Short-term Creatine Supplementation Improves Maximum Quadriceps Contraction in Women

2003 ◽  
Vol 13 (1) ◽  
pp. 87-96 ◽  
Author(s):  
Kenneth W. Kambis ◽  
Sarah K. Pizzedaz
Keyword(s):  
Body Weight ◽  
Muscle Function ◽  
Muscle Power ◽  
Average Power ◽  
Creatine Supplementation ◽  
Time Of Day ◽  
Fat Free Mass ◽  
Muscle Performance ◽  
Testing Procedures ◽  
Post Test

Creatine monohydrate (CrH2O) supplementation has been demonstrated to increase skeletal muscle power output in men. However, its effect upon women is not as clearly defined. This study investigated the effect of oral creatine supplementation upon muscle function, thigh circumference, and body weight in women. Twenty-two consenting college-age women were assigned to 1 of 2 groups matched for dietary and exercise habits, phase of menstrual cycle, and fat-free mass (FFM). After familiarization with testing procedures, pretrial measures of muscle function (5 repetitions 60 deg · s−1 and 50 repetitions 180 deg · s−1) were conducted during maximal voluntary concentric contraction of the preferred quadriceps muscle using an isokinetic dynamometer. Subjects then ingested 0.5 g · kg−1 FFM of either CrH2O or placebo (one fourth dosage 4 times daily) in a double-blind design for 5 days. Resistance exercise was prohibited. After the ingestion phase was completed, all measures were repeated at the same time of day as during pretrials. Statistical analysis revealed time to peak torque in quadriceps extension decreased from pre-test values of 255 ± 11 ms (mean ± SEM) to post-test values of 223 ± 3 ms; average power in extension increased from 103 ± 7 W pre-test to 112 ± 7 W post-test; and, during flexion, average power increased from 59 ± 5 W pre-test to 65 ± 5 W post-test in the creatine group as compared to controls (p ≤ .05). FFM, percent body fat, mid-quadriceps circumference, skinfold thickness of the measured thigh, and total body weight did not change for both groups between trials. We conclude that CrH2O improves muscle performance in women without significant gains in muscle volume or body weight.

scholarly journals Share of Strength Parameters of Bench Press and Barbell Bench Pull on a Horizontal Bench in Sports Performance in Kayak Disciplines

2021 ◽  
Vol 21 (1) ◽  
pp. 90-95
Author(s):  
Jaroslav Broďáni ◽  
Natália Dvořáčková ◽  
Monika Czaková ◽  
Zdenek Malík ◽  
Peter Lopata
Keyword(s):  
Bench Press ◽  
Muscle Power ◽  
Average Power ◽  
Transformation Process ◽  
Maximum Power ◽  
Muscle Performance ◽  
Sports Performance ◽  
Strength Parameters ◽  
Team Members ◽  
National Team

The objective of the study was to deal with the ratio of the parameters of maximum muscle power and power endurance and explain their contribution to the sports performance in kayak disciplines of Slovakia National Team members. Material and methods. Strength parameters were monitored by Tendo Power Analyser in the barbell bench press and pull on a horizontal bench. A diagnostic series of maximum power and effective repetition test for power endurance was performed at both, barbell bench press and bench pull exercises. Determining the factors limiting sports performance in kayak disciplines 200 meters, 500 meters, 1,000 meters, 5,000 meters, and marathon 21,500 meters, the evaluation of dependence between all power variables were used. The stepwise regression was used to reduce the indicators.  Results. It was found out that in kayak sprint disciplines (200 meters, 500 meters) the sports performance in the kayak is influenced by the barbell bench pull more than bench press on the horizontal bench when speaking about the strength parameters. In the middle-distance disciplines (1,000 meters), the ratio of strength parameters is balanced. As the length of kayak disciplines increases (5,000 meters and 21,500 meters), the ratio of strength parameters has changed in favor of the barbell bench press. From the parameters of maximum muscle performance and muscle endurance measured in the barbell bench press and pull on a horizontal bench, the average power of power endurance was demonstrated to explain the sports performance in kayak disciplines.  Conclusion. From the parameters of maximum power and power endurance in the bench press and bench pull in all kayak disciplines, the parameter of average power in power endurance was proved to explain sports performance. Knowledge of these factors will allow optimizing the content of sports training of kayakers, the process of developing their strength skills, and their transformation process into a structure of sports performance and kayaking paddling technique. 

