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Biomedical subjects

G W Fellingham

Publications and source records attributed to G W Fellingham.

At least 19 recordsLinked to original sources
PubMed2002

A method for meta-analysis where the level of data aggregation differs between studies.

BACKGROUND: This paper presents a statistical method that was used to assess haemoglobin levels world-wide among women, based on a combination of over 400 studies. METHODS: The methodology is easy to implement and is specifically adapted to the case where mean observations are taken, although the subgroups represented by the mean values may differ from study to study. That is, the level of data aggregation is not consistent between studies. RESULTS: In this example some studies report average haemoglobin levels for a sample of the population, while others give averages by urban/rural classification and/or pregnancy status. Though the method is based on likelihood principles, computation is straightforward. CONCLUSIONS: The methodology can be applied to a variety of meta-analytic situations where assessments are based on combining data from several sources. We provide an example of how the method was implemented in a study of haemoglobin levels among women undertaken at the World Health Organisation.

Data Collection↗
PubMed2001

Stroke volume does not plateau during graded exercise in elite male distance runners.

UNLABELLED: Stroke volume (SV) responses during graded treadmill exercise were studied in 1) elite male distance runners (N = 5), 2) male university distance runners (N = 10), and 3) male untrained university students (N = 10). METHODS: Cardiac output (Q) and SV were determined by a modified acetylene rebreathing procedure. RESULTS: There were no differences in SV responses among the three groups during the transition from rest to light exercise (P > 0.05). However, the rates of change of SV during light to maximal exercise in untrained subjects (slope = -0.1544 mL x beat(-1)) and university distance runners (slope = 0.1041) did not change, whereas it dramatically increased (P < 0.001) in elite distant runners (slope = 0.6734). Moreover, the elite distance runners showed a further slope increase in SV when heart rate was above 160 bpm, which resulted in an average maximal SV of 187 +/- 14 mL x beat(-1) compared with 145 +/- 8 and 128 +/- 14 mL x beat(-1) in the university runners and untrained students, respectively (P < 0.001). Similarly, max Q reached 33.8 +/- 2.3, 26.3 +/- 1.7, and 21.3 +/- 1.5 L x min(-1) in the three groups, respectively (P < 0.001). On the other hand, there was a nonsignificant tendency for maximal arteriovenous oxygen content difference to be lower in the elite athletes compared with the other groups. CONCLUSION: Results from university distance runners and untrained university students support the classic observation that SV plateaus at about 40% of maximal oxygen consumption despite increasing intensity of exercise. In contrast, stroke volume in the elite athletes does not plateau but increases continuously with increasing intensity of exercise over the full range of the incremental exercise test.

Adult↗
PubMed2001

The effect of duration of stretching of the hamstring muscle group for increasing range of motion in people aged 65 years or older.

BACKGROUND AND PURPOSE: Stretching protocols for elderly people (> or = 65 years of age) have not been studied to determine the effectiveness of increasing range of motion (ROM). The purpose of this study was to determine which of 3 durations of stretches would produce and maintain the greatest gains in knee extension ROM with the femur held at 90 degrees of hip flexion in a group of elderly individuals. SUBJECTS: Sixty-two subjects (mean age = 84.7 years, SD = 5.6, range = 65-97) with tight hamstring muscles (defined as the inability to extend the knee to less than 20 degrees of knee flexion) participated. Subjects were recruited from a retirement housing complex and were independent in activities of daily living. METHODS: Subjects were randomly assigned to 1 of 4 groups and completed a physical activity questionnaire. The subjects in group 1 (n = 13, mean age = 85.1 years, SD = 6.4, range = 70-97), a control group, performed no stretching. The randomly selected right or left limb of subjects in group 2 (n = 17, mean age = 85.5 years, SD = 4.5, range = 80-93), group 3 (n = 15, mean age = 85.2 years, SD = 6.5, range = 65-92), and group 4 (n = 17, mean age = 83.2 years, SD = 4.6, range = 68-90) was stretched 5 times per week for 6 weeks for 15, 30, and 60 seconds, respectively. Range of motion was measured once a week for 10 weeks to determine the treatment and residual effects. Data were analyzed using a growth curve model. RESULTS: A 60-second stretch produced a greater rate of gains in ROM (60-second stretch = 2.4 degrees per week, 30-second stretch = 1.3 degrees per week, 15-second stretch = 0.6 degrees per week), which persisted longer than the gains in any other group (group 4 still had 5.4 degrees more ROM 4 weeks after treatment than at pretest as compared with 0.7 degrees and 0.8 degrees for groups 2 and 3, respectively). DISCUSSION AND CONCLUSION: Longer hold times during stretching of the hamstring muscles resulted in a greater rate of gains in ROM and a more sustained increase in ROM in elderly subjects. These results may differ from those of studies performed with younger populations because of age-related physiologic changes.

