Physical Activity Effects on Muscle Fatigue in Sport in Active Adults with Long COVID-19: An Observational Study.

Long COVID-19-related changes in physiology includes alterations in performing muscle work as fatigue. Data available do not allow us to define the usefulness of physical activity to attenuate long COVID-19 functional modifications. The present observational study investigates the effects of physical activity on the perception of fatigue, maximum power output, sleep, and cognitive modifications in subjects affected by long COVID-19, distinguishing between active and sedentary subjects. The data demonstrated the following: the perception of fatigue 1 year after the end of virus positivity was significantly reduced with respect to that observed after 6 months by more than 50% more in active subjects compared to sedentary ones; 6 months after the end of virus positivity, the force developed by active subjects was reduced (RM factor: p < 0.001, η2p = 0.527, post hoc: p < 0.001), but the reduction was more pronounced in sedentary ones (mean difference = 38.499 W); poor sleep quality and mild cognitive impairment were assessed in both active and sedentary subjects. In conclusion, the study suggests that the long COVID-19 fatigue was lower in active subjects respect to sedentary ones. A comparative analysis performed due to the overlap of functional alterations between long COVID-19 and ME/CFS showed that in a small percentage of the enrolled subjects (8%), the symptomatology reflected that of ME/CFS and was independent of the individual physical capacities.

Effects Of An Early Rehabilitation Program In COVID-19 Patients Weaned From Non-Invasive Mechanical Ventilation: The Experience Of A Respiratory Subintensive Unit

Background: The purpose of the study was to verify the variation of some physiopathological-respiratory parameters, physical performance indicators and the ability to carry out activities of daily living in a group of patients suffering from respiratory failure secondary to SARS-CoV2 pneumonia newly weaned from non-invasive ventilation. Method(s): This study was conducted on 20 patients with SARS-CoV2 pneumonia admitted in a COVID-19 subintensive respiratory unit of Cotugno Hospital in Naples, who have just been weaned from non-invasive mechanical ventilation. The experimental group underwent an early rehabilitation lasting 7 days in addition to a specific medical therapy. Result(s): The intragroup comparison showed in the rehabilitation group an improvement in PaO2/FiO2 ratio, respiratory function physical performance measured by "handgrip test" and by "sit to stand test" (number of repetitions, dyspnoea measured by Borg modified scale, muscular fatigue measured by Borg) and in Barthel Index score. The control group showed an improvement only in PaO2/FiO2 ratio and Bathel Index Score. Conclusion(s): An early rehabilitation program initiated immediately after weaning from NIV is effective in improving gas exchanges, physical performance and daily life activities in a group of patients with respiratory failure secondary to SARS-CoV2 pneumonia.

COVID-19 Malaysia Overview: Evaluate Driving Awkward Posture and Muscle Fatigue Through RULA and Electromyography (EMG) Analysis on Health Problem Among Older Taxi Drivers

Driving taxis is one of the alternative jobs older people took up during the COVID-19 pandemic. This study evaluated driving posture and muscle fatigue among older taxis drivers in Malaysia during COVID-19 using Rapid Limb Assessment and Electromyography. The Rapid Upper Limb Assessment questions were used to assess awkward driving posture and Electromyography to measure muscular fatigue. RULA analysis body score at value score 7 (23.5%)- required change immediately and value score 5/6 (61.9%) - required investigation and change soon. There is a significant decrease in energy (p<0.05) on EMG analysis. Ergonomic education on driving posture may improve the lifestyle and well-being of older Malaysian taxis driver. [ FROM AUTHOR]

SEROPOSITIVE MYASTHENIA GRAVIS AS THE CAUSE OF MULTIPLE FAILED EXTUBATIONS AND A PROLONGED ICU STAY FOR COVID-19 PNEUMONIA: A CASE REPORT AND BRIEF LITERATURE REVIEW

