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Predictive value of anal sphincter electromyography for sacral neuromodulation test-phase outcomes.

BACKGROUND: Sacral neuromodulation (SNM) is an established therapy for refractory pelvic organ dysfunction. Anal sphincter electromyography (EMG) is commonly used preoperatively to assess sacral and peripheral nerve integrity. However, the prognostic significance of chronic neurogenic EMG changes for SNM outcomes remains unclear. OBJECTIVE: To evaluate whether chronic neurogenic changes on preoperative anal sphincter EMG predict the outcome of the SNM test phase. METHODS: We retrospectively analysed 62 consecutive patients with bladder and/or bowel dysfunction or pelvic pain who were candidates for SNM treatment and who underwent preoperative anal sphincter EMG. EMG findings were classified as normal or showing chronic neurogenic changes. SNM test-phase success was defined as a ≥50% improvement of symptoms at 24 days. Outcomes were compared between EMG groups. RESULTS: Of the 62 patients (49 women, 13 men), 30 (48%) had normal EMG findings and 32 (52%) showed chronic neurogenic changes. Overall, the SNM test phase was successful in 47 patients (76%). Success rates were similar in patients with normal EMG (72%) and neurogenic EMG changes (79%), with no statistically significant difference (p = 0.878). Sex-stratified analyses revealed no significant association between EMG findings and test-phase success in women or men. CONCLUSIONS: Chronic neurogenic changes on anal sphincter EMG do not predict SNM test-phase outcomes. These findings suggest that abnormal sphincter EMG results should not be used as a standalone criterion to exclude patients from SNM therapy. SIGNIFICANCE: Signs of neurogenic damage on anal sphincter EMG are not an indicator of reduced neuromodulatory capacity or diminished clinical response to SNM.

Humans

The Acute Effects of Blood Flow Restriction on Ankle Muscle Reaction Time and Proprioception in Healthy Individuals.

Blood flow restriction (BFR) induces hypoxic and metabolic stress, which may alter afferent feedback and neuromuscular control. However, its acute effects on ankle sensorimotor function remain unclear. The aim of the study was to investigate the acute effects of lower-limb BFR on multidimensional ankle sensorimotor function in healthy adults. Twenty-four participants (12 females, 12 males) completed two conditions in randomized order and a crossover design: BFR at 60% arterial occlusion pressure (AOP) and a control condition (20 mmHg). All measurements were performed during occlusion. Outcomes included joint position sense (active and passive), kinesthesia, static and dynamic balance, lower-limb muscle activation (surface electromyography), and muscle reaction time during sudden ankle inversion. BFR impaired active joint position sense at 20 degrees of inversion (p = 0.011), with no changes at other angles or in kinesthesia. Static balance deteriorated, with increases in sway area (p = 0.017), sway distance (p = 0.029), and sway velocity (p < 0.001), particularly under eyes-closed single-leg stance. Posterolateral reach distance decreased (p = 0.023), accompanied by reduced lower-limb muscle activation. Tibialis anterior muscle reaction time during 30 degrees of inversion in the ankle neutral position was shortened (p < 0.001), whereas peroneus longus muscle responses were unchanged. Acute lower-limb BFR impairs ankle sensorimotor control by reducing proprioceptive accuracy, balance performance, and muscle activation, while shortening reaction time. These findings suggest caution when applying BFR during tasks that require high postural demands or end-range control. Registration number and date: NCT07307339, 12/26/2025.

Humans

Effect of Motor-Control Exercises on Scapulohumeral and Scapulothoracic Muscle Activations in Athletes With Secondary Subacromial Impingement Syndrome.

