RATIONALE: Cardiotoxicity is a troubling long-term side effect of chemotherapy cancer treatment, affecting therapy and quality of life (QOL). Exercise is beneficial in heart failure (HF) patients and in cancer survivors without HF, but has not been tested in cancer survivors with treatment induced HF. METHODS: We present case studies for two survivors: a 56-year old female Hodgkin's lymphoma survivor (Pt 1) and a 44-year old male leukemia survivor (Pt 2). We conducted a 16-week exercise program with the goal of 30 minutes of exercise performed 3 times per week at a minimum intensity of 50% heart rate reserve (HRR) or '12' rating of perceived exertion (RPE). RESULTS: Pt 1 improved from 11.5 minutes of exercise split over two bouts at an RPE of 14 to a 30 minute bout at an RPE of 15. Pt 2 improved from 11 minutes of exercise split over two bouts at an RPE of 12 to an 18 minute bout at an RPE of 12. Both improved in VO(2) peak (Pt 1: 13.9 to 14.3 mlO(2)/kg/min; Pt 2: 12.5 to 18.7 mlO(2)/kg/min). Ejection fraction increased for Pt 2 (25-30% to 35-40%) but not for Pt 1 (35-40%). QOL as assessed by the SF-36 Physical Component Scale (PCS) improved from 17.79 to 25.31 for Pt 1 and the Mental Component Scale (MCS) improved from 43.84 to 56.65 for Pt 1 and from 34.79 to 44.45 for Pt 2. CONCLUSIONS: Properly designed exercise interventions can improve physical functioning and quality of life for this growing group of survivors.
Most sport scientists still do not consider breathing to be a limiting factor for exercise performance. However, the past decade has seen evidence emerge showing unequivocally that breathing not only limits exercise performance, but that removal of this limitation improves performance. This review will describe the mechanisms by which respiratory muscle work limits exercise performance, as well as the evidence that specific training of the respiratory pump muscles improves performance in the context of both endurance and repeated sprint sports. Finally, the mechanisms underlying this ergogenic effect will be considered, as well as their implications for the practical application of respiratory muscle training.
The purpose of this study was to investigate the effect of single bouts of exercise on changes in ischemia-modified albumin (IMA). Twenty wrestlers (mean age, 28.8 ± 8.96 years) participated in this study. They performed a typical 1.5-hour wrestling training session. Blood was sampled before and immediately after training. The albumin-cobalt binding test was used to measure IMA levels. Serum albumin concentrations and blood lactate levels were also evaluated. Mean serum IMA levels were 0.281 ± 0.052 ABSU before training and 0.324 ± 0.039 ABSU after training. A single bout of acute exercise led to significant (p < 0.05) increases in IMA. The results of the correlation tests indicated that there was a positive correlation between IMA and lactate levels (r = 0.873; p < 0.001). There were no significant correlations between IMA and albumin (r = −0.058; p = 0.807), and between albumin and lactate levels (r = −0.120; p = 0.613). Our results showed that demanding, intense anaerobic physical activity might influence the generation of IMA.
The aim of this study was to investigate the influence of IL-10 gene polymorphisms on URTI incidence.
To this end, one hundred healthy elite male athletes participating in the study were classified as either healthy or prone to frequent URTI. Blood samples and DNA isolation, multiplex PCR, and Taqman real-time PCR were carried out. Genomic DNA was extracted from peripheral leukocytes of whole blood samples using the QIAmp DNA Blood Mini Kit (Qiagen, Hilden, Germany). For comparison of the distribution of genotypes between two groups and for estimating odds ratios (OR) for URTI susceptibility in relation to the IL-10 polymorphism, Pearson's chi-square and Logistic regression method were used respectively.
The IL-10-1082 genotype distribution differed between athletes with URTI and healthy athletes (χ2=8. 14, P=0.017). The IL-10 high-expression genotype (GG), relative to the other two genotypes combined (AG + AA), was associated with a tendency for an increased likelihood of frequent URTI (OR: 4. 63, 95% CI: 1. 58-21. 53; P=0. 033).
