Regular physical activity and endurance exercise training prevent age-related vascular endothelial dysfunction in the arm in men. However, the effects of physical activity and/or endurance exercise training in the legs, which have a greater predisposition for vascular disease, have not been completely elucidated. This study sought to examine the impact of aging, physical activity, and endurance exercise training on leg vascular function in men. Flow-mediated dilation (FMD) of the superficial femoral and popliteal arteries (SFA and PA, respectively) was assessed in a total of 39 men, comprised of 10 young sedentary (Y; 23 ± 2 yr), 8 older sedentary (OS; 76 ± 8 yr), 9 older physically active (OA; 71 ± 8 yr), and 12 older endurance exercise trained (OT) subjects with exceptional aerobic exercise capacity (V̇o2max) for their age (70 ± 3 yr, V̇o2max = 53 ± 6 mL·kg-1·min-1). FMD was lower in the OS group compared with the Y in the SFA (Y: 4.3 ± 2.1%, OS: 1.7 ± 1.0%, P = 0.005) and PA (Y: 5.8 ± 2.4%, OS: 1.9 ± 1.1%, P < 0.05). SFA and PA FMD were not different from OS in the OA group (SFA: 2.8 ± 1.5%; PA: 1.6 ± 1.0%) but were higher than OS in the OT group (SFA: 3.4 ± 2.3%, P = 0.043; PA: 4.2 ± 3.0%, P = 0.025) and not different from Y. There was evidence of a moderate-strong correlation between SFA (r = 0.32, P = 0.052) and PA (0.36, P = 0.037) FMD and V̇o2max but not physical activity levels. These findings suggest that habitual physical activity in general, and endurance exercise training in particular, diminishes the detrimental effect of aging on lower limb vascular function in men, and this may be linked to an augmented V̇o2max.NEW & NOTEWORTHY In the current study, we provide evidence of a relation between high levels of physical activity associated with lifelong endurance exercise training and protection from age-related declines in vascular endothelial function in the lower limb in men. Moreover, our findings suggest that aerobic fitness, in particular, may confer the benefits of endurance exercise training in maintaining lower limb endothelial function with advancing age.

SARS-CoV-2 may result in the development of new symptoms, known as long COVID, a few months after the original infection. It is elusive to what extent physical capacity in patients diagnosed with long COVID is impacted. We compared maximal oxygen uptake (V̇O2max), one of the single most important factors for cardiovascular health and mortality, expired lung volumes and air flow, oxygen cost of walking and 6-min-walking-test (6MWT), in 20 patients diagnosed with long COVID (11 males and 9 females; 44 ± 16 years (SD); 26.7 ± 3.8BMI, duration of acute phase 1.7 ± 1.2 weeks, tested 4 ± 3 months after long COVID diagnosis) with 20 healthy age and sex matched controls (11 males and 9 females; 44 ± 16 years; 25.9 ± 4.0BMI). Long COVID patients had a V̇O2max of 41.4 ± 16.2 mL∙kg−1∙min−1(men) and 38.2 ± 7.5 (women) and this was not different from controls. Similarly, mean spirometry measures in the patient group (VC; FVC; FEV1; FEV1/FVC) were also not different (85–106

Abstract The existence of spot reduction, exercise‐induced local body fat reduction, has been debated for half a century. Although the evidence is equivocal, no study has applied aerobic endurance training closely matching interventions for energy expenditure. Sixteen overweight (BMI: 29.8 ± 3.3(SD) kg m−2) males (43 ± 9 years) were randomized to: (1) abdominal endurance exercise (AG), combining treadmill running at 70% HRmax (27 min) with 4 × 4 min (30%–40% maximal strength, 1RM) of torso rotation and abdominal crunches (57 min), 4 days⋅week−1 for 10 weeks; or (2) control group (CG) performing only treadmill running (45 min) at 70% HRmax. Local fat mass was measured by dual‐energy x‐ray absorptiometry (DEXA), along with 1RM, and pulmonary oxygen uptake (to control energy expenditure during training). Trunk fat mass decreased more (697 g, 3%, p < 0.05) in AG (1170 ± 1093 g, 7%; p < 0.05) than in CG (no change). Total fat mass (AG: 1705 ± 1179 g, 6%; CG: 1134 ± 731 g, 5%; both p < 0.01) and body weight (AG: 1.2 ± 1.2 kg, 1%, p < 0.05; CG: 2.3 ± 0.9 kg, 3%, p < 0.01) decreased similarly in AG/CG. Torso rotation (AG: 32 ± 16 kg, 39%, p < 0.01; CG: no change) and abdominal crunch 1RM (AG: 35 ± 16 kg, 36%, p < 0.01; CG: 13 ± 12 kg, 17%, p < 0.05) increased more (p < 0.05/0.01) in AG than CG. Abdominal endurance exercise utilized more local fat than treadmill running, indicating that spot reduction exists in adult males.

