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.
There is limited information on the acute immune response to resistance-training programs in combination with short-term administration of the anabolic androgenic steroid, testosterone enanthate (TE), in healthy young males. Eighteen healthy young men were match-paired and randomly assigned in a double-blind manner to either a TE or a placebo (PG) group. All subjects performed a structured resistance-training program while receiving injection of either TE at the dosage of 3.5 mg per kilogram body mass, or saline as placebo, once weekly for 6 weeks. A 10-second all-out cycle sprint test was conducted at the beginning (Week 0) and end (Week 6) of the treatment period. NK, B and T lymphocyte populations were counted and natural killer cytotoxic activity (NKCA) was measured prior to and 5 minutes post the cycle sprint at Weeks 0 and 6. The TE group significantly increased their total work in the 10-second cycle sprint test from Week 0 to Week 6 (p< 0.04), while there was no significant increase for total work in the PG group. There was a significant increase in NKCA from Week 0 to Week 6 (p < 0.05) in the PG group. A significantly higher NKCA in the PG group than in the TE group was found in the post exercise sample in Week 6 (p < 0.04). No significant differences were found between groups for the lymphocyte subsets. The 6-week strength training increased acute NKCA response to anaerobic type of exercise as shown in the PG group. Although dosing of TE enhanced anaerobic performance, the NKCA response in the TE group was lower than that in the PG group. The impact of this altered immune response on athletes' health requires further investigation.
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.
Physiologic hypertrophy of the athlete heart, compared to the heart of nonathletic controls, is characterized by an increase in the left ventricular (LV) chamber dimension, mass, and wall thickness. Comparisons of the diastolic function (DF) between athletes and controls have employed conventional echocardiographic transmitral flow (Doppler E-wave)-derived indexes such as the peak flow velocity and deceleration time (which are load-dependent) and obscure the mechanistic determinants (e.g., stiffness, relaxation, load) of E-wave. With a focus on stiffness and relaxation chamber properties, conventional kinematic model-derived and load-independent indexes of the DF were compared between athletes and controls in this study. Echocardiographic and magnetic resonance imaging (MRI) data from 22 master athletes (whose sport was canoeing) and 21 sedentary controls were analyzed (1290 Doppler E-waves; 702 from athletes and 588 from the controls; on average, there were 30 pieces of data per subject). The LV mass and chamber size were determined from the MRI data. Quantitative DF assessment utilized an established kinematic model of filling that used the digitized Doppler E-wave contour as the input and characterized the DF on the basis of the chamber stiffness (k), relaxation/viscoelasticity (c), load (xo). We observed significant chamber stiffness (k), load (xo), and E-wave duration differences between the two groups. Concordant with the findings of previous studies, we also noted significant group differences in LV mass and dimension. These results indicated that physiological LV remodeling of the athlete heart at rest generates numerically quantifiable alterations in specific chamber properties. Assessment of the DF by using these methods during exercise will further elucidate the dynamic interplay between relaxation and stiffness as DF determinants.
Determining the key factors in athletic performance is important for developing the technique and strength of athletes. Many martial arts forms have been studied, but a relatively new form of martial arts competition, San Shou, has not been analyzed. The purpose of this study was to determine key attributes necessary in the development of the San Shou athlete, particularly in female participants. Six elite and six novice competitors performed 30 continuous repetitions of cyclic extension and flexion of the trunk segment, knee joints, and elbows joints at two velocities, 60°/second and 180°/second, using an isokinetic dynamometer. Variables of interest were maximum torque production, normalized torque (Nm/kg), fatigue indexes (average of three maximal forces in the first three cycles/average of maximal forces in the last three cycles), and rate of torque development (Nm/s). Results indicate significant differences between groups only during trunk flexion for maximum torque, normalized torque, and rate of force development, whereas differences between movement velocities were apparent for multiple variables at each anatomic region. These analyses assist in providing further information regarding the possible key factors in developing the San Shou female athlete. Further work is required to identify additional parameters in developing the San Shou athlete.
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.
