Baseline Aerobic Fitness Research Articles

The effect of a pre- and post-operative exercise program versus standard care on physical activity and sedentary behavior of patients with esophageal and gastric cancer undergoing neoadjuvant treatment prior to surgery (the PERIOP-OG Trial): a randomized controlled trial†.

Neoadjuvant cancer treatment (NCT) reduces both physical fitness and physical activity (PA) levels, which can increase the risk of adverse outcomes in cancer patients. This study aims to determine the effect of exercise prehabilitation on PA and sedentary behavior (SB) in patients undergoing NCT and surgery for esophagogastric malignancies. This study is a randomized pragmatic controlled multi-center trial conducted across three Irish hospitals. Participants were aged ≥18 years scheduled for esophagectomy or gastrectomy and were planned for NCT and surgery. Participants were randomized to an exercise prehabilitation group (EX) that commenced following cancer diagnosis, continued to the point of surgery, and resumed following recovery from surgery for 6weeks or to usual care (UC) who received routine treatment. The primary outcome measures were PA and SB. Between March 2019 and December 2020, 71 participants were recruited: EX (n = 36) or UC (n = 35). No significant differences were found between the EX group and UC group on levels of PA or SBs across all measured timepoints. Significant decreases in moderate-vigorous physical activity levels (MVPAs) were found between baseline and post-surgery (P = 0.028), pre-surgery and post-surgery (P = 0.001) and pre-surgery and 6-week follow-up (P = 0.022) for all participants. Step count also significantly decreased between pre-surgery and post-surgery (P < 0.001). Baseline aerobic fitness was positively associated to PA levels and negatively associated with SB. Esophagogastric cancer patients have lower than recommended levels of PA at the time of diagnosis and this decreased further following completion of NCT. An optional home- or group-based exercise intervention was not effective in improving PA levels or behaviors across the cancer treatment journey.

Exercise is associated with younger methylome and transcriptome profiles in human skeletal muscle.

Exercise training prevents age-related decline in muscle function. Targeting epigenetic aging is a promising actionable mechanism and late-life exercise mitigates epigenetic aging in rodent muscle. Whether exercise training can decelerate, or reverse epigenetic aging in humans is unknown. Here, we performed a powerful meta-analysis of the methylome and transcriptome of an unprecedented number of human skeletal muscle samples (n = 3176). We show that: (1) individuals with higher baseline aerobic fitness have younger epigenetic and transcriptomic profiles, (2) exercise training leads to significant shifts of epigenetic and transcriptomic patterns toward a younger profile, and (3) muscle disuse "ages" the transcriptome. Higher fitness levels were associated with attenuated differential methylation and transcription during aging. Furthermore, both epigenetic and transcriptomic profiles shifted toward a younger state after exercise training interventions, while the transcriptome shifted toward an older state after forced muscle disuse. We demonstrate that exercise training targets many of the age-related transcripts and DNA methylation loci to maintain younger methylome and transcriptome profiles, specifically in genes related to muscle structure, metabolism, and mitochondrial function. Our comprehensive analysis will inform future studies aiming to identify the best combination of therapeutics and exercise regimes to optimize longevity.

Impairment in maximal lactate steady state after carbon monoxide inhalation is related to training status.

What is the central question of this study? What is the effect of an elevated carboxyhaemoglobin (COHb) concentration following carbon monoxide inhalation on the maximal lactate steady state (MLSS) in humans and is this effect dependent on aerobic fitness? What is the main finding and its importance? An elevated COHb concentration intensified physiological responses to exercise at the MLSS - including heart rate, ventilation and peripheral fatigue - in general and reduced the MLSS (i.e., destabilized the blood lactate concentration) in trained but not untrained males and females. This study investigated whether a lower effective [Hb], induced by carbon monoxide (CO) inhalation, reduces the peak oxygen uptake ( ) and the maximal lactate steady state (MLSS) and whether training status explains individual variation in these impairments. Healthy young participants completed two ramp incremental tests (n=20, 10 female) and two trials at MLSS (n=16, eight female) following CO rebreathe tests and sham procedures (SHAM) in random orders. All fitness variables were normalized to fat-free mass (FFM) to account for sex-related differences in body composition, and males and females were matched for aerobic fitness. The (mean (SD): -4.2 (3.7)%), peak power output (PPO) (-3.3 (2.2)%) and respiratory compensation point (RCP) (-6.3 (4.5)%) were reduced in CO compared with SHAM (P<0.001 for all), but the gas exchange threshold (-3.3 (7.1)%) was not (P=0.077). Decreases in (r =-0.45; P=0.047) and PPO (r=-0.49; P=0.029) in CO were correlated with baseline aerobic fitness. Compared to SHAM, physiological and perceptual indicators of exercise-related stress were exacerbated by CO while cycling at MLSS. Notably, the mean blood lactate concentration ([La]) increased (i.e., Δ[La]>1.0mM) between 10min (5.5 (1.4) mM) and 30min (6.8 (1.3) mM; P=0.026) in CO, with 9/16 participants classified as unstable. These unstable participants had a higher (66.2 (8.5) vs. 56.4 (8.8) mlkg FFM-1 min-1 , P=0.042) and at MLSS (55.8 (7.0) vs. 44.3 (7.0) mlkg FFM-1 min-1 , P=0.006) compared to the stable group. In conclusion, a reduced O2 -carrying capacity decreased maximal and submaximal exercise performance, with higher aerobic fitness associated with greater impairments in both.

