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.

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.

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.

Influence of endurance training on muscle [PCr] kinetics during high-intensity exercise

2007 ◽  
Vol 293 (1) ◽  
pp. R392-R401 ◽  
Author(s):  
Andrew M. Jones ◽  
Daryl P. Wilkerson ◽  
Nicolas J. Berger ◽  
Jonathan Fulford
Keyword(s):  
Endurance Training ◽  
High Intensity ◽  
Slow Component ◽  
Knee Extension ◽  
High Intensity Exercise ◽  
Whole Body ◽  
Time To Exhaustion ◽  
Exercise Tests ◽  
Before And After ◽  
Knee Extension Exercise

We hypothesized that a period of endurance training would result in a speeding of muscle phosphocreatine concentration ([PCr]) kinetics over the fundamental phase of the response and a reduction in the amplitude of the [PCr] slow component during high-intensity exercise. Six male subjects (age 26 ± 5 yr) completed 5 wk of single-legged knee-extension exercise training with the alternate leg serving as a control. Before and after the intervention period, the subjects completed incremental and high-intensity step exercise tests of 6-min duration with both legs separately inside the bore of a whole-body magnetic resonance spectrometer. The time-to-exhaustion during incremental exercise was not changed in the control leg [preintervention group (PRE): 19.4 ± 2.3 min vs. postintervention group (POST): 19.4 ± 1.9 min] but was significantly increased in the trained leg (PRE: 19.6 ± 1.6 min vs. POST: 22.0 ± 2.2 min; P < 0.05). During step exercise, there were no significant changes in the control leg, but end-exercise pH and [PCr] were higher after vs. before training. The time constant for the [PCr] kinetics over the fundamental exponential region of the response was not significantly altered in either the control leg (PRE: 40 ± 13 s vs. POST: 43 ± 10 s) or the trained leg (PRE: 38 ± 8 s vs. POST: 40 ± 12 s). However, the amplitude of the [PCr] slow component was significantly reduced in the trained leg (PRE: 15 ± 7 vs. POST: 7 ± 7% change in [PCr]; P < 0.05) with there being no change in the control leg (PRE: 13 ± 8 vs. POST: 12 ± 10% change in [PCr]). The attenuation of the [PCr] slow component might be mechanistically linked with enhanced exercise tolerance following endurance training.

scholarly journals Comprehensive exercise training improves ventilatory muscle function and reduces dyspnea perception in patients with COPD

2016 ◽  
Vol 71 (3) ◽  
Author(s):  
F. Cortopassi ◽  
A.A.M. Castro ◽  
E.F. Porto ◽  
M. Colucci ◽  
G. Fonseca ◽  
...  
Keyword(s):  
Exercise Training ◽  
Respiratory Muscles ◽  
Exercise Programme ◽  
Lower Limbs ◽  
Test Time ◽  
Chronic Obstructive ◽  
Endurance Test ◽  
Incremental Test ◽  
Copd Patients ◽  
Before And After

Background. Comprehensive exercise training (CET) is an efficient strategy to decrease dyspnea perception in chronic obstructive pulmonary disease (COPD) and may result in significant improvement in ventilatory muscles function. Our aim was to evaluate the effects of general exercise training on dyspnea perception and on respiratory muscles strength in COPD patients. Methods. Consecutive COPD patients were enrolled to complete a CET programme. The patients underwent a routine that included a global warm up, upper and lower limbs endurance exercise as well as stretching and relaxation. Before and after the CET programme, patients completed maximal inspiratory (PImax) and expiratory (PEmax) pressures measurements, maximal incremental test, endurance test, and 6-min walk distance (6MWD). Results. 71 patients (52 male). Mean age 67.6±8.6 years, FEV1 (%) 44.2±16.2 and Mahler dyspnea scale 6.4±1.8. The results before and after the exercise programme were: PImax 64.7±22.9 vs. 75.5±23.7 cmH2O (p=0.001), PEmax 110.8±28.1 vs. 120.4±28.1 cmH2O (p=0.004), 6MWD 510.6±90.3 vs. 528.2±99.7 metres (p=0.88), time of incremental test 672±135 vs. 856±226 sec (p&lt;0.0001). Compared with the pre exercise programme, we observed a significant reduction on Borg dyspnea scale (6.1±2.8 to 3.6±2.3, p&lt;0.0001) as well as a longer test time (504±218 to 1.038±841, p&lt;0.0001) at the end of the endurance test after CET programme. Improvement of PImax correlated negatively with dyspnea perception at iso-time during the endurance test (r= -0.33, p=0.03). Conclusions. Our results confirm that CET is associated with significant improvement in PImax, PEmax and provide evidence demonstrating that CET reduces dyspnea perception in patients with COPD.

