Biomedical subjects

D D Pascoe

Publications and source records attributed to D D Pascoe.

At least 19 recordsLinked to original sources

PubMed2005

Hyperthermia increases exercise-induced oxidative stress.

The purpose of this investigation was to examine oxidative markers after exercise in a hyperthermic environment (35 degrees C, 70 % RH) (Hot) versus a neutral environment (25 degrees C, 40 % RH) (Con). Hyperthermia may exacerbate oxidative stress by uncoupling the mitochondrial respiratory chain or by inhibiting antioxidant defense mechanisms, but this has not been assessed in vivo. Six male subjects performed low-intensity exercise (50 % VO(2max)) on a treadmill in Hot until a core temperature of 39.5 degrees C was reached, and for an equivalent time in Con. Blood samples were drawn before and immediately after exercise and at 8 min and 15 min following exercise. Samples were analyzed for F2 isoprostanes (FIP), lipid hydroperoxides (LPO), and lactate. A 2 x 4 repeated measures ANOVA was used to test for treatment, time, and interaction effects for FIP, LPO, and lactate. Differences in VO(2) were tested with Student's t-test. Significance was set at p < 0.05. Oxygen consumption was not significantly different between Hot and Con. The pattern of change of FIP and lactate in Hot was significant versus exercise in Con. LPO was significantly elevated over time in both Hot and Con, but the pattern of change was not significantly different. Ending core temperatures and heart rates were significantly elevated in Hot versus Con. These data indicate that hyperthermia increases oxidative stress and selectively affects specific lipid markers, independent of oxygen consumption.

Adolescent↗

PubMed2001

Evaluation of book backpack load during walking.

This investigation evaluated accumulated mean and peak impact forces per stride and per metre associated with two book backpack loads and two cadences during single and double support phases of walking. Thirty college participants randomly performed three trials while either walking a self-selected cadence or fixed cadence without (empty pack) or with a load (15% body mass) carried in a bookbag. The fixed cadence (55.5 steps/min) was regulated by a metronome. A computerized Kistler force platform system (phase-locked timing device) recorded (200 Hz) three-dimensional reaction forces, impulses, and time in single and double support phases. A Panasonic video camera AG-450 was set perpendicular to the plane of walking motion to film (60 Hz) the walking pattern from which stride length and selected kinematic data were determined. Repeated measure ANOVA (p<0.05) determined differences of loads and cadences in walking. Accumulated force was evaluated as impulses per stride and impulses per metre (stress index). When carrying the 15% load, there was a decrease in speed, a decrease in single support time (SST), and an increase in double support time (DST). The impulses per stride significantly increased in DST, and significantly decrease in SST. When impulses were analysed per metre, the stress index signficantly increased in DST, but not during SST. These differences in SST may be important when load stress is applied to the single support leg/foot in any given distance of walking. While stride analysis identifies accumulative forces resulting from varying stride lengths, the stress index provides a standardized measure per metre of the accumulative forces that negate the variances of individual stride lengths, and the index measure can easily represent data for any given distance traversed.

Adult↗

PubMed2001

Comparison of the BOD POD with the four-compartment model in adult females.

PURPOSE: This study was designed to compare the accuracy and bias in estimates of total body density (Db) by hydrostatic weighing (HW) and the BOD POD, and percent body fat (%fat) by the BOD POD with the four-compartment model (4C model) in 42 adult females. Furthermore, the role of the aqueous and mineral fractions in the estimation of body fat by the BOD POD was examined. METHODS: Total body water was determined by isotope dilution ((2)H(2)0) and bone mineral was determined by dual-energy x-ray absorptiometry. Db and %fat were determined by the BOD POD and HW. The 4C model of Baumgartner was used as the criterion measure of body fat. RESULTS: HW Db (1.0352 g x cm(-3)) was not statistically different (P = 0.35) from BOD POD Db (1.0349 g x cm(-3)). The regression between Db by HW and the BOD POD significantly deviated from the line of identity (Db by HW = 0.90 x Db by BOD POD + 0.099; R(2) = 0.94). BOD POD %fat (28.8%) was significantly lower (P < 0.01) than %fat by the 4C model (30.6%). The regression between %fat by the 4C model and the BOD POD significantly deviated from the line of identity (%fat by 4C model = 0.88 x %fat by BOD POD + 5.41%; R(2) = 0.92). BOD POD Db and %fat showed no bias across the range of fatness. Only the aqueous fraction of the fat-free mass (FFM) had a significant correlation with the difference in %fat between the 4C model and the BOD POD. CONCLUSION: These data indicate that the BOD POD underpredicted body fat as compared with the 4C model, and the aqueous fraction of the FFM had a significant effect on estimates of %fat by the BOD POD.