Baseline Aerobic Fitness in High School and College Football Players: Critical for Prescribing Safe Exercise Regimens

Nontraumatic fatalities occur on a regular basis in high school (HS) and college football athletes, primarily in obese linemen performing high-intensity exercise. One contributing factor to these deaths may be a mismatch between baseline aerobic (cardiorespiratory) fitness and exercise regimens. There is a wide range of aerobic fitness in HS and college football players. Body mass index (BMI) is a safe and simple method for estimating baseline aerobic fitness. Retrospective cohort study. Level 3. A retrospective review was performed on 79 HS football athletes who had VO2Peak (mL·kg-1·min-1) measured during the offseason. Multivariate regression analysis was used to determine if BMI (obese, overweight, and normal; kg/m2), position played (linemen vs other), year in school (freshmen vs other), and/or race (African American vs White) were risk factors for poor aerobic fitness. A separate cohort of 135 (48 HS; 87 college) football athletes performed a 6-minute run test to determine speed (miles/min), extrapolate VO2Max, and calculate reference values for suggested upper threshold safe starting speeds (85% of maximum) for aerobic training based on BMI. The relationship between BMI and VO2Peak was assessed. The exercise regimens (speeds) of 2 collegiate football fatalities from the public domain were used to predict their VO2Max values. Mean VO2Peak (mL·kg-1·min-1) was 38.5 ± 8.6 (range 19.1-60.6); when grouped by BMI, low scores (<40) were found in 87.5% of obese (32.4 ± 7.7), 47.8% of overweight (40.8 ± 7.6), and 45.2% of normal (41.4 ± 7.8) athletes. VO2Peak was significantly lower in linemen (32.8 ± 6.4; P = 0.007) compared with nonlineman (41.8 ± 7.9), and in obese players (by BMI; 32.4; P = 0.019) compared with nonobese players (41.4 ± 7.6), but did not differ by age, year in school, or race. Means for speed (min/mile) and extrapolated VO2Max (mL·kg-1·min-1) for the 6-minute run test by BMI groups were both significantly different (P = 0.001) for normal (7.0 ± 0.6; 51.1 ± 2.6), overweight (7.6 ± 0.8; 46.5 ± 3.2), and obese (8.9 ± 1.5; 36.8 ± 5.9) athletes. There was a significant negative correlation (r = -0.551; P = 0.001; R2 = 0.304) between VO2Peak and BMI. Safe starting speed recommendations for running 1 mile range from 7.3 to 12.1 min/mile for BMIs 20 to 40 kg/m2 for HS and college athletes. For the 2 fatalities (mean, BMI of 36.5 kg/m2) repetitive sprint speeds were 49 and 89% higher than our safe starting speeds for their BMI. A large spectrum of baseline aerobic fitness was noted in HS and college football players. Obese players and linemen had statistically lower baseline aerobic fitness, a major risk factor for possible heat illness. BMI is an acceptable surrogate for VO2Peak and can be employed to develop safe training regimens without the need for a maximum fitness test, which can place the athlete at risk for a medical event. Knowledge of BMI provides an estimate of baseline aerobic fitness and a foundation for prescribing safe, individualized exercise regimens.