This cross-sectional study examined whether the prevalence of behavioral and biological risk factors of former elite athletes (both men and women), differed from nonelite athletes and nonathletes. A total of 491 individuals (225 former elite athletes, 168 former nonelite athletes, and 98 nonathletes) participated in this study. Major behavioral and biological risk factors identified in the 2002 World Health Report were assessed. Apart from alcohol consumption, former elite athletes had at least 70% lower likelihood than nonathletes for the other behavioral risk factors. Regarding biological factors, being overweight/obesity seems to be the one where minor differences exist, with a significant odds ratio only among female former elite athletes (0.09, p < 0.001) when compared to nonathletes. In general, the results showed healthy outcomes among former elite athletes. Albeit the results extend to both sexes, women appear to have slightly healthier outcomes. Being a former athlete, especially at an elite level, seems to be associated with decreased risk factors for major chronic diseases.
The purpose of this study was to examine the effect of glutamine supplementation on indices of recovery following eccentric exercise. In a randomized single-blind placebo-controlled design, 15 physically active males (mean age, 21 ± 1.5 years; mean height, 1.81 ± 0.07 m; mean body mass, 78.4 ± 9.2 kg) were assigned to a control or glutamine intervention group. Each participant performed 100 drop jumps from 0.6m followed by ingestion of 0.3 g · kg−1 body mass of maltodextrin mixed with 750 mL of distilled water and lemon flavoring (Control) or with an additional 0.3 g · kg−1 L-glutamine (Glutamine) at 0, 24, 48, and 72 hours post-exercise. Knee-extensor concentric peak torque at angular velocities of 0.52 and 3.14 rad · s−1, perceived muscle soreness, and plasma creatine kinase activity were measured at 0, 1, 24, 48, 72, and 96 hours post-exercise. L-glutamine supplementation resulted in a greater preservation of peak torque over the 96-hour measurement period at both 0.52 rad · s−1 (Control, 75 ± 16%; Glutamine, 85 ± 15% of pre-exercise values, p = 0.03) and 3.14 rad · s−1 (Control, 79 ± 16%; Glutamine, 90 ± 12%, p = 0.01). Muscle soreness was significantly lower over 96 hours with L-glutamine supplementation (Control, 4.6 ± 2.5 units; Glutamine, 3.6 ± 2.5 units, p = 0.03). L-glutamine supplementation did not affect the magnitude or temporal nature of the creatine kinase response. As a therapeutic intervention, glutamine supplementation was effective in attenuating strength loss and muscle soreness following eccentric exercise-induced muscle damage.
Previous research reports positive effects of yoga on health. The physical and psychological outcomes of participation in Bikram yoga are under-researched despite its increasing popularity, and this type of yoga may be significant with regards to stress management due to its unique method of practice. This study was designed to assess changes in levels of mindfulness, perceived stress, and physical fitness after participation in an 8-week Bikram yoga program. Fifty-one participants aged 20–54 years (mean, 31.57 years) were recruited by word of mouth from a large university located in the Northwestern United States. Participants attended a minimum of 20 Bikram sessions over 8 weeks. Changes in mindfulness (Five-Facet Mindfulness Questionnaire), perceived stress (Perceived Stress Scale), and physical fitness (resting heart rate, 1-mile walk, sit-and-reach, total-body rotation, and single-leg balance) were measured. Eight weeks of Bikram yoga improved mindfulness, perceived stress, cardiorespiratory endurance, flexibility and balance (p < 0.01). Mindfulness was negatively correlated with perceived stress (r=−0.43, p < 0.01) and resting heart rate (r=−0.30, p < 0.05). The results show that Bikram yoga positively affected psychological and physical health in the sample population. This information can be used to further the understanding of mind-body based programs, and how Bikram yoga may give people the tools to decrease perceived stress, potentially having an effect on chronic stress-related illnesses.
To provide the current evidence linking physical activity to breast cancer risk, the objectives of this review were twofold: (1) to review the epidemiological literature examining the relationship between physical activity and breast cancer risk; and (2) to summarize the mechanisms through which physical activity can influence risk. A review of the literature was conducted to identify studies that addressed these two objectives. Of the 76 studies reviewed, 40 (53%) reported a protective effect of physical activity on breast cancer risk. The protective effects of physical activity on breast cancer risk are likely to be through changes in sex hormone levels, immune function, adiposity, and insulin-related hormones. To achieve the greatest reduction in risk of breast cancer, regular participation in physical activity should begin in childhood and persist throughout the lifespan.
