Evaluating Renal Transplant Status Using Viscoelastic Response (VisR) Ultrasound

Chronic kidney disease is most desirably and cost-effectively treated by renal transplantation, but graft survival is a major challenge. Although irreversible graft damage can be averted by timely treatment, intervention is delayed when early graft dysfunction goes undetected by standard clinical metrics. A more sensitive and specific parameter for delineating graft health could be the viscoelastic properties of the renal parenchyma, which are interrogated non-invasively by Viscoelastic Response (VisR) ultrasound, a new acoustic radiation force (ARF)-based imaging method. Assessing the performance of VisR imaging in delineating histologically confirmed renal transplant pathologies in vivo is the purpose of the study described here. VisR imaging was performed in patients with (n?=?19) and without (n?=?25) clinical indication for renal allograft biopsy. The median values of VisR outcome metrics (τ, relative elasticity [RE] and relative viscosity [RV]) were calculated in five regions of interest that were manually delineated in the parenchyma (outer, center and inner) and in the pelvis (outer and inner). The ratios of a given VisR metric for all possible region-of-interest combinations were calculated, and the corresponding ratios were statistically compared between biopsied patients subdivided by diagnostic categories versus non-biopsied, control allografts using the two-sample Wilcoxon test (p?<0.05). Although τ ratios non-specifically differentiated allografts with vascular disease, tubular/interstitial scarring, chronic allograft nephropathy and glomerulonephritis from non-biopsied control allografts, RE distinguished only allografts with vascular disease and tubular/interstitial scarring, and RV distinguished only vascular disease. These results suggest that allografts with scarring and vascular disease can be identified using non-invasive VisR RE and RV metrics.     

Local Texture Anisotropy as an Estimate of Muscle Quality in Ultrasound Imaging

This study introduces local pattern texture anisotropy as a novel parameter to differentiate healthy and disordered muscle and to gauge the severity of muscle impairments based on B-mode ultrasound images. Preliminary human results are also presented. A local pattern texture anisotropy index (TAI) was computed in one region of interest in the short head of the biceps brachii. The effects of gain settings and box sizes required for TAI computation were investigated. Between-day reliability was studied in patients with sporadic inclusion body myositis (n?=?26). The ability of the TAI to discriminate dystrophic from healthy muscle was evaluated in patients with Duchenne muscular dystrophy and healthy controls (n?=?16). TAI values were compared with a gray-scale index (GSI). TAI values were less influenced by gain settings than were GSI values. TAI had lower between-day variability (typical error?=?2.3%) compared with GSI (typical error?=?2.3% vs. 8.3%, respectively). Patients with Duchenne muscular dystrophy had lower TAIs than controls (0.76?±?0.06 vs. 0.87?±?0.03, respectively, p?<0.05). At 40% gain, TAI values correlated with percentage predicted elbow flexor strength in inclusion body myositis (R?=?0.63, p?<0.001). The TAI may be a promising addition to other texture-based approaches for quantitative muscle ultrasound imaging.     

Performance of Passive Muscle Stiffness in Diagnosis and Assessment of Disease Progression in Duchenne Muscular Dystrophy

The aim of this study was to evaluate the performance of passive muscle stiffness in diagnosing and assessing disease progression in Duchenne muscular dystrophy (DMD). Boys with DMD and age-matched controls were recruited. Shear wave elastography (SWE) videos were collected by performing dynamic stretching of the gastrocnemius medius (GM). At ankle angles from plantar flexion (PF) 30° to dorsiflexion (DF) 20°, the shear modulus of the GM was measured for each 10° of ankle movement. Shear modulus at each ankle angle was compared between the DMD and control group. Correlation between passive muscle stiffness and motor function grading was also analyzed. A total of 26 patients with DMD and 20 healthy boys were enrolled. At multiple stretch levels, passive muscle stiffness of the GM was significantly higher in patients with DMD than in those in the control group (all p values <0.05). The shear modulus of GM at an ankle angle of DF 10° had the largest area under the receiver operating characteristic curve in differentiating DMD patients from normal subjects (AUC = 0.902, 95% confidence interval: 0.814–0.990). Motor function grading was a significant determinant of passive muscle stiffness at an ankle angle of DF 10° (B = 21.409, t = 3.372, p = 0.003). Passive muscle stiffness may potentially serve as a useful non-invasive tool to monitor disease progression in DMD patients.     