CONTEXT: Unbalanced or uncoordinated activity across either the scapulohumeral or the scapulothoracic muscle may impair scapulohumeral rhythm during arm elevation. OBJECTIVE: To compare the effects of progressive resistance exercises (PREs), integrated with and without facilitatory motor-control exercises (MCEs), on scapulohumeral and scapulothoracic myoelectric activities in overhead athletes diagnosed with secondary subacromial impingement syndrome (SAIS). DESIGN: Randomized controlled clinical trial. SETTING: Neuromuscular Rehabilitation Research Center. PATIENTS OR OTHER PARTICIPANTS: Overhead athletes diagnosed with secondary SAIS were assigned randomly to 3 parallel groups: 2 intervention groups and 1 control group. INTERVENTIONS: All groups received contemporary physical therapy modalities every other day for 8 weeks. Intervention groups I and II also completed scapulohumeral and scapulothoracic PREs, integrated, respectively, with and without facilitatory MCEs targeting infraspinatus and lower trapezius muscles. MAIN OUTCOME MEASURES: Scapulohumeral and scapulothoracic myoelectric activities were recorded during scapular arm abduction between 80&#xb0; and 110&#xb0; before and after the prescribed treatment protocols. RESULTS: Scapulohumeral and scapulothoracic PREs reduced the corresponding myoelectric activities during scapular arm abduction within the groups (P &#x2264; .02, partial &#x3b7;2 &#x2265; 0.127). Facilitatory biofeedback-guided exercises integrated into PREs preserved scapulohumeral and scapulothoracic myoelectric activities (P &#x2264; .03), excluding teres minor myoelectric activity (P > .99). CONCLUSIONS: Scapulohumeral and scapulothoracic PREs reduced the corresponding muscle activations during scapular arm abduction in overhead athletes with secondary SAIS. Facilitatory MCEs targeting infraspinatus and lower trapezius muscles, integrated into PREs, preserved scapulohumeral and scapulothoracic muscle activations.

Humans

Acetazolamide to prevent ventilatory drive withdrawal in REM sleep apnoea: a randomised controlled trial.

BACKGROUND: Obstructive sleep apnoea (OSA) pathogenesis during rapid-eye movement (REM) sleep has been linked to dips in ventilatory drive and downstream genioglossus hypotonia. The carbonic anhydrase inhibitor acetazolamide is known to increase ventilatory drive and improve OSA severity. Therefore, we tested the effect of acetazolamide on REM-predominant OSA severity (apnoea hypopnoea index (AHI) and hypoxic burden, co-primary outcomes) and underlying physiological mechanisms (ventilatory drive, ventilation and pharyngeal muscle activity). METHODS: 11 participants with REM-predominant OSA per baseline polysomnography (REM AHI/non-REM AHI&#x2265;2) were allocated to receiving acetazolamide 500&#x2009;mg for three nights (first night at half dose) or placebo according to a randomised, crossover, double-blind design. Detailed physiological polysomnography with recording of diaphragm and genioglossus electromyography was conducted after each intervention, with a 1-week washout in between. RESULTS: As hypothesised, acetazolamide reduced AHI by 35.5% (95% CI 23.1% to 46.3%) and hypoxic burden by 35.9% (95% CI 21.1% to 48.4%) vs placebo (p<0.001), meeting the primary endpoint. Mechanistic analysis in REM revealed that, unexpectedly, acetazolamide did not mitigate dips in ventilatory drive versus placebo (first decile (+0.1 (-1.0 to 1.3) L/min, p=0.8). Rather, acetazolamide reduced collapsibility (increased ventilation at eupneic drive: +1.4 (1.2 to 1.8) L/min) and raised muscle responsiveness (ventilation vs drive slope: +32 (25 to 41) %ventilation/drive, p<0.001; genioglossus versus drive slope: +0.33 (0.13 to 0.54) %max/(L/min), p=0.001). CONCLUSIONS: Acetazolamide modestly improved REM OSA, with meaningful improvements in upper airway physiology, but failed to mitigate the dips in ventilatory drive responsible for REM OSA. TRIAL REGISTRATION NUMBER: NCT05589792.

Humans

Effects of blood flow restriction training combined with plyometric training on lower limb muscle strength and motor unit recruitment in basketball players: An experimental study.