SESSION TITLE: Autoimmune Disorders: Both Primary and Secondary SESSION TYPE: Rapid Fire Case Reports PRESENTED ON: 10/18/2022 10:15 am - 11:10 am INTRODUCTION: Neurologic sequelae of COVID infection appear to be common. The infection may present with neurologic symptoms, unmask neurologic disease, or worsen established disease. Myasthenia gravis (MG) is an autoimmune neuromuscular disease (NMD) that does not appear to be a usual COVID sequela. We present an elderly veteran with COVID pneumonia who struggled to wean from mechanical ventilation (MV) secondary to neuromuscular weakness. He was ultimately diagnosed with seropositive MG. CASE PRESENTATION: A 79 year old male with a history of prior COVID infection complicated by need for mechanical ventilation (MV) complained of progressive cough and shortness of breath. He was admitted for treatment of community-acquired pneumonia. On hospital day 8, he developed respiratory failure, was intubated, and was transferred to the intensive care unit (ICU). He was diagnosed with COVID a second time. After antibiotics and supportive treatment, he successfully completed a spontaneous breathing trial and was extubated. Within 24 hours, he developed hypercapnia, necessitating reintubation. Given his need for repeat intubations, we ordered myositis titers and MG autoantibodies. After a fourth failed extubation, a tracheostomy was placed. On hospital day 32, his acetylcholine receptor binding antibody returned positive at 30.0, suggesting seropositive MG. His MG composite score was 11 (for ptosis and ventilator dependence). For further work-up, a CT chest excluded thymoma;a focused neurological exam was limited by sedation, and inpatient electrodiagnostics were not feasible. He received 5 days of intravenous immune globulin (40 mg), a Prednisone taper, and Rivastigmine 60 mg thrice daily. His symptoms improved and he was transferred to the floor. DISCUSSION: It is well established that coronaviruses exhibit neurotropism. However, it is unclear whether the novel coronavirus SARS-CoV-2 unmasks underlying neurologic illness or creates de novo disease. Critical care physicians are often tasked with making an initial diagnosis of neuromuscular disease (NMD). NMD is a known cause of complicated extubations. When the diaphragm and accessory respiratory muscles fatigue, respiratory decompensation ensues as full MV support is removed. In many cases, underlying illness is unmasked during this process of extubation. In our case, it is unknown whether infectious insult led to molecular mimicry and development of autoantibodies or unmasked latent neuromuscular disease. If the infection did cause his disease, it would be one of the first cases of COVID-associated MG to be published. Our case is a reminder that NMD is a secondary cause of extubation failure and may suggest MG as a cause of MV weaning failure secondary to COVID. CONCLUSIONS: Critical care physicians should be aware of this potential neuromuscular complication of COVID infection as it may complicate MV weaning, increase vent days, and prolong ICU stays. Reference #1: Collantes MEV, Espiritu AI, Sy MCC, Anlacan VMM, Jamora RDG. Neurological manifestations in covid-19 infection: A systematic review and meta-analysis. Can J Neurol Sci. 2021 Jan;48(1):66-76. Doi: 10.1017/cjn.2020.146. Epub 2020 Jul 15. PMID: 32665054. Reference #2: Huber M, Rogozinski S, Puppe W, Framme C, Hoglinger G, Hufendiek K, Wegner F. Postinfectious onset of myasthenia gravis in a COVID-19 patient. Front Neurol. 2020 Oct 6;11:576153. Doi: 10.3389/fneur.2020.576153. eCollection 2020. PMID: 33123081. Reference #3: Muralidhar Reddy Y, B SK, Osman S, Murthy JMK. Temporal association between SARS-CoV-2 and new-onset myasthenia gravis: Is it causal or coincidental? BMJ Case Rep. 2021 Jul 21;14(7):e244146. Doi: 10.1136/bcr-2021-244146. PMID: 34290032. DISCLOSURES: No relevant relationships by Jeffrey Li No relevant relationships by Anupa Nadkarni No relevant relationships by Justin Owens No relevant relationships by Jennifer Perry no disclosure on file for Hayley Sp res;

ACSM Newsbriefs

The article offers fitness news briefs on topics including announcement of annual rankings highlighting key health and fitness measures for the 100 largest cities in the United States by the ACSM's American Fitness Index;and different recovery strategies for optimizing exercise performance and recovery potential of a mind and body.

The Effects of COVID-19 on Skeletal Muscles, Muscle Fatigue and Rehabilitation Programs Outcomes.

