Energy cost of and energy sources for alpine skiing in top athletes

1984 ◽  
Vol 56 (5) ◽  
pp. 1187-1190 ◽  
Author(s):  
A. Veicsteinas ◽  
G. Ferretti ◽  
V. Margonato ◽  
G. Rosa ◽  
D. Tagliabue
Keyword(s):  
Energy Cost ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Energy Sources ◽  
Alpine Skiing ◽  
O2 Uptake ◽  
Male Athletes ◽  
Energy Equivalent ◽  
Expenditure Rate ◽  
Study Heart Rate

O2 uptake (VO2) during exercise and at 2 min of the recovery along with blood lactate concentration 5 min after exercise were measured in an all-out special slalom (SS) and giant slalom (GS) performed by eight top male athletes and five controls in a field study. Heart rate (HR) was continuously monitored before, during, and after each task. On the basis of an energy equivalent of 3.15 ml O2 X kg body wt-1 for 1 mmol X 1–1 lactate accumulation and the assumption that the amount of O2 consumed in recovery is used to reconstitute approximately phosphates used during the exercise, the total energy cost (delta VO2 tot) could be calculated and subdivided into aerobic, lactic, and alactic fractions. In top athletes, delta VO2 tot was equal during SS and GS [7.28 +/- 1.14 (SD) and 7.47 +/- 0.89 liters for about 55- and 70-s performances, respectively]. When referred to time, the O2 expenditure rate was 2 and 1.6 times VO2max in SS and GS, respectively. In SS and GS, the energy sources were about 40% aerobic, 20% alactic , and 40% lactic metabolism. In control skiers, delta VO2 tot of GS was 6.12 +/- 1.45 liters for 77 s, amounting to about 1.3 VO2max, with the contribution of the different energy sources being roughly the same as in top skiers. HR reached maximal values in 30–40 s in all subjects for all conditions.

Exercise recovery above and below anaerobic threshold following maximal work

1981 ◽  
Vol 51 (4) ◽  
pp. 840-844 ◽  
Author(s):  
B. A. Stamford ◽  
A. Weltman ◽  
R. Moffatt ◽  
S. Sady
Keyword(s):  
Blood Lactate ◽  
Anaerobic Threshold ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Base Line ◽  
Exercise Recovery ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Individual Subject

The purpose of this study was to determine the effects of resting and exercise recovery above [70% of maximum O2 uptake (VO2 max)] and below [40% of VO2 max] anaerobic threshold (AT) on blood lactate disappearance following maximal exercise. Blood lactate concentrations at rest (0.9 mM) and during exercise at 40% (1.3 mM) and 70% (3.5 mM) of VO2 max without preceding maximal exercise were determined on separate occasions and represented base lines for each condition. The rate of blood lactate disappearance from peak values was ascertained from single-component exponential curves fit for each individual subject for each condition using both the determined and resting base lines. When determined base lines were utilized, there were no significant differences in curve parameters between the 40 and 70% of VO2 max recoveries, and both were significantly different from the resting recovery. When a resting base line (0.9 mM) was utilized for all conditions, 40% of VO2 max demonstrated a significantly faster half time than either 70% of VO2 max or resting recovery. No differences were found between 70% of VO2 max and resting recovery. It was concluded that interpretation of the effectiveness of exercise recovery above and below AT with respect to blood lactate disappearance is influenced by the base-line blood lactate concentration utilized in the calculation of exponential half times.

scholarly journals Physiological responses to partial-body cryotherapy performed during a concurrent strength and endurance session

2019 ◽  
Vol 44 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Alessandro Piras ◽  
Francesco Campa ◽  
Stefania Toselli ◽  
Rocco Di Michele ◽  
Milena Raffi
Keyword(s):  
Oxygen Uptake ◽  
Strength Training ◽  
Energy Cost ◽  
Minute Ventilation ◽  
Lactate Concentration ◽  
Training Session ◽  
Blood Lactate Concentration ◽  
Hydration Status ◽  
Passive Recovery ◽  
Partial Body