Sonoelastography of the trunk and lower extremity muscles in a case of Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a rare genetic disorder typically presenting with muscle weakness and reduced tone of trunk and lower extremities. The sonoelastographic properties of DMD are poorly understood. We describe sonoelastographic characteristics of a patient’s trunk and lower extremity musculature. An 8-year-old male presented with a 5-year history of DMD. Sonoelastographic measures of the gluteus maximus and medius, lumbar erector spinae, rectus abdominis, rectus femoris, biceps femoris, tibialis anterior, medial and lateral gastrocnemius muscles were obtained. Sonoelastography demonstrated increased elasticity by elevated kiloPascals (kPa) across all muscles, except the lumbar erector spinae. Patient values were compared to an age-matched healthy control. These abnormal sonoelastographic findings reflected the pathological mechanical properties of DMD. Sonoelastography was valuable for characterizing the mechanical properties of normal and abnormal muscle tissue. There is limited information on the sonoelastography application to DMD. Sonoelastography may serve as a useful measure for diagnosis and monitoring clinical outcomes for DMD.     

Regional contribution to ventricular stroke volume is affected on the left side,but not on the right in patients with pulmonary hypertension

To develop more sensitive measures of impaired cardiac function in patients with pulmonary hypertension (PH), since detection of impaired right ventricular (RV) function is important in these patients. With the hypothesis that a change in septal function in patients with PH is associated with altered longitudinal and lateral function of both ventricles, as a compensatory mechanism, we quantified the contributions of these parameters to stroke volume (SV) in both ventricles using cardiac magnetic resonance (CMR). Seventeen patients (10 females) evaluated for PH underwent right heart catheterization (RHC) and CMR. CMR from 33 healthy adults (13 females) were used as controls. Left ventricular (LV) atrioventricular plane displacement (AVPD) and corresponding longitudinal contribution to LVSV was lower in patients (10.8?±?3.2 mm and 51?±?12?%) compared to controls (16.6?±?1.9 mm and 59?±?9?%, p?<?0.0001 and p?<?0.01, respectively). This decrease did not differ in patient with ejection fraction (EF) >50?% and <50?% (p?=?0.5) and was compensated for by increased LV lateral contribution to LVSV in patients (49?±?13?% vs. 37?±?7?%, p?=?0.001). Septal motion contributed less to LVSV in patients (5?±?8?%) compared to controls (8?±?4?%, p?=?0.05). RV AVPD was lower in patients (12.0?±?3.6 mm vs. 21.8?±?2.2 mm, p?<?0.0001) but longitudinal and lateral contribution to RVSV did not differ between patients (78?±?17?% and 29?±?16?%) and controls (79?±?9?% and 31?±?6?% p?=?0.7 for both) explained by increased RV cross sectional area in patients. LV function is affected in patients with PH despite preserved global LV function. The decreased longitudinal contribution and increased lateral contribution to LVSV was not seen in the RV, contrary to previous findings in patients with volume loaded RVs.     

Quantifying Lower Limb Muscle Stiffness as Ambulation Function Declines in Duchenne Muscular Dystrophy with Acoustic Radiation Force Impulse Shear Wave Elastography

Duchenne muscular dystrophy (DMD) is a progressive muscular disease, but validated imaging tools to quantify muscle microstructure alteration as mobility declines are lacking. We aimed to determine the feasibility of using acoustic radiation force impulse shear-wave elastography (ARFI/SWE) in the quantitative assessment of lower limb muscle stiffness in DMD patients. Shear wave velocities (SWVs) of lower limbs were measured in 39 DMD patients and 36 healthy controls aged 3–20 y. Mean SWV values of the controls and of the DMD patients at different ambulatory stages were compared using analysis of variance with Bonferroni correction. The DMD group had increased lower limb muscle stiffness compared with controls. Stiffness of the tibialis anterior and medial gastrocnemius muscle decreased from ambulatory to early non-ambulatory stages, whereas stiffness of the rectus femoris muscle increased from ambulatory to late non-ambulatory stages. We describe how SWV changes in lower limb muscles have the potential to predict ambulatory decline in DMD.     

Multimodal exercise training during myeloablative chemotherapy: a prospective randomized pilot trial

Purpose

Cancer and its treatment-related side effects induce loss of physical performance. This study evaluated the effects of multimodal aerobic and strength exercises on physical performance in hospitalized cancer patients while receiving myeloablative chemotherapy.

