Validation of a Single-Session Protocol to Determine the Load-Velocity Profile and One-Repetition Maximum for the Back Squat Exercise.

ABSTRACT: Gomes, M, Fitas, A, Santos, P, Pezarat-Correia, P, and Mendonca, GV. Validation of a single session protocol to determine the load-velocity profile and one-repetition maximum for the back squat exercise. J Strength Cond Res 38(6): 1013-1018, 2024-We investigated whether a single session of absolute incremental loading is valid to obtain the individual load-velocity profile (LVP) and 1 repetition maximum (1RM) for the free-weight parallel back squat. Twenty strength-trained male subjects completed 3 testing sessions, including a baseline 1RM session and 2 LVP sessions (LVP rel based on incremental relative loads and LVP abs based on absolute load increments until 1RM). The 1RM load was compared between the baseline and LVP abs . The load at zero velocity (load-axis intercept [L 0 ]), maximal velocity capacity (velocity-axis intercept [V 0 ]), slope, and area under the load-velocity relationship line (A line ) were compared between the LVP rel and LVP abs using equivalence testing through 2 one-sided t -tests. Measurement accuracy was calculated using the absolute percent error. The 1RM measured at baseline and LVP abs was equivalent and presented a low absolute percent error (1.2%). The following LVP parameters were equivalent between LVP rel and LVP abs : 1RM, L 0 , and A line because the mean difference between sessions was close to zero and the Bland-Altman limits of agreement (1RM:5.3 kg; L 0 :6.8 kg; A line : 9.5 kg·m -1 ·s -1 ) were contained within the a priori defined ± equivalent margins (5% for 1RM and L 0 and 10% for A line ). The aforementioned variables presented a low absolute percent error. However, slope and V 0 were not equivalent between sessions. In conclusion, a single session of absolute incremental loading is a valid approach to obtain the L 0 and A line of the individual LVP and 1RM, and can be used to efficiently track the magnitude of neuromuscular adaptations throughout the training cycles for the free-weight back squat.

Prediction of One Repetition Maximum in Free-Weight Back Squat Using a Mixed Approach: The Combination of the Individual Load-Velocity Profile and Generalized Equations.

ABSTRACT: Fitas, A, Santos, P, Gomes, M, Pezarat-Correia, P, Schoenfeld, BJ, and Mendonca, GV. Prediction of one repetition maximum in free-weight back squat using a mixed approach: the combination of the individual load-velocity profile and generalized equations. J Strength Cond Res 38(2): 228-235, 2024-We aimed to develop a mixed methods approach for 1 repetition maximum (1RM) prediction based on the development of generalized equations and the individual load-velocity profile (LVP), and to explore the validity of such equations for 1RM prediction. Fifty-seven young men volunteered to participate. The submaximal load-velocity relationship was obtained for the free-weight parallel back squat. The estimated load at 0 velocity (LD0) was used as a single predictor, and in combination with the slope of the individual LVP, to develop equations predictive of 1RM. Prediction accuracy was determined through the mean absolute percent error and Bland-Altman plots. LD0 was predictive of 1RM ( p < 0.0001), explaining 70.2% of its variance. Adding the slope of the LVP to the model increased the prediction power of 1RM to 84.4% ( p < 0.0001). The absolute percent error between actual and predicted 1RM was lower for the predictions combining LD0 and slope (6.9 vs. 9.6%). The mean difference between actual and estimated 1RM was nearly zero and showed heteroscedasticity for the LD0 model, but not for the combined model. The limits of agreement error were of 31.9 and 23.5 kg for LD0 and LD0 combined with slope, respectively. In conclusion, the slope of the individual LVP adds predictive value to LD0 in 1RM estimation on a group level and avoids error trends in the estimation of 1RM over the entire spectrum of muscle strength. However, the use of mixed methods does not reach acceptable accuracy for 1RM prediction of the free-weight back squat on an individual basis.

Predictive Equations to Estimate Relative Load Based on Movement Velocity in Males and Females: Accuracy of Estimation for the Smith Machine Concentric Back Squat.