The main purpose of this study was to compare the effects of previous high-intensity aerobic exercise at 50 and 100 rev · min−1 on subsequent strength determined through maximal repetitions (RM) and countermovement jump (CMJ). Thirteen physically active males (age, 23.0 ± 3.7 years; weight, 77.1 ± 8.8 kg; height, 179.3 ± 4.0 cm; %body fat, 14.3 ± 2.9%) performed the following procedures on different days: (1) incremental test on cycle ergometer to determine the onset of blood lactate accumulation at 50 and 100 rev · min−1; (2) three sets of RMs with the load corresponding to 10 RM in leg press 45° (LC); (3) three sets of 10 maximal CMJ in contact plate (JC); (4) four trials of 30 minutes at the onset of blood lactate accumulation obtained at 50 and 100 rev · min−1, followed by three sets of RMs with 10 RM load (L50 and L100, respectively) or three sets of maximal CMJ (J50 and J100, respectively). Strength was compromised at 100 rev · min−1 (L100 = 22.6 ± 6.0 vs. LC = 30.4 ± 1.5 repetitions) in leg press, while CMJ height was reduced at 50 rev-min−1 (J50 = 29.2 ±3.0 vs. JC = 31.7 ± 2.9 cm). The reduction in number of repetitions at L100 (26%) was significantly higher than CMJ height at J50 (8%). In conclusion, the extent of strength loss after high-intensity aerobic exercise can be dependent on both pedal cadence and strength test conditions. When aerobic cycling exercise precedes strength training, it may be beneficial to use low pedal cadences to minimize strength loss.
Monitoring personal hydration status as well as examining the contents of sports beverages is crucial to improve physical performance in soccer players. This study examined the effects of 60 minutes of soccer-specific training on skill performance, hydration status, and core temperature (Tc) of soccer players after ingesting either a carbohydrate-containing (CHO) or a carbohydrate-free (CHO-F) drink. This study recruited seven healthy male soccer players (age: 23 ± 2.9 years, height: 1.7 ± 0.04 m, mass: 62.7 ± 6.7 kg), each of whom completed a CHO and a CHO-F trial in a randomized crossover design. The participants underwent skill tests [Loughborough Soccer Passing Test (LSPT)] prior to and after 60 minutes of training in a hot and humid environment (30 °C, 85% relative humidity). They consumed 2 mL of fluid per/kg body mass every 15 minutes during exercise. Blood glucose, blood lactate, and Tc were monitored throughout the exercise session. Improvement was observed in movement time (p = 0.034) and overall LSPT performance (p = 0.031) postexercise in those consuming CHO drinks compared with those consuming CHO-F drinks. No differences were observed in Tc or absolute and relative body mass loss between the trial groups (p > 0.05). Urine output was greater in the CHO trial group (CHO: 0.086 ± 0.051 L; CHO-F: 0.030 ± 0.028 L; p = 0.043). Compared with the consumption of a CHO-F drink, that of a CHO drink during a 60-minute soccer-specific exercise session in a hot and humid climate can improve postexercise skill performance. Additionally, Tc can be regulated efficiently by commencing training in a state of euhydration and by regular ingestion of fluids throughout the exercise period.
Thirty-two children (aged 7–11 years) were monitored for 4–5 consecutive days under two randomly assigned crossover treatment/non-treatment conditions (minimum of 2 days for each condition): (1) accelerometer (i.e., control or covert monitoring); and (2) accelerometer and pedometer (i.e., treatment or known monitoring). Participants were informed the accelerometer was measuring “time”—serving as the blinding condition. Paired analyses were performed between conditions for four time segments (warm-up and three activity units). A significant difference during the warm-up was observed. No other changes in activity levels were present. The findings suggest that during unrestricted play, children increase their activity when being monitored.
Peak oxygen consumption (VO2) is one of the strongest predictors of survival in patients with chronic congestive heart failure (CHF), but it is unavailable in most practices. Peak VO2 < 14 mL/kg/min identifies patients who might benefit from referral to a specialized CHF center. Accordingly, the current study was undertaken to derive a prediction formula based on routine stress data obtained from patients referred for cardiopulmonary exercise tolerance testing (CPETT). Subsequently, the prediction formula was validated in a separate cohort of similar patients referred for CPETT at another institution. The derivation cohort consisted of 208 patients with a diagnosis of CHF with reduced systolic function (left ventricular ejection fraction < 40%) who underwent elective CPETT. A multiple linear regression analysis was performed on available treadmill testing variables. A simple prediction formula was derived: Predicted peak VO2 = 16.7 – 1.3 (sex) – 3.8 × (New York Heart Association functional class) + 0.04 × (peak heart rate) + 0.92 × (estimated metabolic equivalents). The validation cohort consisted of 112 patients referred for CPETT at a different institution for the evaluation of advanced CHF. The predicted peak VO2 as obtained by the prediction formula was compared to the actual peak VO2 using a Pearson coefficient of correlation. The predicted peak VO2 was well correlated with the actual peak VO2 demonstrating a correlation coefficient of r = 0.77 with a 95% confidence interval of (0.68–0.83). A simple prediction formula using four variables that are routinely obtained in standard exercise treadmill testing can identify patients in whom formal CPETT is advisable and facilitate early referral to specialized heart failure centers.