Maximal oxygen uptake (V̇O2max) may be the single most important factor for long‐distance running performance. Interval training, enabling high intensity, is forwarded as the format that yields the largest increase in V̇O2max. However, it is uncertain if an optimal outcome on V̇O2max, anaerobic capacity, and running performance is provided by training with a high aerobic intensity or high overall intensity. Thus, we randomized 48 aerobically well‐trained men (23 ± 3 years) to three commonly applied interval protocols, one with high aerobic intensity (HIIT) and two with high absolute intensity (sprint interval training; SIT), 3× week for 8 weeks: (1) HIIT: 4 × 4 min at ~95% maximal aerobic speed (MAS) with 3 min active breaks. (2) SIT: 8 × 20 s at ~150% MAS with 10 s passive breaks. (3) SIT: 10 × 30 s at ~175% MAS with 3.5 min active breaks. V̇O2max increased more (p < 0.001) following HIIT, 4 × 4 min (6.5 ± 2.4%, p < 0.001) than SIT, 8 × 20 s (3.3 ± 2.4%, p < 0.001) and SIT, 10 × 30 s (n.s.). This was accompanied by a larger (p < 0.05) increase in stroke volume (O2‐pulse) following HIIT, 4 × 4 min (8.1 ± 4.1%, p < 0.001) compared with SIT, 8 × 20 s (3.8 ± 4.2%, p < 0.01) and SIT, 10 × 30 (n.s.). Anaerobic capacity (maximal accumulated oxygen deficit) increased following SIT, 8 × 20 s (p < 0.05), but not after HIIT, 4 × 4 min, nor SIT, 10 × 30 s. Long‐distance (3000‐m) endurance performance increased (p < 0.05–p < 0.001) in all groups (HIIT, 4 × 4 min: 5.9 ± 3.2%; SIT, 8 × 20 s: 4.1 ± 3.7%; SIT, 10 × 30 s: 2.2 ± 2.2%), with HIIT increasing more than SIT, 10 × 30 s (p < 0.05). Sprint (300‐m) performance exhibited within‐group increases in SIT, 8 × 20 s (4.4 ± 2.0%) and SIT, 10 × 30 s (3.3 ± 2.8%). In conclusion, HIIT improves V̇O2max more than SIT. Given the importance of V̇O2max for most endurance performance scenarios, HIIT should typically be the chosen interval format.

Maximal oxygen uptake (V̇O2max) is a pivotal factor for aerobic endurance performance. Recently, aerobic high‐intensity interval training (HIIT) was documented to be superior to sprint interval training (SIT) in improving V̇O2max in well‐trained males. However, as mounting evidence suggests that physiological responses to training are sex‐dependent, examining the effects of HIIT versus SIT on V̇O2max, anaerobic capacity, and endurance performance in females is warranted.

Patients with inflammatory rheumatic disease (IRD) have attenuated muscle strength in the lower extremities, resulting in impaired physical function and quality of life. Although maximal strength training (MST), applying heavy resistance, is documented to be a potent countermeasure for such attenuation, it is uncertain if it is feasible in IRD given the pain, stiffness, and joint swelling that characterize the population. 23 patients with IRD (49 ± 13 years; 20 females/3 males), diagnosed with spondyloarthritis, rheumatoid arthritis, or systemic lupus erythematosus, were randomized to MST or a control group (CG). The MST group performed four × four repetitions dynamic leg press two times per week for 10 weeks at ~ 90% of one repetition maximum (1RM). Before and after training 1RM, rate of force development (RFD), and health-related quality of life (HRQoL) were measured. Session attendance in the MST group was 95%, of which 95% conducted according to MST protocol. Furthermore, MST increased 1RM (29 ± 12%, p = 0.001) and early and late phase RFD (33–76%, p < 0.05). All improvements were different from the CG (p < 0.05). MST also resulted in HRQoL improvements in the dimensions; physical functioning, general health, and vitality (p < 0.05). Physical functioning was associated with 1RM (rho = 0.55, p < 0.01) and early phase RFD (rho = 0.53–0.71, p < 0.01; different from CG p < 0.05). Despite being characterized by pain, stiffness, and joint swelling, patients with IRD appear to tolerate MST well. Given the improvements in 1RM, RFD, and HRQoL MST should be considered as a treatment strategy to counteract attenuated muscle strength, physical function, and HRQoL. Trial registration: ClinicalTrials.gov, NCT04998955, retrospectively registered.

