scholarly journals Short-Term Creatine Loading Improves Total Work and Repetitions to Failure but Not Load–Velocity Characteristics in Strength-Trained Men

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 826
Author(s):  
Joshua F. Feuerbacher ◽  
Valerian von Schöning ◽  
Judith Melcher ◽  
Hannah L. Notbohm ◽  
Nils Freitag ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Creatine Supplementation ◽  
Effect Sizes ◽  
Total Work ◽  
Maximal Strength ◽  
Short Term ◽  
Placebo Condition ◽  
Main Effect ◽  
Deep Squat ◽  
Repetitions To Failure

This study assessed the effects of a 7-day creatine (CRE) supplementation on the load–velocity profile and repeated sub-maximal bouts in the deep squat using mean propulsive velocity (MPV) and mean propulsive power (MPP). Eleven strength-trained men (31.4 ± 5.4 years) supplemented 0.3 g·kg−1·d−1 CRE or a placebo (PLA, maltodextrin) for seven days in a randomized order, separated by a 30-day washout period. Prior to and after the supplementation, the subjects performed an incremental maximal strength (1RM) test, as well as 3 × 10 repetitions and a repetitions-to-failure test (RFT), all at 70% 1RM. Maximal strength remained statistically unaltered in CRE (p = 0.107) and PLA (p = 0.568). No statistical main effect for time (p = 0.780) or interaction (p = 0.737) was observed for the load–velocity profile. The number of repetitions during RFT remained statistically unaltered in both conditions (CRE: +16.8 ± 32.8%, p = 0.112; PLA: +8.2 ± 47.2%, p = 0.370), but the effect size was larger in creatine compared to placebo (g = 0.51 vs. g = 0.01). The total work during RFT increased following creatine supplementation (+23.1 ± 35.9%, p = 0.043, g = 0.70) but remained statistically unaltered in the placebo condition (+15.0 ± 60.8%, p = 0.801, g = 0.08; between conditions: p = 0.410, g = 0.25). We showed that CRE loading over seven days did not affect load–velocity characteristics but may have increased total work and power output during submaximal deep squat protocols, as was indicated by moderate effect sizes.

scholarly journals Discontinuities in a Transverse Velocity Profile of a Valley Glacier Measured by Photogrammetry

1989 ◽  
Vol 12 ◽  
pp. 89-91 ◽  
Author(s):  
W. Kick
Keyword(s):  
Velocity Profile ◽  
Single Unit ◽  
Transverse Velocity ◽  
Short Term ◽  
En Bloc ◽  
Block Motion ◽  
Valley Glacier ◽  
Unit Block ◽  
Time Periods ◽  
Shear Planes

The surface movement of part of a Nanga Parbat (Himalaya) glacier immediately below an ice fall has been investigated by terrestrial stereophotogrammetry. This method provides an opportunity of measuring many more points than by using other procedures. The shape of the transverse velocity profile indicated normal stream-like flow and not “blockschollen movement”, as might have been expected, because of its high velocity (45 cm/d). But, one feature of the ice fall above had been carried down-glacier to the location of the profile; namely, several discontinuities along the velocity diagram. The ice fall had transmitted a small part of its splitting into seracs to the flatter area below, but not its blockschollen movement. There seems to be a contradiction in that on one side there are discontinuities, i.e. the glacier is torn up into blocks by shear planes, but on the other side the glacier moves en bloc. In fact, a short-term investigation over hours or just a few days discloses cracks but, after time periods of a week or more, these irregularities compensate for one another so that they merge into a single unit block motion.

scholarly journals Acute and Short-Term Effects of Dry Needling in Patients with Chronic Nonspecific Low Back Pain and Hamstring Tightness: A Pilot Study

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Mahnaz Bazzaz-Yamchi ◽  
Soofia Naghdi ◽  
Amin Nakhostin-Ansari ◽  
Monavar Hadizadeh ◽  
Noureddin Nakhostin Ansari ◽  
...  
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Pilot Study ◽  
Study Design ◽  
Effect Sizes ◽  
Medium Effect ◽  
Low Back ◽  
Dry Needling ◽  
Short Term ◽  
Short Term Effects