Session ratings of perceived exertion (SRPE) have been considered to provide a quantitative evaluation of the entire exercise session in different types of resistance training. In this study we investigated the ability of SRPE to assess exercise strain in a circuit weight training (CWT) workout and the influence of time lag to report SRPE. Ten healthy male volunteers (22.3 ± 2.8 years, 72.5 ± 6.5 kg, and 175 ± 5 cm) completed a CWT session involving three circuits of five multiple joint exercises with single sets of 20 repetitions at 30% one repetition maximum (1-RM). Heart rate [63.7–75.0% maximum heart rate (%HRmax)], blood lactate (5.6–7.6 mM) as well as overall, chest, and active muscle RPE increased significantly (p < 0.05) throughout the CWT, but no significant differences were found between ratings of perceived exertion (RPE) types. Overall, chest and active muscle SRPE were accessed 10 minutes, 20 minutes, and 30 minutes after the workout, with no significant main effects or SRPE type × time interaction being found (p > 0.05). Finally, no significant differences (p > 0.05) were observed between averaged SRPE and RPE responses (overall: 3.7 ± 0.6 vs. 3.5 ± 0.9; chest: 3.8 ± 0.7 vs. 3.6 ± 0.8; active muscle; 3.7 ± 0.7 vs. 3.5 ± 0.7). These results suggest SRPE, irrespective of the moment at which it is taken, to be a useful tool for assessing global exercise strain in a CWT workout, providing coaches, physicians, and exercisers a practical way for monitoring this type of resistance training.
This crossover designed study examined the influence of textile hygroscopicity on skin temperature responses during 30 minutes of continuous cycling exercise at 60% O2peak in a thermoneutral environment (20°C and 50% relative humidity) in the convective airflow presence of forced convection (4.5 ± 0.2m · s−2) and under minimal convective airflow conditions. Ten well-trained male road cyclists completed two wear trials at random in the forced convection and minimal convective airflow condition wearing a long-sleeved cycling jersey that had a split design with a strongly hygroscopic (SH) fabric (wool) on one half and a weakly hygroscopic (WH) fabric (polyester) on the other half of the garment. The cyclists' mean age was 31±5 years, mean height was 1.81 ± 0.05 m, mean body mass was 83.55 ± 10.89 kg, and mean body surface area was 2.04 ± 0.14 m2. The previously reported actions of SH fibers increasing skin temperature through the evolution of sorption heat following moisture absorption, and subsequent elevation in fabric temperature, was assessed. An effect of WH fibers to impact skin temperature through increasing stratum corneum hydration, producing more skin-to-fabric contact and skin erythema, was also investigated. Similar physiological responses in the skin, including temperature, sweating, stratum corneum hydration (inferred from skin resistance) and erythema (indicated by luminous flux), were found for both the SH and WH fabrics under wind and no wind conditions. In conclusion, the textile hygroscopicity of the test garment was not found to significantly influence skin temperature during moderate-intensity cycling exercise for 30 minutes in a thermoneutral environment under minimal wind conditions and in the presence of forced convection.
The response of glucoregulatory hormones associated with the nadir in serum glucose (i.e., glucose threshold) was examined during graded exercise to exhaustion in 22 physically active male participants. A comparison was also made between the glucose, lactate, and ventilatory thresholds. The mean (±SD) age, height, and body mass of the participants was 24.5 (±4.0) years, 182.0 (±9.1) cm, and 84.8 (±17.4) kg, respectively. Blood samples were collected at rest and during the final minute of each power output of a graded exercise test. The nadir in blood glucose concentration occurred at the same time as the lowest concentration of plasma glucagon, and both were significantly elevated at maximal exercise. Insulin response showed a significant decrease from rest but was maintained prior to the glucose nadir followed by a significant decrease. Cortisol was significantly elevated at maximal exercise intensity only. There was no difference in the power output and oxygen consumption (VO2) at the glucose and lactate thresholds but both occurred at one power output prior to the ventilatory threshold. In conclusion, a nadir in serum glucose occurred in a predictable fashion in relation to other measures of anaerobic threshold. The nadir in blood glucose occurred prior to an increase in plasma glucagon concentration and a decrease in circulating insulin concentration during the re-establishment of euglycemia during graded exercise.