OBJECTIVE: Previous studies have shown that plyometric training (PT) improves neuromuscular function and explosive power but not maximal strength. Blood flow restriction training (BFR) combined with low-intensity resistance training (RT) increases muscle mass and strength. This study investigated the effects of PT, and BFR combined with PT on lower-limb muscle function. METHODS: Twenty elite basketball players were randomly assigned to two groups: PT-alone group (PT, n&#x202f;=&#x202f;10) and BFR combine with PT group (PT-BFR, n&#x202f;=&#x202f;10). All participants underwent bodyweight-based plyometric training three times per week for eight weeks. Peak torque values for hip and knee flexion and extension, as well as root mean square (RMS) values derived from electromyography, were measured before and after the intervention. RESULTS: After the 8-week intervention, both groups showed significant improvements in knee flexion and extension peak torque at 180&#xb0;/s (all p&#x202f;<&#x202f;0.01). Between-group comparisons revealed greater gains in the PT-BFR group for hip extension and flexion at 60&#xb0;/s (p&#x202f;=&#x202f;0.036-0.002; &#x3b7;p2 = 0.225-0.233). RMS of the rectus femoris increased significantly more in the PT-BFR group than in the PT group (right: p&#x2009;=&#x2009;0.004, &#x3b7;p2 = 0.385; left: p&#x2009;=&#x2009;0.020, &#x3b7;p2 = 0.266), whereas no significant changes were observed in the gastrocnemius, tibialis anterior, or biceps femoris (all p&#x2009;>&#x2009;0.05). CMJ height also improved more in the PT-BFR group, with a significant group &#xd7;&#x2009;time interaction (p&#x2009;=&#x2009;0.042, &#x3b7;p2 = 0.210). CONCLUSION: Both training protocols enhanced bilateral lower-limb strength, with notable gains in the non-dominant leg; however, the magnitude did not differ substantially between groups. In contrast, compared with PT alone, BFR combined with PT produced superior enhancements in lower-limb muscle strength and neuromuscular recruitment. These findings suggest that when PT is employed to improve explosive power, it may be effectively combined with BFR to further augment muscular strength.

Humans

Age-related differences in motor unit behaviours and maximal strength: A systematic review and meta-analysis.

Ageing is associated with a decline in strength; however, the neural mechanisms underpinning these changes remain poorly understood. Motor unit discharge rate (MUDR) and recruitment threshold (MURT) regulate the magnitude of motoneuron output through rate coding and orderly recruitment, while discharge rate variability (MUDRV) reflects the steadiness of motoneuron output. Yet, age-related differences in these properties remain inconsistent across the literature. Therefore, this systematic review and meta-analysis quantified age-related differences in motor unit behaviours and their contribution to maximal isometric strength. Electronic databases (Medline, Embase, Scopus, PsycINFO, Ovid Emcare, CENTRAL, and Web of Science) were searched up to May 2025, yielding 1493 records; of these, 48 studies met the inclusion criteria. Standardised mean differences (SMDs) were calculated using random-effects models to compare older and younger adults, and methodological quality was assessed using the AXIS tool. Older adults exhibited markedly lower maximal strength than younger adults (SMD = -1.01; 95% CI -1.22, -0.79). MUDR was lower in older adults across all contraction intensities, with greater reductions at high forces (> 60% maximal voluntary contraction (MVC): SMD =&#x202f;-0.65; 95% CI -0.96, -0.34) compared to low forces (< 30% MVC: SMD = -0.34; 95% CI -0.50, -0.18). Discharge rate variability was greater (SMD = 0.44; 95% CI 0.15, 0.72), whereas recruitment thresholds relative to MVC were lower (SMD = -0.42; 95% CI -0.80, -0.03) in older adults. Collectively, these findings suggest that age-related alterations in motor unit discharge behaviour may contribute, at least in part, to reduced maximal strength in older adults.

Aging

Six weeks of isometric resistance training led to evidence of corticospinal but not reticulospinal adaptation in previously untrained adult males.