scholarly journals Dynamics of Muscular Performance Indices during the 30‑s Vertical Jump Test in Endurance and Sprint Cohorts

2018 ◽  
Vol 4 (83) ◽  
Author(s):  
Eugenijus Trinkūnas ◽  
Alfonsas Buliuolis ◽  
Rita Sadzevičienė ◽  
Birutė Zacharienė
Keyword(s):  
Muscle Power ◽  
Vertical Jump ◽  
Muscle Performance ◽  
Performance Indices ◽  
Testing Procedures ◽  
Muscular Performance ◽  
Assessment Tests ◽  
Jump Test ◽  
Endurance Runners ◽  
The Difference

Research background and hypothesis. According the methodological requirement testing procedures do not modify the main training objectives. It is well known that specificity of performance assessment tests is important if we want to compare performance of different groups tested.Research aim was to find out the peculiarities of muscular performance indices in sprint and endurance cohorts while performing a 30-s vertical jump test.Research methods. The participants of the study were two groups of athletes, i. e. sprint and endurance runners. The participants of the study performed a 30-s vertical jumps test with maximal efforts. The sum of height of all jumps was calculated by a special computerized program and the values in height of jumps, contact time and relative power at onset of workload and at each 5 seconds of the test were analyzed.Research results. The difference between the cohorts in jumps height was statistically significant (p < 0.05) during the whole series of jumps. Athletes’ adaptation to speed-power type of exercising produced higher anaerobic muscle performance indices while performing 30-s duration jumps test. Endurance runners usually demonstrate lower results in jumping than sprint- athletes and they compensate reduced muscular power with prolonged duration of take-off.Discussion and conclusions. Despite some methodological limitations the results of this study show that the assessment of muscular performance indices allows assessing the peculiarities of dynamics of relative muscle power and fatigue.Keywords: endurance and sprint running, muscular performance, vertical jump test.

Long-term creatine intake is beneficial to muscle performance during resistance training

1997 ◽  
Vol 83 (6) ◽  
pp. 2055-2063 ◽  
Author(s):  
K. Vandenberghe ◽  
M. Goris ◽  
P. Van Hecke ◽  
M. Van Leemputte ◽  
L. Vangerven ◽  
...  
Keyword(s):  
Resistance Training ◽  
Muscle Strength ◽  
Exercise Capacity ◽  
Low Dose ◽  
Intermittent Exercise ◽  
Creatine Supplementation ◽  
Fat Free Mass ◽  
Muscle Performance ◽  
High Dose

Vandenberghe, K., M. Goris, P. Van Hecke, M. Van Leemputte, L. Vangerven, and P. Hespel. Long-term creatine intake is beneficial to muscle performance during resistance training. J. Appl. Physiol. 83(6): 2055–2063, 1997.—The effects of oral creatine supplementation on muscle phosphocreatine (PCr) concentration, muscle strength, and body composition were investigated in young female volunteers ( n = 19) during 10 wk of resistance training (3 h/wk). Compared with placebo, 4 days of high-dose creatine intake (20 g/day) increased ( P < 0.05) muscle PCr concentration by 6%. Thereafter, this increase was maintained during 10 wk of training associated with low-dose creatine intake (5 g/day). Compared with placebo, maximal strength of the muscle groups trained, maximal intermittent exercise capacity of the arm flexors, and fat-free mass were increased 20–25, 10–25, and 60% more ( P < 0.05), respectively, during creatine supplementation. Muscle PCr and strength, intermittent exercise capacity, and fat-free mass subsequently remained at a higher level in the creatine group than in the placebo group during 10 wk of detraining while low-dose creatine was continued. Finally, on cessation of creatine intake, muscle PCr in the creatine group returned to normal within 4 wk. It is concluded that long-term creatine supplementation enhances the progress of muscle strength during resistance training in sedentary females.

