Re-examination of 1- vs. 3-Sets of Resistance Exercise for Pre-spaceflight Muscle Conditioning: A Systematic Review and Meta-Analysis.

Background: Recommendations on resistance training (RT) set-volume protocols in preparation for spaceflight muscular strength conditioning remains equivocal. A meta-analysis was performed on the effects of single-set (S), or three-set (M3) RT on muscular strength per exercise for different body segments and joint types (multi-joint and single-joint). Methods: Computerized searches were performed on PubMed, MEDLINE and SPORTDiscus™. Twelve studies were considered appropriate according to pre-set eligibility criteria. Outcomes analyzed were pre-to-post-muscular strength change on; multi-joint and single-joint combined; upper body only; lower body only; multi-joint exercises only; single-joint exercises only. Results: Upper body exercise analysis on combined subjects and untrained subjects only reported greater but not significant strength gains with M3 (ES 0.37; 95% CI 0.09-0.82; P = 0.11 and ES 0.35; 95% CI-0.49 to 1.19; P = 0.42). Trained only subjects reported superior strength gains with M3 (ES 0.63; 95% CI 0.34-0.92; P = <0.0001). Lower body exercise on combined subjects and untrained subjects only reported superior strength gains with M3 (ES 0.35; 95% CI 0.10-0.60; P = 0.006 and ES 0.49; 95% CI 0.14-0.83; P = 0.005). Trained subjects only observed greater but not significant strength gains with M3 (ES 0.18; 95% CI -0.23 to 0.58; P = 0.39). Multi-joint exercise on combined subjects reported greater strength gains with M3 (ES 0.83; 95% CI 0.14-1.51; P = 0.02). Trained only subjects reported greater strength gains with M3 (ES 0.52; 95% CI 0.10-0.94; P = 0.02). Single-joint exercise on combined subjects and untrained only observed greater strength gains for M3 (ES 0.49; 95% CI 0.26-0.72; P = <0.0001 and ES 0.56; 95% CI 0.21-0.91; P = 0.002). Trained only subjects reported greater but not significant strength gains with M3 (ES 0.37; 95% CI -0.01 to 0.75; P = 0.06). Conclusion: For astronauts in space-flight preparation, the findings suggest that M3 training appears to be preferable over S for developing muscular strength. Nevertheless, depending on the physical conditioning of the crew member or tight pre-flight scheduling, S is still able to provide a positive strength training stimulus.

Weekly Training Frequency Effects on Strength Gain: A Meta-Analysis.

BACKGROUND: The current recommendations for resistance training (RT) frequency range from 2 to 5 days per week (days week- 1) depending on the subjects' training status. However, the relationship between RT frequency and muscular strength remains controversial with reported variances existing across different population groups. We conducted a meta-analysis that (1) quantified the effects of low (LF; 1 day week- 1), medium (MF; 2 days week- 1), or high (HF; ≥ 3 days week- 1) RT frequency on muscular strength per exercise; (2) examined the effects of different RT frequency on one repetition maximum (1RM) strength gain profiles (multi-joint exercises and single joint exercises); (3) examined the effects of different RT frequency on 1RM strength gain when RT volume is equated; and (4) examined the effects of different RT frequency on 1RM strength gains on upper and lower body. METHODS: Computerised searches were performed using the terms 'strength training frequency', 'resistance training frequency', 'training frequency', and 'weekly training frequency'. After review, 12 studies were deemed suitable according to pre-set eligibility criteria. Primary data were pooled using a random-effects model. Outcomes analysed for main effects were pre- to post strength change with volume-equated studies that combined multi-joint and isolation exercise; isolation-only exercise and untrained subjects only. Heterogeneity between studies was assessed using I2 and Cochran's Q statistics with funnel plots used to assess publication bias and sensitivity analyses calculated for subgroups. RESULTS: Pre- versus post-training strength analysis comprised of 74 treatment groups from 12 studies. For combined multi-joint and isolation exercises, there was a trend towards higher RT frequency compared with lower frequency [mean effect size (ES) 0.09 (95% CI - 0.06-0.24)] however not significant (p = 0.25). Volume-equated pre- to post-intervention strength gain was similar when LF was compared to HF [mean ES 0.03 (95% CI - 0.20-0.27); p = 0.78]. Upper body pre- to post-intervention strength gain was greater when HF was compared with LF [mean ES 0.48 (95% CI 0.20-0.76)] with significant differences between frequencies (p < 0.01). Upper body pre- to post-intervention strength gain was similar when MF was compared with LF (ES 0.12; 95% CI - 0.22-0.47); p = 0.48]. There was no significant difference in lower body mean ES between HF and LF [mean ES 0.21(95% CI - 0.55-0.13); p = 0.22]. There was a trend towards a difference in mean ES between MF and HF [mean ES 0.41(95% CI - 0.26-1.09); however, the effect was not significant (p = 0.23). CONCLUSIONS: The existing data does not provide a strong correlation between increased weekly training frequency (HF) and maximal strength gain in upper and lower body resistance exercises for a mixed population group. When RT is volume-equated for combined multi-joint and isolation exercises, there is no significant effect of RT frequency on muscular strength gain. More investigations are required to explore the effects of varying weekly training frequencies adequately.

