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International audience; Purpose: No therapeutic consensus has been established about proximal ruptures of the rectus femoris muscle. The objective of this literature review is to determine a therapeutic course of action. Methods: We conducted a literature review on the PubMed database using the following keywords (in French and English, respectively): "quadriceps/quadriceps", "droit ant erieur/rectus femoris", "proximal/ proximal", "chirurgie/surgical", "avulsion/avulsion". We collected 266 articles, 36 of them were selected, which were related to our topic: proximal rupture of the anterior rectus femoris. Patients with a proximal rupture of the rectus femoris, minor or major patient of traumatic origin were included in this study. Patients injured at another lesion level, or non-traumatic lesions of the proximal rectus femoris (tendinitis without ruptures, tumor or others) were excluded. For each patient, the indications, the type of treatment and the functional result were analyzed, with the time to recovery and the level of recovery from sports and professional activities (same sport/profession or not, same level or not) as the main criterion of judgment. Fisher exact test was used for statistical comparison. Results: The aims of conservative treatment are to be pain free for the patient, to fight hematoma and to rehabilitate the injury as quickly as possible. The surgical techniques are varied, with most consisting of either a reinsertion of the musculo-tendon stump or a resection of the scar tissue with myo-tendinoaponeurotic suture in place. The functional results are good for the majority of the treatments proposed, but the conservative treatment has a shorter recovery time (3 months vs. 4 months for the best surgical results). Highly displaced bone avulsion is the only indication for first-line surgical treatment. Conclusion: The main disadvantage of conservative treatment is the risk of residual pain beyond 3 months (10%), justifying an MRI to guide secondary surgical treatment. We propose a treatment plan for proximal rupture of the proximal rectus femoris rupture.

Objective To describe the injury mechanism and its association with magnetic resonance imaging (MRI) injury findings in acute rectus femoris injuries. Design Combined retrospective and prospective descriptive injury study. Retrospective cohort from January 2010 to October 2013 and prospective cohort from October 2013 to January 2019. Setting Specialized sports medicine hospital. Participants Male professional football players older than 18 years playing in a national football league, referred for injury assessment within 7 days after an acute rectus femoris injury, with a positive finding on MRI. Independent variables Rectus femoris muscle injury MRI findings in relation to injury mechanism in male football players. Main outcome measures Rectus femoris injury mechanism (kicking, sprinting, and others), MRI injury location, and grade. Results There were 105 injuries in total, with 60 (57.1%) and 45 (42.8%) injuries from the retrospective and prospective cohorts, respectively. Kicking was the injury mechanism in 57 (54.3%) of all acute rectus femoris injuries, sprinting represented 32 (30.4%), and 16 (15.2%) were classified as others. There were 20 (19.05%) free tendon, 67 (63.8%) myotendinous junction and/or intramuscular tendon, and 18 (17.1%) peripheral myofascial located injuries. All free tendon injuries were related to kicking and graded as a complete tear of at least one of the tendons in 15/20 (75.0%) cases. Conclusions Kicking seems to be an important mechanism related to complete ruptures and injuries occurring at the proximal free tendon. Sprinting was the other most common mechanism but was never associated with injury to the proximal free tendon.

Background & aims: Muscle mass is an important biomarker of survival from a critical illness; however, there is no widely accepted method for routine assessment of low muscularity at intensive care unit (ICU) admission. We hypothesize that ultrasound-based partial muscle mass assessments can reflect the trunk muscle mass. Therefore, we aimed to investigate whether ultrasound muscle mass measurements could reflect trunk muscle mass and identify patients with low muscularity. Methods: We performed a retrospective analysis of prospectively obtained ultrasound data at ICU admission. We included patients who underwent computed tomography (CT) imaging at the third lumbar vertebra (L3) within 2 days before and 2 days after ICU admission. Primary outcomes included the correlation between the femoral muscle mass measurements using ultrasound and the cross-sectional area (CSA) at L3 obtained by CT. Low muscularity was defined as a skeletal muscle index of 36.0 cm2/m2 for males and 29.0 cm2/m2 for females. Secondary outcomes included the correlation with the ultrasound measurements of the biceps brachii muscle mass and diaphragm thickness. Results: Among 133 patients, 89 underwent CT imaging, which included the L3. The patient mean age was 72 ± 13 years, and 60 patients (67%) were male. The correlation between the femoral muscle ultrasound and CT was ρ = 0.57 (p < 0.01, n = 89) and ρ = 0.48 (p < 0.01, n = 89) for quadriceps muscle layer thickness and rectus femoris muscle CSA, and these had the discriminative power to assess low muscularity, with the areas under the curve of 0.84 and 0.76, respectively. The ultrasound measurements of the biceps brachii muscle mass and diaphragm thickness were correlated with CT imaging [ρ = 0.57–0.60 (p < 0.01, n = 52) and ρ = 0.35 (p < 0.01, n = 79)]. Conclusions: Ultrasound measurements of muscle mass were correlated with CT measurements, and the measurements of femoral muscle mass were useful to assess low muscularity at ICU admission.

This study was planned to determine the muscle architecture (pennation angle, muscle fiber length, and muscle thickness) and its relationship to lower extremity muscle strength in patients with Multiple Sclerosis (pwMS). The muscle architecture (pennation angle, muscle fiber length, and muscle thickness) and lower extremity muscle strength were assessed in 33 pwMS [13 Relapsing–Remitting MS (RRMS), 5 Primary Progressive MS (PPMS), 5 Secondary Progressive MS (SPMS), and 11 matched healthy controls (HC)]. Muscle architecture features were assessed with ultrasonography and muscle strength were assessed with a digital hand-held dynamometer. The rectus femoris muscle thickness and pennation angle, gastrocnemius muscle thickness, and the tibialis anterior pennation angle were significantly lower in pwMS compared to HC (p

This study aimed to examine the effects of age on hip flexion maximal and rapid strength and rectus femoris (RF) muscle size and composition in men. Fifteen young (25 [3] y) and 15 older (73 [4] y) men performed isometric hip flexion contractions to examine peak torque and absolute and normalized rate of torque development (RTD) at time intervals of 0 to 100 and 100 to 200 milliseconds. Ultrasonography was used to examine RF muscle cross-sectional area and echo intensity. Peak torque, absolute RTD at 0 to 100 milliseconds, and absolute and normalized RTD at 100 to 200 milliseconds were significantly lower (P = .004–.045) in the old compared with the young men. The older men exhibited lower cross-sectional area (P = .015) and higher echo intensity (P = .007) than the young men. Moreover, there were positive relationships between cross-sectional area and absolute RTD at 0 to 100 milliseconds (r = .400) and absolute RTD at 100 to 200 milliseconds (r = .450) and negative relationships between echo intensity and absolute RTD at 100 to 200 milliseconds (r = −.457) and normalized RTD at 100 to 200 milliseconds (r = −.373). These findings indicate that hip flexion maximal and rapid strength and RF muscle size and composition decrease in old age. The relationships observed between ultrasound-derived RF parameters and measurements of RTD suggest that these age-related declines in muscle size and composition may be relevant to hip flexion rapid torque production.

Background: Little is known about how chronic unilateral anterior knee pain (AKP) affects bilateral quadriceps function and lower quarter flexibility. Objective: To determine if patients with chronic unilateral AKP present bilateral deficits in quadriceps function and lower quarter flexibility. Methods: Twenty-two patients with chronic unilateral AKP (pain duration: 48.6 months) and 22 matched healthy controls were evaluated. Pain perception and functional outcomes were obtained. Knee joint and thigh circumferences, quadriceps subcutaneous tissue thickness and function (i.e. maximal and explosive strength, activation, and endurance), and lower quarter flexibility (i.e. hamstrings and iliopsoas/rectus femoris muscle) in both legs were compared across conditions. Results: Knee joint and thigh circumferences, and quadriceps subcutaneous tissue thickness were not different between conditions (P ≥ .39). Compared with matched healthy controls, patients with chronic unilateral AKP showed: 1) greater pain perception (0.0 versus 4.4 cm, P < .0001); 2) a lower score for functional outcomes (79.6 versus 53.9, P < .0001); 3) less bilateral quadriceps maximal (3.5 versus 2.8 Nm/kg, P < .0001) and explosive (10.8 versus 8.7 Nm/kg/s, P = .01) strength, activation (0.95 versus 0.83, P < .0001), and endurance (1.66 versus 1.52 Nm/kg, P = .02); and 4) less bilateral hamstrings (86.8 versus 72.6°, P = .002) and iliopsoas/rectus femoris (11.6 versus 7.8°, P < .05) flexibility. Conclusion: Patients with chronic unilateral AKP (without knee joint effusion or quadriceps muscle atrophy) appear to have bilateral deficits in quadriceps function and lower quarter flexibility, which should be addressed with pain reduction.