The latest hypothesis regarding the source of enhanced neural activation from resistance training is the reticulospinal rather than the corticospinal tract, based on invasive animal and emerging human data. The present study employed a six-week isometric resistance training intervention in a randomized controlled design to address this knowledge gap. Thirty-nine healthy, untrained males (age ~23 y, sustained contraction group n = 13, explosive contraction group n = 9, control group n = 17) underwent neuromuscular and electrophysiological testing and completed all study requirements. Maximal isometric torque (MVC) and rate of torque development (RTD) were measured during a familiarization session as well as before and after the six-week period. Transcranial magnetic stimulation was used to assess motor-evoked potential (MEP) area and silent period duration while subjects contracted to 10% of MVC. Loud sound (120&#xa0;dB) was used to modulate MEP area and reaction time to visual stimuli during the StartReact test. Only the intervention groups demonstrated significant improvements in MVC (27%) and RTD (60%) (both P < 0.01), along with reduced MEP area (-&#xa0;21%) and silent period duration (-&#xa0;23%) (both P < 0.01). The sustained contraction group showed reduced modulation of reaction time and increased MEP suppression due to loud sound. Short-term resistance training seemed to reduce cortical inhibition and corticospinal excitability in both training groups. The study showed conflicting changes in measures purported to evaluate reticulospinal functioning. It is recommended to examine different forms of resistance training and longer training exposure in future.

Humans

Characterizing Submental Neuromuscular Activity of Swallowing Rehabilitation: An Electromyographic Evaluation of Rehabilitative Maneuvers in Healthy Adults.

PURPOSE: The effortful swallow (ES), the Mendelsohn maneuver (MM), and isometric tongue presses (TPs) are widely used swallowing maneuvers/exercises to improve elements of swallowing, such as muscle strength and biomechanics. However, the underlying neuromuscular mechanisms of these exercises remain unclear, potentially limiting our ability to specify treatment targets and improve treatment efficacy. This study aimed to compare submental neuromuscular activation patterns during the ES, MM, TPs, and typical swallows in healthy young and older adults. METHOD: As part of a larger randomized crossover validation study, 60 healthy adults (30 young and 30 older) completed typical swallows and three maneuvers using a wearable submental surface electromyographic (sEMG) system (i-Phagia). Outcome variables included (a) normalized mean sEMG amplitude and (b) time to peak sEMG amplitude. Linear mixed models were used to examine effects of task, age, and sex on both outcomes. RESULTS: Normalized mean amplitude was significantly different across tasks. Post hoc pairwise comparisons confirmed that all three maneuvers produced higher normalized mean sEMG amplitude than typical swallows, with the ES eliciting the highest amplitude across age groups. Time to peak amplitude differed significantly across tasks, with typical swallows requiring the shortest time to reach peak amplitude, followed by the ES, MM, and TP. CONCLUSIONS: The ES required the highest neuromuscular effort with the shortest time to reach peak amplitude, suggesting its potential for targeting submental muscle power. Typical swallows required the least neuromuscular effort with the shortest time to reach peak amplitude, suggesting their potential for training submental muscle speed. The MM and TP may also improve submental muscle strength; however, given their temporal requirements (longer durations), they may be more beneficial for targeting coordination and endurance, though more research in this area is warranted. These findings underscore the importance of task-specific neuromuscular profiling to inform mechanism-based swallowing rehabilitation. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.32948549.

Humans

Acute mild cold exposure with shivering reduces 24 h glucose levels in individuals with type 2 diabetes but not prediabetes.

