The manipulation of exercise intensity in team sports constraints players and teams' technical, physical, and tactical behavior. According to that, the manipulation of the duration and the number of ...repetitions (i.e., using a continuous or a fractional method) of an exercise should constraint the overall exercise intensity and consequently its physical, technical and tactical demands. Thus, the aim of this study was to identify the effects of the use of a continuous or fractional method in external and internal load of players in football. The results show that the manipulation of the duration and the number of repetitions, using a continuous or a fractional method constraints external load of players. It means that coaches can constraint the time or the number of repetitions of the exercise according to the external load demands required for the training session.
Background and Objective: Cardiovascular and sports experts recommend the use of oxygen consumption cost indicators, heart rate and fatigue index to control work pressure in sports and ...rehabilitation. Meanwhile, it is very common to control the intensity of exercise by heart rate index. However, the maximum heart rate (HRmax) must first be measured or estimated as the basis for the calculations. The purpose of the present study is to evaluate the validity of HRmax estimation equations in healthy children. Materials and Methods: The HRmax was measured and estimated in 205 healthy boys between 8 and 12 years old by two methods, Bruce's incremental exercise test and special equations for children. In order to compare the estimated and measured HRmax, Pearson's correlation, t-correlated and root mean square error (RMSE) were used. Results: A weak correlation between estimated and measured HRmax was observed (R=0.09-0.18). A significant difference was observed between the estimated and measured HRmax (beats per minute = 1.4-4.8) (P<0.05). So, the Nikolaidis equation led to a significant overestimation and the Shargal and Gelbert equations led to a significant underestimation of the HRmax. Also, the root mean square error values for HRmax estimation equations were high (RMSE = 6.9 - 7.4 beats per minute). Conclusion: Considering the ineffectiveness of foreign equations for estimating the HRmax in Iranian children, it is recommended to design native equations for estimating the HRmax for Iranian children.
Exercise intensity is traditionally prescribed using %HRmax, %HRR, %VO2max, or %VO2R. Recently, the Talk Test (TT) has been proposed as an alternative method to guide exercise intensity. However, it ...is unknown if prescribing exercise intensity solely using the TT can provoke training responses that are comparable to traditional guidelines. This study compared the responses to training using either the TT or %HRR. Forty-four subjects (17 males and 27 females: age=20.4±3.02 years; body height=170.5±9.79 cm; body weight=71.9±13.63 kg) completed an incremental maximal cycle ergometer test, were stratified by VO2max and gender, and randomly assigned to training groups guided by either %HRR (n=20) or the TT (n=24). Both groups completed 40-minute training sessions three days per week for 10 weeks. In the HRR group, exercise intensity was targeted (per ACSM guidelines) at 40-59% HRR for weeks 1-4, 50-59% HRR for weeks 5-8, and 60-79% HRR for weeks 9-10. In the TT group, exercise intensity was targeted at the highest power output (PO) that still allowed for comfortable speech. Changes in VO2max, peak power output (PPO), VO2 at ventilatory threshold (VT), and PO at VT were compared between the groups using two-way ANOVA with repeated measures. There were significant (p0.05) interaction effect. Guiding exercise prescription using the TT is a simple and effective method for prescribing exercise intensity and elicits improvements in exercise performance that are comparable to the traditional %HRR guidelines.