Absorptiometry, Photon↗

PubMed2001

Force patterns of heel strike and toe off on different heel heights in normal walking.

This study investigated the changes of force patterns of the heel strike and toe off phases at different heel heights during normal walking. Ten healthy female college students wore running shoes, flat leather shoes and high heeled shoes while walking on a Kistler force platform at their self-comfortable paces. It was found that the high heeled shoes and the leather shoes generated significantly greater vertical impact forces and anterior-posterior forces in the toe off phase than those in the heel strike phase. Accumulated impulses did not show significant increase while the heel heights increased and total support time while wearing the high heeled shoes was significantly longer than while wearing the running shoes.

Adult↗

PubMed1998

Effect of induced alkalosis on exhaustive leg press performance.

PURPOSE: Fifteen males were studied before, during, and in recovery from exhaustive resistance exercise 105 min after ingesting 0.3 g.kg-1 of either a placebo (white flour) or sodium bicarbonate (NaHCO3). METHODS: The exercise consisted of five maximal sets on a leg press machine, The load was adjusted to maintain the number of repetitions per set for each subject at approximately 12 repetitions. A significant (P < 0.05) increase in pH (7.40 to 7.47), oxygenated base excess (OxyBE) (-1.3 to 4.0 mEq.L-1), and bicarbonate concentration ([HCO3-]) (22.8 to 27.4 mM) was achieved before exercise with the ingestion of NaHCO3. RESULTS: The exercise protocol produced significant changes in acid base status consistent with metabolic acidosis for both trials (pH sets 1-5: placebo, 7.4 to 7.26; NaHCO3, 7.47 to 7.33), (OxyBE sets 1-5: placebo, -1.3 to -12.3 mEq.L-1; NaHCO3, 4.0 to -6.9 mEq.L-1) and ([HCO3-] sets 1-5: placebo, 22.9 to 14.0 mM; NaHCO3, 27.4 to 17.6 mM). After every set; pH, OxyBE, and [HCO3-] were significantly higher in the NaHCO3 trial. Blood lactate concentration ([La-]) significantly increased throughout exercise for both trials ([La-] sets 1-5: placebo, 4.6 to 11.3 mM; NaHCO3, 4.8 to 13.4 mM). After sets 4 and 5, blood [La-] was significantly higher in the NaHCO3 trial. Bicarbonate ingestion did not improve performance (total repetitions: NaHCO3 = 59 +/- 3; placebo = 60 +/- 2). CONCLUSIONS: This may be a result of a lower demand on the whole body metabolic system in comparison with that for other modes of exercise in which ergogenic effects have been found.

Adult↗

PubMed1998

Lactate distribution in the blood during steady-state exercise.

PURPOSE: The purpose of this investigation was to examine the plasma to red blood cell (RBC) lactate concentration ([La]) gradient and RBC:plasma [La] ratio during 30 min of steady-state cycle ergometer exercise at work rates below lactate threshold ( LT. Blood samples were taken from a heated forearm vein, immediately cooled to 4 degrees C in a dry-ice ethanol slurry, and centrifuged at 4 degrees C to separate plasma and RBCs. RESULTS: During >LT, plasma [La] rose to 8.8+/-1.1 mM after 10 min and remained above 6 mM. RBC [La] (4.9+/-0.7 mM) was significantly lower than plasma [La] at 10 min and remained lower throughout exercise. As a result, there was a sizable [La] gradient (approximately 3.5 mM) from plasma to RBC during most of >LT. In LT, the ratio of RBC [La]:plasma [La] was the same for both (0.58+/-0.02) and not significantly different from rest. CONCLUSIONS: These results refuted our hypothesis that the RBC:plasma [La] ratio would decrease at the onset of >LT exercise because of muscle lactate release exceeding the ability of RBCs to take up the lactate. Instead, there appears to be an equilibrium between plasma [La] and RBC [La] in arterialized venous blood from a resting muscle group as evidenced by the constant RBC [La]:plasma [La] ratio.

Adult↗

PubMed1997

Influence of carrying book bags on gait cycle and posture of youths.