Background and Objectives: Consequences due to infection with SARS-CoV-2 virus can have a direct impact on skeletal muscle, due to the fact that both cardiac and skeletal muscle tissue show robust ACE2(angiotensin-converting enzyme 2) expression, suggesting a potential susceptibility to SARS-CoV-2 infection in both types of tissues. From the articles analyzed we concluded that the musculoskeletal damage is firstly produced by the inflammatory effects, cytokine storm and muscle catabolism. However, myopathy, polyneuropathy and therapies such as corticoids were also considered important factors in muscle fatigue and functional incapacity. Pulmonary rehabilitation programs and early mobilization had a highly contribution during the acute phase and post-illness recovery process and helped patients to reduce dyspnea, increase the capacity of physical effort, overcome psychological disorders and improved the quality of their life. Materials and Methods: We have included in this review 33 articles that contain data on muscle damage following SARS-CoV-2 infection. We used the following keywords to search for articles: SARS-CoV-2, COVID-19, muscle weakness, muscle disease, muscle fatigue, neurological disorders. As a search strategy we used PubMed, Cochrane Database of Systematic Reviews; Database of Abstracts of Reviews of Effects and Health Technology Assessment Database to collect the information. We also have chosen the most recent articles published in the last 5 years. Conclusions: Muscular damage, as well as the decrease in the quality of life, are often a consequence of severe SARS-CoV-2 infection through: systemic inflammation, corticotherapy, prolonged bed rest and other unknown factors. Pulmonary rehabilitation programs and early mobilization had a highly contribution during the acute phase and post-illness recovery process and helped patients to reduce dyspnea, increase the capacity of physical effort, overcome psychological disorders and improve the quality of their life.

ADVERSE EVENTS after TWO DOSES of BNT162B2 ANTI-SARS-COV-2 VACCINE in PATIENTS with RHEUMATIC MUSCULOSKELETAL DISEASES: RESULTS from A SINGLE CENTER ITALIAN STUDY

Background: Vaccination against COVID19 is the most important prevention tool against the current pandemic. However, since the approval of anti-COVID19 mRNA vaccines by EMA, safety and tolerability in patients with rheumatic musculoskeletal diseases has always been a much-discussed topic, given their novel, unprecedented mechanism of action and the concern for potential disease fares. Objectives: To assess the safety and type of adverse events after two doses of BNT162b2 anti-SARS-CoV-2 vaccine in patients affected by rheumatologic diseases. Methods: 241 patients who received two doses of BNT162b2 were invited to take part to a follow-up live visit 2 months after completion of the primary vaccination cycle. Data regarding age, sex, diagnosis, treatment and adverse events after vaccination were collected for each patient during the visit. Pearson chi-square and Fisher exact tests were used to compare the distribution of each type of adverse event between male and female and among Rheumatoid Arthritis, Spondyloarthritis and Connective Tissue Disease patients. Results: Mean age of recruited patients was 57 years (IQR 49-65) and F:M ratio was 2.49:1 (172 F/69 M). Number and percentage of individuals for each disease category were represented as follows: Rheumatoid Arthritis 87 (36,10%), Spondyloarthritides 72 (29,88%), Connective Tissue Diseases 65 (26,97%), Autoinfammatory Diseases 4 (1,66%), Vasculitides 13 (5,39%). 42 subjects (17,42%) reported no adverse events, whereas local reactions such as pain and swelling at injection site were the most commonly reported side effect, (154 subjects, 63,9%, Table 1). Constitutional symptoms, comprising fatigue, muscle and joint pain, fever, chills and headache, were described in 54,77% of the interviews (132 subjects, Table 1). No patient experienced severe allergic reactions after vaccination. Statistical comparison among disease categories showed no differences in the distribution of adverse events. When analysing for sex, joint pain appeared to be reported signifcantly more frequently in male patients (p=0.002), while chills were more present in female patients (p=0.033). None of the interviewed subjects reported any sign or symptom relatable to disease fares. Conclusion: Vaccination with two doses of BNT162b2 was safe and generally well tolerated. No reports of signs or symptoms of disease reactivation were found in our cohort.

