The Relationship Between Freely Chosen Cadence and Optimal Cadence in Cycling

2012 ◽  
Vol 7 (4) ◽  
pp. 375-381 ◽  
Author(s):  
Umberto Emanuele ◽  
Tamara Horn ◽  
Jachen Denoth
Keyword(s):  
Power Output ◽  
Body Position ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peripheral Fatigue ◽  
External Power ◽  
The Relationship ◽  
Optimal Cadence ◽  
Cycling Condition ◽  
Constant Power Output

Purpose:The main aim of this study was to compare the freely chosen cadence (FCC) and the cadence at which the blood lactate concentration at constant power output is minimized (optimal cadence [Copt]). The second aim was to examine the effect of a concomitant change of road incline and body position on FCC, the maximal external power output (Pmax), and the corresponding Copt.Methods:FCC, Copt, and Pmax were analyzed under 2 conditions: cycling on level ground in a dropped position (LGDP) and cycling uphill in an upright position (UHUP). Seven experienced cyclists participated in this study. They cycled on a treadmill to test the 2 main hypotheses: Experienced cyclists would choose an adequate cadence close to Copt independent of the cycling condition, and FCC and Copt would be lower and Pmax higher for UHUP than with LGDP.Results:Most but not all experienced cyclists chose an adequate cadence close to Copt. Independent of the cycling condition, FCC and Copt were not statistically different. FCC (82.1 ± 11.1 and 89.3 ± 10.6 rpm, respectively) and Copt (81.5 ± 9.8 and 87.7 ± 10.9 rpm, respectively) were significantly lower and Pmax was significantly higher (2.0 ± 2.1%) for UHUP than for LGDP.Conclusion:Most experienced cyclists choose a cadence near Copt to minimize peripheral fatigue at a given power output independent of the cycling condition. Furthermore, it is advantageous to use a lower cadence and a more upright body position during uphill cycling.

Blood Lactate Concentration and Clearance in Elite Swimmers During Competition

2011 ◽  
Vol 6 (1) ◽  
pp. 106-117 ◽  
Author(s):  
Jason D. Vescovi ◽  
Olesya Falenchuk ◽  
Greg D. Wells
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Active Recovery ◽  
Competitive Swimming ◽  
Elite Swimmers ◽  
Lactate Removal ◽  
The Relationship ◽  
Competitive Swimmers ◽  
Effect Of Age

Purpose:Blood lactate concentration, [BLa], after swimming events might be influenced by demographic features and characteristics of the swim race, whereas active recovery enhances blood lactate removal. Our aims were to (1) examine how sex, age, race distance, and swim stroke influenced [BLa] after competitive swimming events and (2) develop a practical model based on recovery swim distance to optimize blood lactate removal.Methods:We retrospectively analyzed postrace [BLa] from 100 swimmers who competed in the finals at the Canadian Swim Championships. [BLa] was also assessed repeatedly during the active recovery. Generalized estimating equations were used to evaluate the relationship between postrace [BLa] with independent variables.Results:Postrace [BLa] was highest following 100–200 m events and lowest after 50 and 1500 m races. A sex effect for postrace [BLa] was observed only for freestyle events. There was a negligible effect of age on postrace [BLa]. A model was developed to estimate an expected change in [BLa] during active recovery (male = 0; female = 1): [BLa] change after active recovery = –3.374 + (1.162 × sex) + (0.789 × postrace [BLa]) + (0.003 × active recovery distance).Conclusions:These findings indicate that swimmers competing at an elite standard display similar postrace [BLa] and that there is little effect of age on postrace [BLa] in competitive swimmers aged 14 to 29 y.

