An Approach to Estimating Gross Efficiency During High-Intensity Exercise

2013 ◽  
Vol 8 (6) ◽  
pp. 682-684 ◽  
Author(s):  
Jos J. de Koning ◽  
Dionne A. Noordhof ◽  
Tom P. Uitslag ◽  
Rianna E Galiart ◽  
Christopher Dodge ◽  
...  
Keyword(s):  
High Intensity ◽  
Peak Power ◽  
Power Production ◽  
Submaximal Exercise ◽  
High Intensity Exercise ◽  
Peak Power Output ◽  
Control Test ◽  
Incremental Test ◽  
Gross Efficiency ◽  
Determining Factor

Purpose:Gross efficiency (GE) is coupling power production to propulsion and is an important performance-determining factor in endurance sports. Measuring GE normally requires measuring VO2 during submaximal exercise. In this study a method is proposed to estimating GE during high-intensity exercise.Methods:Nineteen subjects completed a maximal incremental test and 2 GE tests (1 experimental and 1 control test). The GE test consisted of 10 min cycling at 50% peak power output (PPO), 2 min at 25 W, followed by 4 min 100% PPO, 1 min at 25 W, and another 10 min at 50% PPO. GE was determined for the 50%-PPO sections and was, for the second 50%-PPO section, back-extrapolated, using linear regression, to the end of the 100%-PPO bout.Results:Back-extrapolation of the GE data resulted in a calculated GE of 15.8% ± 1.7% at the end of the 100%-PPO bout, in contrast to 18.3% ± 1.3% during the final 2 min of the first 10-min 50%-PPO bout.Conclusion:Back-extrapolation seems valuable in providing more insight in GE during high-intensity exercise.

Changes in Technique and Efficiency After High-Intensity Exercise in Cross-Country Skiers

2014 ◽  
Vol 9 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Christina Åsan Grasaas ◽  
Gertjan Ettema ◽  
Ann Magdalen Hegge ◽  
Knut Skovereng ◽  
Øyvind Sandbakk
Keyword(s):  
High Intensity ◽  
Peak Power ◽  
Bench Press ◽  
High Intensity Exercise ◽  
Lower Limbs ◽  
Incremental Test ◽  
Squat Jump ◽  
Gross Efficiency ◽  
Before And After ◽  
Cross Country

This study investigated changes in technique and efficiency after high-intensity exercise to exhaustion in elite cross-country skiers. Twelve elite male skiers completed 4 min submaximal exercise before and after a high-intensity incremental test to exhaustion with the G3 skating technique on a 5% inclined roller-ski treadmill. Kinematics and kinetics were monitored by instrumented roller skis, work rate was calculated as power against roller friction and gravity, aerobic metabolic cost was determined from gas exchange, and blood lactate values indicated the anaerobic contribution. Gross efficiency was the work rate divided by aerobic metabolic rate. A recovery period of 10 min between the incremental test and the posttest was included to allow the metabolic values to return to baseline. Changes in neuromuscular fatigue in upper and lower limbs before and after the incremental test were indicated by peak power in concentric bench press and squat-jump height. From pretest to posttest, cycle length decreased and cycle rate increased by approximately 5% (P < 0.001), whereas the amount of ski forces did not change significantly. Oxygen uptake increased by 4%, and gross efficiency decreased from 15.5% ± 0.7% to 15.2% ± 0.5% from pretest to posttest (both P < .02). Correspondingly, blood lactate concentration increased from 2.4 ± 1.0 to 6.2 ± 2.5 mmol/L (P < .001). Bench-press and squat-jump performance remained unaltered. Elite cross-country skiers demonstrated a less efficient technique and shorter cycle length during submaximal roller-ski skating after high-intensity exercise. However, there were no changes in ski forces or peak power in the upper and lower limbs that could explain these differences.

