Physiological Evaluation for Endurance Exercise Prescription in Sickle Cell Disease Purpose Although strenuous exercise may expose sickle cell disease (SCD) patients to risks of vaso-occlusive crisis, evidence suggests that regular endurance exercise may be beneficial. This study aimed to test (i) the safety and usefulness of a submaximal incremental exercise in evaluating physical ability of SCD patients and identify a marker for the management of endurance exercise and (ii) the feasibility of endurance exercise sessions in SCD patients. Methods Twenty adults with SCD (12 men and 8 women) performed a submaximal incremental exercise used to determine the first lactate threshold (LT1) and stopped as soon as blood lactate concentration ([lactate]b) reached ≥4 mmol·L−1. Fifteen of those patients (8 men and 7 women) also performed three 30-min endurance exercise sessions at ~2.5 mmol·L−1 of [lactate]b on separate occasions. Results LT1 occurred at 47 ± 3 and 33 ± 3 W for men and women, respectively, demonstrating the extreme deconditioning and, thus, low physical ability of adult SCD patients. During endurance exercise, peripheral oxygen saturation and [lactate]b most often remained stable and within acceptable ranges. Conclusions The proposed strategy of submaximal incremental exercise allowed safe determination of LT1, an important parameter of patients’ physical ability. The study also demonstrated the feasibility and safety of individually tailored endurance exercises at ~2.5 mmol·L−1 of [lactate]b. These latter results suggest that endurance training programs may be considered for adult SCD patients and that the method proposed here may be helpful in that regard.

Cardiopulmonary Profile of Individuals with Intellectual Disability Introduction Individuals with intellectual disabilities (ID) are often sedentary and have low fitness levels. Current knowledge supports the existence of physiological barriers resulting in low fitness and exercise intolerance in individuals with Down syndrome, which might be applicable to other ID etiologies. If physiological barriers exist in ID, this would require adaptation of the physical activity guidelines. Purpose The aim of this study was to assess differences in cardiopulmonary profiles, including maximal oxygen uptake, during a cardiopulmonary exercise test in individuals with ID without Down syndrome and healthy controls. Methods Participants performed an incremental cardiopulmonary exercise test on a treadmill until exhaustion. Outcomes were peak heart rate (HRpeak), absolute peak oxygen uptake (V˙O2peak), relative V˙O2peak, peak minute ventilation, peak CO2 expenditure, oxygen uptake efficiency slope, V˙E/V˙CO2 slope, absolute O2 pulse, relative O2 pulse, difference from predicted HRpeak, HR reserve, RERpeak, ventilatory threshold (VT), and VT as a percentage of V˙O2peak. Differences between groups were analyzed with Student’s t-tests and multiple linear regression after adjusting for potential confounders (sex, age, body mass index, and activity level). Results Individuals with ID had worse outcomes on all of the cardiopulmonary outcomes, except for VT expressed as a percentage of V˙O2peak and V˙E/V˙CO2 slope (P < 0.05). Having ID was an independent predictor of reduced physiologic function during exercise (P < 0.05). Conclusion These results demonstrate that individuals with ID present exercise intolerance potentially related to lower HRpeak and impairments in ventilatory function, and these results also suggest the possibility of peripheral muscle hypoperfusion. Existing physical activity guidelines likely underestimate the actual intensity of activity performed by individuals with ID and need to be adapted.

Diverse Exercises Similarly Reduce Older Adults’ Mobility Limitations Introduction/Purpose Little is known about the comparative effectiveness of exercise programs, especially when delivered at a high intensity, in mobility-limited older adults. We compared the effects of 25 sessions of high-intensity agility exergaming (EXE) and stationary cycling (CYC) at the same cardiovascular load on measured and perceived mobility limitations, balance, and health-related quality of life in mobility-limited older adults. Methods Randomized to EXE (n = 28) and CYC (n = 27), mobility-impaired older adults (age 70 yr) exercised five times per week for 5 wk at 80% of age-predicted maximal heart rate. Waitlisted controls did not exercise (n = 28). Results Groups did not differ at baseline in any outcomes (P > 0.05). The primary outcomes (The Short Form-36-Health Survey: EXE, 6.9%; effect size, 2.2; CYC, 5.5%, 1.94; Western Ontario and McMaster Universities Osteoarthritis Index: EXE, −27.2%, −3.83; CYC, −17.2, −2.90) improved similarly (P > 0.05). Secondary outcomes, including body mass (−3.7%), depression (−18%), and walking capacity (13.5%) also improved (P < 0.05) similarly after the two interventions. Activities of daily living, Berg Balance Score, BestTest scores, and Dynamic Gait Index improved more (P < 0.05) after EXE than CYC. Center of pressure of standing sway path improved in one of six tests only after EXE (P < 0.05). Postexercise cardiovascular response improved in EXE (P = 0.019). CON did not change in any outcomes (P > 0.05). Conclusions When matched for cardiovascular and perceived effort, two diverse high-intensity exercise programs improved health-related quality of life, perceived mobility limitation, and walking capacity similarly and balance outcomes more in mobility-limited older adults, expanding these older adults’ evidence-based exercise options to reduce mobility limitations.