Aged↗
PubMed2000

Exercise after cryotherapy greatly enhances intramuscular rewarming.

OBJECTIVE: To determine the effect of moderate-intensity walking on rewarming of the triceps surae muscle group after a 20-minute application of a crushed-ice pack. DESIGN AND SETTING: Subjects were randomly assigned to either the ice-rest or the ice-exercise group. All subjects were treated on the left calf for 20 minutes with a 1.8-kg ice pack. The ice-exercise group walked on a treadmill at 5.63 km/h for 10 minutes and then assumed a prone position on an examining table for 20 minutes. The ice-rest group assumed a prone position on an examining table for 30 minutes after the cryotherapy treatment. SUBJECTS: Twenty-eight (19 men and 9 women) college-student volunteers. MEASUREMENTS: Intramuscular temperature was recorded at 10-second intervals for 50 minutes at 1 cm below the subcutaneous fat with a thermocouple implanted via a 21-gauge sterile hypodermic needle. Differences were analyzed within and between groups at pretreatment (T(0)), the end of the ice treatment (T(20)), 11 minutes after the end of ice treatment (T(31)), and 30 minutes posttreatment (T(50)). RESULTS: We found no differences at T(0) and T(20) but significant differences at T(31) and T(50). At T(31), the ice-exercise group was only 0.61 degrees C colder than at pretreatment levels, while the ice-rest group was 8.05 degrees C colder. By T(50), the temperatures were 0.93 degrees C and 6.95 degrees C colder, respectively, than at pretreatment levels. CONCLUSION: Moderate walking significantly enhanced rewarming of the triceps surae.

Journal Article↗
PubMed1998

Temperature changes in the human leg during and after two methods of cryotherapy.

OBJECTIVE: To compare the cooling and rewarming effects of two clinical 20-minute cryotherapy treatments on the temperature of the human leg. DESIGN AND SETTING: Sixteen subjects were randomly treated with either 20 minutes of a 1.8-kg crushed-ice pack, placed directly over the left calf, or a 20-minute immersion in a cold (10 degrees C) whirlpool. Data were collected at a university human performance research laboratory. SUBJECTS: Seventeen male and 15 female healthy college students. MEASUREMENTS: Subcutaneous and muscle tissue temperatures were measured by 26-gauge hypodermic needle microprobe inserted in the calf, just below the skin, or 1 cm below the subcutaneous fat, respectively. RESULTS: There was no significant difference in the decrease in intramuscular temperatures between treatments (t (30) = -1.76, P = .09). The ice pack treatment significantly decreased the subcutaneous temperature more than the whirlpool (t (30) = -2.64, P = .01). The subcutaneous temperature rewarmed significantly more in the ice pack group (12.3 +/- 3.3 degrees C) than the cold whirlpool (7.4 +/- 2.1 degrees C) (t (30) = 4.98, P = .0000). The ice pack group's intramuscular temperature increased over each 5-minute interval of the 30-minute post-treatment period for an overall increase of 2.0 +/- 3.1 degrees C. During the 30-minute post- treatment the cold whirlpool group continued to cool, for an overall decrease of 1.8 +/- 1.4 degrees C. This difference between groups at the end of the 30-minute post-treatment was significant (t(30) = 4.44, P = .0001). CONCLUSIONS: As administered in our protocol, cold whirlpool is superior to crushed-ice packs in maintaining prolonged significant temperature reduction after treatment.

Journal Article↗
PubMed1997

Cold- and hot-pack contrast therapy: subcutaneous and intramuscular temperature change.

OBJECTIVE: To investigate the temperature changes in subcutaneous and intramuscular tissue during a 20-minute cold- and hot-pack contrast therapy treatment. DESIGN AND SETTING: Subjects were randomly exposed to 20 minutes of contrast therapy (5 minutes of heat with a hydrocollator pack followed by 5 minutes of cold with an ice pack, repeated twice) and 20 minutes of cold therapy (ice pack only) in a university laboratory. SUBJECTS: Nine men and seven women with no history of peripheral vascular disease and no allergy to cephalexin hydrochloride volunteered for the study. MEASUREMENTS: Subcutaneous and intramuscular tissue temperatures were measured by 26-gauge hypodermic needle microprobes inserted into the left calf just below the skin or 1 cm below the skin and subcutaneous fat, respectively. RESULTS: With contrast therapy, muscular temperature did not fluctuate significantly over the 20-minute period compared with the subcutaneous temperature, which fluctuated from 8 degrees C to 14 degrees C each 5-minute interval. When subjects were treated with ice alone, muscle temperature decreased 7 degrees C and subcutaneous temperature decreased 17 degrees C over the 20-minute treatment. CONCLUSIONS: Our results show that contrast therapy has little effect on deep muscle temperature. Therefore, if most of the physiologic effects attributed to cold and hot contrast therapy depend on substantial fluctuations in tissue temperature, contrast therapy needs to be reconsidered as a viable therapeutic modality.

