Effect of expertise on postmaximal long sprint blood metabolite responses

The aim of this study was to describe and compare the blood metabolic responses obtained after a single maximal exercise in elite and less-successful athletes and to investigate whether these responses are related to sprint performance. Eleven elite (ELI) and 14 regional (REG) long sprint runners performed a 300-m running test as fast as possible. Blood samples were taken at rest and at 4 minutes after exercise for measurements of blood lactate concentration [La] and acid-base status. The blood metabolic responses of ELI subjects compared to those of REG subjects for pH (7.07 ± 0.05 vs. 7.14 ± 1.5), sodium bicarbonate concentration ([HCO(3)(-)], 8.1 ± 1.5 vs. 9.8 ± 1.8 mmol·L(-1)), hemoglobin O(2) saturation (SaO(2)) (94.7 ± 1.8 vs. 96.2 ± 1.6%) were significantly lower (p < 0.05), and [La] was significantly higher in ELI (21.1 ± 2.9 vs. 19.1 ± 1.2 mmol·L(-1), p < 0.05). The 300-m performance (in % world record) was negatively correlated with pH (r = -0.55, p < 0.01), SaO2 (r = -0.64, p < 0.001), [HCO(3)(-)] (r = -0.40, p < 0.05), and positively correlated with [La] (r = 0.44, p < 0.05). In conclusion, for the same quantity of work, the best athletes are able to strongly alter their blood acid-base balance compared to underperforming runners, with larger acidosis and lactate accumulation. To obtain the pH limits with acute maximal exercise, coaches must have their athletes perform a distance run with duration of exercise superior to 35 seconds. The blood lactate accumulation values (mmol·L(-1)·s(-1)) recorded in this study indicate that the maximal glycolysis rate obtained in the literature from short sprint distances is maintained, but not increased, until 35 seconds of exercise.     

Creatine supplementation and multiple sprint running performance

The aim of this study was to examine the effects of short-term creatine monohydrate supplementation on multiple sprint running performance. Using a double-blind research design, 42 physically active men completed a series of 3 indoor multiple sprint running trials (15 x 30 m repeated at 35-second intervals). After the first 2 trials (familiarization and baseline), subjects were matched for fatigue score before being randomly assigned to 5 days of either creatine (4 x d(-1) x 5 g creatine monohydrate + 1 g maltodextrin) or placebo (4 x d(-1) x 6 g maltodextrin) supplementation. Sprint times were recorded via twin-beam photocells, and earlobe blood samples were drawn to evaluate posttest lactate concentrations. Relative to placebo, creatine supplementation resulted in a 0.7 kg increase in body mass (95% likely range: 0.02 to 1.3 kg) and a 0.4% reduction in body fat (95% likely range: -0.2 to 0.9%). There were no significant (p > 0.05) between-group differences in multiple sprint measures of fastest time, mean time, fatigue, or posttest blood lactate concentration. Despite widespread use as an ergogenic aid in sport, the results of this study suggest that creatine monohydrate supplementation conveys no benefit to multiple sprint running performance.     

Sodium bicarbonate ingestion improves performance in interval swimming

In an effort to determine the effects of bicarbonate (NaHCO3) ingestion on exercise performance, ten male college swimmers were studied during five different trials. Each trial consisted of five 91.4 m (100-yd) front crawl swims with a two-minute rest interval between each bout. The trials consisted of two NaHCO3 treatments, two placebo trials and one test with no-drink. One hour before the onset of swimming, the subjects were given 300 ml of citric acid flavored solution containing either 17 mmol of NaCl (placebo) or 2.9 mmol of NaHCO3.kg-1 body weight (experimental), or received no drink (no-drink). Performance times for each 91.4 m swim were recorded. Blood samples were obtained before and one hr after treatment, two min after warmup, and two min after the final 91.4 m sprint. Blood pH, lactate, standard bicarbonate (SBC) and base excess (BE) were measured. No differences were found for performance or the blood measurements between the placebo and no-drink trials. Bicarbonate feedings, on the other hand, produced a significant (P less than 0.05) improvement in performance on the fourth and fifth swimming sprints. Blood lactate, pH, SBC and BE were significantly higher (P less than 0.05) at post-exercise in NaHCO3 treatments. These data are in agreement with previous findings that during repeated bouts of exercise pre-exercise administration of NaHCO3 improves performance, possibly by facilitating the efflux of hydrogen ions from working muscles and thereby delaying the onset of fatigue.     

