The effect of glucosamine supplementation on people experiencing regular knee pain

OBJECTIVE

The purpose of this study was to examine the effects of oral glucosamine supplementation on the functional ability and degree of pain felt by individuals who had regular knee pain, most likely due to previous articular cartilage damage, and possibly osteoarthritis.

METHODS

Subjects were randomly supplemented with either glucosamine (G) (n=24) or placebo (P) (lactose) (n=22) for 12 weeks at a dose of 2,000 mg per day. Over this period, four testing sessions were conducted, with changes in knee pain and function assessed by clinical and functional tests, (joint line palpation, a 3 metre "duck walk" and a repeated, walking stair climb), two questionnaires (the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Knee Pain Scale (KPS)) and participant subjective evaluations.

RESULTS

The clinical and functional test scores improved with time (main effects: p<0.05, p<0.01) but there were no significant differences between the two groups. The questionnaire results also recorded a significant main effect for time (p<0.05), but the glucosamine group was found to have significantly better KOOS quality of life scores at week eight and 12 (p<0.05), and lower KPS scores (p<0.05) at week eight than the placebo group. On self report evaluations of changes across the 12 week supplementation period, 88% (n=21) of the glucosamine group reported some degree of improvement in their knee pain versus only 17% (n=3) in the placebo group.

CONCLUSIONS

These results suggest that glucosamine supplementation can provide some degree of pain relief and improved function in persons who experience regular knee pain, which may be caused by prior cartilage injury and/or osteoarthritis. The trends in the results also suggest that, at a dosage of 2,000 mg per day, the majority of improvements are present after eight weeks.

Pre-exercise oral creatine ingestion does not improve prolonged intermittent sprint exercise in humans

BACKGROUND

This investigation determined whether pre-exercise oral Cr ingestion could enhance prolonged intermittent sprint exercise performance.

METHODS

EXPERIMENTAL DESIGN

a randomised, double-blind crossover design was employed.

SETTING

testing was performed at the Western Australian Institute of Sport and participants were monitored and treated by both scientific and medical personnel.

PARTICIPANTS

eight active, but not well-trained males with a background in multiple-sprint based sports acted as subjects for this investigation.

INTERVENTIONS

subjects ingested either 15 g Cr.H2O or placebo 120 min and 60 min prior to the start of an 80-min maximal sprint cycling task (10 sets of multiple 6-sec sprints with varying active recoveries). Subjects were retested 14 days later, being required to ingest the alternate supplement and repeat the exercise test.

MEASURES

performance variables (work done and peak power) were obtained throughout the exercise challenge. Muscle biopsies (vastus lateralis) were raised to a peak of 2348+/-223 micromol x l(-1) prior to the commencement of exercise after Cr ingestion. There were no significant changes in any cycling performance parameters following Cr ingestion, although blood La- was significantly lower (p<0.05) than placebo at all time points during were taken preexercise as well as immediately and 3 min post-exercise in order to determine concentrations of ATP, PCr, Cr, La- and glycogen. Venous blood was drawn prior to and on four occasions during the exercise test, and analysed for Cr, NH3+, La- and pH.

RESULTS

Serum Cr concentrations exercise, and plasma NH3+ accumulation was also significantly reduced (p<0.05) in the Cr condition, but only in the second half of the 80-min exercise test. Muscle ATP and TCr levels as well as postexercise PCr replenishment were unaffected following Cr administration.

CONCLUSIONS

The data suggest that although the pre-exercise ingestion of a large Cr dose was shown to have some impact on blood borne metabolites, it does not improve maximal prolonged intermittent sprint exercise performance, possibly due to an insufficient time allowed for uptake of serum Cr by skeletal muscle to occur. Therefore, this form of loading does not provide an alternative method of Cr supplementation to the traditional five-day supplementation regimes established by previous research.

