Purpose: To determine (1) the time of arrival of peak blood lactate concentration ([BLa]peak) followed by various track events and (2) significant correlation, if any, between average velocity and [BLa]peak in these events. Methods: In 58 under-20 male track athletes, heart rate was recorded continuously and blood lactate concentration was determined at various intervals following 100-m (n = 9), 200-m (n = 8), 400-m (flat) (n = 9), 400-m hurdles (n = 8), 800-m (n = 9), 1500-m (n = 8), 3000-m steeplechase (n = 7), and 5000-m (n = 10) runs. Results: The [BLa]peak, in mmol/L, was recorded highest following the 400-m run (18.27 [3.65]) followed by 400-m hurdles (16.25 [3.14]), 800-m (15.53 [3.25]), 1500-m (14.71 [3.00]), 200-m (14.42 [3.40]), 3000-m steeplechase (11.87 [1.48]), 100-m (11.05 [2.36]), and 5000-m runs (8.65 [1.60]). The average velocity of only the 400-m run was found to be significantly correlated (r = .877, p < 0.05) with [BLa]peak. The arrival time of [BLa]peak following 100-m, 200-m, 400-m, 400-m hurdles, 800-m, 1500-m, 3000-m steeplechase, and 5000-m runs was 4.44 (0.83), 4.13 (0.93), 4.22 (0.63), 3.75 (0.83), 3.34 (1.20), 2.06 (1.21), 1.71 (1.44), and 1.06 (1.04) minutes, respectively, of the recovery period. Conclusion: In under-20 runners, (1) [BLa]peak is highest after the 400-m run, (2) the time of appearance of [BLa]peak varies from one event to another but arrives later after sprint events than longer distances, and (3) the 400-m (flat) run is the only event wherein the performance is significantly correlated with the [BLa]peak.
Subir Gupta, Arkadiusz Stanula, and Asis Goswami
Mário Esteves, Carina Silva, Sofia S. Pereira, Tiago Morais, Ângela Moreira, Madalena M. Costa, Mariana P. Monteiro, and José A. Duarte
Introduction: Benefits of regular physical exercise were demonstrated as preventive and coadjuvant nonpharmacological anticancer therapy. However, the role of exercise in modulating prostate cancer behavior has yet to be established. Methods: Prostate tumors were induced in C57BL/6 male mice (n = 28) by subcutaneous inoculation of a suspension of murine androgen-independent RM1 cells (1.5 × 105 cells/500 μL phosphate-buffered saline) in the dorsal region. Mice were randomly allocated into 2 study groups: sedentary tumor-induced (n = 14) and exercised tumor-induced (n = 14). Exercise consisted of voluntary running in wheeled cages. Mice (n = 7 per group) were sacrificed either 14 or 28 days after cell inoculation to evaluate tumor weight and percentage of area occupied by immunohistochemistry stained cells for Ki-67 and TdT-mediated dUTP-biotin nick end labeling, used as surrogate markers of cell proliferation and apoptosis, respectively. Results: Compared with sedentary tumor-induced mice, the tumors developed by exercised tumor-induced mice were significantly smaller at 14 days (0.17 [0.12] g vs 0.48 [0.24] g, P < .05) and at 28 days (0.92 [0.73] g vs 2.09 [1.31] g, P < .05), with smaller Ki-67 and greater TdT-mediated dUTP-biotin nick end-labeling stained areas (P < .05). Conclusion: These results suggest that regular voluntary running inhibits prostate cancer cell growth by reducing cell proliferation and enhancing apoptosis.
Colin B. Shore, Gill Hubbard, Trish Gorely, Angus M. Hunter, and Stuart D.R. Galloway
Background: Exercise referral schemes (ERS) aim to tackle noncommunicable disease via increasing levels of physical activity. Health benefits are reliant on uptake and attending ERS sessions. Hence, it is important to understand which characteristics may influence these parameters to target interventions to improve uptake and attendance to those who need it most. Method: Secondary analysis of one ERS database was conducted to (1) profile participants’ nonuptake of exercise referral; (2) describe any differences between nonattenders and attenders; and (3) report session count of attenders, exploring any relationship between attender demographics and session count. Results: The study showed that (1) sociodemographic profile of nonattenders was very similar to that of those who attended; (2) there was a high, early withdrawal rate of attenders wherein 68% exited the scheme at 5 exercise sessions or less; and (3) session count did not appear to differ by demographic characteristics. Conclusions: Nonattendance and session count did not appear to differ by demographic characteristics. Attendance at ERS was low. Nonuptake and reduced attendance may limit any associated health benefits that may be achieved from ERS. Therefore, it is important to identify additional factors that may influence participants’ choice to uptake and attend ERS.