Methods

In this prospective pilot study, 48 evaluable patients were randomly assigned to a training (TG, n?=?24) or control (CG, n?=?24) group. The TG performed an individually supervised exercise program five times a week with ergometer training and strength exercises for 20 min each during the hospitalization period for chemotherapy. The CG received standard physiotherapy. Physical performance was evaluated using spiroergometry, lung function, and muscle strength testing. Treatment-related side effects were assessed by daily interviews, quality of life by EORTC-QLQ-C30, and fatigue using the Modified Fatigue Impact Scale (MFIS) questionnaire.

Results

Physical performance significantly increased in the TG (8.96?±?24 W) and decreased in the CG (?7.24?±?20 W, p?=?0.02). At 2-mmol/ml blood lactate concentration, the TG achieved significantly increased oxygen consumption (p?=?0.03) and expiratory minute ventilation (p?=?0.04) compared to the CG. Furthermore, physical functioning increased significantly in the TG (p?=?0.04). Patients in the TG required less antiemetics (p?=?0.01) and experienced significantly less fatigue (p?=?0.04), although MFIS analysis was not able to detect this beneficial effect. Patients of the CG displayed higher impairments of cognitive (p?=?0.02) and psychosocial function (p?=?0.03) after chemotherapy. No adverse events due to the study intervention were observed.

Conclusions

Multimodal exercise has beneficial effects on physical performance, physical functioning, and treatment-related symptoms even during myeloablative chemotherapy. We suggest an enhanced physical activity intervention program during hospitalization of cancer patients.     

The effect of a supersaturated calcium phosphate mouth rinse on the development of oral mucositis in head and neck cancer patients treated with (chemo)radiation

Objectives

Mucosal damage is an important and debilitating side effect when treating head and neck cancer patients with (chemo-)radiation. The aim of this randomized clinical trial was to investigate whether the addition of a neutral, supersaturated, calcium phosphate (CP) mouth rinse benefits the severity and duration of acute mucositis in head and neck cancer patients treated with (chemo)radiation.

Materials and methods

A total of 60 patients with malignant neoplasms of the head and neck receiving (chemo)radiation were included in this study. Fifty-eight patients were randomized into two treatment arms: a control group receiving standard of care (n?=?31) and a study group receiving standard of care?+?daily CP mouth rinses (n?=?27) starting on the first day of (chemo-)radiation. Oral mucositis and dysphagia were assessed twice a week using the National Cancer Institute common toxicity criteria scale version 3, oral pain was scored with a visual analogue scale.

Results

No significant difference in grade III mucositis (59 vs. 71 %; p?=?0.25) and dysphagia (33 vs. 42 %, p?=?0.39) was observed between the study group compared to the control group. Also no significant difference in time until development of peak mucositis (28.6 vs. 28.7 days; p?=?0.48), duration of peak mucositis (22.7 vs. 24.6 days; p?=?0.31), recuperation of peak dysphagia (20.5 vs 24.2 days; p?=?0.13) and occurrence of severe pain (56 vs. 52 %, p?=?0.5).

Conclusion

In this randomized study, the addition of CP mouth rinse to standard of care did not improve the frequency, duration or severity of the most common acute toxicities during and early after (chemo)radiation. There is currently no evidence supporting its standard use in daily practice.     

杜氏肌营养不良与贝氏肌营养不良常规MRI的对比研究

目的 探讨常规MRI鉴别诊断杜氏肌营养不良（DMD）和贝氏肌营养不良（BMD）的价值。方法 回顾性分析经临床确诊为抗肌萎缩蛋白病697例患者的臀部及大腿肌肉影像学资料,比较DMD与BMD影像学征象的异同。结果 DMD与BMD患者肌肉脂肪浸润的分布规律一致,DMD总体脂肪浸润程度高于BMD（P=0.034）,且以臀大肌、股直肌、缝匠肌为著;肌肉总体水肿程度差异无统计学意义（P=0.065）,但DMD大腿后群肌肉及缝匠肌的水肿明显高于BMD。DMD与BMD患者肌肉萎缩及肥大的选择性受累规律一致,BMD股外侧肌、股中间肌、股内侧肌、半膜肌及股二头肌长头萎缩频率明显高于DMD（P<0.05）;DMD与BMD患者肌肉的肥大改变差异无统计学意义（P>0.05）。结论 常规MRI可鉴别诊断DMD与BMD。     

Clinical correlates of endothelial function in chronic heart failure

Objective

There is a close link between heart failure and endothelial dysfunction. Brachial flow-mediated dilation (FMD) is a validated non-invasive measure of endothelial function. The aim of this study was to investigate the clinical correlates of FMD in patients with chronic heart failure (CHF).