This investigation examined the effect of partial-body cryostimulation (PBC) performed in the recovery time between a strength training and an interval running (IR) session. Nine rugby players (age, 23.7 ± 3.6 years; body mass index, 28.0 ± 2.6 kg·m−2) were randomly exposed to 2 different conditions: (i) PBC: 3 min at −160 °C, and (ii) passive recovery at 21 °C. We performed the bioelectrical impedance analysis (BIA) and recorded temperature and cardiac autonomic variables at 3 time points: at baseline, after strength training, and after 90 min of recovery. In addition, blood lactate concentration was measured 1 min before and 2.5 min after the IR. Heart rate (HR), energy cost, minute ventilation, oxygen uptake, and metabolic power were assessed during the IR. Homeostatic hydration status was affected by the execution of an intense strength training subsession. Then, after PBC, the BIA vector was restored close to normohydration status. Autonomic variables changed over time in both conditions, although the mean differences and effect sizes were greater in the PBC condition. During IR, HR was 3.5% lower after PBC, and the same result was observed for oxygen uptake (∼4.9% lower) and ventilation (∼6.5% lower). The energy cost measured after cryotherapy was ∼9.0% lower than after passive recovery. Cryotherapy enhances recovery after a single strength training session, and during subsequent IR, it shows a reduction in cardiorespiratory and metabolic parameters. PBC may be useful for those athletes who compete or train more than once in the same day, to improve recovery between successive training sessions or competitions.

Predicting Lactate Threshold With Rate of Perceived Exertion in Young Competitive Male Swimmers

2021 ◽  
pp. 003151252110052
Author(s):  
Jhonny K. F. da Silva ◽  
Bruna B. Sotomaior ◽  
Carolina F. Carneiro ◽  
Patrick Rodrigues ◽  
Lee Wharton ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Test Protocol ◽  
Male Athletes ◽  
Rate Of Perceived Exertion ◽  
Significant Difference ◽  
Maximal Deviation ◽  
Competitive Swimmers

The purpose of this study was to verify the effectiveness of the rate of perceived exertion threshold (RPET) for predicting young competitive swimmers’ lactate threshold (LT) during incremental testing. We enrolled 13 male athletes ( M age = 16, SD = 0.6 years) in an incremental test protocol consisting of eight repetitions of a 100-meter crawl with 2-minute intervals between each repetition. We collected data for blood lactate concentration ([La]) and Borg scale rate of perceived exertion (RPE) at the end of each repetition. The results obtained were: M RPET = 4.98, SD = 1.12 arbitrary units (A.U.) and M lactate threshold = 4.24, SD = 1.12 mmol.L−1, with [La] and RPE identified by the maximal deviation (Dmax) method without a significant difference ( p > 0.05) and large correlations between DmaxLa and DmaxRPE at variables for time (r = 0.64), velocity (r = 0.67) and percentage of personal best time (PB) (r = 0.60). These results suggest that RPET is a good predictor of LT in young competitive swimmers.

Efficiency of anaerobic work

1978 ◽  
Vol 44 (4) ◽  
pp. 564-570 ◽  
Author(s):  
L. B. Gladden ◽  
H. G. Welch
Keyword(s):  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
O2 Uptake ◽  
Vo2 Max ◽  
External Work ◽  
Anaerobic Work ◽  
Steady Level ◽  
Submaximal Work ◽  
Aerobic And Anaerobic

This study was undertaken to compare the efficiency of aerobic and anaerobic work. Nine subjects worked at approximately 100% VO2 max for 2 min while inspiring gas mixtures with O2 fractions ranging from 0.13 to 0.21. Exercise O2 uptake, recovery O2 uptake, and blood lactate concentration were measured. Steady level O2 uptake was measured in normoxia at submaximal loads of about 30, 50, and 70% of VO2 max. Fast recovery O2 uptake did not change as PIO2 was varied. Exercise O2 uptake and blood lactate concentrations were linearly related to PIO2. The ratio of the slopes of these lines provided an empirical expression of the O2 equivalent of blood lactate. This ratio was constant, suggesting that it is not less efficient to use ATP synthesized anaerobically. Energy input from lactate was calculated using this factor. Efficiency decreased as power output increased even at the submaximal work rates. This may result from either 1) a decrease in muscle efficiency, 2) an increase in metabolism that is not directly related to the external work, or 3) some combination of 1 and 2.

scholarly journals La privación de sueño no afecta la resistencia aeróbica ni la concentración de lactato en sangre de jóvenes deportistas (Sleep deprivation does not affect aerobic resistance or blood lactate concentration of young athletes)

