Search Results

You are looking at 1 - 10 of 12 items for :

  • "oxygen kinetics" x
Clear All
Restricted access

Thiago Oliveira Borges, Ben Dascombe, Nicola Bullock and Aaron J. Coutts

This study aimed to profile the physiological characteristics of junior sprint kayak athletes (n = 21, VO2max 4.1 ± 0.7 L/min, training experience 2.7 ± 1.2 y) and to establish the relationship between physiological variables (VO2max, VO2 kinetics, muscle-oxygen kinetics, paddling efficiency) and sprint kayak performance. VO2max, power at VO2max, power:weight ratio, paddling efficiency, VO2 at lactate threshold, and whole-body and muscle oxygen kinetics were determined on a kayak ergometer in the laboratory. Separately, on-water time trials (TT) were completed over 200 m and 1000 m. Large to nearly perfect (−.5 to −.9) inverse relationships were found between the physiological variables and on-water TT performance across both distances. Paddling efficiency and lactate threshold shared moderate to very large correlations (−.4 to −.7) with 200- and 1000-m performance. In addition, trivial to large correlations (−.11 to −.5) were observed between muscle-oxygenation parameters, muscle and whole-body oxygen kinetics, and performance. Multiple regression showed that 88% of the unadjusted variance for the 200-m TT performance was explained by VO2max, peripheral muscle deoxygenation, and maximal aerobic power (P < .001), whereas 85% of the unadjusted variance in 1000-m TT performance was explained by VO2max and deoxyhemoglobin (P < .001). The current findings show that well-trained junior sprint kayak athletes possess a high level of relative aerobic fitness and highlight the importance of the peripheral muscle metabolism for sprint kayak performance, particularly in 200-m races, where finalists and nonfinalists are separated by very small margins. Such data highlight the relative aerobic-fitness variables that can be used as benchmarks for talent-identification programs or monitoring longitudinal athlete development. However, such approaches need further investigation.

Restricted access

Sarah J. Willis, Jules Gellaerts, Benoît Mariani, Patrick Basset, Fabio Borrani and Grégoire P. Millet

training and for being extremely short (∼10 s) in world-class distance runners. 14 These V ˙ O 2 kinetics parameters are unknown in elite ultratrail runners. Therefore, the aim of the present study was to investigate the oxygen cost, oxygen kinetics, and kinematics of level and uphill running in elite

Restricted access

Kyle M.A. Thompson, Alanna K. Whinton, Shane Ferth, Lawrence L. Spriet and Jamie F. Burr

Ischemic preconditioning (IPC) was initially developed to protect the myocardium from ischemia through altered cardiocyte metabolism. Because of the observed effects on metabolism and oxygen kinetics, IPC gained interest as a potential ergogenic aid in sports. Limited research evaluating the effects of IPC on maximal short-duration activities has been performed, and of the existing literature, mixed outcomes resulting from intrasubject variation may have clouded the efficacy of this technique for enhancing sprint performance. Therefore, the current study employed a randomized repeated-measures crossover design with IPC, placebo (SHAM), and control conditions while using sprint-trained athletes (N = 18) to determine the effect of IPC (3 × 5-min occlusions, with 5-min reperfusion), concluding 15 min prior to maximal 10-s and 20-m sprinting. A visual analog scale was used in conjunction with the sprint trials to evaluate any possible placebo effect on performance. Despite a “significantly beneficial” perception of the IPC treatment compared with the SHAM trials (P < .001), no changes in sprint performance were observed after either the IPC or SHAM condition over 10 m (IPC Δ  < 0.01 [0.02] s, SHAM Δ  < 0.01 [0.02] s) or 20 m (IPC Δ = −0.01 [0.03] s, SHAM Δ < 0.01 [0.03] s) compared with control. Thus, an IPC protocol does not improve 10- or 20-m sprint performance in sprint-trained athletes.