ABSTRACT: Mendonca, GV, Fitas, A, Santos, P, Gomes, M, and Pezarat-Correia, P. Predictive equations to estimate relative load based on movement velocity in males and females: accuracy of estimation for the Smith machine concentric back squat. J Strength Cond Res 37(8): 1559-1565, 2023-We sought to determine the validity of using the Smith machine bar velocity to estimate relative load during the concentric back squat performed by adult male and female subjects. Thirty-two subjects (16 men: 23.3 ± 3.8 and 16 women: 26.1 ± 2.7 years) were included. The load-velocity relationship was extracted for all subjects individually. Mean concentric velocity (MCV), combined with sex, was used to develop equations predictive of relative load (% one repetition maximum [1RM]). Prediction accuracy was determined with the mean absolute percent error and Bland-Altman plots. Relative strength was similar between the sexes. However, male subjects exhibited faster concentric MCV at 1RM ( p < 0.05). Mean concentric velocity and the sex-by-MCV interaction were both significant predictors of %1RM ( p < 0.0001), explaining 89% of its variance. The absolute error was similar between the sexes (men: 9.4 ± 10.0; women: 8.4 ± 10.5, p > 0.05). The mean difference between actual and predicted %1RM in Bland-Altman analysis was nearly zero in both sexes and showed no heteroscedasticity. The limits of agreement in both men and women were of approximately ±15%. Taken together, it can be concluded that sex should be taken into consideration when aiming at accurate prescription of relative load based on movement velocity. Moreover, predicting relative load from MCV and sex provides an error of approximately 10% in assessments of relative load in groups of persons. Finally, when used for individual estimations, these equations may implicate a considerable deviation from the actual relative load, and this may limit their applicability to training conditions in which extreme accuracy is required (i.e., more advanced lifters and athletes).

Choroidal neovascularization secondary to pathological myopia-macular Bruch membrane defects as prognostic factor to anti-VEGF treatment.

PURPOSE: To evaluate the prevalence and visual outcomes of macular Bruch membrane (BM) defects in patients treated with anti-vascular endothelial growth factors (VEGF) for choroidal neovascularization secondary to pathological myopia (mCNV). METHODS: Single-center retrospective observational case series of 68 eyes from 62 patients with mCNV treated with one anti-VEGF injection followed by a pro re nata (1 + PRN) regimen. A minimum follow-up of 6 months was defined. Chorioretinal atrophy was assessed by fundus examination, fluorescein angiography, and SD-OCT. RESULTS: Median follow-up was 28.5 (range 6-89) months with a median number of 5 anti-VEGF injections. At baseline, 27.9% of eyes had macular BM defects increasing to 36.8% during follow-up (p<0.001). Eyes without macular BM defects at the baseline had higher BCVA at the last observation than patients with BM defects (p=0.003). An increase of 5 or more ETDRS letters was more frequent in eyes without BM defects (p=0.001). At the end of follow-up, mCNV-related macular atrophy was present in 44.1%; out of which, 83.3% presented macular BM defects (p<0.001). Eyes with mCNV-related macular atrophy without BM defects had a significant increase of best-corrected visual acuity compared with eyes with mCNV-related macular atrophy and BM defect (p=0.002). CONCLUSIONS: Macular Bruch membrane defects are often seen in mCNV and have a significant impact in visual acuity and prognosis. Eyes with macular BM defects have a poorer response and worse visual outcomes after anti-VEGF therapy.

Sex differences in soleus muscle H-reflex and V-wave excitability.