In conclusion, findings from this study have identified a potential role of genetic variation in influencing the risk for URTI in athletic populations and SNPs in the IL-10 genes were associated with an altered risk profile. These measures may have a predictive value in the identiﬁcation of individuals who are more likely to experience recurrent infections when exposed to high physical stress in the areas of athletic endeavor.
This study was aimed at examining the associations between health disparities and physical activity, and their contributions to health and academic problems in schoolchildren.
Pertinent data from a community-wide survey were analyzed, which included 2930 households with schoolchildren aged 7–14 years. Associations between the parents' self-reported race/ethnicity, parental education, household income, children's health status, physical activity, and academic problems were determined by Chi-square and logistic regression analyses. Contributory factors for children's health status, physical activity, and academic problems were predicted by logistic regression fitting.
Within white/Caucasian children, 86.0% had very good/excellent health and 77.9% were physically active, values higher than those in Latino/Hispanic (77.8%, p < 0.0001 and 71.9%, p = 0.0030) and black/African American children (80.0%, p = 0.0409 and 73.1%, p = 0.0973). White schoolchildren were less likely to have academic problems (8.9%) than Latino (12.5%, p = 0.0256) or black (26.1%, p < 0.0001) schoolchildren. Health status was reciprocally (p < 0.0001) inter-related to physical activity and was the most significant factor (p < 0.0001) associated with academic problems.
Children's health status determined by both healthy lifestyles and sociodemographic factors is the most significant contributory factor associated with academic problems. Physical activity should be considered as an intervention to reduce health disparities and academic problems among schoolchildren.
Older types of pedometers had varied levels of accuracy, which ranged from 0% to 45%. In addition, to obtain accurate results, it was also necessary to position them in a certain way. By contrast, newer models can be placed anywhere on the body; however, their accuracy is unknown when they are placed at different body sites. We determined the accuracy of various newer pedometers under controlled laboratory and free walking conditions. A total of 40 participants, who varied widely in age and body mass index, were recruited for the study. The numbers of steps recorded using five different pedometers placed at the waist, the chest, in a pocket, and on an armband were compared against those counted with a hand tally counter. With the exception of one, all the pedometers were accurate at moderate walking speeds, irrespective of their placement on the body. However, the accuracy tended to decrease at slower and faster walking speeds, especially when the pedometers were worn in the pockets or kept in the purse (p < 0.05). In conclusion, most pedometers examined were accurate when they were placed at the waist, chest, and armband irrespective of the walking speed or terrain. However, some pedometers had reduced accuracy when they were kept in a pocket or placed in a purse, especially at a slower and faster walking speeds.
Interleukin-6 (IL-6) is a pleiotropic cytokine secreted by many different cell types, and skeletal muscle is an important source of IL-6 during exercise. Here, we studied the effects of glucose deprivation in vitro on skeletal muscle-derived IL-6 expression and release in C2C12 myocytes, as well as its regulation by p38 mitogen-activated protein kinase (p38MAPK) and reactive oxygen species (ROS). C2C12 myotubes were cultured in DMEM medium containing 4.5 g · L−1 glucose (glucose control, GC) or DMEM medium containing no glucose (glucose deprivation, GD) for 0, 6, 12, 18 and 24 hours, and then incubated with 10mM NAC (a ROS scavenger) or 10 μM SB203580 (a p38MAPK inhibitor) under either GC or GD conditions for 24 hours. IL-6 expression levels were subsequently analyzed using RT–PCR, and IL-6 protein levels in the medium were measured using ELISA. Glucose deprivation significantly enhanced IL-6 expression at 18 and 24 hours compared to the glucose control, and caused IL-6 protein levels to increase significantly over the entire 24-hour measurement period. The ROS scavenger NAC inhibited the glucose deprivation-induced release of IL-6 protein almost completely, while the p38MAPK inhibitor SB203580 inhibited glucose deprivation-induced IL-6 protein release to a lesser extent. Our study suggests that glucose deprivation in C2C12 myocytes induces IL-6 expression and release, and that this IL-6 release is mainly mediated via ROS signaling. Skeletal muscle-derived IL-6 may thus play an important role in energy metabolism during exercise.