Journal Article↗
PubMed1996

Cocaine and exercise: temporal changes in plasma levels of catecholamines, lactate, glucose, and cocaine.

To determine the combined sympathoadrenal effects of cocaine and exercise in awake animals, rats were assigned to one of four treatment groups: saline-rest (SR), saline-exercise (SE), cocaine-rest (CR), and cocaine-exercise (CE). Venous blood samples from jugular catheters were obtained at -40, 0-4, 7, 10, 13, 16, 19, 26, and 36 min after intravenous injection of cocaine (5 mg/kg) or saline and the simultaneous onset of a 16-min treadmill run (26 m/min, 10% grade). CE increased plasma epinephrine (24.2 nM at 16 min), norepinephrine (28.0 nM at 10 min), and lactate (11.2 mM at 4 min) to levels 2-5 times greater than either treatment (SE and CR) alone (P<0.05) and 11-35 times higher that SR. Blood glucose values were significantly depressed in CE (-33% vs. SE) but increased in CR (+26% vs. SR). Plasma cocaine peaked < 2 min after injection in both CR and CE, and the peak was 69% higher in CE (P<0.05); however, the plasma elimination half-life (12-14 min) was not different. These results indicate that the combined effect of the two sympathoadrenal stimulants, exercise and cocaine, amplify the catecholamine responses to levels far greater than when each stimulant is used alone.

Animals↗
PubMed1996

Cocaine and exercise: alteration in carbohydrate metabolism in adrenodemedullated rats.

The combined treatment of cocaine-exercise (CE) causes an exaggerated catecholamine response, a rapid depletion of muscle glycogen, and accumulation of lactic acid. To assess the contribution of the adrenal medulla in the catecholamine response and to determine the role of epinephrine (Epi) on carbohydrate metabolism, cocaine (20 mg/kg ip) or saline was injected into sham-operated (Sham) or adrenodemedullated (AdM) rats, which then ran for 5 min at 56 m/min, 0% grade. In Sham rats, CE caused plasma Epi values (means +/- SE) to rise to 27.7 +/- 6.9 nM compared with 13.3 +/- 1.5 nM in saline-exercise (SE) and 0.8 +/- 0.2 nM in both AdM-CE and AdM-SE animals (P < 0.05). With minimal Epi in AdM, CE still caused glycogen to fall to lower levels (25.4 +/- 3.0 mumol/g vs. 40.5 +/- 2.4 mumol/g) and lactate to rise to higher levels (17 +/- 3 vs. 9 +/- 1 mumol/kg) in white vastus muscle than in SE group (P < 0.05). CE had no significant effect on soleus and red vastus glycogenolysis but it did cause lactate accumulation in red vastus. As a result, plasma lactate levels were also higher after CE compared with SE in AdM (17.9 +/- 2.0 vs. 8.5 +/- 0.5 mM, P < 0.05). We conclude that during CE 1) Epi is not essential to the alteration in carbohydrate metabolism; 2) the latter may be related to the other catecholamines; 3) the adrenal medulla is the only source of Epi; and 4) the adrenal medulla is not the source of the increased levels of norepinephrine or dopamine.

Adrenal Medulla↗
PubMed1995

Cocaine and exercise: physiological responses of cocaine-conditioned rats.

To compare the physiological response to a cocaine-exercise challenge in cocaine-conditioned animals with that of acute-cocaine animals, rats were injected i.p. with either cocaine (20 mg.kg-1) or saline, twice daily for 14 consecutive days. On the 15th day (test day) cocaine-conditioned rats received an i.v. injection of cocaine (5 mg.kg-1) (chronic group). One-half of the chronic saline rats also received the cocaine injection (acute group), while the other half received saline (saline group). Immediately after injection, all rats were either rested or exercised (22 m.min-1, 10% grade) for 30 min. For most parameters there was no difference between the responses of the chronic and acute cocaine groups at rest or to the cocaine-exercise challenge. During exercise, both cocaine groups had similarly higher lactate values than the saline animals (P < 0.05). Both groups had similarly greater reductions in glycogen content of the white and red vastus muscles than occurred in the saline group; and both groups had similar increases in corticosterone. In contrast, cocaine-conditioned animals had a greater rise in norepinephrine (P < 0.059) and epinephrine (P < 0.001) in response to cocaine-exercise than did the acute group. The mechanism responsible for the exaggerated catecholamine response in the chronic cocaine animals is unknown.