Higher Baseline Aerobic Fitness Influences Jumping Performance During Military Operational Stress

Vertical jump (VJ) testing via force plate technology serves as a field-expedient indicator of fatigue and readiness in the military. PURPOSE: To determine if higher baseline aerobic fitness is protective against declining unloaded and loaded jump performance during simulated military operational stress (SMOS). METHODS: Eighteen military men (27 ± 6 y, 84.4 ± 12.7 kg, 177.8 ± 7.6 cm) completed a 5-day SMOS protocol characterized by frequent cognitive testing, marksmanship assessments, and a ~ 90 min Tactical Mobility Test (TMT) daily. The schedule was the same each day except that subjects had four instead of eight hours of sleep and 50% instead of 100% of their caloric needs on days 2-3. Participants performed VJ testing in unloaded (UL) and loaded (LD) (16-kg) conditions at three time points during the TMT: 1) pre, 2) following 2-min water can carry, fire and movement, casualty drag, and 300-m shuttle runs (UL and LD, 16-kg) (mid), and 3) after a 4-mile ruck march (post). Subjects were divided into groups using a median split based on baseline VO2peak (HIGH vs. LOW) assessments. Three-way ANOVAs for UL and LD conditions were used to examine the effect of group*time*day on jump height (JH). RESULTS: The three-way interactions were not statistically significant. A significant group*day interaction was observed for UL condition JH (p = .035). The main effect of day from the simple two-way ANOVA was not statistically significant at each level of group (HIGH: p = .111, np2 = .218; LOW p = .312, np2 = .132), but this effect was in opposite directions. Adjusted means on days 1 to 4 declined for LOW (M: 24.7 cm, SE: 2.0 to M: 22.9 cm, SE: 1.9) but increased for HIGH (M: 27.1 cm, SE: 1.2 to M: 28.9 cm, SE: 1.3). In the LD condition, no significant interactions were observed, but there was a significant main effect of time (p = .001). For the LD condition, pre-JH (M: 21.1 cm, SE: 1.0) was significantly higher than mid-JH (M: 19.1 cm, SE: 1.1, p = .001) and post-JH (M: 19.6 cm, SE: 1.0, p = .031). CONCLUSION: We demonstrate that higher levels of aerobic fitness was protective against declining JH performance in the UL, but not LD, condition across acute SMOS, suggesting that other factors (e.g., strength/power) may be important for maintaining jump performance in the LD condition. Funded by the Department of Defense (Award # W81XWH-17-2-0070).

Can Physiological and Psychological Factors Predict Dropout from Intense 10-Day Winter Military Survival Training?

Background: In the military context, high levels of physiological and psychological stress together can compromise individual’s ability to complete given duty or mission and increase dropout rates. The purpose of this study was to investigate if baseline physical fitness, body composition, hormonal and psychological factors could predict dropout from a 10-day intense winter military survival training. Methods: 69 conscripts volunteered to participate in the study. Physical fitness (muscle strength and power, muscle endurance, and aerobic fitness), body composition and hormonal variables (BDNF, testosterone, cortisol, SHBG, DHEAS, IGF-1) together with self-reported psychological factors (short five personality, hardiness, sense of coherence, stress, depression) were assessed prior the survival training. Results: During the survival training, 20 conscripts (29%) dropped out. Baseline aerobic fitness (hazard ratio, HR: 0.997, 95% CI: 0.994–0.999, p = 0.006) and serum cortisol (HR: 1.0006, 95% CI: 1.001–1.011, p = 0.017) predicted dropout in Cox regression model. Each 10 m increase in the 12 min running test decreased the risk for dropout by 3%. Conclusion: Although most of the physiological and psychological variables at the baseline did not predict dropout during a short-term winter survival military training, baseline information of aerobic fitness and serum cortisol concentration may be useful to target support for individuals at higher potential risk for dropout.

Response heterogeneity in fitness, mobility and cognition with exercise-training in MS.

Exercise-training is a beneficial approach for improving function in persons with multiple sclerosis (MS). However, it is unlikely that every participant who engages in an exercise-training intervention will demonstrate similar benefits. Identifying factors that may influence the accrual of specific exercise-training benefits can aid in the development of optimized rehabilitation interventions for improving specific outcomes in MS. This study described possible response heterogeneity in physical fitness, mobility and cognitive outcomes with exercise-training and identified baseline performance, compliance and demographic/clinical outcomes as possible predictors of exercise-related changes in those outcomes. Thirty-two persons with MS-related mobility disability completed 6-months of multimodal exercise-training. Physical fitness, mobility and cognitive processing speed (CPS) were measured before and after the 6months. There was response heterogeneity in fitness, mobility and cognitive outcomes with multimodal exercise-training. Low baseline aerobic fitness, slow walking speed and slow CPS were associated with greater exercise-related improvements in those respective outcomes. Those with MS-related mobility disability who have the lowest aerobic fitness, walking speed and CPS might benefit the most from multimodal exercise-training. This provides critical evidence for informing the development of a precision medicine framework for improving targeted outcomes with exercise-training in MS.

