Showing papers in "Medicine and Science in Sports and Exercise in 1998"
TL;DR: These data provide a template on which patterns of activity can be classified into intensity levels using the CSA accelerometer, and help to predict energy expenditure at any treadmill speed.
Abstract: Purpose:We established accelerometer count ranges for the Computer Science and Applications, Inc. (CSA) activity monitor corresponding to commonly employed MET categories.Methods:Data were obtained from 50 adults (25 males, 25 females) during treadmill exercise at three different speeds (4.8
3,267 citations
TL;DR: The combination of frequency, intensity, and duration of exercise is found to be the most important factor in determining the intensity and quality of exercise a person receives.
Abstract: SUMMARYACSM Position Stand on The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Adults. Med. Sci. Sports Exerc., Vol. 30, No. 6, pp. 975-991, 1998. The combination of frequency, intensity, and duration of chr
3,095 citations
TL;DR: Gunnar Borg's Perceived Exertion and Pain Scales : Medicine ...
Abstract: Borg's Perceived Exertion and Pain Scales : Medicine ... Gunnar Borg, PhD, introduced the field of perceived exertion during the latter part of the 1950s. Since then, he has won international renown for his work in developing methods for measuring perceived exertion and pain. His method for measuring perceived exertion is the main method used in the field, and his new scale, the Borg CR10 scale, is used for measuring both perceived exertion and pain, and other subjective magnitudes.
3,063 citations
TL;DR: Regular exercise improves health status and contributes to an increase in life expectancy, and involvement in regular exercise can also provide a number of psychological benefits related to preserved cognitive function, alleviation of depression symptoms.
Abstract: SUMMARYACSM Position Stand on Exercise and Physical Activity for Older Adults. Med. Sci. Sports. Exerc., Vol. 30. No. 6, pp. 992-1008, 1998. By the year 2030, the number of individuals 65 yr and over will reach 70 million in the United States alone; persons 85 yr and older will be the fastest gr
1,641 citations
TL;DR: It was observed that a high percentage of illnesses could be accounted for when individual athletes exceeded individually identifiable training thresholds, mostly related to the strain of training.
Abstract: Purpose: Overtraining is primarily related to sustained high load training, often coupled with other stressors. Studies in animal models have suggested that unremittingly heavy training (monotonous training) may increase the likelihood of developing overtraining syndrome. The purpose of this study was to extend our preliminary observations by relating the incidence of illnesses and minor injuries to various indices of training. Methods: We report observations of the relationship of banal illnesses (a frequently cited marker of overtraining syndrome) to training load and training monotony in experienced athletes (N = 25). Athletes recorded their training using a method that integrates the exercise session RPE and the duration of the training session. Illnesses were noted and correlated with indices of training load (rolling 6 wk average), monotony (daily mean/standard deviation), and strain (load * monotony). Results: It was observed that a high percentage of illnesses could be accounted for when individual athletes exceeded individually identifiable training thresholds, mostly related to the strain of training. Conclusions: These results suggest that simple methods of monitoring the characteristics of training may allow the athlete to achieve the goals of training while minimizing undesired training outcomes.
1,067 citations
TL;DR: In this paper, the validity of the CSA activity monitor as a measure of children's physical activity using energy expenditure (EE) as a criterion measure was evaluated using three 5-min treadmill bouts at 3, 4, and 6 mph.
Abstract: Purpose:The purpose of this study was to evaluate the validity of the CSA activity monitor as a measure of children's physical activity using energy expenditure(EE) as a criterion measure.Methods:Thirty subjects aged 10 to 14 performed three 5-min treadmill bouts at 3, 4, and 6 mph, respecti
821 citations
TL;DR: This study quantified knee forces and muscle activity in CKCE and OKCE to help in choosing appropriate exercises for rehabilitation and training.
Abstract: Purpose:Although closed (CKCE) and open (OKCE) kinetic chain exercises are used in athletic training and clinical environments, few studies have compared knee joint biomechanics while these exercises are performed dynamically. The purpose of this study was to quantify knee forces and muscle
596 citations
TL;DR: It is concluded that for soccer players, maximal oxygen uptake should be expressed in relation to body mass raised to the power of 0.75 and maximal strength in relationTo evaluate maximal aerobic capacity when running and strength capacity among players with different body mass.