Primary School Children's Health Behaviors, Attitudes, and Body Mass Index After a 10-Week Lifestyle Intervention With Follow-Up.

Background: Given the current global child obesity epidemic, testing the effectiveness of interventions in reducing obesity and its influencers is paramount. The purpose of this study was to determine immediate and long-term changes in body mass index and psychosocial variables following a 10-week lifestyle intervention. Methods: Seven hundred and seventy participants (8.75 ± 0.98 years of age, 379 boys and 391 girls) took part in the study. Participants had height, weight, and psychosocial questionnaires assessed at pre- and post-control, pre- and post-intervention, and 6-months post-intervention. Participants completed a weekly 10-week intervention consisting of healthy eating and physical activity education, physical activity, parental involvement, and behavior change techniques. Regression models were fit with correlated errors where the correlation occurred only between time points, not between subjects, and the nesting effects of school and area deprivation were controlled. Results: Regression models revealed a significant decrease in body mass index from pre- to post-intervention of 0.8512 kg/m2 (P = 0.0182). No Changes in body mass index occurred from post-intervention to 6-month follow-up (P = 0.5446). The psychosocial variables did not significantly change. Conclusions: This lifestyle intervention may be an effective means for improving body mass index in primary school children in the short-term if the duration of the intervention is increased, but these changes may not be sustained without on-going support.

The Effect of Weekly Set Volume on Strength Gain: A Meta-Analysis.