Video analysis of selected game activities in Australian Rules Football

The frequency and outcome of common game activities during Australian football matches have not previously been reported. The aim of this investigation was to determine the frequency and outcome of marking opportunities (MO), ruck contests (RC) and kick-ins (KI). for the purpose of potentially refining current training methods to better replicate common game occurrences. Video footage of all 24 Australian Football League (AFL) matches in which the West Coast Eagles (WCE) participated during the 1997 premiership season was viewed. Notational analysis was used to record information for both the WCE and the opposition during MO, RC and KI. There was an average of 259 MO per game, of which 42.5% were unopposed by either team (1/0 or 0/1) and 45.0% involved one player from each team (1/1). The average success rate of unopposed marks (1/0 and 0/1) was 88.3%, opposed (1/1) 29.3% and, for all MO's combined, 53.5%. There was an average of 99 RC per game, of which 48 were bounce-downs (28 centre bounces) and 51 boundary throw-ins. The clearance rates from RC for WCE and the opposition were not associated with winning the match or each quarter (p> 0.05, R = 0.000), nor did the clearance rate correlate with other measures of game success (scoring shots, team quarter score, the difference in score between teams or the lead change each quarter). There was an average of 21 KI per game. For both teams combined, long kicks (over 50 metres) were the most preferred form of KI (49%) compared to medium (between 25 and 50 metres) (30%) and short (under 25 metres) (21%). Long kicks were the most ineffective at directly retaining possession (29.0%) whilst short kicks were the most effective (93.4%). Some practical (training) implications, based on these results, are discussed.

Effect of Vitamin C and E supplementation on biochemical and ultrastructural indices of muscle damage after a 21 km run

This study investigated whether 4 weeks of daily supplementation with 500 or 1000 mg of Vitamin C and 500 or 1000 IU of Vitamin E could modify biochemical and ultrastructural indices of muscle damage following a 21 km run. Fifteen experienced male distance runners were divided into two groups (vitamin or placebo) and received supplementation for four weeks before completing the first 21 km run in as fast a time as possible. A four-week "washout" period followed before the subjects crossed over and received the alternate supplement for the next four weeks. They then completed a second 21 km run. Before, immediately after and 24 h after each run venous blood samples were taken and analysed for serum creatine kinase, myoglobin, malondialdehyde and vitamin C and E (before-samples only) concentrations. A subgroup of six subjects also had muscle biopsy (gastrocnemius) samples taken 24 h before and 24 h after each 21 km run, which were later analysed by electron microscopy. The two dosages of supplementation produced similar results, so a single vitamin group was formed for further analysis of results. Significant increases (p < 0.05) in creatine kinase and myoglobin, but not in malondialdehyde, were found post-run in both groups. However, no significant differences were found between the vitamin and placebo groups for creatine kinase, myoglobin and malondialdehyde concentrations recorded after the 21 km runs. A qualitative ultrastructural examination of pre-run muscle samples revealed changes consistent with endurance training, but little further change was seen after the 21 km run in either the vitamin or placebo groups. It was concluded that vitamin C and E supplementation (500 or 1000 mg or IU per day) for four weeks does not reduce either biochemical or ultrastructural indices of muscle damage in experienced runners after a half marathon.

The energy cost of running on grass compared to soft dry beach sand

This study compared the energy cost (EC) (J x kg(-1) x m(-1)) of running on grass and soft dry beach sand. Seven male and 5 female recreational runners performed steady state running trials on grass in shoes at 8, 11 and 14 km x h(-1). Steady state sand runs, both barefoot and in shoes, were also attempted at 8 km x h(-1) and approximately 11 km x h(-1). One additional female attempted the grass and sand runs at 8 km x h(-1) only. Net total EC was determined from net aerobic EC (steady state VO2, VCO2 and RER) and net anaerobic EC (net lactate accumulation). When comparing the surface effects (grass, sand bare foot and sand in shoes) of running at 8 km x h(-1) (133.3 m x min(-1)) in 9 subjects who most accurately maintained that speed (133.3 +/- 2.2 m x min(-1)), no differences (P>0.05) existed between the net aerobic, anaerobic and total EC of sand running barefoot or in shoes, but these measures were all significantly greater (P<0.05) than the corresponding values when running on grass. Similarly, when all running speed trials (n = 87) performed by all subjects (n = 13) for each surface condition were combined for analysis, the sand bare foot and sand in shoes values for net aerobic EC, net anaerobic EC and net total EC were significantly greater (P<0.001) than the grass running measures, but not significantly different (P>0.05) from each other. Expressed as ratios of sand to grass running EC coefficients, the sand running barefoot and sand in shoes running trials at 8 km x h(-1) revealed values of 1.6 and 1.5 for net aerobic EC, 3.7 and 2.7 for net anaerobic EC and 1.6 and 1.5 for net total EC respectively. For all running speeds combined, these coefficients were 1.5 and 1.4 for net aerobic EC, 2.5 and 2.3 for net anaerobic EC and 1.5 and 1.5 for net total EC for sand running barefoot and in shoes respectively. Sand running may provide a low impact, but high EC training stimulus.