Abstract: Purpose:The major purpose of the present study was to examine whether there exists a relationship between preseasonal physiological tests and performance results in the soccer league. Further, it investigated maximal oxygen uptake and maximal strength in proportion to body mass for soccer pl
494 citations
TL;DR: The hypothesis of maternal inheritance, with the father's contribution being environmental, was found to fit the data with estimates of maternal heritability, potentially associated with mitochondrial inheritance, reaching about 30%.
Abstract: This study investigates the familial resemblance of maximal oxygen uptake (VO2max) based on data from 86 nuclear families of Caucasian descent participating in the HERITAGE Family Study. In the current study, VO2max was measured twice on a cycle ergometer in 429 sedentary individuals (170 parents and 259 of their offspring), aged between 16 and 65 yr. The VO2max was adjusted by regression procedures for the effects of 1) age and sex; 2) age, sex, and body mass; and 3) age, sex, body mass, fat mass, and fat-free mass, as determined by underwater weighing. Evidence for significant familial resemblance was observed for each of the three VO2max phenotypes. Spouse, sibling, and parent-offspring correlations were significant, suggesting that both genetic and environmental factors contribute to the familial resemblance for VO2max. Maximal heritability estimates were at least 50%, a value inflated to an undetermined degree by nongenetic factors. The hypothesis of maternal inheritance, with the father's contribution being environmental, was also found to fit the data with estimates of maternal heritability, potentially associated in part with mitochondrial inheritance, reaching about 30%. These results suggest that genetic and nongenetic factors as well as maternal influences contribute to the familial aggregation of VO2max in sedentary individuals.
460 citations
TL;DR: It is concluded that in COPD, the vastus lateralis muscle is characterized by a marked decrease in Type I fiber proportion, an increase in Type IIb Fiber proportion, a decrease inType I, IIa, and IIab fiber CSA and by a relatively preserved capillarization.
Abstract: Histochemical and morphological characteristics of the vastus lateralis muscle in patients with chronic obstructive pulmonary disease. Med. Sci. Sports Exerc., Vol. 30, No. 10, pp. 1467-1474, 1998.Purpose and Methods:In this study, we examined the fiber-type proportions, cross-sectional area
460 citations
TL;DR: The addition of creatine to the glucose/taurine/electrolyte supplement promoted greater gains in fat/bone-free mass, isotonic lifting volume, and sprint performance during intense resistance/agility training.
Abstract: Purpose:To determine the effects of 28 d of creatine supplementation during training on body composition, strength, sprint performance, and hematological profiles.Methods:In a double-blind and randomized manner, 25 NCAA division IA football players were matched-paired and assigned to supplem
TL;DR: It was concluded that much of the pathology and etiology of tendonitis remains unclear and the possibility must be considered that current treatment methods may not significantly affect the natural history.
Abstract: Tendonitis is a common diagnosis in sports medicine. The traditional view of tendonitis is a tendon injury resulting from repetitive mechanical load with a subsequent inflammatory response. The English literature from 1966 to the present on the etiology, diagnosis, and treatment of tendonitis was evaluated. There is some scientific support in the literature for the diagnosis of tenosynovitis and tendinosis as a pathologic entity. Actual inflammation of tendon tissue consistent with tendonitis has not been seen clearly in patho-anatomic studies. Conclusive evidence confirming that repetitive mechanical load is a major etiologic factor could not be found. Similarly, strength deficits, inflexibility, and improper equipment have not been studied in a controlled prospective manner. Other factors such as age and tendon vascularity have been consistently correlated with these injuries although their overall importance remains difficult to assess. There are no controlled studies on treatment through physical therapy aimed at flexibility and/or strengthening. Treatment with anti-inflammatory drugs has been studied extensively. However, only nine of 32 studies are prospective and placebo controlled. Some pain relief was found in five of the nine controlled studies, but healing of the tendon problem was not studied in these short follow-up studies. Twenty-three studies on steroid injections were found. Eight were prospective and placebo controlled studies, with three showing beneficial effects of the injection at follow-up. It was concluded that much of the pathology and etiology of tendonitis remains unclear. The possibility must be considered that current treatment methods may not significantly affect the natural history.
