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Respiratory exchange ratio in athletes

Yvonne Kilian, Florian Engel, Patrick Wahl, Silvia Achtzehn, Billy Sperlich, Joachim Mester
PURPOSE: The aim of the present study was to compare the effects of high-intensity interval training (HIIT) vs high-volume training (HVT) on salivary stress markers [cortisol (sC), testosterone (sT), alpha-amylase (sAA)], metabolic and cardiorespiratory response in young athletes. METHODS: Twelve young male cyclists (14 ± 1 years; 57.9 ± 9.4 mL min(-1) kg(-1) peak oxygen uptake) performed one session of HIIT (4 × 4 min intervals at 90-95 % peak power output separated by 3 min of active rest) and one session of HVT (90 min constant load at 60 % peak power output)...
December 2016: European Journal of Applied Physiology
Matthew A Wyon, Nick Allen, Ross Cloak, Sarah Beck, Paul Davies, Frances Clarke
An athlete's cardiorespiratory profile, maximal aerobic capacity, and anaerobic threshold is affected by training regimen and competition demands. The present study aimed to ascertain whether there are company rank differences in maximal aerobic capacity and anaerobic threshold in elite classical ballet dancers. Seventy-four volunteers (M 34, F 40) were recruited from two full-time professional classical ballet companies. All participants completed a continuous incremental treadmill protocol with a 1-km/hr speed increase at the end of each 1-min stage until termination criteria had been achieved (e...
September 2016: Medical Problems of Performing Artists
Matthew Zimmerman, Grant Landers, Karen E Wallman
This study examined the effects of pre-cooling via ice ingestion on female cycling performance in hot, humid conditions. Ten female endurance athletes, mean age (28±6 y), height (167.6±6.5 cm) and body-mass (68.0±11.5 kg) participated in the study. Participants completed an 800 kJ cycle time-trial in hot, humid conditions (34.9±0.3°C, 49.8±3.5% RH). This was preceded by the consumption of 7 g·kg(-1) of crushed ice (ICE) or water (CON). There was no difference in performance time (CON 3851±449 s; ICE 3767±465 s), oxygen consumption (CON 41...
August 24, 2016: International Journal of Sport Nutrition and Exercise Metabolism
Tiffany L Morton, Kornelia Galior, Cody McGrath, Xin Wu, Gunes Uzer, Guniz Bas Uzer, Buer Sen, Zhihui Xie, David Tyson, Janet Rubin, Maya Styner
Muscle lipid increases with high-fat feeding and diabetes. In trained athletes, increased muscle lipid is not associated with insulin resistance, a phenomenon known as the athlete's paradox. To understand if exercise altered the phenotype of muscle lipid, female C57BL/6 mice fed CTL or high-fat diet (HFD for 6 or 18 weeks) were further divided into sedentary or exercising groups (CTL-E or HFD-E) with voluntary access to running wheels for the last 6 weeks of experiments, running 6 h/night. Diet did not affect running time or distance...
2016: Frontiers in Endocrinology
Claudio Perret, Martin Wenger, Christof A Leicht, Victoria L Goosey-Tolfrey
PURPOSE: In wheelchair racing, respiratory muscles of the rib cage are concomitantly involved in non-ventilatory functions during wheelchair propulsion. However, the relationship between locomotor-respiratory coupling (LRC: the ratio between push and breathing frequency), respiratory parameters and work efficiency is unknown. Therefore, the aim of the present study was to investigate the LRC in wheelchair racers over different race distances. METHODS: Eight trained and experienced wheelchair racers completed three time-trials over the distances of 400, 800, and 5000 m on a training roller in randomized order...
2016: Frontiers in Physiology
Raul De Souza Silveira, Anja Carlsohn, Georg Langen, Frank Mayer, Friederike Scharhag-Rosenberger
BACKGROUND: Exercising at intensities where fat oxidation rates are high has been shown to induce metabolic benefits in recreational and health-oriented sportsmen. The exercise intensity (Fatpeak) eliciting peak fat oxidation rates is therefore of particular interest when aiming to prescribe exercise for the purpose of fat oxidation and related metabolic effects. Although running and walking are feasible and popular among the target population, no reliable protocols are available to assess Fatpeak as well as its actual velocity (VPFO) during treadmill ergometry...
2016: Journal of the International Society of Sports Nutrition
Hanna Karen Moreira Antunes, Geovana Silva Fogaça Leite, Kil Sun Lee, Amaury Tavares Barreto, Ronaldo Vagner Thomatieli Dos Santos, Helton de Sá Souza, Sergio Tufik, Marco Tulio de Mello
The aim of this study was to identify the possible association between biochemical markers of exercise addiction and affective parameters in a sample of athletes during 2weeks of withdrawal exercise. Eighteen male runners were distributed into a control group (n=10) composed of runners without exercise addiction symptoms and an exercise addiction group (n=8) composed of runners with exercise addiction symptoms. The volunteers performed a baseline evaluation that included affective questionnaires, blood samples, body composition and an aerobic test performed at ventilatory threshold I...