Effects of 4 weeks of creatine supplementation in junior swimmers on freestyle sprint and swim bench performance

To determine whether 4 weeks of oral creatine (Cr) supplementation could enhance single freestyle sprint and swim bench performance in experienced competitive junior swimmers, 10 young men and 10 young women (x age = 16.4 +/- 1.8 years) participated in a 27-day supplementation period and pre- and posttesting sessions. In session 1 (presupplementation testing), subjects swam one 50-m freestyle and then (after approximately 5 minutes of active recovery) one 100-m freestyle at maximum speed. Blood lactate was measured before and 1 minute after each swim trial. Forty-eight hours later, height, mass, and the sum of 6 skinfolds were recorded, and a Biokinetic Swim Bench total work output test (2 x 30-second trials, with a 10-minute passive recovery in between) was undertaken. After the pretests were completed, participants were divided into 2 groups (n = 10, Cr; and n = 10, placebo) by means of matched pairs on the basis of gender and 50-m swim times. A Cr loading phase of 20 g x d(-1) for 5 days was then instituted, followed by a maintenance phase of 5 g x d(-1) for 22 days. Postsupplementation testing replicated the presupplementation tests. Four weeks of Cr supplementation did not influence single sprint performance in the pool or body mass and composition. However, 30-second swim bench total work scores for trial 1 and trial 2 increased after Cr (p < 0.05) but not placebo ingestion. Postexercise blood lactate values were not different after supplementation for the 50- and 100-m sprint trials either within or between groups. It was concluded that 4 weeks of Cr supplementation did not significantly improve single sprint performance in competitive junior swimmers, but it did enhance swim bench test performance.     

The effect of creatine on treadmill running with high-intensity intervals

To determine whether creatine monohydrate supplementation would improve performance during a submaximal treadmill run interspersed with high-intensity intervals, 15 college soccer players (8 women, 7 men) received either creatine or a maltodextrin placebo at 0.3 g.kg body mass per day for 6 days. The speed of the treadmill was constant at 160.8 m.min, and every 2 minutes the grade was elevated to 15%. Each hill segment was 1 minute long. At the end of the 20-minute protocol, the treadmill was again elevated to 15% and held there until volitional exhaustion occurred. There was a significant treatment effect of creatine supplementation on body mass (p < 0.05) in the men; however, no significant differences were observed in the women (p > 0.05). There were no treatment effects (p > 0.05) on time to exhaustion, ratings of perceived exertion, or blood lactate concentration. There was a tendency for blood lactate levels to be lower after short-term creatine supplementation in the women, but this was not statistically significant. Based on these results, it appears that creatine supplementation does not improve performance in submaximal running interspersed with high-intensity intervals.     

Creatine supplementation does not reduce muscle damage or enhance recovery from resistance exercise