Targeting Exercise Interventions to Patients With Cancer in Need: An Individual Patient Data Meta-Analysis.

Exercise effects in cancer patients often appear modest, possibly because interventions rarely target patients most in need. This study investigated the moderator effects of baseline values on the exercise outcomes of fatigue, aerobic fitness, muscle strength, quality of life (QoL), and self-reported physical function (PF) in cancer patients during and post-treatment. Individual patient data from 34 randomized exercise trials (n = 4519) were pooled. Linear mixed-effect models were used to study moderator effects of baseline values on exercise intervention outcomes and to determine whether these moderator effects differed by intervention timing (during vs post-treatment). All statistical tests were two-sided. Moderator effects of baseline fatigue and PF were consistent across intervention timing, with greater effects in patients with worse fatigue (Pinteraction = .05) and worse PF (Pinteraction = .003). Moderator effects of baseline aerobic fitness, muscle strength, and QoL differed by intervention timing. During treatment, effects on aerobic fitness were greater for patients with better baseline aerobic fitness (Pinteraction = .002). Post-treatment, effects on upper (Pinteraction < .001) and lower (Pinteraction = .01) body muscle strength and QoL (Pinteraction < .001) were greater in patients with worse baseline values. Although exercise should be encouraged for most cancer patients during and post-treatments, targeting specific subgroups may be especially beneficial and cost effective. For fatigue and PF, interventions during and post-treatment should target patients with high fatigue and low PF. During treatment, patients experience benefit for muscle strength and QoL regardless of baseline values; however, only patients with low baseline values benefit post-treatment. For aerobic fitness, patients with low baseline values do not appear to benefit from exercise during treatment.

Physical deconditioning is the common denominator in both obese and overweight subjects with nonalcoholic steatohepatitis.

Obesity and decreased physical activity mirror increasing prevalence of nonalcoholic fatty liver disease (NAFLD). We aimed to investigate associations between aerobic fitness, anthropometrics and disease parameters in patients with nonalcoholic steatohepatitis (NASH). We hypothesised that NASH subjects have lower aerobic power and capacity than untrained, sedentary, normal subjects. Forty subjects (60% obese, 40% overweight) with biopsy-confirmed NASH and NAFLD activity score (NAS) ≥4 were enrolled in a clinical trial where anthropometrics, laboratories, liver fat content by MRI, activity, and aerobic fitness by cycle ergometry data were obtained. NASH subjects were significantly deconditioned compared to 148 untrained, sedentary, healthy subjects from our laboratory in aerobic power (VO2peak) (NASH 16.8±6.6 vs control 28.4±10.6mL/kg/min, P<0.0001) and capacity (VO2 at lactate threshold [LT]) (NASH 8.3±2.5 vs control 14.1±5.9mL/kg/min, P<0.0001). NASH subjects' fitness was comparable to the "least fit" tertile of controls: VO2peak [NASH 16.8±6.6 vs "least fit" 17.3±3.3, P=0.64]) and VO2 at LT (NASH 8.3±2.5 vs "least fit" 9.3±2.1, P=0.31). Fitness was similar in obese compared to overweight subjects (adjusted for gender) and was not correlated with visceral adiposity or NAS. Engaging in dedicated cardiovascular activity correlated with higher VO2peak and VO2peak at LT. Aerobic deconditioning was universally present in NASH subjects. NASH subjects' fitness was similar to our laboratory's "least fit" untrained, sedentary control subjects. Further research investigating NASH patients' ability to improve low baseline aerobic fitness is warranted.

Comparing the Transfer Effects of Simultaneously and Sequentially Combined Aerobic Exercise and Cognitive Training in Older Adults

It is known that both cognitive training and aerobic exercise training can independently improve cognitive performance in older adults. Combined multimodality (cognitive and aerobic) training has shown promise in producing significantly more training gains in older adults than pure physical exercise and control; however, results are mixed. To address these mixed results and elucidate the efficacy of different schedules of multimodal training, we compared simultaneous and sequential formats. To this end, 42 older adults (M = 68.05 years) participated in 12 sessions of same-day multimodal training and were randomly assigned to either the simultaneous (concurrent cognitive dual-task and aerobic exercise) or sequential training group (cognitive dual-task followed by aerobic exercise). Both groups showed significant improvement on measures of processing speed and verbal memory following training, with the sequential group showing a significant training advantage on working memory. Motivation to engage in cognitive effort moderated the training gains in verbal memory, and baseline aerobic fitness moderated the magnitude of training gains in response inhibition negatively. The current findings demonstrate the selective effects of training format on cognitive outcomes, in line with the principle of neural overlap, which suggests that improvements should occur to the extent that the trained and untrained tasks share underlying neural pathways. The results also underscore the importance of considering individual difference factors in cognitive training studies.