Recovery of Cycling Gross Efficiency After Time-Trial Exercise

2018 ◽  
Vol 13 (8) ◽  
pp. 1028-1033 ◽  
Author(s):  
Sjors Groot ◽  
Lars H.J. van de Westelaken ◽  
Dionne A. Noordhof ◽  
Koen Levels ◽  
Jos J. de Koning
Keyword(s):  
High Intensity ◽  
Time Course ◽  
Time Trial ◽  
Exercise Bout ◽  
Submaximal Exercise ◽  
High Intensity Exercise ◽  
Cycling Exercise ◽  
Gross Efficiency ◽  
Before And After ◽  
The Difference

Background: Research has shown that gross efficiency (GE) declines during high-intensity exercise, but the time course of recovery of GE after high-intensity exercise has not yet been investigated. Purpose: To determine the time course of the recovery of GE after time trials (TTs) of different lengths. Methods: Nineteen trained male cyclists participated in this study. Before and after TTs of 2000 and 20,000 m, subjects performed submaximal exercise at 55% of the power output attained at maximal oxygen uptake (PVO2max). The postmeasurement continued until 30 min after the end of the TT, during which GE was determined over 3-min intervals. The magnitude-based-inferences approach was used for statistical analysis. Results: GE decreased substantially during the 2000-m and 20,000-m TTs (−11.8% [3.6%] and −6.2% [4.0%], respectively). A most likely and very likely recovery of GE was found during the first half of the submaximal exercise bout performed after the 2000-m, with only a possible increase in GE during the first part of the submaximal exercise bout performed after the 20,000-m. After both distances, GE did not fully recover to the initial pre-TT values, as the difference between the pre-TT value and average GE value of minutes 26–29 was still most likely negative for both the 2000- and 20,000-m (−6.1% [2.8%] and −7.0% [4.5%], respectively). Conclusions: It is impossible to fully recover GE after TTs of 2000- or 20,000-m during 30 min of submaximal cycling exercise performed at an intensity of 55% PVO2max.

scholarly journals Energy Expenditure Equation Choice: Effects on Cycling Efficiency and its Reliability

2020 ◽  
Vol 15 (2) ◽  
pp. 288-291
Author(s):  
Arthur H. Bossi ◽  
Wouter P. Timmerman ◽  
James G. Hopker
Keyword(s):  
Energy Expenditure ◽  
Peak Power ◽  
Peak Power Output ◽  
Physiological Profile ◽  
Gas Exchanges ◽  
Gross Efficiency ◽  
Reliability Parameters ◽  
Cycling Efficiency ◽  
The Mean ◽  
Gas Exchange Threshold

Purpose: There are several published equations to calculate energy expenditure (EE) from gas exchanges. The authors assessed whether using different EE equations would affect gross efficiency (GE) estimates and their reliability. Methods: Eleven male and 3 female cyclists (age 33 [10] y; height: 178 [11] cm; body mass: 76.0 [15.1] kg; maximal oxygen uptake: 51.4 [5.1] mL·kg−1·min−1; peak power output: 4.69 [0.45] W·kg−1) completed 5 visits to the laboratory on separate occasions. In the first visit, participants completed a maximal ramp test to characterize their physiological profile. In visits 2 to 5, participants performed 4 identical submaximal exercise trials to assess GE and its reliability. Each trial included three 7-minute bouts at 60%, 70%, and 80% of the gas exchange threshold. EE was calculated with 4 equations by Péronnet and Massicotte, Lusk, Brouwer, and Garby and Astrup. Results: All 4 EE equations produced GE estimates that differed from each other (all P < .001). Reliability parameters were only affected when the typical error was expressed in absolute GE units, suggesting a negligible effect—related to the magnitude of GE produced by each EE equation. The mean coefficient of variation for GE across different exercise intensities and calculation methods was 4.2%. Conclusions: Although changing the EE equation does not affect GE reliability, exercise scientists and coaches should be aware that different EE equations produce different GE estimates. Researchers are advised to share their raw data to allow for GE recalculation, enabling comparison between previous and future studies.

Reducing Anxiety and Anxiety Sensitivity With High-Intensity Interval Training in Adults With Asthma

2020 ◽  
Vol 17 (8) ◽  
pp. 835-839
Author(s):  
Carley O’Neill ◽  
Shilpa Dogra
Keyword(s):  
Anxiety Sensitivity ◽  
Power Output ◽  
High Intensity ◽  
Peak Power ◽  
Interval Training ◽  
Peak Power Output ◽  
Sensitivity Index ◽  
High Intensity Interval Training ◽  
High Intensity Interval ◽  
The Impact