The purpose of this study was to determine whether central activation (CA) is reduced following a simulated 20-km cycling time trial (20TT) under normoxic and hypoxic conditions. It was hypothesized that CA, maximal voluntary contraction (MVC), and peripheral variables would become reduced during the 20TT exercise under both normoxic and hypoxic conditions, but to a greater extent under the hypoxic condition. Eight experienced male cyclists performed two simulated 20TTs in random order in a hypoxic chamber at either 15% or 21% fraction of inspired oxygen (FIO2). Using the interpolated twitch technique during MVC of the quadriceps, measurements were collected before the exercise, and at 1, 2, 3, and 4 minutes postexercise. The CA values at 1, 2, 3, and 4 minutes postexercise were all significantly reduced from the pre-exercise value. Significant decreases were also detected in all four postexercise MVC measurements and in the third and fourth peak twitch force (PTF) measurements. All four postexercise MVC measurements were significantly decreased. These findings suggest that CA, MVC, and PTF values were significantly reduced and remain reduced at 4 minutes following a self-paced, simulated endurance cycling performance. However, the hypoxic condition had no effect on CA, MVC, or peripheral variables when compared with the normoxic condition.
While the reliability of running economy (RE) has been widely established, limited investigation has been carried out into the reliability of various performance variables during a RE test. Subsequently, the purpose of the current study was to examine the reliability of time-to-exhaustion (TTE) and rating of perceived exertion (RPE) during a RE test among trained runners and moderately endurance-trained men. Absolute VO2 (mL/minute), VO2 relative to body mass (mL/kg/minute), oxygen cost of running (CR) defined as VO2 relative to body mass raised to the power of 0.75 per meter (ml kg (-0.75)/m), heart rate (HR), ventilation (V-E), carbon dioxide production (VCO2), respiratory exchange ratio and RPE were measured while treadmill running on two occasions at three discontinuous incremental speeds corresponding to 70%, 90%, and 110% of the second ventilatory threshold (VT2). The duration of the last increment was measured as TTE. The reliability was determined using the intraclass correlation coefficient (ICC) and 95% ratio limits of agreement. The intraindividual variability was examined using the coefficient of variation (CV). There were no significant differences between the two RE trials for absolute VO2, relative VO2, CR, V-E, VCO2, respiratory exchange ratio and RPE (p >= 0.05) except for the differences in RPE during the first increment and the TTE (p < 0.05). The reliability was high for absolute VO2, relative VO2, CR, HR and TTE and was moderate for V-E and RPE. Small intraindividual variability was found for absolute VO2, relative VO2, CR, HR and RPE. The findings will enable sport scientists to incorporate a variety of performance variables when examining RE. Copyright (c) 2012, The Society of Chinese Scholars on Exercise Physiology and Fitness. Published by Elsevier (Singapore) Pte Ltd. All rights reserved.
The purpose of this study was to investigate the effects of 8 weeks of supervised exercise training at the exercise intensity at which the maximal fat oxidation occurred (Fatmax intensity) on body composition and cardiorespiratory function in overweight young women. Fifty sedentary female university students [aged 20–23 years, body mass index (BMI) >25 kg/m2] were enrolled in the study. The maximal fat oxidation rate was measured using a graded treadmill running test; the average result of the participants was 0.43 ± 0.01 g/minute, which occurred at the exercise intensity of 54.0 ± 4.0% maximal oxygen consumption (VO2max), and the corresponding heart rate was 134 ± 3 beats per minute. The individualized heart rate at the Fatmax intensity was applied in the exercise training program. The trained individuals decreased their body mass, BMI, fat mass, waist–hip ratio, fasting plasma triglycerides, and total cholesterol concentrations and increased their VO2max and heart rate index in a step test. There were no changes in these variables in the control group. In conclusion, exercise training at the Fatmax intensity is an evidence-informed and safe exercise prescription for overweight young women.