BACKGROUND: Strength training set organisation and its relationship to the development of muscular strength have yet to be clearly defined. Current meta-analytical research suggests that different population groups have distinctive muscular adaptations, primarily due to the prescription of the strength training set dose. OBJECTIVES: We conducted a meta-analysis with restrictive inclusion criteria and examined the potential effects of low (LWS), medium (MWS) or high weekly set (HWS) strength training on muscular strength per exercise. Secondly, we examined strength gain variations when performing multi-joint or isolation exercises, and probed for a potential relationship between weekly set number and stage of subjects' training (trained versus untrained). METHODS: Computerised searches were performed on PubMed, MEDLINE, SWETSWISE, EMBASE and SPORTDiscus™ using the terms 'strength training', 'resistance training', 'single sets', 'multiple sets' and 'volume'. As of September 2016, 6962 potentially relevant studies were identified. After review, nine studies were deemed eligible per pre-set inclusion criteria. Primary data were pooled using a random-effect model. Outcomes for strength gain, strength gain with multi-joint and isolation exercise were analysed for main effects. Sensitivity analyses were calculated for several subgroups by separating the data set and by calculation of separate analyses for each subgroup. Heterogeneity between studies was assessed using the Cochran Q and I 2 statistics. RESULTS: Pre- versus post-training strength analysis comprised 61 treatment groups from nine studies. For combined multi-joint and isolation exercises, pre- versus post- training strength gains were greater with HWS compared with LWS [mean effect size (ES) 0.18; 95% CI 0.06-0.30; p = 0.003]. The mean ES for LWS was 0.82 (95% CI 0.47-1.17). The mean ES for HWS was 1.01 (95% CI 0.70-1.32). Separate analysis of the effects of pre- versus post-training strength for LWS or MWS observed marginally greater strength gains with MWS compared with LWS (ES 0.15; 95% CI 0.01-0.30; p = 0.04). The mean ES for LWS was 0.83 (95% CI 0.53-1.13). The mean ES for MWS was 0.98 (95% CI 0.62-1.34). For multi-joint exercises, greater strength gains were observed with HWS compared with LWS (ES 0.18; 95% CI 0.01-0.34; p = 0.04). The mean ES for LWS was 0.81 (95% CI 0.65-0.97). The mean ES for HWS was 1.00 (95% CI 0.77-1.23). For isolation exercises, greater strength gains were observed with HWS compared with LWS (ES 0.23; 95% CI 0.06-0.40; p = 0.008). The mean ES for LWS was 0.95 (95% CI 0.30-1.60). The mean ES for HWS was 1.10 (95% CI 0.26-1.94). For multi-joint and isolation exercise-specific one repetition maximum (1 RM), marginally greater strength gains were observed with HWS compared with LWS (ES 0.14; 95% CI -0.01 to 0.29; p = 0.06). The mean ES for LWS was 0.80 (95% CI 0.47-1.13). The mean ES for HWS was 0.97 (95% CI 0.68-1.26). CONCLUSION: This meta-analysis presents additional evidence regarding a graded dose-response relationship between weekly sets performed and strength gain. The use of MWS and HWS was more effective than LWS, with LWS producing the smallest pre- to post-training strength difference. For novice and intermediate male trainees, the findings suggest that LWSs do not lead to strength gains compared with MWS or HWS training. For those trainees in the middle ground, not a novice and not advanced, the existing data provide a relationship between weekly sets and strength gain as set configurations produced different pre- to post-training strength increases. For well trained individuals, the use of either MWS or HWS may be an appropriate dose to produce strength gains.

The Relationship Between Aerobic and Anaerobic Performance in Recreational Runners.

Research has indicated that combined aerobic and anaerobic training (concurrent training) may improve aerobic performance greater than aerobic training alone. The purpose of this investigation was to establish any associations between aerobic and anaerobic performance. Eleven participants (n = 11, age = 34.1 ± 13 years, VO2max = 58.4 ± 7.8) volunteered for this study. Participants were asked for endurance training experience (4.7 ± 3.7 years) and resistance training experience (4.1 ± 4.6 years). To meet training status, participants were to have a VO2max in the 80th percentile as per ACSM guidelines. The Bruce treadmill test was used to measure aerobic performance. In order to measure anaerobic performance, several tests were completed utilizing a force platform. A Pearson Product R Correlation Coefficient was calculated to determine correlations between variables. The results show significant correlation between VO2max and RFD (r = 0.68). Further analyses utilizing Cohen's effect size indicated a strong association between VO2max and peak force, as well as running efficiency and peak power, relative peak power, and power endurance. These results indicate an existing possibility that anaerobic performance measures such as RFD may have a positive relationship with aerobic performance measures such as VO2max. Therefore, it may be beneficial to integrate specific training components which focus on improving RFD as a method of improving running performance.

A Systematised Review of Primary School Whole Class Child Obesity Interventions: Effectiveness, Characteristics, and Strategies.