TL;DR: Evidence for the existence of central biological control in the population, offers a rationale for its function, and suggests implications for preventive health strategies resulting from a biological contribution to habitual activity levels are examined.
Abstract: Successful efforts to improve levels of physical activity in the population are contingent upon an accurate understanding of the determinants of habitual activity. While most research has focused on psychosocial and environmental influences, the potential effect of intrinsic biological control on regular activity has received little attention. This review examines evidence for the existence of such central control, offers a rationale for its function, and suggests implications for preventive health strategies resulting from a biological contribution to habitual activity levels.
TL;DR: The results suggest the telemetry pill system provides a valid measurement of core temperature during conditions of decreasing as well as increasing body temperature and during steady state.
Abstract: Purpose:This study compared the agreement between core temperature measurements obtained using an ingestible temperature pill telemetry system (Tpill) with those obtained from rectal (Tre) and esophageal (Tes) thermocouples under conditions of increasing and decreasing body temperatureMetho
TL;DR: The results indicate that a 12-month Tai Chi Chuan program is effective for improving health fitness of the elderly.
Abstract: Purpose:The objective of this study was to evaluate the effect of Tai Chi Chuan(TCC) on health fitness in older individuals.Methods:Thirty-eight community-dwelling persons aged 58 to 70 yr completed this study. The TCC group included 9 men and 11 women; the control group included 9 men and 9
TL;DR: The findings support anecdotal evidence that fatigued individuals are at increased risk of injury because of loss of balance and avoidance of fatigue and preconditioning may prevent injury.
Abstract: Effect of lower extremity muscular fatigue on motor control performance. Med. Sci. Sports Exerc., Vol. 30, No. 12, pp. 1703-1707, 1998.Purpose:The purpose of this study was to determine whether lower extremity fatigue affects the ability of an individual to balance on an unstable platform.Me
TL;DR: In this paper, the foot-ground impact experienced during running produces a shock wave that is transmitted through the human skeletal system, which is attenuated by deformation of the ground/shoe as well as biological tissues in the body.
Abstract: Purpose:The foot-ground impact experienced during running produces a shock wave that is transmitted through the human skeletal system. This shock wave is attenuated by deformation of the ground/shoe as well as deformation of biological tissues in the body. The goal of this study was to inves
TL;DR: Consideration of deep muscle activity, provided in this report, is important for choosing the best abdominal exercise, together with activation profiles during lifting, during twisting, and during hip rotation.
Abstract: Purpose:Since most previous reports of EMG activation profiles from psoas and the abdominal wall have been qualitative, the objective of this work was to document myoelectric activity from these deep muscles. This knowledge is required to assist in choosing specific training exercises and fo
TL;DR: This is the first questionnaire to measure lifetime physical activity by collecting data on each type of physical activity separately over lifetime and by measuring frequency, intensity, and duration of each activity.
Abstract: Objective:To develop and test the intra-rater reliability of an interview-administered questionnaire that assesses lifetime patterns of total physical activity including occupational, household, and exercise/sports activities.Methods:The questionnaire was developed and pretested using cognit
TL;DR: Data indicate that carbohydrate versus placebo ingestion (4 mL x kg(-1) carbohydrate or placebo every 15 min of the 2.5-h exercise bout) is associated with higher plasma glucose levels, an attenuated cortisol response, and a diminished pro- and anti-inflammatory cytokine response.
Abstract: Objective and Methods:This randomized, double-blind, placebo-controlled study was designed to determine the influence of exercise mode and 6% carbohydrate (C) versus placebo (P) beverage ingestion, on blood cell counts, plasma glucose, hormone, and inflammatory cytokine responses (five total
TL;DR: It is indicated that high intensity resistance exercise increases free radical production and that vitamin E supplementation may decrease muscle membrane disruption.