NEW FINDINGS: What is the central question of this study? How do H-reflex and V-wave excitability compare between men and women engaging in similar levels of physical activity?  What is the main finding and its importance? H-reflex excitability is lower in women than in men because of their greater level of antagonist co-activation during sustained plantar flexion isometric exercise. In addition, supraspinal drive is similar between men and women independently of their differences in H-reflex excitability and antagonist muscle co-activation. ABSTRACT: We compared H-reflex and V-wave excitability between men and women engaging in similar levels of physical activity. We also explored whether differences in antagonist muscle co-activation between sexes might partially explain sexual dimorphism in the excitability of the H-reflex and V-wave. Fifty-seven young participants were included (29 men: 21.7 ± 2.3 years; 28 women: 22.4 ± 3.3 years). Soleus M- and H-recruitment curves were constructed on a tonic background muscle activation. V-waves were elicited during maximal voluntary contraction (MVC). Besides being stronger than women, men achieved greater Hmax /Mmax values and presented a steeper slope of the ascending limb of the H-reflex recruitment curve (P < 0.05). The current intensity required to elicit Hmax was lower for men (P < 0.05). The co-activation of the tibialis anterior muscle during the sustained plantar flexions was greater in women (ratio between tibialis and soleus normalized EMG: 20.5 vs. 8.3%, P < 0.05). Covariance analysis showed that sexual dimorphism in H-reflex excitability was dissipated when controlling for antagonist co-activation. V-wave normalized amplitude was similar between sexes even after controlling for the effects of Hmax /Mmax and antagonist co-activation as covariates. Thus, women exhibit lower H-reflex excitability than men and this is dependent on their higher level of antagonist muscle co-activation. While sex differences in antagonist co-activation persist during MVCs, this is not the case for V-wave normalized amplitude. Thus, although the efficacy of the transmission between Ia afferent fibres to α-motoneurons is lower in women because of a greater level of antagonist co-activation, our findings are consistent with similar supraspinal drive between sexes.

Mortality After Paclitaxel-Coated Device Use in Patients With Chronic Limb-Threatening Ischemia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

PURPOSE: To report the risk of all-cause mortality after treatment with paclitaxel-coated devices vs uncoated controls in patients with chronic limb-threatening ischemia (CLTI). MATERIALS AND METHODS: A search of the PubMed, Embase, Cochrane, CINAHL, DARE, and PROSPERO databases was made on 5 November 2019 to identify randomized controlled trials (RCT) using intention-to-treat analysis to compare a paclitaxel-coated device to an uncoated device in PAD patients having clinical follow-up of at least 6 months. Half of the study population had to have CLTI or extractable data on the CLTI subgroup if <50%. The search identified 11 trials having 1450 patients randomized to a paclitaxel-coated device (n=866) or an uncoated control (n=584). There were 1367 (94.3%) patients with CLTI (range 10-429). The single endpoint was all-cause mortality, which was analyzed by pooling the mortality data in a DerSimonian and Laird random effects model. Summary statistics are expressed as relative risk ratios (RR) with a 95% confidence interval (CI). RESULTS: The mean follow-up was 25.6 months (range 6-60); 10 of 11 studies reported a minimum 12-month follow-up. There were 161 (18.6%) deaths among 866 subjects in the paclitaxel device group and 116 deaths among 584 (19.9%) subjects in the non-coated control group (RR 0.93, 95% CI 0.78 to 1.12, p=0.45). CONCLUSION: There was no observed difference in short- to midterm mortality among a pooled patient population of predominately CLTI patients treated with paclitaxel-coated balloons or stents compared with uncoated controls.

Kounis Syndrome after Angioplasty of the Superficial Femoral Artery with Paclitaxel-Coated Balloon.

Drug-coated balloons are used widely as a form of endovascular treatment for peripheral arterial disease, to improve patency by reducing neointimal hyperplasia and restenosis. We present a rare case of acute coronary syndrome secondary to anaphylaxis after inflation of a paclitaxel-coated balloon used to treat a recurrent superficial femoral artery stenosis.

An Original Bailout Solution for Renal Artery Dissection after Fenestrated/Branched EVAR.