Clonality of acquired primary pure red cell aplasia: effectiveness of antithymocyte globulin

Primary pure red cell aplasia (PRCA) was diagnosed in two male patients, 65 and 69 years old respectively. In both, surface markers of peripheral blood nuclear cells revealed the presence of TCR alphabeta+ phenotype. Clonality of T cells was confirmed by the polymerase chain reaction in both patients, in whom, prednisone at a dose of 1 mg/kg/day improved the anemia and lower doses caused its renewal, resulting in the reappearance of the patient's transfusion requirement. On the other hand, the anemia seems to have been treated permanently (second case) with horse antithymocyte globulin (ATG) (20 mg/kg/day 1 to 8 +) since his hemoglobin was about 15 g/dl at the time of writing. In the first patient, the hemoglobin level was 10.5 g/dl one month after the administration of ATG (15 mg/kg/d 1 to 5 +), but unfortunately, the patient died because of a massive gastrointestinal bleeding on the fortieth day following this treatment. We, therefore, suggest that, patients with acquired primary PRCA should be screened to detect the presence of a T-cell clone and recommend that, treatment should start earlier with ATG, if the PRCA is due to a T-cell clonal disorder.

Running economy of elite surf iron men and male runners, on soft dry beach sand and grass

The primary aim of this study was to measure the energetics of six elite surf iron men (who participate in regular sand running training), performing steady-state running trials on grass in shoes at 8, 11 and 14 km x h(-1), and on sand bare foot and in shoes, at both 8 and 11 km x h(-1). The net total energy cost (EC, J x kg(-1) x m(-1)) was determined from the net steady-state oxygen consumption and respiratory exchange ratio (net aerobic EC) plus net lactate accumulation (net anaerobic EC). For the sand barefoot and sand in shoes running trials at 8 and 11 km x h(-1), net aerobic EC and total net EC (but not anaerobic EC) were significantly greater (P < 0.001) than the grass running trial values. No differences (P > 0.05) existed between the sand barefoot and sand in shoes trials. These measures were compared with data obtained from eight well-trained male recreational runners who performed the same protocol in a previous study, but who were not accustomed to running on sand. Comparisons of net aerobic EC between the two groups for the surface conditions were not significantly different (P > 0.05). For net anaerobic EC, the iron man values were significantly less (P < 0.02) than the recreational runner values. For net total EC, the iron man values were less than the recreational runner values, but the differences were only significant when both groups ran on sand barefoot (P < 0.03: on grass P = 0.158; on sand in shoes P = 0.103). The lower lactate accumulation values recorded for the iron men on both grass and sand may indicate that running on sand potentially reduces metabolic fatigue when running on firm or soft surfaces.

Muscle glycogen supercompensation: absence of a gender-related difference

Recently it has been reported that women do not have the capacity to accumulate supranormal levels of muscle glycogen when subjected to a carbohydrate (CHO) loading regimen [Tarnopolsky et al. (1995) J Appl Physiol 78:1360-1368]. Since, in this study, CHO intake relative to body mass in the female subjects was much lower than that in males, our primary aim was to re-examine this issue using subjects fed comparable amounts of CHO. Endurance-trained female and male subjects ingested 12 g CHO x kg(-1) lean body mass day(-1) in conjunction with the cessation of their daily physical training. A 3-day exposure to this diet resulted in a marked rise in muscle glycogen levels from [mean (SD)] 108 (15) mmol x kg(-1) wet weight to 193 (14) mmol x kg(-1) wet weight and 111 (16) m mol x kg(-1) wet weight to 202 (20) mmol x kg(-1) wet weight in the female participants during the post-menstrual and pre-menstrual phases of their menstrual cycle, respectively, and from 109 (27) mmol x kg(-1) wet weight to 183 (25) mmol x kg(-1) wet weight in males. We conclude that (1) female athletes have the capacity to accumulate supranormal levels of muscle glycogen, and (2) when exercise-trained males and females are fed comparable amounts of CHO relative to lean body mass, there is no gender-related difference in their ability to accumulate supranormal levels of muscle glycogen.

The level of accuracy and agreement in measures of FEO2, FECO2 and VE between the Cosmed K4b2 portable, respiratory gas analysis system and a metabolic cart

