Association between expiratory mouth pressure and abdominal muscle activity in healthy young males.

PURPOSE: To clarify the association between forced expiration and the abdominal muscles by assessing the relationship between expiratory mouth pressure and abdominal muscle activity in healthy young males. METHODS: Twenty-five males underwent forced expiration at 20, 30, 50, 75, and 100% of the maximal expiratory mouth pressure. Mouth pressure was measured using a bridge-type transducer connected to a mouth pressure meter. Abdominal crunch, twist crunch, and abdominal hollowing at maximal voluntary contraction were also performed. During forced expiration and abdominal exercises, the activity of the rectus abdominis (RA), oblique externus abdominis/oblique internus abdominis (OE/OI), and OI/transversus abdominis (OI/TrA) was measured using surface electromyography. RESULTS: The determination coefficient (r2) for the linear relationship between mouth pressure and abdominal muscle activity was 0.86 ± 0.15 for the RA, 0.93 ± 0.06 for the OE/OI, and 0.90 ± 0.14 for the OE/OI. The slope of the linear relationship with r2 ≥ 0.50 showed no significant difference between the RA (0.22 ± 0.27) and the OE/OI (0.27 ± 0.21). However, it was significantly greater in the OI/TrA (1.78 ± 1.41) than in the RA and OE/OI. The OE/OI activity was significantly lower in the maximal forced expiration than in twist crunch, and the OI/TrA activity was not significantly greater in the maximal forced expiration than in twist crunch. CONCLUSION: All abdominal muscles contribute to forced expiration with a greater contribution of the OI and TrA than the RA and OE. Furthermore, the contribution of the TrA would be greater than that of the OI.

Verification of surface electromyographic activity of the oblique externus abdominis using ultrasound shear wave elastography.

This study used ultrasound shear wave elastography (SWE) to revalidate whether surface electromyographic (EMG) electrodes placed on the oblique externus abdominis (OE) can detect only the OE activity without the confounding activity of the underlying oblique internus abdominis (OI). During left and right trunk rotations, the EMG activity was acquired using surface EMG electrodes placed on the right OE. Shear wave velocity (Vs ) values of the right OE and OI were acquired using SWE. The EMG activity during the left and right trunk rotations significantly increased as the level of exertion increased (25%, 50%, 75%, and 100% of the one-repetition maximum [1RM]). The Vs of the right OE was significantly different only between 25% and 75% 1RM in the right trunk rotation, but significantly increased from 25% to 75% 1RM during the left trunk rotation. The Vs of the right OI during the right trunk rotation significantly increased with increased levels of exertion, except between 50% and 75% 1RM. The results for the Vs of the OE and OI in the right trunk rotation suggest that surface EMG electrodes placed on the OE would detect not only the antagonistic OE activity but also the agonistic OI activity.

A case of polyangiitis overlap syndrome of giant cell arteritis and granulomatosis with polyangiitis successfully treated with rituximab.

We report a case of polyangiitis overlap syndrome of giant cell arteritis (GCA) and granulomatosis with polyangiitis (GPA) and conduct a literature review of polyangiitis overlap syndrome. The patient was 73-year-old male who developed cranial-type GCA and GPA simultaneously and was successfully treated with rituximab. Rituximab might be effective for not only GPA but also GCA.

Tocilizumab monotherapy for polymyalgia rheumatica: A prospective, single-center, open-label study.

OBJECTIVES: Polymyalgia rheumatica (PMR) is a systemic inflammatory disease in the elderly of unknown etiology. While glucocorticoids are the mainstay of treatment for PMR, various glucocorticoid-related adverse events are common. Recently, several studies have reported the efficacy of tocilizumab (TCZ), an anti-interleukin-6 receptor antibody, for PMR treatment in addition to an accompanying reduction, or even tapering-off, of glucocorticoids in some cases. The objective of this study was to elucidate the efficacy of TCZ monotherapy in the absence of glucocorticoids for PMR. METHOD: We conducted a 2-year, prospective, single-center, open-label pilot study of TCZ monotherapy in patients with PMR. TCZ (8 mg/kg) was administered at fortnightly intervals for the first 2 months and monthly over the next 10 months. Subsequently, patients were observed for another year without any treatment. The primary endpoints were the remission rates at weeks 12 and 52, and the secondary endpoints were the relapse rate and safety over the total 104 weeks. RESULTS: Thirteen patients were included in this study. Four of these patients achieved remission at week 12 (remission rate 31%). Four patients withdrew from the study due to adverse events (n = 2) and inefficacy (n = 2). At week 52, all 9 patients who had completed the first year achieved remission. Eight patients completed the drug-free second year, with 7 maintaining remission. CONCLUSIONS: TCZ monotherapy is well tolerated and can lead to remission in most patients with PMR in the absence of glucocorticoids.