Previous studies have shown that creatine supplementation reduces muscle damage and inflammation following running but not following high-force, eccentric exercise. Although the mechanical strain placed on muscle fibers during high-force, eccentric exercise may be too overwhelming for creatine to exert any protective effect, creatine supplementation may protect skeletal muscle stressed by a resistance training challenge that is more hypoxic in nature. The purpose of this study was to examine the effects of short-term creatine supplementation on markers of muscle damage (i.e., strength, range of motion, muscle soreness, muscle serum protein activity, C-reactive protein) to determine whether creatine supplementation offers protective effects on skeletal muscle following a hypoxic resistance exercise test. Twenty-two healthy, weight-trained men (19-27 years) ingested either creatine or a placebo for 10 days. Following 5 days of supplementation, subjects performed a squat exercise protocol (5 sets of 15-20 repetitions at 50% of 1 repetition maximum [1RM]). Assessments of creatine kinase (CK) and lactate dehydrogenase activity, high-sensitivity C-reactive protein, maximal strength, range of motion (ROM), and muscle soreness (SOR) with movement and palpation were conducted pre-exercise and during a 5-day follow up. Following the exercise test, maximal strength and ROM decreased, whereas SOR and CK increased. Creatine and placebo-supplemented subjects experienced significant decreases in maximal strength (creatine: 13.4 kg, placebo: 17.5 kg) and ROM (creatine: 2.4 degrees , placebo: 3.0 degrees ) immediately postexercise, with no difference between groups. Following the exercise test, there were significant increases in SOR with movement and palpation (p < 0.05 at 24, 48, and 72 hours postexercise), and CK activity (p < 0.05 at 24 and 48 hours postexercise), with no differences between groups at any time. These data suggest that oral creatine supplementation does not reduce skeletal muscle damage or enhance recovery following a hypoxic resistance exercise challenge.     

Moderate potassium chloride supplementation in essential hypertension: is it additive to moderate sodium restriction?

Twenty patients with mild or moderate essential hypertension and not receiving any drug treatment, who had been moderately restricting their sodium intake to around 70 mmol(mEq) a day for at least one month and whose mean blood pressure was then 163/103 mm Hg, were entered into a double blind, randomised crossover study to compare one month''s treatment with slow release potassium chloride tablets (64 mmol potassium chloride a day) with one month''s treatment with a matching placebo. Mean (SEM) urinary sodium excretion on entry to the study was 68 (6.8) mmol/24 h. Mean urinary potassium excretion increased from 67 (6.9) mmol(mEq)/24 h with placebo to 117 (4.6) mmol/24 h with potassium chloride. Supine and standing systolic and diastolic blood pressures did not change significantly with potassium chloride supplementation when compared with pressures while receiving placebo or before randomisation. In patients who are able moderately to restrict their sodium intake doubling potassium as a chloride salt has little or no effect on blood pressure.     

Creatine serum is not as effective as creatine powder for improving cycle sprint performance in competitive male team-sport athletes

This study examined the effects of supplementation with either creatine monohydrate powder in solution (CP) or a widely available creatine serum (CS) on performance in a repeated maximal sprint cycling test (10 x 6 seconds, 24-second passive rest between sprints). Using a randomized, double-blind, crossover design, 11 competitive male athletes supplemented with creatine in 2 forms according to the manufacturer's recommendations on 2 separate occasions. The 2 supplementation protocols were (a) 20 g.day(-1) x 6 days of creatine powder in solution plus a placebo serum (CP) or (b) 5 ml.day(-1) x 6 days of creatine serum plus a placebo powder (CS). Subjects completed 2 familiarization trials before the 6-day supplementation period. A repeated maximal sprint cycling test was performed prior to and immediately postsupplementation. A 7-week washout period separated the 2 supplementation protocols. Subjects' total work (9.6%) and peak power (3.4%) in the cycle sprint improved significantly (p < 0.05) after loading with CP, but there was little change after loading with CS. The present data support previous research findings showing an ergogenic effect of CP supplementation but indicate that supplementation with CS does not affect sprint cycling performance. Although the levels of creatine in each formulation were not determined, a substantial conversion of creatine into creatinine has been reported in many formulations and may explain the present findings.     

Creatine supplementation increases muscle total creatine but not maximal intermittent exercise performance.