Background Physical inactivity remains the largest risk factor for the development of cardiovascular disease worldwide. Wearable devices have become a popular method of measuring activity-based outcomes and facilitating behavior change to increase cardiorespiratory fitness (CRF) or maximal oxygen consumption (VO2max) and reduce weight. However, it is critical to determine their accuracy in measuring these variables. Objective This study aimed to determine the accuracy of using a smartphone and the application Myworkout GO for submaximal prediction of VO2max. Methods Participants included 162 healthy volunteers: 58 women and 104 men (17-73 years old). The study consisted of 3 experimental tests randomized to 3 separate days. One-day VO2max was assessed with Metamax II, with the participant walking or running on the treadmill. On the 2 other days, the application Myworkout GO used standardized high aerobic intensity interval training (HIIT) on the treadmill to predict VO2max. Results There were no significant differences between directly measured VO2max (mean 49, SD 14 mL/kg/min) compared with the VO2max predicted by Myworkout GO (mean 50, SD 14 mL/kg/min). The direct and predicted VO2max values were highly correlated, with an R2 of 0.97 (P<.001) and standard error of the estimate (SEE) of 2.2 mL/kg/min, with no sex differences. Conclusions Myworkout GO accurately calculated VO2max, with an SEE of 4.5% in the total group. The submaximal HIIT session (4 x 4 minutes) incorporated in the application was tolerated well by the participants. We present health care providers and their patients with a more accurate and practical version of health risk estimation. This might increase physical activity and improve exercise habits in the general population.

Background Patients with inflammatory rheumatic diseases (IRDs) experience disease-related barriers to physical training. Compared with the general population, IRD patients are reported to have reduced maximal oxygen uptake (VO2max) and physical activity levels. Supervised high-intensity interval training (HIIT) is documented to counteract the reduced VO2max and poor cardiovascular health associated with IRDs. However, supervised HIIT is resource demanding. Objective This study sought to investigate if self-administered 4×4-min HIIT guided by a smartphone app (Myworkout GO) could yield similar HIIT-induced effects as standard 4×4-min HIIT performed under the guidance and supervision of health care professionals. The effects studied were on VO2max and health-related quality of life (HRQoL). Methods Forty patients (33 female patients, mean age 48 years, SD 12 years; 7 male patients, mean age 52 years, SD 11 years) diagnosed with rheumatoid arthritis, spondyloarthritis, or systemic lupus erythematosus were randomized to a supervised group (SG) or an app group (AG). Both groups were instructed to perform 4×4-min intervals with a rate of perceived exertion of 16 to 17, corresponding to 85% to 95% of the maximal heart rate, twice a week for 10 weeks. Treadmill VO2max and HRQoL measured using RAND-36 were assessed before and after the exercise period. Results VO2max increased (P<.001) in both groups after 10 weeks of HIIT, with improvements of 3.6 (SD 1.3) mL/kg/min in the SG and 3.7 (SD 1.5) mL/kg/min in the AG. This was accompanied by increases in oxygen pulse in both groups (P<.001), with no between-group differences apparent for either measure. Improvements in the HRQoL dimensions of bodily pain, vitality, and social functioning were observed for both groups (P<.001 to P=.04). Again, no between-group differences were detected. Conclusions High-intensity 4×4-min interval training increased VO2max and HRQoL, contributing to patients’ reduced cardiovascular disease risk, improved health and performance, and enhanced quality of life. Similar improvements were observed following HIIT when IRD patients were guided using perceived exertion by health care professionals or the training was self-administered and guided by the app Myworkout GO. Utilization of the app may help reduce the cost of HIIT as a treatment strategy in this patient population. Trial Registration ClinicalTrials.gov NCT04649528; https://clinicaltrials.gov/ct2/show/NCT04649528