This study aimed to assess the accuracy of the Cosmed K4b2 (Cosmed, Italy) portable metabolic system that measures FEO2, FECO2 and VE on a breath by breath basis. For gas concentration comparisons, expired air from 20 subjects performing treadmill running was collected in a 600 litre chain compensated Collins Tissot tank and analysed for FEO2 and FECO2 using a laboratory metabolic cart and the Cosmed K4 b2 metabolic system. For ventilation comparisons, serial steady state VE (STPD) values were measured on 10 subjects using the Cosmed K4b2 ventilation turbine and a Morgan ventilation monitor during a continuous treadmill running protocol at ascending speeds of 8, 11 and 14 km x h(-1). The Cosmed K4b2 FEO2 and FECO2 measures were significantly lower (P < 0.001) than the metabolic cart values. Pearson correlation coefficients (r) and the standard error of measurement (SEM) demonstrated a high association between the Cosmed and the metabolic cart measures (FEO2 r =0 .971, SEM 0.071: FECO2 r = 0.925, SEM 0.087). Cosmed VE (l x min(-1)) measures were significantly greater than Morgan values at running speeds of 8 kmh(-1) (P < 0.001) and 11 kmh(-1) (P < 0.001) but not significantly different at 14 km x h(-1) (P > 0.05). When VE measures at the three running speeds were combined, the mean difference between instrument measures ranged between 3.5 - 4.0 l x min(-1) but the values were highly correlated (r= 0.982, P<0.01; SEM 3.03). Linear regression analysis revealed the following regression equations to predict metabolic cart values from Cosmed measures: FEO2 = 0.852+0.963 Cosmed (R2 = 0.940, P<0.00 1), FECO2 = 0.627+0.878 Cosmed (R2=0.856, P<0.001), VE = -2.50+0.984 Cosmed (R2 = 0.965. P < 0.001). The results indicated that the Cosmed K4b2 unit assessed here produced measures of FEO2, FECO2 and VE that had strong correlation to values obtained from a metabolic cart. However, linear regression analysis may further improve the accuracy of Cosmed K4b2 measures when compared to metabolic cart values.

In vacuo esterification of carboxyl groups in lyophilized proteins

A new method is described for the esterification of carboxyl groups in proteins by reaction of the lyophilized protein in vacuo with gaseous alcohol and HCI catalyst. Carboxyl groups are rapidly esterified with no protein degradation. 13C-Methyl or 13C-ethyl esters of the alpha-, gamma- and delta-carboxyl groups could be distinguished by the distinct chemical shifts of their resonances. Within the class of gamma- or delta-esters, the chemical shifts have little variation; however, the chemical shift of a C-terminal esterified alpha-carboxyl group shows a strong dependence on the nature of the C-terminal amino acid and sequence. Iodomethane reacts with deprotonated carboxyl groups in lyophilized proteins to form methyl esters, but unlike the reaction with gaseous methanol/HCI, it does not selectively methylate carboxyl groups. The procedure permits the cost-effective incorporation of isotopic labels and provides a new approach using 13C-NMR spectroscopy for determining the number of different C-termini present in a protein preparation.

The effect of three different warm-up intensities on kayak ergometer performance

PURPOSE

The purpose of this study was to investigate the influence of warm-up (WU) intensity on supramaximal kayak ergometer performance.

METHODS

In the initial testing session, eight institute of sport kayak squad members performed a graded exercise test for determination of VO2max and lactate (La) parameters. In a random, counterbalanced order, subjects subsequently performed WU for 15-min at either their aerobic threshold (W1), their anaerobic threshold (W3), or mid-way between their aerobic threshold and anaerobic threshold (W2). A 5-min passive rest period and then a 2-min, all-out kayak ergometer test followed the WU.

RESULTS

For the three different WU conditions, no significant differences were observed for average power, peak VO2, total VO2, total VCO2, or accumulated oxygen deficit (AOD) during the 2-min test. However, when compared with W3, differences in average power approached significance after both W1 (P = 0.09) and W2 (P = 0.10). Furthermore, when compared with W3, average power during the first half of the 2-min test was significantly greater after W2 (P < 0.05) and approached significance after W1 (P = 0.06). After each WU period, there was a significant difference in blood pH (W1>W2>W3; P < 0.05) and blood [La] (W1<W2<W3; P < 0.05). Despite the significantly different metabolic acidemia after each WU condition, there were no significant differences in the VO2 responses to the 2-min test. However, the greater metabolic acidemia after W3 was associated with impaired 2-min kayak ergometer performance.

CONCLUSIONS

It was concluded, that although a degree of metabolic acidemia may be necessary to speed O2 kinetics, if the WU is too intense, the associated metabolic acidemia may impair supramaximal performance by reducing the anaerobic energy contribution and/or interfering with muscle contractile processes.