Background The aim of this study was to analyze the long-term outcomes of extensor tendon ruptures of the knee using exact measuring tools. Methods The results of patients treated for extensor tendon rupture with a minimum follow up of 10 years were reviewed. Electromyography (EMG) and three-dimensional (3D) gait analyses were performed and compared with the healthy side of each patient and with the gait patterns of 20 healthy controls. Functional outcome scores were assessed using the Lysholm score and Knee Injury and Osteoarthritis Outcome Score (KOOS). Results After a mean of 13.4 ± 3 years, 23 patients were available for follow up. The mean Lysholm score was 86.6, and the KOOS averaged 78.1. Gait analysis showed no major kinematic differences between these patients compared with healthy controls. In the squat test, the mean peak amplitude of the rectus femoris muscle was significantly smaller on the injured side than on the healthy side (140.21 ± 66.13 μV vs. 168.25 ± 91.77 μV; P = 0.01). The mean peaks of the vastus lateralis and medialis EMG signals were also lower on the injured side (P = 0.63; P = 0.08). Correspondingly, the thigh girth at 20 cm and 10 cm above the knee was significantly lower on the injured side. One patient had re-rupture after patella tendon repair. Conclusion At long-term follow up the patients reached good clinical outcomes and exhibited mainly physiological gait patterns after rupture of knee extensor tendons. However, the thigh muscles showed hypotrophy and a significantly smaller EMG signal amplitude during a high-intensity task on the formerly injured side.

Ferris, JR, Tomlinson, MA, Ward, TN, Pepin, ME, and Malek, MH. Reduced electromyographic fatigue threshold after performing a cognitive fatiguing task. J Strength Cond Res 35(1): 267-274, 2021-Cognitive fatigue tasks performed before exercise may reduce exercise capacity. The electromyographic fatigue threshold (EMGFT) is the highest exercise intensity that can be maintained without significant increase in the electromyography (EMG) amplitude vs. time relationship. To date, no studies have examined the effect of cognitive fatigue on the estimation of the EMGFT. The purpose of this study, therefore, was to determine whether cognitive fatigue before performing exercise reduces the estimated EMGFT. Eight healthy college-aged men were recruited from a university student population and visited the laboratory on multiple occasions. In a randomized order, subjects performed either the cognitive fatigue task (AX continuous performance test) for 60 minutes on one visit (experimental condition) or watched a video on trains for 60 minutes on the other visit (control condition). After each condition, subjects performed the incremental single-leg knee-extensor ergometry test while the EMG amplitude was recorded from the rectus femoris muscle and heart rate was monitored throughout. Thereafter, the EMGFT was calculated for each subject for each visit and compared using paired samples t-test. For exercise outcomes, there were no significant mean differences for maximal power output between the 2 conditions (control: 51 ± 5 vs. fatigue: 50 ± 3 W), but there was a significant decrease in EMGFT between the 2 conditions (control: 31 ± 3 vs. fatigue: 24 ± 2 W; p = 0.013). Moreover, maximal heart rate was significantly different between the 2 conditions (control: 151 ± 5 vs. fatigue: 132 ± 6; p = 0.027). These results suggest that performing the cognitive fatiguing task reduces the EMGFT with a corresponding reduction in maximal heart rate response.

de Camargo, JBB, Braz, TV, Batista, DR, Germano, MD, Brigatto, FA, and Lopes, CR. Dissociated time course of indirect markers of muscle damage recovery between single-joint and multi-joint exercises in resistance-trained men. J Strength Cond Res XX(X): 000-000, 2020-This study compared the time course of indirect markers of muscle damage after multi-joint and single-joint exercises. Ten resistance-trained men (years: 26.9 ± 3.0; total body mass: 83.2 ± 13.8 kg; height: 176 ± 7.0 cm; resistance training [RT] experience: 5.5 ± 2.4 years; RT frequency: 5.3 ± 0.7 sessions; relative squat 1 repetition maximum: 1.4 ± 0.3) performed, in a random order, 5 sets of 8 repetition maximum of the back squat (BS) and knee extension (KE) exercises. Rectus femoris muscle thickness (MTRF), leg circumference (LC), and muscle soreness (MS) were recorded at baseline (pre), 0, 12, 24, and 36 hours after each exercise protocol. There was a significant increase (p < 0.05) in dependent variables at every time point after both the multi-joint and single-joint exercise sessions. However, MTRF and LC were greater at 0 and 36 hours, and MS was greater at 24 and 36 hours after BS when compared with KE (all p < 0.05). This study shows that resistance-trained individuals can experience significant higher levels of indirect markers of muscle damage when performing a multi-joint lower-limb exercise compared with a single one.

Objectives The relation between increase of tonus and joint movement velocity is controversial in Parkinson's rigidity. It is accepted that the increase of tonus in rigidity is constant during joint movement, and does not change within all limits of movement. However, there is thoughtful evidence that the change in tonus in rigidity has a correlation with joint movement velocity and amplitude of movement. The pendulum movement that is formed by triggering of the patellar T reflex allows the examination of phasic stretching reflexes and physiological changes of passive stretching. Therefore, the velocity and amplitude properties of tonus in Parkinson's rigidity can be scanned together. Materials and methods Patellar T reflex-triggered patellar pendulum was recorded in 40 Parkinson's patients. The velocity and amplitude changes in the pendulum were observed according to the rigidity scale. Muscle action potentials were recorded from the rectus femoris muscle and biceps femoris muscles simultaneously via superficial recording electrodes. Knee joint angle changes were recorded with a goniometer. The kinesiological and electromyographic features were compared with those of the control subjects. Results The number of pendulums decreased significantly, the angle of joint movement decreased, the peak time decreased and the angular velocity slowed down significantly in the Parkinson's group. While the latency of the patellar T reflex did not change significantly, its amplitude decreased, and the onset time of joint movement measured by accelerometer was prolonged. Conclusions Parkinson's rigidity has a velocity-dependent component, and this correlates negatively with the rigidity scale.

The purpose of this study was to determine if muscular dimensional changes with increases in torque production are influenced by age- and obesity-related increases in intramuscular fat, and its relationship to percent body fat (%BF), echo intensity (EI), strength, and maximum walking speed. Sixty-six healthy men were categorized into 3 groups based on age and body mass index status (young normal weight [YNW], older normal weight [ONW], and older obese [OB]). Participants underwent %BF assessments, resting ultrasonography to determine muscle size (cross-sectional area [CSA]) and EI of the superficial quadriceps, and a 10-m maximum walking speed assessment. Maximal and submaximal (rest–100% MVC in 10% increments) isometric leg extension strength was assessed while changes in rectus femoris (RF) CSA, width, and depth were obtained with ultrasonography. Echo intensity and %BF were different among all groups (p ≤ .007), with the YNW and OB groups exhibiting the lowest and highest %BF and EI values, respectively. The RF increased in depth and decreased in width with increases in torque intensity for all groups. The ONW group demonstrated no change (−0.08%) in RF CSA across torque intensities, whereas the YNW group (−11.5%) showed the greatest decrease in CSA, and the OB group showed a more subtle decrease (−4.6%). Among older men, a greater change in RF CSA was related to poorer EI (r = −0.355) and higher %BF (r = −0.346), while a greater decrease in RF width was associated with faster walking speeds (r = −0.431). Examining muscular dimensional changes during contraction is a unique model to investigate the influence of muscle composition on functional performance.

Electrical muscle stimulation is widely used to enhance lower limb mobilization. Although upper limb muscle atrophy is common in critically ill patients, electrical muscle stimulation application for the upper limbs has been rarely reported. The purpose of this study was to investigate whether electrical muscle stimulation prevents upper and lower limb muscle atrophy and improves physical function.Randomized controlled trial.Two-center, mixed medical/surgical ICU.Adult patients who were expected to be mechanically ventilated for greater than 48 hours and stay in the ICU for greater than 5 days.Forty-two patients were randomly assigned to the electrical muscle stimulation (n = 17) or control group (n = 19).Primary outcomes were change in muscle thickness and cross-sectional area of the biceps brachii and rectus femoris from day 1 to 5. Secondary outcomes included occurrence of ICU-acquired weakness, ICU mobility scale, length of hospitalization, and amino acid levels. The change in biceps brachii muscle thickness was -1.9% versus -11.2% in the electrical muscle stimulation and control (p = 0.007) groups, and the change in cross-sectional area was -2.7% versus -10.0% (p = 0.03). The change in rectus femoris muscle thickness was -0.9% versus -14.7% (p = 0.003) and cross-sectional area was -1.7% versus -10.4% (p = 0.04). No significant difference was found in ICU-acquired weakness (13% vs 40%; p = 0.20) and ICU mobility scale (3 vs 2; p = 0.42) between the groups. The length of hospitalization was shorter in the electrical muscle stimulation group (23 d [19-34 d] vs 40 d [26-64 d]) (p = 0.04). On day 3, the change in the branched-chain amino acid level was lower in the electrical muscle stimulation group (40.5% vs 71.5%; p = 0.04).In critically ill patients, electrical muscle stimulation prevented upper and lower limb muscle atrophy and attenuated proteolysis and decreased the length of hospitalization.