This study investigated creatine supplementation (CrS) effects on muscle total creatine (TCr), creatine phosphate (CrP), and intermittent sprinting performance by using a design incorporating the time course of the initial increase and subsequent washout period of muscle TCr. Two groups of seven volunteers ingested either creatine [Cr; 6 x (5 g Cr-H(2)O + 5 g dextrose)/day)] or a placebo (6 x 5 g dextrose/day) over 5 days. Five 10-s maximal cycle ergometer sprints with rest intervals of 180, 50, 20, and 20 s and a resting vastus lateralis biopsy were conducted before and 0, 2, and 4 wk after placebo or CrS. Resting muscle TCr, CrP, and Cr were unchanged after the placebo but were increased (P < 0.05) at 0 [by 22.9 +/- 4.2, 8.9 +/- 1.9, and 14.0 +/- 3.3 (SE) mmol/kg dry mass, respectively] and 2 but not 4 wk after CrS. An apparent placebo main effect of increased peak power and cumulative work was found after placebo and CrS, but no treatment (CrS) main effect was found on either variable. Thus, despite the rise and washout of muscle TCr and CrP, maximal intermittent sprinting performance was unchanged by CrS.     

The effect of three recovery protocols on blood lactate clearance after race-paced swimming

ABSTRACT: Lomax, M. The effect of three recovery protocols on blood lactate clearance after race-paced swimming. J Strength Cond Res 26(10): 2771-2776, 2012-The purpose of the present study was to assess the impact of 3 recovery protocols on blood lactate clearance after maximal intensity swimming. Thirty-three regional standard swimmers were tested throughout the course a year and were required to complete a race-paced 200-m swim in their main stroke or individual medley. After the race-paced swim, swimmers were assigned a self-paced continuous steady rate swim of 20 minutes (self-prescribed); a 20-minute coach-administered modified warm-up consisting of various swimming modes, intensities, and rest intervals (coach prescribed); or a 20-minute land-based recovery consisting of light-intensity walking, skipping, and stretching (land based). Blood lactate concentration was measured from the fingertip before and after the race-paced swim and after the recovery activity. The concentration of blood lactate was higher (p < 0.01) after race-paced swimming (range of 10.5-11.0 mmol·L) compared with baseline (range 1.3-1.4 mmol·L). However, there were no differences (p > 0.05) between the groups (recovery protocols) at these time points. Conversely, differences were observed between groups after the recovery activities (p < 0.01). Specifically, blood lactate concentration was higher after the land-based activity (3.7 ± 1.8 mmol·L) than either the self-prescribed (2.0 ± 1.2 mmol·L) or coach-prescribed (1.8 ± 0.9 mmol·L) swimming protocols. The results of the present study suggest that it does not matter whether a self-paced continuous steady rate swimming velocity or a swimming recovery consisting of various strokes, intensities, and rest intervals is adopted as a recovery activity. As both swimming recoveries removed more blood lactate than the land-based recovery, swimmers should therefore be advised to undertake a swimming-based recovery rather than a land-based recovery.     

Bicarbonate supplementation via lactate efflux improves anaerobic and cognitive performance in elite combat sport athletes

The aim of this study was the assessment of sodium bicarbonate supplementation (NaHCO₃ ^-) on anaerobic and cognitive performance, assuming ergogenic effect of HCO₃ by improving buffering capacity and greater lactate efflux, which may have indirect effect on circulating neurotrophin level (e.g BDNF, IGF-1) and memory. Sixteen well-trained judo athletes completed a randomized trial of either a NaHCO₃ ^- (EG) (5000 mg x 2/day/90 min before training)or placebo for 21 days (CG). Before and after treatment, athletes completed double Wingate test (Wt) protocol following which they performed perceived Working Memory test (pWM). Results suggested significant increase in Upper Limb Total Work (with p = 0.011), Mean Power (with p = 0.001), post exercise LA concentration (from 15.51 mmol/L to 18.10 mmol/L with p = 0.01) and HCO3_rest concentrations (from 27.37 mmol/l to 28.91 mmol/l with p = 0.001), when compared to baseline values in EG. The analysis showed statistically significant increase in values for IGF-1 (with p = 0.001) and decrease for cortisol and BDNF (with p = 0.001) in EG and CG, when pre and post exercise values were compared. We also revealed statistically significant decrease in values for display time after ingestion of HCO₃ between pre and post exercise (with p = 0.002) In conclusion, the lack of a substantial relationship between exerkines (IGF-1, BDNF) and memory in the present study might suggest that exercise induced lactate levels is dominant mechanism improving working memory in well-train athletes.     