Effective Timing of Curcumin Ingestion to Attenuate Eccentric Exercise-Induced Muscle Soreness in Men.

Curcumin is known to have potent anti-inflammatory effects. We have reported that acute curcumin ingestion attenuates eccentric exercise-induced muscle damage. This study aimed to examine the effect of curcumin ingestion timing (before or after exercise) on the changes in muscle damage markers after eccentric exercise. In this randomized, single-blind, parallel design study, 24 healthy young men performed 30 maximal isokinetic (120º/s) eccentric contractions of the elbow flexors using an isokinetic dynamometer. Subjects were randomly assigned to ingest 180 mg/d of oral curcumin either 7 d before (PRE) or 4 d after exercise (POST) or 180 mg/d of oral placebo 4 d after exercise (CON). The maximal voluntary contraction (MVC) torque of the elbow flexors, elbow joint range of motion (ROM), muscle soreness, and serum creatine kinase (CK) activity were measured before, immediately after, and 1-4 d after exercise. Changes in these variables were compared over time. In the POST group, ROM were higher at 3-4 d and muscle soreness was lower at 3 d after exercise compared with the CON group (p<0.05). However, in the PRE group, there were no significant differences compared with the CON group in changes in ROM and muscle soreness. Meanwhile, there were no significant differences among the groups in terms of changes in MVC torque and serum CK activity. Our results suggest that curcumin ingestion after exercise had a more beneficial effect in attenuating muscle soreness.

Effect of toe dorsiflexion on the regional distribution of plantar fascia shear wave velocity.

BACKGROUND: The plantar fascia is exposed to repetitive tensile stress induced by cyclic loads associated with daily activities, such as walking and running. Due to overuse or abnormal foot alignment, insertional and distal (i.e., mid-substance) regions within the plantar fascia may exhibit microtears, which leads to plantar fasciopathy. Ultrasound shear wave elastography is an imaging technique to measure shear wave velocity propagating through biological tissues, considered herein as an index of tensile stress. This study aimed to quantify the effect of toe dorsiflexion on the regional distribution of plantar fascia shear wave velocity. METHODS: Shear wave velocity of the plantar fascia was measured in the insertional and distal regions using ultrasound shear wave elastography in sixteen healthy participants (7 males and 9 females). The measurements were performed while the toes were maintained in neutral or dorsiflexed positions. FINDINGS: When considering the insertional region, there was no significant difference in shear wave velocity between neutral toe position [mean (SEM): 5.4 (0.6) m/s] and dorsiflexed toe position [5.5 (0.5) m/s] (P = 0.88; effect size = 0.05). When considering the distal region, there was a significant difference in shear wave velocity between the neutral position [7.8 (0.4) m/s] and dorsiflexed position [9.9 (0.3) m/s] (P = 0.002; effect size = 0.88). The difference in shear wave velocity between the insertional and distal regions showed a large effect size for either neutral (P = 0.010; effect size = 0.75) or dorsiflexed toe position (P = 0.003; effect size = 0.86). INTERPRETATION: In contrast to clinical beliefs, these findings suggest that toe dorsiflexion induces non-homogeneous changes in tensile stress within the plantar fascia.

Effects of oral curcumin ingested before or after eccentric exercise on markers of muscle damage and inflammation.

