Use of Biologics for the Treatment of Inflammatory Conditions of the Pouch: A Systematic Review.

BACKGROUND: Patients with medically-refractory ulcerative colitis or advanced neoplasia are often offered an ileal-pouch-anal anastomosis to restore bowel continuity. However, up to 50% of patients can suffer from inflammatory conditions of the pouch, some of which require biological therapy to treat. The aim of this study was to determine the efficacy of each biological agent for the treatment of inflammatory conditions of the pouch. MATERIALS AND METHODS: A comprehensive literature search was performed in the major databases from inception through February 11, 2020, for studies assessing the efficacy of biologics in chronic antibiotic-refractory pouchitis (CARP) and Crohn's disease (CD) of the pouch. Both prospective and retrospective studies were included. The primary outcomes of interest were complete and partial responses were defined within each study. χ 2 test was used to compare variables. RESULTS: Thirty-four studies were included in the systematic review and meta-analysis. Sixteen studies (N=247) evaluated the use of infliximab (IFX), showing complete response in 50.7% and partial response in 28.1% for CARP, and complete response in 66.7% and partial response in 20% for CD of the pouch. Seven studies (n=107) assessed the efficacy of adalimumab. For CARP, 33.3% of patients had a complete response, and 38.1% had a partial response, whereas for CD of the pouch, 47.7% experienced a complete response, and 24.6% had a partial response. Three studies (n=78) reported outcomes with the use of ustekinumab, showing 50% complete response and 3.8% partial response for CARP. For the CD of the pouch, 5.8% had a complete response and 78.8% had a partial response. Seven studies (n=151) reported the efficacy of vedolizumab, showing 28.4% complete response and 43.2% partial response in patients with CARP, whereas 63% of patients experienced partial response in CD of the pouch. IFX had higher rates of complete response in CARP compared with adalimumab ( P =0.04) and compared with vedolizumab ( P =0.005), but not compared with ustekinumab ( P =0.95). There were no new safety signals reported in any of the studies. CONCLUSIONS: Biologics are safe and efficacious in the treatment of chronic, refractory inflammatory conditions of the pouch. IFX seems to be more efficacious than adalimumab and vedolizumab for CARP. Further prospective, head-to-head evaluations are needed to compare biological therapies in the treatment of CARP and CD of the pouch.

Regulatory Light-Chain Phosphorylation During Weightlifting Training: Association With Postactivation Performance Enhancement.

ABSTRACT: Chiu, LZF, Fry, AC, Galpin, AJ, Salem, GJ, and Cabarkapa, D. Regulatory light-chain phosphorylation during weightlifting training: association with postactivation performance enhancement. J Strength Cond Res 37(10): e563-e568, 2023-Postactivation performance enhancement has been reported for multijoint resistance exercise, with both neural and intrinsic muscle mechanisms suggested as contributing factors. The purpose of this investigation was to examine whether regulatory light-chain (RLC) phosphorylation in a primary mover is associated with enhanced weightlifting performance. Nine male athletes performed 15 sets of 3 repetitions of a multijoint weightlifting activity (clean pull) at 85% 1 repetition maximum. Measures of performance, peak barbell velocity (PV), and average barbell power (AP) were determined by video analysis. Muscle biopsies were taken within 30-60 seconds of completion of the previous lifting set from the vastus lateralis before (PRE), during (MID), and after (POST) a training session. AP was significantly greater for sets 3, 4, and 5 compared with set 1, with large effect sizes (0.8-1.0). Increases in PV did not reach significance; however, the effect size increase for sets 3 and 4 versus set 1 was moderate (0.4). Relative change scores for AP and RLC phosphorylation were positively and negatively correlated at MID (r = 0.60; p = 0.05) and POST (r = -0.74; p = 0.01) exercise, respectively. These data suggest that RLC phosphorylation initially may be associated with postactivation performance enhancement during repeated multijoint exercise.

A Novel Patient-like Swine Model of Perianal Crohn's Disease.