Creatine supplementation influences substrate utilization at rest.

The influence of creatine supplementation on substrate utilization during rest was investigated using a double-blind crossover design. Ten active men participated in 12 wk of weight training and were given creatine and placebo (20 g/day for 4 days, then 2 g/day for 17 days) in two trials separated by a 4-wk washout. Body composition, substrate utilization, and strength were assessed after weeks 2, 5, 9, and 12. Maximal isometric contraction [1 repetition maximum (RM)] leg press increased significantly (P < 0.05) after both treatments, but 1-RM bench press was increased (33 +/- 8 kg, P < 0.05) only after creatine. Total body mass increased (1.6 +/- 0.5 kg, P < 0.05) after creatine but not after placebo. Significant (P < 0.05) increases in fat-free mass were found after creatine and placebo supplementation (1.9 +/- 0.8 and 2.2 +/- 0.7 kg, respectively). Fat mass did not change significantly with creatine but decreased after the placebo trial (-2.4 +/- 0.8 kg, P < 0.05). Carbohydrate oxidation was increased by creatine (8.9 +/- 4.0%, P < 0.05), whereas there was a trend for increased respiratory exchange ratio after creatine supplementation (0.03 +/- 0.01, P = 0.07). Changes in substrate oxidation may influence the inhibition of fat mass loss associated with creatine after weight training.     

Creatine monohydrate supplementation on body weight and percent body fat

Seventeen active males (age 22.9 +/- 4.9 year) participated in a study to examine the effects of creatine monohydrate supplementation on total body weight (TBW), percent body fat, body water content, and caloric intake. The TBW was measured in kilograms, percent body fat by hydrostatic weighing, body water content via bioelectrical impedance, and caloric intake by daily food log. Subjects were paired and assigned to a creatine or placebo group with a double-blind research design. Supplementation was given for 4 weeks (30 g a day for the initial 2 weeks and 15 g a day for the final 2 weeks). Subjects reported 2 days a week for supervised strength training of the lower extremity. Significant increases before and after the study were found in TBW (90.42 +/- 14.74 to 92.12 +/- 15.19 kg) and body water content (53.77 +/- 1.75 to 57.15 +/- 2.01 L) for the creatine group (p = 0.05). No significant changes were found in percent body fat or daily caloric intake in the creatine group. No significant changes were noted for the placebo group. These findings support previous research that creatine supplementation increases TBW. Mean percent body fat and caloric intake was not affected by creatine supplementation. Therefore weight gain in lieu of creatine supplementation may in part be due to water retention.     

Effects of chronic bicarbonate ingestion on the performance of high-intensity work

We have evaluated whether sodium bicarbonate, taken chronically (0.5 g x kg(-1) body mass) for a period of 5 days would improve the performance of eight subjects during 60 s of high-intensity exercise on an electrically braked cycle ergometer. The first test was performed prior to chronic supplementation (pre-ingestion) while the post-ingestion test took place 6 days later. A control test took place approximately 1 month after the cessation of all testing. Acid-base and metabolite data (n = 7) were measured from arterialised blood both pre- and post-exercise, as well as daily throughout the exercise period. The work completed by the subjects in the control and pre-ingestion test [21.1 (0.9) and 21.1 (0.9) MJ, respectively] was less than (P<0.05) that completed in the post-ingestion test [24.1 (0.9) MJ; F(2,21) = 3.4, P<0.05, power = 0.57]. Peak power was higher after the 5-day supplementation period (P<0.05). Ingestion of the sodium bicarbonate for a period of 5 days resulted in an increase in pH (F(5,36) = 12.5, P<0.0001, power = 1.0) over the 5-day period. The blood bicarbonate levels also rose during the trial (P<0.05) from a resting level of 22.8 (0.4) to 28.4 (1.1) mmol x l(-1) after 24 h of ingestion. In conclusion, the addition of sodium bicarbonate to a normal diet proved to be of ergogenic benefit in the performance of short-term, high-intensity work.     