scholarly journals A new physical performance classification system for elite handball players: cluster analysis

2016 ◽  
Vol 51 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Iker J. Bautista ◽  
Ignacio J. Chirosa ◽  
Joseph E. Robinson ◽  
Roland van der Tillaar ◽  
Luis J. Chirosa ◽  
...  
Keyword(s):  
Physical Performance ◽  
Peak Power ◽  
Bench Press ◽  
National Level ◽  
Test Results ◽  
Countermovement Jump ◽  
Mean Power ◽  
Squat Jump ◽  
Power Load ◽  
The Mean

Abstract The aim of the present study was to identify different cluster groups of handball players according to their physical performance level assessed in a series of physical assessments, which could then be used to design a training program based on individual strengths and weaknesses, and to determine which of these variables best identified elite performance in a group of under-19 [U19] national level handball players. Players of the U19 National Handball team (n=16) performed a set of tests to determine: 10 m (ST10) and 20 m (ST20) sprint time, ball release velocity (BRv), countermovement jump (CMJ) height and squat jump (SJ) height. All players also performed an incremental-load bench press test to determine the 1 repetition maximum (1RMest), the load corresponding to maximum mean power (LoadMP), the mean propulsive phase power at LoadMP (PMPPMP) and the peak power at LoadMP (PPEAKMP). Cluster analyses of the test results generated four groupings of players. The variables best able to discriminate physical performance were BRv, ST20, 1RMest, PPEAKMP and PMPPMP. These variables could help coaches identify talent or monitor the physical performance of athletes in their team. Each cluster of players has a particular weakness related to physical performance and therefore, the cluster results can be applied to a specific training programmed based on individual needs.

scholarly journals The Acute Post-Activation Performance Enhancement of the Bench Press Throw in Disabled Sitting Volleyball Athletes

2021 ◽  
Vol 18 (7) ◽  
pp. 3818
Author(s):  
Michal Krzysztofik ◽  
Patryk Matykiewicz ◽  
Diana Celebanska ◽  
Jakub Jarosz ◽  
Eliza Gawel ◽  
...  
Keyword(s):  
Body Mass ◽  
Repeated Measures ◽  
Peak Power ◽  
Bench Press ◽  
Performance Enhancement ◽  
Peak Power Output ◽  
Volleyball Players ◽  
Before And After ◽  
Bar Velocity ◽  
Post Hoc

The purpose of the present study was to examine the acute effects of the bench press exercise with predetermined velocity loss percentage on subsequent bench press throw (BPT) performance with raised legs or feet on the floor among disabled, sitting volleyball players. Twelve elite sitting volleyball athletes (age = 33 ± 9 years; body mass = 84.7 ± 14.7 kg; relative bench press maximum strength = 1.0 ± 0.3 kg/body mass) took part in this study. The experiment was performed following a randomized crossover design, where each participant performed a single set of bench press with a 60% one-repetition maximum (1RM) to a 10% decrease of mean bar velocity as a conditioning activity (CA). The BPT with a 60%1RM was performed to assess changes in peak power (PP), peak velocity (PV) before and after the CA. The differences between analyzed variables before and after the CA were verified using two-way repeated-measures ANOVA (condition × time; 2 × 2). The ANOVA showed a significant main effect of time for peak bar velocity (p = 0.03; η2 = 0.312) and peak power output (p = 0.037; η2 = 0.294). The post hoc comparison showed a significant increase in post-CA peak bar velocity and peak power for raised legs condition in comparison with pre-CA value (p = 0.02, p = 0.041, respectively). The present study showed that the subsequent BPT performed with raised legs could be enhanced by the bench press with a 60% 1RM to a 10% mean bar velocity decrease as a CA among disabled sitting volleyball players. Therefore, athletes and coaches can consider performing a bench press throw with raised legs without compromising performance.

