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Biomedical subjects

D Docherty

Publications and source records attributed to D Docherty.

15 recordsLinked to original sources
PubMed2006

Acute neuromuscular responses to resistance training performed at different loads.

The aim of this study was to compare the acute neuromuscular responses during resistance exercise performed with different loading protocols. Thirteen (N=13) college-aged male subjects experienced in weight training completed two different weight training protocols involving a single elbow flexion exercise. During both protocols subjects performed three sets of the exercise with a 3-min rest between each set. One protocol required the subjects to perform each set to failure using 100% 10 repetition maximum (RM) load whereas the second protocol required the subjects to perform 10 repetitions for the first two sets using 90% 10RM load and only go to failure on the third set. Maximal voluntary isometric contraction (MVIC), integrated EMG recording (iEMG) of the biceps brachii, and blood lactate were measured before and upon completion of the two training protocols. Subjects were able to perform a significantly greater volume of work (total repetitionsxload) in the 90% 10RM protocol compared to the 100% 10RM protocol. Both protocols elicited similar cumulative levels of fatigue as reflected by a decrease in MVIC and iEMG(max) and an increase in blood lactate (p< or =0.05). As a result of the drop in repetitions performed in successive sets, it was concluded that training with 100% 10RM while exercising to failure in each set may not optimise the training volume, which may have implications for chronic muscle adaptation.

Adult↗
PubMed2003

Evaluation of the Dade Behring Syva EMIT 2000 tacrolimus assay on the Bayer Advia 1650.

BACKGROUND: The Dade Behring Syva(R) EMIT (enzyme multiplied immunoassay technique) method for the measurement of tacrolimus in whole blood was evaluated against the Abbott IMx(R) microparticle enzyme immunoassay (MEIA) method. EMIT measures tacrolimus colorimetrically, whereas MEIA measures the analyte using fluorimetry. Both methods incorporate a protein precipitation step prior to measurement. METHOD: Whole blood specimens were treated by two types of precipitation technique followed by analysis for tacrolimus by either MEIA or EMIT on the Bayer Advia 1650. Linearity and precision were assessed and correlation analysis performed to evaluate the EMIT assay on the Bayer Advia 1650. RESULTS: The EMIT tacrolimus assay was linear over the concentration range 0.0-22.0 micro g/L; the limit of detection was 1.2 micro g/L. Correlation between the Syva EMIT and IMx tacrolimus assays was excellent (r = 0.959) and no significant bias existed between the two methods (mean difference, delta = 0.221 micro g/L). Calibration data for the EMIT assay was stable for a period of 24-48 h on the Advia between runs. CONCLUSION: The Syva EMIT assay for the measurement of tacrolimus in whole blood is suited for daily routine use on the Bayer Advia 1650.

Blood Chemical Analysis↗
PubMed2000

A proposed model for examining the interference phenomenon between concurrent aerobic and strength training.

A review of the current research on the interference phenomenon between concurrent aerobic and strength training indicates modest support for the model proposed in this article. However, it is clear that without a systematic approach to the investigation of the phenomenon there is lack of control and manipulation of the independent variables, which makes it difficult to test the validity of the model. To enhance the understanding of the interference phenomenon, it is important that researchers are precise and deliberate in their choice of training protocols. Clear definition of the specific training objectives for strength (muscle hypertrophy or neural adaptation) and aerobic power (maximal aerobic power or anaerobic threshold) are required. In addition, researchers should equate training volumes as much as possible for all groups. Care needs to be exercised to avoid overtraining individuals. There should be adequate recovery and regeneration between the concurrent training sessions as well as during the training cycle. The model should be initially tested by maintaining the same protocols throughout the duration of the study. However, it is becoming common practice to use a periodised approach in a training mesocycle in which there is a shift from high volume and moderate intensity training to tower volume and higher intensity. The model should be evaluated in the context of a periodised mesocycle provided the investigators are sensitive to the potential impact of the loading parameters on the interference phenomenon. It may be that the periodised approach is one way of maintaining the training stimulus and minimising the amount of interference. The effects of gender, training status, duration and frequency of training, and the mode of training need to be regarded as potential factors effecting the training response when investigating the interference phenomenon. Other experimental design factors such as unilateral limb training or training the upper body for one attribute and the lower body for another attribute, may help establish the validity of the model.

Adaptation, Physiological↗
PubMed1995

Differences in anaerobic performance between boys and men.