AIMS/HYPOTHESIS: Repeated cold exposure with shivering has been proposed as a potential strategy to enhance glucose metabolism by increasing energy expenditure and substrate utilisation. However, acute effects/benefits of cold-induced shivering on glucose homeostasis in metabolically compromised individuals are unknown. Here, we aimed to determine whether cold exposure at two different intensities improves 24 h glucose homeostasis in individuals with prediabetes and type 2 diabetes. METHODS: In a randomised crossover trial conducted in the South Limburg/Maastricht region of the Netherlands, men and postmenopausal women with prediabetes (n=12) and stable type 2 diabetes (n=12), aged 40-75 years, body mass index &#x2265;27 and &#x2264;35 kg/m2, non-smoking and sedentary, underwent two whole-body cold exposure sessions using a water-perfused suit. Session order was randomised using an online randomisation tool (randomizer.org); participants were masked to the cold exposure intensity received, but investigators were not. Sessions were designed to elicit ~1.5-fold (mild, 15&#xb0;C) and ~2.5-fold (moderate, 4&#xb0;C) increases in resting metabolic rate (RMR). Continuous glucose monitoring assessed interstitial glucose concentrations over 24 h periods before and after each intervention, with controlled diet and activity. Shivering was confirmed via indirect calorimetry and electromyography. RESULTS: In both study groups and periods, RMR increased significantly vs baseline (p<0.001 for all). In prediabetes, the increase in the final 1 h of cold was 1.53&#xa0;&#xd7;&#xa0;RMR in mild and 1.94&#xa0;&#xd7;&#xa0;RMR in moderate cold. In type 2 diabetes, the increase was 1.57&#xa0;&#xd7;&#xa0;RMR and 2.09&#xa0;&#xd7;&#xa0;RMR in the final 1 h of mild and moderate cold, respectively. In prediabetes, neither mild nor moderate cold exposure altered mean 24 h glucose levels. In contrast, after mild cold exposure the type 2 diabetes group exhibited a significant reduction in mean 24 h glucose levels (-0.6&#xa0;&#xb1;&#xa0;0.5 mmol/l, p=0.003) and fasting glucose (-0.6&#xa0;&#xb1;&#xa0;0.8 mmol/l, p=0.019), as well as an increase in time in normal range (+8.8&#xa0;&#xb1;&#xa0;10.3%, p=0.013) and reduced time in hyperglycaemia (-10.9&#xa0;&#xb1;&#xa0;12.9%, p=0.014). Moderate cold did not significantly affect any of the glucose outcomes in type 2 diabetes. Baseline fasting glucose, age and ALT levels were predictors of the glucose-lowering response, suggesting greater benefits in individuals who have higher baseline glucose levels, are younger and/or have more optimal liver health, i.e. lower ALT. CONCLUSIONS/INTERPRETATION: Acute mild cold exposure with shivering reduced 24 h glucose levels in individuals with type 2 diabetes. No changes were observed in prediabetes. The observed effects appear to depend on baseline metabolic status rather than acute substrate utilisation during cold exposure. These findings support the potential of cold exposure as an adjunct non-pharmacological therapy for type 2 diabetes, although further mechanistic studies and validation in larger cohorts are warranted. TRIAL REGISTRATION: ClinicalTrials.gov NCT05576025 FUNDING: Dutch Organisation for Knowledge and Innovation in Health, Healthcare and Well-being (ZonMw): 09120012010062.

Humans

[Effect of electroacupuncture combined with suspension exercise therapy on lower limb motor function in elderly patients with post-stroke spastic hemiplegia].