Background: Low- and moderate-intensity exercise training has been shown to be effective for reducing general anxiety and anxiety sensitivity among adults with asthma. Exercise frequency and intensity have been shown to play an integral role in reducing anxiety sensitivity; however, less is known about the impact of high-intensity interval training (HIIT) on anxiety in adults with asthma. Methods: A 6-week HIIT intervention was conducted with adults with asthma. Participants completed HIIT (10% peak power output for 1 min, 90% peak power output for 1 min, repeated 10 times) 3 times per week on a cycle ergometer. Preintervention and postintervention assessments included the Anxiety Sensitivity Index-3 and the Body Sensations Questionnaire. Results: Total Anxiety Sensitivity Index-3 (PRE: 17.9 [11.8]; POST 12.4 [13], P = .002, Cohen d = 0.4, n = 20) and Body Sensations Questionnaire (PRE: 2.4 [1.0]; POST: 2.0 [0.8], P = .007, Cohen d = 0.3) improved from preintervention to postintervention. Conclusion: A 6-week HIIT intervention leads to improved anxiety among adults with asthma. Future research should determine the impact of HIIT among adults with asthma with clinical anxiety.

Power loss is attenuated following a second bout of high intensity eccentric contractions due to the repeated bout effect’s protection of rate of torque and velocity development

2020 ◽  
Author(s):  
Avery Hinks ◽  
Adam Hess ◽  
Mathew I. B. Debenham ◽  
Jackey Chen ◽  
Nicole Mazara ◽  
...  
Keyword(s):  
Muscle Damage ◽  
Eccentric Exercise ◽  
High Intensity ◽  
Power Loss ◽  
Peak Power ◽  
Eccentric Contractions ◽  
Peak Power Output ◽  
Repeated Bout Effect ◽  
Maximum Voluntary Isometric Contraction ◽  
Repeated Bout

High intensity unaccustomed eccentric contractions result in weakness and power loss due to fatigue and muscle damage. Through the repeated bout effect (RBE), adaptations occur, then damage and weakness are attenuated following a subsequent bout. However, it is unclear whether the RBE protects peak power output. We investigated the influence of the RBE on power production and estimated fatigue- and damage-induced neuromuscular impairments following repeated high-intensity eccentric contractions. Twelve healthy adult males performed 5 sets of 30 maximal eccentric elbow flexions and repeated an identical bout 4 weeks later. Recovery was tracked over 7 days following both bouts. Reduced maximum voluntary isometric contraction torque, and increased serum creatine kinase and self-reported soreness indirectly inferred muscle damage. Peak isotonic power, time-dependent measures—rate of velocity development (RVD) and rate of torque development (RTD)—and several electrophysiological indices of neuromuscular function were assessed. The RBE protected peak power, with a protective index of 66% 24 hours after the second eccentric exercise bout. The protection of power also related to preserved RVD (R2=0.61, P<0.01) and RTD (R2=0.39, P<0.01). Furthermore, the RBE’s protection against muscle damage permitted the estimation of fatigue-associated neuromuscular performance decrements following eccentric exercise. Novelty Bullets • The repeated bout effect protects peak isotonic power. • Protection of peak power relates to preserved rates of torque and velocity development, but more so rate of velocity development. • The repeated bout effect has little influence on indices of neuromuscular fatigue.

scholarly journals High tempo music prolongs high intensity exercise

PeerJ ◽  
2019 ◽  
Vol 6 ◽  
pp. e6164 ◽  
Author(s):  
Meaghan E. Maddigan ◽  
Kathleen M. Sullivan ◽  
Israel Halperin ◽  
Fabien A. Basset ◽  
David G. Behm
Keyword(s):  
High Intensity ◽  
Peak Power ◽  
Perceived Exertion ◽  
Rating Of Perceived Exertion ◽  
Moderate Intensity ◽  
Peak Power Output ◽  
Breathing Frequency ◽  
Post Exercise ◽  
End Point ◽  
Exercise Enjoyment