Design, setting, patients

We evaluated 60 CHF outpatients (age 62?±?14?years; 49 males, NYHA class 2.2?±?0.7, left ventricular ejection fraction, LVEF, 33?±?8%) taking conventional medical therapy (ACE-inhibitors and/or ARBs 93%, beta-blockers 95%) and in stable clinical conditions.

Main outcome measures

The maximum recovery value of FMD was calculated as the ratio of the change in diameter (maximum-baseline) over the baseline value.

Results

As compared with patients with a higher FMD, those with FMD below the median value (4.3%) were more frequently affected by ischemic cardiopathy (50 vs. 23%; p?=?0.032) and diabetes mellitus (20 vs. 3%; p?=?0.044), had a higher NYHA class (2.5?±?0.5 vs. 1.9?±?0.7; p?<?0.001) and NT-proBNP (2,690?±?3,690 vs. 822?±?1,060; p?=?0.001), lower glomerular filtration rate estimated by Cockcroft-Gault (GFRCG: 63?±?28 vs. 78?±?25; p?=?0.001) and LVEF (29?±?8 vs. 37?±?9; p?=?0.001), as well as more frequently showing a restrictive pattern (40 vs. 7%; p?=?0.002). In a multivariate regression model (R ²?=?0.48; p?<?0.001), FMD remained associated only with the NYHA class (p?=?0.039) and diabetes mellitus (p?=?0.024).

Conclusions

This study demonstrates that a better functional status and absence of diabetes mellitus are associated to higher FMD regardless of the etiology of the cardiac disease.     

Do Fitflops™ increase lower limb muscle activity?

Background

Fitness toning shoes are becoming increasingly popular, they aim to increase muscle activity, raise energy expenditure and improve overall health while wearing them. Yet there is a lack of consensus in the literature regarding their effectiveness. One such shoe on the market is the Fitflop™ designed to activate leg muscles through density shifts in the shoe's sole. The purpose of this study was to investigate the effect of wearing Fitflops^TM on the muscle activity of the lower limb.

Methods

Twenty three females (age 20.8 (1.3)years, mass 62.9 (11.9)kg, height 165.4 (5.6)cm) participated in the study. Muscle activity of the medial gastrocnemius, biceps femoris, rectus femoris and gluteus maximus of the participants' right limb were recorded using surface electromyography during participation in three different tasks to simulate daily living activities. These were a) treadmill walking b) stair climbing and c) zigzag walking around cones. The participants completed the tasks barefoot, while wearing Fitflops™ and while wearing regular flip flops so that comparisons between muscle activity in the different shoe conditions could be made.

Findings

The results show that there was no significant difference in the activity of the medial gastrocnemius, biceps femoris, rectus femoris and gluteus maximus muscles across all shoe conditions and simulated daily activities (P > 0.05).

Interpretation

Based on these results, the use of Fitflops™ is not recommended as a means of increasing muscle activity of the medial gastrocnemius, biceps femoris, rectus femoris and gluteus maximus during activities of daily living in a healthy recreationally active female population.     

Relationship between weakness and phase angle in advanced cancer patients with fatigue

Objective

This study aims to determine the relationship between weakness and bioimpedance analysis (BIA)-derived phase angle in a population of untreated cancer patients with fatigue.

Methods

We prospectively evaluated 41 treatment-naive cancer patients of several origins that presented with performance status 1–2, weight loss >5 % in the last 6 months, and Fatigue Numeral Scale score >4. Weakness was considered a physical component of the multidimensional fatigue syndrome and was evaluated through several parameters utilizing hand grip strength technique by dinamometry. The same assessment was also performed on a healthy control population (n?=?20). BIA-derived phase angle was also determined by BIA.