We examined the effect of curcumin (CUR) ingestion before or after exercise on changes in muscle damage and inflammatory responses after exercise. We conducted two parallel experiments with different CUR ingestion timings using a double-blind crossover. In Exp. 1, ten healthy men ingested 180 mg d-1 of CUR or placebo (PLA) 7 days before exercise. In Exp. 2, ten other healthy men ingested 180 mg d-1 of CUR or PLA 7 days after exercise. They performed 30 maximal isokinetic (120°s-1 ) eccentric contractions of the elbow flexors using an isokinetic dynamometer, and this was repeated with the other arm ≥4 weeks later. Maximal voluntary contraction (MVC) torque of the elbow flexors, elbow joint range of motion (ROM), muscle soreness, and serum creatine kinase (CK) activity were measured before, immediately after, and 1-7 days after exercise. Plasma interleukin-8 (IL-8) was measured before, immediately after, 12 hours after, and 1-7 days after exercise. The changes were compared over time. In Exp. 1, no significant differences were found between CUR and PLA subjects for each parameter. However, increases in IL-8 were significantly reduced 12 hours after exercise when CUR was ingested before exercise. In Exp. 2, compared to the PLA subjects, MVC torque and ROM were higher 3-7 days and 2-7 days after exercise (P < 0.05), respectively, whereas muscle soreness and CK activity were lower 3-6 days and 5-7 days after exercise (P < 0.05), respectively, in CUR subjects. CUR ingestion before exercise could attenuate acute inflammation, and after exercise could attenuate muscle damage and facilitate faster recovery.

Influence of pennation angle on measurement of shear wave elastography: in vivo observation of shear wave propagation in human pennate muscle.

OBJECTIVE: To examine the influence of pennation angle on measurement of shear wave elastography, this study utilised the propagation view mode that can reveal shear wave propagation in human pennate muscle in vivo. APPROACH: The validity of the propagation view mode was qualitatively confirmed by observation of shear wave propagation in tissue-mimicking phantoms. Shear wave velocity of the medial gastrocnemius (MG) was evaluated in 15 healthy males. By changing the placement of the ultrasound probe on the skin surface, shear wave propagation in the MG was changed: shear waves propagated along the MG fascicles (horizontal condition) and across the fascicles (oblique condition). MAIN RESULTS: It was observed that shear wave propagation became faster when shear waves passed through stiffer parts of the phantoms and perimysium of the MG, which is concordant with the basic principle of shear wave elastography. Shear wave velocity in the horizontal condition (2.69 ± 0.71 m s-1) was significantly higher than that in the oblique condition (2.61 ± 0.73 m s-1) (p < 0.001), but the effect size was small (Cohen's d = 0.11). SIGNIFICANCE: Ultrasound shear wave elastography can evaluate tissue elasticity of pennate muscles along the fascicle direction, even if shear waves propagate across the obliquely arranged fascicles.

Diaphragmatic shear modulus at various submaximal inspiratory mouth pressure levels.

This study assessed the shear modulus of the diaphragm at various submaximal inspiratory mouth pressure levels by ultrasound shear wave elastography. In 14 healthy male subjects, diaphragmatic shear moduli were assessed at end expiration during resting breathing and at submaximal inspiratory tasks at 15, 30, 45, 60, and 75% of the maximal inspiratory mouth pressure. The shear modulus increased along with mouth pressure, and the mouth-pressure-shear-modulus relationship fit the second-order polynomial regression equation (r2 = 0.99 ±â€¯0.01; all subjects, r2 ≥ 0.95) better than it did the simple linear regression equation (r2 = 0.94 ±â€¯0.05; 8/14 subjects, r2 ≥ 0.95). The second regression coefficient in the second-order polynomial equation was a negative value in 10 of 14 subjects, which indicates that the second-order polynomial regression equation opened downwards. These findings suggest that the diaphragmatic shear modulus increases along with inspiratory mouth pressure, but the rate of increase slows when the pressure reaches higher levels.

Muscle Thickness and Passive Muscle Stiffness in Elite Athletes: Implications of the Effect of Long-Term Daily Training on Skeletal Muscle.

To examine the effect of long-term daily training on athletes' skeletal muscle, this study determined the relation between their muscle thickness and passive muscle stiffness, and compared the muscle thickness and muscle stiffness between athletes and non-athletes. Participants were elite Japanese athletes (278 men, 200 women) from various sports and non-athletes (35 men, 35 women). Rectus femoris (RF) muscle thickness was measured using B-mode ultrasonography and was normalized to the total body mass (muscle thickness/body mass1/3). RF passive muscle stiffness (shear modulus) was assessed by ultrasound shear-wave elastography. There was a negligibly significant correlation between muscle thickness and muscle stiffness in male athletes (p=0.003; r=-0.18) but not in female athletes (p=0.764; r=0.02). Among men, muscle thickness was significantly greater in athletes than non-athletes (p<0.001), whereas muscle stiffness was significantly less in athletes than non-athletes (p=0.020). Among women, muscle thickness was significantly greater in athletes than non-athletes (p<0.001), whereas muscle stiffness did not differ significantly between athletes and non-athletes (p=0.412). These results suggest that the effect of long-term daily training performed by athletes on muscle stiffness is more complicated than that on muscle thickness.