Abstract: The purposes of this investigation were to see whether free radical production changed with high intensity resistance exercise and, secondly, to see whether vitamin E supplementation would have any effect on free radical formation or variables associated with muscle membrane disruption. Twel
TL;DR: To achieve long-standing control of overweight, one should combine changes in eating and activity patterns, using behavior modification techniques, and the onus is also on society to reduce incentives for a sedentary lifestyle and over-consumption of food.
Abstract: Almost one-quarter of U.S. children are now obese, a dramatic increase of over 20% in the past decade. It is intriguing that the increase in prevalence has been occurring while overall fat consumption has been declining. Body mass and composition are influenced by genetic factors, but the actual heritability of juvenile obesity is not known. A low physical activity (PA) is characteristic of obese children and adolescents, and it may be one cause of juvenile obesity. There is little evidence, however, that overall energy expenditure is low among the obese. There is a strong association between the prevalence of obesity and the extent of TV viewing. Enhanced PA can reduce body fat and blood pressure and improve lipoprotein profile in obese individuals. Its effect on body composition, however, is slower than with low-calorie diets. The three main dietary approaches are: protein sparing modified fast, balanced hypocaloric diets, and comprehensive behavioral lifestyle programs. To achieve long-standing control of overweight, one should combine changes in eating and activity patterns, using behavior modification techniques. However, the onus is also on society to reduce incentives for a sedentary lifestyle and over-consumption of food. To address the key issues related to childhood weight management, the American College of Sports Medicine convened a Scientific Roundtable in Indianapolis.
TL;DR: It is concluded that an aerobic exercise program of precisely defined intensity, duration, and frequency can be prescribed as therapy for primary fatigue in cancer patients.
Abstract: Purpose:Fatigue and impairment of physical performance are common and severe problems of cancer patients. We describe the effect of an aerobic exercise program designed for cancer patients suffering from these symptoms.Methods:Five cancer patients (4 female, 1 male, age 18 to 55), participat
TL;DR: It was concluded that plasma lactate parameters and W(peak) provide better indices of endurance performance than peak VO(2) and that, of the six descriptors of lactate increase measured in this study, LT(D) is most strongly related to 1-h cycling performance in trained, female cyclists.
Abstract: The relationship between plasma lactate parameters, Wpeak and 1-h cycling performance in women.Med. Sci. Sports Exerc., Vol. 30, No. 8, pp. 1270-1275, 1998.
Purpose: The relationship between six descriptors of lactate increase, peak V·O2, Wpeak, and 1-h cycling performance were compared in 24 trained, female cyclists (peak V·O2= 48.11 ± 6.32 mL·kg-1·min-1).
Methods: The six descriptors of lactate increase were: 1) lactate threshold (LT; the power output at which plasma lactate concentration begins to increase above the resting level during an incremental exercise test), 2) LT1 (the power output at which plasma lactate increases by 1 mM or more), 3) LTD (the lactate threshold calculated by the D-max method), 4) LTMOD (the lactate threshold calculated by a modified D-max method), 5) L4 (the power output at which plasma lactate reaches a concentration of 4 mmol·L-1), and 6) LTLOG (the power output at which plasma lactate concentration begins to increase when the log([La-]) is plotted against the log (power output)). Subjects first completed a peak V·O2 test on a cycle ergometer. Finger-tip capillary blood was sampled within 30 s of the end of each 3-min stage for analysis of plasma lactate. Endurance performance was assessed 7 d later using a 1-h cycle test (OHT) in which subjects were directed to achieve the highest possible average power output.
Results: The mean power output (W) for the OHT (± SD) was 183.01 ± 18.88, and for each lactate variable was: LT (138.54 ± 46.61), LT1 (179.17 ± 27.25), LTLOG (143.97 ± 45.74), L4 (198.09 ± 33.84), LTD(178.79 ± 24.07), LTMOD (212.28 ± 31.75). Average power output during the OHT was more strongly correlated with all plasma lactate parameters (0.61< r < 0.84) and Wpeak (r = 0.81) than with peak V·O2 (r = 0.55). The six lactate parameters were strongly correlated with each other (0.54< r < 0.91) and of the six lactate parameters, LTD correlated best with endurance performance (r = 0.84).