Physiological and metabolic responses as function of the mechanical load in resistance exercise

2014 ◽  
Vol 39 (3) ◽  
pp. 345-350 ◽  
Author(s):  
Sebastian Buitrago ◽  
Nicolas Wirtz ◽  
Ulrich Flenker ◽  
Heinz Kleinöder
Keyword(s):  
Resistance Exercise ◽  
Mechanical Load ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Maximum Velocity ◽  
Linear Increase ◽  
Detectable Effect ◽  
Turnover Rates ◽  
Post Exercise ◽  
The Relationship

The present study aimed to investigate the relationship between the mechanical load during resistance exercise and the elicited physiological responses. Ten resistance-trained healthy male subjects performed 1 set of resistance exercise each at 55%, 70%, and 85% of 1 repetition maximum for as many repetitions as possible and in 4 training modes: 4-1-4-1 (4 s concentric, 1 s isometric, 4 s eccentric, and 1 s isometric successive actions), 2-1-2-1, 1-1-1-1, and explosive (maximum velocity concentric). Mean concentric power and total concentric work were determined. Oxygen uptake (V̇O2) was measured during exercise and for 30 min post exercise. Total volume of consumed oxygen (O2 consumed) and excess post-exercise oxygen consumption (EPOC) were calculated. Maximum blood lactate concentration (LAmax) was also determined. V̇O2 exhibited a linear dependency on mean concentric power. Mean concentric power did not have a detectable effect on EPOC and LAmax. An augmentation of total concentric work resulted in significant linear increase of O2 consumed and EPOC. Total concentric work caused a significant increase in LAmax. In general, a higher mechanical load induced a larger physiological response. An increase in mean concentric power elicited higher aerobic energy turnover rates. However, a higher extent of total concentric work augments total energy cost covered by oxidative and (or) glycolytic pathways.

scholarly journals Detection of the Lactate Threshold in Runners: What is the Ideal Speed to Start an Incremental Test?

2015 ◽  
Vol 45 (1) ◽  
pp. 217-224 ◽  
Author(s):  
José Luiz Dantas ◽  
Christian Doria
Keyword(s):  
Blood Lactate ◽  
Lactate Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Endurance Athletes ◽  
Incremental Test ◽  
Average Speed ◽  
Third Stage ◽  
The Relationship ◽  
The Ideal

Abstract Incremental tests on a treadmill are used to evaluate endurance athletes; however, no criterion exists to determine the intensity at which to start the test, potentially causing the loss of the first lactate threshold. This study aimed to determine the ideal speed for runners to start incremental treadmill tests. The study consisted of 94 runners who self-reported the average speed from their last competitive race (10-42.195 km) and performed an incremental test on a treadmill. The speeds used during the first three test stages were normalised in percentages of average competition speed and blood lactate concentration was analysed at the end of each stage. The relationship between speed in each stage and blood lactate concentration was analysed. In the first stage, at an intensity corresponding to 70% of the reported average race speed, only one volunteer had blood lactate concentration equal to 2 mmol·L-1, and in the third stage (90% of the average race speed) the majority of the volunteers had blood lactate concentration ≥2 mmol·L-1. Our results demonstrated that 70% of the average speed from the subject’s last competitive race - from 10 to 42.195 km - was the best option for obtaining blood lactate concentration <2 mmol·L-1 in the first stage, however, 80% of the average speed in marathons may be a possibility. Evaluators can use 70% of the average speed in competitive races as a strategy to ensure that the aerobic threshold intensity is not achieved during the first stage of incremental treadmill tests.

scholarly journals Complex Interplay Between Determinants of Pacing and Performance During 20-km Cycle Time Trials

2012 ◽  
Vol 7 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Andrew Renfree ◽  
Julia West ◽  
Mark Corbett ◽  
Clare Rhoden ◽  
Alan St Clair Gibson
Keyword(s):  
Negative Affect ◽  
Blood Lactate ◽  
Power Output ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Rating Of Perceived Exertion ◽  
Physiological Status ◽  
Pacing Strategy ◽  
And Performance

