breast cancer who were taking adjuvant aromatase inhibitors and complained of joint pain were enrolled (n = 6). Postmenopausal women with no history of breast cancer, hormone treatment, or joint pain served as controls (n = 7). All subjects had bilateral hands and wrists evaluated by gray-scale and power Doppler ultrasound, and shear wave elastography ultrasound.

Results

Patients with AI-associated arthralgias had significantly stiffer tendons than controls in the 1^st extensor compartment (long axis; p = 0.001), 4^th extensor compartment (long axis; p = 0.014), 3^rd metacarpophalangeal joint (p = 0.002), the pooled values of the extensor compartments, both long (p = 0.044) and short axes (p = 0.035), and the pooled values for the metacarpophalangeal joints (p = 0.002). On ultrasound, the patients (but not controls) presented with hyperemia and increased tenosynovial fluid in the flexor and extensor tendon sheaths, and the median nerves were symptomatic and bifid; however, these differences were not statistically significant.

Conclusions

This is the first study to identify increased tendon stiffness as a putative physiological characteristic of aromatase inhibitor–associated arthralgias. Future studies should determine whether increased tendon stiffness is a risk factor for the development of aromatase inhibitor–associated arthralgias, or a result of aromatase inhibitor treatment.

A comparison of foam rolling and vibration foam rolling on the quadriceps muscle function and mechanical properties

Purpose

The purpose of the study was to investigate the effects of using a vibration foam roll (VFR) or a non-vibration foam roll (NVFR) on maximum voluntary isometric contraction peak torque (MVIC), range of motion (ROM), passive resistive torque (PRT), and shear modulus.

Methods

Twenty-one male volunteers visited the laboratory on two separate days and were randomly assigned to either a VFR group or a NVFR group. Both interventions were performed for 3 × 1 min each. Before and after each intervention, passive resistive torque and maximum voluntary isometric contraction peak torque of the leg extensors were assessed with a dynamometer. Hip extension ROM was assessed using a modified Thomas test with 3D-motion caption. Muscle shear modulus of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) was assessed with shear wave elastography (SWE).

Results

In both groups (VFR, NVFR) we observed an increase in MVIC peak torque (+ 14.2 Nm, + 8.6 Nm) and a decrease in shear modulus of the RF (− 7.2 kPa, − 4.7 kPa). However, an increase in hip extension ROM (3.3°) was only observed in the VFR group. There was no change in PRT and shear modulus of the VL and VM, in both the VFR group and the NVFR group. Our findings demonstrate a muscle-specific acute decrease in passive RF stiffness after VFR and NVFR, with an effect on joint flexibility found only after VFR.

Conclusion

The findings of this study suggest that VFR might be a more efficient approach to maximize performance in sports with flexibility demands.

Aptamer-Based Lateral Flow Biosensor for Rapid Detection of Salivary Cortisol

We have developed a disposable point-of-care (POC) aptamer-based biosensor for the detection of salivary cortisol. Nonstressful and noninvasive sampling of saliva compared to that of blood makes saliva an attractive biological matrix in developing POC devices for biomarker monitoring. Aptamers are attractive as recognition elements for multiple reasons, including their specific chemical synthesis, high stability, lack of immunogenicity, and cell-free evolution. A duplex aptamer conjugated to the surface of Au nanoparticles (AuNPs) by Au-S bonds is utilized as the sensor probe in a lateral flow assay (LFA) device. The addition of saliva samples containing cortisol makes the cortisol-aptamer undergo conformational changes and dissociate from the capture probe. Increasing cortisol concentration in the dispensed saliva sample results in increased dissociation and leads to increased binding of AuNP conjugate on the test line. Therefore, the color intensity of the test line on the LFA is a direct function of the concentration of cortisol in saliva. This simple and fast method provides detection in the cortisol range of ∼0.5-15 ng/mL, which is in the clinically accepted range for salivary cortisol. The limit of detection was 0.37 ng/mL, and the accuracy was confirmed by enzyme-linked immunosorbent assay (ELISA) testing results. High selectivity was observed for salivary cortisol against other closely related steroids and stress biomarkers present in saliva.

Development of Stiffness Measurement Program Using Color Mapping in Shear Wave Elastography

Shear wave elastography with ultrasound is a noninvasive method used for measuring stiffness in the human body. Shear wave elastography can be used for accurately and quantitatively measuring stiffness. However, its disadvantage is that the stiffness value can vary significantly because the region of interest (ROI) setting depends on the diagnostic operator. In this study, a stiffness measurement program using color mapping in shear wave elastography was developed to address the above-mentioned disadvantage. Color map and color ratios were obtained and evaluated for major lower limb muscles (i.e., biceps femoris, medial gastrocnemius, rectus femoris, and tibialis anterior) at active voluntary contraction. According to the result, when the developed program was used, a small standard deviation compared to the conventional stiffness measurement method, such as kilopascal or meter per second unit using ROIs, was measured in all cases. In conclusion, our results demonstrate that the stiffness measurement method using our program is expected to improve reliability in shear wave elastography ultrasound imaging.