The epidemic of obesity is impacting an increasing proportion of children, adolescents and adults with a common feature being low levels of physical activity (PA). Despite having more knowledge than ever before about the benefits of PA for health and the growth and development of youngsters, we are only paying lip-service to the development of motor skills in children. Fun, enjoyment and basic skills are the essential underpinnings of meaningful participation in PA. A concurrent problem is the reported increase in sitting time with the most common sedentary behaviors being TV viewing and other screen-based games. Limitations of time have contributed to a displacement of active behaviors with inactive pursuits, which has contributed to reductions in activity energy expenditure. To redress the energy imbalance in overweight and obese children, we urgently need out-of-the-box multisectoral solutions. There is little to be gained from a shame and blame mentality where individuals, their parents, teachers and other groups are singled out as causes of the problem. Such an approach does little more than shift attention from the main game of prevention and management of the condition, which requires a concerted, whole-of-government approach (in each country). The failure to support and encourage all young people to participate in regular PA will increase the chance that our children will live shorter and less healthy lives than their parents. In short, we need novel environmental approaches to foster a systematic increase in PA. This paper provides examples of opportunities and challenges for PA strategies to prevent obesity with a particular emphasis on the school and home settings.
This study investigated the potential of a classification procedure to determine type, duration, and frequency of children's physical activity (PA) during 7 days based on accelerometer data. Hip and wrist accelerometer data (1-second epoch) were collected over a week in 41 children (age: 10.7 ± 0.9 years). The classification procedure was used to assign each second into one of the following four categories: stationary activities, walking, running, and jumping. A diary was used to assess the simultaneous activity setting. Children spent 75.5% of the time (600.9 ± 80.1 minutes/day) on stationary activities, 15.6% (124.6 ± 33.6 minutes/day) on walking, 2% (16.1 ± 8.6 minutes/day) on running, and 1% (4.7 ± 5.2 minutes/day) on jumping. The median duration of stationary activities, walking, running, and jumping was 4, 2, 1, and 1 seconds, respectively. The largest proportion of running and jumping occurred during outdoor sport training (10.7%), physical education classes (6.7%), and vigorous outdoor activity (6.1%). The classification procedure used in this study shows the potential for analyzing children's PA in free-living conditions. The study results revealed that children's PA is characterized by very short activity bouts and that providing the possibility for children to participate in structured or unstructured outdoor activities might increase their PA. Therefore, the classification procedure enhanced the analysis of the transitory nature of children's PA and the understanding of their PA behavior during different activity settings.
The aim of this study was to compare the effect of endurance training (ET), resistance training (RT), and concurrent training (CT) on circulating antioxidant capacity and oxidative stress. For this purpose, 30 men aged 21.7 ± 2.4 years were assigned to the following three training groups: ET, which included continuous running with incremental intensity that was increased up to 80% of maximal heart rate (n = 10); RT, which included a beginning load of 50% of one repetition maximum (1RM) that was increased up to 80% of 1RM (n = 10); and CT, which included ET and RT programs every other day during the week (n = 10). Activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in erythrocytes and total antioxidant capacity (TAC) and malondialdehyde (MDA) level in plasma were measured. The results showed that SOD significantly increased by 21.85% (p = 0.020), 9.54% (p = 0.032), and 14.55% (p = 0.038) in the ET, RT, and CT groups, respectively. Furthermore, the activity of erythrocyte GPx significantly increased in the ET (p = 0.018) and CT (p = 0.042) groups. The TAC increased significantly in the ET (p = 0.040) and CT (p = 0.049) groups compared with the pretest values. The MDA level significantly decreased in the ET group by 32.7% (p = 0.028), by 32% in the RT group (p = 0.025), and by 29.1% (p = 0.047) in the CT group. However, there was no significant difference in the interaction of time and group between variables of SOD and GPx enzymes and TAC of plasma and MDA in the ET, RT, and CT groups (p < 0.05). It can be concluded that all three training types induced the same changes in redox state (increased SOD activity and reduction in MDA levels), but at different rates.