Purpose:This study examined the determinants of pacing strategy and performance during self-paced maximal exercise.Methods:Eight well-trained cyclists completed two 20-km time trials. Power output, rating of perceived exertion (RPE), positive and negative affect, and iEMG activity of the active musculature were recorded every 0.5 km, confidence in achieving preexercise goals was assessed every 5 km, and blood lactate and pH were measured postexercise. Differences in all parameters were assessed between fastest (FAST) and slowest (SLOW) trials performed.Results:Mean power output was significantly higher during the initial 90% of FAST, but not the final 10%, and blood lactate concentration was significantly higher and pH significantly lower following FAST. Mean iEMG activity was significantly higher throughout SLOW. Rating of perceived exertion was similar throughout both trials, but participants had significantly more positive affect and less negative affect throughout FAST. Participants grew less confident in their ability to achieve their goals throughout SLOW.Conclusions:The results suggest that affect may be the primary psychological regulator of pacing strategy and that higher levels of positivity and lower levels of negativity may have been associated with a more aggressive strategy during FAST. Although the exact mechanisms through which affect acts to influence performance are unclear, it may determine the degree of physiological disruption that can be tolerated, or be reflective of peripheral physiological status in relation to the still to be completed exercise task.

scholarly journals Optimizing Interval Training Through Power-Output Variation Within the Work Intervals

2020 ◽  
Vol 15 (7) ◽  
pp. 982-989
Author(s):  
Arthur H. Bossi ◽  
Cristian Mesquida ◽  
Louis Passfield ◽  
Bent R. Rønnestad ◽  
James G. Hopker
Keyword(s):  
Oxygen Uptake ◽  
Power Output ◽  
Perceived Exertion ◽  
Minute Ventilation ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Interval Training ◽  
Training Load ◽  
Constant Intensity ◽  
Varied Intensity

Purpose: Maximal oxygen uptake () is a key determinant of endurance performance. Therefore, devising high-intensity interval training (HIIT) that maximizes stress of the oxygen-transport and -utilization systems may be important to stimulate further adaptation in athletes. The authors compared physiological and perceptual responses elicited by work intervals matched for duration and mean power output but differing in power-output distribution. Methods: Fourteen cyclists ( 69.2 [6.6] mL·kg−1·min−1) completed 3 laboratory visits for a performance assessment and 2 HIIT sessions using either varied-intensity or constant-intensity work intervals. Results: Cyclists spent more time at during HIIT with varied-intensity work intervals (410 [207] vs 286 [162] s, P = .02), but there were no differences between sessions in heart-rate- or perceptual-based training-load metrics (all P ≥ .1). When considering individual work intervals, minute ventilation () was higher in the varied-intensity mode (F = 8.42, P = .01), but not respiratory frequency, tidal volume, blood lactate concentration [La], ratings of perceived exertion, or cadence (all F ≤ 3.50, ≥ .08). Absolute changes (Δ) between HIIT sessions were calculated per work interval, and Δ total oxygen uptake was moderately associated with (r = .36, P = .002). Conclusions: In comparison with an HIIT session with constant-intensity work intervals, well-trained cyclists sustain higher fractions of when work intervals involved power-output variations. This effect is partially mediated by an increased oxygen cost of hyperpnea and not associated with a higher [La], perceived exertion, or training-load metrics.

A Comparison of Different Prerace Warm-Up Strategies on 1-km Cycling Time-Trial Performance

2020 ◽  
Vol 15 (8) ◽  
pp. 1109-1116
Author(s):  
Mathias T. Vangsoe ◽  
Jonas K. Nielsen ◽  
Carl D. Paton
Keyword(s):  
Blood Lactate ◽  
Power Output ◽  
Peak Power ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Time Trial ◽  
Peak Power Output ◽  
Warm Up ◽  
Performance Time ◽  
Competitive Cyclists