The purpose of this investigation was to determine the impact of different methods of carrying book bags on static posture and gait kinematics of youths aged 11-13 years. Surveys identified group descriptive characteristics of subjects and book bags. Ten subjects representing the best composite of the mean characteristics of this population were filmed for both static posture and dynamic conditions of one stride length. Subjects participated in four conditions: without bag (WO), one-strap backpack (1BP), two-strap backpack (2BP), and one-strap athletic bag (ATH). Lateral spinal deviation was not significantly different between 2BP and WO. However, differences (+/-SE) were observed between 1BP (8.5 +/- 0.7 degrees) and ATH (8.3 +/- 2.4 degrees) as compared with WO (1.9 +/- 0.5 degrees). Shoulder elevation from a horizontal position showed no difference between WO and 2BP. Without bag (2.0 +/- 0.9 degrees) was different from 1BP (17.6 +/- 1.8 degrees) and ATH (15.6 +/- 2.1 degrees). 1BP was also different from 2BP (3.4 +/- 1.1 degrees). Bag carrying significantly decreased stride length (1.59 +/- 0.04 m) and increased stride frequency (57.36 +/- 1.6 cycles/min) compared to WO (1.72 +/- 0.06 m; 54.64 +/- 1.2 cycles/min, respectively), thereby reducing the support phase of the gait. One-strap bags (1BP, ATH) promoted lateral spinal bending and shoulder elevation, while the two-strap backpack significantly reduced these book bag carrying stresses. ATH promoted greater angular motion of the head and trunk as compared to backpack book bags. Carrying a backpack (1BP, 2BP) promoted significant forward lean of head and trunk compared to ATH or WO. In conclusion, the daily physical stresses associated with carrying book bags on one shoulder (1BP, ATH) significantly alters the posture and gait of youth.

Adolescent↗

PubMed1997

Lactate distribution in the blood during progressive exercise.

The purpose of this study was to examine the effect of increment durations of 1-min and 4-min during progressive incremental exercise tests on: 1) the distribution of lactate between plasma and red blood cells (RBCs), and 2) lactate threshold (LT) detection via three conventional methods using whole blood lactate concentration ([La]) or plasma [La]. Eight males (age, 22.5 +/- 0.6 yr: height, 170.6 +/- 2.3 cm, weight, 76.0 +/- 3.1 kg, and VO2peak, 42.8 +/- 2.0 mL.kg-1.min-1) performed two progressive load tests to volitional fatigue on a cycle ergometer. Work rate was increased 30 W at 1-min or 4-min intervals. All data were normalized to individual LT work rates. For both protocols, whole blood [La], plasma [La], RBC [La], and [La] gradient increased significantly (P < 0.05) after exercise intensity exceeded LT. However, the RBC:plasma [La] ratio remained at the resting value throughout the progressive exercise tests. The increase in [La] gradient after LT, with no change in the RBC:plasma lactate ratio, suggests that given an incremental work rate increase of 30 W, 1 min is adequate for equilibration of lactate between the plasma and RBCs. Also, under the conditions of this investigation, neither blood fraction analyzed nor exercise protocol had any effect on estimations of LT (in terms of VO2) by the Visual and Log-Log methods. However, LT determined by a fixed [La] of 2 mM may underestimate LT when plasma samples are used.

Adult↗

PubMed1996

Muscle glycogen resynthesis after short term, high intensity exercise and resistance exercise.

Typical rates of muscle glycogen resynthesis after short term, high intensity exercise (15.1 to 33.6 mmol/kg/h) are much higher than glycogen resynthesis rates following prolonged exercise (approximately 2 mmol/kg/h), even when optimal amounts of oral carbohydrate are supplied (approximately mmol/kg/h). Several factors differ during post-exercise recovery from short term, high intensity exercise compared with prolonged exercise. The extremely fast rate of muscle glycogen resynthesis following short term, high intensity exercise may originate from these differences. First, peak blood glucose levels range from 6.6 to 8.9 mmol/L during recovery from short term, high intensity exercise. This is markedly higher than the blood glucose values of 2 to 3.4 mmol/L after prolonged exercise. In response to this elevation in plasma glucose levels, insulin levels increase to approximately 60 microU/ml, a 2-fold increase over resting values. Both glucose and insulin regulate glycogen synthase activity, and higher levels of them improve muscle glycogen synthesis. Secondly, high intensity exercise produces high levels of glycolytic intermediates in muscle, as well as high lactate levels ([La]) in muscle and blood. Finally, fast-twitch glycolytic muscle fibres are more heavily used in short term, high intensity exercise. This promotes greater glycogen depletion in the fast-twitch fibres, which have a higher level of glycogen synthase activity than slow-twitch fibres. While the exact contribution of each of these factors is unknown, they may act in combination to stimulate rapid muscle glycogen resynthesis rates. Muscle glycogen resynthesis rates following resistance exercise (1.3 to 11.1 mmol/kg/h) are slower than the rates observed after short term, high intensity exercise. This may be caused by slightly lower muscle and blood [La] after resistance exercise. In addition, a greater eccentric component in the resistance exercise may cause some interference with glycogen resynthesis.