Adaptation, Physiological↗
PubMed1994

Developing an optimal scoring system with a special emphasis on volleyball.

Scoring systems for two-team (two-person) net games are typically evaluated for accuracy, efficiency, and variability. This evaluation may be difficult if many points are involved, the probability of winning a point changes with service, and/or points are not scored every rally. A computer program that may be used to evaluate general scoring systems for accuracy, efficiency, variability, and expected score difference is presented. Four scoring systems, side-out, quick, side-out point, and bonus point, are analyzed. A list of items to consider when developing an optimal scoring system is suggested. An optimal scoring system for volleyball is introduced.

Humans↗
PubMed1994

Effects of cocaine on glycogen metabolism and endurance during high intensity exercise.

Because cocaine causes a rapid sympathetic response and central euphoria, we tested whether it would improve endurance or alter carbohydrate metabolism during high-intensity activity. Thirty male rats (10 animals/group) were injected intraperitoneally with either saline (S) or one of two doses of cocaine-HCl (12.5 (C-1) or 20.0 (C-2) mg.kg-1 b.w.). Ten minutes later they began gradually running on a rodent treadmill. Within 2 min they were running at 56 m.min-1 until fatigued. The run time to exhaustion (mean +/- SE) for C-2 (569 +/- 97 s) was less than S (859 +/- 71) and C-1 (923 +/- 65) (P < 0.05) and 25% shorter (marginally insignificant) than a pretreatment run (754 +/- 67 s) (P > 0.05). Plasma lactate concentrations at exhaustion were 4.0 +/- 0.5 (S), 7.3 +/- 1.1 (C-1), and 13.9 +/- 2.5 (C-2) mmol (P < 0.05, S vs C-2). Lactate concentrations in white vastus muscle were also elevated by C (4.7 +/- 0.6 (S), 8.1 +/- 1.3 (C-1), and 15.0 +/- 3.7 (C-2) mumol.g-1, (P < 0.05, S vs C-2)], which correlated with the reduction in glycogen content in both C groups (9.9 +/- 2.3 (C-2), 10.3 +/- 1.2 (C-1), vs 33.9 +/- 2.0 (S) mumol.g-1]. These results show that, in spite of its purported stimulatory effect, cocaine treatment (20 mg.kg-1) immediately prior to intense exercise causes accelerated glycogen degradation and lactate accumulation in white vastus muscle during exercise and premature fatigue.

Analysis of Variance↗
PubMed1993

Cryotherapy and sequential exercise bouts following cryotherapy on concentric and eccentric strength in the quadriceps.

We investigated the effects of cryotherapy followed by sequential exercise bouts on concentric and eccentric strength of the quadriceps. Nineteen males (18-27 years) participated in a two-stage design involving four sequences: ice and exercise, ice and rest, no ice and exercise, and no ice and rest. We gathered concentric and eccentric strength measures (torque) using a kinetic communicator (KIN-COM) prior to exercise, immediately following treatment, and 20- and 40-minutes post-treatment. There were significant decreases in concentric and eccentric strength immediately following the 25-minute cryotherapy treatment. This suggests that applying ice immediately prior to participation or returning an athlete to competition immediately following cryotherapy treatment may adversely affect his/her ability to perform. It appears that the reduction in strength following cryotherapy is of short duration (less than 20 minutes). The delayed effect of the ice treatment and sequential exercise appears to affect concentric and eccentric strength differently. Ice did not have a delayed effect on concentric strength, but there was a significant difference in eccentric values. This difference was a failure to improve during post-tests at the rate of those not treated with ice. Exercise did not have a significant effect on eccentric strength recovery, but there was a significant difference in concentric values. Moderate exercise following cryotherapy appears to help the recovery of concentric strength.

Journal Article↗
PubMed1993

VO2max estimation from a submaximal 1-mile track jog for fit college-age individuals.