Purpose: Skeletal muscle mass (SMM) depletion and sarcopenia as predictors of postoperative complications and poorer overall survival (OS) have been validated in many surgical fields through cross-sectional imaging (CT, MRI), with potential limitations. We evaluated it in a stage III–IV head and neck squamous cell carcinoma (HNSCC) surgical cohort through ultrasound (US) of rectus femoris muscle (RF), a quick, cheap, repeatable alternative. Methods: Patients submitted to surgical treatment with curative purpose were recruited and prospectively evaluated through clinical, biometric, biochemical, surgical, pathological and functional prognosticators and with preoperative US of RF with regards to 30-day complications and OS. Results: Forty-seven patients completed the study. RF cross-sectional area (RF-CSA) was used to identify patients with low SMM (CSA ≤ 0.97cm2: 18/47, 38.3%). RF-CSA was lower in complicated cases (0.95 ± 0.48 vs 1.41 ± 0.49cm2; p = 0.003), remaining the only independent predictor of postoperative complications at multivariate analysis, with a model including ASA score and modified Frailty index (OR 9.84; p = 0.004). SMM depletion significantly impaired OS (13.6 ± 2.9 vs 26.3 ± 2.1months; p = 0.017), being its only independent prognosticator at multivariate Cox regression analysis (OR 4.42; p = 0.033). Conclusion: RF-CSA, evaluated with US, seems a reliable method for identification of patients with low SMM in a stage III–IV HNSCC cohort, defining a subset at high-risk of 30-day complications and poorer OS.

Objective In Para-cycling competitions, cyclists with amputation of one-leg and no prosthesis, i.e., Division Cycle, Sport Class C2, perform pedaling movement on bicycle by unilateral leg. The purpose of this study was to describe neuromuscular activation of lower extremity muscles in two cyclists with single leg amputation and one cyclist with two legs during pedaling. We compared averaged rectified values (ARV) of surface electromyography for lower extremity muscles during crank cycle for two single leg cyclists with one cyclist with two legs at 65%, 80%, and 95% of VO2 max. Results Characteristic features of cyclists with single amputation of leg were increases in ARV for proximal region of the rectus femoris muscle in first half of pulling phase, increases in ARV for the biceps femoris muscle in first half of pulling phase, and increases in ARV for the medial gastrocnemius muscle in pulling phase. These findings in this study suggest that cyclists with single amputation of leg use characteristic neuromuscular coordination in the muscles contributing to hip and knee flexion joint moments during pulling phase and this may be the strategy in cyclists with single amputation of leg to compensate lack of hip and/or knee extension torque from contralateral leg.

Analysis of muscle composition using ultrasound requires standardization of several equipment settings (i.e. gain). However, the influence of image resolution, which is altered by imaging depth, on measures of muscle composition is unknown.We analysed rectus femoris muscle composition using ultrasound images captured from 32 males and females (aged 28 ± 5 years) at depths of 9.0, 7.3, 5.9 and 4.7 cm. The transducer's orientation was fixed using a clamp during image acquisition to minimize movement. Across each image resolution, a region of interest encompassing the same anatomical area within the muscle was used for muscle composition analysis. Muscle composition was analysed using a combination of first-, second- and higher-order texture features. Muscle composition agreement across image resolutions was evaluated using a one-way ANOVA and intraclass correlation coefficients (ICC).Most muscle composition features displayed differences due to image resolution (p .05). ICCs demonstrated poor-to-good agreement across different image resolutions. In general, higher resolution images (i.e. shallower imaging depth) demonstrated better agreement (ICC 0.90) compared to lower resolution images.Ultrasound image resolution influences muscle composition analysis. Image resolution should be fixed within and between individuals when evaluating muscle composition using ultrasound.

Objective Groin wound complications after femoral artery reconstructions are highly morbid and notoriously difficult to treat. Successful techniques include long-term antibiotic therapy, operative debridement, and muscle flap coverage. Historically, more complex muscle flap coverage, such as a rectus femoris muscle flap (RFF), has been performed by plastic and reconstructive surgeons. In this study, the experience of vascular surgeons performing RFF in the management of wound complications after femoral artery reconstructions is reported. Methods Clinical data between 2012 and 2018 were retrospectively analyzed. Data were summarized, and standard statistical analysis was performed. Results There were 23 patients who underwent 24 RFFs for coverage of complex groin wounds after femoral artery reconstructions. One of the 23 patients underwent bilateral RFFs. In this study cohort, patients had a median age of 67.5 years, and 79% (n = 19) were male. Median body mass index was 28.0 kg/m2, and 38% of patients were classified as obese on the basis of body mass index criteria. A history of tobacco use was present in 88%; however, only 29% were current smokers. Diabetes was present in 38% of patients and chronic kidney disease in 29%. Of the 24 RFFs, 14 (58%) were constructed in patients with reoperative groin surgery resulting in the need for muscle flap coverage. Femoral endarterectomy was the most common index procedure (46%), followed by infrainguinal leg bypass surgery (17%) and aortobifemoral bypass (17%). Grafts used during the original reconstruction included 12 bovine pericardial patches (50%), 6 Dacron grafts (25%), 4 PTFE grafts (17%), and 2 autogenous reconstructions (8%). Microbiology data identified 33% of patients (n = 8) to have gram-positive bacterial infections alone, 21% (n = 5) to have gram-negative infections alone, and 29% (n = 7) to have polymicrobial infections; 4 patients (13%) had negative intraoperative culture data. Median hospital stay after RFF was 8 days, and median follow-up time was 29.3 months. Major amputation was avoided in 20 of 24 limbs (83%) undergoing RFF. Eight patients underwent intentional graft or patch explantation (33%) before RFF, whereas 14 of the remaining 15 patients (93%) had successful salvage of the graft or patch after RFF. Two of the patients (13%) who underwent RFF with the intention of salvaging a prosthetic graft or patch required later graft excision. After RFF, 30-day and 1-year survival was 96% and 87%, respectively. Conclusions RFF coverage of complex groin wounds after femoral artery reconstructions may safely be performed by vascular surgeons with excellent outcomes.

Objective There is currently no diagnostic test for PMR. A characteristic pattern of extracapsular inflammation as assessed by contrast-enhanced MRI (ceMRI) has recently been described in the pelvis of patients with PMR. We aimed to evaluate the performance of inflammatory ceMRI signals at predefined pelvic sites as a diagnostic test for PMR. Methods Pelvic MRI scans of patients with pelvic girdle pain (n = 120), including 40 patients with an expert diagnosis of PMR and 80 controls with other reasons for pelvic pain were scored by three blinded radiologists, who evaluated the degree of contrast enhancement at 19 predefined tendinous and capsular pelvic structures. Different patterns of involvement were analysed statistically. Results The frequency of bilateral peritendinitis and pericapsulitis including less common sites, such as the proximal origins of the m. rectus femoris and m. adductor longus, differed significantly between PMR cases and controls: 13.4 ± 2.7 vs 4.0 ± 2.3. A cut-off of ≥10 inflamed sites discriminated well between groups (sensitivity 95.8%, specificity 97.1%). Bilateral inflammation of the insertion of the proximal m. rectus femoris or adductor longus tendons together with ≥3 other bilaterally inflamed sites performed even better (sensitivity 100%, specificity 97.5%). Conclusion This study confirms that a distinctive MRI pattern of pelvic inflammation (bilateral peritendinitis and pericapsulitis and the proximal origins of the m. rectus femoris and m. adductor longus) is characteristic for PMR. The high sensitivity and specificity of the set of anatomical sites evaluated suggests their clinical usefulness as a confirmatory diagnostic test.