BACKGROUND: Renal artery (RA) dissection may occur during endovascular treatment of thoracoabdominal aneurysms. The aim of this paper is to report the use of kissing coronary stents in the renal bifurcation as a bailout solution for dissection after fenestraded/branched endovascular aortic repair (F/B-EVAR). METHODS/RESULTS: A 73-year-old male with an asymptomatic Crawford type 4 thoracoabdominal aneurysm and a concomitant right common iliac artery aneurysm was proposed for endovascular repair, consisting of thoracic endovascular aortic repair plus custom-made device F/B-EVAR, followed by staged bifurcated EVAR plus right-sided IBD. In the control angiogram of the first procedure, a distal occlusion of the left renal artery was observed and attributed to iatrogenic dissection. The 6F sheath was reintroduced and the two main branches of the RA were catheterized with 0.014 wires. Then, two coronary drug-eluting stents were used for a kissing stenting technique with good angiographic and clinical results. As planned, one week later the patient underwent an uneventful second stage procedure. Follow-up CTA at 1 year showed normal patency of the renal stents as well as aneurysm shrinking and no signs of endoleak. CONCLUSIONS: In the reported case, the use of coronary stents was a safe and long-lasting solution to rescue an iatrogenic renal artery dissection during F/B-EVAR.

Effect of Donepezil, Tacrine, Galantamine and Rivastigmine on Acetylcholinesterase Inhibition in Dugesia tigrina.

Dugesia tigrina is a non-parasitic platyhelminth, which has been recently utilized in pharmacological models, regarding the nervous system, as it presents a wide sensitivity to drugs. Our trials aimed to propose a model for an in vivo screening of substances with inhibitory activity of the enzyme acetylcholinesterase. Trials were performed with four drugs commercialized in Brazil: donepezil, tacrine, galantamine and rivastigmine, utilized in the control of Alzheimer's disease, to inhibit the activity of acetylcholinesterase. We tested five concentrations of the drugs, with an exposure of 24 h, and the mortality and the inhibition of acetylcholinesterase planarian seizure-like activity (pSLA) and planarian locomotor velocity (pLMV) were measured. Galantamine showed high anticholinesterasic activity when compared to the other drugs, with a reduction of 0.05 µmol·min(-1) and 63% of convulsant activity, presenting screw-like movement and hypokinesia, with pLMV of 65 crossed lines during 5 min. Our results showed for the first time the anticholinesterasic and convulsant effect, in addition to the decrease in locomotion induced by those drugs in a model of invertebrates. The experimental model proposed is simple and low cost and could be utilized in the screening of substances with anticholinesterasic action.

Dynamically predicting comprehension difficulties through physiological data and intelligent wearables.

Comprehending digital content written in natural language online is vital for many aspects of life, including learning, professional tasks, and decision-making. However, facing comprehension difficulties can have negative consequences for learning outcomes, critical thinking skills, decision-making, error rate, and productivity. This paper introduces an innovative approach to predict comprehension difficulties at the local content level (e.g., paragraphs). Using affordable wearable devices, we acquire physiological responses non-intrusively from the autonomous nervous system, specifically pulse rate variability, and electrodermal activity. Additionally, we integrate data from a cost-effective eye-tracker. Our machine learning algorithms identify 'hotspots' within the content and regions corresponding to a high cognitive load. These hotspots represent real-time predictors of comprehension difficulties. By integrating physiological data with contextual information (such as the levels of experience of individuals), our approach achieves an accuracy of 72.11% ± 2.21, a precision of 0.77, a recall of 0.70, and an f1 score of 0.73. This study opens possibilities for developing intelligent, cognitive-aware interfaces. Such interfaces can provide immediate contextual support, mitigating comprehension challenges within content. Whether through translation, content generation, or content summarization using available Large Language Models, this approach has the potential to enhance language comprehension.

Effects of auriculotherapy on muscle fatigue: A randomized crossover trial.