Sleep quality in patients in the rehabilitation phase after COVID-19 diagnosis

Introduction: The inflammatory process and multisystemic manifestation caused by Covid-19 infection can involve multiple sequelae with damage on physical, cognitive, psychological, and biological aspects. This condition results on poor quality of life, fatigue, dyspnea and sleep difficulties. The focus on sleep difficulties, the most common symptoms are related to night drowsiness and insomnia, but little is known about the clinical characteristics of these patients who develop this complication. Objective: Evaluate the main complaints and clinical signs in patients after COVID-19. - Rate the quality of sleep in post-COVID-19 Syndrome patients who have had mild, moderate and/or severe symptoms of the disease. Methods: Observational study and descriptive, with a quantitative approach to data. A general and a specific sleep quality questionnaire were applied to patients undergoing rehabilitation after the diagnosis of COVID-19, who did or did not need to be hospitalized, with symptoms that had started at least 5 weeks before the questionnaire response date. Participants who were unable to answer the questionnaires due to a deficit in understanding the questions asked, or who gave up on completing the questionnaires without finishing, were excluded. Results: 177 participants participated in the research, 124 men (70%) and 53 women (30%). 62.7% of participants reported at least one comorbidity and only 23 people (12.9%) were not vaccinated with any dose until participation in this study. With regard to hospital admission, 109 participants (61.6%) required admission to the ICU and of these, 57.8% (63) required orotracheal intubation, with prolonged hospital stay for more than 12 days. The most common symptoms after covid-19 were muscle fatigue (78.3%), excessive daytime sleepiness (51.4%), persistent cough (47.4%) and headache (47.1%). 81.4% of participants reported that they felt their sleep quality had worsened after the diagnosis of COVID-19. And after applying a specific questionnaire (PSQI), 93.7% of participants were classified as poor sleepers. There was a very strong correlation (r>0.9) with participants who assessed hospitalized and in invasive mechanical ventilation, with bad sleep quality. Conclusion: The post-COVID-19 Syndrome, associated with age, comorbidities, length of stay and use of invasive mechanical ventilation, were factors that are associated with a higher prevalence of sleep disorders.

Cardiopulmonary exercise testing in post-COVID-19 patients: Where does exercise intolerance come from?

Background: Post-COVID-19 persistent symptoms and exercise intolerance are poorly understood. Cardiopulmonary exercise testing (CPET) assessment is important to address the sources of the underlying symptoms and limitations. Purpose: To evaluate the source and magnitude of exercise intolerance in post-COVID-19 subjects via CPET. Methods: This cohort study assessed subjects with different SARS-CoV-2 illness severities. The propensity score matching method was used to select the control group. Patients with available CPET prior to SARS-CoV-2 infection were compared before and after COVID-19. Results: 288 subjects (144 post-COVID-19 and 144 matched-controls) were assessed. The median age was 43.0 years, and 57% were male, with different illness severity (60.4% mild, 20.8% moderate, 18.8% severe). Residual symptoms were reported in 41% of the sample. CPET was performed 14.4±9.4 weeks after disease onset, with exercise limitations being attributed to the peripheral muscle (91.7%), pulmonary (6.3%), and cardiovascular (2.1%) systems. Lower median percent-predicted peak oxygen consumption was observed in the severe subgroup (72.2%) compared to both mild (98.5%) and control subgroups (91.6%). Peak oxygen consumption (peakVO2), VO2 at the ventilatory thresholds (VO2 at VT), and heart rate differed among illnesses, severities, and controls. Conversely, ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse were similar (Figure 1). Additional subgroup analysis of 42 subjects with prior CPET revealed changes only on peak treadmill speed in the mild subgroup and additional reductions on peakVO2 and VO2 at VT in the moderate/severe subgroup (Figure 2), while ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse remained unchanged. Conclusions: Peripheral muscle fatigue was the most common etiology of exercise limitation in post-COVID-19 patients regardless of the SARS-CoV-2 illness severity. Our data suggest that treatment should emphasize comprehensive rehabilitation programs, including aerobic and muscle strengthening components. (Figure Presented).

COVID-19 disease in professional football players: symptoms and impact on pulmonary function and metabolic power during matches.

This study aimed at: (1) Reporting COVID-19 symptoms and duration in professional football players; (2) comparing players' pulmonary function before and after COVID-19; (3) comparing players' metabolic power (Pmet ) before and after COVID-19. Thirteen male players (Age: 23.9 ± 4.0 years, V̇O2peak : 49.7 ± 4.0 mL/kg/min) underwent a medical screening and performed a running incremental step test and a spirometry test after COVID-19. Spirometric data were compared with the ones collected at the beginning of the same season. Players' mean Pmet of the 10 matches played before COVID-19 was compared with mean Pmet of the 10 matches played after COVID-19. Players completed a questionnaire on COVID-19 symptoms and duration 6 months following the disease. COVID-19 positivity lasted on average 15 ± 5 days. "General fatigue" and "muscle fatigue" symptoms were reported by all players during COVID-19 and persisted for 77% (general fatigue) and 54% (muscle fatigue) of the players for 37 ± 28 and 38 ± 29 days after the disease, respectively. No significant changes in spirometric measurements were found after COVID-19, even though some impairments at the individual level were observed. Conversely, a linear mixed-effects model analysis showed a significant reduction of Pmet (-4.1 ± 3.5%) following COVID-19 (t = -2.686, p < 0.05). "General fatigue" and "muscle fatigue" symptoms may persist for several weeks following COVID-19 in professional football players and should be considered for a safer return to sport. Players' capacity to compete at high intensities might be compromised after COVID-19.