Retos ◽  
2018 ◽  
pp. 221-223
Author(s):  
Jorge Alberto Aburto Corona ◽  
Tatiana Miranda Núñez ◽  
Alicia Bárcenas Ugalde ◽  
Roberto Espinoza Gutiérrez ◽  
Emilio Manuel Arrayales Millán
Keyword(s):  
Sleep Deprivation ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Aerobic Performance ◽  
Control Group ◽  
Experimental Conditions ◽  
Male Athletes ◽  
Physical Test ◽  
Significant Difference

El objetivo de este estudio fue determinar si la resistencia aeróbica y la concentración de lactato en sangre, pueden ser influenciados por la privación parcial o total del sueño en un grupo de deportistas. Se reclutaron 13 deportistas masculinos (21.8 ± 2.9 años de edad) los cuales fueron sometidos a tres condiciones experimentales: dormir cuatro horas (D4H), no dormir (0H) y una condición contol de dormir ocho horas (D8H). No se encontraron diferencias estadísticamente significativas en la resistencia aeróbica (p=.845). De la misma manera, no se halló diferencia significativa en la concentración de lactato en sangre (p>.05). Estos resultados señalan que la privación parcial (dormir cuatro horas) o total (no dormir) del sueño, previo a una prueba física, no es un factor que influya en el rendimiento aeróbico ni en la concentración de lactato en sangre en comparación a la cantidad de horas de sueño recomendadas (dormir ocho horas).Abstract. The purpose of this study was to determinate if aerobic performance and blood lactate concentration are influenced by partial or total sleep deprivation. Thirteen male athletes (age: 21.8 ± 2.9 y.o) were randomly assigned to three experimental conditions: sleep four hours (D4H), no sleep (0H), and sleep eigth hours (D8H, control group). No significant difference was found in the aerobic performance (p=.845). Similarly, there was no sifnificant difference in blood lactate concentration (p>.05). This results suggest that partial (sleep four hours) or total (no sleep) sleep deprivation before a physical test are not a factor influencing aerobic performance or blood lactate concentration compared to the amount of recommended hours of sleep (sleep eight hours).

Cardiopulmonary adaptations to pneumonectomy in dogs. I. Maximal exercise performance

1992 ◽  
Vol 73 (1) ◽  
pp. 362-367 ◽  
Author(s):  
C. C. Hsia ◽  
L. F. Herazo ◽  
R. L. Johnson
Keyword(s):  
Stroke Volume ◽  
Exercise Performance ◽  
Sham Group ◽  
Maximal Exercise ◽  
Lactate Concentration ◽  
Left Lung ◽  
Blood Lactate Concentration ◽  
O2 Uptake ◽  
Group A ◽  
Exercise Induced

Maximal exercise performance was evaluated in four adult foxhounds after right pneumonectomy (removal of 58% of lung) and compared with that in seven sham-operated control dogs 6 mo after surgery. Maximal O2 uptake (ml O2.min-1.kg-1) was 142.9 +/- 1.9 in the sham group and 123.0 +/- 3.8 in the pneumonectomy group, a reduction of 14% (P less than 0.001). Maximal stroke volume (ml/kg) was 2.59 +/- 0.10 in the sham group and 1.99 +/- 0.05 in the pneumonectomy group, a reduction of 23% (P less than 0.005). Lung diffusing capacity (DL(CO)) (ml.min-1.Torr-1.kg-1) reached 2.27 +/- 0.08 in the combined lungs of the sham group and 1.67 +/- 0.07 in the remaining lung of the pneumonectomy group (P less than 0.001). In the pneumonectomy group, DL(CO) of the left lung was 76% greater than that in the left lung of controls. Blood lactate concentration and hematocrit were significantly higher at exercise in the pneumonectomy group. We conclude that, in dogs after resection of 58% of lung, O2 uptake, cardiac output, stroke volume, and DL(CO) at maximal exercise were restricted. However, the magnitude of overall impairment was surprisingly small, indicating a remarkable ability to compensate for the loss of one lung. This compensation was achieved through the recruitment of reserves in DL(CO) in the remaining lung, the development of exercise-induced polycythemia, and the maintenance of a relatively large stroke volume in the face of an increased pulmonary vascular resistance.

