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Biomedical subjects

R Bulbulian

Publications and source records attributed to R Bulbulian.

28 records · Page 2Linked to original sources
PubMed1986

Anaerobic contribution to distance running performance of trained cross-country athletes.

Recent reports have suggested that running economy (RE) defined as oxygen consumption at standardized treadmill speeds may be an important determinant for successful distance running performance. The purpose of this study was to examine the additional role, if any, played by anaerobic factors in distance running performance. Highly trained male cross-country runners (N = 12) were administered a battery of standardized aerobic and anaerobic laboratory evaluations. Maximal oxygen uptake (VO2max) and RE (ml X kg-1) were measured using open circuit spirometry during treadmill exercise. RE was measured at 241 and 295 m X min-1, and ventilatory threshold (Tvent) was determined and verified using a number of non-invasive ventilatory measures (VE, VE/VO2, VE/VCO2, VCO2, FECO2). Anaerobic measures included the Margaria power test and the Monod critical power test to determine anaerobic work capacity (AWC). The data were subjected to a SAS-STEPWISE analysis which combines stepwise addition and backward elimination and were used to predict performance time in a 8.05-km (5-mile) cross-country race in which all the runners participated. The subjects averaged 26.21 min for the 8.05 km run, with 72.1 ml X kg-1 X min-1 for the VO2max with a Tvent at 60.4 ml X kg-1 X min-1 (84% VO2max). AWC (Monod) was 17400 Joules with a range of 8,000-28,400 Joules. The STEPWISE procedure reveals that AWC contributes significantly (P less than 0.003) to a 3 variable model predicting race performance (R2 = 0.76, P less than 0.01). AWC accounts for 58% of total shared variance with VO2max and an indirect measure of Tvent accounting for the remaining 17%.(ABSTRACT TRUNCATED AT 250 WORDS)

Exercise Test↗
PubMed1985

Effect of exercise duration on feed intake and body composition of Swiss albino mice.

The purpose of this study was to examine the effects of daily exercise of varying duration on the body composition, weight, and feed intake of mature Swiss albino mice. Fifty-four male mice were equally divided into a control group and five exercise groups (n = 9) performing 20, 40, 60, 120, and 240 min of daily exercise on a treadmill (7.2 m/min). Feed intake and body weight were measured weekly for 10 wk. At the completion of the study the mice were killed and the animal carcasses were chemically analyzed for fat, dry matter, and protein content. The results of this study demonstrate no differences in the body weight among groups (P less than 0.97) with all groups gaining 4.5-5.8 g during the 10-wk period. However, fat content decreased significantly from 15.7% in the control to 12.0% in the 120- and 240-min exercise groups (P less than 0.05). In contrast, protein content showed an insignificant rising trend from 13.0 to 14.6% with increasing duration of exercise. Feed intake showed a nonsignificant drop during the 20-min exercise treatment and remained unchanged among groups. These data show a slight but variable appetite-suppressing effect of light exercise in mice accompanied by favorable body composition changes even in the absence of differences in body weight. These findings suggest the mouse to be an acceptable experimental model for body composition and exercise studies.

Adipose Tissue↗
PubMed1984

The influence of somatotype on anthropometric prediction of body composition in young women.

The influence of somatotype on the validity of anthropometric prediction of body density (Db) in young women (N = 92) was investigated. Three groups of predominantly endomorph (N = 27), mesomorph (N = 35), and ectomorph (N = 30) women were identified by the Heath-Carter and Sheldon somatotyping methods. Discriminant analysis revealed a 100% accuracy in somatotype group determination. Thirteen diameters, 26 girths, and 8 skinfolds were measured and used in a STEPWISE regression analysis to derive somatotype-specific regression equations to predict body density. Combining all the measures provided very good prediction accuracy in all three groups with multiple correlation coefficients (R) of 0.98, 0.90, and 0.90, and the standard error of estimate (SEE) of 0.003, 0.005, and 0.005 for Db (gm X cc-1) in the endomorphs, mesomorphs, and ectomorphs, respectively. A cross-validation study confirmed the accuracy of the somatotype-specific regression equations and demonstrated an inherent weakness in using some generalized equations on specific somatotypes. The use of non-somatotype-specific equations resulted in mean Db prediction errors ranging from -0.018 to +0.023 gm X cc-1 (8.5 to -10.7% Fat). Although all equations tested demonstrated specific weaknesses in one or more of the somatotype groups when predicting Db, the Jackson et al. (1980) equation performed better than most of the non-somatotype-specific prediction equations. These findings suggest that the anthropometric estimation of Db may not be sample specific in the same manner as had been previously thought and that greater accuracy may be achieved by using regression equations which have been generated on a previously somatotyped population sample.

Adolescent↗
PubMed1983

The effect of NH4Cl induced chronic metabolic acidosis on work capacity in man.