Resistance training is an effective way to achieve optimal gains in muscle mass and strength and has also been well documented in attenuating various forms of skeletal muscle wasting (e.g., sarcopenia). Moreover, it has been demonstrated that with appropriate training, older adults can reverse strength and muscle mass deficits to younger levels. To attain maximal benefits, careful manipulation of training variables, such as intensity, volume and frequency, is required. Although training intensity and training volume have been extensively studied, there is only scarce information available on the adaptive responses to frequency manipulations in older populations. Thus, we compared the effects of short-term (8 weeks) resistance training programs performed either 2 days/week (n = 15, 7 males, 8 females) or 3 days/week (n = 14, 4 males, 10 females) on muscle mass, upper- and lower-body strength and functional abilities in individuals aged > 60 years. Chest press strength increased in both the 2 times/week and 3 times/week groups over the 8-week training period by 20.84% and 20.18%, respectively. Lower-body (leg press) strength also showed improvements in both groups: 22.34% in the 2 times/week group and 28.12% in the 3 times/week group. There was a slight, but nevertheless significant gain of lean body mass from pre- to post-training (2.4% and 1.9% for the 2 days and 3 days groups, respectively). However, functional performance remained unchanged in the groups. We found that short-term resistance training 2 times/week or 3 times/week elicited comparable muscle strength and lean body mass adaptations in older adults.
Current research suggests that a decline in physical activity occurs some time during the adolescent years, but at what specific age is unknown. Determination of the age at which physical activity levels decline and possible contributors to this phenomenon, are needed to increase Australian healthcare knowledge. The participants involved in the study were female adolescents (n = 297) aged 13-15 years from a high school in Southeast Queensland, Australia. The purpose of this study was to: (a) determine mean steps per day, using pedometers, for grade 8 through 10 girls, (b) determine body mass index (BMI) by measuring height (cm) and weight (kg), and (c), using the Children and Youth Physical Self-Perception Profile (CY-PSPP) questionnaire, identify determinants of physical self-worth in Australian female adolescents and their relationship to activity level and BMI. The study revealed that a significant drop-off in pedometer-determined mean daily steps occurred at grade ten, or approximately 15 years of age. A significant inverse relationship between mean daily steps and BMI was found (r = ¯.251, p<.0001). The study also revealed negative correlations between BMI and all self-perceptions (p<.05), except strength, which showed a positive correlation (p<0.05). A positive correlation was found between level of physical activity and all self-perceptions, except Global Self-Worth, which showed no significant difference.
This study aimed to assess the impact of a multidisciplinary program of obesity treatment (MPOT) on adolescents who have maintained/gained weight or lost weight. Eighty-six adolescents aged 10-18 years were allocated in either the intervention group (IG; n=44) or the control group (CG; n=42). Each group was divided into two more groups: weight maintenance/gain and weight loss, as assessed after the intervention. The MPOT lasted 16 weeks and was conducted by a multidisciplinary team based on cognitive-behavioral therapy. We analyzed body composition and cardiometabolic parameters prior to and after the intervention. Adolescents from the IG who lost weight showed improvements in maximal oxygen uptake (23.54±5.30mL/kg/minute vs. 25.39±5.63mL/kg/minute), body fat percentage (49.29±6.98% vs. 46.75±8.56%), triglyceride levels (116.58±46.50mg/dL vs. 101.19±43.08mg/dL), diastolic blood pressure (75.81±8.08mmHg vs. 71.19±6.34mmHg), and the number of risk factors for metabolic syndrome (2.00±1.06 vs. 1.58±1.10). Adolescents from the IG who gained/maintained weight reported reduced body fat percentage (48.81±5.04% vs. 46.60±5.53%), systolic blood pressure (123.39±14.58mmHg vs. 115.83±7.02mmHg), diastolic blood pressure (74.83±9.91mmHg vs. 68.78±5.95mmHg), and number of risk factors for metabolic syndrome (from 1.67±1.09 to 1.11±0.68), and their lean mass (39.00±7.20kg vs. 41.85±7.53kg) and maximal oxygen uptake (23.74±4.40mL/kg/minute vs. 25.29±5.17mL/kg/minute) increased in a manner similar to those of adolescents who lost weight. Furthermore, we noted significant decreases in body mass index, body fat (kg), glycemia, and waist circumference in CG adolescents who lost weight, whereas those in the CG who maintained/gained weight had an increase in body mass index, hip circumference, body fat (kg), and lean mass. A 16-week MPOT promoted positive changes in body composition and cardiometabolic risk factors independently of weight changes.