Blood Flow–restricted Exercise Does Not Induce a Cross-Transfer of Effect: A Randomized Controlled Trial Purpose The goal of this trial was to determine whether low-load blood flow–restricted (BFR) exercise of appendicular muscles induces a cross-transfer of effect to the trunk extensor (TE) muscles, such that low-load TE exercise would enhance TE size and function to a greater extent than standard low-load exercise in people with recurrent low back pain (LBP). We also investigated the direct effects of BFR exercise in the appendicular muscles. Methods Thirty-two adults with recurrent, nonspecific LBP were randomized into two groups: Appendicular BFR exercise (BFR exercise) or control exercise (CON exercise). All participants trained (two times per week) for 10 wk, with a 12-wk follow-up. Participants performed three sets of leg extension (LE), plantar flexion (PF), and elbow flexion (EF) exercises followed by low-load TE exercise without BFR. Outcome measures included magnetic resonance imaging–derived muscle size (quadriceps and TE), strength (LE, PF, EF, and TE), and endurance (LE and TE). Results There was no evidence for a cross-transfer of effect to the TE. There was also no statistically significant enhancement of limb skeletal muscle size or function of BFR relative to CON exercise at any time point; though, moderate effect sizes for BFR exercise were observed for enhanced muscle size and strength in the leg extensors. Conclusions Low-load BFR exercise of the appendicular muscles did not result in a cross-transfer of effect to the TE musculature. There was also no significant benefit of low-load BFR exercise on the appendicular muscle size and function, suggesting no benefit from low-load BFR exercise in adults with recurrent, nonspecific LBP.

High-Frequency Stimulation on Skeletal Muscle Maintenance in Female Cachectic Mice Cancer cachexia, an unintentional body weight loss due to cancer, affects patients’ survival, quality of life, and response to chemotherapy. Although exercise training is a promising intervention to prevent and treat cancer cachexia, our mechanistic understanding of cachexia’s effect on contraction-induced muscle adaptation has been limited to the examination of male mice. Because sex can affect muscle regeneration and response to contraction in humans and mice, the effect of cachexia on the female response to eccentric contraction warrants further investigation. Purpose The purpose of this study was to determine whether high-frequency electric stimulation (HFES) could attenuate muscle mass loss during the progression of cancer cachexia in female tumor-bearing mice. Methods Female wild-type (WT) and ApcMin/+ (Min) mice (16–18 wk old) performed either repeated bouts or a single bout of HFES (10 sets of 6 repetitions, ~22 min), which eccentrically contracts the tibialis anterior (TA) muscle. TA myofiber size, oxidative capacity, anabolic signaling, and catabolic signaling were examined. Results Min had reduced TA muscle mass and type IIa and type IIb fiber sizes compared with WT. HFES increased the muscle weight and the mean cross-sectional area of type IIa and type IIb fibers in WT and Min mice. HFES increased mTOR signaling and myofibrillar protein synthesis and attenuated cachexia-induced AMPK activity. HFES attenuated the cachexia-associated decrease in skeletal muscle oxidative capacity. Conclusion HFES in female mice can activate muscle protein synthesis through mTOR signaling and repeated bouts of contraction can attenuate cancer-induced muscle mass loss.