BACKGROUND: Perianal Crohn's disease is associated with poor outcomes and high medical costs. It is notoriously difficult to treat despite therapeutic advancements for luminal disease. A large animal model that mimics human perianal disease is needed to test innovative therapies. OBJECTIVE: This study aimed to create a swine model that replicates the inflammatory component and therapeutic challenges found in patients with perianal Crohn's disease. DESIGN: This was an animal preclinical study. SETTINGS: The experiments were performed at the animal laboratory at the Johns Hopkins University. PATIENTS: Four sus scrufus female pigs were included in the study. INTERVENTIONS: Four female pigs underwent creation of 3 surgical perianal fistulas each, 1 rectovaginal and 2 perianal. Size 24 French setons were placed to maintain patency of the fistula tracts for 4 weeks. After removal of the setons, trinitrobenzene sulfonic acid was administered into the fistula tract to create and maintain local inflammation mimicking perianal Crohn's disease. MAIN OUTCOMES MEASURES: An MRI was obtained to assess the fistulas and the pigs were euthanized to review histopathology. RESULTS: Three inflammatory chronic fistula tracts were successfully created in each pig as confirmed by MRI and examination under anesthesia. This is the first report of maintaining patent fistulas in swine 2 weeks after removal of setons. For the first time, we reported that 2 pigs developed branching fistulas and small abscesses reminiscent of human perianal Crohn's disease. The corresponding histopathologic examination found significant chronic active inflammation on standard hematoxylin and eosin staining. LIMITATIONS: The fistulas were surgically induced and did not occur naturally. CONCLUSIONS: A chronic perianal fistula model in pigs that strongly resembles human perianal Crohn's disease was successfully created. This model can be used to test novel therapeutics and techniques to pave the path for human trials. See Video Abstract at http://links.lww.com/DCR/B969 . UN NUEVO MODELO PORCINO SIMILAR A UN PACIENTE DE LA ENFERMEDAD DE CROHN PERIANAL ANTECEDENTES: La enfermedad de Crohn perianal se asocia con malos resultados y altos costos médicos. Es notoriamente difícil de tratar a pesar de los avances terapéuticos para la enfermedad luminal. Se precisa de un modelo animal grande que imite la enfermedad perianal humana para probar terapias innovadoras.OBJETIVO:Nuestro objetivo de este estudio fue crear un modelo porcino que replique el componente inflamatorio y los desafíos terapéuticos que se encuentran en los pacientes con enfermedad de Crohn perianal.DISEÑO:Este fue un estudio preclínico en animales.AJUSTES:Los experimentos se realizaron en el laboratorio de animales de la Universidad Johns Hopkins.PACIENTES:Se incluyeron en el estudio cuatro cerdas sus scrofa.INTERVENCIONES:Cuatro cerdas fueron sometidas a la creación de 3 fístulas perianales quirúrgicas cada una: 1 recto vaginal y 2 perianales. Se colocaron sedales de 24 French para mantener la permeabilidad de los trayectos fistulosos durante 4 semanas. Tras el retiro de los sedales, se administró ácido trinitrobenceno sulfónico en el trayecto de la fístula para crear y mantener la inflamación local simulando la enfermedad de Crohn perianal.PRINCIPALES MEDIDAS DE RESULTADOS:Se obtuvo una resonancia magnética para evaluar las fístulas y los cerdos fueron sacrificados para revisar la histopatología.RESULTADOS:Se crearon de manera exitosa tres trayectos fistulosos inflamatorios crónicos en cada cerdo, confirmados por imágenes de resonancia magnética y examen bajo anestesia. Este es el primer informe de preservación de fístulas permeables en cerdos 2 semanas tras el retiro de los setones. Por primera vez, informamos que dos cerdos desarrollaron fístulas ramificadas y pequeños abscesos que recuerdan a la enfermedad de Crohn perianal humana. El examen histopatológico correspondiente encontró una significativa inflamación crónica activa en la tinción estándar de hematoxilina y eosina.LIMITACIONES:Las fístulas se indujeron quirúrgicamente y no se produjeron de forma natural.CONCLUSIONES:Se logro recrear con éxito un modelo de fístula perianal crónica en cerdos que se asemeja mucho a la enfermedad de Crohn perianal humana. Este modelo se puede utilizar para probar nuevas terapias y técnicas para allanar el camino para los ensayos en humanos. Consulte Video Resumen en http://links.lww.com/DCR/B969 . (Traducción-Dr Osvaldo Gauto).

Advances in Imaging of Inflammation, Fibrosis, and Cancer in the Gastrointestinal Tract.