The purpose of this study was to compare the anaerobic performance of 11-12 year old prepubescent boys (stage 1; n = 18) using a maximal effort 90 s cycling test to that of adult men (n = 19). Performance was separated into short-term anaerobic power (SAP; work in 10 s), intermediate-term anaerobic capacity (IAC; work in 30 s) and long-term anaerobic capacity (LAC; work in 90 s). Resistance on the Monark cycle ergometer was chosen as the highest tolerable load for the 90 s test and set at 2.6 and 3.8 J. rev-1.kg body mass-1 for boys and men, respectively. Power drop-off (%PD) was determined as the change in 5 s power outputs from 0-90 s. Blood lactates were measured at rest (pretest; BL) and at 2 (BL2) and 5 (BL5) min post test. Absolute and relative (to weight or thigh volume) scores for SAC, IAC and LAC were 33-40% lower in the boys compared to the men (p < 0.001). The men demonstrated significantly greater %PD over the 90 s (32.2%) compared to the 25.3% PD of the boys (p < 0.001), suggesting that the development of fatigue was greater in the men even though power and work outputs were high. Resting BL values were similar for both groups. Mean BL2 and BL5 were higher (p < 0.01) in the men (13.5, SD = 3.4; 12.5, SD = 2.8 mmol.l-1) than in the boys (9.1, SD = 1.7; 8.3, SD = 1.6 mmol.l-1). The anaerobic performance of the boys compared to the men cannot be completely explained by the lower resistance setting used. Although the boys were 50% lighter than the men, their resistance was 70% of that used for the men. The results do not support the contention that children and adults have similar abilities in short term, exhaustive work when corrected for size. Prepubescent boys appear to be limited in their ability to perform short-term as well as intermediate and long term anaerobic exercise compared to adult males.

Adult↗
PubMed1995

The effect of an aerobic interval training program on intermittent anaerobic performance.

The effects of a 9-week aerobic interval training program on anaerobic intermittent performance were investigated. Intermittent work consisted of four repeat 30-sec maximal efforts on a cycle ergometer (Wingate test) with 3-min recovery intervals. Thirteen men trained 3 days a week on the cycle ergometer, completing 3-min work-to-rest intervals and progressing from 5 to 10 reps. Relative and absolute values of aerobic power increased significantly for the training group (p < .05). No significant change was observed for the control group (n = 11). The training group demonstrated significant increases in the four anaerobic variables of short-term peak power (SPP), short-term anaerobic capacity (SAC), intermediate-term peak power (IPP), and total work (TW), and across the four 30-sec maximal repeats for anaerobic performance (T1-T4) (p < .05). Greater percentages of increase occurred for IPP and TW, especially during Repeats 3 and 4. The control group only demonstrated a significant increase in SPP for Repeat 3. These data suggest that the type of interval training program used in the study increased aerobic power and also enhanced performance in repeated high intensity, short duration work.

Adult↗
PubMed1993

Subarachnoid local anesthetic block does not affect morphine absorption from paired intramuscular and subcutaneous injection sites in the elderly patient.

Morphine absorption from subcutaneous and intramuscular injection sites is dependent on local skin and muscle blood flow. Normally, drug absorption from intramuscular and subcutaneous injections at the same anatomical site is comparable, but spinal anesthesia alters muscle and skin blood flow in the blocked area. This study measured morphine absorption from pairs of intramuscular and subcutaneous injection sites at vastus lateralis and deltoid following a single dose of morphine sulfate in the presence of spinal anesthesia. Differences between the maximum concentration achieved after injection (Cmax) and the time at which this occurred (Tmax) were not significant when absorption for each "same-site" pair of injections was compared, but Tmax after intramuscular injection at vastus lateralis was significantly longer than that observed following either intramuscular or subcutaneous injection at the deltoid (P < 0.05 for both comparisons). Cmax/Tmax ratios and the area under concentration time curve (AUC) also were analyzed, but there were no statistically significant differences among any of the four groups.

Absorption↗
PubMed1991

Relationship of body size, physique, and composition to physical performance in young boys and girls.

The present study examined the aerobic, anaerobic and strength performance characteristics of 52 young boys and girls (mean age 10.8 and 11.1 yrs, respectively) on selected laboratory measures. Anthropometrically, the boys and girls were similar, with the exception of measures of body fatness. The boys demonstrated greater values in maximal aerobic power, anaerobic performance, (especially related to body weight), and strength relative to lean body mass. Since body size measures, including height, were similar, the functional differences could not be attributed to such factors. The significant but low correlations between the performance variables failed to support the concept of children as "metabolic non-specialists" as proposed by previous authors. In fact, the large amount of variance not accounted for could be interpreted as supporting the unique contribution of genetic endowment of the effect of habitual activity patterns on the performance measures. Canonical correlations indicated a strong relationship between selected anthropometric and performance variables (rc = .94). For boys, height and weight were strongly related to anaerobic performance, whereas weight and thigh volume were strongly related to all performance measures for the girls.