Kinetics of Left Ventricular Mechanics during Transition from Rest to Exercise Purpose At the onset of physical exercise, oxygen (O2) transport adapts to meet the working muscle O2 demands. Cardiac output abruptly increases through the concomitant changes of HR and stroke volume (SV), which is conditioned by the left ventricular (LV) function. The purpose of this study was to investigate the contribution of many LV diastolic and systolic function parameters, including twist–untwist mechanics, to SV adaptation during the first minutes after exercise onset. Methods Diastolic and systolic myocardial strains and twist were monitored by two-dimensional speckle-tracking echocardiography with high temporal resolution in 28 young men (mean age, 23 ± 4 yr) who performed five similar constant work-load exercises on a cycloergometer (target HR: 125 bpm). Two-dimensional cine-loops were recorded every 15 s during the first minute of exercise, and then every 30 s for the next 3 min. Results During the first 60 s of exercise, SV (from 104 ± 15 mL to 126 ± 21 mL, P < 0.001) increased concomitantly with LV strain and strain rates. Early filling was the main SV determinant during this phase, probably linked to the increase of venous return (at the very beginning of exercise), LV relaxation (from 1.5 ± 0.3 s to 2.5 ± 0.4 s, P < 0.001) and untwisting (from −78 ± 34°·s−1 to −165 ± 61°·s−1, P < 0.001). After the first minute, SV remained constant, whereas LV untwisting continued to increase (from −165 ± 61°·s−1 to −187 ± 60°·s−1, P < 0.001) and the other systolic and diastolic parameters reached a plateau. Conclusions This study gives new mechanical insights into LV kinetics to address the challenge of SV response at the onset of exercise.

Weight Training and Risk of 10 Common Types of Cancer Introduction Ample data support that leisure time aerobic moderate to vigorous physical activity (MVPA) is associated with lower risk of at least seven types of cancer. However, the link between muscle-strengthening activities and cancer etiology is not well understood. Our objective was to determine the association of weight lifting with incidence of 10 common cancer types. Methods We used multivariable Cox regression to estimate hazard ratios (HR) and 95% confidence intervals (CI) for association of weight lifting with incidence of 10 cancer types in the National Institutes of Health-American Association of Retired Persons Diet and Health Study follow-up. Weight lifting was modeled continuously and categorically. Dose–response relationships were evaluated using cubic restricted spline models. We explored whether associations varied by subgroups defined by sex, age, and body mass index using the Wald test for homogeneity. We examined joint categories of MVPA and weight lifting in relation to cancer risk for significant associations. Results After adjusting for all covariates including MVPA, we observed a statistically significant lower risk of colon cancer (Ptrend = 0.003) in individuals who weight lifted; the HR and 95% CI associated with low and high weight lifting as compared with no weight lifting were 0.75 (95% CI, 0.66–0.87) and 0.78 (95% CI, 0.61–0.98), respectively. The weight lifting-colon cancer relationship differed between men and women (any weight lifting vs no weight lifting: HRmen = 0.91; 95% CI, 0.84–0.98; HRwomen = 1.00; 95% CI, 0.93–1.08; Pinteraction = 0.008). A lower risk of kidney cancer among weight lifters was observed but became nonsignificant after adjusting for MVPA (Ptrend = 0.06), resulting in an HR of 0.94 (95% CI, 0.78–1.12) for low weight lifting and 0.80 (95% CI, 0.59–1.11) for high weight lifting. Conclusions Participants who engaged in weight lifting had a significantly lower risk of colon cancer and a trend toward a lower risk of kidney cancer than participants who did not weight lift.

Trends in Step-determined Physical Activity among Japanese Adults from 1995 to 2016 Purpose We tried to clarify the trends in step-determined physical activity (PA) among Japanese adults from 1995 to 2016. Methods Raw data from the National Health and Nutrition Surveys Japan (NHNS-J) performed between 1995 and 2016 were used, in compliance with the Statistics Act of Japan. NHNS-J was conducted annually by the Japanese government (the Ministry of Health, Labour, and Welfare) using a representative Japanese sample, with the same sampling method every year except in 2012 and 2016. A 1-d pedometer survey was conducted each year as a part of the NHNS-J, on a weekday in November specified by each individual. Because of the difference in age distribution of the samples, age-adjusted mean steps per day were calculated from 1995 to 2016 by sex. The time trends of step-determined PA levels among Japanese adults were described and examined using Joinpoint regression. Results The highest age-adjusted mean number of steps for men was 8235 steps per day in 2000, whereas it was 7667 steps per day in 2015. The highest age-adjusted mean numbers of steps for women were 7474 steps per day in 1998 and 6691 steps per day in 2015. The age-adjusted step-determined PA trend showed significantly decreasing trend from 1997 to 2008 in men (annual percentage change, −0.74; P < 0.001) and from 1998 to 2008 (annual percentage change, −1.30; P < 0.001) in women, by Joinpoint regression. Conclusion The age-adjusted step-determined PA among Japanese adults between 1995 and 2016 decreased from around 1997 to 1998 until around 2008, but since then, the decreasing trend became unclear both in men and in women. Continuous monitoring of PA trends is essential to assess the effectiveness of policies.