Music has been shown to reduce rating of perceived exertion, increase exercise enjoyment and enhance exercise performance, mainly in low-moderate intensity exercises. However, the effects of music are less conclusive with high-intensity activities. The purpose of this with-participant design study was to compare the effects of high tempo music (130 bpm) to a no-music condition during repeated high intensity cycling bouts (80% of peak power output (PPO)) on the following measures: time to exercise end-point, rating of perceived exertion (RPE), heart rate (HR), breathing frequency, ventilatory kinetics and blood lactate (BL). Under the music condition, participants exercised 10.7% longer (p = 0.035; Effect size (ES) = 0.28) (increase of 1 min) and had higher HR (4%; p = 0.043; ES = 0.25), breathing frequency (11.6%; p < 0.001; ES = 0.57), and RER (7% at TTF; p = 0.021; ES = 1.1) during exercise, as measured at the exercise end-point. Trivial differences were observed between conditions in RPE and other ventilatory kinetics during exercise. Interestingly, 5 min post-exercise termination, HR recovery was 13.0% faster following the music condition (p < 0.05) despite that music was not played during this period. These results strengthen the notion that music can alter the association between central motor drive, central cardiovascular command and perceived exertion, and contribute to prolonged exercise durations at higher intensities along with a quicken HR recovery.

scholarly journals Influence of Intensity RAMP Incremental Test on Peak Power, Post-Exercise Blood Lactate, and Heart Rate Recovery in Males: Cross-Over Study

2019 ◽  
Vol 16 (20) ◽  
pp. 3934
Author(s):  
Kamil Michalik ◽  
Kuba Korta ◽  
Natalia Danek ◽  
Marcin Smolarek ◽  
Marek Zatoń
Keyword(s):  
Heart Rate ◽  
Blood Lactate ◽  
Peak Power ◽  
Design Method ◽  
Heart Rate Recovery ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Power Output ◽  
Maximal Heart Rate ◽  
Incremental Test

Background: The linearly increased loading (RAMP) incremental test is a method commonly used to evaluate physical performance in a laboratory, but the best-designed protocol remains unknown. The aim of this study was to compare the selected variables used in training control resulting from the two different intensities of RAMP incremental tests. Methods: Twenty healthy and physically active men took part in this experiment. The tests included two visits to a laboratory, during which anthropometric measurements, incremental test on a cycle ergometer, and examinations of heart rate and blood lactate concentration were made. The cross-over study design method was used. The subjects underwent a randomly selected RAMP test with incremental load: 0.278 W·s−1 or 0.556 W·s−1. They performed the second test a week later. Results: Peak power output was significantly higher by 51.69 W (p < 0.001; t = 13.10; ES = 1.13) in the 0.556 W·s−1 group. Total work done was significantly higher in the 0.278 W·s−1 group by 71.93 kJ (p < 0.001; t = 12.55; ES = 1.57). Maximal heart rate was significantly higher in the 0.278 W·s−1 group by 3.30 bpm (p < 0.01; t = 3.72; ES = 0.48). There were no statistically significant differences in heart rate recovery and peak blood lactate. Conclusions: We recommend use of the 0.556 W·s−1 RAMP protocol because it is of shorter duration compared with 0.278 W·s−1 and as such practically easier and of less effort for subjects.

scholarly journals Hypoxia and the cardiovascular response to dynamic knee-extensor exercise

1997 ◽  
Vol 272 (6) ◽  
pp. H2655-H2663 ◽  
Author(s):  
M. D. Koskolou ◽  
J. A. Calbet ◽  
G. Radegran ◽  
R. C. Roach
Keyword(s):  
Cardiac Output ◽  
Peak Power ◽  
Cardiovascular Response ◽  
Knee Extensor ◽  
Submaximal Exercise ◽  
Peak Power Output ◽  
O2 Uptake ◽  
Aerobic Exercise Capacity ◽  
O2 Extraction ◽  
O2 Delivery

Hypoxia affects O2 transport and aerobic exercise capacity. In two previous studies, conflicting results have been reported regarding whether O2 delivery to the muscle is increased with hypoxia or whether there is a more efficient O2 extraction to allow for compensation of the decreased O2 availability at submaximal and maximal exercise. To reconcile this discrepancy, we measured limb blood flow (LBF), cardiac output, and O2 uptake during two-legged knee-extensor exercise in eight healthy young men. They completed studies at rest, at two submaximal workloads, and at peak effort under normoxia (inspired O2 fraction 0.21) and two levels of hypoxia (inspired O2 fractions 0.16 and 0.11). During submaximal exercise, LBF increased in hypoxia and compensated for the decrement in arterial O2 content. At peak effort, however, our subjects did not achieve a higher cardiac output or LBF. Thus O2 delivery was not maintained and peak power output and leg O2 uptake were reduced proportionately. These data are consistent then with the findings of an increased LBF to compensate for hypoxemia at submaximal exercise, but no such increase occurs at peak effort despite substantial cardiac capacity for an elevation in LBF.