Health-enhancing physical activity (HEPA) is a primary resource for improving physiological and psychosocial health. Stage models in the HEPA promotion area should fulfill three functions: description, intervention, and diagnosis. However, these functions have received insufficient attention, and research using an intercultural study paradigm has been rather scarce on this topic. The purpose of this study was to examine the three functions of a stage model by addressing the steps and correlates of HEPA behavior change process among adult samples from Germany and China. The 2071 adults (42% German and 58% Chinese), who were aged 27–55 years, completed self-administered questionnaires that assessed the quantity, intensity, and type of physical activity (PA) and assessed the stage of change. The following were also measured: five health correlates (i.e., fitness, physical complaints, body mass index, health satisfaction, and subjective well-being) and 10 psychosocial correlates (i.e., outcome expectations, affective attitude, barriers, self-efficacy, body concept, plans, intrinsic motivation, assessment of activity situation, activity emotions, and social support). The PA stages were significantly and positively correlated with the weekly energy consumption. In the health correlates and stages of change, all five health correlates significantly differed between the stages. In the psychosocial correlates and the stages of change, nine of 10 psychosocial correlates (with the exception of assessment of activity situation) significantly discriminated between the stages of change. In particular, nationality, gender, and education level are moderating factors for the characteristics of most health correlates across all stages of change. In addition, nationality, gender, and age moderated the relationship between the stage of change and some psychosocial correlates. The findings generally support the utility of a stage model for understanding German and Chinese adult HEPA behavior.
The number of people who are overweight or obese is increasing worldwide and the quality of life of these people can be affected by their condition. Physical training has been studied in obese patients and is correlated with low-grade inflammation and alterations in the immune system. This study investigated the effect of concurrent training on anthropometric, inflammatory, and immunological parameters in overweight and obese adults. Fourteen sedentary volunteers (men and women) with a body mass index between 25 kg/m2 and 39.9 kg/m2 from Porto Alegre, Brazil attended a 12-week course of concurrent training. We analyzed: prior to and after training, anthropometric parameters, cytokine serum levels (interleukin 6, tumor necrosis factor α, interferon γ, interleukin 17A and interleukin 10; measured by enzyme-linked immunosorbent assay), high-sensitive C reactive protein (measured by turbidimetry), and the frequency of T lymphocytes and monocytes (CD3+CD4+, CD3+CD8+, and HLA-DR+) in peripheral blood (measured by flow cytometry). The sample consisted of ten women and four men with a mean ± SD age of 47.58 ± 3.01 years. After 12 weeks of training we observed a reduction in body weight, body mass index, waist, abdomen, and hip circumferences, the percentage mass of fat, and an increase in the time taken to reach exhaustion (p < 0.05). The participants had increased frequencies of CD3+CD4+ and CD3+CD8+ T lymphocytes and a reduction in the frequencies of HLA-DR+ monocytes (p < 0.05). Interestingly, the levels of tumor necrosis factor α and high-sensitive C reactive protein increased (p < 0.05). Our data suggest that concurrent training can improve body composition as well as increasing T cell proliferation in overweight and obese patients. However, the progression of the exercises can be physiologically stressful to these patients, as demonstrated by the inflammatory markers.