Background. A systematised review was conducted to examine the effectiveness of school-based interventions that focus on changing dietary intake and physical activity levels to reduce childhood obesity. Methods. Multiple databases were searched for randomised and nonrandomised interventions from 2007 to 2016 in full-time elementary schools, which were delivered to the whole class, included dietary and physical activity components, involved both sexes, were written in English, and used body mass index (BMI) as an outcome. Results. The database search produced 8,866 titles from which 78 were deemed relevant and assessed for inclusion resulting in 15 studies meeting all inclusion criteria. From these 15 studies, 9 yielded a reduction or stabilisation in BMI or BMI z-score in the entire intervention group and/or subgroups. Programmes lasting between 6 and 12 months that involve multiple environmental, educational, and physical strategies appear to be most likely to result in BMI or BMI z-score improvement. Moderators most likely influencing an improvement in BMI included increased physical activity, decreased sugar sweetened beverages intake, and increased fruit intake. Conclusions. School-based interventions may be an effective means for child obesity prevention. The identification of consistent elements used in school-based interventions that have demonstrated effectiveness may aid in preventing child obesity.

Cardiovascular responses to isometric hand grip vs. relaxed hand grip in sustained cycling efforts.

Peripheral isometric contractions may lead to enhanced performance. Previous research using hand grip protocols indicates increased stabilization and peak power outputs. Research is lacking with the grip vs. no-grip protocol during sustained efforts. The purpose of this study is to determine cardiovascular reactions (i.e., heart rate [HR], blood pressure [BP], and rate pressure product [RPP]) during sustained cycling via an isometric and relaxed hand grip. Nine (n = 9) recreational cyclists participated in this study. After signing a medical and physical readiness questionnaire, the subjects were randomly assigned to 1 of 2 different protocols. Preexercising values of the HR (beats per minute), BP (miilimeters of mercury), height (centimeters), weight (kilograms), and age (years) were assessed before testing. A Monark bicycle ergometer was used for testing. Grip was substantiated through the use of a hand grip dynamometer at 20 kg of tension. Protocol 1 used an isometric "Hand Grip" scenario at 150 W for 20 minutes. Protocol 2 used a "Relaxed Hand Grip" at the same power and time. During the 20-minute exercise test, HR (POLAR), BP (stethoscope and sphygmomanometer), and calculated RPP (HR × systolic BP [SPB]/100) were recorded every minute. Statistical measures included mean and SDs between protocols, and dependent samples t-tests were used to examine differences between grip and no-grip protocols. At an alpha of ≤0.05, SBP did show a significant increase when using no grip, 161.4 (5.1) mm Hg vs. grip, 154.1 (6.6) mm Hg. However, rate pressure product and heart rate showed no significant differences between protocols. Our data suggested that the use of an isometric hand grip is transient and diminishes over time.

Implementing a mathematical model to compare oxygen uptake kinetics between cyclists and noncyclists during steady state.

The purpose was to compare a mathematical model of oxygen uptake and bioenergetic systems to an experimental protocol. Twelve (N = 12) noncyclists (NC), age (21.8 ± 1.4 years), and 8 (N = 8) cyclists (C), age (30.5 ± 5.7 years), were subjects. All subjects signed an informed consent. Oxygen consumption (VO2, ml·kg⁻¹·min⁻¹) was measured with steady-state VO2 requirements and responses determined using the mathematical model from the following equation: VO2 (WR) = VO2 (rest) + VO2 (unloading pedaling) + α.WR; ΔVO2(t, WR) = ΔVO2 (WR) = [1-e[-(t-td)/tO2]. Exercise means (SD) included the following: VO2NC(WR) = 48.4 (16.6) ml⁻¹·min⁻¹ for NCs and VO2C(WR) = 56.4 (24.95) ml⁻¹·min⁻¹ for Cs ; ΔVO2C(t, WR) = 6:38 ml⁻¹·min⁻¹ for NCs and ΔVO2C(t, WR) = 7.44 ml⁻¹·min⁻¹ for Cs. The correlation between the mathematical model and actual measure was statistically significant (p < 0.01) with a coefficient of r = 0.947. The experimental protocol was significantly associated with the mathematical model. This allows for a quantitative analysis and safe prediction of steady-state oxygen uptake conditions on populations before exposure to exercising conditions. Through more precise analysis of conditions, greater specificity of training may lead to more predictable adaptation outcomes.