Eleven male and female subjects were randomly assigned to two treatment groups. One experimental ammonium chloride (NH4Cl) group (n = 6) and one calcium carbonate (CaCO3) placebo control group (n = 5) received treatment lasting 10 days. No significant changes were observed in several ventilatory parameters (VE, VE/V2, VE/VO2) during submaximal or maximal exercise. Heart rates and performance times were similarly unaltered. Changes were observed in oxygen consumption (VO2) and plasma lactates (HLa) during submaximal exercise at 40% maximal power output (approximately 48% VO2max). VO2 decreased from 1.12 l X min-1 to 1.04 l X min-1 (t = 2.87, p less than 0.05) and HLa were depressed from 2.3 to 1.9 mM X 1(-1) (t = 3.92, p less than 0.02). HLa and VO2max were not changed during an incremental VO2max test. The evidence suggests that under conditions of experimental renalcompensated, chronic metabolic acidoses (CMA), there are no significant changes in most cardiopulmonary parameters measured during maximal and submaximal exercise. It appears that the decrements in performance reported by previous investigators may be due to pH changes of acidosis rather than accompanying compensatory changes of acid-base control.

Acidosis↗
PubMed1982

Comparison of oxygen kinetics in young and old subjects.

Five older men (aged 60-69 yr) and five young men (aged 21-29 yr) with approximately equal levels of age-corrected VO2 max were compared with respect to oxygen kinetics at equal absolute workloads (100 watts) and at equal relative workloads (45% VO2 max) on a cycle ergometer. At 45% VO2 max, half times for VO2 response to instantaneous transition from unloaded pedalling were 30.0 s and 27.4 s for old and young respectively (t = 0.260, p less than 0.80). No significant differences were found in the VE response and by inference none existed in O2 extraction. Mean half times for heart rate responses at a workload of 100 W were 24.2 s and 20.6 s for old and young groups respectively (t = 0.722, p less than 0.49). Mechanical efficiency estimated from steady state data at 100 W was 19.8% and 20.5% for old and young groups respectively (t = 0.574). The close similarity in responses to submaximal work in old and young subjects of equivalent fitness suggests caution in the interpretation of agewise decrements observed in physiological variables which may be sensitive to physical fitness status.

Age Factors↗
PubMedDate not supplied

The effect of activity history and current activity on static and dynamic postural balance in older adults.

The purpose of this study was to investigate the effects of former athleticism and current activity status on static and dynamic postural balance in older adults. Fifty-six subjects participated in four study groups including former athletes, currently active (AA; n = 15; 69.1+/-4.4 years.; 77.8+/-9.8 kg), former athletes, currently inactive (AI; n = 12; 66.7 years.; 87.2+/-15.1 kg), controls currently active (CA; n = 14; 68.6 +/- 4.5 years.; 73.9+/-15 kg), and controls currently inactive (CI; n = 15; 72.8+/-4.8 years; 81.1+/-14.8). All subjects were tested for height, weight, flexibility, thigh circumference, and static (sharpened Romberg/unipedal stance), and dynamic (step length and width) balance tests. The sharpened Romberg (eyes open) test showed that AA (60.0+/-0 s) and CA (59.4+/- 0.5 s) balanced significantly longer than AI (41.5+/-7.2 s), and CI (41.8+/-6.1 s) (p<0.05). The unipedal (eyes open) test balance scores for AA, CA, AI, and CI were respectively 40.0+/-4.5, 55.1+/- 3.4, 33.0+/-7.1, and 27.5+/-6.1 s, with CA significantly better than CI (p<0.05). In dynamic balance AA and CA (746.1+/-28.0 and 724.6+/-24.3 mm) showed significantly longer step lengths (p<0.05) than CI (643.7+/-26.5 mm). The eyes closed test results for relative group comparisons were similar. Overall, two-way analysis of variance showed a significant activity main effect for all dependent variables measured (p<0.05). The results indicated that current activity status plays a key role on balance performance in older adults. Furthermore, former athletic activity history provides no protection for the age related onset of postural imbalance.

Aged↗
PubMedDate not supplied

The short golf backswing: effects on performance and spinal health implications.

BACKGROUND: Full recoil golf swings have been implicated in back pain and injury in golfers. Evidence suggests that a restricted backswing may reduce the potential for injury without compromising performance. OBJECTIVE: To examine both golf swing performance and selected muscular actions of the trunk and shoulder during a full recoil swing as compared with a modified short backswing. METHODS: Electromyographic (EMG) recordings were taken bilaterally from the lumbar, external oblique, latissimus dorsi, and right pectoral muscles in 7 golfers during a full recoil swing and a modified short backswing. High-speed videotape was used to measure back swing angle reduction. Clubhead velocity (CHV) and ball-contact accuracy were quantified by using a swing speed indicator and clubface contact tape, respectively. RESULTS: Shortening of the backswing by 46.5 degrees +/- 24.7 degrees had no effect on stroke accuracy as measured by mean deviation from the target spot on the club (19.0 +/- 7.8 mm vs 19.3 +/- 9.2 mm). CHV was not significantly reduced (33.9 +/- 2.5 m/s vs 31.2 +/- 2.2 m/s). However, EMG root-mean-square was decreased 19% in the right oblique muscle from 750 to 250 ms before impact (P < .05). During the acceleration phase, activation of left lumbar muscle decreased by 12%, whereas activation of right latissimus muscle increased by 21%. Although left lumbar muscle activity during the follow-through increased 14%, there was a substantial (17%) but nonsignificant decrease of activation of trunk muscles (P = .11). There was a general trend toward an increased activation of the shoulder musculature from 250 ms before impact to 500 ms after impact. CONCLUSION: These data support the idea that short backswings in golf may reduce trunk muscle activation and possibly reduce back injury and pain without negatively impacting swing accuracy or CHV. However, the short swing increases shoulder muscle activation and may, in turn, promote risk for shoulder injury.

Adult↗