Gastrointestinal disease is prevalent and broad, manifesting itself in a variety of ways, including inflammation, fibrosis, infection, and cancer. However, historically, diagnostic technologies have exhibited limitations, especially with regard to diagnostic uncertainty. Despite development of newly emerging technologies such as optoacoustic imaging, many recent advancements have focused on improving upon pre-existing modalities such as ultrasound, computed tomography, magnetic resonance imaging, and endoscopy. These advancements include utilization of machine learning models, biomarkers, new technological applications such as diffusion weighted imaging, and new techniques such as transrectal ultrasound. This review discusses assessment of disease processes using imaging strategies for the detection and monitoring of inflammation, fibrosis, and cancer in the context of gastrointestinal disease. Specifically, we include ulcerative colitis, Crohn's disease, diverticulitis, celiac disease, graft vs. host disease, intestinal fibrosis, colorectal stricture, gastric cancer, and colorectal cancer. We address some of the most recent and promising advancements for improvement of gastrointestinal imaging, including unique discussions of such advancements with regard to imaging of fibrosis and differentiation between similar disease processes.

Persons with patellar tendinopathy exhibit anatomical features that alter knee extensor mechanics: A comparison of persons with and without symptoms.

It has been postulated that anatomical features of the patellofemoral joint may alter knee extensor mechanics in a way that may contribute to excessive patellar tendon loading. The purpose of this study was to compare the knee extensor mechanics in persons with and without patellar tendinopathy. Twenty-eight individuals participated (14 with patellar tendinopathy and 14 pain-free controls). Sagittal magnetic resonance images of the knee were acquired at the knee flexion angle that corresponded to the knee flexion angle at the time of peak knee extensor moment during a single-leg landing task. Measurements of patellar tendon/quadriceps tendon force ratio, quadriceps moment arm, patellar tendon moment arm, and patellar height (Insall-Salvati ratio) were obtained. Independent t-tests were used to compare the variables of interest between groups. When compared to the control group, the patellar tendinopathy group exhibited significantly a greater patellar tendon/quadriceps tendon force ratio (Mean ± SD, 1.0 ± 0.1 vs 0.8 ± 0.1, p < 0.05), a larger quadriceps moment arm (Mean ± SD, 23.9 ± 2.0 mm vs 22.1 ± 2.9 mm, p < 0.05), a smaller patellar tendon moment arm (Mean ± SD, 24.2 ± 1.7 mm vs 26.3 ± 2.4 mm, p < 0.05) and a greater Insall-Salvati ratio (Mean ± SD, 1.2 ± 0.1 vs 1.1 ± 0.1, p < 0.05). These results suggest that persons with patellar tendinopathy may experience greater forces in the patellar tendon for a given level of quadriceps force.

Ustekinumab is effective for perianal fistulising Crohn's disease: a real-world experience and systematic review with meta-analysis.

BACKGROUND: Perianal Crohn's disease (pCD) is a debilitating complication affecting up to 30% of Crohn's disease (CD) population, leading to increased morbidity, mortality and decreased quality of life. Despite the growing armamentarium of medications for luminal CD, their efficacy in pCD remains poorly studied. AIM: To determine the efficacy of ustekinumab, a biologic approved for luminal CD, in pCD through a retrospective cohort study and systematic review. METHODS: A retrospective cohort study on patients with CD with active perianal fistulae treated with ustekinumab from September 2013 to August 2019 was performed to determine perianal fistula response and remission at 6 and 12 months after ustekinumab induction. A systematic review was performed to further establish rates of fistula response and remission with ustekinumab. RESULTS: At 6 months, 48.1% (13/27) patients achieved fistula response with none achieving fistula remission on provider exam, and 59.3% (16/27) achieved patient-reported symptomatic improvement with 3.7% (1/27) achieving symptomatic remission. At 1 year, on provider exam, 55.6% (5/9) had fistula response with none achieving fistula remission, and 100% (9/9) had symptomatic improvement with 22.2% (2/9) achieving symptomatic remission. There were no major safety signals during 1-year follow-up. The systematic review of 25 studies found 44% (92/209) of patients with active perianal fistulas had a clinical response within 6 months of follow-up, and 53.9% (85/152) of patients with 12 months of follow-up achieved clinical response. CONCLUSION: Ustekinumab presents a safe and effective therapy for treatment of pCD. Prospective, randomised trials are needed to further elucidate long-term efficacy of ustekinumab for pCD.

Injury risk-factor differences between two golf swing styles: a biomechanical analysis of the lumbar spine, hip and knee.