scholarly journals The effect of moderate versus high intensity exercise on heart rate variability in sedentary office workers

2021 ◽  
Vol 16 (1) ◽  
pp. 16-23
Author(s):  
Vibha Gangwar ◽  
Manish Kumar Verma ◽  
Ritesh Singh Gangwar ◽  
Nitin Ashok John ◽  
Rajani Bala Jasrotia
Keyword(s):  
Heart Rate ◽  
Exercise Training ◽  
High Intensity ◽  
High Intensity Exercise ◽  
Office Workers ◽  
Moderate Intensity ◽  
Moderate Intensity Exercise ◽  
Group I ◽  
Before And After ◽  
Group Ii

Background: Sedentary behavior is one of the leading modifiable risk factors for cardiovascular disease and all-cause mortality. Physical exercise exerts beneficial physiological effects on cardiovascular fitness. Different grades of physical exercise have different effects on cardiovascular health. Objective: To compare the effect of moderate and high intensity exercise training on heart rate variability (HRV) in sedentary office workers. Methods: This study was conducted on 40 healthy sedentary volunteers aged between 20-40 years of both the genders. Participants were distributed into two groups of 20 subjects each. Subjects of group I and group II performed moderate intensity and high intensity exercise respectively on bicycle ergometer for 12 weeks. Their 5- minute ECG recording was done by three channel physiograph, and frequency domain indices of HRV and heart rate (HR) were analyzed and compared before and after exercise training. Their blood pressure was also recorded and compared before and after exercise training. Independent sample t-test and paired sample ttest were used for statistical analysis. Results: HF, systolic and diastolic blood pressure reduced significantly after exercise in group II (p=0.015, 0.005, and 0.015 respectively) while HR and LF/HF ratio reduced in both group I and group II (p=0.000 for HR, and 0.034, 0.001 for LF/HF). The decrease in HR was greater after high intensity exercise than moderate intensity exercise (p= 0.025). Conclusion: Parasympathetic activity improves after moderate and high intensity exercise but improvement is more after high intensity exercise training. Therefore, high intensity exercise training is more beneficial than moderate intensity exercise training. J Bngladesh Soc Physiol 2021;16(1): 16-23

scholarly journals The Reliability of Measuring Gross Efficiency During High-Intensity Cycling Exercise

2020 ◽  
Vol 15 (1) ◽  
pp. 126-132
Author(s):  
Richard Ebreo ◽  
Louis Passfield ◽  
James Hopker
Keyword(s):  
Oxygen Consumption ◽  
High Intensity ◽  
Aerobic Power ◽  
Maximal Aerobic Power ◽  
Limits Of Agreement ◽  
Cycling Exercise ◽  
Gross Efficiency ◽  
Before And After ◽  
Excess Postexercise Oxygen Consumption ◽  
Aerobic And Anaerobic

Purpose: To evaluate the reliability of calculating gross efficiency (GE) conventionally and using a back extrapolation (BE) method during high-intensity exercise (HIE). Methods: A total of 12 trained participants completed 2 HIE bouts (P1 = 4 min at 80% maximal aerobic power [MAP]; P2 = 4 min at 100%MAP). GE was calculated conventionally in the last 3 minutes of submaximal (50%MAP) cycling bouts performed before and after HIE (Pre50%MAP and Post50%MAP). To calculate GE using BE (BGE), a linear regression of GE submaximal values post-HIE were back extrapolated to the end of the HIE bout. Results: BGE was significantly correlated with Post50%MAP GE in P1 (r = .63; P = .01) and in P2 (r = .85; P = .002). Reliability data for P1 and P2 BGE demonstrate a mean coefficient of variation of 7.8% and 9.8% with limits of agreement of 4.3% and 4.5% in relative GE units, respectively. P2 BGE was significantly lower than P2 Post50%MAP GE (18.1% [1.6%] vs 20.3% [1.7%]; P = .01). Using a declining GE from the BE method, there was a 44% greater anaerobic contribution compared with assuming a constant GE during 4-minute HIE at 100%MAP. Conclusion: HIE acutely reduced BGE at 100%MAP. A greater anaerobic contribution to exercise as well as excess postexercise oxygen consumption at 100%MAP may contribute to this decline in efficiency. The BE method may be a reliable and valid tool in both estimating GE during HIE and calculating aerobic and anaerobic contributions.

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