The primary purpose of this study was to develop a submaximal field test for the estimation of maximal oxygen uptake (VO2max) using a 1-mile track jog. A second purpose was to determine the accuracy of the 1.5-mile run in estimating VO2max for both male and female subjects. VO2max was measured in 149 relatively fit college students (males = 88, females = 61) 18-29 yr using a treadmill protocol (mean +/- SD; VO2max = 47.7 +/- 6.3 ml.kg-1 x min-1). Multiple regression analysis (N = 54) to estimate VO2max from the submaximal, steady-state 1-mile track jog yielded the following validation (V) model (r(adi) = 0.87, SEE = 3.0 ml.kg-1 x min-1): VO2max = 100.5 + 8.344* GENDER (0 = female; 1 = male) - 0.1636* BODY MASS (kg) - 1.438* JOG TIME (min.mile-1) - 0.1928* HEART RATE (bpm). To help ensure that a submaximal level of exertion was realized for the 1-mile track jog, elapsed jog time was restricted to > or = 8.0 min for males and > or = 9.0 min for females and exercise HR to < or = 180 bpm. Cross-validation (CV) of the 1-mile track jog comparing observed and estimated VO2max (N = 52) resulted in radj = 0.84, SEE = 3.1 ml.kg-1 x min-1. Multiple regression analysis (N = 50) to estimate VO2max from the 1.5-mile run (V:N = 49, radj = 0.90, SEE = 2.8 ml.kg-1 x min-1; CV: N = 47, radj = 0.82, SEE = 3.9 ml.kg-1 x min-1), used elapsed run time, body mass, and gender as independent variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Development of a submaximal treadmill jogging test for fit college-aged individuals.

The purpose of this study was to develop a single-stage submaximal treadmill jogging test for the estimation of maximal oxygen uptake (VO2max). VO2max was measured in 129 relatively fit individuals (males = 84, females = 45), 18-29 yr, using a maximal treadmill protocol (mean +/- SD; VO2max = 48.3 +/- 6.2 ml.kg-1 x min-1, range = 35.6 to 62.3 ml.kg-1 x min-1). The treadmill test required subjects to sustain a comfortable, submaximal jogging pace (4.3-7.5 mph; level grade) until a steady-state heart rate was achieved (approximately 3 min). To help ensure that a submaximal level of exertion was realized for the treadmill jogging test, treadmill speed and exercise HR criteria were established that restricted treadmill speed to < or = 7.5 mph for males and < or = 6.5 mph for females and steady-state exercise HR < or = 180 bpm. Multiple regression analysis (N = 66) to estimate VO2max from the treadmill jogging test yielded the following validation (V) model (r(adj) = 0.84, SEE = 3.2 ml.kg-1 x min-1): VO2max = 54.07 + 7.062 * GENDER (0 = female; 1 = male) - 0.1938 * WEIGHT (kg) + 4.47* SPEED (miles.h-1) - 0.1453 * HEART RATE (bpm). Cross-validation (CV) of the treadmill jogging test comparing observed and estimated VO2max (N = 63) resulted in r(adj) = 0.88, SEE = 3.1 ml.kg-1 x min-1. The results indicate that this submaximal single-stage treadmill jogging test based on multiple linear regression provides a valid and convenient method for estimating VO2max.

Adolescent↗
PubMed1992

Fibrinolytic response during exercise and epinephrine infusion in the same subjects.

To determine whether exercise-induced increases in tissue plasminogen activator (t-PA) were related to plasma epinephrine concentration during exercise, 14 healthy men (aged 24 to 62 years) were studied during epinephrine infusions (10, 25 and 50 ng/kg per min) and graded supine bicycle exercise, beginning at 33 W and increasing in 33-W increments until exhaustion. Plasma epinephrine, active and total t-PA, active plasminogen activator inhibitor type 1 (PAI-1) and t-PA/PAI-1 complex concentrations were measured at each exercise and infusion level. During epinephrine infusion, active and total t-PA levels increased linearly with the plasma epinephrine concentration (respective slopes [+/- SEM] of 0.062 +/- 0.003 and 0.076 +/- 0.003 pmol/ng epinephrine). During exercise, t-PA levels did not increase until plasma epinephrine levels increased, after which both active and total t-PA levels again increased linearly with the plasma epinephrine concentration, but at twice the rate observed with epinephrine infusion (0.131 +/- 0.005 and 0.147 +/- 0.005 pmol/ng, respectively). The t-PA level in blood was directly proportional to the plasma epinephrine concentration during both exercise and epinephrine infusion, suggesting that epinephrine release during exercise stimulates t-PA secretion. In these healthy subjects, active plasminogen activator inhibitor type 1 and t-PA/PAI-1 complex levels were low (41 +/- 11 and 21 +/- 5 pmol/liter, respectively) and did not change significantly during exercise or epinephrine infusion. It is concluded that approximately 50% of the increase in t-PA during exercise is due to stimulated release of t-PA by epinephrine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