Effects of priming exercise on VO2 kinetics and O2 deficit at the onset of stepping and cycling

1989 ◽  
Vol 66 (5) ◽  
pp. 2023-2031 ◽  
Author(s):  
P. E. di Prampero ◽  
P. B. Mahler ◽  
D. Giezendanner ◽  
P. Cerretelli
Keyword(s):  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Work Load ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Double Exponential ◽  
Vo2 Kinetics ◽  
Male Subjects ◽  
O2 Deficit

Breath-by-breath O2 uptake (VO2) kinetics and increase of blood lactate concentration (delta Lab) were determined at the onset of square-wave stepping (S) or cycling (C) exercise on six male subjects during 1) transition from rest (R) to constant work load, 2) transition from lower to heavier work loads, wherein the baseline VO2 (VO2 s) was randomly chosen between 20 and 65% of the subjects' maximal O2 uptake (VO2 max), and 3) inverse transition from higher to lower work loads and/or to rest. VO2 differences between starting and arriving levels were 20–60% VO2 max. In C, the VO2 on-response became monotonically slower with increasing VO2 s, the half time (t1/2) increasing from approximately 22 s for VO2 s = R to approximately 63 s when VO2 s approximately equal to 50% VO2 max. In S, the fastest VO2 kinetics (t1/2 = 16 s) was attained from VO2 s = 15–30% VO2 max, the t1/2 being approximately 25 s when starting from R or from 50% VO2 max. The slower VO2 kinetics in C were associated with a much larger delta Lab. The VO2 kinetics in recovery were essentially the same in all cases and could be approximated by a double exponential with t1/2 of 21.3 +/- 6 and 93 +/- 45 s for the fast and slow components, respectively. It is concluded that the O2 deficit incurred is the sum of three terms: 1) O2 stores depletion, 2) O2 equivalent of early lactate production, and 3) O2 equivalent of phosphocreatine breakdown.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Are Young Swimmers Short and Middle Distances Energy Cost Sex-Specific?

2021 ◽  
Vol 12 ◽  
Author(s):  
Danilo A. Massini ◽  
Tiago A. F. Almeida ◽  
Camila M. T. Vasconcelos ◽  
Anderson G. Macedo ◽  
Mário A. C. Espada ◽  
...  
Keyword(s):  
Body Composition ◽  
Lean Mass ◽  
Energy Cost ◽  
Energy Demand ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Lower Limbs ◽  
Swimming Velocity ◽  
Front Crawl ◽  
Time Curve

This study assessed the energy cost in swimming (C) during short and middle distances to analyze the sex-specific responses of C during supramaximal velocity and whether body composition account to the expected differences. Twenty-six swimmers (13 men and 13 women: 16.7 ± 1.9 vs. 15.5 ± 2.8 years old and 70.8 ± 10.6 vs. 55.9 ± 7.0 kg of weight) performed maximal front crawl swimming trials in 50, 100, and 200 m. The oxygen uptake (V˙O2) was analyzed along with the tests (and post-exercise) through a portable gas analyser connected to a respiratory snorkel. Blood samples were collected before and after exercise (at the 1st, 3rd, 5th, and 7th min) to determine blood lactate concentration [La–]. The lean mass of the trunk (LMTrunk), upper limb (LMUL), and lower limb (LMLL) was assessed using dual X-ray energy absorptiometry. Anaerobic energy demand was calculated from the phosphagen and glycolytic components, with the first corresponding to the fast component of the V˙O2 bi-exponential recovery phase and the second from the 2.72 ml × kg–1 equivalent for each 1.0 mmol × L–1 [La–] variation above the baseline value. The aerobic demand was obtained from the integral value of the V˙O2 vs. swimming time curve. The C was estimated by the rate between total energy releasing (in Joules) and swimming velocity. The sex effect on C for each swimming trial was verified by the two-way ANOVA (Bonferroni post hoc test) and the relationships between LMTrunk, LMUL, and LMLL to C were tested by Pearson coefficient. The C was higher for men than women in 50 (1.8 ± 0.3 vs. 1.3 ± 0.3 kJ × m–1), 100 (1.4 ± 0.1 vs. 1.0 ± 0.2 kJ × m–1), and 200 m (1.0 ± 0.2 vs. 0.8 ± 0.1 kJ × m–1) with p < 0.01 for all comparisons. In addition, C differed between distances for each sex (p < 0.01). The regional LMTrunk (26.5 ± 3.6 vs. 20.1 ± 2.6 kg), LMUL (6.8 ± 1.0 vs. 4.3 ± 0.8 kg), and LMLL (20.4 ± 2.6 vs. 13.6 ± 2.5 kg) for men vs. women were significantly correlated to C in 50 (R2adj = 0.73), 100 (R2adj = 0.61), and 200 m (R2adj = 0.60, p < 0.01). Therefore, the increase in C with distance is higher for men than women and is determined by the lean mass in trunk and upper and lower limbs independent of the differences in body composition between sexes.