Subacromial pain syndrome (SAPS) defined as pain of nontraumatic origin localized around the acromion, is a debilitating, common, and often chronic condition. Among many proposed underlying causes of SAPS, hypoperfusion and hypoxic conditions in and around the tendons may be an intrinsic cause of SAPS. PURPOSE:This study aimed to determine if adding high-intensity aerobic interval training (HIIT) of the rotator cuff to usual care was feasible in SAPS and improved shoulder endurance more than usual care alone, as well as to examine the influence on shoulder pain and disability and the response of tendinous microcirculation after HIIT. METHODS:Twenty-one subjects with chronic SAPS were randomized to two groups: experimental group (EG; n = 13) receiving HIIT in addition to treatment as usual and control group (CG; n = 8) receiving treatment as usual. Before and after 8 wk of exercise therapy, endurance performance was assessed by an incremental abduction exercise of the arm to exhaustion (TTE). Pain and disability was assessed by the shoulder pain and disability index (SPADI). Contrast-enhanced ultrasound of the musculus supraspinatus and tendon was utilized to indicate tendon blood flow. RESULTS:Endurance in the TTE test improved by an estimated 233 s more on average in EG than in CG (P = 0.001; 95% confidence interval, 102 to 363). The SPADI score was reduced 22 points more on average in EG (P = 0.017; 95% confidence interval, -40 to -5). The change from pretest to posttest was significant in EG for both TTE test and SPADI improvement (P < 0.001). EG also experienced less pain during exercise after the intervention compared with CG (P < 0.001). Contrast-enhanced ultrasound indicated an increase in tendinous blood flow in EG (P = 0.019). CONCLUSIONS:HIIT rotator cuff exercise seems to be a feasible intervention in SAPS, increasing endurance performance more than usual care alone.

Introduction: Hip fractures predominantly occur in the geriatric population and results in increased physical inactivity and reduced independency, largely influenced by a downward spiral of ambulatory capacity, related to loss of skeletal muscle strength and postural stability. Thus, effective postoperative treatment, targeting improvements in muscle strength, is sought after. Materials & Methods: Twenty-one hip fracture patients (>65 yr) were randomized to 8 weeks of either conventional physiotherapy control group (CG), or leg press and hip abduction maximal strength training (MST) 3 times per week. MST was performed applying heavy loads (85-90% of 1 repetition maximum; 1RM) and 4-5 repetitions in 4 sets. Maximal strength (bi- and unilateral 1RM), postural stability (unipedal stance test; UPS), and DEXA-scan bone mineral content/ density (BMC/BMD) were measured before and after the 8-week rehabilitation. Results: Both MST and conventional physiotherapy improved bilateral leg press 1RM by 41 ± 27 kg and 29 ± 17 kg, respectively (both p < 0.01), while unilateral leg press 1RM only increased after MST (within group and between groups difference: both p < 0.05). MST also resulted in an increase in abduction 1RM in both the fractured (5 kg, 95%CI: 2-7; p < 0.01) and healthy limb (6 kg, 95%CI: 3-9; p < 0.01), while no such improvement was apparent in the CG (between groups difference: p < 0.01). Finally, MST improved UPS of the fractured limb (p < 0.05). No differences were observed in BMC or BMD following the 8 weeks. Discussion: Early postoperative MST improved lower extremities maximal muscle strength more than conventional physiotherapy and was accompanied by improvements in postural stability. Conclusion: Implementing MST in early rehabilitation after hip fracture surgery should be considered as a relevant treatment to curtail the downward spiral of reduced ambulatory capacity typical for this patient group, possibly reducing the risk of recuring falls and excess mortality. Trial Registration: https://clinicaltrials.gov/ct2/show/NCT03030092

This randomized, controlled trial documents that supervised high-intensity strength training improves efferent neural drive, maximal muscle strength, rate of force development, and functional performance in patients with Parkinson’s disease (PD). In contrast, no differences were observed in these outcome variables in patients receiving conventional treatment consisting of recreational physical activity with low-to-medium intensity. Consequently, this study advocates that high-intensity strength training should be implemented in the clinical treatment of PD patients.