Adipose Tissue↗
PubMed1987

Embryotoxicity, teratogenicity, and aryl hydrocarbon hydroxylase activity in Forster's terns on Green Bay, Lake Michigan.

Known reproductive problems, including congenital malformations and poor hatching success, exist for the state endangered Forster's tern (Sterna forsteri) in Green Bay, Wisconsin. Twenty Forster's tern eggs were collected from separate nests at a natural colony with documented reproductive problems, situated at Green Bay, Lake Michigan, and an inland colony at Lake Poygan (control) where reproduction was documented as normal. Eggs from the two locations were placed in the same laboratory incubator and candled throughout incubation. Hatching success of Green Bay eggs was 52% of that for controls. Several early embryonic deaths occurred, but most mortality occurred close to the time of hatching. Liver microsomal aryl hydrocarbon hydroxylase activity was elevated approximately threefold in Green Bay hatchlings compared to controls. Green Bay terns that hatched weighed less than controls, had an increased liver to body weight ratio, and had a shorter femur length. Two Green Bay embryos that failed to hatch had anomalies, one with a crossed beak and one with poor ossification of the foot. One Green Bay hatchling had an abnormally ossified ilium. These effects were observed in eggs where there were measureable levels of aryl hydrocarbon hydroxylase inducers including polychlorinated biphenyls and polychlorinated dibenzo-p-dioxins.

Animals↗
PubMed1987

The effects of resistance training on aerobic and anaerobic power of young boys.

A 4-wk interval-type training program incorporating omni-kinetic equipment and stationary cycling elicited an increase in the absolute and relative VO2max of an active group of young boys. The improvement in aerobic function was independent of the training protocols of high velocity-low resistance and low velocity-high resistance. However, the training programs failed to increase anaerobic function as measured by an "all-out" cycle test in which power output was calculated in watts and watts per kilogram for 0- to 15-s and 15- to 30-s work periods. Changes in aerobic and anaerobic functions were independent of physiological maturity as determined by serum testosterone level (ng X dl-1).

Adolescent↗
PubMed1986

Physique and thermoregulation in prepubertal males during exercise in a warm, humid environment.

The hyperthermic response to exercise in a warm (30 degrees C), humid (80% relative humidity) environment was obtained for 23 prepubertal males. After the initial increase of core temperatures (tympanic and rectal) to elevated set points, further hyperthermia was minimal and was unrelated to any physique variable except for the case of endomorphy, which was weakly correlated with hyperthermia at the rectal site. This result for boys is attributed to the combination of small body size (relative to adults) and absence of pronounced, age-dependent muscular development as evidenced by low rating and small variation of the mesomorphy component of somatotype. Both of these factors were associated with a high surface area to weight ratio compared to adults, which facilitated heat loss. It is concluded that prepubertal males thermoregulate efficiently during moderate exercise in a warm, humid environment. Other than cases of obesity, variation in physique is not an important consideration for assessing the risk of heat strain.

Adolescent↗
PubMed1982

A comparison of heart rate responses in racquet games.

The present study investigated the heart rate response to playing tennis with special reference to the skill levels and ages of the participants. Data obtained in a similar manner during earlier studies of badminton and squash players were compared with that obtained during tennis. The number of rallies, mean rally time and actual playing time in 30 minutes of play was also compared for the different skill levels and sports. Results showed that playing tennis raised the players' heart rates to 68-70% of their predicted maximum heart rate (PMHR). Playing squash and badminton could raise heart rates to 80-85% of the players' PMHR which was significantly higher than the values obtained for tennis. The actual skill level of the participants within their chosen sport did not have a significant effect in predicting the physical demands of squash or tennis but was important in predicting the heart rate response of badminton players. The more skillful the badminton player the greater the cardiac response as a result of game play. Analysis of time spent in actual play revealed that tennis players were involved in play for only five of the thirty minutes of game play, compared to 15 and 10 min respectively for squash and badminton. Skill level within each sport was only a significant factor in predicting length of play for squash players in which the medium and highly skilled groups played significantly longer than those of a lower level of skill.

Age Factors↗
PubMed1982

Relationship of disembedding ability to performance in volleyball, tennis, and badminton.

The study was designed to determine the relationship between different perceptual abilities and performance in volleyball, badminton, and tennis. 41 boys and 37 girls enrolled in a Grade 10 physical education program served as subjects. Performance in the three sports and four perceptual ability measures were determined. A multiple regression analysis indicated that the Group Embedded Figures Test was the most consistent perceptual measure for predicting significant motor performance but accounted for only 8 to 20% of the actual variance. Further, multiple regression analysis confirmed the importance of previous experience in a specific sport which accounted for 24 to 50% of the variance.

Adolescent↗