Healthy Ways to Cope with Stress: Home exercise advice for people during the COVID-19 By sEMG

Electromyography has been extensively used in a variety of fields. By using feature extraction to detect and analyze the surface EMG signal of Electromyography, muscle fatigue caused by daily life workout could be detected more timely. Here we intend to utilize this feature of using feature extraction on electromyography to offer professional advice for at home work out due to the deduction of outing caused by COVID-19. In this work, multiple time window (MTW) features have been used to distinguish the surface electromyography (sEMG) signals between muscle fatigue during arm movements by using Python. The sEMG signals are monitored from the biceps muscle of 3 healthy subjects. 4 window functions named boxcar function, hamming function, blackman function, and kaiser function and 24 features are extracted. 4 classifiers named Decision Tree, Random Forest, Support Vector Machine, and Naive Bayes are used in this research. The classifier using MTW features compared with the classifier without MTW feature. The Random Forest classifier has the greatest accuracy of 95.16%.

Post COVID-19 syndrome

Dyspnea and fatigue are the most frequent symptoms that can remain for a long time in the post-COVID-19 phase, especially in patients returning from prolonged bed rest in intensive care or in acute care wards. In all these patients, pulmonary rehabilitation (PR) plays an important role in promoting their recovery, improving their autonomy and quality of life, and should be started early. The programs must be tailored to the needs and clinical conditions of the patient, also taking advantage of the possibilities offered by tele-rehabilitation.

Central and Peripheral Fatigue in Physical Exercise Explained: A Narrative Review.

The study of the origin and implications of fatigue in exercise has been widely investigated, but not completely understood given the complex multifactorial mechanisms involved. Then, it is essential to understand the fatigue mechanism to help trainers and physicians to prescribe an adequate training load. The present narrative review aims to analyze the multifactorial factors of fatigue in physical exercise. To reach this aim, a consensus and critical review were performed using both primary sources, such as scientific articles, and secondary ones, such as bibliographic indexes, web pages, and databases. The main search engines were PubMed, SciELO, and Google Scholar. Central and peripheral fatigue are two unison constructs part of the Integrative Governor theory, in which both psychological and physiological drives and requirements are underpinned by homeostatic principles. The relative activity of each one is regulated by dynamic negative feedback activity, as the fundamental general operational controller. Fatigue is conditioned by factors such as gender, affecting men and women differently. Sleep deprivation or psychological disturbances caused, for example, by stress, can affect neural activation patterns, realigning them and slowing down simple mental operations in the context of fatigue. Then, fatigue can have different origins not only related with physiological factors. Therefore, all these prisms must be considered for future approaches from sport and clinical perspectives.

Self-injection of denosumab in clinical practice in the french pilote study

Objective: Describe characteristics of patients who self-inject denosumab and patterns of self-injection in France. Methods: PILOTE was a prospective observational study that evaluated persistence to denosumab over 24 months in France in postmenopausal women. Clinical information obtained through routine practice was recorded onto an eCRF, including the individual who injected subcutaneous denosumab (physician, nurse, patient, other). We conducted an ad hoc analysis of the patients in the study who self-injected denosumab. Results: In total, 478 patients were enrolled between June 2105 and February 2016. 27 patients self-injected denosumab at least once, with these patients distributed across multiple sites. Those who self-injected appeared slightly younger with longer duration of osteoporosis, and a higher proportion had a prior fracture and previous glucocorticoid and teriparatide treatment than the overall population (Table). Self-injected patients were also more likely to be living at home with family, have a University education, and be seen by a rheumatologist than a GP. Twelve patients self-injected from the beginning of the study, 15 self-injected after receiving injection from an HCP and 8 switched back to HCP injections after self-injection. Eleven of the 12 patients who self-injected from the beginning were persistent at 24 months. Six ADRs occurred in three self-injecting patients: one vertebral fracture, bone pain, muscle fatigue, myalgia, asthenia, pyelonephritis. Conclusion: Although numbers were small, self- administration of denosumab appeared feasible for women with postmenopausal osteoporosis and may be a valuable option, particularly in the context of the COVID-19 pandemic when office visits are restricted. (Table Presented).