Subacromial pain syndrome (SAPS) defined as pain of non-traumatic origin localized around the acromion, is a debilitating, common and often chronic condition. Among many proposed underlying causes of SAPS, hypoperfusion and hypoxic conditions in and around the tendons may be an intrinsic cause of SAPS. Exercise therapy with low load is the advocated treatment of choice for SAPS. PURPOUSE: To determine if high intensity aerobic interval training (HIIT) of the rotator cuff was feasible, more effective in improving endurance and reducing pain compared to low intensity exercises. Additionally, to examine the response of tendinous microcirculation following the exercise therapy. METHODS: 21 subjects with chronic SAPS randomized to two groups: HIIT (n=13) and control group (CG) (n=8) was tested before and after 8 weeks of exercise therapy. Endurance performance was assessed by an incremental abduction adduction exercise of the arm to exhaustion (TTE). Contrast enhanced ultrasound (CEUS) of the m. supraspinatus and tendon was utilized to indicate tendon blood flow. Limitations in daily life was assessed by the shoulder pain and disability index (SPADI). RESULTS: Endurance in the TTE-test improved by an estimated 233 seconds more on average in HIIT than in CG (p=0.001, 95%CI: 102 to 363), the change was significant in HIIT (p<0.001), no change was seen in CG. The SPADI score was reduced 22 points more on average in HIIT (p=0.017, 95%CI: -40 to -5). The change from pre to post-test was significant in HIIT(p<0.001), but not in the CG. HIIT also experienced less pain during exercise after the intervention compared to CG (p<0.001). CEUS indicated an increase in tendinous blood flow in the HIIT group (p=0.019), no change was observed in CG. CONCLUSIONS: HIIT rotator cuff exercise appear to be a feasible intervention in SAPS, reducing pain and increasing endurance performance more than exercise with low load. CEUS indicate that HIIT may increase tendon microcirculation, thus abating a potential hypoperfused/ hypoxic state underlying the condition.

High-intensity interval training (HIIT) is documented to counteract the reduced maximal oxygen uptake (V̇O2max) and poor cardiovascular health associated with inflammatory rheumatic disease (IRS). However, supervised HIIT is resource demanding. PURPOSE: This study sought to investigate if guidance by a smartphone application (APP: Myworkout GO) could yield similar HIIT-induced effects as supervision by healthcare professionals. METHODS: Thirty-four adults (27 females, 50±11 yrs; 7 males, 52±10 yrs), diagnosed with rheumatoid arthritis, spondyloarthritis or systemic lupus erythematosus were randomized to a supervised group (SG) or an APP group (AG). Both groups performed 4x4 minute intervals with an intensity corresponding to 85-95% of HRmax twice a week for 10 weeks. Treadmill V̇O2max and health-related quality-of-life (HRQoL), measured using SF-36, was assessed before and after the exercise period. RESULTS: V̇O2max increased (p<0.001) in both groups, revealing 3.6±1.4 (SG) and 3.7±1.5 mL·kg-1·min-1 (AG) improvements, with no between-group differences apparent. Improvements in the following HRQoL dimensions; bodily pain, vitality, social functioning and emotional wellbeing were observed for both groups (all p<0.001–0.05). Again, with no between-group differences detected. CONCLUSION: HIIT increased V̇O2max and HRQoL, contributing to the patients´ reduced cardiovascular disease risk, improved health, performance, and enhanced quality of life. Similar improvements were observed if IRS patients were guided by healthcare professionals or an APP, suggesting that utilization of the APP may be excellent in reducing the costs of HIIT as a treatment strategy in this patient population.