Previous studies suggest that the maximum oxygen uptake (VO2max) and the Wingate anaerobic test performances are decreased in hot environments, but it is unknown whether humidity changes in a hot environment further affect the results of the VO2max and Wingate anaerobic test. Nine male athletes performed VO2max and Wingate anaerobic tests under three environmental conditions: (1) 21 °C/20% relative humidity (R.H.) (control); (2) 33 °C/20% R.H. (hot–dry); and (3) 33 °C/80% R.H. (hot–wet). The participants' weight, oral temperature, and skin temperature were recorded pre-exercise and postexercise. The heart rate was monitored continuously throughout the exercise. Compared to the control condition, the hot–dry and the hot–wet conditions had lower VO2max values (control at 3779.0 ± 234.3 mL/min vs. hot–dry at 3528.2 ± 467.4 mL/min and hot–wet at 3595.9 ± 274.6 mL/min; p < 0.05). However, there was no difference in the VO2max between the hot–dry and the hot–wet conditions. A decrease in the postexercise oral-to-skin temperature gradient was strongly correlated with decreased VO2max (mL kg−1 min−1) in all conditions (r = 0.835, p < 0.001). There was no significant difference between the conditions in the peak power and anaerobic capacity during the Wingate anaerobic test. The VO2max was impaired in the hot–dry and in the hot–wet conditions, compared to the control condition; however, the different humidity levels (i.e. hot–dry vs. hot–wet) had no effect on the VO2max. The postexercise oral-to-skin temperature gradient was in line with the variance in VO2max in all three different environmental conditions. The Wingate anaerobic test performance was not affected by the hot–dry or the hot–wet conditions, compared to the control environment. These results suggest that different relative humidity conditions do not affect the VO2max or the Wingate anaerobic test performance in hot environments.
The aging process occurs at different rates among different tissues. The complication of the definition of aging is due to the occurrence of various diseases that modify body functions and tissue structure. Advances in medicine and public health have considerably increased life expectancy over the past 200 years. An enormous effort has recently been expended to understand how the aging process is regulated at the molecular and cellular levels with hopes to find a way to extend maximal life span. There are several determinants of life span, but one common thread that has emerged in a variety of species from yeast to rodents is regulation of life span by mitochondria. Mitochondria decay that occurs with age cannot be counteracted unless physical activity is enhanced. As the frontiers of understanding the senescence and life span increases, the countermeasures for reducing aging senescence has brought to light the effectiveness of enhanced physical activities in aging individuals. Regular aerobic exercise may increase healthy life expectance and prolong life through beneficial effects at the mitochondrial level.
This study examined two hypotheses: (1) a non-Wingate-based high-intensity interval training protocol of 20×30-second cycle exercise at 120% of peak aerobic power interspersed with 60-second recovery per session, 3 sessions per week for 6 weeks, can enhance cardiorespiratory fitness and aerobic-based exercise capacity; and (2) proportional-assist ventilation (PAV) can augment interval training intensity, and, in turn, enhance the adaptations to the training in sedentary and mild obese individuals. Sixteen subjects were paired up and assigned into an interval training (IT) group or IT plus PAV (IT + PAV) group. During the 6-week interval training program, the increase in training intensity was not different between the IT and IT + PAV groups (p > 0.05). Nevertheless, significant improvements were found in the peak work rate and peak O2 during the post-training incremental cycling test in both groups. Moreover, the limit of tolerance during the post-training constant-load cycling test (70% of pre-training peak aerobic power) was enhanced, while blood lactate accumulation, heart rate, ratings of breathing discomfort, and perceived exertion at the iso-time point of the pre-training test at exhaustion were reduced (p < 0.05). The interaction effect on the change in each variable between the two groups was not significant (p > 0.05). In conclusion, the 6-week non-Wingate-based high-intensity interval training protocol was preliminarily found to enhance cardiorespiratory fitness and aerobic-based exercise capacity in sedentary and mild obese subjects. The provision of PAV during the interval training did not augment training intensity and subsequent aerobic adaptations.