Brief intense exercise followed by passive recovery modifies the pattern of fuel use in humans during subsequent sustained intermittent exercise

The role of work period duration as the principal factor influencing carbohydrate metabolism during intermittent exercise has been investigated. Fuel oxidation rates and muscle glycogen and free carnitine content were compared between two protocols of sustained intermittent intense exercise with identical treadmill speed and total work duration. In the first experiment subjects (n=6) completed 40 min of intermittent treadmill running involving a work : recovery cycle of 6 : 9 s or 24 : 36 s on separate days. With 24 : 36 s exercise a higher rate of carbohydrate oxidation approached significance (P=0.057), whilst fat oxidation rate was lower (P < or = 0.01) and plasma lactate concentration higher (P < or = 0.01). Muscle glycogen was lower post-exercise with 24 : 36 s (P < or = 0.05). Muscle free carnitine decreased (P < or = 0.05), but there was no difference between protocols. In the second experiment a separate group of subjects (n=5) repeated the intermittent exercise protocols with the addition of a 10-min bout of intense exercise, followed by 43 +/- 5 min passive recovery, prior to sustained (40 min) intermittent exercise. For this experiment the difference in fuel use observed previously between 6 : 9 s and 24 : 36 s was abolished. Carbohydrate and fat oxidation, plasma lactate and muscle glycogen levels were similar in 6 : 9 s and 24 : 36 s. When compared with the first experiment, this result was because of reduced carbohydrate oxidation in 24 : 36 s (P < or = 0.05). There was no difference, and no change, in muscle free carnitine between protocols. A 10-min bout of intense exercise, followed by 43 +/- 5 min of passive recovery, substantially modifies fuel use during subsequent intermittent intense exercise.

Effect of creatine loading on long-term sprint exercise performance and metabolism

PURPOSE

This study examined whether creatine (Cr) supplementation could enhance long-term repeated-sprint exercise performance of approximately 80 min in duration.

METHODS

Fourteen active, but not well-trained, male subjects initially performed 10 sets of either 5 or 6 x 6 s maximal bike sprints, with varying recoveries (24, 54, or 84 s between sprints) over a period of 80 min. Work done (kJ) and peak power (W) were recorded for each sprint, and venous blood was collected preexercise and on four occasions during the exercise challenge. Muscle biopsies (vastus lateralis) were obtained preexercise as well as 0 min and 3 min postexercise. Subjects were then administered either 20 g.d-1 Cr.H2O (N = 7) or placebo (N = 7) for 5 d. Urine samples were collected for each 24 h of the supplementation period. Subjects were then retested using the same procedures as in test 1.

RESULTS

Total work done increased significantly (P < 0.05) from 251.7 +/- 18.4 kJ presupplementation to 266.9 +/- 19.3 kJ (6% increase) after Cr ingestion. No change was observed for the placebo group (254.0 +/- 10.4 kJ to 252.3 +/- 9.3 kJ). Work done also improved significantly (P < 0.05) during 6 x 6 s sets with 54-s and 84-s recoveries and approached significance (P = 0.052) in 5 x 6 s sets with 24-s recovery in the Cr condition. Peak power was significantly increased (P < 0.05) in all types of exercise sets after Cr loading. No differences were observed for any performance variables in the placebo group. Resting muscle Cr and PCr concentrations were significantly elevated (P < 0.05) after 5 d of Cr supplementation (Cr: 48.9%; PCr: 12.5%). Phosphocreatine levels were also significantly higher (P < 0.05) immediately and 3 min after the completion of exercise in the Cr condition.

CONCLUSION

The results of this study indicate that Cr ingestion (20 g.day-1 x 5 d) improved exercise performance during 80 min of repeated-sprint exercise, possibly due to an increased TCr store and improved PCr replenishment rate.

Performance enhancement in rally car drivers via heat acclimation and race simulation

To investigate the combined use of an interactive racecar simulator and heat acclimation on psychomotor (driving) performance, eight rally drivers underwent 4 days of repeated heat (50 degrees C) exposure (1 h x day(-1)) during which they performed a simulated rally drive (3x12-min stages each separated by a 2-min break), after first cycling for 15 min at 125 W to induce some degree of fatigue and heat storage prior to beginning the rally. During the rally stages, a generic set of pace notes were read to the subject by a co-driver. In each simulation, sweat loss, heart rate, core (rectal) and skin temperatures were recorded and driving and psychomotor performance were assessed by recording stage times and time to complete a psychomotor test. Levels of physiological and perceived thermal strain were also recorded. Significant decreases in rally stage times (88 s; P<0.005), psychomotor test time (18 s; P<0.01), final core (0.25 degrees C; P<0.001) and skin (0.44 degrees C; P<0.005) temperatures, heart rate (16 beats x min(-1); P<0.05) and physiological (15 W x m(-2); P<0.005) and perceived thermal (3.7 units; P<0.01) strain were evident by the end of the final simulation, and a significant (P<0.05) increase in sweat sensitivity (+0.33 g x h(-1) x degrees C(-1)) was also recorded. These results suggest that both heat acclimation and race simulation can improve the psychomotor performance of rally drivers, although the relative contribution of each factor was not determined here. However, in a practical setting, these factors would not be used in isolation. After performing the acclimation and simulation protocol prior to an actual rally, drivers subjectively reported improvements in tolerating a high thermal load and in their ability to control the rally vehicle.