Efficacy and tolerability of six-week extended dosing interval with tocilizumab therapy in a prospective cohort as remission maintenance in patients with rheumatoid arthritis.

OBJECTIVES: To prospectively evaluate the efficacy and tolerability of a six-week extended dosing interval with tocilizumab (TCZ) in patients with rheumatoid arthritis (RA) in sustained remission. METHODS: Patients who received over six doses of intravenous TCZ in clinical remission (disease activity score [DAS] 28 - erythrocyte sedimentation rate [ESR] ≤ 2.6) maintained over 3 months between December 2013 and December 2015 were included. Flare was defined as DAS28-ESR >3.2 at two consecutive visits. RESULTS: Twenty-five patients were enrolled; 87.5% achieved clinical remission at week 54 after six-week extension and 95.5% achieved a van der Heijde modified total Sharp score (ΔmTSS) ≤0.5. The Health Assessment Questionnaire Disability Index (HAQ-DI) did not increase during 54 weeks. HAQ-DI at baseline and ΔDAS28-ESR at week six positively correlated with increase in DAS28-ESR at week 54. ΔSwollen joint count at week six positively correlated with ΔmTSS at week 54. A total of 12 adverse events occurring in 10 patients did not lead to cessation of TCZ except for one case of recurrent lymphoproliferative disorder at week five. CONCLUSION: A six-week extended dosing interval of TCZ for patients with RA in sustained remission is proposed as an acceptable treatment option for maintaining efficacy and tolerability.

Association of Gastrocnemius Muscle Stiffness With Passive Ankle Joint Stiffness and Sex-Related Difference in the Joint Stiffness.

Passive ankle joint stiffness is affected by all structures located within and over the joint, and is greater in men than in women. Localized muscle stiffness can be assessed by ultrasound shear wave elastography, and muscle architecture such as fascicle length and pennation angle can be measured by B-mode ultrasonography. Thus, the authors assessed localized muscle stiffness of the medial gastrocnemius (MG) with consideration of individual variability in the muscle architecture, and examined the association of the muscle stiffness with passive ankle joint stiffness and the sex-related difference in the joint stiffness. Localized muscle stiffness of the MG in 16 men and 17 women was assessed at 10° and 20° plantar flexion, neutral anatomical position, and 10° and 20° dorsiflexion. Fascicle length and pennation angle of the MG were measured at these joint positions. Passive ankle joint stiffness was determined by the ankle joint angle-torque relationship. Localized MG muscle stiffness was not significantly correlated with passive ankle joint stiffness, and did not show significant sex-related difference, even when considering the muscle architecture. This finding suggests that muscle stiffness of the MG would not be a prominent factor in determining passive ankle joint stiffness and the sex-related difference in the joint stiffness.

Current clinical evidence of tocilizumab for the treatment of ANCA-associated vasculitis: a prospective case series for microscopic polyangiitis in a combination with corticosteroids and literature review.

The purpose of this study is to report the efficacy and safety of a combination of tocilizumab (TCZ) and high-dose corticosteroid (CS) in two patients with microscopic polyangiitis (MPA) and review the published current clinical evidence on TCZ in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV), except for large vessel vasculitis (LVV) and polymyalgia rheumatica (PMR). Two MPA patients were treated with TCZ at 8 mg/kg every month for 1 year and CS (prednisolone 1 mg/kg/day for 2 weeks, followed by tapering) in a prospective single-arm, single-center, cohort, open-label pilot study (UMIN clinical trials: 000012072). We performed a systematic literature search (PubMed and ICHUSHI [Japan Medical Abstracts Society] until June 30, 2017) to identify published reports on patients with all vasculitis other than LVV/PMR, who were treated with TCZ. We successfully treated the first patient. However, the other patient had serious infection probably associated with the combination of TCZ and high-dose CS. The literature review identified 22 reports with a total of 34 patients who received TCZ for AAV, rheumatoid vasculitis, and other types of vasculitis, in addition to our patients. In 15 of 17 patients (88.2%) with primary and secondary AAV, especially MPA, TCZ induced clinical remission, although TCZ use for rheumatoid vasculitis and vasculitis with mucocutaneous lesions is controversial. This study suggested that TCZ therapy is a potential treatment strategy for patients with AAV. However, TCZ combined with high-dose of CS might not be an appropriate treatment. Future studies are needed to confirm our findings.