In patients with chronic obstructive pulmonary disease (COPD), exercise training-induced improvements in peak O2 uptake (V̇O2peak) are reliant on adaptations beyond the lungs, particularly in skeletal muscle. Muscle V̇O2peak is determined by the integration of convective and diffusive O2 transport, which are markedly diminished in COPD. It remains to be determined how these components of O2 transport respond to exercise training and if their adaptation is compromised in COPD. PURPOSE: To test the hypothesis that exercise training improvements in muscle convective and diffusive O2 transport, and therefore V̇O2peak, would not be attenuated in patients with COPD compared to matched controls. METHODS: Metabolic and vascular adaptations to single leg knee extensor exercise (KE) training (1 h, 3 times a week for 8 weeks) were compared between 8 patients with severe COPD (FEV1±SE=0.9±0.1 L, 30% of predicted) and 8 controls matched for age and physical activity. Femoral arterial and venous blood samples, in conjunction with thermodilution, were used to determine muscle O2 transport and utilization at peak KE. RESULTS: Training increased muscle convective O2 transport in the controls (0.69±0.07 vs. 0.80±0.10 l/min, p<0.05), but not in the patients with COPD (0.44±0.06 vs. 0.49±0.08 l/min, p>0.05). Muscle diffusive O2 transport was increased with training in both the patients (6.6±0.8 vs. 9.1±0.1.2 ml/min/mmHg) and controls (10.4±0.9 vs. 13.3±0.9 ml/min/mmHg) (each p<0.05), which equated to an 86% training response in the patients relative to the controls. Training increased V̇O2peak in the patients with COPD (0.27±0.04 vs. 0.34±0.05 l/min) and controls (0.42±0.05 vs. 0.58±0.07 l/min) and peak work rate in the patients (12±2 vs. 16±2 W) and controls (24±4 vs. 36±4 W) (each p<0.05), which equated to a 44% (V̇O2peak) and 33% (peak work rate) training response in the patients relative to the controls. CONCLUSION: These findings document limited plasticity in convective O2 transport to the muscle, but relatively conserved plasticity in muscle diffusive O2 transport with exercise training in COPD. Thus, despite a near restoration of muscle diffusive O2 transport, the improvements in muscle V̇O2peak and peak work rate in patients with COPD were constrained by the limited plasticity in convective O2 transport.

Key points Peak oxygen uptake, a primary determinant of prognosis, mortality and quality of life, is diminished in patients with chronic obstructive pulmonary disease (COPD), with mounting evidence supporting an important role for peripheral dysfunction, particularly within skeletal muscle. In patients with severe COPD and activity‐matched controls, muscle oxygen transport and utilization were assessed at peak effort during single‐leg knee‐extensor exercise (KE), where ventilation is assumed to be submaximal. This strategy removes ventilation as the major constraint to exercise capacity in COPD, allowing maximal muscle function to be attained and evaluated. During maximal KE, both convective arterial oxygen delivery to the skeletal muscle microvasculature and subsequent diffusive oxygen delivery to the mitochondria were diminished in patients with COPD compared to control subjects. These findings emphasize the importance of factors, beyond the lungs, that influence exercise capacity in this patient population and may, ultimately, influence the prognosis, mortality and quality of life for patients with COPD. AbstractPeak oxygen uptake (), a primary determinant of prognosis, mortality and quality of life, is diminished in patients with chronic obstructive pulmonary disease (COPD). Mounting evidence supports an important role of the periphery, particularly skeletal muscle, in the diminished with COPD. However, the peripheral determinants of have not been comprehensively assessed in this cohort. Thus, the hypothesis was tested that both muscle convective and diffusive oxygen (O2) transport, and therefore skeletal muscle peak O2 uptake (), are diminished in patients with COPD compared to matched healthy controls, even when ventilatory limitations (i.e. attainment of maximal ventilation) are minimized by using small muscle mass exercise. Muscle O2 transport and utilization were assessed at peak exercise from femoral arterial and venous blood samples and leg blood flow (by thermodilution) in eight patients with severe COPD (forced expiratory volume in 1s (FEV1) ± SEM = 0.9 ± 0.1 l, 30% of predicted) and eight controls during single‐leg knee‐extensor exercise. Both muscle convective O2 delivery (0.44 ± 0.06 vs. 0.69 ± 0.07 l min−1, P < 0.05) and muscle diffusive O2 conductance (6.6 ± 0.8 vs. 10.4 ± 0.9 ml min−1 mmHg−1, P < 0.05) were ∼1/3 lower in patients with COPD than controls, resulting in an attenuated in the patients (0.27 ± 0.04 vs. 0.42 ± 0.05 l min−1, P < 0.05). When cardiopulmonary limitations to exercise are minimized, the convective and diffusive determinants of , at the level of the skeletal muscle, are greatly attenuated in patients with COPD. These findings emphasize the importance of factors, beyond the lungs, that may ultimately influence this population's prognosis, mortality and quality of life.