Background. Chronic nonspecific low back pain (LBP) is one of the common health issues. Hamstring tightness contributes to the development of LBP. This study aimed to investigate the acute and short-term effects of deep dry needling (DN) in patients with chronic nonspecific LBP and hamstring muscle tightness. Methods. A single-group pretest-posttest clinical study design was followed. The outcome measures were the visual analog scale (VAS), passive knee extension (PKE) test, finger-floor distance (FFD) test, and functional rating index (FRI). Patients underwent one session of deep DN of three points on both hamstring muscles, each point for one minute. Patients were assessed before (T0), immediately after (T1), and one week after DN (T2). The FRI was assessed at T0 and T2. Results. Ten women with a mean age of 21.1 years (SD = 1.6) participated in the study. Significant large effect sizes in VAS pain reduction (d = 1.25) and PKE hamstring tightness were obtained (hamstring: right, d = 0.82; left, d = 0.88) at T2. Medium effect sizes were obtained for FFD (d = 0.45) and FRI (d = 0.72) at T2. Conclusion. A single session of deep DN improved pain and function and increased hamstring flexibility. This pilot study supports the use of DN in patients with LBP and hamstring tightness; however, future research with a rigorous study design of randomized controlled trial is required to confirm the findings. This trial is registered with IRCT20180511039612N1.

scholarly journals Preserving Isometric Maximal Strength Using Short-Term Training Cessation

2021 ◽  
Vol 53 (8S) ◽  
pp. 40-41
Author(s):  
S. Kyle Travis ◽  
Kevin A. Zwetsloot ◽  
Iñigo Mujika ◽  
Jeremy A. Gentles ◽  
Michael H. Stone ◽  
...  
Keyword(s):  
Maximal Strength ◽  
Short Term

The Relationship between Goal Proximity and Specificity in Bowling: A Field Experiment

1990 ◽  
Vol 4 (2) ◽  
pp. 145-154 ◽  
Author(s):  
Steven H. Frierman ◽  
Robert S. Weinberg ◽  
Allen Jackson
Keyword(s):  
Goal Setting ◽  
Repeated Measures ◽  
Questionnaire Data ◽  
Short Term ◽  
Level Of Confidence ◽  
Goal Condition ◽  
Main Effect ◽  
The Relationship ◽  
Better Than

The purpose of this investigation was twofold: to determine if individuals who were assigned specific, difficult goals perform better than those assigned “do your best” goals, and to examine the importance of goal proximity (longterm vs. short-term) on bowling performance. Subjects were 72 students enrolled in two beginning bowling courses at a 4-year university. They were matched according to baseline bowling averages and then randomly assigned to one of four goal-setting conditions. A 4 × 5 (Goal Condition × Trials) ANOVA with repeated measures on the last factor revealed a significant goal condition main effect, with the long-term goal group improving more than the do-your-best group. No other performance comparisons reached significance. Questionnaire data revealed that subjects in all three numerical goal conditions rated their level of confidence significantly higher than the do-your-best goal group in Week 1, but the long-term goal group displayed a significantly higher level of confidence than the other three goal groups in Week 4. All other questions indicated that all groups tried hard and were committed to and accepted their goals.

Distrust of Employers, Collectivism, and Union Efficacy

2013 ◽  
Vol 4 (4) ◽  
pp. 13-26 ◽  
Author(s):  
Jack Fiorito ◽  
Daniel G. Gallagher
Keyword(s):  
Knowledge Work ◽  
Effect Sizes ◽  
Medium Effect ◽  
Future Research ◽  
Discussion Section ◽  
Worker Attitudes ◽  
Moderator Effects ◽  
Main Effect ◽  
Limited Support ◽  
Survey Results

This study examines relations between indicators of knowledge work and worker attitudes toward employers, collective action, and union efficacy. Previous writing on these relations are used to develop hypotheses. Data are drawn from the 2009 Young Workers Survey. Results fail to show any statistically significant main effect relations between knowledge work indicators and the worker attitudes examined, despite a sample size sufficient to detect at least medium effect sizes. Further, there is very limited support for moderator effects. A discussion section discusses limitations, implications, and issues for future research.