Paratonia, a form of hypertonia typically seen in dementia, is often associated with difficulties in positioning and daily care. No evidence-based therapy or clinical guideline for management is available. In this study, the short-term effect of harmonic techniques (HT) and supporting cushions (SC) on paratonia was explored.This was a multicenter interventional clinical trial with AB/BA crossover design. Each intervention (SC or HT) was subsequently implemented over 1 week in each of the participants.The study included 22 participants with moderate to severe paratonia from 9 different nursing homes in Flanders, Belgium.Measurements of biceps brachii and rectus femoris muscle tone (MyotonPRO), maximal elbow and knee extension (goniometer), and pain (Pain Assessment Checklist for Seniors With Limited Ability to Communicate) were performed on 3 different days within 1 week. The effect of HT on nursing care was evaluated with the Pain Assessment Checklist for Seniors With Limited Ability to Communicate and visual analog scale ratings of discomfort items.After 30 minutes of positioning with SC, participants had lower biceps brachii muscle tone (P = .041) and higher maximal elbow extension (P = .006) than without SC. After a 30-minute session of HT, a significant increase in biceps brachii muscle tone (P = .032) and maximal extension of elbow (P .001) and knee (P = .028) was found. Pain (P = .003) and discomfort (P = .001 to P = .019) during morning care were significantly lower when care was preceded by 30 minutes of HT.This explorative study revealed beneficial short-term effects on range of motion for both SC and HT and a positive effect of SC on upper limb muscle tone. Beneficial effects of HT were found on resident's pain and caregiver's discomfort during care. The results of the present study are encouraging and can contribute to the development of evidence-based interventions for paratonia.

BACKGROUND Knee stability has an important role in the gait of hemiplegic stroke patients. However, factors affecting knee stability have not been assessed concerning gait. The purpose of this study was to explore whether co-contraction of the lower limb muscles contributes to the knee stability during the stance phase of the gait cycle in hemiplegic stroke patients. MATERIAL AND METHODS A total of 30 hemiplegic stroke patients, ages 36-79 years, were instructed to walk at their natural speed. The root mean square of surface electromyography was used to measure activities of the biceps femoris and rectus femoris muscles, while the co-contraction ratio was computed based on the root mean squares. The peak angle of knee extension was acquired in the stance phase by 3D kinematic analyses. Lower limb function was evaluated using the Fugl-Meyer scale for lower limb motor assessment. RESULTS A statistically significant increase of the muscle co-contraction ratio of the involved extremity was observed compared with that of the uninvolved extremity (t=-4.066, P

In recent years, whole-body vibration (WBV) training has been used as a training method in health promotion. This study attempted to use WBV at three different frequencies (20, 30, and 40 Hz) with subjects from different age groups to analyze the activation of the rectus femoris muscle. The subjects included 47 females and 51 males with an average age of 45.1 ± 15.2 years. Results indicated significant differences in subjects from different age groups at 20 Hz WBV. Muscle contraction was greater in the subjects who were older (F(4,93) = 82.448, p &lt, 0.001). However, at 30 Hz WBV, the difference was not significant (F(4,93) = 2.373, p = 0.058). At 40 Hz WBV, muscle contraction was less in the older subjects than in the younger subjects (F(4,93) = 18.025, p &lt, 0.001). The spectrum analysis also indicated that at 40 Hz there was less muscle activity during WBV in the older subjects than in the younger ones. Therefore, age was found to have a significant effect on muscle activation during WBV at different frequencies. If the training is offered to elderly subjects, their neuromuscular responses to 20 Hz WBV will be more suitable than to 40 Hz WBV.

Standing yoga poses strengthen a person’s legs and helps to achieve the goal of musculoskeletal rehabilitation, but inadequate exercise planning can cause injuries. This study investigated changes in the electromyogram and joint moments of force (JMOFs) of lower extremities during common standing yoga poses in order to explore the feasibility and possible injury risk in dealing with musculoskeletal problems. Eleven yoga instructors were recruited to execute five yoga poses (Chair, Tree, Warrior 1, 2, and 3). The results revealed significant differences in hip, knee, and ankle JMOFs and varying degrees of muscle activation among the poses. Among these poses, rectus femoris muscle activation during the Chair pose was the highest, Warrior 2 produced the highest muscle activation in the vastus lateralis of the front limb, while Warrior 1 had the highest muscle activation in the vastus medialis of the back limb. Therefore, all three poses can possibly be suggested as a therapeutic intervention for quadriceps strengthening. Warrior 1 was possibly suggested as a therapeutic intervention in order to reduce excessive lateral overload of the patella, but the possible adverse effects of Warrior 2 with the highest knee adductor JMOF in the back limb could raise joint reaction forces across the medial condyles. In single-leg balance postures, Warrior 3 had unique training effects on the hamstring, and is therefore suggested as a part of hamstring rehabilitation exercises. The Tree pose induced low lower-extremity JMOFs and a low level of thigh muscle activations when it was performed by senior instructors with excellent balance control, however, for yoga beginners with insufficient stability, it will be a useful training mode for strengthening the muscles that help to keep one upright. This study quantified the physical demands of yoga poses using biomechanical data and elucidated the structures and principles underlying each yoga movement. This is crucial for yoga practitioners.

BACKGROUND: In medial knee osteoarthritis (knee OA), compensatory overstrain of the rectus femoris (RF) muscle leads to its hypertrophy. We hypothesize that besides hypertrophy of the RF, a prominent flattening of the central aponeurosis (CA) curvature is also indicative of RF. This study aims to evaluate the structural changes in the CA and clarify the conditions associated with RF overstrain in knee OA. OBJECTIVE: Twenty-three legs of 20 elderly without knee OA (elderly group) and 26 legs of 20 individuals with K-L grade II knee OA (knee OA group) with typical “comma”-shaped CA participated in this study. METHODS: The knee extension torque (Nm/kg) in the sitting position, the thickness of the RF and vastus intermedius (VI) muscles (VI), and change in CA curvature (%Curvature) were measured at the mid-thigh by ultrasonography. RESULTS: The knee extension torque was not significantly different between the two groups. Compared to the elderly group, the knee OA group had significantly thicker RF at rest, while the VI thickness during contraction was significantly smaller. The %Curvature was significantly higher in the knee OA group than in the elderly group. CONCLUSIONS: In the knee OA group, the RF was hypertrophic with a more pronounced CA flattening during muscle contraction, although the other quadriceps muscles were atrophic, suggesting an overstrained RF. Assessing thickness and CA curvature of the RF is, therefore, useful and simple for evaluating overstrain caused by RF compensation.

To determine the incidence of the iliocapsularis muscle in fetal period and its relationship with the hip joint capsule. Twenty-one formalin-fixed fetuses (12 female and 9 male) with a mean gestational age of 29 ± 3.89 weeks (range 25–36) were dissected to reveal morphological properties of iliocapsularis muscle. Iliocapsularis muscle was observed in 39 out of 42 sides (92%). Its proximal attachment was detected either below the proximal attachment of rectus femoris muscle in 21 out of 39 sides (54%), or it was forming a common tendon with rectus femoris on the anterior inferior iliac spine in 10 out of 39 sides (26%), or it was forming an arch along the superior–medial–inferior sides of the proximal attachment of rectus femoris muscle in 8 out of 39 sides (20%). Muscle fibers originating from the anteromedial part of hip joint capsule were also constant in all sides. Distal attachment of iliocapsularis muscle was distal to the lesser trochanter in all specimens. Its form was as a broad muscle in 32 out of 39 sides (82%) and as a thin rectangular muscular slip in 7 out of 39 sides (18%). Iliopsoas and iliocapsularis muscles had their particular fascia in 34 out of 39 sides (87%), and in the other 5 sides, there was no fascia which prominently separated the two muscles. Its length was longer in females than males (p = 0.031) and it was wider on the right side (p = 0.029). Linear functions were y = 0.49 + 0.17 × weeks and y = 6.94 + 0.89 × weeks for width and length, respectively. Data obtained with the present study about iliocapsularis muscle in fetal period revealed that it is an individual and constant muscle. Its dimension, location, and course over the hip joint capsule support the idea that it tightens the hip capsule and stabilizes the femoral head.

Objectives To compare hip flexor muscle cross-sectional area (CSA) in ballet dancers and athletes, and to evaluate the relationship between hip flexor size and hip pain. Study design Case control study. Setting Elite ballet and sport. Participants 33 professional ballet dancers and 33 age and sex-matched athletes. Main outcome measures CSA's of hip flexor muscles iliopsoas, rectus femoris, sartorius and tensor fascia latae (TFL) on magnetic resonance imaging (MRI) of one hip. Hip pain was scored with the Copenhagen Hip and Groin Outcome Score (HAGOS): HAGOS pain score of 100 was defined as no pain and a score less than 100 was defined as pain. Participants' weight and height. Results Dancers had larger iliopsoas (P Conclusion Ballet appears to selectively load iliopsoas, TFL and sartorius muscles but not rectus femoris. Iliopsoas muscle size was smaller in participants with hip pain, but TFL, sartorius and rectus femoris muscle size was not related to hip pain.