Description and Rate of Musculoskeletal Injuries in Air Force Basic Military Trainees, 2012-2014.

Musculoskeletal injuries are common in military trainees and have significant medical and operational effects. To provide current musculoskeletal injury epidemiology data for US Air Force basic military trainees. Descriptive epidemiologic study with cross-sectional features. US Air Force Basic Military Training, Joint Base San Antonio-Lackland, Texas. All recruits who entered training between July 1, 2012, and June 30, 2014. Incidence density rate of all musculoskeletal injuries (stratified by body region and type) and factors and costs associated with injuries. Of the 67 525 trainees, 12.5% sustained 1 or more musculoskeletal injuries. The overall incidence density rate was 18.3 injuries per 1000 person-weeks (15.1 for men and 29.4 for women). The most common diagnosis (n = 2984) was Pain in joint, lower leg, as described in the International Classification of Diseases, Ninth Revision, Clinical Modification, code 719.46. Injuries were more common among those with lower levels of baseline aerobic and muscular fitness. Injured trainees were 3.01 times (95% confidence interval = 2.85, 3.18) as likely to be discharged, and injured trainees who did graduate were 2.88 times (95% confidence interval = 2.72, 3.04) as likely to graduate late. During the surveillance period, injuries resulted in more than $43.7 million in medical ($8.7 million) and nonmedical ($35 million) costs. Musculoskeletal injuries, predominantly of the lower extremities, have significant fiscal and operational effects on Air Force Basic Military Training. Further research into prevention and early rehabilitation of these injuries in military trainees is warranted.

Is baseline aerobic fitness associated with illness and attrition rate in military training?

BackgroundRespiratory illnesses are a leading cause of morbidity and medical discharge in the military. This study aimed to investigate the effects of baseline aerobic fitness on haematological, salivary and mood...

Abstract MP66: AREST Lifestyle: Adherence Effects of a Comprehensive Reminder System on Exercise Adherence in Post-Myocardial Infarction Patients

Background: The risk of recurrent cardiac events can be reduced by 30-50% through regular, structured exercise; however, there remains a high rate of inactivity in post myocardial infarction (MI) patients. Forgetting to exercise may be a contributor to inactivity. This study assessed the hypothesis that text message reminders may be an effective strategy to reduce forgetfulness and inactivity. Methods: In this one year, single center study, we recruited 50 cardiac rehabilitation patients within 2 weeks of their MI. Participants were randomized to usual care or to receive text message reminders 4 times daily which stated "Please remember to exercise 45 minutes today". The outcomes measured were the frequency and total duration of exercise (assessed by log books) and physical endurance/ aerobic fitness (assessed by exercise stress testing at months 1, 3 and 12). Results: Intervention and control patients had similar baseline characteristics with an average age of 64. In the control group, monthly duration of exercise fell from an average of 683 minutes over 17 days at month 1 to 416 minutes over 11 days at month 12. Patients randomized to text message reminders exercised 772 minutes over 18 days at month 1 and 794 minutes over 18 days in month 12 (p&lt;0.01 for duration of exercise, control versus intervention, month 12). Baseline aerobic fitness and cardiac endurance was similar between control and intervention groups. However, there was a significant improvement in aerobic fitness and cardiac endurance at month 12 with text reminders (7.4 versus 6.1 METS achieved month 12, p&lt;0.01). In all sub-groups analyzed this intervention significantly improved exercise adherence and fitness. Conclusions: In summary, this system improved frequency and duration of exercise, and objective measures of cardiac endurance and aerobic fitness. While this study was not designed to assess clinical outcomes, this text message reminder system represents a simple and scalable method for improving adherence to exercise regimens among post-MI patients.