OBJECTIVE: This study aimed investigate the effect of auriculotherapy on exercise-induced muscle fatigue, isometric torque production, and surface electromyographic activity (EMG). METHODS: Design: Randomized Crossover Trial. The sample consisted of 18 males' volunteers who exercised at least twice a week. THE SAMPLE WAS RANDOMLY ASSIGNED TO TWO GROUPS: Placebo Group (n = 9) and Treated Group (n = 9), and after seven days, the groups were crossed. The data analysis included 18 participants in each group. MAIN OUTCOME MEASURE: The muscle fatigue index, force production rate, and EMG of the quadriceps were used for evaluation. The evaluation moments included baseline pre-fatigue, baseline post-fatigue, 48 h post-intervention pre-fatigue, and 48 h post-intervention post-fatigue. Mixed two-way test ANOVA was used to compare times and groups. RESULTS: The fatigue index for peak torque and work showed no significant effect on time, groups, or interaction (p > 0.05). However, for isometric torque, force production rate, and EMG median frequency and average, the results indicate a positive change in values over time (p < 0.05) (with little practical relevance), with no differences observed between the groups or interaction (p > 0.05). CONCLUSIONS: In conclusion, auriculotherapy had no effect on exercise-induced muscle fatigue, isometric torque production, and surface electromyographic activity.

Personalizing health care: feasibility and future implications.

Considerable variety in how patients respond to treatments, driven by differences in their geno- and/ or phenotypes, calls for a more tailored approach. This is already happening, and will accelerate with developments in personalized medicine. However, its promise has not always translated into improvements in patient care due to the complexities involved. There are also concerns that advice for tests has been reversed, current tests can be costly, there is fragmentation of funding of care, and companies may seek high prices for new targeted drugs. There is a need to integrate current knowledge from a payer's perspective to provide future guidance. Multiple findings including general considerations; influence of pharmacogenomics on response and toxicity of drug therapies; value of biomarker tests; limitations and costs of tests; and potentially high acquisition costs of new targeted therapies help to give guidance on potential ways forward for all stakeholder groups. Overall, personalized medicine has the potential to revolutionize care. However, current challenges and concerns need to be addressed to enhance its uptake and funding to benefit patients.

Squamous Cell Carcinoma of the Conjunctiva in a Patient With Previous Squamous Cell Carcinoma of the Lower Lip.

Squamous cell carcinoma (SCC) of the conjunctiva is a rare malignancy that is part of the spectrum of ocular surface squamous neoplasia (OSSN). Numerous non-modifiable and modifiable risk factors, such as male sex, age, cigarette smoking, and immunosuppression, have been identified. Any lesion of the conjunctiva requires a differential diagnosis between benign and malignant diseases, and all suspicious lesions should be biopsied. We present a case of SCC of the conjunctiva in a former smoker with multiple risk factors, including a previous SCC of the lower lip. Metastatic tumors rarely occur in the conjunctiva, but due to our patient's medical history, the exclusion of metastasis from the previous primary tumor was performed through whole-body imaging restaging.  The patient underwent a no-touch wide resection, followed by adjuvant topical chemotherapy with 5-fluorouracil (5-FU). After finishing treatment, the patient continues to attend regular ophthalmology and oncology appointments. Increasing population awareness of modifiable risk factors for OSSN is essential. Misdiagnosis can lead to a loss of time in treatment and progression of the disease.

Intrastromal Corneal Ring Segment Implantation in a Patient with the Bowman Layer Inlay Transplantation for Keratoconus.

Keratoconus (KC) is a bilateral ectatic corneal disease which results in changes in the corneal architecture and can lead to severe visual impairment. Treatment options depend on the stage of the disease, and they aim either at improving vision or arrest progression. The Bowman layer transplantation (BLT) is a recent surgical option in patients with KC and may postpone corneal transplantation in some patients. We present a case of a 22-year-old patient with a 10-year follow-up history of progressing KC. A first attempt for an intracorneal ring segment (ICRS) implantation when he was 13 years old was unsuccessful due to a superficially implanted segment. At that time, collagen cross-linking was unavailable, and his young age raised concerns about performing a penetrating keratoplasty/lamellar keratoplasty. A BLT was performed with further ICRS implantation with relative disease stability and visual improvement. ICRS implantation in KC patients with BLT has not previously been described in literature and can be an option in selected patients.

Case Report: Alternaria alternata keratitis.