Applying the Critical Power Model to a Full-Body Resistance-Training Movement

2019 ◽  
Vol 14 (10) ◽  
pp. 1364-1370 ◽  
Author(s):  
Taylor K. Dinyer ◽  
M. Travis Byrd ◽  
Ashley N. Vesotsky ◽  
Pasquale J. Succi ◽  
Haley C. Bergstrom
Keyword(s):  
Linear Regression ◽  
Critical Power ◽  
Total Work ◽  
Simple Linear Regression ◽  
Paired Samples ◽  
Body Resistance ◽  
Distance Relationship ◽  
Repetitions To Failure ◽  
The Mathematical Model ◽  
Critical Resistance

Purpose: To determine if the mathematical model used to derive critical power could be used to identify the critical resistance (CR) for the deadlift; compare predicted and actual repetitions to failure at 50%, 60%, 70%, and 80% 1-repetition maximum (1RM); and compare the CR with the estimated sustainable resistance for 30 repetitions (ESR30). Methods: Twelve subjects completed 1RM testing for the deadlift followed by 4 visits to determine the number of repetitions to failure at 50%, 60%, 70%, and 80% 1RM. The CR was calculated as the slope of the line of the total work completed (repetitions × weight [in kilograms] × distance [in meters]) vs the total distance (in meters) the barbell traveled. The actual and predicted repetitions to failure were determined from the CR model and compared using paired-samples t tests and simple linear regression. The ESR30 was determined from the power-curve analysis and compared with the CR using paired-samples t tests and simple linear regression. Results: The weight and repetitions completed at CR were 56 (11) kg and 49 (14) repetitions. The actual repetitions to failure were less than predicted at 50% 1RM (P < .001) and 80% 1RM (P < .001) and greater at 60% 1RM (P = .004), but there was no difference at 70% 1RM (P = .084). The ESR30 (75 [14] kg) was greater (P < .001) than the CR. Conclusions: The total work-vs-distance relationship can be used to identify the CR for the deadlift, which reflected a sustainable resistance that may be useful in the design of resistance-based exercise programs.

scholarly journals Creatine Use in Sports

2017 ◽  
Vol 10 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Jessica Butts ◽  
Bret Jacobs ◽  
Matthew Silvis
Keyword(s):  
Dietary Supplement ◽  
National Collegiate Athletic Association ◽  
Creatine Supplementation ◽  
Sports Performance ◽  
Short Term ◽  
Level Of Evidence ◽  
Improved Performance ◽  
Google Search ◽  
Long Term Studies

Context: The use of creatine as a dietary supplement has become increasingly popular over the past several decades. Despite the popularity of creatine, questions remain with regard to dosing, effects on sports performance, and safety. Evidence Acquisition: PubMed was searched for articles published between 1980 and January 2017 using the terms creatine, creatine supplementation, sports performance, and dietary supplements. An additional Google search was performed to capture National Collegiate Athletic Association–specific creatine usage data and US dietary supplement and creatine sales. Study Design: Clinical review. Level of Evidence: Level 4. Results: Short-term use of creatine is considered safe and without significant adverse effects, although caution should be advised as the number of long-term studies is limited. Suggested dosing is variable, with many different regimens showing benefits. The safety of creatine supplementation has not been studied in children and adolescents. Currently, the scientific literature best supports creatine supplementation for increased performance in short-duration, maximal-intensity resistance training. Conclusion: While creatine appears to be safe and effective for particular settings, whether creatine supplementation leads to improved performance on the field of play remains unknown.