OBJECTIVE: To observe the efficacy of electroacupuncture (EA) combined with suspension exercise therapy in elderly patients with post-stroke spastic hemiplegia and its effect on lower limb motor function. METHODS: A total of 120 elderly patients with post-stroke spastic hemiplegia were enrolled. Using a 2&#xd7;2 factorial design, all the patients were assigned to a group A (conventional treatment), a group B (conventional treatment combined with suspension exercise therapy), a group C (conventional treatment combined with EA at Jiaji [EX-B2] and limb acupoints), and a group D(conventional treatment combined with suspension exercise therapy and EA at Jiaji [EX-B2] and limb acupoints), with 30 patients in each group. The main acupoints were bilateral Jiaji (EX-B2) points at the C2-C7, T2-T12, L1-L5, and S1 segments. The adjunct acupoints included Jianyu (LI15), Binao (LI14), Huantiao (GB30), Chengfu (BL36), etc. on the affected side.Continuous wave was applied at a frequency of 100 Hz with a current intensity of 1.5-3.0 mA, and needles were retained for 30 min, once daily for 4 weeks. Before treatment and after 2 and 4 weeks of treatment, the modified Ashworth scale (MAS),Fugl-Meyer assessment (FMA), Berg balance scale (BBS), and Barthel index scores were evaluated in the four groups. Root mean square (RMS) values of surface electromyography (sEMG) of the erector spinae and rectus abdominis muscles on the affected side, as well as balance function indexes, including the mean pressure symmetry index (SI), contact area SI, ellipse area, and displacement distances of the center of pressure in the anteroposterior (AP) and mediolateral (ML) directions, were measured. Clinical efficacy was also compared among the four groups. RESULTS: After 2 and 4 weeks of treatment, MAS scores in all groups were lower than those before treatment (P<0.05), whereas FMA, BBS, and Barthel index scores were higher than those before treatment (P<0.05). After 4 weeks of treatment, MAS scores were lower than those after 2 weeks of treatment (P<0.05), whereas FMA, BBS, and Barthel index scores were higher than those after 2 weeks of treatment (P<0.05) in the four groups. At both 2 and 4 weeks after treatment, group D had lower MAS scores (P<0.05) and higher FMA,BBS, and Barthel index scores (P<0.05) than the other three groups. After 2 and 4 weeks of treatment, RMS values of sEMG of the erector spinae and rectus abdominis muscles on the affected side at all tested angles were higher than those before treatment in all groups (P<0.05), and the values after 4 weeks of treatment were higher than those after 2 weeks of treatment(P<0.05). At both 2 and 4 weeks after treatment, all these indexes in the group D were higher than those in the other three groups (P<0.05). After 2 and 4 weeks of treatment, the mean pressure SI, contact area SI and ellipse area of each group were lower than those before treatment (P<0.05). After 4 weeks of treatment, the mean pressure SI, contact area SI and ellipse area of each group were lower than those after 2 weeks of treatment (P<0.05). After 2 and 4 weeks of treatment, the AP displacement distances of groups A, C and D were lower than those before treatment (P<0.05), and after 4 weeks of treatment, the AP displacement distances of groups A, C and D were lower than those after 2 weeks of treatment (P<0.05);after 2 weeks of treatment, there was no statistically significant difference in AP displacement distance in the group B compared with before treatment (P>0.05), and after 4 weeks of treatment, the AP displacement distance of group B was lower than that before treatment (P<0.05). After 2 weeks of treatment, there was no statistically significant difference in ML displacement distance in group A compared with before treatment (P>0.05); after 4 weeks of treatment, the ML displacement distance of group A was lower than that before treatment (P<0.05). After 2 and 4 weeks of treatment, there was no statistically significant difference in ML displacement distance in the group B compared with that before treatment (P>0.05).After 2 and 4 weeks of treatment, the ML displacement distances of groups C and D were lower than those before treatment(P<0.05), and after 4 weeks of treatment, the ML displacement distances of groups C and D were lower than those after 2 weeks of treatment (P<0.05). At both 2 and 4 weeks after treatment, mean pressure SI, contact area SI, ellipse area, and AP and ML displacement distances in the group D were lower than those in the other three groups (P<0.05). Factorial analysis of variance showed that EA had the strongest main effect on FMA score (F=6.243, P<0.05), suspension exercise therapy had the strongest main effect on BBS score (F=6.292, P<0.05), and the interaction effect was most significant for MAS score (F=5.941, P<0.05), indicating that the combined therapy produced a greater synergistic effect on reducing muscle tone than on the other outcome measures. The total effective rate in the group D was 93.3% (28/30), which was higher than those in the group A (53.3% [16/30]), group B (56.7% [17/30]), and group C (66.7% [20/30], P<0.05). CONCLUSION: EA combined with suspension exercise therapy could effectively promote the recovery of lower limb function in elderly patients with post-stroke spastic hemiplegia, improve motor and balance functions, and enhance activities of daily living.

Humans