Heat acclimation increases arterial elasticity in young men

The major physiological adaptations that occur during heat acclimation (HA) are well documented. However, no studies have provided compelling evidence about the effect of HA on arterial elastic properties. The aim of this study was to examine the changes in large artery elasticity (LAE) and small artery elasticity (SAE) concomitant with HA and to determine the potential relationships among changes in arterial elasticity, baseline aerobic fitness level, and improvement in endurance capacity (EC). During 10-day HA, the subjects (n = 21) exercised daily on a treadmill for 110 min at an intensity of 55%-60% of peak oxygen uptake in a climatic chamber preset to 42 °C and 18% relative humidity. EC was tested in the heat before and after HA. Arterial elasticity was assessed by diastolic pulse wave analysis (HDI/Pulse Wave CR-2000) at baseline and after HA. Blood samples were drawn at baseline. After HA, there was a 17% increase in LAE (from 21.19 ± 4.72 mL·mm Hg(-1) × 10 to 24.77 ± 5.91 mL·mm Hg(-1) × 10, p < 0.05) and an 18% increase in SAE (from 9.32 ± 1.76 mL·mm Hg(-1) × 100 to 10.98 ± 1.75 mL·mm Hg(-1) × 100, p < 0.01). EC increased by 86% (from 88.62 ± 27.51 min to 161.95 ± 47.80 min, p < 0.001) as a result of HA. No significant associations were revealed between changes in arterial elasticity parameters and improvement in EC or baseline aerobic fitness level. We demonstrated, for the first time, that HA has a positive impact on the parameters of arterial elasticity. Further investigations are needed to determine the mechanisms underlying these changes and the potential relationships among arterial elasticity, aerobic fitness level, and EC.

Relationship of aerobic fitness and motor skills with memory and attention in preschoolers (Ballabeina): A cross-sectional and longitudinal study

BackgroundThe debate about a possible relationship between aerobic fitness and motor skills with cognitive development in children has recently re-emerged, because of the decrease in children's aerobic fitness and the concomitant pressure of schools to enhance cognitive performance. As the literature in young children is scarce, we examined the cross-sectional and longitudinal relationship of aerobic fitness and motor skills with spatial working memory and attention in preschool children.MethodsData from 245 ethnically diverse preschool children (mean age: 5.2 (0.6) years, girls: 49.4%) analyzed at baseline and 9 months later. Assessments included aerobic fitness (20 m shuttle run) and motor skills with agility (obstacle course) and dynamic balance (balance beam). Cognitive parameters included spatial working memory (IDS) and attention (KHV-VK). All analyses were adjusted for age, sex, BMI, migration status, parental education, native language and linguistic region. Longitudinal analyses were additionally adjusted for the respective baseline value.ResultsIn the cross-sectional analysis, aerobic fitness was associated with better attention (r = 0.16, p = 0.03). A shorter time in the agility test was independently associated with a better performance both in working memory (r = -0.17, p = 0.01) and in attention (r = -0.20, p = 0.01). In the longitudinal analyses, baseline aerobic fitness was independently related to improvements in attention (r = 0.16, p = 0.03), while baseline dynamic balance was associated with improvements in working memory (r = 0.15, p = 0.04).ConclusionsIn young children, higher baseline aerobic fitness and motor skills were related to a better spatial working memory and/or attention at baseline, and to some extent also to their future improvements over the following 9 months.Trial Registrationclinicaltrials.gov NCT00674544

How Much Structured Physical Activity Do Non-Amish Adults Need in Order to Meet the Activity Level of Amish Adults?

The Amish have low rates of obesity and cardiovascular disease risk factors, which has been attributed to their active lifestyles. How this activity level relates to non-agrarian workers is unknown. PURPOSE: To determine how much structured physical activity non-Amish adults need in order to equal activity levels of Amish adults. METHODS: Twenty adults (18 to 65 years) completed the Rockport One-Mile Walk Test to assess baseline aerobic fitness. To assess baseline physical activity levels, each subject wore a pedometer during waking hours for one week. Daily logs were used to record total structured and unstructured steps/day and minutes/day of physical activity. The subsequent week, subjects were instructed to increase their activity as need in order to equal the reported steps/day of the Amish (>14,000 steps/day for females and >18,000 steps/day for males). RESULTS: Week 1 steps/day for males was 11,584 (7,444 unstructured/4,134 structured) and for females was 11,184 (6,733 unstructured/4,456 structured), respectively. During Week 2, males increased their total steps/day to 18,654 (7,510 unstructured/11,146 structured) and females increased total steps/day to 14,755 (6,611 unstructured/8,578 structured), respectively. In order to meet the target steps/day, males increased their structured exercise time from 43 to 116 and females from 39 to 73 minutes/day. CONCLUSION: In order to meet the physical activity levels of the Amish, non- Amish adults need to increase the amount of structured physical activity substantially.