The combined effect of heat and carbon monoxide on the performance of motorsport athletes

Two of the major stressors endured by a motorsport athlete (MSA) during a racing event are the effects of heat and carbon monoxide. To date, there has been little research into their combined effect on driving performance. Using an interactive racecar simulator located within an environmental chamber, subjects drove a simulated race (60 min) in environmental conditions similar to those that develop during a NASCAR Winston Cup oval track race (50 degrees C ambient temperature and 10-12% carboxyhaemoglobin levels). Subjects also completed cool (20 degrees C) and heat only (50 degrees C) race simulations. During the simulations, oxygen consumption, heart rate, core and skin temperatures and psychomotor performance were measured. The results demonstrated that exposure to a racecar micro-environment combining both heat and CO produced significantly greater (P<0.05) sweat loss and core temperature change (1.53 kg; 1.06 degrees C) when compared to the heat only (1.14 kg; 0.73 degrees C) and cool conditions (0.35 kg; 0.09 degrees C). Furthermore, a significant decrease (P<0.05) in psychomotor performance was also shown between the heat/CO condition (contact points=38), and both the heat only (25 points) and cool conditions (22 points). It follows that lengthy exposure to these two stressors could produce a substantial decrement in driving performance, thereby endangering the MSA and other race competitors.

Examination of the validity and reliability of the Accusport blood lactate analyser

Clough et al. (1997) reported that 95% of lactate values obtained using an Accusport analyser may be up to 2.6 mM below or 2.1 mM above YSI 2300 analyser values over the range 0-16 mM. This variability is substantial and unsuitable for research purposes, The objectives of this study were to re-examine the specific validity and reliability of an Accusport analyser and to develop a regression equation to improve the accuracy of Accusport measurements. Duplicate measurements of lactate concentration were made on both an Accusport (Boehringer Mannheim) and Analox LM3 Multi Channel analyser on 17 blood samples taken from two subjects performing a discontinuous incremental exercise protocol. Analysis of duplicate measurements revealed good test-retest reliability for Accusport (TEM 0.35 mM; SEM 0.24 mM; ICC r = 0.995) and Analox (TEM 0.07 mM; SEM 0.09 mM; ICC r = 0.999). The mean values for duplicate samples recorded on both the Accusport and Analox between the lactate range of 1-13 mM revealed an average difference between the two analysers of 1.7 mM (P< 0.01, range 1.0-2.9 mM) but values demonstrated a high level of association (ICC r = 0.853; P< 0.05). The level of agreement indicated that in 95% of cases the differences would lie between + 0.5 to + 3.0 mM with the Accusport values always higher than Analox. Linear regression analysis calculated the following equation to predict Analox values from Accusport values: Analox = -0.749 + 0.837Accusport (R2 = 0.990). The results showed the portable Accusport analyser to be reliable and it demonstrated good association with Analox LM3 lactate analyser measures. However, a need exists to develop specifically generated regressions from Accusport and Analox LM3 analyser measures to provide more accurate results when interpreting lactate values from Accusport measures taken in the field.

Simulation and applications of a novel modified SBR system for biological nutrient removal

Dynamic simulation and applications of a novel, continuous-fed, constant level modified sequencing batch reactor for biological nutrient removal are presented. The underlying mathematical model and practical applications of the simulation are discussed. Case studies are presented to illustrate the applications as well as the flexibility of the system in meeting different wastewater treatment requirements. Operation experience from full-scale wastewater treatment plant demonstrates the reliability, ease of operation and high efficiency of the system. Average BOD5, total nitrogen, total phosphorus and TSS removals of 97, 81, 88 and 94% are achieved respectively on an annual basis with little operator attention. Consistently high waste activated sludge concentrations are demonstrated, averaging approximately 20,000 mg/L.