Conclusions: It was concluded that plasma lactate parameters and Wpeak provide better indices of endurance performance than peak V·O2 and that, of the six descriptors of lactate increase measured in this study, LTD is most strongly related to 1-h cycling performance in trained, female cyclists.
TL;DR: Short bouts of brisk walking resulted in similar improvements in fitness and were at least as effective in decreasing body fatness as long bouts of the same total duration.
Abstract: This study compared the effects of short and long bouts of brisk walking in sedentary women. Forty seven women aged 44.4 +/- 6.2 yr (mean +/- SD) were randomly assigned to either three 10-min walks per day (short bouts), one 30-min walk per day (long bouts) or no training (control). Brisk walking was done on 5 d x wk(-1), at 70 to 80% of maximal heart rate, typically at speeds between 1.6 and 1.8 m x s(-1) (3.5 and 4.0 mph), for 10 wk. Subjects agreed not to make changes to their diet. Twelve short-bout walkers, 12 long-bout walkers, and 10 controls completed the study. Relative to controls, VO2max (short-bout, +2.3 +/- 0.1 mL x kg(-1) x min(-1); long-bout, +2.4 +/- 0.1 mL x kg(-1) x min(-1); controls, -0.5 +/- 0.1 mL x kg(-1) x min[-1]) and the VO2 at a blood lactate concentration of 2 mmol x L(-1) increased in walkers (both P < 0.05), with no difference in response between walking groups. Neither heart rate during standard, submaximal exercise nor resting systolic blood pressure changed in a different way in walkers and controls. The sum of four skinfold thicknesses decreased in both walking groups (P < 0.05) but body mass (short-bout, -1.7 +/- 1.7 kg; long-bout, -0.9 +/- 2.0 kg; controls, +0.6 +/- 0.7 kg) and waist circumference decreased significantly only in short-bout walkers. Changes in anthropometric variables did not differ between short- and long-bout walkers. Thus short bouts of brisk walking resulted in similar improvements in fitness and were at least as effective in decreasing body fatness as long bouts of the same total duration.
TL;DR: Results indicated that after reconstruction surgery and accelerated rehabilitation for ACL injury, humans walk with normal kinematic patterns but continue to use altered joint torque and power patterns.
Abstract: DEVITA. P.. T. HORTOBAGYI, and I. BARRIER. Gait biomechanics are not normal after anterior cruciate ligament reconstruction and accelerated rehabilitation. Med. Sci. Sports Exerc.. Vol. 30, No. 10. pp. 1481-1488. 1998. Purpose: Accelerated rehabilitation for anterior cruciate ligament (ACL) injury and reconstruction surgery is designed to return injured people to athletic activities in approximately 6 months. The small amount of empirical data on this population suggests, however, that the torque at the knee joint may not return until 29, months after surgery during walking and even longer during running. Although the rehabilitation has ended and individuals have returned to preinjury activities. gait mechanics appear to be abnormal at the end of accelerated programs. The purpose of this study was to compare lower extremity joint kinematics. kinetics, and energetics between individuals having undergone ACL reconstruction and accelerated rehabilitation and healthy individuals. Methods: Eight ACL-injured and 22 healthy subjects were tested. Injured subjects were tested 3 wk and 6 months (the end of rehabilitation) rfter surgery. Ground reaction force and kinematic data were combined with inverse dynamics to predict snginal plane joint toques and powers from which angular impulse and work were derived. Results: The difference in all kinematic variables between the two tests for the ACL group avenged 38% (all P < 0.05 ). The kinematics were not. different between the ACL group after rehabilitation and healthy subjects. Angular impulses and work averaged 100% difference for all joints (all P < 0.05) between tests for the ACL group. Afrer rehabilitation. the differences between injured and healthy groups in angular impulse and work at both the hip and knee remained luge and averaged 52% (all P < 0.05). Conclusions: Results indicated that after reconstruction surgery and accelerated rehabilitation for ACL injury. humans walk with
TL;DR: Urine osmolality and conductivity as indices of hydration status in athletes in the heat were used in this paper. But, they did not consider the effect of temperature on performance.