Christianne F. Coelho-Ravagnani, Jeeser A. Almeida, Xuemei Sui, Fabricio C.P. Ravagnani, Russell R. Pate, and Steven N. Blair
Background: The effects of compliance with the US Physical Activity (PA) Guidelines and changes in compliance over time on cardiovascular disease (CVD) mortality are unknown. Methods: Male participants in the Aerobics Center Longitudinal Study (n = 15,411; 18–100 y) reported leisure-time PA between 1970 and 2002. The frequency of and time spent in PA were converted into metabolic equivalent minutes per week. The participants were classified into remained inactive, became active, became inactive, or remained active groups according to their achievement of the PA guidelines along the follow-up, equivalent here to at least 500 metabolic equivalent minutes of PA per week. Cox regression adjusted for different models was used for the analyses, using age, body mass index, smoking and drinking status, hypertension, diabetes, hypercholesterolemia, and parental history of CVD. Results: Over a mean follow-up of 6.2 years, 439 CVD deaths occurred. Consistently meeting the PA guidelines, compared with not meeting, was associated with a 54% (95% confidence interval, 0.32–0.67) decreased risk of CVD mortality. After controlling for all potential confounders, the risk reduction was 47% (95% confidence interval, 0.36–0.77). Conclusions: Maintaining adherence to the PA guidelines produces substantial reductions in the risk of CVD deaths in men. Furthermore, discontinuing compliance with the guidelines may offset the beneficial effects on longevity.
Nivash Rugbeer, Demitri Constantinou, and Georgia Torres
Background: High-intensity training is comprised of sprint interval training (SIT) and high-intensity interval training (HIIT). This study compared high-intensity training with moderate-intensity continuous training (MICT) on cardiorespiratory fitness (CRF) and body fat percentage for overweight or obese persons. Methods: A systematic search of randomized controlled trials using the health science databases occurred up to April, 2020. Twenty-six studies were included for complete analysis. A total of 784 participations were analyzed. The unstandardized mean difference for each outcome measurement was extracted from the studies and pooled with the random effects model. Results: MICT was significantly better at improving CRF compared with SIT (mean difference = −0.92; 95% confidence interval, −1.63 to −0.21; P = .01; I 2 = 10%). Furthermore, there was no significant difference between MICT versus HIIT on CRF (mean difference = −0.52; 95% confidence interval, −1.18 to 0.13; P = .12; I 2 = 23%). There was no significant difference in body fat percentage between MICT versus HIIT and MICT versus SIT. Conclusions: MICT was significantly better at improving CRF than SIT in overweight or obese persons.
Adi Weinberg, Nitzan Dror, Katya Motin, Michal Pantanowitz, Dan Nemet, and Alon Eliakim
Purpose: To examine the effect of growth hormone (GH) treatment on physical performance in children with idiopathic short stature and normal GH secretion. Materials and Methods: A total of 24 children participated in the study (13 GH-treated, 11 non-treated, aged 8–13 y, 11 males and 13 females, Tanner stage 1–2). Participants performed a battery of motor skill performance tests (Eurofit), as well as the Wingate anaerobic test. Results: No statistically significant differences in any of the Eurofit physical fitness test results (eg, 20-m shuttle run 33.0 [15.1] vs 25.1 [21.0] laps in treated and nontreated participants, respectively, P = .25) or the Wingate anaerobic test were found between the groups (eg, peak power 5.0 [2.9] vs 3.9 [2.6] watts/kg in treated and nontreated participants, respectively, P = .2). Conclusions: Therapeutic usage of exogenous GH for pre and early pubertal children with idiopathic short stature and normal GH secretion was not associated with beneficial effects on physical performance indices. This suggests that the use of GH as a potential performance enhancing agent, in this age group, at least at commonly used doses, is not advantageous.