Results

Compared to healthy controls, cancer patients exhibited significant differences in all the parameters: median fatigue was 6 (range 5–9), evaluated maximal strength mean was 27?±?10.71 vs. 42?±?10.74 kg (p?<?0.0001 for patients vs. control, respectively), and muscle strength difference (max–min muscle strength) was also statistically different (p?<?0.0001). We also determined parameter associations within the patient population. We found statistical significant correlations between median phase angle score and endurance muscle with percentage of weight loss (r?=?0.43, p?=?0.03) for head and neck cancer patients, and in non-small cell lung cancer patients, grip work correlated significantly with normal or decreased phase angle (r?=?0.85), p?=?0.006 (Spearman Rank Correlation).

Conclusions

Weakness could be correlated with normal or decreased phase angle in a population with ambulatory advanced cancer with fatigue naive of treatment. We also found a significant relationship between median phase angle score and endurance muscle with percentage of weight loss in the subpopulation of patients with head and neck carcinoma.     

Comparison of Standardized Uptake Values in Normal Structures Between PET/CT and PET/MRI in an Oncology Patient Population

Purpose

The purpose of this study was to compare and correlate standardized uptake values (SUV) derived from magnetic resonance attenuation correction (MRAC) with those derived from computed tomography attenuation correction (CTAC) in an oncology patient population.

Procedures

The HIPAA-compliant study was approved by the Internal Review Board and all subjects gave written informed consent prior to inclusion in the study. Forty patients (mean age 61?±?15.1; 20 male) referred for clinically indicated 2-deoxy-2-[¹⁸F]fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) scans also underwent a PET/magnetic resonance imaging (MRI) examination. MRAC was performed using an automatic three-segment model. Regions of interest were drawn over eight normal structures in order to obtain SUVmax and SUVmean values. Spearman rank correlation coefficients (r) were calculated and two-tailed paired t tests were performed to compare the SUVmax and SUVmean values obtained from CTAC with those from MRAC.

Results

The mean time after FDG injection was 66?±?7 min for PET/CT and 117?±?15 min for PET/MRI examination. MRAC SUV values were significantly lower than the CTAC SUV values in mediastinal blood pool (p?<?0.001 for both SUVmax and SUVmean) and liver (p?=?0.01 for SUVmean). The MRAC SUV values were significantly higher in bone marrow (p?<?0.001 for both SUVmax and SUVmean), psoas major muscle (p?<?0.001 for SUVmax), and left ventricular myocardium (p?<?0.001 for SUVmax and p?=?0.01 for SUVmean). For the other normal structures, no significant difference was observed. When comparing SUV values generated from CTAC versus MRAC, high correlations between CTAC and MRAC were observed in myocardium (r?=?0.96/0.97 for SUVmax/mean), liver (r?=?0.68 for SUVmax), bone marrow (r?=?0.80/0.83 for SUVmax/mean), lung tissue (r?=?0.70 for SUVmax), and mediastinal blood pool (r?=?0.0.68/.069 for SUVmax/mean). Moderate correlations were found in lung tissue (r?=?0.67 for SUV mean), liver (r?=?0.66 for SUVmean), fat (r?=?0.48/0.53 for SUVmax/mean), psoas major muscle (r?=?0.54/0.58 for SUVmax/mean), and iliacus muscle (r?=?0.41 for SUVmax). Low correlation was found in iliacus muscle (r?=?0.32 for SUVmean).

Conclusions

Using the automatic three-segment model, our study showed high correlation for measurement of SUV values obtained from MRAC compared to those from CTAC, as the reference standard. Differences observed between MRAC and CTAC derived SUV values may be attributed to the time-delay between the PET/CT and PET/MRI scans or biologic clearance of radiotracer. Further studies are required to assess SUV measurements when performing different MR attenuation correction techniques.     

Changes of QTc interval after opioid switching to oral methadone

A consecutive sample of patients who were switched from strong opioids to methadone in a period of 1 year was surveyed. QTc was assessed before switching (T0) and after achieving adequate analgesia and an acceptable level of adverse effects (Ts). Twenty-eight of 33 patients were switched to methadone successfully. The mean initial methadone doses at T0 were 67.1 mg/day (SD ±80.2, range 12–390). The mean QTc interval at T0 was 400 ms (SD ±30, range 330–450). The mean QTc interval at Ts (median 5 days) was 430 ms (SD ±26, range 390–500). The difference (7.7 %) was significant (p?<?0.0005). Only two patients had a QTc of 500 ms. No serious arrhythmia was observed. At the linear regression analysis, there was no significant association between mean opioid doses expressed as oral morphine equivalents and QTc at T0 (p?=?0.428), nor between mean methadone doses and QTc at Ts (p?=?0.315). No age differences were found with previous opioid doses (p?=?0.917), methadone doses (p?=?0.613), QTc at T0 (p?=?0.173), QTc at Ts (p?=?0.297), and final opioid–methadone conversion ratio (p?=?0.064). While methadone used for opioids switching seems to be an optimal choice to improve the opioid response in patients poorly responsive to the previous opioid, the possible QTc prolongation should be of concern despite not producing clinical consequences in this group of patients. A larger number of patients should be assessed to quantify the risk of serious arrhythmia.     