Maximal inspiratory mouth pressure in Japanese elite female athletes.

Maximal inspiratory mouth pressure (MIP) is a common measurement of inspiratory muscle strength, which is often used in a variety of exercises to evaluate the effects of inspiratory muscle training. The characteristics of MIP in elite female athletes remain unclear. This study aimed to determine the characteristics of MIP at rest in a variety of sport-specific elite female athletes. We also aimed to clarify if there is a sex difference of MIP in elite athletes. We studied 169 Japanese elite female athletes and 301 Japanese elite male athletes. MIP was assessed using a portable autospirometer with a handheld mouth pressure meter. Female athletes who regularly experienced exercise-induced inspiratory muscle fatigue tended to have higher MIP values. The mean absolute MIP value in females was significantly lower than that in males. However, when this value was expressed relative to body mass, this difference disappeared. Our findings provide essential information for prescribed, sport-specific, inspiratory muscle training in elite female athletes.

Tissue elasticity of in vivo skeletal muscles measured in the transverse and longitudinal planes using shear wave elastography.

The aim of the present study was to measure in vivo skeletal muscle elasticity in the transverse and longitudinal planes using shear wave elastography and then to compare the image stability, measurement values and measurement repeatability between these imaging planes. Thirty-one healthy males participated in this study. Tissue elasticity (shear wave velocity) of the medial gastrocnemius, rectus femoris, biceps brachii and rectus abdominis was measured in both the transverse and longitudinal planes using shear wave elastography. Image stability was evaluated by the standard deviation of the colour distribution in the shear wave elastography image. Measurement repeatability was assessed by the coefficient of variance obtained from three measurement values. Image stability of all tested muscles was significantly higher in the longitudinal plane (P<0·001), but measurement repeatability did not differ significantly between the imaging planes (P>0·05), except in the biceps brachii (P = 0·001). Measurement values of the medial gastrocnemius, rectus femoris and biceps brachii were significantly different between the imaging planes (P<0·001). Image stability and measurement values of shear wave elastography images varied with imaging plane, which indicates that imaging plane should be considered when measuring skeletal muscle tissue elasticity by shear wave elastography.

Handheld Tissue Hardness Meters for Assessing the Mechanical Properties of Skeletal Muscle: A Feasibility Study.

OBJECTIVES: The purpose of this study was to examine the feasibility of using handheld tissue hardness meters to assess the mechanical properties of skeletal muscle. METHODS: This observational study included 33 healthy men (age, 22.4 ± 4.4 years) and 33 healthy women (age, 23.7 ± 4.2 years). Participants were placed in a supine position, and tissue hardness overlying the rectus femoris and the shear modulus of the muscle were measured on the right side of the body at 50% thigh length. In the same position, subcutaneous adipose tissue thickness and muscle thickness were measured using B-mode ultrasonography. To examine the associations of subcutaneous adipose tissue thickness, muscle thickness, and muscle shear modulus with tissue hardness, linear regression using a stepwise bidirectional elimination approach was performed. RESULTS: Stepwise linear regression revealed that subcutaneous adipose tissue thickness (r = -0.38, P = .002) and muscle shear modulus (r = 0.27, P = .03) were significantly associated with tissue hardness. CONCLUSIONS: Significant associations among adipose tissue thickness, muscle shear modulus, and tissue hardness show the limitations and feasibility of handheld tissue hardness meters for assessing the mechanical properties of skeletal muscles.

Maximal inspiratory mouth pressure in Japanese elite male athletes.

Maximal inspiratory mouth pressure (MIP) is a common measurement of inspiratory muscle strength, which is often used in a variety of exercises to evaluate the effects of inspiratory muscle training. An understanding of elite athletes' MIP characteristics is needed to guide sport-specific inspiratory muscle training programs. The purpose of this study was to investigate and better understand the MIP characteristics of elite athletes from a variety of sports. A total of 301 Japanese elite male athletes participated in this study. MIP was assessed using a portable autospirometer with a handheld mouth pressure meter. Athletes with higher body mass tended to have stronger MIP values, in absolute terms. In relative terms, however, athletes who regularly experienced exercise-induced inspiratory muscle fatigue tended to have stronger MIP values. Our findings suggest that athletes could benefit from prescribed, sport-specific, inspiratory muscle training or warm-ups.