Purpose: Ischemic preconditioning (IPC) and postactivation potentiation (PAP) are warm-up strategies proposed to improve high-intensity sporting performance. However, only few studies have investigated the benefits of these strategies compared with an appropriate control (CON) or an athlete-selected (SELF) warm-up protocol. Therefore, this study examined the effects of 4 different warm-up routines on 1-km time-trial (TT) performance with competitive cyclists. Methods: In a randomized crossover study, 12 well-trained cyclists (age 32 [10] y, mass 77.7 [4.6] kg, peak power output 1141 [61] W) performed 4 different warm-up strategies—(CON) 17 minutes CON only, (SELF) a self-determined warm-up, (IPC) IPC + CON, or (PAP) CON + PAP—prior to completing a maximal-effort 1-km TT. Performance time and power, quadriceps electromyograms, muscle oxygen saturation (SmO2), and blood lactate were measured to determine differences between trials. Results: There were no significant differences (P > .05) in 1-km performance time between CON (76.9 [5.2] s), SELF (77.3 [6.0] s), IPC (77.0 [5.5] s), or PAP (77.3 [5.9] s) protocols. Furthermore, there were no significant differences in mean or peak power output between trials. Finally, electromyogram activity, SmO2, and recovery blood lactate concentration were not different between conditions. Conclusions: Adding IPC or PAP protocols to a short CON warm-up appears to provide no additional benefit to 1-km TT performance with well-trained cyclists and is therefore not recommended. Furthermore, additional IPC and PAP protocols had no effect on electromyograms and SmO2 values during the TT or peak lactate concentration during recovery.

Substrate-turnover interrelationships in fasting neonatal dogs

1980 ◽  
Vol 239 (4) ◽  
pp. E287-E287 ◽  
Keyword(s):  
Blood Glucose ◽  
Fasting Blood Glucose ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Glucose Turnover ◽  
Lactate Turnover ◽  
Lower Blood ◽  
Lactate Utilization ◽  
Blood Glucose Concentrations ◽  
The Relationship

Substrate-turnover relationships were determined in unanesthetized healthy fasted neonatal dogs during the first day of life. Pups were born at term by cesarean section to starved or control mothers. Pups born to starved mothers developed significantly lower blood glucose concentrations during neonatal fasting. In all pups, blood glucose concentrations during neonatal fasting. In all pups, blood glucose concentrations correlated to glucose utilization (r = 0.462, P < 0.001). Blood lactate concentration was significantly related to its turnover. The relationship between lactate turnover and lactate carbon appearance into glucose was significantly correlated. However, the relationship between lactate concentration and its carbon incorporation into glucose was only significant at 24 h of age in pups born to starved mothers. These data suggest that the neonatal dog is capable of regulating its glucose and lactate utilization by the availability of substrate. Because peripheral insulin levels correlated poorly to fasting blood glucose and glucose turnover; it is doubtful whether insulin secretion plays a significant role in fasting neonatal canine glucose homeostasis.

Association Between Deoxygenated Hemoglobin Breaking Point, Anaerobic Threshold, and Rowing Performance

2019 ◽  
Vol 14 (8) ◽  
pp. 1103-1109
Author(s):  
Tiago Turnes ◽  
Rafael Penteado dos Santos ◽  
Rafael Alves de Aguiar ◽  
Thiago Loch ◽  
Leonardo Trevisol Possamai ◽  
...  
Keyword(s):  
Heart Rate ◽  
Anaerobic Threshold ◽  
Power Output ◽  
Vastus Lateralis ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Breaking Point ◽  
Vastus Lateralis Muscle ◽  
Incremental Test ◽  
Deoxygenated Hemoglobin