Muscle Ultrasound Changes Correlate With Functional Impairment in Spinal Muscular Atrophy

ObjectiveWe investigated ultrasound patterns of muscle involvement in different types of spinal muscular atrophy (SMA) and their correlation with functional status to determine the pattern of muscle compromise in patients with SMA and the potential role of ultrasound to evaluate disease progression.MethodsWe examined muscles (biceps brachii, rectus femoris, diaphragm, intercostals and thoracic multifidus) of 41 patients with SMA (types 1 to 4) and 46 healthy age- and sex-matched control individuals using B-mode ultrasound for gray-scale analysis (GSA), area (biceps brachii and rectus femoris) and diaphragm thickening ratio. Functional scales were applied to patients only. We analyzed ultrasound abnormalities in specific clinical subtypes and correlated findings with functional status.ResultsCompared with controls, patients had reduced muscle area and increased mean GSA for all muscles (p < 0.001), with an established correlation between the increase in GSA and the severity of SMA for biceps brachii, rectus femoris and intercostals (p = 0.03, 0.01 and 0.004 respectively) when using the Hammersmith Functional Motor Scale Expanded. Diaphragm thickening ratio was normal in the majority of patients, and intercostal muscles had higher GSA than diaphragm in relation to the controls.ConclusionUltrasound is useful for quantifying muscular changes in SMA and correlates with functional status. Diaphragm thickening ratio can be normal even with severe compromise of respiratory muscles in quantitative analysis, and intercostal muscles were more affected than diaphragm.     

Adverse effects of permanent atrial fibrillation on heart failure in patients with preserved left ventricular function and chronic right apical pacing for complete heart block

Background

The impact of atrial fibrillation (AF) on heart failure (HF) was evaluated in patients with preserved left ventricular (LV) function and long-term right ventricular (RV) pacing for complete heart block.

Methods

Clinical, echocardiographic, and laboratory parameters of HF were assessed in 35 patients with established AF who had undergone ablation of the atrioventricular node and pacemaker implantation (Group A) and 31 patients who received dual-chamber pacing for spontaneous complete heart block (Group B).

Results

During a follow-up period of 12.7?±?7.5?years, New York Heart Association (NYHA) functional class increased from 1.3?±?0.5 to 2.1?±?0.6 (p?p?p?p?=?0,21) in Group B. At the end of follow-up, markers of LV function were moderately depressed in Group A compared with those in Group B: NYHA class 2.1?±?0.6 versus 1.6?±?0.7, p?=?0.001; LVEF 53.0?±?8.2 versus 56.9?±?7.0?%, p?p?p?10?%, increasing NYHA class ≥1, and NT-proBNP levels >1,000?pg/ml.

Conclusions

Permanent AF was associated with adverse effects on LV function and symptoms of HF in patients with long-term RV pacing for complete heart block, and appears to play an important role in the development of HF in this specific patient cohort.     

Leg Muscle Activation and Distance Setting of the Leg Cycle Ergometer for Use by the Elderly

[Purpose] This study verified the leg muscle activities of elderly subjects performing leg cycle ergometer exercise. [Subjects] Forty-one elderly persons were the subjects of this study. [Methods] For the three distances corresponding to knee flexion angles of 15, 45, and 70, the muscle activities of the rectus femoris, biceps femoris, tibialis anterior and lateral gastrocnemius were measured while the subjects exercised on a cycle ergometer. [Results] The rectus femoris and biceps femoris showed statistically significant increases as the distance between the cycle ergometer and the body increased, and the lateral gastrocnemius muscle activation showed a statistically significant increase as the distance from the body to the cycle ergometer decreased. [Conclusion] When the elderly have limb muscle weakness, leg cycle ergometer distances should be adjusted.Key words: Cycle ergometer, Electromyography, Selective muscle strengthening     