This study examined, in a naturalistic setting, affective changes in 15 women. Measurements were obtained presession, postsession, and at 10-minute intervals during three aerobics sessions that were conducted at high (HI), low (LI) and self-selected (SS) intensities. The intensity was manipulated via changes in music tempo and movement size. Scores on the Feeling Scale (FS) and the Felt Arousal Scale (FAS) were subjected to two-way repeated measures analysis of variance (ANOVA). Circumplex models were constructed to display the path followed by the affective changes throughout the course of each exercise session. A main effect for time and condition emerged in that the FS scores were more positive in the SS intensity participants than in the LI participants, and the post-test FS scores were more favorable than they were at pretest or at 10 minutes, 20 minutes, 30 minutes, or 40 minutes. The FAS scores were higher in the SS intensity participants and HI participants than in the LI participants. A difference only emerged between the SS intensity and HI participants at the 20-minute interval. Variability in the circumplex profiles was evident across each intensity level and for each participant. The study supports and extends previous work in confirming that: (1) exercise can positively influence affective changes in ecologically valid settings; (2) a self-selected intensity is the most beneficial for producing affective changes; (3) idiosyncratic patterns of affective change occur when exercising at different intensities. The implications of these findings for exercise professionals are discussed.
The purpose of this study was to investigate the effects of regular training on lymphocyte proliferation, plasma cytokine levels, and parameters of neutrophil and lymphocyte death in young women (YW) and middle-aged women (MAW). Thirteen untrained YW, 12 untrained MAW, 12 trained YW, and 17 trained MAW participated in this investigation. The characteristics measured were lymphocyte proliferation, plasma cytokine levels, and parameters of neutrophil and lymphocyte death (viability, DNA fragmentation, phosphatidylserine externalization, and mitochondrial depolarization). The lymphocyte proliferation of untrained MAW was 30% lower than that of untrained YW. The YW had a significant decrease in the viability of lymphocytes and neutrophil compared with that of MAW (p < 0.05). The training prevented the loss of neutrophil viability observed in YW (p < 0.05). By contrast, regular exercise caused increases in lymphocyte apoptosis in both YW and MAW (p < 0.05) and neutrophil apoptosis in MAW only (p < 0.05). The plasma concentration of interleukin-1ra (IL-1ra) was increased (fourfold) by regular activity in YW, and the IL-2 plasma levels were increased (twofold) in the YW compared with those of MAW. Lymphocyte function and cytokine release were impaired in MAW, and regular activity partially prevented these alterations.
The purpose of this study was to explore the effects of AMPKα2 knockout on expression of GLUT4 after exercise with different intensities. This was investigated in the quadriceps femoris muscle from control, lower intensity (12 m/minute) and higher intensity (20 m/minute) running groups of wild-type (WT) and AMPKα2 knockout (KO) mice. The skeletal muscle glycogen content was also measured to investigate the role of AMPK in regulation of glycogen metabolism. GLUT4 mRNA was increased immediately at the end of 60 minutes of running, but there were no differences between WT and KO mice, and between lower intensity and higher intensity groups. Pre-exercise muscle glycogen levels were not different between WT and KO; however, the lack of the α2-isoform was associated with a generally lower level of muscle glycogen after 60 minutes of running either with lower intensity or higher intensity. The finding that KO of the AMPKα2 isoform had no effect on expressions of GLUT4 mRNA and protein expression in mouse skeletal muscle and that muscle glycogen degradation was greater in AMPKα2 KO mice than that in WT mice after different intensity exercises, provides further evidence that AMPK is dispensable in exercise-induced expression of GLUT4, and suggests alternative pathways other than GLUT4 being involved in the regulation of muscle glycogen degradation by AMPK. Also, the present investigation demonstrated that higher intensity (20 m/minute) treadmill running, lasting 1 h, increased GLUT4 mRNA in mice skeletal muscle to a level similar to that attained after 1 h of lower intensity (12 m/minute) treadmill running.
