Energy Cost of Running in Well-Trained Athletes: Toward Slope-Dependent Factors

Author(s):  
Marcel Lemire ◽  
Romain Remetter ◽  
Thomas J. Hureau ◽  
Bernard Geny ◽  
Evelyne Lonsdorfer ◽  
...  

Purpose: This study aimed to determine the contribution of metabolic, cardiopulmonary, neuromuscular, and biomechanical factors to the energy cost (ECR) of graded running in well-trained runners. Methods: Eight men who were well-trained trail runners (age: 29 [10] y, mean [SD]; maximum oxygen consumption: 68.0 [6.4] mL·min−1·kg−1) completed maximal isometric evaluations of lower limb extensor muscles and 3 randomized trials on a treadmill to determine their metabolic and cardiovascular responses and running gait kinematics during downhill (DR: −15% slope), level (0%), and uphill running (UR: 15%) performed at similar O2 uptake (approximately 60% maximum oxygen consumption). Results: Despite similar O2 demand, ECR was lower in DR versus level running versus UR (2.5 [0.2] vs 3.6 [0.2] vs 7.9 [0.5] J·kg−1·m−1, respectively; all P < .001). Energy cost of running was correlated between DR and level running conditions only (r2 = .63; P = .018). Importantly, while ECR was correlated with heart rate, cardiac output, and arteriovenous O2 difference in UR (all r2 > .50; P < .05), ECR was correlated with lower limb vertical stiffness, ground contact time, stride length, and step frequency in DR (all r2 > .58; P < .05). Lower limb isometric extension torques were not related to ECR whatever the slope. Conclusion: The determining physiological factors of ECR might be slope specific, mainly metabolic and cardiovascular in UR versus mainly neuromuscular and mechanical in DR. This possible slope specificity of ECR during incline running opens the way for the implementation of differentiated physiological evaluations and training strategies to optimize performance in well-trained trail runners.

1969 ◽  
Vol 47 (7) ◽  
pp. 603-610 ◽  
Author(s):  
Florent Depocas ◽  
Yves Minaire ◽  
Joseph Chatonnet

The rates of formation and oxidation of plasma lactic acid were measured in dogs, either resting quietly or running at 6 km/h on the level, by priming and continuous infusion with uniformly labelled 14C-lactic acid. During running at rates of oxygen consumption almost 5 times the resting value, corresponding to approximately 30% of the maximal effort, the rates of lactic acid formation and disposal were always greater than at rest and doubled on the average. Average plasma lactic acid concentrations during running were greater, equal, or lower than at rest in different dogs. The energy released by formation of the extra lactic acid from glucose during running represented, energetically, less than 0.5% of the extra energy cost of running. Seventy-four percent of the lactate formed was promptly converted to CO2, and about 12% of the respiratory carbon was derived from lactic acid in the running dogs. About 10% of the plasma glucose was derived from lactic acid during both rest and activity. At similar plasma lactate concentrations, running dogs had greater rates of formation of lactic acid than resting animals.


2021 ◽  
Vol 3 ◽  
Author(s):  
David Sundström ◽  
Markus Kurz ◽  
Glenn Björklund

The aim of this study was to investigate the influence of slope and speed on lower-limb kinematics and energy cost of running. Six well-trained runners (VO2max 72 ± 6 mL·kg−1·min−1) were recruited for the study and performed (1) VO2max and energy cost tests and (2) an experimental running protocol at two speeds, 12 km·h−1 and a speed corresponding to 80% of VO2max (V80, 15.8 ± 1.3 km·h−1) on three different slopes (0°, −5°, and −10°), totaling six 5-min workload conditions. The workload conditions were randomly ordered and performed continuously. The tests lasted 30 min in total. All testing was performed on a large treadmill (3 × 5 m) that offered control over both speed and slope. Three-dimensional kinematic data of the right lower limb were captured during the experimental running protocol using eight infrared cameras with a sampling frequency of 150 Hz. Running kinematics were calculated using a lower body model and inverse kinematics approach. The generic model contained three, one, and two degrees of freedom at the hip, knee, and ankle joints, respectively. Oxygen uptake was measured throughout the experimental protocol. Maximum hip extension and flexion during the stance phase increased due to higher speed (p &lt; 0.01 and p &lt; 0.01, respectively). Knee extension at the touchdown and maximal knee flexion in the stance phase both increased on steeper downhill slopes (both p &lt; 0.05). Ground contact time (GCT) decreased as the speed increased (p &lt; 0.01) but was unaffected by slope (p = 0.73). Runners modified their hip movement pattern in the sagittal plane in response to changes in speed, whereas they altered their knee movement pattern during the touchdown and stance phases in response to changes in slope. While energy cost of running was unaffected by speed alone (p = 0.379), a shift in energy cost was observed for different speeds as the downhill gradient increased (p &lt; 0.001). Energy cost was lower at V80 than 12 km·h−1 on a −5° slope but worse on a −10° slope. This indicates that higher speeds are more efficient on moderate downhill slopes (−5°), while lower speeds are more efficient on steeper downhill slopes (−10°).


2020 ◽  
Vol 12 (1) ◽  
pp. 225-232
Author(s):  
Paria Torkamandi ◽  
◽  
Ali Akbarnejad ◽  
Abbas Ali Gaeini ◽  
Ali Gharecheshmei Ghahremanloo ◽  
...  