Abstract: Urine osmolality and conductivity as indices of hydration status in athletes in the heat. Med. Sci. Sports Exerc., Vol. 30, No. 11, pp. 1598-1602, 1998.Purpose:The purpose of this study was to determine a quick and easy method for assessment of day-to-day hydration status in athletes in the
TL;DR: To impact the ball with the medial aspect of the foot in the pass kick, the player orients the pelvis, the right leg, and the foot more toward the right and introduces a medial component of foot velocity.
Abstract: Comparison of the kinematics of the full-instep and pass kicks in soccer. Med. Sci. Sports Exerc., Vol. 30, No. 6, pp. 917-927, 1998.Purpose:The goal of this study was to gain a better understanding of the mechanics of the inside-of-the-foot passing shot used in soccer ("pass kick").Meth
TL;DR: Functional alterations of pituitary-adrenal axis and sympathetic system can explain persistent performance incompetence in affected athletes.
Abstract: Purpose: The parasympathetic, Addison type, overtraining syndrome represents the dominant modern type of this syndrome. Beside additional mechanisms, an autonomic or neuroendocrine imbalance is hypothesized as underlying. Methods/Results: Several findings support this thesis. During heavy endurance training or overreaching periods, the majority of findings give evidence of a reduced adrenal responsiveness to ACTH. This is compensated by an increased pituitary ACTH release. In an early stage of the overtraining syndrome, despite increased pituitary ACTH release, the decreased adrenal responsiveness is no longer compensated. The cortisol response decreases. In an advanced stage of overtraining syndrome, the pituitary ACTH release also decreases. In this stage, there is additionally evidence for decreased intrinsic sympathetic activity and sensitivity of target organs to catecholamines. This is indicated by decreased catecholamine excretion during night rest, decreased β-adrenore-ceptor density, decreased β -adrenoreceptor-mediated responses, and increased resting plasma norepinephrine levels and responses to exercise. However, this complete pattern is only observed subsequent to high-volume endurance overtraining at high caloric demands. Conclusion: The described functional alterations of pituitary-adrenal axis and sympathetic system can explain persistent performance incompetence in affected athletes.
TL;DR: The hypothesis of a hypothalamo-pituitary dysregulation during OT expressed by an impaired response of pituitary hormones to exhaustive short-endurance exercise is confirmed.
Abstract: The aim of the present prospective longitudinal study was to investigate the hormonal response in overtrained athletes at rest and during exercise consisting of a short-term exhaustive endurance test on a cycle ergometer at an intensity 10% above the individual anaerobic threshold. Over a period of 19+/-1 months, 17 male endurance athletes (cyclists and triathletes; age 23.4+/-1.6 yr; VO2max. 61.2+/-1.8 mL x min(-1) x kg(-1); means+/-SEM) were examined five times on two separate days under standardized conditions. Short-term overtraining states (OT, N=15) were primarily induced by an increase of frequency of high-intensive bouts of exercise or competitions without increase of the total amount of training. OT was compared with normal training states intraindividually (NS, N=62). During OT, the time to exhaustion of the exercise test was significantly decreased by 27% on average. At rest and during exercise, the concentrations in plasma and the nocturnal excretion in urine of free epinephrine and norepinephrine were not significantly changed during OT. At physical rest, the concentrations of (free) testosterone, cortisol, luteinizing hormone, follicle-stimulating hormone, adrenocorticotropic hormone, growth hormone, and insulin during OT were comparable with those during NS. A significantly (P < 0.025) lower maximal exercise-induced increase of the adrenocorticotropic hormone and growth hormone, as well as a trend for a decrease of cortisol (P=0.060) and insulin (P=0.036), was measured. The response of free catecholamines as well as the ergometric performance of an all-out 30-s test was unchanged. Serum urea, uric acid, ferritin, and activity of creatine kinase showed no differences between conditions. In conclusion, the results confirm the hypothesis of a hypothalamo-pituitary dysregulation during OT expressed by an impaired response of pituitary hormones to exhaustive short-endurance exercise.