Sarcopenia is a geriatric syndrome related to loss of muscle mass and function, leading to disability, frailty and higher mortality. According to European Working Group on Sarcopenia in Older People (EWGSOP) the diagnosis of sarcopenia requires the assessment of muscle mass, muscle force and function, that is time-consuming and not easily at hand in everyday clinical practice. We propose the B-mode ultrasound measurement of muscle thickness as a quick screening test to assess the presence of sarcopenia.A cross-sectional study was realized, 119 patients (average age 82 years, 50.4% females) from the Department of Internal Medicine of the University Hospital of Siena (Italy) were enrolled. The diagnosis of sarcopenia was assessed according to EWGSOP criteria. Rectus femoris muscle (RFM) thickness (in cm) was measured by ultrasound B-mode scanning. Sensibility and specificity of the test was evaluated and Receiver Operating Analysis (ROC) was performed to assess the accuracy of the test.Average RFM thickness was 0.78 ± 0.26, significantly lower in sarcopenic patients (0.55 ± 0.2 vs. 0.9 ± 0.3; Mann-Whitney; p 0.001) and females (0.7 ± 0.3 vs 0.86 ± 0.3; Mann-Whitney; p 0.001). The cut-off point of 0.7 cm for females and 0.9 cm for males was established as a threshold to assess the presence of sarcopenia by ultrasound. Sensibility of ultrasound measurement of RFM thickness was 100%, specificity 64%, positive predictive value (PPV) 64.3% and negative predictive value (NPV) 100%. ROC analysis was performed in order to quantify how accurately RFM thickness can discriminate between sarcopenia and non-sarcopenia state. AUC for all patients was 0.9 and after a comparative analysis for gender higher values for males (0.94 vs. 0.92) were observed.We suggest a screening test for sarcopenia based on the ultrasound measurement of RFM thickness, as a not invasive and easy to perform method even in elderly patients with functional or cognitive impairment.

Background There is accumulating evidence for the advantages of rehabilitation involving sensori-motor training (SMT) following total knee replacement (TKR). However, the best way in which to deliver SMT remains elusive because of potential interference effects amongst concurrent exercise stimuli for optimal neuromuscular and morphological adaptations. The aim of this study was to use additional outcomes (i.e. muscle strength, activation and size) from a published parent study to compare the effects of early-initiated home-based rehabilitative SMT with functional exercise training (usual care) in patients undergoing TKR. Methods A controlled clinical trial was conducted at the Orthopedic University Hospital of Rion, Greece involving allocation concealment to patients. Fifty-two patients electing to undergo TKR were randomised to either early-initiated SMT [experimental] or functional exercise training [control] in a home-based environment. Groups were prescribed equivalent duration of exercise during 12-weeks, 3–5 sessions of ~ 40 min per week of home-based programmes. Muscle strength and activation (peak force [PF]; peak amplitude [Peak Amp.] and root mean square of integrated electromyography [RMS iEMG]), muscular size (including rectus femoris muscle cross-sectional area [CSARF]), and knee ROM were assessed on three separate occasions (pre-surgery [0 weeks]; 8 weeks post-surgery; 14 weeks post-surgery). Results Patients undertaking SMT rehabilitation showed significantly greater improvements over the 14 weeks compared to control in outcomes including quadriceps PF (25.1 ± 18.5 N vs 12.4 ± 20.8 N); iPeak Amp. (188 ± 109.5% vs 25 ± 105.8%); CSARF (252.0 ± 101.0 mm2 vs 156.7 ± 76.2 mm2), respectively (p

Objectives The purpose of this study was to develop an automatic tracking method for the muscle cross-sectional area (CSA) on ultrasound (US) images using a convolutional neural network (CNN). The performance of the proposed method was evaluated and compared with that of the state-of-the art muscle segmentation method. Methods A real-time US image sequence was obtained from the rectus femoris muscle during voluntary contraction. A CNN was built to segment the rectus femoris muscle and calculate the CSA in each US frame. This network consisted of 2 stages: feature extraction and score map reconstruction. The training of the network was divided into 3 steps with output score map resolutions of one-fourth, one-half, and all of the original image. We evaluated the segmentation performance of our method with 5-fold cross-validation. The mean precision, recall, and dice similarity score were calculated. Results The mean precision, recall, and Dice's coefficient (DSC) ± SD were 0.936 ± 0.029, 0.882 ± 0.045, and 0.907 ± 0.023, respectively. Compared with the state-of-the-art muscle segmentation method (constrained mutual-information-based free-form deformation), the proposed method using CNN showed high performance. Conclusions The automated method proposed in this study provides an accurate and efficient approach to the estimation of the muscle CSA during muscle contraction.

Our group has previously found that in silico, mechanical anisotropy may be interrogated by exciting transversely isotropic materials with geometrically asymmetric acoustic radiation force excitations and then monitoring the associated induced displacements in the region of excitation. We now translate acoustic radiation force-based anisotropy assessment to human muscle in vivo and investigate its clinical relevance to monitoring muscle degeneration in Duchenne muscular dystrophy (DMD). Clinical anisotropy assessments were performed using Viscoelastic Response ultrasound, with a degree of anisotropy reflected by the ratios of Viscoelastic Response relative elasticity (RE) or relative viscosity (RV) measured with the asymmetric radiation force oriented parallel versus perpendicular to muscle fiber alignment. In vivo results from rectus femoris and gastrocnemius muscles of boys aged ∼7.9–10.4 y indicate that RE and RV anisotropy ratios in rectus femoris muscles of boys with DMD were significantly higher than those of healthy control boys (RE: DMD = 1.51 ± 0.87, control = 0.99 ± 0.69, p = 0.04, Wilcoxon rank sum test; RV: DMD = 1.04 ± 0.71, control = 0.74 ± 0.22, p = 0.02). In the gastrocnemius muscle, only the RV anisotropy ratio was significantly higher in dystrophic than control patients (DMD = 1.23 ± 0.35, control = 0.88 ± 0.31, p = 0.04). In the dystrophic rectus femoris muscle, the RE anisotropy ratio was inversely correlated (slope = –0.03/lbf, r = –0.43, p = 0.07, Pearson correlation) with quantitative muscle testing functional output measures but was not correlated with quantitative muscle testing in the dystrophic gastrocnemius. These results suggest that Viscoelastic Response RE and RV measures reflect differences in mechanical anisotropy associated with functional impairment with dystrophic degeneration that are relevant to monitoring DMD clinically.

This study is a randomized controlled clinical trial that verified the resistance training efficacy on neuromuscular parameters, with muscle quality as primary outcome. Forty-four elderly with diabetes type 2 (69.7 ± 6.9 years; 26 men) were randomly allocated to a 12-weeks resistance training group (RTG, 3 times a week), or an active control group with stretching classes (CG, once a week). Primary and secondary outcomes were assessed at baseline and after 12 weeks, as follow: quadriceps muscle thickness and rectus femoris muscle quality, maximal knee extension strength, rapid strength, functional performance, visceral adipose tissue, glycemic control, lipid profile and quality of life. Generalized estimating equations were used to analyses based on intention-to-treat and per-protocol approaches, which showed the same results. Among all outcomes measured there were improvements in the knee extension strength (P < 0.001) and quadriceps muscle thickness (P < 0.001) for RTG. The muscle quality did not improve for both groups (P = 0.98). For the secondary outcomes there were no improvements for functional performance, rapid strength, glycemic control, quality of life, visceral adipose tissue and lipid profile in both groups, with exception of triglyceride level reduction for RTG (P = 0.04).The resistance training program is an efficacious strategy for improve the neuromuscular health in elderly with T2DM, considering increases in lower limb strength and muscle mass, but the same was not found for muscle quality, rapid strength, functional performance and quality of life. Furthermore, the training program did not induce significant reduction in glycated hemoglobin values of patients who already had suitable glycemic control.