An Indirect Approach to Analyze the Impact of Working Environment Restrictions Due To COVID 19 on Muscle Fatigue and Strength

The current research work seeks to analyze the changes in the muscle fatigue and strength, if any, due to the restrictions of use of facial mask while at work. The workers are required to perform tasks like lifting and pushing which range from moderate to heavy workloads. Alternative approach had to be used as the shop floor environment did not facilitate the use of standard laboratory setup for measurement of muscle fatigue. © IEOM Society International.

Effects of Core Stabilization Exercise Programs on Changes in Erector Spinae Contractile Properties and Isokinetic Muscle Function of Adult Females with a Sedentary Lifestyle

This study aimed to investigate the effect of core stabilization exercises on the contractile properties and isokinetic muscle function of adult females with a sedentary lifestyle. We enrolled 105 adult females. Tensiomyography was performed on the erector spinae, and the isokinetic muscular functional test was performed on the trunk at an angular velocity of 60°/s and 90°/s. All participants performed the exercise for 60 min per day, 3 times a week, for 7 weeks. A Wilcoxon signed-rank test was performed at a significance level of 0.05. Tensiomyography (TMG) of the erector spinae revealed no significant post-exercise change in the contraction time;however, there was a significant post-exercise increase in the maximum radial displacement and mean velocity until 90% of the TMG was displaced. Additionally, the isokinetic muscular functional test of the trunk revealed a significant post-exercise increase in almost all variables. Our findings demonstrated that the core stabilization exercise reduced stiffness in the erector spinae, increased the velocity of erector spinae contraction, and effectively improved the isokinetic muscular function of the trunk.

The influence of contraction type, prior performance of a maximal voluntary contraction and measurement duration on fine-wire EMG amplitude.

We aimed to investigate the impact of time on fine-wire (fw) electromyography (EMG) signal amplitude, and to determine whether any attenuation is confounded by task type. Twenty healthy participants were instrumented with fw and surface (s) EMG electrodes at the biceps brachii bilaterally. Participants held a weight statically with one arm and with the other arm either repeated the same task following a maximum voluntary contraction (MVC) or repeated dynamic elbow flexion/extension contractions. Each task was repeated for 30 s every five minutes over two hours. EMG amplitude was smoothed and normalized to time = 0. Stable median power frequency of the s-EMG ruled out the confounding influence of fatigue. Repeated-measures ANCOVAs determined the effect of electrode type and time (covariate) on EMG amplitude and the confounding impact of task type. During the isometric protocol, fw-EMG amplitude reduced over time (p = 0.002), while s-EMG amplitude (p = 0.895) and MPF (p > 0.05) did not change. Fw-EMG amplitude attenuated faster during the dynamic than the isometric protocol (p = 0.008) and there was evidence that the MVC preceding the isometric protocol impacted the rate of decline (p = 0.001). We conclude that systematic signal attenuation of fw-EMG occurs over time and is more pronounced during dynamic tasks.

Intrauterine growth restriction affects diaphragm function in adult female and male mice.

BACKGROUND: In utero diaphragm development is critically important for postnatal respiratory function and any disturbance to fetal development may lead to diaphragm dysfunction and respiratory complications in the postnatal period. Intrauterine growth restriction (IUGR) has been shown to affect respiratory function in a sex-dependent manner; however, the effect of IUGR on diaphragm function is unknown. AIM: This study used a maternal hypoxia-induced mouse model of IUGR to investigate the impact of IUGR on diaphragm function and structure in male and female adult offspring. MATERIALS AND METHODS: Pregnant BALB/c mice were housed under hypoxic conditions (10.5% O2 ) from gestational days 11 to 17.5 and then returned to normoxic conditions. Control mice were housed under normoxic conditions throughout pregnancy. At 8 weeks of age, offspring were euthanized and diaphragms isolated for functional assessment in organ bath experiments and for histological analysis. RESULTS: IUGR offspring were lighter at birth and remained lighter at 8 weeks of age compared to Controls. While diaphragm force (maximal or twitch) was not affected by treatment or sex, the IUGR group exhibited a longer half-relaxation time after twitch contractions compared to Control. Female offspring had a lower maximum rate of force development and higher fatigue resistance compared to males, independent of IUGR. There was no difference in the diaphragm myofibre cross-sectional area between groups or sexes. CONCLUSION: Sex and IUGR independently affect diaphragm contraction in adult mice without changes in structure. This study demonstrates that IUGR affects diaphragm contractile function in later life and could impair respiratory function if exacerbated under conditions of increased respiratory load.