The golf swing has been associated with mechanical injury risk factors at many joints. One swing, the Minimalist Golf Swing, was hypothesised to reduce lumbar spine, lead hip, and lead knee ranges of motion and peak net joint moments, while affecting swing performance, compared to golfers' existing swings. Existing and MGS swings of 15 golfers with handicaps ranging from +2 to -20 were compared. During MGS downswing, golfers had 18.3% less lumbar spine transverse plane ROM, 40.7 and 41.8% less lead hip sagittal and frontal plane ROM, and 39.2% less lead knee sagittal plane ROM. MGS reduced lead hip extensor, abductor, and internal rotator moments by 17.8, 19.7 and 43%, while lead knee extensor, abductor, adductor and external rotator moments were reduced by 24.1, 26.6, 37 and 68.8% respectively. With MGS, club approach was 2° shallower, path 4° more in-to-out and speed 2 m/s slower. MGS reduced certain joint ROM and moments that are linked to injury risk factors, while influencing club impact factors with varying effect. Most golf injuries are from overuse, so reduced loads per cycle with MGS may extend the healthy life of joints, and permit golfers to play injury-free for more years.

Sex Difference in Hip Adduction during the Stance Phase of Running: A Swing Phase Problem?

PURPOSE: The purpose of the current study was 1) to evaluate sex differences in peak hip adduction during the late swing and stance phases of running and 2) to determine whether peak hip adduction during late swing is predictive of peak hip adduction during stance. METHODS: A total of 15 female and 16 male heel strike runners ran over ground at a speed of 4 m·s-1. Hip joint kinematics during running were quantified using a 3D motion capture system. Sex differences in peak hip adduction during the late swing and stance phases were compared using independent-samples t-tests. Linear regression analysis was used to determine the relationship between late swing and stance phase hip adduction. RESULTS: Compared with males, females exhibited significantly greater peak hip adduction during both the late swing (8.5° ± 2.6° vs 6.1° ± 2.8°, P = 0.019) and the stance phases of running (13.3° ± 4.2° vs 9.6° ± 3.4°, P = 0.011). Furthermore, late swing peak hip adduction was predictive of subsequent stance phase peak hip adduction (r = 0.63, P < 0.001). CONCLUSION: Sex differences in hip adduction during stance are influenced in part by late swing phase hip adduction. Further studies are needed to identify potential causes of excessive hip adduction during the late swing phase of running.

Role of topical tacrolimus in the management of proctitis, perianal manifestations in Crohn's disease, and chronic pouchitis: a systematic review.

Several published studies have evaluated the safety and effectiveness of oral and intravenous tacrolimus for the management of patients with inflammatory bowel disease (IBD). However, little is known about the effectiveness of topical tacrolimus in this patient population. The aim of this systematic review was to evaluate the current state of literature to evaluate the safety and effectiveness of rectal administration of topical tacrolimus, in the form of suppository, ointment, and/or enema in patients with ulcerative proctitis, perianal Crohn's disease (CD), and chronic refractory pouchitis. Electronic database searches were conducted in international databases since their inception until February 2020. Study subjects were categorized into three groups: topical tacrolimus for patients with proctitis, perianal CD, and chronic refractory pouchitis. The primary end point of this study was the remission rate. Secondary end points were response rate and the incidence of AEs. Eleven studies were included in the final assessment in this systematic review. This provided information from 188 patients. Tacrolimus was administered topically as suppositories, ointment, or enema. Clinical remission was achieved in 57.1%, 57.14%, and 70.0% in patients with proctitis, fistulizing perianal CD, and chronic pouchitis. The most commonly reported side effect was perianal itching and burning. Reversible nephrotoxicity occurred in a single patient. No clear correlation was found between blood levels and clinical outcomes. Topical tacrolimus is effective for a subset of patients with IBD. The adverse effects were minimal and tolerable. Well-designed randomized clinical trials are warranted to establish the appropriate dose and administration method.

Serrated Epithelial Change Is Associated With High Rates of Neoplasia in Ulcerative Colitis Patients: A Case-controlled Study and Systematic Review With Meta-analysis.