The impact of aerobic fitness on functioning in chronic back pain

Despite lack of convincing evidence that reduced aerobic fitness is associated with chronic back pain (CBP), exercise programs are regarded as being effective for persons with non-specific CBP. It is unsure whether gain in aerobic fitness following intervention is associated with functioning improvement in persons with CBP. The objective of this prospective cohort study was to study the impact of aerobic fitness on functioning in persons with CBP, at baseline and following 3-week intensive interdisciplinary intervention. This study included persons who had passed 8 weeks of sick-listing because of back pain (n = 94) and were referred to a 3-week intensive biopsychosocial rehabilitation program. Aerobic fitness was assessed with a sub-maximal bicycle test at baseline, at admission to and discharge from the rehabilitation program, and at 6 months follow-up. Contextual factors, body function, activity and participation were evaluated before and after intervention. In addition, working ability was recorded at 3-years follow-up. At baseline aerobic fitness was reduced in most subjects, but improved significantly following intervention. Baseline measurements and intervention effects did not differ among the diagnostic sub-groups. Neither contextual factors nor functioning at baseline were associated with aerobic fitness. Increase in aerobic fitness was not associated with improvements in functioning and contextual factors and work-return following intervention either. From this study we conclude that improvement of aerobic fitness seems of limited value as goal of treatment outcome for patients with CBP.

Optimizing the therapeutic benefits of exercise in Type 2 diabetes

Other than diet and medication, exercise is considered one of the three cornerstones of good diabetes treatment. Nevertheless, current clinical guidelines on Type 2 diabetes provide no detailed information on the modalities of effective exercise intervention in the treatment of Type 2 diabetes. Based on a review of currently available literature, exercise modalities are being identified to maximize the benefits of exercise intervention in the treatment of different Type 2 diabetes subpopulations. Both endurance and resistance types of exercise have equal therapeutic strength to improve metabolic control in patients with Type 2 diabetes. When applying endurance-type exercise, energy expenditure should be equivalent to approximately 1.7-2.1 MJ/exercise bout on 3 but preferably 5 days/wk. In sarcopenic or severely deconditioned patients with Type 2 diabetes, focus should lie on the implementation of resistance-type exercise to attenuate and/or reverse the decline in skeletal muscle mass and strength. Before choosing the most appropriate exercise modalities, the patient's disease stage should be well characterized, and an ECG-stress test should be considered. Based on baseline aerobic fitness, level of co-morbidities, body composition, and muscle strength, patients should be provided with an individually tailored exercise intervention program to optimize therapeutic value. A multidisciplinary individualized approach and continued exercise training under personal supervision is essential to enhance compliance and allow long-term health benefits of an exercise intervention program.

Bicycle Versus Treadmill Maximal Graded Exercise Testing in Lean Versus Obese Children

The number of obese children has dramatically increased and the physical fitness level of children has decreased during the past decade. Maximal graded exercise tests (GXT) may provide valuable information concerning the baseline aerobic fitness and the effectiveness of intervention strategies to improve aerobic fitness in children. The optimal type of ergometry to use while conducting maximal GXT testing children, specifically in lean versus obese children, has not been fully elucidated. PURPOSE To compare VO2 peak measures from maximal GXT using treadmill and bicycle ergometry, in lean (BMI <85th percentile for age and sex) versus obese (BMI >95th percentile for age and sex) prepubescent (Tanner Maturation Stage ± 2) children ages 7 to 11 yrs. METHODS Maximal GXT were performed to determine VO2 peak measures using treadmill (TM) and bicycle (BK) ergometry, and body composition was determined using total body dual energy x-ray absorptiometry (DXA) scans in lean children (LC; n = 21) and obese children (OC; n = 20). Group mean VO2 peak comparisons were determined using two-way ANOVA with repeated measures. RESULTS Absolute peak VO2 (L) did not significantly differ between the lean and obese children for the TM GXT (1.21 ± 0.11 LC vs 1.49 ± 0.11 OC) or for the BK GXT (1.34 ± 0.08 LC vs 1.46 ± 0.08 OC). The LC had significantly greater (p <0.05) peak VO2 when expressed relative (ml/kg) to body weight for the TM GXT (37.0 ± 2.0 LC vs 23.4 ± 2.1 OC) and BK GXT (39.0 ± 1.7 LC vs 25.4 ± 1.8 OC), and for the BK GXT when expressed relative to fat-free mass (FFM; 50.2 ± 1.8 LC vs 42.6 ± 1.8 OC) but not for the TM GXT (44.2 ± 2.6 LC vs 43.0 ± 2.6 OC). The LC had significantly greater absolute peak VO2 for the Bike vs Tmill GXT (1.34 ± 0.08 BK vs 1.21 ± 0.11 TM) and significantly greater peak VO2 when expressed relative to FFM (50.2 ± 1.8 BK vs 44.2 ± 2.6 TM), but not when peak VO2 was expressed relative to body weight (39.0 ± 1.7 BK vs 37.0 ± 2.04 TM). The obese children had no significant differences between Bike and Tmill GXT measures when the peak VO2 was expressed as an absolute (1.46 ± 0.08 BK vs 1.49 ± 0.11 TM), relative to body weight (25.4 ± 1.8 BK vs 23.4 ± 2.1 TM), or relative to FFM (42.6 ± 1.8 BK vs 43.0 ± 2.6 TM). CONCLUSION Obesity status (lean vs obese) should be considered during the selection of ergometry type used during maximal GXT in prepubescent children. Supported by University of Kentucky Graduate Research Student Support Fund and the University of Kentucky Pediatric Exercise Physiology Laboratory