Factors Contributing to Intra-Individual Variation of Serum Constituents: 5. Short-Term Day-to-Day and Within-Hour Variation of Serum Constituents in Healthy Subjects

1974 ◽  
Vol 20 (12) ◽  
pp. 1520-1527 ◽  
Author(s):  
Per Winkel ◽  
Bernard E Statland ◽  
Henning Bokelund
Keyword(s):  
Total Lipids ◽  
Short Term ◽  
Serum Samples ◽  
Interaction Terms ◽  
Anova Model ◽  
First Case ◽  
Main Effect ◽  
Relationship Of ◽  
The Relationship ◽  
Analytical Variation

Abstract We evaluated the variations in some serum constituents in a group of healthy young men for two selected time intervals: short-term day-to-day changes and within-hour changes. In the first case, we used a two-way ANOVA model to compute the main-day effect and the subject-day interaction terms, which were combined to yield the total day-to-day variation. A main-day effect was seen to be statistically significant only for acid phosphatase, while all of the 18 serum constituents except for sodium, calcium, and albumin demonstrated a statistically significant subject-day interaction. For the within-hour biologic variation, a three-way ANOVA model was used to analyze results of duplicate serum samples drawn at 1100 h and 1130 h on two different days. Although a significant main effect of hour was found only for total lipids and alkaline phosphatase, pooling the main effect of hour, subject-hour interaction, and subject-day-hour interaction terms resulted in a chemically significant variation for potassium, total protein, albumin, iron, total lipids, cholesterol, and bilirubin. The relationship of these biological fluctuations is compared to the expected analytical variation in all cases.

Effect of short-term creatine supplementation on renal responses in men

1997 ◽  
Vol 76 (6) ◽  
pp. 566-567 ◽  
Author(s):  
J. R. Poortmans ◽  
H. Auquier ◽  
V. Renaut ◽  
A. Durussel ◽  
M. Saugy ◽  
...  
Keyword(s):  
Creatine Supplementation ◽  
Short Term ◽  
Renal Responses

Opposite actions of caffeine and creatine on muscle relaxation time in humans

2002 ◽  
Vol 92 (2) ◽  
pp. 513-518 ◽  
Author(s):  
P. Hespel ◽  
B. Op ‘t Eijnde ◽  
M. Van Leemputte
Keyword(s):  
Relaxation Time ◽  
Exercise Test ◽  
Muscle Relaxation ◽  
Creatine Supplementation ◽  
Caffeine Intake ◽  
Short Term ◽  
Experimental Conditions ◽  
Double Blind ◽  
Musculus Quadriceps ◽  
Intermittent Contractions

The effect of creatine and caffeine supplementation on muscle torque generation and relaxation was investigated in healthy male volunteers. Maximal torque (Tmax), contraction time (CT) from 0.25 to 0.75 of Tmax, and relaxation time (RT) from 0.75 to 0.25 of Tmax were measured during an exercise test consisting of 30 intermittent contractions of musculus quadriceps (2 s stimulation, 2 s rest) that were induced by electrical stimulation. According to a double-blind randomized crossover design, subjects ( n = 10) performed the exercise test before (pretest) and after (posttest) creatine supplementation (Cr, 4 × 5 g/day, 4 days), short-term caffeine intake (Caf, 5 mg · kg−1 · day−1, 3 days), creatine supplementation + short-term caffeine intake (Cr+Caf), acute caffeine intake (ACaf, 5 mg/kg) or placebo. Compared with placebo, Cr shortened RT by ∼5% ( P < 0.05). Conversely, Caf increased RT (+∼10%, P < 0.05), in particular as RT increased because of fatigue. RT was not significantly changed by either Cr+Caf or ACaf. Tmax and CT were similar during all experimental conditions. Initial Tmax was ∼20% of voluntary maximal isometric contraction force, which was not different between treatments. It is concluded that Caf intake (3 days) prolongs muscle RT and by this action overrides the shortening of RT due to creatine supplementation.

Sign in / Sign up

Export Citation Format

Share Document