Use of the pH memory effect in lyophilized proteins to achieve preferential methylation of alpha-amino groups

It is demonstrated that the pH memory effect can be used to control the ionization state of amino groups in lyophilized proteins and hence their chemical reactivity toward modifying reagents. When proteins were lyophilized from aqueous solutions at pH values between 6 and 7 and reacted in vacuo with iodomethane, the alpha-amino groups were found to be either preferentially or selectively trimethylated. Reaction with 13C-labeled iodomethane permitted detection and identification of individual trimethylated alpha-amino groups by 13C-NMR spectroscopy as distinct peaks in the spectral region between 52 and 57 ppm. There was adequate sensitivity to detect minor resonances of free alpha-amino groups arising from proteolysis of the major protein or from protein impurities. The resonances of the trimethylated alpha-amino groups in standard amino acids and peptides are sufficiently close to those in the derivatized protein to make a tentative identification of the N-terminal amino acid. It is also demonstrated that advantage can be taken of the pH memory effect to use the preferential 13C-methylation of amino groups to verify whether a protein has a free or blocked amino terminus.

A multistage shuttle swim test to assess aerobic fitness in competitive water polo players

A 10m multistage shuttle swim test (MSST) was designed for the assessment of aerobic fitness of competitive water polo players. Test-retest reliability was determined using a sample of 22 female and 22 male trained water polo players. An intraclass correlation coefficient of 0.99 (p>0.05) was calculated between the two test scores. The technical error of measurement for the test was 2.3 shuttles or 5.0%. The validity of the test was determined using a sample of 13 female and 12 male water polo players. A validation correlation coefficient of 0.88 resulted between the number of shuttles completed during the MSST and VO2max [litres/body surface area/ minute (l x BSA-1 x min-1)] measured during an incremental tethered swim test to exhaustion. A stepwise multiple regression revealed that VO2max (l x BSA-1 x min-1) accounted for approximately 78% of the MSST variance. It was concluded that the 10m multistage shuttle swim test is a reliable and valid field test of aerobic fitness for use with trained water polo players.

The effect of intramuscular iron injections on serum ferritin levels and physical performance in elite netballers

The purpose of this study was to determine the effect of iron supplementation by intramuscular injection on both serum ferritin (SF) levels and exercise performance in iron depleted, non-anaemic elite female netballers. Fifteen iron depleted (Serum Ferritin <40 ug x L(-1). Haemoglobin >125 g x L(-1)) subjects (19+/-3 y) first performed their routine test battery: a vertical jump test, a 10s power and 5x6s repeat sprint test on a cycle ergometer and a 20m multi-stage shuttle run. Subjects were matched on the basis of height, mass, and playing position and then assigned to either a Ferritin Group (FG) or Placebo Group (PG) (single blind design). Subjects then underwent a course of 5x2ml intramuscular injections of either Ferrum H (FG) or normal saline (PG) over a period of 8-10 days before repeating the blood and physical performance tests. Five and 10 days following supplementation, SF levels in the FG increased significantly from baseline levels (P<0.05) and were also significantly greater than levels measured in the PG (P<0.01). Haemoglobin levels remained unchanged in both groups. All test scores remained unchanged from baseline values and were not different between the two groups. These results demonstrate that a course of 5x2ml intramuscular iron injections significantly increased SF concentration within 2 weeks without increasing Hb levels, but this rapid elevation did not enhance the physical performance in selected tests of iron depleted, non-anaemic athletes.

Effect of work and recovery duration on skeletal muscle oxygenation and fuel use during sustained intermittent exercise

The purpose of this study was to compare rates of substrate oxidation in two protocols of intermittent exercise, with identical treadmill speed and total work duration, to reduce the effect of differences in factors such as muscle fibre type activation, hormonal responses, muscle glucose uptake and non-esterified fatty acid (NEFA) availability on the comparison of substrate utilisation. Subjects (n = 7) completed 40 min of intermittent intense running requiring a work:recovery ratio of either 6 s:9 s (short-interval exercise, SE) or 24 s:36 s (long-interval exercise, LE), on separate days. Another experiment compared O(2) availability in the vastus lateralis muscle across SE (10 min) and LE (10 min) exercise using near-infrared spectroscopy (RunMan, NIM. Philadelphia, USA). Overall (i.e. work and recovery) O(2) consumption (VO(2)) and energy expenditure were lower during LE (P < 0.01, P < 0.05, respectively). Overall exercise intensity, represented as a proportion of peak aerobic power (VO2(peak)), was [mean (SEM)] 64.9 (2.7)% VO2(peak) (LE) and 71.4 (2.4)% VO2(peak) (SE). Fat oxidation was three times lower (P < 0.01) and carbohydrate oxidation 1.3 times higher (P < 0. 01) during LE, despite the lower overall exercise intensity. Plasma lactate was constant and was higher throughout exercise in LE [mean (SEM) 5.33 (0.53) mM, LE; 3.28 (0.31) mM, SE; P < 0.001)]. Plasma pyruvate was higher and glycerol was lower in LE [215 (17) microM, 151 (13) microM, P < 0.05, pyruvate; 197 (19) microM, 246 (19) microM, P < 0.05, glycerol]. There was no difference between protocols for plasma NEFA concentration (n = 4) or plasma noradrenaline and adrenaline. Muscle oxygenation declined in both protocols (P < 0.001), but the nadir during LE was lower [52.04 (0. 60)%] compared to SE [61.85 (0.51)%; P < 0.001]. The decline in muscle oxygenation during work was correlated with mean lactate concentration (r = 0.68; P < 0.05; n = 12). Lower levels of fat oxidation occurred concurrent with accelerated carbohydrate metabolism, increases in lactate and pyruvate and reduced muscle O(2) availability. These changes were associated with proportionately longer work and recovery periods, despite identical treadmill speed and total work duration. The proposal that a metabolic regulatory factor within the muscle fibre retards fat oxidation under these conditions is supported by the current findings.