Opposite actions of caffeine and creatine on muscle relaxation time in humans.

The effect of creatine and caffeine supplementation on muscle torque generation and relaxation was investigated in healthy male volunteers. Maximal torque (T(max)), contraction time (CT) from 0.25 to 0.75 of T(max), and relaxation time (RT) from 0.75 to 0.25 of T(max) were measured during an exercise test consisting of 30 intermittent contractions of musculus quadriceps (2 s stimulation, 2 s rest) that were induced by electrical stimulation. According to a double-blind randomized crossover design, subjects (n = 10) performed the exercise test before (pretest) and after (posttest) creatine supplementation (Cr, 4 x 5 g/day, 4 days), short-term caffeine intake (Caf, 5 mg x kg(-1) x day(-1), 3 days), creatine supplementation + short-term caffeine intake (Cr+Caf), acute caffeine intake (ACaf, 5 mg/kg) or placebo. Compared with placebo, Cr shortened RT by approximately 5% (P < 0.05). Conversely, Caf increased RT (+ approximately 10%, P < 0.05), in particular as RT increased because of fatigue. RT was not significantly changed by either Cr+Caf or ACaf. T(max) and CT were similar during all experimental conditions. Initial T(max) was approximately 20% of voluntary maximal isometric contraction force, which was not different between treatments. It is concluded that Caf intake (3 days) prolongs muscle RT and by this action overrides the shortening of RT due to creatine supplementation.     

Caffeine and sprinting performance: dose responses and efficacy

The aims of this study were to evaluate the effects of caffeine supplementation on sprint cycling performance and to determine if there was a dose-response effect. Using a randomized, double-blind, placebo-controlled design, 17 well-trained men (age: 24 ± 6 years, height: 1.82 ± 0.06 m, and body mass(bm): 82.2 ± 6.9 kg) completed 7 maximal 10-second sprint trials on an electromagnetically braked cycle ergometer. Apart from trial 1 (familiarization), all the trials involved subjects ingesting a gelatine capsule containing either caffeine or placebo (maltodextrin) 1 hour before each sprint. To examine dose-response effects, caffeine doses of 2, 4, 6, 8, and 10 mg·kg bm(-1) were used. There were no significant (p ≥ 0.05) differences in baseline measures of plasma caffeine concentration before each trial (grand mean: 0.14 ± 0.28 μg·ml(-1)). There was, however, a significant supplement × time interaction (p < 0.001), with larger caffeine doses producing higher postsupplementation plasma caffeine levels. In comparison with placebo, caffeine had no significant effect on peak power (p = 0.11), mean power (p = 0.55), or time to peak power (p = 0.17). There was also no significant effect of supplementation on pretrial blood lactate (p = 0.58), but there was a significant time effect (p = 0.001), with blood lactate reducing over the 50 minute postsupplementation rest period from 1.29 ± 0.36 to 1.06 ± 0.33 mmol·L(-1). The results of this study show that caffeine supplementation has no effect on short-duration sprint cycling performance, irrespective of the dosage used.     

Biochemical responses during recovery from maximal and submaximal swimming exercise

We set out to demonstrate whether changes in plasma volume, haematocrit and some important blood constituents occurred after swimming 100 m and 800 m, as well as monitoring the duration of these changes. We measured exercise-induced changes in concentration of plasma constituents in eight subjects, and determined the expected effects of haemoconcentration on these constituents. We also investigated the different biochemical responses occurring after maximal exercise (100 m), as compared to submaximal exercise (800 m). The haematocrit increased significantly after the 100 m swim and to a lesser extent after the 800-m swim, returning to basal levels within 30 min. The plasma volume decreased by 16% on completion of the 100 m and by 8% on completion of the 800 m. The blood lactate concentration increased 15-fold and 10-fold after the 100-m and 800-m swims respectively. The plasma potassium concentration increased significantly immediately on completion of the 100-m swim, then decreased significantly at 2 1/2 and 5 min post-exercise, returning to near-basal values at 30 min. The potassium concentration measured after the 800-m event did not differ significantly from basal levels, however the measured concentrations were significantly lower than the concentrations expected on the basis of haemoconcentration. The plasma sodium concentrations measured after both 100-m and 800-m swims were significantly increased. However, calculations correcting for haemoconcentration showed significant losses in total circulating sodium.     