Determination of ventilatory threshold through quadratic regression analysis.

Ventilatory threshold (VT) has been used to measure physiological occurrences in athletes through models via gas analysis with limited accuracy. The purpose of this study is to establish a mathematical model to more accurately detect the ventilatory threshold using the ventilatory equivalent of carbon dioxide (VE/VCO2) and the ventilatory equivalent of oxygen (VE/Vo2). The methodology is primarily a mathematical analysis of data. The raw data used were archived from the cardiorespiratory laboratory in the Department of Kinesiology at Midwestern State University. Procedures for archived data collection included breath-by-breath gas analysis averaged every 20 seconds (ParVoMedics, TrueMax 2400). A ramp protocol on a Velotron bicycle ergometer was used with increased work at 25 W.min beginning with 150 W, until volitional fatigue. The subjects consisted of 27 healthy, trained cyclists with age ranging from 18 to 50 years. All subjects signed a university approved informed consent before testing. Graphic scatterplots and statistical regression analyses were performed to establish the crossover and subsequent dissociation of VE/Vo2 to VE/VCO2. A polynomial trend line along the scatterplots for VE/VO2 and VE/VCO2 was used because of the high correlation coefficient, the coefficient of determination, and trend line. The equations derived from the scatterplots and trend lines were quadratic in nature because they have a polynomial degree of 2. A graphing calculator in conjunction with a spreadsheet was used to find the exact point of intersection of the 2 trend lines. After the quadratic regression analysis, the exact point of VE/Vo2 and VE/VCO2 crossover was established as the VT. This application will allow investigators to more accurately determine the VT in subsequent research.

Preadolescent male perceptions of action figure physiques.

This study investigated the preference and reasoning of 176 preadolescent and adolescent males when presented with original and current action figures that had statistically different physiques. Current action figures were perceived as significantly more muscular and healthier. Participants also preferred to resemble current action figures citing muscularity and size for their preference.

Noninvasive profiling of exercise-induced hypoxemia in competitive cyclists.

The purpose of this case study was to profile maximal exercise and the incidence of exercise-induced arterial hypoxemia (EIAH) at three different altitudes within a group of competitive cyclists residing and training at 1,500 m. Ten male cyclists (category I or II professional road cyclists: ages, 27.7 +/- 6.1; weight, 69.9 +/- 6.9 kg) participated in three randomly assigned VO2max tests at sea level (SL), 1,500 m and 3000 m. Arterial saturation (pulse oximetry), ventilation, and power output (PO) were recorded continuously throughout the test. The SaO2 percentages at VO2max were significantly higher at SL when compared with 1500 m (p < 0.001); however, no difference was observed between VO2max values at either altitude (SL: 72.3 +/- 2.5 mL.kg-1.min-1, 1,500 m: 70.6 +/- 2.3 mL.kg-1.min-1), only when compared with 3,000 m: 63.9 +/- 2.1 mL.kg-1.min-1, p < 0.021. Percent SaO2 did correspond with maximal PO, and there was an overall main effect observed between POs as they continually declined from SL to 3,000 m (SL: 403.3 +/- 10.6 W; 1,500 m: 376.1 +/- 9.8 W; 3,000 m: 353.9 +/- 7.8 W; p < 0.0001). The results of this case study revealed that training and residing at 1,500 m did not reduce the incidence of EIAH during maximal exercise at 1,500 m for this selected group of cyclists.

Cordyceps sinensis- and Rhodiola rosea-based supplementation in male cyclists and its effect on muscle tissue oxygen saturation.