Food reformulation has been suggested as an equitable approach to meeting recommendations to limit free sugars intakes. During reformulation, various ingredients are needed to replace the functional ...properties of sugars, however, the effect this has on levels of calories and “nutrients to limit” has not been examined on a large-scale. This study aimed to identify changes in nutritional composition of foods reformulated to be lower in sugars. Methods: This study was a repeated cross-sectional analysis of prepackaged foods and beverages using the 2013 and 2017 collections of the University of Toronto’s Food Label Database. Products in 2013 and 2017 were matched by barcode (n=6695 matches, after exclusions). Sign tests were used to evaluate difference in sugars contents. Wilcoxon signed rank test was used to evaluate differences in nutritional composition (i.e. calories, fat, saturated fats, sodium, carbohydrates, protein, and fibre) of products with lower sugars contents in 2017. Results: Twenty-two percent of products (n=1492) had changes in sugars contents between 2013 and 2017. In 2017, 10% (n=669) of products were higher in sugars by 39% (3.5 ± 5.0g per 100g/mL, p<0.0001) and 13% (n=882) were lower by 30% (-2.5 ± 2.8g per 100g/mL, p<0.0001). Products that had lower sugar levels in 2017, also had significant reductions in calories (-5.4 ± 22.2kcal per 100g/mL, p<0.0001), and sodium (-34.5 ± 186.9mg per 100g/mL, p<0.0001), and significant, but negligible, differences in saturated fats (0.0 ± 1.26g per 100g/mL, p=0.0435), total fats (-0.1 ± 1.7g per 100g/mL, p=0.0247), and carbohydrates (-0.8 ± 3.4g per 100g/mL, p<0.0001). There were no significant differences for other nutrients. Conclusion: Efforts to lower sugars contents through reformulation between 2013 and 2017 were limited. Although products reformulated to be lower in sugars were also significantly lower in calories, fats, carbohydrates, and sodium, the very small magnitude of these changes may not be sufficient to affect dietary intakes. (CIHR PICDP (JTB, TGF-53893); CIHR Training Program in Public Health Policy (JTB); OGS (JTB); CIHR Strategic Operating Grant (201103SOK-118150); Canadian Stroke Network (201103SOK-01194-000) (MRL); CIHR Sugars and Health (SA2-152805) (MRL); Earle W. McHenry Research Chair unrestricted grant (MRL); One Sweet Film Inc. (MRL).)
Exercise is an integral part of most domesticated horses’ lives. Understanding the frequency, duration, and intensity of exercise is important for determining the correct diet and management for the ...horse. The 2007 NRC categorizes exercise workloads into light, moderate, heavy, and very heavy to help determine the energy and nutrient requirements. The objective of the current study was to characterize the exercise management of horses in Pennsylvania. An online survey was distributed through Penn State Equine Extension's online outlets and through other Pennsylvania equine groups from February 27th to August 31st, 2020. NRC exercise workload guidelines were presented to respondents for them to self- report their horses’ exercise workload. Kurskal-Wallis and Mann-Whitney tests were used to analyze the data, and the significance level was set at P < 0.05. Nonparametric statistics were used when data were not normally distributed (Mdn = median). Of the 470 total responses collected, 58.5% of the horses were geldings, 39.8% were mares, and 1.7% were stallions. The average age was 15.7 years (SD = 7.5), and the most common breeds were the Quarter Horse and the Thoroughbred. Respondents reported that 40.2%, 28.9%, 24.0%, and 6.8% horses could be categorized as no exercise, light, moderate, or heavy/very heavy exercise, respectively. Of the horses exercised, 43% (120/278) were ridden recreationally (not used for competition). The median total minutes per week spent exercising for all horses was 180 min (IQR = 183). The average number of exercise sessions per week for all horses was 3.6 (SD = 2.2). Horses in heavy/ very heavy exercise (Mdn = 220, IQR = 272) and moderate exercise (Mdn = 180, IQR = 180) spent more minutes exercising per week compared with horses in light exercise (Mdn = 120, IQR = 180; P < 0.05). The total number of exercise sessions completed per week differed between horses in light (Mdn = 2, IQR = 3), moderate (Mdn = 4, IQR = 2), and heavy/ very heavy exercise (Mdn = 6, IQR = 2) (P < 0.05). According to the 2007 NRC, horses in light, moderate, and heavy/ very heavy exercise should spend 1–3, 3–4, and 4–5 h or more per week exercising, respectively. The current survey found horses placed in light, moderate, and heavy/ very heavy exercise spent 2, 3, and 3.7 h per week exercising, respectively. Equine caretakers’ perception of their horse's exercise intensity appeared to match the NRC exercise categories. This may not be indicative of the actual exercise workload, as self-reports can differ from actual management practices. In conclusion, this survey collected valuable information about how caretakers perceive the exercise workload of horses within Pennsylvania.