The ventilatory threshold (VT), or respiratory compensation point, is an important respiratory-metabolic marker of aerobic fitness. Exercise at VT intensity provides an optimal stimulus for body mass loss and improvement in aerobic fitness. The use of ratings of perceived exertion (RPE) to self-regulate exercise intensity is more feasible than prescribing exercise using oxygen consumption (V˙O2) and heart rate (HR). Identifying RPE at the VT (RPEVT) is an optimal intensity target for perceptually regulated exercise. The aim of this study was to compare the RPEVT among normal body mass, overweight, and obese sedentary women, according to body mass index (BMI). Each participant performed a maximal graded treadmill test, where RPE, pulmonary ventilation, V˙O2, carbon dioxide output, and HR were monitored, and VT was determined. The RPEVT was identified as the RPE estimated during the minute the VT occurred. V˙O2, percentage of maximal V˙O2(%V˙O2max), and percentage of maximal HR (%HRmax) at the VT and RPEVT were compared among groups using analysis of variance. Obese women exhibited lower V˙O2,%V˙O2max, and %HRmax at the VT than other groups, with no differences between normal and overweight women. However, RPEVT was similar among groups. In summary, RPEVT was approximately 12 in sedentary women, regardless of BMI classification.
Surfing has become a popular sport activity in Australia and many other countries since 1960's. The first generation of surfers is now older than 60 years of age while many of them still surf regularly. Limited information is available in respect of the long-term physiological adaptations of participating in surfing. The aim of this study was to provide evidence on the effects of long-term surfing on neuromuscular function as compared to age-matched non-surfers. Eleven male surfers who had participated in surfing for at least 40 years volunteered for the study. A group of the age-matched and physically active men (n = 11) were recruited as the control. The physiological variables measured included maximal isometric voluntary contraction force (MVC), rate of force development, steadiness in muscle force production (knee extensors and flexors, and ankle dorsi- and plantar flexors) at 5, 15 and 25%MVC levels, joint position sense, and body sway in standing position under four different conditions: eye open or close and on hard or soft surface. The results indicated that older surfers had significantly lower muscle force fluctuations than the control subjects in the steadiness tests. The surfers also showed less postural sway in standing position with eye closed and on soft surface. The findings from this preliminary investigation suggest that long-term recreational surfing may cause specific adaptations that benefit participants by maintaining or improving their neuromuscular function which would ultimately lead to improved quality of life.
Excessive adiposity increases oxidative stress, and thus may play a critical role in the pathogenesis and development of obesity-associated comorbidities, in particular atherosclerosis, diabetes mellitus, and arterial hypertension. Improved body composition, through exercise training and diet, may therefore significantly contribute to a reduction in oxidative stress. Further, some foods high in antioxidants (e.g., ginger) provide additional defense against oxidation. This study was conducted to assess the effects of ginger (Zingiber officinale Roscoe) supplementation and progressive resistance training (PRT) on some nonenzymatic blood [total antioxidant capacity (TAC) and malondialdehyde (MDA)] oxidative stress markers in obese men. Thirty-two obese males (body mass index ≥30, aged 18–30 years) were randomized to one of the following four groups: a placebo (PL; n = 8); resistance training plus placebo (RTPL; n = 8); resistance training plus ginger supplementation (RTGI; n = 8); and ginger supplementation only (GI; n = 8). Participants in the RTGI and GI groups consumed 1 g ginger/day for 10 weeks. At the same time, PRT was undertaken by the RTPL and RTGI groups three times/week. Resting blood samples were collected at baseline and at 10 weeks, and analyzed for plasma nonenzymatic TAC and MDA concentration. After the 10-week intervention, we observed significant training × ginger supplementation × resistance training interaction for TAC (p = 0.043) and significant interactions for training × resistance training and training × ginger supplementation for MDA levels (p < 0.05). The results of this study show that 10 weeks of either ginger supplementation or PRT protects against oxidative stress and therefore both of these interventions can be beneficial for obese individuals; however, when combined, the effects cancel each other out.