Restricted access

Luc Mertens, Tony Reybrouck, Benedicte Eyskens, Wim Daenen and Marc Gewillig

Peak oxygen consumption and anaerobic threshold are both decreased in patients with a Fontan-type circulation. This study wanted to evaluate oxygen uptake kinetics at the onset and at the end of of a steady-state low-level exercise. The delay in cardiorespiratory response was evaluated by calculating the oxygen deficit at the onset of exercise and the recovery half-time at the end. Twelve patients with Fontan circulation (aged 11.4 − SD 5.1 year; 5.2 − 1.9 year after surgery) and 26 normal controls of comparable age (11.3 − 2.2 year) were submitted to a constant-load exercise test of six minutes on a treadmill (speed 5 km/h, inclination 4%). Gas exchange was measured using a breath-by-breath technique. The normalized oxygen deficit was calculated by subtracting the oxygen uptake (VO2) values measured at the onset of exercise from the steady-state VO2 obtained at the end of exercise. These differences were cumulated and expressed as a percentage of the cumulated oxygen cost for the 6 min exercise test. The half-time recovery time was defined as the time to reach 50% of the end exercise VO2 value. The normalized oxygen deficit was significantly higher in Fontan-patients compared to the control group (10.2 − 4.6% vs. 6.1 − 1.3%; p < .001). Also the recovery half-time was significantly higher in the patient group compared to the control group (74.2 − 25.6 s vs. 51.2 − 10.8 s; p < .05). A blunted heart rate response was present in the patients during the first two minutes of exercise, indicating that a slowed cardiac output response could explain the decreased oxygen kinetics in Fontan-patients.

Restricted access

Pedro L. Valenzuela, Guillermo Sánchez-Martínez, Elaia Torrontegi, Javier Vázquez-Carrión, Manuela González, Zigor Montalvo and Grégoire P. Millet

. Perceptual Response The overall rating of perceived exertion (overall RPE) and the fatigue perceived locally on the legs (legs RPE) were determined using Borg CR-10 scale at the end of the training session. Oxygen Kinetics Pulse oxygen saturation (SpO 2 ) was assessed with a finger oximeter (Dimed, Vizcaya

Restricted access

David Giles, Joel B. Chidley, Nicola Taylor, Ollie Torr, Josh Hadley, Tom Randall and Simon Fryer

) Both arms’ finger flexors were tested together; pilot work identified that the greater amount of weight required for a single-arm test increased the resistance of the pulleys used to adjust the load by an unacceptable amount. Given the difference in finger flexor oxygen kinetics between the dominant

Restricted access

James R. Broatch, David J. Bishop and Shona Halson

shorter rest periods will rely more heavily on aerobic adenosine triphosphate provision, thereby implicating blood flow as an important determinant of RSE performance. This study aims to assess the benefits of lower limb compression garments on blood flow, oxygen kinetics, and exercise performance during

Restricted access

Nicola Giovanelli, Lea Biasutti, Desy Salvadego, Hailu K. Alemayehu, Bruno Grassi and Stefano Lazzer

. PubMed ID: 21364944 doi:10.1371/journal.pone.0017059 21364944 10.1371/journal.pone.0017059 22. Kasikcioglu E , Arslan A , Topcu B , et al . Cardiac fatigue and oxygen kinetics after prolonged exercise . Int J Cardiol . 2006 ; 108 ( 2 ): 286 – 288 . PubMed ID: 16517287 doi:10.1016/j

Restricted access

Øyvind Sandbakk, Guro Strøm Solli and Hans-Christer Holmberg

Indeed, the fractional utilization of VO 2 max is influenced to various degrees by numerous discipline-related factors such as the maximal lactate steady state, oxygen kinetics, and the ability to produce power with a given technique. The extent to which these factors, individually or in combination

Restricted access

Patrick P.J.M. Schoenmakers, Florentina J. Hettinga and Kate E. Reed

A , Zafeiridis A , Toubekis A , Spassis A , Tokmakidis SP . The effects of recovery duration during high-intensity interval exercise on time spent at high rates of oxygen consumption, oxygen kinetics and blood lactate . J Strength Cond Res . 2018 ; 32 ( 8 ): 2183 – 2189 . doi:10