Background: Alternaria spp are ubiquitous pigmented filamentous fungi that can cause opportunistic human infections. These molds can be found in healthy individuals and the most frequently observed clinical manifestations are skin infections, ocular mycosis, rhinosinusitis, among others. Immunosuppression (both local and systemic) as well as contact or trauma with contaminated matter are important risk and predisposing factors for ocular mycosis. Accurate diagnosis with microscopy and culture is crucial since infections by filamentous fungi are sight-threatening, and clinically indistinguishable from bacterial disease. In general terms, conventional antifungal drugs are effective. Case Presentation: We report a case of Alternaria alternata keratitis after ocular trauma with biological material in a 44-year-old man's functional single eye, which had a good clinical and functional evolution after topical therapy with voriconazole. Conclusion: This case accounts the importance of thinking about other etiological diagnoses in infectious keratitis refractory to the established therapy and with a history of trauma with biological material.

Descemet Stripping Without Endothelial Keratoplasty in Early-Stage Central Fuchs Endothelial Dystrophy: Long-term Results.

PURPOSE: The purpose of this study was to report long-term results of Descemet stripping without endothelial keratoplasty (DWEK) associated with phacoemulsification in patients with early-stage central Fuchs endothelial corneal dystrophy. METHODS: This is a retrospective study, including all patients submitted to DWEK associated with cataract surgery with a minimum follow-up of 24 months. Included patients had central confluent guttae confirmed with specular microscopy, a clear peripheral endothelium (with a peripheral endothelial count >1500 cells/mm 2 ), and a central pachymetry <600 µm. The main end points were the presence of a clear cornea and time that was needed to achieve transparency, best-corrected visual acuity in logMAR, endothelial central cell count (ECC), and central pachymetry. RESULTS: A total of 22 eyes were included with a mean follow-up of 40.8 ± 10.5 months. At baseline, mean central pachymetry was 536 ± 34 mm and 6 eyes had countable ECC (mean 1138 ± 190 cells/mm 2 ). Twenty eyes (90.9%) achieved good corneal transparency 3.2 ± 1.1 months after surgery. There was a significant improvement in logMAR best-corrected visual acuity compared with baseline (0.13 ± 0.10 vs. 0.48 ± 0.24, respectively, P < 0.001). Endothelial central repopulation was observed in all successful cases. Twelve months after DWEK, ECC was 1449 ± 344 cells/mm 2 and 1393 ± 450 cells/mm 2 at the end of follow-up, without a significant decrease between this period ( P = 0.081). Only 2 eyes (9.1%) did not achieve corneal transparency and were submitted to an endothelial keratoplasty. CONCLUSIONS: According to our results, DWEK is a safe and effective procedure in selected cases of early-stage central Fuchs endothelial corneal dystrophy. This seems to be a promising technique, delaying or avoiding endothelial transplantation.

Changes in lung function in adolescents with substance use disorders: an exploratory study.

OBJECTIVE: To compare lung function between adolescents with and without substance use disorder (SUD). METHODS: This was an observational, cross-sectional exploratory study. The sample consisted of 16 adolescents with SUD and 24 age-matched healthy controls. The adolescents in the clinical group were recruited from a psychiatric inpatient unit for detoxification and rehabilitation; their primary diagnosis was SUD related to marijuana, cocaine, or polysubstance use. Questionnaires and pulmonary function tests were applied for clinical evaluation. RESULTS: We found that FVC, FEV1, and their percentages of the predicted values were significantly lower in the adolescents with SUD than in those without. Those differences remained significant after adjustment for BMI and the effects of high levels of physical activity. The largest effect size (Cohen's d = 1.82) was found for FVC as a percentage of the predicted value (FVC%), which was, on average, 17.95% lower in the SUD group. In addition, the years of regular use of smoked substances (tobacco, marijuana, and crack cocaine) correlated negatively with the FVC%. CONCLUSIONS: This exploratory study is innovative in that it demonstrates the early consequences of smoked substance use for the lung health of adolescents with SUD.

Sure-thing vs. probabilistic charitable giving: Experimental evidence on the role of individual differences in risky and ambiguous charitable decision-making.