The primary purpose was to examine the relationship between the muscle architectural characteristics of short and long-distance cyclist—including muscle thickness, fascicle angle, and fascicle length—of the anterior thigh and posterior leg and its impact in 20-s cycling power. The secondary purpose was to clarify the muscle variables that predict the cycling power by using ultrasonography to measure the muscle architectural characteristics. Twenty-four varsity cyclists participated in this study, of whom 12 were short-distance cyclists and 12 were long-distance cyclists. B-mode ultrasonography was used to measure muscle architecture parameters. A cycle ergometer was used to measure the cycling power. The rectus femoris, vastus medialis, and medial head of gastrocnemius were significantly thicker in short-distance cyclists than in long-distance cyclists at every site (p

AimThis study aims to simultaneously record the magnetic and electric components of the propagating muscular action potential.MethodA single-subject study of the monosynaptic stretch reflex of the musculus rectus femoris was performed; the magnetic field generated by the muscular activity was recorded in all three spatial directions by five optically pumped magnetometers. In addition, the electric field was recorded by four invasive fine-wire needle electrodes. The magnetic and electric fields were compared, and modelling and simulations were performed to compare the magnetic field vectors with the underlying muscular anatomy of the rectus femoris muscle.ResultsThe magnetomyography (MMG) signal can reliably be recorded following the stimulation of the monosynaptic stretch reflex. The MMG signal shows several phases of activity inside the muscle, the first of which is the propagating muscular action potential. As predicted by the finite wire model, the magnetic field vectors of the propagating muscular action potential are generated by the current flowing longitudinal to the muscle fiber. Based on the magnetic field vectors, it was possible to reconstruct the pinnation angle in the muscle. The later magnetic components are linked to the activated contractile apparatus.InterpretationMMG allows to analyze the muscle physiology from the propagating muscular action potential to the initiation of the contractile apparatus. At the same time this methods reveal information about muscle fiber direction and extend. With the development of high-resolution magnetic cameras, it will be possible to image the function and structure of any skeletal muscle with high precision. This method could be used in clinical medicine but also in sports and training science.What this paper adds-A robust technique for triggering a muscular action potential that can be recorded by MMG and needle EMG simultaneously-The correlation of the MMG signal with the needle EMG signal-A method for detecting the direction of the propagating muscular action potential-A method for correlating the magnetic field vectors with the pinnation angle of the examined muscle

The prototype machine of gait training and rehabilitation (MGTR) with a five-bar linkage structure was designed to improve the common end-effector type. Additionally, the study was conducted to evaluate the joint angle and muscle activity during walking for the evaluation of prototype: (1) Background: The gait rehabilitation systems are largely divided into exoskeletal type and end-effector type. The end-effector type can be improved a gait trajectory similar to normal gait according to this prototype. Therefore, a new design of prototype MGTR is proposed in this study. (2) Methods: The gait experience was conducted with thirteen healthy male subjects using an inertial measurement unit (IMU) sensor and electromyography (EMG). It was compared that the hip and knee joints and the muscle activity between the normal gait and MGTR. (3) Results: The results showed that there was a high correlation between the knee joint angle for normal gait and MGTR. The range of motion (RoM) was small for the MGTR. The EMG results showed that the activation of the rectus femoris muscle was most similar to the normal gait and MGTR. (4) Conclusions: The characteristics of the kinematic variables of the subjects varied widely. It is necessary to modify the machine so that the link length can be adjusted in consideration of various segment lengths of patients.

INTRODUCTION Disuse syndrome due to immobility and/or prolonged bed rest is characterized by the deterioration of body systems secondary to musculoskeletal inactivity (). The consequences of prolonged bed rest and lack of physical activity include effects on cognition, muscles, bones and joints, and skin, as well as the cardiovascular and respiratory systems (). Differences in loss and atrophy among various muscles can be explained by their fiber characteristics and functions. For instance, the rectus femoris muscle, which performs primarily fast [...]

Maintaining adequate body water balance is one aim of hemodialysis that is obtained by changing the blood volume. However, it is known that volume withdrawal is followed by water redistribution between extra- and intra-cellular spaces. In this context, the skeletal muscle tissue represents almost 50% of the total body mass, and like other soft tissues, consists of about 70%-80% water. Body weight is the main parameter used to monitor the body water change after a hemodialysis session, but it does not allow inferring about the water redistribution between extra and intracellular spaces. Thus, the present study aimed to assess the immediate impact of hemodialysis on body weight and the thickness of the rectus femoris muscle. Fifteen male patients with end-stage renal disease took part in the study. Muscle thickness, measured with ultrasound imaging, and body weight and were measured before (Pre) and after (Post) (within 5 to 10 minutes after) an hemodialysis session. Paired t-test was used to compare Pre and Post measures, and Bayesian analysis was applied to check the probability to replicate the same results (ie, the magnitude of the evidence). Our results indicated that body weight, but not rectus femoris muscle thickness, is significantly reduced immediately after hemodialysis. The rectus femoris muscle thickness seems not to be a reliable parameter to infer water redistribution after hemodialysis session.

INTRODUCTION: Eccentric training has been associated with several specific physiological adaptations. The flywheel machine is one of the easiest ways of performing eccentric overload training. However, no studies evaluated its feasibility, safety and muscle activity in patients with haemophilia (PWH).AIM: To evaluate feasibility and safety and compare muscle activity during flywheel vs weight machine knee extension exercise in severe PWH.METHODS: Eleven severe PWH [mean age of 33.5 (8.1) years] participated in this cross-sectional study after receiving prophylactic treatment. Surface electromyography (EMG) signals were recorded for the rectus femoris during the knee extension exercise performed with 2 different conditions (flywheel and weight machine) with matched intensity (6 on the Borg CR10 scale). Kinesiophobia was assessed before and after the experimental session. Participants were asked to rate tolerability of each condition. Adverse effects were evaluated 24 and 48 hours after the session.RESULTS: Kinesophobia did not increase after the experimental session, and no adverse effects were reported. At 60%-70% of the contraction cycle, the flywheel exercise showed higher (P = .024) eccentric rectus femoris muscle activity than the weight machine. In contrast, during the last 90%-100% of the contraction cycle, the traditional weight machine showed higher (P = .004) rectus femoris activity than the flywheel.CONCLUSION: The knee extension exercise performed with the flywheel at moderate intensity is safe and well tolerated among severe PWH under adequate factor coverage. Importantly, the flywheel variation provides higher eccentric rectus femoris activity at the breaking force moment, while it provides lower eccentric muscle activity at the end of the cycle.

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.

The knee extensor mechanism is a highly complex multilayered and reinforced structure. Quadriceps muscle injuries are considered to be common, particularly among athletes; however isolated rectus femoris injuries involving the distal myotendinous junction are considered to be exceedingly rare with very few case reports published to date. Thus, the presentation and diagnosis of this injury can be elusive and treatment is nonuniform. There is limited literature published advocating both nonsurgical and surgical management. We illustrate the clinical and radiologic presentation of a traumatic, nonsport-related distal rectus femoris muscle injury treated operatively. The presentation of this injury along with anatomical and clinical considerations is portrayed in detail. This case report contributes to the sparse literature regarding this injury and delineates management considerations.

Objective: Although skeletal muscle atrophy is common in critically ill patients, biomarkers associated with muscle atrophy have not been identified reliably. Titin is a spring-like protein found in muscles and has become a measurable biomarker for muscle breakdown. We hypothesized that urinary titin is useful for monitoring muscle atrophy in critically ill patients. Therefore, we investigated urinary titin level and its association with muscle atrophy in critically ill patients. Design: Two-center, prospective observational study Setting: Mixed medical/surgical intensive care unit (ICU) in Japan Patients: Nonsurgical adult patients who were expected to remain in ICU for >5 days Interventions: None Methods: Urine samples were collected on days 1, 2, 3, 5, and 7 of ICU admission. To assess muscle atrophy, rectus femoris cross-sectional area and diaphragm thickness were measured with ultrasound on days 1, 3, 5, and 7. Secondary outcomes included its relationship with ICU-acquired weakness (ICU-AW), ICU Mobility Scale (IMS), and ICU mortality. Measurements and Main Results: Fifty-six patients and 232 urinary titin measurements were included. Urinary titin (normal range: 1–3 pmol/mg Cr) was 27.9 (16.8–59.6), 47.6 (23.5–82.4), 46.6 (24.4–97.6), 38.4 (23.6–83.0), and 49.3 (27.4–92.6) pmol/mg Cr on days 1, 2, 3, 5, and 7, respectively. Cumulative urinary titin level was significantly associated with rectus femoris muscle atrophy on days 3–7 (p < 0.03), although urinary titin level was not associated with change in diaphragm thickness (p = 0.31–0.45). Furthermore, cumulative urinary titin level was associated with incidence of ICU-AW (p = 0.01) and ICU mortality (p = 0.02) but not with IMS (p = 0.18). Conclusions: In nonsurgical critically ill patients, urinary titin level increased 10–30 times compared with the normal level. The increased urinary titin level was associated with lower limb muscle atrophy, incidence of ICU-AW, and ICU mortality.

