Non-oxidative Energy Supply Correlates with Lactate Transport and Removal in Trained Rowers.

This study aimed to test if the non-oxidative energy supply (estimated by the accumulated oxygen deficit) is associated with an index of muscle lactate accumulation during exercise, muscle monocarboxylate transporter content and the lactate removal ability during recovery in well-trained rowers. Seventeen rowers completed a 3-min all-out exercise on rowing ergometer to estimate the accumulated oxygen deficit. Blood lactate samples were collected during the subsequent passive recovery to assess individual blood lactate curves, which were fitted to the bi-exponential time function: La(t)= [La](0)+A·(1-e )+A·(1-e ), where the velocity constants γ and γ (min) denote the lactate exchange and removal abilities during recovery, respectively.

Factors of Rowing Ergometer Performance in High-Level Female Rowers.

The present study investigated morphological and physiological factors of rowing ergometer performance over 2000 m (P W) in 70 national and international level [27 lightweight (LW) and 43 heavyweight (HW)] female rowers. Maximal oxygen uptake (V̇O, L.min), maximal aerobic power (Pa, W), power output corresponding to 4 mmol.

Muscle MCT4 Content Is Correlated with the Lactate Removal Ability during Recovery Following All-Out Supramaximal Exercise in Highly-Trained Rowers.

The purpose of this study was to test if the lactate exchange (γ1) and removal (γ2) abilities during recovery following short all-out supramaximal exercise correlate with the muscle content of MCT1 and MCT4, the two isoforms of the monocarboxylate transporters family involved in lactate and H(+) co-transport in skeletal muscle. Eighteen lightweight rowers completed a 3-min all-out exercise on rowing ergometer. Blood lactate samples were collected during the subsequent passive recovery to assess an individual blood lactate curve (IBLC).

Factors affecting the energy cost of level running at submaximal speed.

Metabolic measurement is still the criterion for investigation of the efficiency of mechanical work and for analysis of endurance performance in running. Metabolic demand may be expressed either as the energy spent per unit distance (energy cost of running, C r) or as energy demand at a given running speed (running economy). Systematic studies showed a range of costs of about 20 % between runners.

A new approach to quantifying physical demand in rugby union.

The objective of the study was to describe an original approach to assessing individual workload during international rugby union competitions. The difference between positional groups and between the two halves was explored. Sixty-seven files from 30 French international rugby union players were assessed on a computerised player-tracking system (Amisco Pro(®), Sport Universal Process, Nice, France) during five international games.

Differences in lactate exchange and removal abilities between high-level African and Caucasian 400-m track runners.

The present study aimed to investigate (1) whether high-level 400-m track runners of different ethnic origin displayed divergent post-run blood lactate concentrations (p400m[La]) and (2) if this discrepancy was based on differences in lactate exchange and removal abilities. Twenty male African (n = 12) and Caucasian (n = 8) runners, paired in terms of personal record, performed (1) an all-out 400-m run to measure p400m[La] at 3, 5 and 7 min into recovery and (2) a 1-min 25.2 km h(-1) running (not maximal but standardized) exercise followed by 90-min passive recovery to determine individual blood lactate recovery curves (IBLRC).

Mechanical determinants of 100-m sprint running performance.

Sprint mechanics and field 100-m performances were tested in 13 subjects including 9 non-specialists, 3 French national-level sprinters and a world-class sprinter, to further study the mechanical factors associated with sprint performance. 6-s sprints performed on an instrumented treadmill allowed continuous recording of step kinematics, ground reaction forces (GRF), and belt velocity and computation of mechanical power output and linear force-velocity relationships. An index of the force application technique was computed as the slope of the linear relationship between the decrease in the ratio of horizontal-to-resultant GRF and the increase in velocity.

A virtual model of the bench press exercise.

The objective of this study was to design and validate a three degrees of freedom model in the sagittal plane for the bench press exercise. The mechanical model was based on rigid segments connected by revolute and prismatic pairs, which enabled a kinematic approach and global force estimation. The method requires only three simple measurements: (i) horizontal position of the hand (x(0)); (ii) vertical displacement of the barbell (Z) and (iii) elbow angle (theta).

Physiological correlates of performance. Case study of a world-class rower.

This report describes the changes in physiological capacity of a heavy-weight rower who obtained seven medals in World Championships and Olympic Games. The investigation was carried out over the last 6 years of the rower's international competition career in comparison with peer champions, and the following 4 years. Over the first period, maximal oxygen uptake (VO(2max)) remained above 6 l min(-1) which is an outstanding value.

Importance of upper-limb inertia in calculating concentric bench press force.

The purpose of this study was to investigate the influence of upper-limb inertia on the force-velocity relationship and maximal power during concentric bench press exercise. Reference peak force values (Fpeakp) measured with a force plate positioned below the bench were compared to those measured simultaneously with a kinematic device fixed on the barbell by taking (Fpeakt) or not taking (Fpeakb) upper-limb inertia into account. Thirteen men (27.

The leveling-off of oxygen uptake is related to blood lactate accumulation. Retrospective study of 94 elite rowers.

To assess whether the ability to demonstrate a plateau in oxygen consumption VO2 could be related to adaptation to exercise, the data obtained over a period of 10 years on 94 elite oarsmen who had participated in annual testing were re-evaluated. The test consisted in an incremental step protocol until volitional exhaustion. VO2, heart rate (HR), blood lactate ([La]b) and respiratory exchange ratio (RER) were measured at each step.

Influence of maxillary mouthguards on physiological parameters.

Introduction: The purpose of this study was to test the influence of two types of maxillary mouthguards (a self-adapted and a custom-made model: SA and CM, respectively) on various physiological parameters generally associated with performance in team sports.

Methods: Nineteen trained male subjects participating in team sports were tested. Visual reaction time, explosive power, ventilation at rest, and ventilation and oxygen consumption during submaximal and maximal exercise were measured in three randomized conditions: normal, with SA mouthguards, or with CM mouthguards.

The use of treadmill ergometers for extensive calculation of external work and leg stiffness during running.

Recently, new treadmill ergometers have been designed to measure the ground reaction forces during numerous successive steps. From ground reaction forces measured in track running, it has been shown to be possible to compute external mechanical work ( W(ext)) and leg stiffness ( k) of a bouncing spring-mass system. However, to the best of our knowledge, there is still no study reporting the inter-stride coefficient of variation (CoV) of W(ext) or k parameters calculated from many successive steps.

Influence of two pedalling rate conditions on mechanical output and physiological responses during all-out intermittent exercise.

The purpose of this study was to investigate the effect of two cycling velocities on power output and concomitant metabolic and cardiorespiratory responses to repeated all-out exercises. Mean power output (P(m)), total work ( W(tot)), total oxygen consumption (VO(2tot)) and blood lactate accumulation (delta[La](b)) were evaluated in 13 male subjects who performed two series of twelve 5-s bouts of sprint cycling. Recovery periods of 45-s were allowed between trials.