Some consequences of body size

1984 ◽  
Vol 247 (4) ◽  
pp. H495-H507 ◽  
Author(s):  
L. E. Ford
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Metabolic Rate ◽  
Muscle Power ◽  
Weight Ratio ◽  
Single Species ◽  
Hill Climbing ◽  
Proper Size ◽  
Higher Power ◽  
Metabolic Indices

The question of the proper size denominator for metabolic indices is addressed. Metabolic rate among different species is proportional to the 3/4 power of body weight, not surface area. Muscle power also varies with the 3/4 power of weight, suggesting that metabolic rate is determined mainly by muscle power. Power-to-weight ratio, specific metabolic rate, and a number of metabolic periods, including heart rate, all vary inversely with the 1/4 power of body weight. Thus the relative times required for physiological and pathological processes in different species may be estimated from the average resting heart rate for the species. There are not many small humans among athletic record holders in events involving acceleration and hill climbing, as would be expected if they had higher power-to-weight ratios. Thus the relationship between size and metabolic rate in different species should not be applied within the single species of humans. Evidence is reviewed showing that basal metabolic rate in humans is determined mainly by lean body mass.

scholarly journals Acute Effects of Different Postactivation Potentiation Protocols on Traditional Rowing Performance

2020 ◽  
Vol 18 (1) ◽  
pp. 80
Author(s):  
Alfonso Penichet-Tomas ◽  
Jose M. Jimenez-Olmedo ◽  
Luis Serra Torregrosa ◽  
Basilio Pueo
Keyword(s):  
Effect Size ◽  
Muscle Power ◽  
Average Power ◽  
Postactivation Potentiation ◽  
Warm Up ◽  
Maximal Load ◽  
Rowing Performance ◽  
Load Intensity ◽  
And Performance ◽  
Student’S T

Postactivation potentiation (PAP) describes an initial muscular activation with a submaximal or maximal load intensity that produces acute improvements in muscle power and performance in subsequent explosive activities. The objective of this study was to compare the effect of different PAP protocols in rowing performance. A crossover design involving seven rowers was used, in which two different PAP protocols were applied: PAP of maximal conditioning contractions (PAP MCC) on a rowing ergometer to provide greater transferability and, thus, enhance the magnitude of PAP stimuli on subsequent rowing performance; and PAP of maximal strength contractions (PAP MSC) in half squat and bench pull exercises, similar to the main exercises in rowing strength training, to perform a 20 s “all-out” test simulating a competition start. Student’s t-test was used to compare means of the variables (p < 0.05). Effect size statistics were calculated using Cohen’s d. The PAP MCC protocol resulted in significant differences, with an extremely large effect size in average power output (p = 0.034, d = 0.98) in the first 3 (p = 0.019, d = 1.15) and first 5 (p = 0.036, d = 0.91) strokes. This group also reached a greater number of strokes (p = 0.049, d = 2.29) and strokes per minute (p = 0.046, d = 1.15). PAP with maximal conditioning contractions in rowing warm-up enhanced subsequent rowing sprint and is an advisable strategy to potentiate performance at the start of rowing competitions and sprint regattas.

Body Composition Modifications Due to the “Search, Rescue and Survival Training” in Male Military Firefighter Cadets

2021 ◽  
Author(s):  
Thiago Ramos de Barros ◽  
Verônica Pinto Salerno ◽  
Thalita Ponce ◽  
Míriam Raquel Meira Mainenti
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Repeated Measures ◽  
Food Restriction ◽  
Physical Exertion ◽  
High Energy ◽  
The Body ◽  
Fat Free Mass ◽  
Sleep Restriction ◽  
Fat Percentage