Context: Fast and adequate recovery after exercise and activity is important for increasing performance and preventing injuries. Inadequate recovery usually causes changes in the biomechanical and viscoelastic properties of the muscle. Objective: To compare the immediate effect of petrissage massage (PM) and manual lymph drainage (MLD) following submaximal exercise on the biomechanical and viscoelastic properties of the rectus femoris muscle in healthy women. Design: Cross-sectional, repeated-measures. Setting: Marmara University. Participants: 18 healthy female students. Intervention(s): Following the submaximal quadriceps strengthening exercise performed in 3 sets of 8 repetitions with intensity of 75% of 1 maximum repetition, participants’ right leg received a 5-minute PM (PM group) and the contralateral leg received a 5-minute MLD application (MLD group). Main Outcome Measures: Skin temperature was measured using P45 thermographic thermal camera (Flir System; ThermaCAM, Danderyd, Sweden), and muscle tone, biomechanical, and viscoelastic features were measured with a myometer (Myoton AS, Tallinn, Estonia) at baseline, immediately postexercise, post-PM/MLD application, and 10 minutes postexercise. Results: In the PM group, the tonus (P = .002) and stiffness (P P P P P = .025), and relaxation time (P P Conclusion: PM and MLD reduce passive tissue stiffness and improve the extent of muscle extensibility over time against the muscle tensile strength. PM and MLD are therapeutic methods that can be used to support tissue recovery after exercise and prevent injuries.

Cold-water immersion (CWI) has become a popular preventive, regenerative and performance-enhancing intervention in various sports. However, its effects on soft tissue, including changes of intramuscular stiffness, are poorly understood. The purpose of this study was to investigate the effect of CWI on muscle stiffness. Thirty healthy participants were included and divided into the three following groups (n = 10): 1) post-ESU group: exercise and CWI (post-exercise set-up); 2) control group: exercise without CWI (control condition); 3) pre-ESU group: CWI alone (pre-exercise set-up). Acoustic radiation force impulse (ARFI) elastography was conducted to assess tissue stiffness (shear wave velocity, SWV). Values obtained at resting conditions (baseline, t0) were compared to values post-exercise (t1, for post-ESU group and control group), post-CWI (t2, for post-ESU group and pre-ESU group; rest for control group) and to 60-min follow-up time (t3, for all groups). Data were assessed in superficial and deep muscle tissue (rectus femoris muscle, RF; vastus intermedius muscle, VI). For the post-ESU group (CWI post-exercise), there was no significant difference between the time points of measurements: exercise (t1: RF: 1.63 m/s; VI: 1.54 m/s), CWI (t2: RF: 1.63 m/s; VI: 1.53 m/s) and at 60-min follow-up (t3: RF: 1.72 m/s; VI: 1.61 m/s). In the control group, a significant decrease of SWV was found between baseline conditions at t0 and post-exercise (t1) at VI (VI: 1.37 m/s; p = 0.004; RF: 1.59 m/s; p = 0.084). For t2 and t3, no further significant changes were detected. Regarding the pre-exercise set-up (pre-ESU group), a significant decrease in SWV from baseline to t2 in VI (1.60 m/s to 1.49 m/s; VI: p = 0.027) was found. This study shows varying influences of CWI on muscle stiffness. Overall, we did not detect any significant effects of CWI on muscle stiffness post-exercise. Muscle stiffness-related effects of CWI differ in the context of a pre- or post-exercise condition and have to be considered in the implementation of CWI to ensure its potential preventive and regenerative benefits. Die Kaltwasserimmersion (CWI) ist ein beliebtes präventives und regeneratives Therapieverfahren und hat sich in verschiedensten Sportarten etabliert. Die Effekte auf die Muskulatur sowie die Änderung der intramuskulären Gewebesteifigkeit sind jedoch ungeklärt. Ziel dieser Studie war es, den Einfluss einer Kaltwasserimmersionstherapie auf die Muskelsteifigkeit zu untersuchen. Insgesamt wurden 30 gesunde Athleten in 3 Gruppen (n = 10) aufgeteilt. 1) Post-ESU-Gruppe: Belastung und CWI; 2) Kontroll-Gruppe: Belastung ohne CWI; 3) Pre-ESU-Gruppe: CWI ohne Belastung. Die passive Muskelsteifigkeit wurde mittels Acoustic radiation force impulse (ARFI) Elasto-Sonografie anhand der Shear-Wave-Velocity (SWV) im M. rectus femoris (RF) und M. vastus intermedius (VI) bestimmt. Die Messwerte des Ausgangsniveaus (t0) wurden gruppenspezifisch mit den Werten nach der Belastung (t1, für Post-ESU-Gruppe und Kontroll-Gruppe) nach CWI (t2, für Post-ESU-Gruppe und Pre-ESU-Gruppe bzw. Kontrollzeit für Kontroll-Gruppe) und 60 min nach Intervention (t3, für alle Gruppen) verglichen. In der Post-ESU-Gruppe zeigte sich kein signifikanter Unterschied zwischen den Messzeitpunkten: Belastung (t1: RF: 1,63 m/s; VI: 1,54 m/s), CWI (t2: RF: 1,63 m/s; VI: 1,53 m/s;) und 60 min. nach Intervention (t3: RF: 1,72 m/s; VI: 1,61 m/s). In der Kontroll-Gruppe konnte eine signifikante Abnahme der SWV zwischen dem Ausgangsniveau t0 und t1 im VI beobachtet werden (VI: 1,37 m/s; p = 0,004) (RF: 1,59 m/s; p = 0,084). Zum Zeitpunkt t2 und t3 konnte keine weitere signifikante Änderung festgestellt werden. Eine signifikante Abnahme der SWV konnte in der Pre-ESU-Gruppe zwischen Ausgangsniveau (t0) und post-CWI (t2) im VI festgestellt werden (p = 0,027). Die vorliegende Studie zeigt unterschiedliche Einflüsse einer CWI auf die Muskelsteifigkeit. Insgesamt kann festgehalten werden, dass wir nach Belastung keinen signifikanten Effekt der CWI auf die Muskelsteife feststellen konnten. Die unterschiedlichen Effekte, abhängig vom Zustand vor oder nach Belastung, müssen bei der Durchführung bedacht werden, um einen möglichen präventiven und regenerativen Nutzen gewährleisten zu können.

This study aimed to determine (1) intramuscular regional differences in the changes in the shear modulus of the rectus femoris (RF) muscle during passive knee flexion and (2) the relationship between shear modulus and passive knee extension torque. The shear modulus maps as an index of muscle stiffness and the passive torque were obtained at seven regions during passive knee flexion at 2°/s within a knee joint range of motion of 0°–130° in 16 healthy males. The shear modulus of RF increased with the knee angle of flexion. The shear modulus of each longitudinal region was greater in the order of proximal, central, and distal region (p

Recent studies presented that increased adiposity and hyperlipidemia may cause tendon pathology. The aim of this study was to evaluate the effect of hyperlipidemia on the patellar tendon stiffness by shear wave elastography.A total of 51 participants (19 female, 32 male) were included. Participants were divided into two groups, according to their low-density lipoprotein levels, as the study group (hyperlipidemia, n = 24) and the control group (non-hyperlipidemia, n = 27). The patellar tendon and rectus femoris muscle shear wave velocities were measured by shear wave elastography.Patellar tendon shear wave velocities was 5.02 (SD: 0.78) m/s in the control group and 5.98 (SD: 1.19) m/s in the hyperlipidemia group (ES = 0.95, P = .001). There was a positive moderate statistically significant correlation between patellar tendon shear wave velocity and low-density lipoprotein (r = 0.432, p .002). In the multiple linear regression analysis, only low-density lipoprotein was found as a significant predictor of patellar tendon shear wave velocity (CI: 0.005-0.028, P = .007).We evaluated the effects of hyperlipidemia and body mass index on patellar tendon mechanical properties with shear wave elastography. We found that the blood low-density lipoprotein level had an impact on patellar tendon stiffness independently of body mass index. Accordingly, it is important to evaluate individuals' low-density lipoprotein levels when examining risk factors for tendon pathology.

Background: Adaptive balance control is often compromised in children with developmental coordination disorder (DCD). Neuromuscular training (NMT) is commonly used in clinical settings to improve neuromuscular control and hence balance performance in these children. However, its effectiveness has not been proven scientifically. This randomized controlled study aimed to explore the effectiveness of NMT for improving adaptive balance performance and the associated leg muscle activation times in children with DCD. Methods: Eighty-eight children with DCD were randomly assigned to the NMT or control group (44 per group). The NMT group received two 40-minute NMT sessions/week for 3 months, whereas the control group received no intervention. The outcomes were measured at baseline and 3 and 6 months. The primary outcome was the sway energy score (SES) in both the toes-up and toes-down conditions as derived using the Adaptation Test (ADT). Secondary outcomes included the medial gastrocnemius, medial hamstring, tibialis anterior and rectus femoris muscle activation onset latencies during ADT, measured using surface electromyography and accelerometry. Data were analyzed using a repeated measures analysis of covariance based on the intention-to-treat principle. Results: At 3 months, no significant within-group or between-group differences were noted in the SESs for either group. At 6 months, the toes-down SES decreased by 6.8% compared to the baseline value in exclusively the NMT group (P = .004). No significant time, group or group-by-time interaction effects were observed in any leg muscle activation outcomes. Conclusions: Short-term NMT failed to improve adaptive balance performance and leg muscle activation times in children with DCD. Further studies should explore the clinical applications of longer-term task-specific interventions intended to improve the adaptive balance performance of these children.