Functional disruption following eccentric exercise-induced muscle damage is characterized by an immediate and prolonged loss in force-generating capacity, a disproportionate loss of strength at short muscle lengths, and a rightward shift in muscle length-tension relationship, in favor of a longer muscle length for optimal force generation. The purpose of this study was to examine progressive changes in muscle joint angle-torque characteristics following strenuous eccentric exercise in the quadriceps group, in female athletes. Seventeen physically active female athletes completed eccentric exercise designed to induce muscle damage. Isokinetic dynamometry was used to determine characteristics of muscle strength loss for the following dependant variables: change in maximal force, force at optimal and short muscle lengths, and shift in length-tension relationship at 1 hour, 24 hours, 48 hours, 72 hours, and 96 hours following damaging exercise. Perceived soreness and creatine kinase activity were also measured at these times. Significant increases in perceived soreness and creatine kinase activity, and a significant reduction in force-generating capacity were observed. A greater strength loss at short muscle lengths was observed following damaging exercise [17.2% vs. 25.7% relative force reduction for optimal and short (71° and 21° from full extension) muscle lengths, respectively]. A significant rightward shift in optimal joint angle for force generation was also observed, indicating that maximal force was generated at a longer muscle length subsequent to damaging exercise. This paper demonstrates a progressive rightward shift in the muscle length tension relationship.
Background: Physical inactivity and high levels of screen time may negatively affect health-related quality of life (HRQoL) levels in children and adults.
Objective: To analyze the associations between HRQoL and television (TV) viewing time adjusting for physical activity and weight status among school-age children.
Methods: The study was conducted in Monteria, Colombia, with 546 students aged 11–18 years, from 14 randomly selected schools. HRQoL data was collected using the Pediatric Quality of Life Inventory (PedsQL). Students completed a self-reported questionnaire including items describing TV viewing time and physical activity. Associations between HRQoL and TV viewing time were explored using logistic regression models.
Results: Adjusted odds ratios (OR) showed that high TV viewing time (>2 hours/day) is significantly associated with low HRQoL [OR: 1.5; 95% confidence interval (CI): 1.0–2.2; p = 0.048], low psychosocial health (OR: 1.8; 95% CI: 1.2–2.5; p = 0.005), low emotional functioning (OR: 1.9; 95% CI: 1.4–2.6; p = 0.001), low social functioning (OR: 1.4; 95% CI: 1.0–1.9; p = 0.046), and low school functioning (OR: 1.5; 95% CI: 1.1–2.2; p = 0.025).
Conclusion: This study provides evidence of significant associations between high TV viewing time and poor HRQoL among school-age children from Monteria, Colombia, which were independent of physical activity and weight.
Given the growth in sport participation by masters athletes, the purposes of this paper are to: (1) describe record-level performances of masters athletes in running, swimming and cycling; (2) delineate the age- and gender-related performance decline that occurs in masters athletes in these sports; (3) explain how physiological, sociological and psychological factors affect masters level performance; and (4) provide some tips for continued healthy participation of the masters athlete. World and USA records (criterion and age-group) were plotted by age and gender for masters competitors in running, swimming and cycling. Percent difference was calculated for age-related performance [(age group record – criterion record/criterion record) × 100] and for gender [(women’s record – men’s record/men’s record) × 100]. The smallest performance differences existed between world record performances and records for the youngest masters level competitors (e.g. 35–49 years old). The largest performance differences existed between world record performances and the oldest masters level competitors (e.g. ≥ 80 years old). The slope in declining performances increased notably after the age of 55 years, and women’s performances tended to decline faster than those of men, especially in running. In the ≥ 80 years old group, performance declined at a rate that approached or exceeded 100%. Gender differences in middle-distance swimming performance were small compared to gender differences in running and cycling. Although younger athletes still have the advantage with regard to overall performance, masters athletes can continue to compete effectively in a variety of events until late in life.