Charities differ, among other things, alongside the likelihood that their interventions succeed and produce the desired outcomes and alongside the extent that such likelihood can even be articulated numerically. In this paper, we investigate what best explains charitable giving behaviour regarding charities that have interventions that will succeed with a quantifiable and high probability (sure-thing charities) and charities that have interventions that only have a small and hard to quantify probability of bringing about the desired end (probabilistic charities). We study individual differences in risk/ambiguity attitudes, empathy, numeracy, optimism, and donor type (warm glow vs. pure altruistic donor type) as potential predictors of this choice. We conduct a money incentivised, pre-registered experiment on Prolific on a representative UK sample (n = 1,506) to investigate participant choices (i) between these two types of charities and (ii) about one randomly selected charity. Overall, we find little to no evidence that individual differences predict choices regarding decisions about sure-thing and probabilistic charities, with the exception that a purely altruistic donor type predicts donations to probabilistic charities when participants were presented with a randomly selected charity in (ii). Conducting exploratory equivalence tests, we find that the data provide robust evidence in favour of the absence of an effect (or a negligibly small effect) where we fail to reject the null. This is corroborated by exploratory Bayesian analyses. We take this paper to be contributing to the literature on charitable giving via this comprehensive null-result in pursuit of contributing to a cumulative science.

Neuromuscular Impact of Acute Hypertrophic Resistance Loading with And Without Blood-Flow Restriction.

Exploring acute neuromuscular fatigue induced by different modalities of resistance exercise would help understand the adaptation subsequent to specific training programs. Therefore, we investigated the acute impact of high-intensity and low-intensity blood flow-restricted resistance exercise on the development of explosive torque throughout the torque-time curve. Seventeen healthy, young participants were included in a randomized, counterbalanced within-subjects design study, in which participants underwent two experimental conditions, separated by a 1-wk period. Low-intensity blood-flow restricted exercise and high-intensity resistance exercise were performed using dynamic elbow flexion at 20 and 75% of 1 repetition maximum, respectively. Maximal voluntary contraction (MVC) and the sequential rate of torque development (absolute and relative) were measured before and after exercise. Both protocols elicited a similar decrement in MVC (~ 25%) and in the peak rate of torque development after exercise (~ 45%). The absolute rate of torque development (0-50 and 50-100 ms) was also reduced (p<0.05) similarly between conditions. After normalizing torque values to MVC, this was only sustained for the rate of torque development 0-50ms (p<0.05). We found that both exercise protocols induced similar acute attenuation of the absolute rate of torque development up to the first 100 ms of MVC. We also demonstrated that the reduction in the rate of torque development between 50-100ms (in both protocols) was largely explained by an acute deficit in muscle strength post-exercise. Conversely, the impact of each protocol on the first 50ms of muscle torque did not depend on lower levels of muscle strength after exercise.

Effects of surgical masks on the responses to constant work-rate cycling performed at different intensity domains.

We aimed at examining the impact of wearing surgical face masks on exercise performance. Thirty-two healthy adults (16 males and 16 females) completed a graded exercise test to measure peak oxygen uptake (VO2peak ) and the ventilatory threshold (VT). Then, on separate days, all participants performed resting and standardized protocols (moderate intensity: 25% infra-VT; severe intensity: 25% supra-VT) on two different conditions (with and without a surgical mask). The use of masks reduced both VO2 and minute ventilation during moderate and severe exercise (p < 0.0001), and this effect was particularly pronounced during severe exercise. Time to exhaustion was also shortened by ~10% on the face mask condition (p = 0.014). In contrast, neither heart rate nor the respiratory exchange ratio was affected by masking. The submaximal VO2 was similar between the two epochs of analysis obtained during moderate cycling (i.e. 3-6 min vs. 7-10 min) and this occurred similarly between conditions. In conclusion, the impact of the surgical masks on exercise capacity is particularly pronounced during severe exercise performed at constant work rate. Ultimately, this may implicate a considerable impairment of structured or even unstructured strenuous physical activity. Clinical Trials registration number: NCT04963049.