Effect of creatine supplementation on intermittent sprint running performance in highly trained athletes

This study examined the impact of short-term (7-day), high-dose (0.35 g.kg(-1).d(-1)) oral creatine monohydrate supplementation (CrS) on single sprint running performance (40 m, <6 seconds) and on intermittent sprint performance in highly trained sprinters. Nine subjects completed the double-blind cross-over design with 2 supplementation periods (placebo and creatine) and a 7-week wash-out period. A test protocol consisting of 40-m sprint runs was performed, and running velocity was continuously recorded over the total distance. The maximal sprint performance, the relative degree of fatigue at the end of intermittent sprint exercise (6 x 40 m, 30-second rest interval), as well as the degree of recovery (120-second passive rest) remained unchanged following CrS. There were no significant changes related to CrS in absolute running velocity at any distance between start and finish (40 m). It was concluded that no ergogenic effect on single or repeated 40-m sprint times with varying rest periods was observed in highly trained athletes.     

Does creatine supplementation improve functional capacity in elderly women?

The purpose of this study was to determine the effects of short-term (7 days) oral creatine supplementation (0.3 g.kg(-1)) in elderly women during exercise tests that reflect functional capacity during daily living tasks. We assessed several indices of endurance capacity (1-mile walk test, gross mechanical efficiency, ventilatory threshold, and peak oxygen intake determined during cycle-ergometry) and lower-extremity functional performance (time to complete sit-stand test). Subjects were assigned to a creatine (n = 10; age 67 +/- 6 years) or placebo (n = 6; age 68 +/- 4 years) group. We found a significant improvement only after creatine loading in the sit-stand test (placebo: 9.7 +/- 0.9 seconds for pretest and 9.3 +/- 0.7 seconds for posttest, p > 0.05; creatine: 10.0 +/- 0.7 seconds for pretest and 8.8 +/- 1.1 seconds for posttest). Significance was recorded at p < 0.05 for the interaction effect (group [creatine, placebo] x time [pretest, posttest]). In elderly women, short-term oral creatine supplementation does not improve endurance capacity but increases the ability to perform lower-body functional living tasks involving rapid movements.     

The effect of sodium bicarbonate and sodium citrate ingestion on anaerobic power during intermittent exercise

The effect of sodium bicarbonate and sodium citrate ingestion on cycling performance in three 30 s Wingate Anaerobic Tests separated by 6 min recovery periods has been studied using 6 male subjects. Subjects ingested either sodium bicarbonate (B), sodium bicarbonate plus sodium citrate (BC), sodium citrate (C) or sodium chloride (P) 2.5 h prior to exercise in a dose of 0.3 g kg-1 body weight. Pre-exercise blood pH was 7.44 +/- 0.06, 7.42 +/- 0.05, 7.41 +/- 0.05 and 7.38 +/- 0.04 in the C, BC, B and P conditions respectively. Mean and peak power output were significantly reduced by successive Wingate tests but not significantly affected by the treatments. Performance in the second and third tests was highest following C, BC and B ingestion. The total work done in the 3 tests was 103%, 102% and 101% of that achieved in the P condition after C, BC and B ingestion respectively. The increased alkali reserve recorded subsequent to bicarbonate and citrate treatment reduced mean post-exercise acidosis, although pH was significantly higher only in the C condition (p less than 0.05) compared to P after each exercise bout. No significant differences in plasma lactate concentration were recorded at any time. Citrate ingestion appears to be most effective in elevating blood pH and [HCO3-], and in enhancing performance in short-term intermittent exercise. This study demonstrates that alkali ingestion results in significant shifts in the acid-base balance of the blood and has a small, but non-significant, effect on anaerobic power and capacity as measured in a series of 3 Wingate Anaerobic Tests.