Animals↗

PubMed1994

Clothing and exercise. I: Biophysics of heat transfer between the individual, clothing and environment.

Despite large environmental variations, the human body maintains a tightly regulated core temperature. Effective thermoregulation must balance the interaction between skin surface, clothing and ambient air. Indices of thermal stress (wet bulb globe temperature, heat stress index, maximum evaporation rate, required evaporative rate and wind chill) provide valuable information concerning the heat exchange between the individual and the environment, and serve as protective guidelines while working in environmental extremes. The role of clothing, as an interactive barrier, greatly affects thermal balance. Clothing is varied according to prevailing environmental conditions, metabolic heat production, gender and age differences, fabric thermal properties, garment design and intended use. Models (static, dynamic and human) have investigated the biophysical transfer of heat between the skin surface area, clothing and ambient air. Additionally, the role of metabolic heat production during exercise can greatly influence tolerance to thermal stress during a variety of environmental conditions.

Adolescent↗

PubMed1994

Clothing and exercise. II. Influence of clothing during exercise/work in environmental extremes.

Thermoregulatory studies often investigate thermal responses without considering the influences of clothing. These studies have expanded our understanding of basic human responses to various environmental conditions. However, human thermoregulation is variable and modified by heat transfer interactions between skin surface area, clothing and environment. Much of the original work on the influence of clothing on work performance was the result of ergonomic concerns. Currently, the importance of clothing and the influence of new clothing technology aimed at minimising thermal stress has spawned a new interest. For hot climates, new fabrics have been developed with improved wicking properties to keep the wearer cooler and drier, and to enhance heat transfer from the body while providing greater comfort. In contrast, the challenge of cold environments requires a different approach to clothing, which tries to minimise the free movement of air and water along the skin surface of the body. The materials used should also be able to absorb radiant heat from the environment and be nonconductive. In a cold climate, the wearer needs to balance the need for a clothing barrier for warmth with the potential for accumulating too much heat as the result of metabolic heat production from exercise. To counteract this potential problem, it is suggested that cold-weather clothing be worn in layers that can be removed during exercise and replaced during less active periods. Protective clothing for firefighters, hazardous waste workers and astronauts, and athletic protective gear, have specialised design requirements which may be influenced by considerations, for example, of environmental conditions, garment weight, the need for durability, impact forces.

Body Temperature Regulation↗

PubMed1993

Glycogen resynthesis in skeletal muscle following resistive exercise.

The purpose of this investigation was to determine the influence of post-exercise carbohydrate (CHO) intake on the rate of muscle glycogen resynthesis after high intensity weight resistance exercise in subjects not currently weight training. In a cross-over design, eight male subjects performed sets (mean = 8.8) of six single leg knee extensions at 70% of one repetition max until 50% of full knee extension was no longer possible. Total force application was equated between trials using a strain gauge interfaced to a computer. The subjects exercised in the fasted state. Post-exercise feedings were administered at 0 and 1 h consisting of either a 23% CHO solution (1.5 g.kg-1) or an equal volume of water (H2O). Total force production, preexercise muscle glycogen content, and degree of depletion (-40.6 and -44.3 mmol.kg-1 wet weight) were not significantly different between H2O and CHO trials. As anticipated during the initial 2-h recovery, the CHO trial had a significantly greater rate of muscle glycogen resynthesis as compared with the H2O trial. The muscle glycogen content was restored to 91% and 75% of preexercise levels when water and CHO were provided after 6 h, respectively.

Adult↗

PubMed1992

The effects of a carbonated carbohydrate drink on gastric emptying, gastrointestinal distress, and exercise performance.