Acceleration of V˙o 2kinetics in heavy submaximal exercise by hyperoxia and prior high-intensity exercise

1997 ◽  
Vol 83 (4) ◽  
pp. 1318-1325 ◽  
Author(s):  
Maureen Macdonald ◽  
Preben K. Pedersen ◽  
Richard L. Hughson
Keyword(s):  
High Intensity ◽  
Ventilatory Threshold ◽  
Slow Component ◽  
Submaximal Exercise ◽  
High Intensity Exercise ◽  
Total Change ◽  
Group Of Seven ◽  
Mean Response Time ◽  
Exercise Transitions ◽  
The Mean

MacDonald, Maureen, Preben K. Pedersen, and Richard L. Hughson. Acceleration ofV˙o 2 kinetics in heavy submaximal exercise by hyperoxia and prior high-intensity exercise. J. Appl. Physiol. 83(4): 1318–1325, 1997.—We examined the hypothesis that O2 uptake (V˙o 2) would change more rapidly at the onset of step work rate transitions in exercise with hyperoxic gas breathing and after prior high-intensity exercise. The kinetics ofV˙o 2 were determined from the mean response time (MRT; time to 63% of total change inV˙o 2) and calculations of O2 deficit and slow component during normoxic and hyperoxic gas breathing in one group of seven subjects during exercise below and above ventilatory threshold (VT) and in another group of seven subjects during exercise above VT with and without prior high-intensity exercise. In exercise transitions below VT, hyperoxic gas breathing did not affect the kinetic response of V˙o 2 at the onset or end of exercise. At work rates above VT, hyperoxic gas breathing accelerated both the on- and off-transient MRT, reduced the O2 deficit, and decreased theV˙o 2 slow component from minute 3 to minute 6 of exercise, compared with normoxia. Prior exercise above VT accelerated the on-transient MRT and reduced theV˙o 2 slow component from minute 3 to minute 6 of exercise in a second bout of exercise with both normoxic and hyperoxic gas breathing. However, the summated O2 deficit in the second normoxic and hyperoxic steps was not different from that of the first steps in the same gas condition. Faster on-transient responses in exercise above, but not below, VT with hyperoxia and, to a lesser degree, after prior high-intensity exercise above VT support the theory of an O2 transport limitation at the onset of exercise for workloads >VT.

Acute High-Intensity Interval Training Improves Tvent and Peak Power Output in Highly Trained Males

2002 ◽  
Vol 27 (4) ◽  
pp. 336-348 ◽  
Author(s):  
Paul B. Laursen ◽  
Michelle A. Blanchard ◽  
David G. Jenkins
Keyword(s):  
Oxygen Uptake ◽  
Power Output ◽  
High Intensity ◽  
Peak Power ◽  
Ventilatory Threshold ◽  
Interval Training ◽  
Peak Power Output ◽  
Control Group ◽  
High Intensity Interval Training ◽  
High Intensity Interval

This study examined the effects of four high-intensity interval-training (HIT) sessions performed over 2 weeks on peak volume of oxygen uptake [Formula: see text] the first and second ventilatory thresholds (VT1, VT2) and peak power output (PPO) in highly trained cyclists. Fourteen highly trained male cyclists [Formula: see text] performed a ramped cycle test to determine [Formula: see text]VT1, VT2, and PPO. Subjects were divided equally into a HIT group and a control group. The HIT group performed four HIT sessions (20 × 60 s at PPO, 120 s recovery); the [Formula: see text] test was repeated < 1 wk after the HIT program. Control subjects maintained their regular training program and were reassessed under the same timeline. There was no change in [Formula: see text] for either group; however, the HIT group showed a significantly greater increase in VT1 (+22% vs. −3%), VT2 (+15% vs. −1%), and PPO (+4.3 vs. −4%) compared to controls (all P < .05). This study has demonstrated that HIT can improve VT1, VT2 and PPO, following only four HIT sessions in already highly trained cyclists. Key words: cycling, cyclists, heart rate, oxygen uptake, short-term training, ventilatory threshold

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