Predicting heart growth during puberty: The Muscatine Study.

During childhood, heart growth is closely associated with somatic growth including increases in body weight, fat-free body mass (FFM), and height. However, with age, greater variability in heart size in relationship to body size is observed, presumably attributable to the increased effect of cardiac workload. At this time, little is known as to what functional attributes (eg, aerobic fitness) contribute to cardiac workload and the relative contribution of these attributes to heart growth during childhood and adolescence. In this article, we report cross-sectional and longitudinal relationships among aerobic fitness, body size, blood pressure (BP), and left ventricular mass (LVM) through puberty including the predictors of heart growth during puberty and the tracking of LVM from pre-puberty to late and post-puberty. Describing the predictors of heart size and heart growth and establishing the likelihood that a large heart, relative to peers, may (or may not) remain a large heart should aid pediatricians in discerning between normal developmental increases in LVM and increases in LVM suggestive of excessive heart growth (left ventricular hypertrophy). Using a repeated-measures design, we assessed aerobic fitness, FFM, fatness, weight, height, sexual maturation, resting BP, peak exercise BP, and LVM in 125 healthy children (mean baseline age: 10.5 years) for a period of 5 years. All subjects were either in prepuberty or early puberty at the beginning of the study. At follow-up, 110 subjects attempted all research procedures (87% of the initial cohort). Using anthropometry and bioelectrical impedance, we measured FFM, fatness, weight, and height quarterly (once every 3 months) for a total of 20 examinations. Resting BP and LVM (2-dimensional echocardiography) were also assessed quarterly. Aerobic fitness, peak exercise BP, and sexual maturation (staging of secondary sex characteristics and, for boys, serum testosterone) were measured annually (5 examinations). The same field staff conducted all examinations. Statistical methods included Spearman rank correlation coefficients (r(s)) calculated to estimate how well the year 5 LVM was predicted by LVM at earlier years. We also categorized the LVM data into tertiles and reported the percentage who remained in the extreme tertiles in year 5, given they began in that tertile in year 1. Gender-specific stepwise multivariate analysis was used to evaluate predictors of follow-up LVM and predictors of changes in LVM. The latter model examined whether the variability in the changes in LVM, as quantified by subject-specific slopes, could be explained by changes in predictor variables, also quantified by subject-specific slopes. At baseline and at follow-up, boys tended to be taller, leaner, more aerobically fit, and had greater LVM than girls. Rate of change for these variables was also greater in boys than girls. For example, LVM increased 62% in boys and 48% in girls. At year 5, subjects had advanced at least 1 stage in genital or breast development and over 80% of the subjects were in late- or post-puberty. Significant and strong tracking of heart size (r(s) =.65-.87) was observed. The likelihood that a subject would be in an extreme tertile for heart size at follow-up was approximately doubled if he or she started there at baseline. In boys, baseline FFM explained 54% of the variability in follow-up LVM. Change in aerobic fitness and change in FFM explained 55% of the variability in change in LVM. In girls, baseline aerobic fitness and fatness explained 45% of the variability in follow-up LVM. Because FFM did not enter in this model, we constructed an alternative model in which baseline aerobic fitness adjusted for FFM was entered. Using this approach, 43% of the variability in follow-up LVM was explained by baseline FFM, fatness, and adjusted aerobic fitness. Change in FFM explained 58% of the variability in change in LVM. (ABSTRACT TRUNCATED)