It is well known that several risk factors such as fatigue, previous injury, muscle strength deficit or imbalance are related to a higher incidence of knee injuries in professional soccer players. Knee muscle and tendon stiffness may be another factor that is related to knee injuries in professional soccer players. Therefore, the aim of the present study was to investigate the differences between professional soccer players and healthy sedentary males in terms of the stiffness of patellar tendon (PT), quadriceps tendon (QT), and rectus femoris muscle (RF) and vastus medialis muscle (VM).The study group was comprised of 17 professional male soccer players in age range of 24-37 years. The control group was comprised of 22 healthy sedentary males in an age range of 21-36 years. Shear-Wave Velocity (SWV) measurements of the selected muscles and tendons were performed using an ultrasonography device with a lineal probe.The professional soccer players had lower SWV of PT (P=0.024) and QT (P0.001) in the dominant leg compared to the control group; however, SWV of PT (P=0.455) and QT (P=0.827) in the non-dominant leg were similar in both groups. SWV of RF was higher in both dominant and non-dominant legs in professional soccer players compared to the control group (P0.05); however, SWV of VM was similar in both groups (P0.05).Professional soccer players had lower PT and QT stiffness. On the other hand, they had higher RF stiffness compared to sedentary individuals. Furthermore, VM stiffness was similar in both groups.

Background Rehabilitation according to Vojta is a neurophysiological method used to obtain reflex responses in muscles following stimulation of particular activation zones. Objectives This study aims to objectively evaluate the muscular responses following stimulation according to Vojta's method. The possible routes of spinal transmission responsible for the phenomenon of muscle activation in upper and lower extremities are considered. Methods Polyelectromyographic (pEMG) recordings in the upper and lower extremities in healthy volunteers (N = 25; aged 24 ± 1 year) were performed to find out the possible routes of spinal transmission, responsible for muscle activation. The left acromion and right femoral epicondyle were stimulated by a Vojta therapist; pEMG recordings were made including the bilateral deltoid and rectus femoris muscles. Results and discussion Following acromion stimulation, muscle activation was mostly expressed in the contralateral rectus femoris, rather than the contralateral deltoid and the ipsilateral rectus femoris muscles. After stimulation of the lower femoral epicondyle, the following order was observed: contra lateral deltoid, ipsilateral deltoid and the contra lateral rectus femoris muscle. One of the candidates responsible for the main crossed neural transmission involved in the Vojta therapy mechanism would be the long propriospinal tract neurons.

Introduction We investigated regional differences in amplitude modulation of the spinal reflex along the human rectus femoris (RF) muscle to test the hypothesis that this muscle is regionally regulated at the spinal cord or a higher level. Methods Surface electromyography was conducted at six different sites along the RF muscle during the conditioned patellar tendon reflex in eight healthy young men. Results A significant difference in the reflex amplitude among the channels was observed during 20% of the maximal voluntary contraction (MVC) and there was a significant difference in normalized reflex amplitude between 10 and 20% of the MVC at most proximal channel (p 0.05), during knee flexion of the ipsilateral leg. Discussion From the results in the present study, we infer that the amplitude modulation of the tendon reflex within the RF muscle is regionally regulated, and that this regulation is dependent on the performed tasks.

Muscle fatigue is a process influenced by several mechanisms such as concentration of metabolic substrates, changes in blood flow, and increases in reactive oxygen species that impair contractile muscle function. In this context, photobiomodulation has been investigated for preventing muscle fatigue, with reports of positive effects on muscle performance. This study aimed to investigate the effects of 904-nm LASER photobiomodulation on rectus femoris muscle performance in young women. Eighteen young women participated in a randomized, participant and assessor-blinded crossover trial with placebo control. Active LASER (904 nm, 60 mW, 250 Hz, 3.6 J per diode, total dose of 129.6 J) intervention was applied prior to an isokinetic fatigue protocol consisting of a set of 60 concentric quadricep contractions at a constant dynamometer angular velocity of 180°/s. Compared to placebo, LASER photobiomodulation significantly reduced muscle fatigue across a range of indicators including reduced ratings of perceived exertion (P = 0.0139), and increased electromyographic fatigue index (EFI) (P = 0.005). The isokinetic dynamometer performance analysis demonstrated that LASER photobiomodulation increased peak torque (P = 0.04), time to peak torque (P = 0.042), total work (P = 0.032), average power (P = 0.0007), and average peak torque (P = 0.019) between both experimental conditions. No significant difference was observed for work fatigue index (P = 0.29) or for lactate concentration (P > 0.05). Photobiomodulation at 904 nm was effective in reducing fatigue levels and increasing muscle performance in young active women but had no effect on lactate levels.

Objective Falls are the most common and expensive medical complication following stroke. Hypermetric reflexes have been suggested to impact post-stroke balance but no study has evaluated reflex amplitudes under real conditions of falls in this population. Our objective was to quantify the early reflexive responses during falls induced in the laboratory. Methods Sixteen stroke survivors were exposed to posteriorly directed treadmill perturbations that required a forward step to maintain a balance. Perturbations differed in terms of treadmill translation displacement, velocity, and acceleration. EMG amplitudes were compared between Fall/Recovery trials, as well as Fallers/Non-Fallers at two different time windows: 50–75 and 75–100 ms. Results Sixteen of 86 trials resulted in falls by nine subjects (Fallers). While no differences were found between 50 and 75 ms, EMG amplitude in the paretic rectus femoris muscle was larger between 75 and 100 ms during Fall trials. Further, a bilateral increase in RF activity was seen in Fallers but not Non-Fallers. Interestingly, the bilateral increase was related to perturbation intensity (larger EMG activity with larger perturbations) in Fallers, but again not in Non-Fallers. Conclusions Heightened early recovery hip flexor activity between 75 and 100 ms is associated with falls and Fallers post-stroke. Significance Though requiring replication and expanded subject pools, these preliminary results reflect a possible clinically meaningful relationship between heightened reflexive responses and fall risk. Future work should evaluate the underlying mechanisms driving these heightened reflexes (e.g. stretch, startle) such that future rehabilitation techniques can address this abnormal response.

Khan, FL, Lawal, JM, Kapture, DO, Swingle, JD, and Malek, MH. Revisiting the single-visit protocol for determining the electromyographic fatigue threshold. J Strength Cond Res 31(12): 3503-3507, 2017-The electromyographic fatigue threshold (EMGFT) has been shown to demarcate between nonfatiguing and fatiguing exercise workloads. One potential limitation of incorporating the single EMGFT test in a clinical setting is the 2-minute stage increment inherit to the protocol. In most rehabilitation clinics, time with the client is limited, and any testing procedure needs to consider this factor. The purpose of this study, therefore, was to determine whether or not the estimation of the EMGFT is influenced by reducing the incremental stage to 1-minute intervals. We hypothesized that the 1-minute incremental protocol would provide similar estimates of the EMGFT as the traditional 2-minute incremental protocol. Nine college-aged men performed the single-leg knee-extensor ergometry at 1-minute (3 W) and 2-minute (6 W) stages in random order separated by 7 days. The exercise indices and the EMGFT were determined from the 2 protocols and analyzed using a paired samples t test. The EMG amplitude was assessed from the rectus femoris muscle. The results indicated significant differences between protocols for maximal power output (1 minute: 31.7 ± 2.2 W vs. 2 minutes: 38.0 ± 3.3 W, p = 0.016) and heart rate at end exercise (1 minute: 137 ± 5 b·min vs. 2 minutes: 148 ± 5 b·min, p = 0.024). There were, however, no significant mean differences for the EMGFT (1 minute: 19.8 ± 1.8 vs. 2 minutes: 20.3 ± 1.9 W, p = 0.63) and rating of perceived exertion (RPE) for the exercised leg (1 minute: 9 ± 0 vs. 2 minutes: 9 ± 1, p = 0.68). These results indicate that reducing the exercise protocol by 50% did not change the estimated EMGFT. The practical application of this finding resides in the potential use in sports or rehabilitative settings in which there is limited time with the client and no objective measures to determine neuromuscular fatigue for aerobic exercise.