Corticosteroid-free treatment of tocilizumab monotherapy for microscopic polyangiitis: a single-arm, single-center, clinical trial.

OBJECTIVES: To assess the efficacy of tocilizumab (TCZ) monotherapy for the remission induction of microscopic polyangiitis (MPA) in a prospective single-arm, single-center, cohort, pilot study. METHODS: Eligible patients were aged between 20 and 80 years and were newly diagnosed with MPA according to Watts' classification algorithm. Seven patients received 8 mg/kg of intravenous TCZ fortnightly for the first 2 months (5 courses), and monthly for the next 10 months (10 courses). One year after TCZ monotherapy, the patients were followed-up without any treatment. The protocol did not permit the use corticosteroids or any other immunosuppressants. Complete remission (CR) was defined as the Birmingham Vasculitis Activity Score of 0 at two consecutive visits made at least a month apart. RESULTS: CR was achieved in two of six patients (33.3%) at 6 months and three patients (50.0%) at 12 months. Two patients were withdrawn: one because of inefficacy at 6 weeks and the other because of flare at 6 months. One patient voluntarily withdrew after CR at 3 months. Four patients (66.7%) could be kept drug-free after 1 year of TCZ without relapse for 6-15 months at the last visit. CONCLUSION: TCZ monotherapy may be an alternative treatment strategy in some patients with MPA.

Measurement of gastrocnemius muscle elasticity by shear wave elastography: association with passive ankle joint stiffness and sex differences.

PURPOSE: Passive joint stiffness is an important quantitative measure of flexibility, but is affected by muscle volume and all of the anatomical structures located within and over the joint. Shear wave elastography can assess muscle elasticity independent of the influences of muscle volume and the other nearby anatomical structures. We determined how muscle elasticity, as measured using shear wave elastography, is associated with passive joint stiffness and patient sex. METHODS: Twenty-six healthy men (24.4 ± 5.9 years) and 26 healthy women (25.2 ± 4.8 years) participated in this study. The passive ankle joint stiffness and tissue elasticity of the medial gastrocnemius (MG) were quantified with the ankle in 30° plantar flexion (PF), a neutral anatomical position (NE), and 20° dorsiflexion (DF). RESULTS: No significant difference in passive joint stiffness by sex was observed with the ankle in PF, but significantly greater passive ankle joint stiffness in men than in women was observed in NE and DF. The MG elasticity was not significantly associated with joint stiffness in PF or NE, but it was significantly associated with joint stiffness in DF. There were no significant differences in MG elasticity by sex at any ankle position. CONCLUSIONS: Muscle elasticity, measured independent of the confounding effects of muscle volume and the other nearby anatomical structures, is associated with passive joint stiffness in the joint position where the muscle is sufficiently lengthened, but does not vary by sex in any joint position tested.

The association of muscle and tendon elasticity with passive joint stiffness: In vivo measurements using ultrasound shear wave elastography.

BACKGROUND: Passive joint stiffness is associated with various tissues, including muscles, tendons, ligaments, and joint capsules. The specific elasticity of muscles or tendons can be measured using ultrasound shear wave elastography. To examine the association of muscle and tendon elasticity with passive joint stiffness, in vivo measurements of muscle and tendon elasticity were performed using ultrasound shear wave elastography. METHODS: In 25 subjects, passive ankle joint stiffness was determined using the joint angle-passive torque relationship. The stiffness index of the muscle belly of the medial gastrocnemius (MG)--influenced by the muscle fascicles, its aponeuroses, and the proximal tendon--was quantified by the displacement of the muscle-tendon junction, which was visualized using B-mode ultrasonography during passive dorsiflexion. The stiffness index of the Achilles tendon--influenced by the tendon and the ligaments and joint capsule of the ankle--was similarly determined. The MG and Achilles tendon elasticity was measured using ultrasound shear wave elastography. FINDINGS: Simple regression indicated a significant correlation between passive joint stiffness and stiffness index of the MG muscle belly (r=0.80) and Achilles tendon (r=0.60), but no correlation with elasticity of the MG (r=-0.37) or Achilles tendon (r=-0.39). INTERPRETATION: Individual variations in the elasticity of either the MG or Achilles tendon are not associated with variations in passive ankle joint stiffness; however, variations in the elasticity of other tissues, including MG aponeuroses or the ligaments and joint capsule of the ankle, would be associated with the variations in joint stiffness.