Peak oxygen uptake (V̇O2peak), a primary determinant of prognosis, mortality, and quality of life, is diminished in patients with chronic obstructive pulmonary disease (COPD). Of importance, even after lung function is restored, by lung transplant, V̇O2peak remains markedly attenuated, emphasizing the critical importance of peripheral dysfunction in this pathology. However, the peripheral determinants of V̇O2peak in patients with COPD remain poorly understood. Therefore, the purpose of this investigation was to assess the peripheral determinants of V̇O2peak in patients with COPD, to better understand disease‐related peripheral adaptations. Oxygen transport and utilization at peak single‐leg knee‐extensor exercise were assessed from arterial and femoral venous oxygenation measurements and leg blood flow (by thermodilution) in 8 patients with COPD (FEV1 = 0.9 ± SE 0.1 L, 30% of predicted) and 8 well‐matched control subjects. This exercise modality was utilized to minimize cardiopulmonary exercise limitations. Muscle convective O2 delivery (0.44 ± 0.06 vs. 0.69 ± 0.07 l/min, p<0.05) and muscle diffusive O2 conductance (6.6 ± 0.8 vs. 10.4 ± 0.9 ml/min/mmHg, p<0.05) were both ~1/3 lower in COPD patients than control subjects, resulting in a significantly attenuated leg V̇O2peak in the patients (0.27 ± 0.04 vs. 0.42 ± 0.05 l/min, p<0.05). Thus, in an exercise paradigm that minimizes cardiopulmonary limitations, the convective and diffusive components of oxygen transport within skeletal muscle, key determinants of V̇O2peak, are markedly diminished in patients with COPD. These findings emphasize the importance of peripheral factors, beyond the lungs, that limit exercise capacity, exacerbate inactivity, and increase the risk for cardiovascular disease in patients with COPD.Support or Funding InformationSupported by National Heart, Lung, and Blood Institute Grant HL‐091830This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Based on the strong linear relationship between heart rate (HR) and oxygen consumption, the Åstrand–Ryhming cycle ergometer test (Astrand and Ryhming in J Appl Physiol 7:218–221, 1954) is a widely used submaximal test to predict whole body maximal oxygen consumption ( V̇O_2max ). However, a similar test predicting peak oxygen consumption ( V̇O_2peak ) in the upper extremities is not established, and may be very useful for individuals unable to use their lower extremities or/and if separation of upper extremity aerobic capacity is sought after. Thus, the aim of the current study was to develop a submaximal test predicting V̇O_2peak in arm-cycling. Forty-nine healthy volunteers (25 women: 38 ± 13 years; 24 men: 39 ± 12 years) tested arm-cycle V̇O_2peak on a protocol with 4-min, 21-W increments to exhaustion. The data were contrasted to treadmill V̇O_2max values. Arm-cycle V̇O_2peak was 66 ± 8

Efferent neural drive during strong muscle contractions is attenuated with age, even after life-long strength training. However, it is unknown if this deterioration may impede contralateral neural plasticity, and limit the clinical value of unilateral strength training. We assessed muscle force-generating capacity, evoked potentials recordings (V-wave and H-reflex normalized to M-wave; V/M-ratio and H/M-ratio) and voluntary activation (VA) in the plantar flexors of the contralateral limb following unilateral maximal strength training (MST) with the dominant limb for 3 weeks (nine sessions). Twenty-three 73 ± 4(SD) year old males were randomized to a MST group (N = 11), exercising with an intensity of ~90% of maximal strength, or a control group (CG, N = 12). MST improved contralateral maximal strength (107.6 ± 27.0 to 119.1 ± 34.8 Nm; 10%) and rate of force development (197.3 ± 54.1 to 232.8 ± 77.7 Nm s-1; 18%) (both p < .05). These strength gains were associated with (r = 0.465-0.608) an enhanced soleus V/M-ratio (0.12 ± 0.09 to 0.21 ± 0.17) and VA (79.5 ± 5.1 to 83.3 ± 5.2%) (all p < .05). H/M-ratio (10% maximal strength) remained unaltered after MST, and no changes were apparent in the CG. In conclusion, cross-limb effects in older adults are regulated by efferent neural drive enhancement, and advocate the clinical relevance of MST to improve neuromuscular function in individuals with conditions that results in unilateral strength reductions.