Cordyceps sinensis (Cs) and Rhodiola rosea (Rr) are herbs used in traditional Chinese medicine to treat a multitude of ailments as well as to enhance performance. The purpose of this research was to examine the effects of a formula containing Cs and Rr (Cs-Rr) on circulatory dynamics, specifically muscle tissue oxygen saturation (Sto(2)), in male subjects during maximal exercise. This study followed a double blind, randomized, placebo-treatment, pre-post test design. Capsules were administered to 8 subjects who were randomly assigned to 1 of 2 groups. The treatment group received Cs-Rr, and the control group received a placebo. All subjects performed 2 exercise stress tests to volitional fatigue on a cycle load ergometer. There were no significant (p

Homocysteine and vascular access thrombosis in a cohort of end-stage renal disease patients.

BACKGROUND: Maintaining successful hemodialysis services is dependent upon an access to circulation that is reliable and stable. Complications of vascular access such as dysfunction, thrombosis, or infection are major causes of hospitalization with thrombosis being the most common reoccurring problem. Initial prospective evidence supports an independent association between total homocysteine (tHcy) levels and access thrombosis. The purpose of this study was to determine if significant associations exist between tHcy, age, gender, and vascular access thrombosis in patients with end-stage renal disease (ESRD). SUBJECTS AND METHODS: One hundred eighty-five (N=185) patients undergoing dialysis were selected as subjects. The retrospective sample was divided into a one or less vascular access thrombosis (VAT) (VAT) group (n= 133) and more than one (VAT II) VAT group (n= 52). The data was collected during a 16-month period (January 2000 to April 2002). Additional subgroup analyses included gender and age. RESULTS: The Mann-Whitney U nonparametric t-Test for variance between groups revealed no significant difference in tHcy values between VAT groups (U=1841.50, p=0.284). A two-sample t-Test for variance between tHcy and age revealed no significant differences (F-ratio = 0.832, p = 0.32). A chi-square analysis revealed no significant differences in gender and VAT groups (chi2=0.246, p=0.62). A Kolmogorov-Smirnov test for normality was calculated for tHcy with a p-value of 0.859 revealing insufficient evidence that the distribution is not normal. Spearman Rank Correlations were calculated, revealing low to moderate associations among variables. CONCLUSIONS: While some studies have demonstrated a relationship between tHcy and VAT, this study found that chronically high homocysteine levels in patients with ESRD were not associated with incidence of VAT. There were no significant differences in the number of VATs across additional variables of age and gender.

Homocysteine and vascular access thrombosis in end-stage renal disease patients: a retrospective study.

BACKGROUND: Though pathology in end-stage renal disease (ESRD) patients with high total homocysteine (tHcy) can be established, the research findings with vascular access thrombosis (VAT) and tHcy are equivocal. Investigators have found significantly higher homocysteine levels in patients with recurrent VAT compared with one or less episodes of thrombosis. Initial prospective evidence supports an independent association between tHcy levels and access thrombosis. METHODS: One hundred and four patients undergoing dialysis were selected. The experimental group participants were identified as those having one or more vascular access thromboses (VAT) during the previous 14-month period (November 2000 to January 2002) and the control group participants were those with no VAT during the same period. Additional sub-group analyses included the following: a) hypertensive vs. normotensive; b) diabetes mellitus, Type I, Type II, and none; c) gender; d) age. RESULTS: The Mann-Whitney U test for variance revealed no significant difference in tHcy values between VAT groups (U = 1580.5, p = 0.075), no significant differences in VAT and hypertension (U = 1009.0, p = 0.70), and no significant differences in VAT and Diabetes Mellitus (U = 1254.5, p = 0.67). A two-sample t-Test revealed no significant differences in tHcy and age (F-ratio = 1.26, p = 0.47). A Kolmogorov Smirnov test for normality revealed insufficient evidence that the tHcy distribution is not normal. Spearman Rank Correlations were calculated revealing low to moderate associations among variables. CONCLUSIONS: While some studies have demonstrated a relationship between tHcy and VAT, this study found chronically high homocysteine levels in patients with ESRD were not associated with incidence of VAT. There were no significant differences in the number of VAT's across additional variables of age, gender, and previous morbidity. No significant interactions were discovered.