Effects of Creatine Loading on Electromyographic Fatigue Threshold in Cycle Ergometry in College-Age Men

2008 ◽  
Vol 18 (2) ◽  
pp. 142-151 ◽  
Author(s):  
Ashley A. Walter ◽  
Abbie E. Smith ◽  
Trent J. Herda ◽  
Eric D. Ryan ◽  
Jordan R. Moon ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Cycle Ergometer ◽  
Fatigue Threshold ◽  
Double Blind Study ◽  
Double Blind ◽  
College Age ◽  
Cycle Ergometer Test ◽  
Before And After ◽  
The Right ◽  
Ergometer Test

The purpose of this study was to examine the effects of 5 d of creatine (Cr) loading on the electromyographic fatigue threshold (EMG FT) in college-age men. Sixteen men (age 22.4 ± 2.6 yr, height 177.4 ± 6.8 cm, weight 79.5 ± 10.6 kg; M ± SD) participated in this double-blind study and were randomly placed into either placebo (Pl; 10 g of flavored fructose powder per packet; n = 8) or Cr (5 g dicreatine citrate plus 10 g of flavored fructose powder per packet; n = 8) loading groups. Each participant ingested 1 packet 4 times/d, totaling 20 g/d for 5 days (loading). Before and after loading, each participant performed a discontinuous cycle-ergometer test to determine his EMG FT, using bipolar surface electrodes placed on the vastus lateralis of the right thigh. Four 60-s work bouts (ranging from 200 to 400 W) were completed. Adequate rest was given between bouts to allow for the participants’ heart rate (HR) to drop within 10 beats of their resting HR. The EMG amplitude was averaged over 5-s intervals for each 60-s work bout. Resulting slopes from each successive work bout were used to calculate EMG FT. A 2-way ANOVA, Group (Cr vs. Pl) EETime (pre vs. post), resulted in a nonsignificant (p > .05) interaction for supplement and time. In addition, a significant increase (p = .009) in weight was observed in the Cr group. These data suggest that there was a minimal influence of Cr loading on EMG FT for the participants in this study.

Effect of beta-blockade on the drift in O2 consumption during prolonged exercise

1988 ◽  
Vol 64 (2) ◽  
pp. 753-758 ◽  
Author(s):  
J. K. Kalis ◽  
B. J. Freund ◽  
M. J. Joyner ◽  
S. M. Jilka ◽  
J. Nittolo ◽  
...  
Keyword(s):  
Heart Rate ◽  
Minute Ventilation ◽  
Cycle Ergometer ◽  
Beta Blockade ◽  
Adrenergic Blockade ◽  
Maximal Heart Rate ◽  
O2 Consumption ◽  
Double Blind ◽  
Cycle Ergometer Test ◽  
Ergometer Test

The effect of beta-adrenergic blockade on the drift in O2 consumption (VO2 drift) typically observed during prolonged constant-rate exercise was studied in 14 healthy males in moderate heat at 40% of maximal O2 consumption (VO2max). After an initial maximum cycle ergometer test to determine the subjects' control VO2max, subjects were administered each of three medications: placebo, atenolol (100 mg once daily), and propranolol (80 mg twice daily), in a randomized double-blind fashion. Each medication period was 5 days in length and was followed by a 4-day washout period. On the 3rd day of each medication period, subjects performed a maximal cycle ergometer test. On the final day of each medication period, subjects exercised at 40% of their control VO2max for 90 min on a cycle ergometer in a warm (31.7 +/- 0.3 degrees C) moderately humid (44.7 +/- 4.7%) environment. beta-Blockade caused significant (P less than 0.05) reductions in VO2max, maximal minute ventilation (VEmax), maximal heart rate (HRmax), and maximal exercise time. Significantly greater decreases in VO2max, VEmax, and HRmax were associated with the propranolol compared with the atenolol treatment. During the 90-min submaximal rides, beta-blockade significantly reduced heart rate. Substantially lower values for O2 consumption (VO2) and minute ventilation (VE) were observed with propranolol compared with atenolol or placebo. Furthermore, VO2 drift and HR drift were observed under atenolol and placebo conditions but not with propranolol. Respiratory exchange ratio decreased significantly over time during the placebo and atenolol trials but did not change during the propranolol trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Validation of the 12-Minute Cycle Ergometer Test Using a Higher Resistance Setting

1993 ◽  
Vol 2 (4) ◽  
pp. 268-273
Author(s):  
Paul M. Vanderburgh ◽  
Ronald E. DeMeersman
Keyword(s):  
Body Weight ◽  
Cycle Ergometer ◽  
Total Work ◽  
College Age ◽  
Cycle Ergometer Test ◽  
Prediction Test ◽  
Ergometer Test ◽  
Work Done

The 12-Minute Stationary Cycle Ergometer Test (12MCET) has been developed and validated as an accurate VO2peak prediction test particularly for the injured (7). Prediction is based on body weight and total work done in 12 min at a resistance setting of 2.5 kp (men) and 2.0 kp (women) on the Monark cycle ergometer. In the development of the 12MCET a small number of subjects stated a preference for a higher resistance setting than 2.5 kp. The purpose of this study was to validate the use of the 12MCET with a resistance setting of 3.0 kp for a sample of 30 college-age men. When applied to the 12MCET, use of the 3.0 kp resistance setting overpredicted actual VO2peak by a mean of 175 ml • min−1(p= .02). We concluded that the use of a 3.0 kp resistance setting for the 12MCET is inappropriate and that any resistance setting other than that prescribed should not be used without proper validation.