March 15, 2016: Physiology & Behavior
Adam J Berrones, Stephanie P Kurti, Korey M Kilsdonk, Delonyx J Cortez, Flavia F Melo, Michael Whitehurst
Berrones, AJ, Kurti, SP, Kilsdonk, KM, Cortez, DJ, Melo, FF, and Whitehurst, M. Barefoot running reduces the submaximal oxygen cost in female distance runners. J Strength Cond Res 30(8): 2348-2353, 2016-Being a competitive distance runner is, in part, attributable to a high V[Combining Dot Above]O2max. However, running economy (RE) is a more robust indicator of distance running performance among endurance athletes of similar V[Combining Dot Above]O2max levels. The purpose of this study was to examine the influence of unshod (barefoot) vs...
August 2016: Journal of Strength and Conditioning Research
Carolin Stangier, Thomas Abel, Julia Mierau, Wildor Hollmann, Heiko K Strüder
This study was designed to investigate the intensity profile during an inline speed skating marathon road race. A highly-trained male athlete (20 y, 73.4 kg, 178 cm, V̇O2 peak: 60.8 mL·kg-1·min-1) participated in a marathon road race. Oxygen uptake (V̇O2), respiratory exchange ratio (RER), heart rate (HR) and speed were measured using a portable gas analysis system with a HR monitor and GPS-Sensor integrated. The athlete´s peak V̇O2, HR and speed at ventilatory thresholds were assessed during an incremental field test (22 km·h-1, increase 2 km·h-1 every 5 min) one week before the race...
September 2016: Journal of Sports Medicine and Physical Fitness
Carolin Stangier, Thomas Abel, Clemens Hesse, Stephanie Claen, Julia Mierau, Wildor Hollmann, Heiko K Strüder
Winter weather conditions restrict regular sport-specific endurance training in inline speed skating. As a result, this study was designed to compare the effects of cycling and running training programs on inline speed skaters' endurance performance. Sixteen (8 men, 8 women) high-level athletes (mean ± SD 24 ± 8 years) were randomly assigned to 1 of 2 groups (running and cycling). Both groups trained twice a week for 8 weeks, one group on a treadmill and the other on a cycle ergometer. Training intensity and duration was individually calculated (maximal fat oxidation: ∼52% of V[Combining Dot Above]O2peak: 500 kcal per session)...
2016: Journal of Strength and Conditioning Research
J Sinclair, R Mcgrath, O Brook, P J Taylor, S Dillon
Running economy is a reflection of the amount of inspired oxygen required to maintain a given velocity and is considered a determining factor for running performance. Athletic footwear has been advocated as a mechanism by which running economy can be enhanced. New commercially available footwear has been developed in order to increase energy return, although their efficacy has not been investigated. This study aimed to examine the effects of energy return footwear on running economy in relation to conventional running shoes...
2016: Journal of Sports Sciences
José Luis Maté-Muñoz, Raúl Domínguez, Manuel Barba, Antonio J Monroy, Bárbara Rodríguez, Pedro Ruiz-Solano, Manuel V Garnacho-Castaño
This study was designed to identify the blood lactate threshold (LT2) for the half squat (HS) and to examine cardiorespiratory and metabolic variables during a HS test performed at a work intensity corresponding to the LT2. Twenty-four healthy men completed 3 test sessions. In the first, their one-repetition maximum (1RM) was determined for the HS. In the second session, a resistance HS incremental-load test was performed to determine LT2. Finally, in the third session, subjects performed a constant-load HS exercise at the load corresponding to the LT2 (21 sets of 15 repetitions with 1 min of rest between sets)...
September 2015: Journal of Sports Science & Medicine
Mahdi Sareban, David Zügel, Karsten Koehler, Paul Hartveg, Martina Zügel, Uwe Schumann, Jürgen Michael Steinacker, Gunnar Treff
The ingestion of exogenous carbohydrates (CHO) during prolonged endurance exercise, such as long-distance triathlon, is considered beneficial with regard to performance. However, little is known about whether this performance benefit differs among different forms of CHO administration. To this end, the purpose of our study was to determine the impact of CHO ingestion from a semisolid source (GEL) on measures of performance and gastrointestinal (GI) comfort compared with CHO ingestion from a liquid source (LIQ)...