Whitney N. Neal, Emma Richardson, and Robert W. Motl
The uptake and benefits of the Canadian Physical Activity Guidelines for Adults with Multiple Sclerosis (PAGs) have been validated, but there is limited understanding regarding the knowledge, needs, and preferences of people with multiple sclerosis (MS) for implementing the PAGs outside of clinical research. The authors conducted online, semistructured interviews with 40 persons with MS from across the United States seeking information on awareness of and potential approaches for increasing the uptake of the PAGs. They identified first impressions and potential approaches for increasing the uptake of the PAGs through inductive, semantic thematic analysis. Participants perceived the PAGs as a good introduction for structured exercise but desired more information on how to meet the PAGs. Participants further believed that modifying the PAGs for inclusivity and applying a multifaceted approach for dissemination and implementation may increase uptake of exercise behavior. Physical activity research in MS should include both analyzing the effects of exercise and the unique challenges faced by persons with MS in putting the PAGs into practice.
Frédéric Dierick, Fabien Buisseret, Loreda Filiputti, and Nathalie Roussel
The objective of this study was to explore the effects of static and dynamic hamstring muscles stretching on kinematics and esthetics of grand battement (high velocity kicks) in adolescent recreational dancers. Sixteen participants were assessed before and immediately after both stretching modalities. Kinematics of movement was measured by an optoelectronic system and esthetics was scored by a jury of professional dancers. Both stretching modalities led to significant kinematic differences compared with without stretching. Significant linear correlations between kinematic parameters and esthetic scores have been observed: improving dancers’ physical performances has noticeable impact on the perception of their movements.
João R. Pereira, Dylan P. Cliff, Eduarda Sousa-Sá, Zhiguang Zhang, Jade McNeill, Sanne L.C. Veldman, and Rute Santos
Background: This study aimed to understand whether a higher number of sedentary bouts (SED bouts) and higher levels of sedentary time (SED time) occur according to different day types (childcare days, nonchildcare weekdays, and weekends) in Australian toddlers (1–2.99 y) and preschoolers (3–5.99 y). Methods: The SED time and bouts were assessed using ActiGraph GT3X+ accelerometers. The sample was composed of 264 toddlers and 343 preschoolers. The SED bouts and time differences were calculated using linear mixed models. Results: The toddlers’ percentage of SED time was higher on nonchildcare days compared with childcare days (mean difference [MD] = 2.3; 95% confidence interval, 0.7 to 3.9). The toddlers had a higher number of 1- to 4-minute SED bouts on nonchildcare days compared with childcare days. The preschoolers presented higher percentages of SED time during nonchildcare days (MD = 3.1; 95% confidence interval, 1.6 to 4.5) and weekends (MD = 1.9; 95% confidence interval, 0.4 to 3.4) compared with childcare days. The preschoolers presented a higher number of SED bouts (1–4, 5–9, 10–19, and 20–30 min) during nonchildcare days and weekends compared with childcare days. No SED times or bout differences were found between nonchildcare days and weekends, neither SED bouts >30 minutes on toddlers nor on preschoolers. Conclusion: The SED time and bouts seem to be lower during childcare periods, which means that interventions to reduce sedentary time should consider targeting nonchildcare days and weekends.
Aashirwad Mahajan, Satish Mahajan, and Swanand Tilekar
The primary objective of this pilot randomized controlled trial was to study the feasibility (recruitment and retention rates) for interval training and sleep hygiene (SH) in adults aged above 60 years. Thirteen out of 46 screened individuals from a home for older adults in Shirdi (Maharashtra, India) were randomly assigned by permuted block randomization to either an interval training with SH group (n = 6) or an SH alone group (n = 7). The authors measured sleep with the S+ sleep monitor manufactured by ResMed (USA) Pittsburgh Sleep Quality Index and quality of life with Short Form-12 health survey version 2. Interval training consisted of 8 weeks of stationary cycling, whereas SH consisted of lecture and handouts. Recruitment was 38.2%, retention was >80% for both the interventions, and there was one loss to follow-up in SH. Interval training and SH were feasible for older adults and supported a full-scale randomized controlled trial.