BACKGROUND: Patients with long-standing ulcerative colitis (UC) are at an increased risk of colorectal cancer. Risk stratification is important to identify patients who require more frequent endoscopic surveillance. Serrated epithelial change (SEC) found in patients with long-standing colitis may be associated with neoplasia and serve as a marker to stratify patients at higher risk of colorectal cancer (CRC). METHODS: A case-control study was performed to compare the rates of neoplasia between UC patients with SEC and UC patients without SEC who were matched for age, disease duration, and disease extent. Paired tests, conditional logistic regression, and Kaplan-Meier analyses were used to compare groups. A systematic review with meta-analysis was performed, combining our local data with previously published data. RESULTS: This study included 196 UC patients without prior neoplasia, 98 with SEC and 98 without SEC. Ulcerative colitis patients with SEC had a significantly higher rate of synchronous or metachronous neoplasia than UC patients without SEC (26.5% vs 3.1%; P < 0.001). Synchronous or metachronous high-grade dysplasia and CRC were found more frequently in UC patients with SEC than UC patients without SEC (11.2% vs 2.0%; P = 0.02). A meta-analysis was consistent with these findings, showing a higher rate of neoplasia in patients with SEC compared with those without SEC (16.4% vs 3.9%; P < 0.001). CONCLUSION: Serrated epithelial change is associated with a significantly increased risk of synchronous and metachronous neoplasia including high-grade dysplasia and CRC in patients with UC. Histopathological findings of SEC should warrant closer endoscopic surveillance for CRC.

Effect of High Intensity Interval Training on Matrix Metalloproteinases in Women with Breast Cancer Receiving Anthracycline-Based Chemotherapy.

Anthracycline chemotherapy is commonly used to treat breast cancer yet may increase the level of matrix metalloproteinases (MMP) -2 and -9, which increase the risk of atherosclerosis. While exercise has been shown to reduce the level of MMP in patients with diabetes, high intensity interval training (HIIT) has not been utilized to improve level of MMP in women with breast cancer receiving anthracycline chemotherapy. Thirty women were randomized to either 8-week HIIT or control (CON) group. The CON group was offered the HIIT intervention after 8 weeks. MMP-1, -2 -7, -9, tissue inhibitor of MMP (TIMP) -1, and-2 were measured at baseline and post-intervention. Repeated measures ANCOVA and paired t-test were performed to assess changes in MMP and TIMP. Post-intervention, no significant between-group differences were observed for MMP and TIMP. However, within-group decrease in MMP-9 was observed in the HIIT group [104.3(51.9) to 65.2(69.1); P = 0.01]. MMP-9 in the CON group was not significantly changed [115.5(47.2) to 90.4(67.9);]. MMP-2 significantly increased in both the HIIT group [76.6(11.2) to 83.2(13.1); P = 0.007) and the CON group [69.0(8.9) to 77.6(11.1) P = 0.003). It is unclear whether an 8-week HIIT intervention influences MMP-9 in breast cancer patients undergoing anthracycline chemotherapy. Additional investigations are required to understand the exercise-induced changes in MMP-2 and -9 in women undergoing anthracycline chemotherapy.

Hepatic Actinomycosis in a Patient With Retained Common Bile Duct Stent.

Primary hepatic actinomycosis is rare, with less than 100 cases reported in English literature. Most of these cases are cryptogenic. We describe a 35-year-old woman who presented with a retained common bile duct stent for 6 years and found to have a hepatic mass with altered perfusion and enhancement, and minimal degree of washout on enhanced cross-sectional imaging. Fine-needle aspiration revealed presence of filamentous bacteria morphologically consistent with Actinomyces species. This report is a demonstration of a rare instance in which a retained biliary stent led to primary hepatic actinomycosis.

Feasibility of high intensity interval training in patients with breast Cancer undergoing anthracycline chemotherapy: a randomized pilot trial.