Impact of decline-board squat exercises and knee joint angles on the muscle activity of the lower limbs

[Purpose] This study aims to investigate how squat exercises on a decline board and how the knee joint angles affect the muscle activity of the lower limbs. [Subjects] The subjects were 26 normal adults. [Methods] A Tumble Forms wedge device was used as the decline board, and the knee joint angles were measured with a goniometer. To examine the muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior of the lower limbs, a comparison analysis with electromyography was conducted. [Results] The muscle activity of the biceps femoris, rectus femoris, gastrocnemius lateralis, and tibialis anterior increased with increased knee joint angles, both for squat exercises on the decline board and on a flat floor. When the knee joint angle was 45°, 60°, and 90°, the muscle activity of the rectus femoris was significantly higher and that of the tibialis anterior was significantly lower during squat exercises on the decline board than on the flat floor. When the knee joint angle was 90°, the muscle activity of the gastrocnemius lateralis was significantly lower. [Conclusion] Squat exercises on a decline board are an effective intervention to increase the muscle activity of the rectus femoris with increased knee joint angles.Key words: Decline board, Squat exercise, Range of motion     

Ultrasound Measurements of Skeletal Muscle Architecture Are Associated with Strength and Functional Capacity in Older Adults

The goal of this study was to determine whether ultrasound measures of muscle architecture can be used to infer strength and functional capacity in older adults. Thirty-six healthy older adults (aged 68.2 ± 5.3 y) undertook isokinetic dynamometry for isometric and isokinetic concentric knee extensor strength, the 6-m fast walk, timed up and go, stair climb and descent and vertical jump tests. Longitudinal brightness-mode ultrasound scans (probe frequency, 10 MHz) of the vastus lateralis, vastus intermedius, rectus femoris and gastrocnemius medialis were obtained, and muscle architecture measures (thickness, fascicle pennation angle and fascicle length) were correlated with the aforementioned strength and functional measures. Quadriceps thickness was a significant (p < 0.05) independent predictor of isometric and isokinetic knee extensor strength (R² ≥ 0.630). Gastrocnemius medialis thickness was a significant independent predictor of 6-m fast walk test (R² = 0.216, p < 0.05), timed up and go test (R² = 0.455, p < 0.01), stair climb power (R² = 0.591, p < 0.01), stair descent power (R² = 0.608, p < 0.01) and vertical jump height (R² = 0.579, p < 0.01). Ultrasound is a safe, non-invasive and efficient tool for inferring the strength and functional capacity of older adults.     

Evaluating the relationship between quadriceps muscle quality captured using ultrasound with clinical severity in women with knee osteoarthritis

BackgroundInfiltration of muscle with non-lean tissue, such as fat, reduces muscle quality. Ultrasound captures muscle quality through measurement of echogenicity. Given the potential implications of quadriceps muscle quality on physical function, particularly in knee osteoarthritis, the purpose of this study was to investigate the relationship between echogenicity, muscle thickness and subcutaneous fat thickness with the clinical severity of osteoarthritis.MethodsThirty-one women with clinical knee osteoarthritis participated. Rectus femoris and vastus lateralis echogenicity, muscle thickness and subcutaneous fat thickness were measured from ultrasound images of the most symptomatic knee. Clinical severity of osteoarthritis was characterized with pain, self-reported function, six-minute walk test, and knee extensor strength. Correlation coefficients were calculated between muscle and fat architecture outcomes (muscle quality, muscle and fat thicknesses) and osteoarthritis clinical severity outcomes.FindingsData from 25 women were of sufficient quality for analysis. Echogenicity (muscle quality) related to the six-minute walk test for both rectus femoris (r = −0.52, p = 0.02) and vastus lateralis (r = −0.74, p = 0.004), with poorer muscle quality related to lower mobility. Subcutaneous fat thickness was related to the six-minute walk test (rectus femoris, r = −0.61, p = 0.0012; vastus lateralis, r = −0.73, p = 0.003) and strength (rectus femoris, r = −0.46, p = 0.02; vastus lateralis, r = −0.59, p = 0.03). Muscle thickness was not related to any severity outcomes.InterpretationMuscle quality, rather than thickness, is associated with mobility performance in women with knee osteoarthritis. Thus, interventions for osteoarthritis that specifically target muscle quality, rather than size, should be explored.