The purpose of this study was to determine the effects of 12 weeks of high-intensity interval training (HIIT) on visfatin and insulin resistance (IR) in overweight adult men during a weight-loss program. Eighteen overweight men (age = 31.8 ± 9.2 years; body mass index = 28.6 ± 1.4 kg/m2) were randomly recruited into one of the two groups, namely, HIIT (3 days/week, 20 minutes/day; 85–95% peak oxygen uptake) and diet-induced weight-loss combined (DHIIT; n = 10) and diet-induced weight loss only (DIO; n = 8). The DHIIT and DIO groups undertook a 12-week weight-loss intervention using a moderate isocaloric energy-deficit diet. Both DHIIT and DIO groups demonstrated a significant reduction in body weight (p < 0.01). Total fat mass (p < 0.05) and lean body mass (p < 0.05) were decreased in the DIO group with no significant changes in abdominal fat mass, plasma insulin concentration, homeostasis model assessment-estimated IR (HOMA-IR), blood glucose level, and plasma visfatin. In the DHIIT group, total fat mass (p < 0.01), abdominal fat mass (p < 0.05), plasma insulin concentration (p < 0.05), plasma visfatin (p < 0.01), and HOMA-IR (p < 0.05) were reduced and lean body mass remained unchanged. In conclusion, adding a low-volume 20-minute HIIT (three times/week) to an energy-deficit diet not only can improve the efficiency of weight-loss program in the reduction of body fat, plasma visfatin levels, and HOMA-IR, but also has a reservation effect on lean body mass.
For many years, motor performance ability (MPA) has been viewed as a multidimensional construct consisting of such specific components as endurance, strength, coordination, and flexibility. This report examines whether these assumed structures of MPA can be found empirically in children and adolescents. The Motoric-Module, conducted between 2003 and 2006 in Germany for the differentiated measurement of MPA from ages 6 to 17 (N = 2,840), made use of an eight-item performance test battery. This test battery was assumed to assess the five motor dimensions of endurance, strength, coordination under time pressure, coordination under precision demands and flexibility. A two-level model of MPA with these five motor dimensions as first order factors could be confirmed using confirmatory factor analysis. The path coefficient (p < 0.001) describing the direct effect from MPA to strength was 0.97, followed by the effect from MPA to coordination under precision demands (a = 0.73). The coefficient relating from MPA to coordination under time pressure was less (a = 0.64) and the lowest loadings shown for MPA are demonstrated for endurance (a = 0.36) and flexibility (a = 0.23). The first order factors showed significant direct effects on each of the observed variables. Therefore, a differentiated diagnosis of MPA in children and adolescents is possible. This is important for health care.
Physical inactivity is a persistent and worsening population health concern in Asia. Led by the Active Healthy Kids Global Alliance, Global Matrix (GM) initiative provides an opportunity to explore how regional and cultural differences across 18 Asian countries relate to physical activity (PA) participation among children and adolescents.
To synthesize evidence from the GM2.0 to GM4.0 (2016–2022) in Asian countries.
Report Card grades on behavioral/individual and sources of influence indicators were reported from 18 Asian countries. Letter grades were converted into numerical values for quantitative analyses. Based on this, cross-sectional and longitudinal analyses were conducted to investigate patterns and trends. Qualitative evidence synthesis was performed based on Report Card grades and published papers to identify gaps and suggest future recommendations.
In total, 18 countries provided grades for at least one round of GM, 12 countries provided grades for at least two rounds, and seven countries provided grades for all three GMs. Of possible grades, 72.8%, 69.2%, and 76.9% of the grades were assigned from GM 2.0 to GM 4.0, respectively. In terms of the Report Card grades, there was a slight decrease in behavioral/individual indicators from “D+” in GM 2.0 to “D-” in GM 3.0 but this reverted to “D” in GM 4.0. For the sources of influence, a “C” grade was given in all three rounds of GM. Longitudinal observation of seven Asian countries that provided grades in all three rounds of GM revealed that grades are generally stable for all indicators with some country-specific fluctuations. In future GM initiatives and research, considerations should be made to provide more accurate and rich data and to better understand contextual challenges in evaluating certain indicators such as Active Transportation, Active Play, and Physical Fitness in particular. Further, macro level factors such as socioeconomic/cultural disparities and gender-specific barriers, ideology, or climate change should also be proactively considered in future research as these factors are becoming increasingly relevant to indicators of GM and United Nation's Sustainable Development Goals.
Participation from Asian countries in GM has increased over the years, which demonstrates the region's enthusiasm, capacity, and support for global PA promotion efforts. The efforts to promote a physically active lifestyle among children and adolescents should be a collective interest and priority of the Asia region based on the gaps identified in this paper.