The 12-Minute Stationary Cycle Ergometer Test: An Efficacious VO2peak Prediction Test for the Injured

1993 ◽  
Vol 2 (3) ◽  
pp. 189-195 ◽  
Author(s):  
Paul M. Vanderburgh
Keyword(s):  
High Intensity ◽  
Cycle Ergometer ◽  
Open Circuit ◽  
Physically Active ◽  
Men And Women ◽  
College Age ◽  
Cycle Ergometer Test ◽  
Prediction Test ◽  
Gender Based ◽  
Ergometer Test

Previously there existed no efficacious maximal effort, VO2peak prediction test for subjects who, because of injury, can exercise at high intensity only on a device such as a cycle ergometer. This study's purpose was to develop and validate such a test, a 12-Minute Stationary Cycle Ergometer Test (12MSCET), for college-age physically active men and women. For 60 college-age men and women, and a gender-based resistance setting, the total work done on the 12MSCET and body weight were found to be highly predictive of VO2peak, measured via open circuit spirometry. Furthermore, the torques required for such a test are, for this sample, approximately 50% of those required in other predictive protocols. To date, the 12MSCET has been used for VO2peak assessment of over 300 military cadets who, because of injury, found cycling their only efficacious high-intensity aerobic modality.

AMP kinase expression and activity in human skeletal muscle: effects of immobilization, retraining, and creatine supplementation

2005 ◽  
Vol 98 (4) ◽  
pp. 1228-1233 ◽  
Author(s):  
Bert O. Eijnde ◽  
Wim Derave ◽  
Jørgen F. P. Wojtaszewski ◽  
Erik A. Richter ◽  
Peter Hespel
Keyword(s):  
Protein Expression ◽  
Vastus Lateralis ◽  
Creatine Supplementation ◽  
Knee Extensor ◽  
Double Blind ◽  
Α Subunit ◽  
Beneficial Effects ◽  
Before And After ◽  
Subunit Expression ◽  
The Right

The effects of leg immobilization and retraining in combination with oral creatine intake on muscle AMP-activated protein kinase (AMPK) protein expression and phosphorylation status were investigated. A double-blind trial was performed in young healthy volunteers ( n = 22). A cast immobilized the right leg for 2 wk, whereafter the knee-extensor muscles of that leg were retrained for 6 wk. Half of the subjects received creatine monohydrate throughout the study (Cr; from 15 g down to 2.5 g daily), and the others ingested placebo (P; maltodextrin). Before and after immobilization and retraining, needle biopsies were taken from the right and left vastus lateralis muscles. In the right leg of P and Cr, immobilization did not affect AMPK α1-, α2-, and β2-subunit expression or AMPK α-subunit phosphorylation status. However, irrespective of the treatment received, retraining increased the degree of α-subunit phosphorylation by ∼25% ( P < 0.05) and increased AMPK α1-subunit expression ( P < 0.05) in both groups. From the start to the end of the study, AMPK subunit protein expression and α-subunit phosphorylation status were unchanged in the contralateral control leg. It is concluded that immobilization-induced muscle inactivity for 2 wk does not alter AMPK α1-, α2-, and β2-subunit expression or α-AMPK phosphorylation status. Furthermore, the present observations indicate that AMPK probably is not implicated in the previously reported beneficial effects of oral creatine supplementation on muscle during immobilization and rehabilitative weight training.

Iron supplementation improves endurance after training in iron-depleted, nonanemic women

2000 ◽  
Vol 88 (3) ◽  
pp. 1103-1111 ◽  
Author(s):  
Pamela S. Hinton ◽  
Christina Giordano ◽  
Thomas Brownlie ◽  
Jere D. Haas
Keyword(s):  
Aerobic Exercise ◽  
Serum Ferritin ◽  
Iron Supplementation ◽  
Iron Status ◽  
Time Trial ◽  
Cycle Ergometer ◽  
Group Differences ◽  
Double Blind ◽  
Cycle Ergometer Test ◽  
Ergometer Test

Our objective was to investigate the effects of iron depletion on adaptation to aerobic exercise, assessed by time to complete a 15-km cycle ergometer test. Forty-two iron-depleted (serum ferritin <16 μg/l), nonanemic (Hb >12 g/dl) women (18–33 yr old) received 100 mg of ferrous sulfate (S) or placebo (P) per day for 6 wk in a randomized, double-blind trial. Subjects trained for 30 min/day, 5 days/wk at 75–85% of maximum heart rate for the final 4 wk of the study. There were no group differences in baseline iron status or in 15-km time. Iron supplementation increased serum ferritin and decreased transferrin receptors in the S compared with the P group. The S and P groups decreased 15-km time and respiratory exchange ratio and increased work rate during the 15-km time trial after training. The decrease in 15-km time was greater in the S than in the P group ( P = 0.04) and could be partially attributed to increases in serum ferritin and Hb. These results indicate that iron deficiency without anemia impairs favorable adaptation to aerobic exercise.