To determine the effect of a carbonated carbohydrate (CHO) drink on gastric function and exercise performance, eight male cyclists completed four 120-min bouts of cycling. Each bout consisted of a 105-min ride at 70% VO2max followed by a 15-min self-paced performance ride. During each trial, one of four test solutions was ingested: carbonated CHO (C-10%), noncarbonated CHO (NC-10%), carbonated non-CHO (C), and noncarbonated non-CHO (NC). Following the performance ride, the subjects had their stomach contents removed by aspiration. There were no significant differences in gastric emptying (GE) except for Trial C-10%, which averaged 13.3% less than NC. However, there was no difference in the perception of gastrointestinal comfort between this trial and any other. Average power output during the performance ride was not significantly different between carbonated and noncarbonated trials, or between CHO-fed and no-CHO trials; however, the subjects worked at a greater intensity when fed CHO. Finally, acid base status did not change when a carbonated drink was ingested. This indicates that adding carbonation to a sport drink does not significantly alter gastric function, the perception of GI comfort, or exercise performance.

Adult↗

PubMed1991

Muscle glycogenolysis during differing intensities of weight-resistance exercise.

Skeletal muscle glycogen metabolism was investigated in eight male subjects during and after six sets of 70% one repetition maximum (1 RM, I-70) and 35% 1 RM (I-35) intensity weight-resistance leg extension exercise. Total force application to the machine lever arm was determined via a strain gauge and computer interfaced system and was equated between trials. Compared with the I-70 trial, the I-35 trial was characterized by almost double the repetitions (13 +/- 1 vs. 6 +/- 0) and half the peak concentric torque for each repetition (12.4 +/- 0.5 vs. 24.2 +/- 1.0 Nm). After the sixth set, muscle glycogen degradation was similar between I-70 and I-35 trials (47.0 +/- 6.6 and 46.6 +/- 6.0 mmol/kg wet wt, respectively), as was muscle lactate accumulation (13.8 +/- 0.7 and 16.7 +/- 4.2 mmol/kg wet wt, respectively). After 2 h of passive recovery without caloric intake, muscle glycogen increased by 22.2 +/- 6.8 and 14.2 +/- 2.5 mmol/kg wet wt in the I-70 and I-35 trials, respectively. Optical absorbance measurement of periodic acid-Schiff-stained muscle sections after the 2 h of recovery revealed larger absorbance increases in fast-twitch than in slow-twitch fibers (0.119 +/- 0.024 and 0.055 +/- 0.024, P = 0.02). Data indicated that when external work was constant, the absolute amount of muscle glycogenolysis was the same regardless of the intensity of resistance exercise. Nevertheless the rate of glycogenolysis during the I-70 trial was approximately double that of the I-35 trial.

Adult↗

PubMed1991

Influence of muscle glycogen depletion on the rate of resynthesis.

In an effort to determine what effect the degree of muscle glycogen depletion has on the rate of resynthesis, six male cyclists completed an exercise protocol that involved both one- and two-legged cycling. One leg completed 30 min of single-leg cycling, ten one-min sprints, and 30 min cycling with both legs. This resulted in a large degree of depletion (LD). The contralateral leg completed only 30 min of double-leg cycling and experienced a small amount of depletion (SD). Following the exercise, the subjects rested quietly for 6 h and were fed a 24% carbohydrate (CHO) solution every 20 min in order to achieve a CHO intake of 0.7 g.kg-1.h-1. Biopsies taken from the vastus lateralis muscle immediately after exercise revealed that the glycogen content of the LD leg decreased 93.9 (+/- 11.6) mmol.kg-1 w.w., whereas the SD leg used 49.3 (+/- 5.7) mmol.kg-1 w.w. (P less than 0.01). Subsequent biopsies taken at 2 and 6 h of recovery demonstrated that the rate of muscle glycogen resynthesis was significantly greater in the LD leg, averaging 8.8 (+/- 2.4) mmol.kg-1.h1 w.w, while the SD leg restored glycogen at a rate of 3.0 (+/- 1.0) mmol.kg-1.h-1 w.w. (P less than 0.05). Glycogen synthase activity, expressed as its activity ratio (I/D), was also greater (P less than 0.01) in the LD leg both immediately after exercise (0.45 +/- 0.05 vs 0.24 +/- 0.04) and at 2 h of recovery (0.54 +/- 0.06 vs 0.27 +/- 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Effects of warm-up on muscle glycogenolysis during intense exercise.