Introduction: The current study aimed to evaluate the effects of different musical intensities on performance and cardiovascular responses after incremental exercise in male athletes. Materials and Methods: In this quasi-experimental study with a cross-over design, 15 male athletes were voluntarily selected. The study subjects performed Bruce protocol, along with listening to progressive music, slow music, and without music until exhaustion. Results: This study indicated that systolic and diastolic blood pressure, maximum oxygen consumption, maximum heart rate, and time to exhaustion insignificantly decreased while listening to slow music, compared to the no music (P=0.134, P=0.993, P=0.999, P=0.160, P=0.819, respectively). Furthermore, while listening to progressive music, compared to no music, the systolic and diastolic blood pressure, as well as maximum heart rate insignificantly increased (P=0.735, P=0.999, P=0.496, respectively); the maximum oxygen consumption and the time of exhaustion significantly increased in the study subjects (P=0.043, P=0.008 respectively). Moreover, while listening to progressive music, compared to slow music, the systolic blood pressure, maximum oxygen consumption, maximum heart rate, and the time of exhaustion significantly increased (P=0.004, P=0.009, P=0.002, P=0.001 respectively); however, diastolic blood pressure presented an insignificant decrease (P=0.253). Conclusion: The obtained findings revealed that listening to progressive music can affect physiological factors and performance during exercising. It increases the athlete’s motivation and postpones the time to exhaustion to continue exercising; however, listening to slow music creates a state of relaxation during exercise and reduces heart rate. As a result, individuals with hypertension can decline their blood pressure during endurance exercise by listening to soft music.


Author(s):  
Yu.G. Solonin ◽  
T.P. Loginova ◽  
I.O. Garnov ◽  
A.L. Markov ◽  
A.A. Chernykh ◽  
...  

The aim of the study is to examine the impact of training status on ski racers (Komi Republic) at rest and under bicycle ergometry evaluating their cardiorespiratory system parameters. Materials and Methods. The authors examined male ski racers with different training status: 22 first-rank sportsmen, 22 candidates for Master of Sports and 22 Masters of Sports. Athletes underwent bicycle ergometry loads up to refusal. Oxycon Pro system (Germany) was used. Then authors studied the complex of cardiorespiratory parameters, calculating maximum oxygen consumption and unit physiological cost. Results. At rest and under standard physical load (200 W) Masters of Sports demonstrate significantly increased training status among ski racers in such cardiorespiratory system parameters as heart rate, rate pressure product and oxygen pulse. Under standard physical load (200 W) statistically significant differences between first-rank sportsmen and candidates for Master of Sports are detected by heart rate, rate pressure product, respiration rate, respiratory minute volume and oxygen utilization coefficient. Such deviations indicate differences in training status. Under maximum load, the highest training status is found in Masters of Sports: bicycle ergometry load power and duration; unit pulse, pressor and cardiac cost, bulk and unit values of maximum oxygen consumption. Heart rate values, unit pulse and heart-vent cost indicate a high training status in candidates for Master of Sports under load up to refusal, if compared with first-rank sportsmen. Athletes’ organism under load up to refusal works more efficiently than under moderate load (200 W). The training status in ski racers (Komi Republic) is manifested in the saving cardiorespiratory system functions, both at rest and under standard bicycle ergometry, as well as in parameters of unit physiological cost under loads up to refusal and increased values of maximum oxygen consumption. Keywords: ski racers, Komi Republic, training status, bicycle ergometry loads, cardiorespiratory system, maximum oxygen consumption.


1999 ◽  
Vol 24 (1) ◽  
pp. 301-305
Author(s):  
V. Bunc ◽  
J. Horcic ◽  
J. Heller ◽  
J. Formánek

Author(s):  
Manuel Chavarrias ◽  
Santos Villafaina ◽  
Ana Myriam Lavín-Pérez ◽  
Jorge Carlos-Vivas ◽  
Eugenio Merellano-Navarro ◽  
...  

Background and objectives: Obesity or overweight is associated with many health risk factors and preventable mortality. Even people with normal weight and without history of obesity or overweight should avoid weight gain to reduce health risks factors. In this regard Latin aerobic dances involved in Zumba® practice make this modality motivating for people. Apart from weight loss and VO2peak benefits, Zumba practice is also interesting by the increase in adherence which can also avoid weight regain. The aim was to systematically review the scientific literature about the effects of any randomized intervention of Zumba® practice on total fat mass (%) and maximum oxygen consumption (VO2peak), besides establishing directions for the clinical practice. Evidence acquisition: Two systematic searches were conducted in two electronic databases following the PRISMA guidelines. The eligibility criteria were (a) outcomes: body mass or VO2peak data including mean and standard deviation (SD) before and after Zumba® intervention, (b) study design: randomized controlled trial (RCT) and (c) language: English. GRADE guidelines were used to assess the quality of evidence. A meta-analysis was performed to determine mean differences. Nine and four studies were selected for fat mass percentage and VO2peak in the systematic review, respectively. However, only eight studies for fat mass percentage and three for VO2peak could be included in the meta-analysis. Evidence synthesis: The overall standardized mean difference for fat mass was −0.25 with a 95% CI from −0.67 to 0.16 with a p-value of 0.69, with large heterogeneity. On the other hand, the overall effect size for VO2peak was 0.53 (95% CI from 0.04 to 1.02 with a p-value of 0.03) with large heterogeneity. Conclusions: Based on the evidence, we cannot conclude that Zumba® is effective at reducing body mass but it may improve VO2peak. However, the limited number of studies that met the inclusion criteria makes it too early to reach a definite conclusion, so more research is needed.


2010 ◽  
Vol 25 (2) ◽  
pp. 81-87 ◽  
Author(s):  
M. Buchheit ◽  
P.B. Laursen ◽  
F. Leblond ◽  
S. Ahmaidi

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