BACKGROUND: Anthracycline-based chemotherapy is associated with reduced cardiorespiratory fitness in breast cancer patients. High intensity interval training (HIIT) induces greater benefits on cardiorespiratory fitness than moderate continuous aerobic exercise in patients with heart failure. The study purpose was to determine whether a HIIT intervention is a feasible exercise strategy for breast cancer patients undergoing anthracycline-based chemotherapy. METHODS: Thirty women were randomized to either HIIT or non-exercise control group (CON). Participants performed a maximal cycling fitness test to measure peak power output during maximal oxygen uptake (VO2max). The HIIT group participated in an 8-week HIIT intervention occurring 3 times weekly. Feasibility was calculated by computing (1) the average weekly minutes of HIIT over 8 weeks and (2) the number of sessions attended and multiplied by 100 (percentage of sessions). The intervention was considered feasible if more than 50% of participants completed both an average of 70% of weekly minutes (63/90 min) and attended 70% exercise sessions (17/24 sessions). RESULTS: Participants were 46.9 ± 9.8 (mean ± SD) years old, diagnosed with clinical stage II (30%) or III (63%) breast cancer. The average weekly minutes of exercise completed was 78 ± 5.1 out of 90 min. Twelve of 15 participants met both feasibility criteria, attending 19.2 ± 2.1 out of 24 sessions (82.3%). VO2max was maintained (19.7 ± 8.7 to 19.4 ± 6.6 ml/kg/min) in HIIT group (p = 0.94) while there was a significant decrease in VO2max (18.7 ± 7.1 to 16.1 ± 6.0 ml/kg/min) in CON group from baseline to 8 weeks (p = 0.001). CONCLUSIONS: HIIT is a feasible exercise intervention to maintain VO2max in breast cancer patients receiving anthracycline-based chemotherapy. TRIAL REGISTRATION: The protocol and informed consent were approved by the institutional IRB (HS-12-00227) and registered ( ClinicalTrials.gov NCT02454777; date of registration: May 272,015).

Effects of high-intensity interval training on vascular endothelial function and vascular wall thickness in breast cancer patients receiving anthracycline-based chemotherapy: a randomized pilot study.

PURPOSE: The purpose of this study was to determine the effects of an 8-week high-intensity interval training (HIIT) intervention on vascular endothelial function, measured as brachial artery flow-mediated dilation (baFMD), and vascular wall thickness measured by carotid intima media thickness (cIMT) in breast cancer patients undergoing anthracycline-based chemotherapy. METHODS: Thirty women were randomized to either HIIT or non-exercise control groups (CON). The HIIT group participated in an 8-week HIIT intervention occurring three times per week on a cycle ergometer. The CON group was offered the HIIT intervention after 8 weeks. baFMD was measured from the brachial artery diameter at baseline (D0) and 1 min after cuff deflation (D1); percent change was calculated by measuring brachial artery diameter after cuff deflation relative to the baseline [baFMD = (D1 - D0)/D0 × 100]. The cIMT was obtained from the posterior wall of common carotid artery 10 mm below the carotid bulb. Paired t test and repeated measures ANCOVA were performed to assess changes in baFMD and cIMT. RESULTS: At baseline, the HIIT (n = 15) and CON (n = 15) groups did not differ by age (46.9 ± 9.8 years), BMI (31.0 ± 7.5 kg/m2), and blood pressure (123.4 ± 16.8/72.3.9 ± 5.6 mmHg). Post-exercise, baFMD significantly increased [4.3; 95% confidence interval (CI): (1.5, 7.0), p = 0.005] in HIIT versus CON group. cIMT did not significantly change [0.003, 95% CI - 0.004, 0.009), p = 0.40] in HIIT group, while IMT significantly increased from baseline to post-intervention (0.009, 95% CI 0.004, 0.010, p = 0.003) in CON group. CONCLUSION: This study may suggest that HIIT improved vascular endothelial function and maintained wall thickness in breast cancer patients undergoing anthracycline-based chemotherapy. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02454777.

Standing task difficulty related increase in agonist-agonist and agonist-antagonist common inputs are driven by corticospinal and subcortical inputs respectively.

In standing, coordinated activation of lower extremity muscles can be simplified by common neural inputs to muscles comprising a functional synergy. We examined the effect of task difficulty on common inputs to agonist-agonist (AG-AG) pairs supporting direction specific reciprocal muscle control and agonist-antagonist (AG-ANT) pairs supporting stiffness control. Since excessive stiffness is energetically costly and limits the flexibility of responses to perturbations, compared to AG-ANT, we expected greater AG-AG common inputs and a larger increase with increasing task difficulty. We used coherence analysis to examine common inputs in three frequency ranges which reflect subcortical/spinal (0-5 and 6-15 Hz) and corticospinal inputs (6-15 and 16-40 Hz). Coherence was indeed higher in AG-AG compared to AG-ANT muscles in all three frequency bands, indicating a predilection for functional synergies supporting reciprocal rather than stiffness control. Coherence increased with increasing task difficulty, only in AG-ANT muscles in the low frequency band (0-5 Hz), reflecting subcortical inputs and only in AG-AG group in the high frequency band (16-40 Hz), reflecting corticospinal inputs. Therefore, common neural inputs to both AG-AG and AG-ANT muscles increase with difficulty but are likely driven by different sources of input to spinal alpha motor neurons.