This study investigated the effects of preliminary exercise (warm-up) on glycogen degradation and energy metabolism during intense cycle ergometer exercise. After determination of VO2max, six male subjects were randomly assigned to perform warm-up (WU) and no warm-up (NWU) trials incorporating a 2 min standardized sprint ride (SR) at 120% of the power output attained at VO2max (POmax). Muscle biopsies and temperature (Tm) recordings were obtained from the vastus lateralis muscle. Tm was elevated above the resting level prior to the SR during the WU trial (37.7 +/- 0.1 vs 35.4 +/- 0.4 degrees C; P less than 0.05) and remained higher than the NWU trial after the SR (38.6 +/- 0.2 vs 37.1 +/- 0.4 degrees C; P less than 0.05). Similar trends existed for rectal temperature (Tr). The increases in Tm and Tr during the SR were both greater in the NWU trial (P less than 0.05). Muscle glycogen degradation was similar for the WU and NWU trials (30.8 +/- 3.7 vs 25.6 +/- 3.7 mmol.kg-1, respectively). When blood and muscle lactate concentrations after the SR were expressed relative to values before the SR, the WU trial resulted in a lower accumulation of blood lactate (6.5 +/- 0.9 vs 10.7 +/- 0.8 mEq.l-1; P less than 0.01) and muscle lactate (20.1 +/- 0.1 vs 23.4 +/- 2.2 mEq.kg-1 wet wt.; P less than 0.05). Furthermore, oxygen consumption during the 1st min of the SR was higher in the WU trial (2.3 +/- 0.2 vs 1.9 +/- 0.2 l.min-1; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Effects of warm-up on blood gases, lactate and acid-base status during sprint swimming.

A standardized 200-m front crawl sprint swim (SpS) was used to evaluate the effects of warm-up on pH, blood gases, and the concentrations of lactate ([La-]) and bicarbonate ([HCO3-]) in arterialized and venous blood. Eight trained male swimmers performed two randomly assigned 200-m front crawl swims at previously determined intensities corresponding to 120% VO2max. One swim was preceded by a warm-up (WU trial) which consisted of a 400-m front crawl swim (82% VO2max), 400-m flutter kicking (45% VO2max), and 4 x 50-m front crawl sprints (111% VO2max). The second was performed without warm-up (NWU trial). Blood was sampled from a hyperemized earlobe and an antecubital vein before the warm-up, 9 min after the warm-up (1 min before the swim), immediately following the SpS, and at 2, 5, 10, and 20 min after the SpS. The warm-up exercise resulted in a higher pre-SpS [La-] in arterialized blood (3.1 +/- 0.4 and 1.7 +/- 0.4 mmol x l-1, p less than 0.05), a higher hydrogen ion concentration ([H+]) in venous blood (45.9 +/- 0.9 and 42.2 +/- 0.8 nmol x l-1, p less than 0.001), and a lower arterialized blood [HCO3-] (25.1 +/- 0.9 and 22.2 +/- 0.8 mmol x l-1, p less than 0.05). The SpS was accompanied with higher heart rates during the WU trial (178 +/- 3 and 169 +/- 3 bpm; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

Blood lactate threshold differences between arterialized and venous blood.

The purpose of this study was to investigate the differences between lactate thresholds determined from venous and arterialized blood. Seven endurance-trained college males performed an incremental bicycle ergometer exercise test until exhaustion. At the end of each 3 min stage, blood was sampled simultaneously from a hyperemized ear-lobe and an antecubital vein for the measurement of blood lactate (La-). Two-minute rest intervals separated each stage. Arterialized blood La-concentrations ([La-]) were significantly higher than venous blood at 350 W (14.5 and 9.7 mmol.l-1), maximal exercise (15.5 and 11.39 mmol.l-1), and throughout recovery. Arterialized [La-] was significantly higher than venous blood at the onset of blood La- accumulation (OBLA) (4.0 and 2.8 +/- 0.1 mmol.l-1), the individual anaerobic threshold (IAT) (3.4 +/- 0.3 and 2.1 +/- 0.1 mmol.l-1), and the ventilatory threshold (VT) (4.7 +/- 0.9 and 3.2 +/- 0.6 mmol.l-1). No significant differences were found between either La-threshold for arterialized or venous blood. The oxygen consumption (VO2) at OBLA was significantly lower when determined from arterialized blood La (2.3 +/- 0.2 and 2.8 +/- 0.2 l.min-1). No significant differences existed between the LT, OBLA, and IAT threshold-VO2 determinations from arterialized blood; however, significant differences were found between IAT-OBLA (2.1 +/- 0.2 and 2.8 +/- 0.2 l.min-1) and LT (2.2 +/- 0.2 l.min-1)-OBLA from venous blood. These results indicate that differences between venous and arterialized blood [La-] need to be considered when comparing different anaerobic threshold determinations.

Adult↗