Evaluation of Nasal Volume by Acoustic Rhinometry before and after Physical Exercise

2006 ◽  
Vol 20 (3) ◽  
pp. 269-273 ◽  
Author(s):  
Marconi T. Fonseca ◽  
Richard L. Voegels ◽  
Kelerson M. C. Pinto
Keyword(s):  
Physical Exercise ◽  
Cycle Ergometer ◽  
Acoustic Rhinometry ◽  
Load Test ◽  
Cycle Ergometer Test ◽  
Maximal Load ◽  
Significant Difference ◽  
Before And After ◽  
Physical Tests ◽  
Ergometer Test

Background The nasal structures generate airflow resistance that can reach ∼50% of the total respiratory resistance. There are a series of factors that can alter the volume of these structures, among them physical exercise. The objective of this study was to determine the degree of changes in nasal volume at different levels of physical exercise, evaluating the influence of exercise intensity and duration, as well as the duration of the effect of exercise on the nasal mucosa. Methods Nineteen individuals were submitted to three distinct physical tests on a cycle ergometer: test 1, exercising for 5 minutes on a cycle ergometer at 50% the maximal load; test 2, exercising for 10 minutes on a cycle ergometer at 50% the maximal load; and test 3, exercising for 5 minutes on a cycle ergometer at 75% the maximal load. In each test, nasal volume was measured by acoustic rhinometry immediately after the end of exercise and 10 and 20 minutes thereafter. Results The rhinometry results showed a significant increase (p < 0.001) in nasal volume after physical exercise for all tests performed. At 20 minutes, nasal volume had returned close to resting levels in all three tests. Comparison of the degree of improvement of nasal volume between the three physical tests showed a significant difference (p < 0.05) between T1 and T2 (T2 presented gain of 8.3% more in nasal volume than T1). Test 3 showed no significant difference (p > 0.05) compared with the other two tests, with 5.8% higher gain in nasal volume observed compared with T1, while the increase was 2.5% lower than in T2. Conclusion Physical exercise in general causes a significant increase in nasal volume, with the duration of exercise exerting a greater effect on the degree of improvement than intensity.

The 10-min Cycle Ergometer Test

1998 ◽  
Vol 12 (1) ◽  
pp. 12-17
Author(s):  
Paul M. Vanderburgh ◽  
Greg Daniels ◽  
Todd A. Crowder ◽  
Tony Lachowetz ◽  
Robb Elliott
Keyword(s):  
Cycle Ergometer ◽  
Cycle Ergometer Test ◽  
Ergometer Test

A Clinical Method for Estimation of VO2max Using Seismocardiography

2020 ◽  
Vol 41 (10) ◽  
pp. 661-668
Author(s):  
Kasper Sørensen ◽  
Mathias Krogh Poulsen ◽  
Dan Stieper Karbing ◽  
Peter Søgaard ◽  
Johannes Jan Struijk ◽  
...  
Keyword(s):  
Prediction Model ◽  
Cardiorespiratory Fitness ◽  
Demographic Data ◽  
Cycle Ergometer ◽  
Accurate Estimation ◽  
Clinical Method ◽  
Cycle Ergometer Test ◽  
Aortic Valve Closure ◽  
Proposed Model ◽  
Ergometer Test

AbstractThe purpose of this study was to investigate the correlation between the seismocardiogram and cardiorespiratory fitness. Cardiorespiratory fitness can be estimated as VO2max using non-exercise algorithms, but the results can be inaccurate. Healthy subjects were recruited for this study. Seismocardiogram and electrocardiogram were recorded at rest. VO2max was measured during a maximal effort cycle ergometer test. Amplitudes and timing intervals were extracted from the seismocardiogram and used in combination with demographic data in a non-exercise prediction model for VO2max. 26 subjects were included, 17 females. Mean age: 38.3±9.1 years. The amplitude following the aortic valve closure derived from the seismocardiogram had a significant correlation of 0.80 (p<0.001) to VO2max. This feature combined with age, sex and BMI in the prediction model, yields a correlation to VO2max of 0.90 (p<0.001, 95% CI: 0.83–0.94) and a standard error of the estimate of 3.21 mL·kg−1·min−1 . The seismocardiogram carries information about the cardiorespiratory fitness. When comparing to other non-exercise models the proposed model performs better, even after cross validation. The model is limited when tracking changes in VO2max. The method could be used in the clinic for a more accurate estimation of VO2max compared to current non-exercise methods.

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