Purpose: To compare the intensity and physiological responses of deoxygenated hemoglobin breaking point ([HHb]BP) and anaerobic threshold (AnT) during an incremental test and to verify their association with 2000-m rowing-ergometer performance in well-trained rowers. Methods: A total of 13 male rowers (mean [SD] age = 24 [11] y and  = 63.7 [6.1] mL·kg−1·min−1) performed a step incremental test. Gas exchange, vastus lateralis [HHb], and blood lactate concentration were measured. Power output, , and heart rate of [HHb]BP and AnT were determined and compared with each other. A 2000-m test was performed in another visit. Results: No differences were found between [HHb]BP and AnT in the power output (236 [31] vs 234 [31] W; Δ = 0.7%), 95% confidence interval [CI] 6.7%), (4.2 [0.5] vs 4.3 [0.4] L·min−1; Δ = −0.8%, 95% CI 4.0%), or heart rate (180 [16] vs 182 [12] beats·min−1; Δ = −1.6%, 95% CI 2.1%); however, there was high typical error of estimate (TEE) and wide 95% limits of agreement (LoA) for power output (TEE 10.7%, LoA 54.1–50.6 W), (TEE 5.9%, LoA −0.57 to 0.63 L·min−1), and heart rate (TEE 2.4%, LoA −9.6 to 14.7 beats·min−1). Significant correlations were observed between [HHb]BP (r = .70) and AnT (r = .89) with 2000-m mean power. Conclusions: These results demonstrate a breaking point in [HHb] of the vastus lateralis muscle during the incremental test that is capable of distinguishing rowers with different performance levels. However, the high random error would compromise the use of [HHb]BP for training and testing in rowing.

scholarly journals Effect of acute severe hypoxia on peripheral fatigue and endurance capacity in healthy humans

2007 ◽  
Vol 292 (1) ◽  
pp. R598-R606 ◽  
Author(s):  
Lee M. Romer ◽  
Hans C. Haverkamp ◽  
Markus Amann ◽  
Andrew T. Lovering ◽  
David F. Pegelow ◽  
...  
Keyword(s):  
Lactate Concentration ◽  
Femoral Nerve ◽  
Blood Lactate Concentration ◽  
Severe Hypoxia ◽  
Peripheral Fatigue ◽  
Time To Exhaustion ◽  
Endurance Capacity ◽  
Twitch Force ◽  
Healthy Humans ◽  
Locomotor Muscles

We hypothesized that severe hypoxia limits exercise performance via decreased contractility of limb locomotor muscles. Nine male subjects [mean ± SE maximum O2 uptake (V̇o2 max) = 56.5 ± 2.7 ml·kg−1·min−1] cycled at ≥90% V̇o2 max to exhaustion in normoxia [NORM-EXH; inspired O2 fraction (FiO2) = 0.21, arterial O2 saturation (SpO2) = 93 ± 1%] and hypoxia (HYPOX-EXH; FiO2 = 0.13, SpO2 = 76 ± 1%). The subjects also exercised in normoxia for a time equal to that achieved in hypoxia (NORM-CTRL; SpO2 = 96 ± 1%). Quadriceps twitch force, in response to supramaximal single (nonpotentiated and potentiated 1 Hz) and paired magnetic stimuli of the femoral nerve (10–100 Hz), was assessed pre- and at 2.5, 35, and 70 min postexercise. Hypoxia exacerbated exercise-induced peripheral fatigue, as evidenced by a greater decrease in potentiated twitch force in HYPOX-EXH vs. NORM-CTRL (−39 ± 4 vs. −24 ± 3%, P < 0.01). Time to exhaustion was reduced by more than two-thirds in HYPOX-EXH vs. NORM-EXH (4.2 ± 0.5 vs. 13.4 ± 0.8 min, P < 0.01); however, peripheral fatigue was not different in HYPOX-EXH vs. NORM-EXH (−34 ± 4 vs. −39 ± 4%, P > 0.05). Blood lactate concentration and perceptions of limb discomfort were higher throughout HYPOX-EXH vs. NORM-CTRL but were not different at end-exercise in HYPOX-EXH vs. NORM-EXH. We conclude that severe hypoxia exacerbates peripheral fatigue of limb locomotor muscles and that this effect may contribute, in part, to the early termination of exercise.

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