ABSTRACT Introduction To train and prepare cadets for a career as firefighters in Rio de Janeiro, the second-year students of the Officers Training Course are submitted to a Search, Rescue, and Survival Training (SRST) course, which is characterized by long periods of high physical exertion and sleep restriction during a 9-day instruction module, and food restriction during a 7-day survival module. The present study investigated changes in the body composition of 39 male cadets submitted to SRST during training and 4 weeks of recovery with no restrictions in food consumption. Materials and Methods Each cadet was evaluated by anthropometric measurements at six time points: pre-SRST; after the first module; after the second module; and after 1, 2, and 4 weeks of recovery. Measurements included body girths and skinfolds, to estimate trunk (chest and waist) and limbs (arm and thigh) dimensions, as well as body composition. Repeated measures ANOVA and Friedman test were applied (depending on each data distribution). Results Statistically significant decreases in body weight (76.2; 69.8-87.2 to 63.9; 58.9-73.5 kg) and fat free mass (FFM, 69.2; 63.7-77.2 to 60.1; 56.2-68.0 kg) were observed following the second module of SRST. Following a single week of recovery, the FFM returned to pre-SRST values. Body weight returned to pre-training levels in 2 weeks. Body fat percentage and mass also significantly decreased during SRST (9.0; 7.7-12.3 to 6.5; 5.1-9.3% and 6.9; 5.6-10.0 to 6.9; 5.6-10.0 kg, respectively), which showed a slower and more gradual recovery that reached pre-SRST values after 4 weeks. The girths of arm, thigh, chest and waist significantly decreased due to SRST. The girths of the limbs (arm and thigh) returned to pre-training values after one month of recovery, while the girths of the trunk (chest and waist) did not return to pre-SRST values during the study period. Conclusions The findings suggest that men who experience periods of high energy demands and sleep restriction followed by a period of food restriction will endure unavoidable physical consequences that can be mostly reversed by a 1-month recovery.

The Influence of Age, Sex and Body Mass Index on the Effectiveness of Brisk Walking for Obesity Management in Adults: A Systematic Review and Meta-Analysis

2017 ◽  
Vol 14 (5) ◽  
pp. 389-407 ◽  
Author(s):  
Leon Mabire ◽  
Ramakrishnan Mani ◽  
Lizhou Liu ◽  
Hilda Mulligan ◽  
David Baxter
Keyword(s):  
Body Mass Index ◽  
Body Weight ◽  
Waist Circumference ◽  
Body Fat ◽  
Fat Mass ◽  
Fat Free Mass ◽  
Body Fat Percentage ◽  
Brisk Walking ◽  
Obesity Management ◽  
Fat Percentage

Background:Brisk walking is the most popular activity for obesity management for adults. We aimed to identify whether participant age, sex and body mass index (BMI) influenced the effectiveness of brisk walking.Methods:A search of 9 databases was conducted for randomized controlled trials (RCTs). Two investigators selected RCTs reporting on change in body weight, BMI, waist circumference, fat mass, fat-free mass, and body fat percentage following a brisk walking intervention in obese adults.Results:Of the 5072 studies screened, 22 met the eligibility criteria. The pooled mean differences were: weight loss, –2.13 kg; BMI, –0.96 kg/m2; waist circumference, –2.83 cm; fat mass, –2.59 kg; fat-free mass, 0.29 kg; and body fat percentage, –1.38%. Meta-regression of baseline BMI showed no effect on changes.Conclusions:Brisk walking can create a clinically significant reduction in body weight, BMI, waist circumference, and fat mass for obese men and women aged under 50 years. Obese women aged over 50 years can achieve modest losses, but gains in fat-free mass reduce overall change in body weight. Further research is required for men aged over 50 years and on the influence of BMI for all ages and sexes.

scholarly journals Effect of Acute Ramadan Fasting on Muscle Function and Buffering System of Male Athletes

Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 397
Author(s):  
Mohamad Fashi ◽  
Sajad Ahmadizad ◽  
Hadi Nobari ◽  
Jorge Pérez-Gómez ◽  
Rafael Oliveira ◽  
...  
Keyword(s):  
Muscle Function ◽  
Venous Blood ◽  
Average Power ◽  
Peak Torque ◽  
Buffering Capacity ◽  
Gas Analyzer ◽  
Borg Scale ◽  
Male Athletes ◽  
Ramadan Fasting ◽  
Blood Gas Analyzer

The aim of this study was to investigate the effect of acute Ramadan fasting (RF) on the muscle function and buffering system. Twelve male athletes with 8 years of professional sports experience (age, 23.2 ± 1.3 years, body mass index: 24.2 ± 2.2 kg/m2) participated in this study. The subjects were tested twice, 3 weeks after the beginning of RF and 2 weeks after the end RF. Muscle function, buffering capacity, and rating of perceived exertion (RPE) were measured during and after RF by using the Biodex isokinetic machine, blood gas analyzer, and RPE 6–20 Borg scale, respectively. Venous blood samples for pH and bicarbonate (HCO3−) were measured during and after RF by using the Biodex isokinetic machine, blood gas analyzer, and RPE 6–20 Borg scale, respectively. Venous blood samples for pH and bicarbonate (HCO3−) were taken immediately after 25 repetitions of isokinetic knee flexion and extension. Measures taken during isokinetic knee extension during RF were significantly lower than those after RF in extension peak torque (t = −4.72, p = 0.002), flexion peak torque (t = −3.80, p = 0.007), extension total work (t = −3.05, p = 0.019), extension average power (t = −4.20, p = 0.004), flexion average power (t = −3.37, p = 0.012), blood HCO3− (t = −2.02, p = 0.041), and RPE (Z = −1.69, p = 0.048). No influence of RF was found on the blood pH (t = 0.752, p = 0.476). RF has adverse effects on muscle function and buffering capacity in athletes. It seems that a low-carbohydrate substrate during RF impairs muscle performance and reduces the buffering capacity of the blood, leading to fatigue in athletes.

scholarly journals Body composition and energy intake — skeletal muscle mass is the strongest predictor of food intake in obese adolescents: The HEARTY trial

2016 ◽  
Vol 41 (6) ◽  
pp. 611-617 ◽  
Author(s):  
Jameason D. Cameron ◽  
Ronald J. Sigal ◽  
Glen P. Kenny ◽  
Angela S. Alberga ◽  
Denis Prud’homme ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Composition ◽  
Body Weight ◽  
Muscle Mass ◽  
Energy Intake ◽  
Skeletal Muscle Mass ◽  
Fat Free Mass ◽  
Cross Sectional ◽  
Percentage Body Fat ◽  
Obese Adolescents

There has been renewed interest in examining the relationship between specific components of energy expenditure and the overall influence on energy intake (EI). The purpose of this cross-sectional analysis was to determine the strongest metabolic and anthropometric predictors of EI. It was hypothesized that resting metabolic rate (RMR) and skeletal muscle mass would be the strongest predictors of EI in a sample of overweight and obese adolescents. 304 post-pubertal adolescents (91 boys, 213 girls) aged 16.1 (±1.4) years with body mass index at or above the 95th percentile for age and sex OR at or above the 85th percentile plus an additional diabetes risk factor were measured for body weight, RMR (kcal/day) by indirect calorimetry, body composition by magnetic resonance imaging (fat free mass (FFM), skeletal muscle mass, fat mass (FM), and percentage body fat), and EI (kcal/day) using 3 day food records. Body weight, RMR, FFM, skeletal muscle mass, and FM were all significantly correlated with EI (p < 0.005). After adjusting the model for age, sex, height, and physical activity, only FFM (β = 21.9, p = 0.007) and skeletal muscle mass (β = 25.8, p = 0.02) remained as significant predictors of EI. FFM and skeletal muscle mass also predicted dietary protein and fat intake (p < 0.05), but not carbohydrate intake. In conclusion, with skeletal muscle mass being the best predictor of EI, our results support the hypothesis that the magnitude of the body’s lean tissue is related to absolute levels of EI in a sample of inactive adolescents with obesity.

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