April 2016: International Journal of Sport Nutrition and Exercise Metabolism
Efthymios Iliopoulos, Nikiforos Galanis, Michael Iosifidis, Andreas Zafeiridis, Pericles Papadopoulos, Michael Potoupnis, Nikolaos Geladas, Ioannis S Vrabas, John Kirkos
PURPOSE: Patients with ACL injury requiring surgical treatment (non-copers) demonstrate altered neuromuscular control and gait pattern compared with those returning to their pre-injury activities without surgery (copers). Pathological gait pattern may increase the energy cost of walking. We compared the energy cost of flat, uphill, and downhill walking between ACL-deficient and healthy individuals and between "copers" and "non-copers". METHODS: Nineteen young males with unilateral ACL injury were allocated into "copers" and "non-copers" according to their ability to return to pre-injury activity without ACL reconstruction...
August 1, 2015: Knee Surgery, Sports Traumatology, Arthroscopy: Official Journal of the ESSKA
David K P McNeill, John R Kline, Hendrick D de Heer, J Richard Coast
Lower body positive pressure (LBPP), or 'anti-gravity' treadmills® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS) on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min·mile(-1) pace (3...
June 2015: Journal of Sports Science & Medicine
Gabriela Fischer, Pedro Figueiredo, Luca P Ardigò
PURPOSE: To investigate physiological performance determinants of the partial laps and an overall 22-km handbiking (HB) time trial in athletes with high paraplegia. METHODS: Seven male HB athletes with spinal cord injury (lesion levels thoracic 2-8) performed a laboratory maximal incremental test under cardiorespiratory-mechanical monitoring including respiratory-exchange ratio (RER), oxygen uptake (VO2), and mechanical power output (PO). Individual first and second ventilatory thresholds (VO 2VT1 and VO 2VT2), VO 2peak, and PO peak were posteriorly identified...
November 2015: International Journal of Sports Physiology and Performance
Michael Ofner, Manfred Wonisch, Mario Frei, Gerhard Tschakert, Wolfgang Domej, Julia M Kröpfl, Peter Hofmann
The goal of this study is to evaluate the response of physiological variables to acute normobaric hypoxia compared to normoxia and its influence on the lactate turn point determination according to the three-phase model of energy supply (Phase I: metabolically balanced at muscular level; Phase II: metabolically balanced at systemic level; Phase III: not metabolically balanced) during maximal incremental exercise. Ten physically active (VO2max 3.9 [0.49] l·min(-1)), healthy men (mean age [SD]: 25.3 [4.6] yrs...
December 2014: Journal of Sports Science & Medicine
C Martyn Beaven, Sarah J Willis, Christian J Cook, Hans-Christer Holmberg
Lower body eccentric exercise is well known to elicit high levels of muscular force with relatively low cardiovascular and metabolic strain. As a result, eccentric exercise has been successfully utilised as an adaptive stressor to improve lower body muscle function in populations ranging from the frail and debilitated, to highly-trained individuals. Here we investigate the metabolic, cardiorespiratory, and energy costs of upper body eccentric exercise in a healthy population. Seven men and seven women performed 4-min efforts of eccentric (ECC) or concentric (CON) arm cycling on a novel arm ergometer at workloads corresponding to 40, 60, and 80% of their peak workload as assessed in an incremental concentric trial...
2014: PloS One
Andrew T Scott, Thomas O'Leary, Simon Walker, Rachel Owen
PURPOSE: To investigate the effect of ingesting a caffeinated carbohydrate gel (CC) 10 minutes prior on 2000-m rowing performance compared with a carbohydrate-only placebo gel (CP). METHODS: A counterbalanced, single-blind, crossover study design was employed (N=13). All participants completed 1 familiarization trial followed by 2 experimental rowing time trials. The experimental trials were performed 10 min after ingesting CP (21.6 g of carbohydrate, 0 mg caffeine) or CC (21...
May 2015: International Journal of Sports Physiology and Performance
D Vicente-Campous, C Barbado, M J Nuñez, J L Chicharro
AIM: The purpose of the present study was to determine whether running speed determined in a lactate minimum test (lactate minimum intensity, LMI) during a treadmill incremental exercise performed just after submaximal cycling corresponds to the speed of a respiratory exchange ratio of 1.00 (RER-1) and, by extension, to the maximal lactate steady state (MLSS) previously obtained in a standard incremental exercise test. METHODS: Eighteen moderately trained triathletes (15 men, 3 women) underwent two exercise sessions 72 h apart in random order: 1) a standard incremental treadmill test to identify the speed corresponding to RER-1, and 2) a submaximal exercise test on a bicycle-ergometer to obtain the LT (lactate threshold) followed by the incremental portion of the lactate minimum test on the treadmill...
December 2014: Journal of Sports Medicine and Physical Fitness
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