Obesity Prevalence and Musculoskeletal Injury History in Probation Officers Purpose The purpose of the present investigation was to identify 1) the prevalence of overweight and obesity and 2) factors associated with previous work-related musculoskeletal injury, and physical activity (PA) levels in North Carolina probation officers. Methods North Carolina probation officers (N = 1866) were sent a questionnaire on demographics, work history, injury history, and PA. A multivariable logistic regression model estimated the odds of reporting work-related musculoskeletal injury history within the past year, and multivariable ordinal logistic regression estimated the odds of reporting lower PA levels in the previous month. Odds ratios (OR) with 95% confidence intervals (CI) excluding 1.00 were deemed significant. Results Complete data were available for 1323 probation officers (70.9% completion rate; 46.5% female; mean ± SD age, 39.9 ± 10.0 yr). Officers that were classified as overweight and obese were 80.8% (body mass index [BMI] ≥ 25 kg·m−2), with 49.9% and 9.5% categorized as obese (BMI ≥ 30 kg·m−2) and severely obese (BMI ≥ 40 kg·m−2), respectively. Being older (1-yr increase; OR, 1.06; 95% CI, 1.04–1.09) and severely obese (compared to normally weighted; OR, 2.56; 95% CI, 1.19–5.51) was associated with a greater odds of sustaining a work-related musculoskeletal injury in the past year. A higher number of years of employment (1-yr increase; OR, 1.03; 95% CI, 1.01–1.04), being overweight or obese (compared to normal weight; OR, 1.57–3.22) and being female (compared with male: OR, 0.38; 95% CI, 0.31–0.47) was associated with the greater odds of lower PA levels in the previous month. Conclusions The prevalence of obesity is alarmingly high in probation officers, and is associated with a greater likelihood of sustaining previous work-related musculoskeletal injury and engaging in lower amounts of PA. Public safety administrators may consider worksite exercise/diet interventions and annual physical employment standards to combat obesity.

Resistance Training Induces Antiatherogenic Effects on Metabolomic Pathways Introduction Arising evidence suggests that resistance training has the potential to induce beneficial modulation of biomarker profile. To date, however, only immediate responses to resistance training have been investigated using high-throughput metabolomics whereas the effects of chronic resistance training on biomarker profile have not been studied in detail. Methods A total of 86 recreationally active healthy men without previous systematic resistance training background were allocated into (i) a resistance training (RT) group (n = 68; age, 33 ± 7 yr; body mass index, 28 ± 3 kg·m−2) and (ii) a non-RT group (n = 18; age, 31 ± 4 yr; body mass index, 27 ± 3 kg·m−2). Blood samples were collected at baseline (PRE), after 4 wk (POST-4wk), and after 16 wk of resistance training intervention (POST-16wk), as well as baseline and after the non-RT period (20–24 wk). Nuclear magnetic resonance–metabolome platform was used to determine metabolomic responses to chronic resistance training. Results Overall, the resistance training intervention resulted in favorable alterations (P < 0.05) in body composition with increased levels of lean mass (~2.8%), decreased levels of android (~9.6%), and total fat mass (~7.5%). These changes in body composition were accompanied by antiatherogenic alterations in serum metabolome profile (false discovery rate < 0.05) as reductions in non–high-density lipoprotein cholesterol (e.g., free cholesterol, remnant cholesterol, intermediate-density lipoprotein cholesterols, low-density lipoprotein cholesterols) and related apolipoprotein B, and increments in conjugated linoleic fatty acids levels were observed. Individuals with the poorest baseline status (i.e., body composition, metabolome profile) benefitted the most from the resistance training intervention. Conclusions In conclusion, resistance training improves cardiometabolic risk factors and serum metabolome even in previously healthy young men. Thus, suggesting attenuated risk for future cardiovascular disease.