A comparison of skeletal muscle oxygenation and fuel use in sustained continuous and intermittent exercise

In this study we compared substrate oxidation and muscle oxygen availability during sustained intermittent intense and continuous submaximal exercise with similar overall (i.e. work and recovery) oxygen consumption (VO2). Physically active subjects (n = 7) completed 90 min of an intermittent intense (12 s work:18 s recovery) and a continuous submaximal treadmill running protocol on separate days. In another experiment (n = 5) we compared oxygen availability in the vastus lateralis muscle between these two exercise protocols using near-infrared spectroscopy. Initially, overall VO(2) (i.e. work and recovery) was matched, and from 37.5 min to 67.5 min of exercise was similar, although slightly higher during continuous exercise (8%; P < 0.05). Energy expenditure was constant (22.5-90 min of exercise) and was not different in intermittent intense [0.81 (0.01) kJ x min(-1). kg(-1)] and continuous submaximal [0.85 (0.01) kJ x min(-1) x kg(-1)] exercise. Overall exercise intensity, represented as a proportion of peak aerobic power (VO2(peak)), was 68.1 (2.5)% VO2(peak) and 71.8 (1.8)% VO2(peak) for intermittent and continuous exercise protocols, respectively. Fat oxidation was almost 3 times lower (P < 0.05) and carbohydrate oxidation was approximately 1.2 times higher (P < 0.05) during intermittent compared to continuous exercise, despite the same overall energy expenditure. Capillary plasma lactate was constant from 15 to 90 min of exercise, and pyruvate was constant from 15 to 75 min, although both were higher (P < 0.0001, lactate; P < 0.001, pyruvate) during intermittent [5.05 (0.28) mM, 200 (7) microM, respectively] compared to continuous exercise [2.41 (0.10) mM, 114 (4) microM, respectively]. There was no difference between protocols for either plasma glycerol or non-esterified fatty acids. The decrease in muscle oxygenation during work periods of intermittent exercise resulted in a lower nadir oxygenation [54.62 (0.41)%] compared to continuous exercise [58.82 (0.21)%, P < 0.001]. The decline in oxygenation was correlated with treadmill speed (r = 0.72; P < 0.05). These results show a difference in substrate utilisation and muscle oxygen availability during sustained intermittent intense and continuous submaximal exercise, despite a similar overall VO(2) and identical energy expenditure.

Elemental composition of human milk from mothers of premature and full-term infants during the first 3 months of lactation

To examine longitudinal and gestational effects of mineral content in human milk, we analyzed human milk from lactating mothers of premature (PRT, n = 24, < 2000 g birth weight, < 37 wk gestation) and full-term (FT, n = 19, > 2500 g, 39-41 wk gestation), living in Newfoundland, Canada. Samples were collected once a week for 8 wk with one final sample collected at 3 mo. Milk samples collected in acid-washed containers were wet ashed with concentrated HNO3, and barium, cadmium, calcium, cesium, cobalt, copper, cerium, lanthanum, magnesium, manganese, molybdenum, nickel, lead, rubidium, tin, strontium, and zinc were measured using inductively coupled plasma-mass spectrometry. Data were analyzed using standard multiple-regression procedures with correlated data analyses to take account of the relationship between successive weeks. Results indicated lower Ca and Pb in PRT milk. Calcium was the only nutritionally significant element to differ between groups. Molybdenum in both PRT and FT milk showed a definite decrease with time, suggesting that the Mo content in milk is homeostatically regulated. However, Ce, La, Ba, and Sn did not display any pattern indicative of biological regulation and potential human requirement.