Acute hormonal responses to two different fatiguing heavy-resistance protocols in male athletes

1993 ◽  
Vol 74 (2) ◽  
pp. 882-887 ◽  
Author(s):  
K. Hakkinen ◽  
A. Pakarinen
Keyword(s):  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Serum Testosterone ◽  
Free Testosterone ◽  
Male Athletes ◽  
Hormonal Responses ◽  
Extensor Muscles ◽  
Acute Hormonal Responses ◽  
Heavy Resistance Exercise ◽  
Serum Gh

To examine endogenous hormonal responses to heavy-resistance exercise, ten male strength athletes performed two fatiguing but different types of sessions on separate days. In session A the loads for the leg extensor muscles in the squat-lift exercise were maximal so that the subjects performed 20 sets at 1 repetition maximum (RM) (20 x 1 RM x 100%), whereas during session B the loads were submaximal (70%) but the subjects performed each of the 10 sets until the RM (i.e., 10 repetitions/set or 10 x 10 x 70%). The recovery time between the sets was always 3 min. A decrease of 10.3 +/- 4.7% (P < 0.001) occurred in the squat-lift in 1 RM during session A, whereas session B led to a decrease of 24.6 +/- 18.9% (P < 0.001) in 10 RM. Increases in the concentrations of serum total and free testosterone (P < 0.05 and 0.05, respectively), cortisol (P < 0.001), and growth hormone (GH, P < 0.001) were observed during session B, whereas the corresponding changes during session A were statistically insignificant except for the relatively slight increase (P < 0.01) in serum GH level. The significant (P < 0.001) increase in blood lactate concentration during the two sessions correlated significantly (P < 0.01) with the increase in serum GH concentration. The morning values of serum testosterone and free testosterone were significantly (P < 0.05–0.001) lowered on the 1st and 2nd rest days after the sessions.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxygen debt in submaximal and supramaximal exercise in children at high and low altitude

1986 ◽  
Vol 60 (1) ◽  
pp. 209-215 ◽  
Author(s):  
N. Fellmann ◽  
M. Bedu ◽  
H. Spielvogel ◽  
G. Falgairette ◽  
E. Van Praagh ◽  
...  
Keyword(s):  
Lactate Concentration ◽  
Anaerobic Capacity ◽  
Blood Lactate Concentration ◽  
Work Load ◽  
Maximal Heart Rate ◽  
O2 Uptake ◽  
Bicycle Exercise ◽  
Linear Relationships ◽  
Low Altitude ◽  
O2 Debt

The effect of high altitude (HA) on O2 debt and blood lactate concentration [( L]) was examined in 10- to 13-yr-old children who exhibited the same level of physical fitness. Fifty-one children acclimatized to HA (3,700 m) were compared with 40 children living at low altitude (LA, 330 m) during submaximal (20–95% maximal aerobic power, MAP), maximal and supramaximal (115% MAP) bicycle exercise. Results showed that 1) maximal O2 uptake (VO2max) and maximal heart rate were significantly (P less than 0.001) lower at HA than at LA by 15% and 11 beats X min-1, respectively; 2) for a given absolute work load, O2 debt was higher at HA than at LA, and the slopes of the linear relationships between O2 debt and O2 uptake were significantly higher at HA; 3) when related to percent of VO2max, O2 debts in HA and LA were similar; for 115% MAP maximal O2 debt and [L] were not significantly different (maximal O2 debt, 45.7 +/- 2.7 and 45.9 +/- 3.8 ml X kg-1; [L], 6.0 +/- 0.3 and 6.7 +/- 0.5 mM); and 4) linear relationships between maximal O2 debt and [L] were the same at HA and LA. This suggests that HA did not modify the anaerobic capacity in children.

Sign in / Sign up

Export Citation Format

Share Document