Natural sporting ability and predisposition to cardiovascular disorders.
We tested the hypothesis that people with a natural ability in 'power sports' (a presumed marker for predominance of type 2, glycolytic muscle fibres) might have increased risks of coronary heart disease (CHD) compared to those with a natural ability in 'endurance sports' (as a marker for predominance of type 1, oxidative muscle fibres). We examined subsequent cardiovascular disorders retrospectively in 231 male former soldiers, aged 34-87 years, who had undergone a course in physical training in the Army School of Physical Training, Aldershot, UK, who assessed themselves as having natural ability in either power (n = 107) or endurance (n = 124) sports. The proportion with CHD, defined as angina and/or coronary angioplasty and/or coronary artery bypass graft and/or heart attack was 18.7% in the 'power group' vs. 9.7% in the 'endurance group' (difference: chi 2 = 3.9, p = 0.05). The proportions with CHD and/or risk factors rose to 39.3% in the 'power group' vs. 25.8% in the 'endurance group' (difference: chi 2 = 4.8, p = 0.03). Under logistic regression analysis, compared to the 'endurance group', the 'power group' had 2.2 (95% CI: 1.00-4.63) the risk of developing CHD, and 1.86 (95% confidence interval: 1.06 to 3.25) the risk of developing CHD and/or risk factors. Men with a natural ability in 'power sports' are at increased risk of developing cardiovascular disorders, compared to men with a natural ability in 'endurance sports'. A predominance of type 2, glycolytic muscle fibres, presumably of genetic origin, may predispose to cardiovascular disorders. (+info)
Cardiovascular and metabolic adaptations in horses competing in cross-country events.
The cardiovascular and metabolic response to two cross-country events (CC*: preliminary level and CC*** advanced level) were analysed in 8 male eventing horses (4 Anglo-Hunter and 4 Anglo-Arabian). This study focused on the establishment of the main metabolic pathways involved in the muscle energy resynthesis during the competitions. Heart rate (HR) was recorded throughout the CC events. Jugular venous blood samples were withdrawn before the warm-up period, immediately after the competitions and at 5 and 10 min in the recuperation period. The following haematological parameters were studied: red blood cells (RBC), packed cell volume (PCV), haemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), white blood cells (WBC), and number and percentages of lymphocytes (LYM) and granulocytes and monocytes (GRAN). One fraction of blood was centrifuged and, in plasma, lactate (LA), total plasma protein (TPP) and the rate of LA disappearance were determined. The competitions induced significant increases in RBC, Hb, PCV, MCV and TPP. Plasma LA response exceeded the anaerobic threshold of 4 mmol/l, reaching a maximum level of 13.3 mmol/l. HR ranged from 140 to more than 200 bpm, peaking at 230 bpm, revealing a limitation in the oxygen supply to the working muscles. It was concluded that muscle energy resynthesis during a CC event is provided both through oxidative processes and glycolysis with LA formation. Therefore, both stamina and power exercises are required for eventing horses. (+info)
Should a history section be included on the National Youth Sports Program preparticipation physical examination?
The National Youth Sports Program (NYSP) is an annual event sponsored by the National Collegiate Athletic Association that provides structured sports and enrichment programs to youth of low socioeconomic status. As part of the program, youths undergo a free medical examination that uses a physical examination checklist but does not include a section on medical history. To determine what additional information a medical history would provide, a history form was used in conjunction with the regular preparticipation examination for participants in the 1996 NYSP at the North Carolina Agricultural and Technical State University. The history form provided information such as family history of sudden death, personal history of asthma or bone injury, and whether participants took medications or used corrective lenses. Seventy-nine percent of the completed history forms documented a positive response to at least one question. Of these, only 5% had physical findings on examination. Conversely, 15% of participants had physical findings that were not reported on the history form. Because much of what is discovered by a medical history often is not found on physical examination and because history information can be used to prevent the occurrence of an accident or illness, this study suggests that the use of such a form is beneficial in providing a more comprehensive screening. (+info)
A physiological evaluation of professional soccer players.
The purpose of this study was to evaluate the physiological functions of a professional soccer team in the North American Soccer League (NASL). Eighteen players were evaluated on cardiorespiratory function, endurance performance, body composition, blood chemistry, and motor fitness measures near the end of their competitive season. The following means were observed: age, 26 yrs; height, 176 cm; weight 75.5 kg; resting heart rate, 50 beats/min; maximum heart rate (MHR), 188 beats/min; maximum oxygen intake (VO2 max), 58.4 ml/kg-min-1; maximum ventilation (VEmax BTPS), 154 L/min; body fat, 9.59%; 12-min run, 1.86 miles; and Illinois agility run, 15.6 secs. Results on resting blood pressure, serum lipids, vital capacity, flexibility, upper body strength, and vertical jump tests were comparable to values found for the sedentary population. Comparing the results with previously collected data on professional American Football backs indicated that the soccer players were shorter; lighter in body weight; higher in VO2 max (4 ml/kg-min-1) and body fat (1.8%); and similar in MHR, VE max, and VC. The 12-min run scores were similar to the initial values observed for the 1970 Brazilian World Cup Team. The agility run results were superior to data collected from other groups. Their endurance capabilities, agility, and low percent of body fat clearly differentiate them from the sedentary population and show them to be similar to that of professional American football backs. (+info)
Insulin action on heart and skeletal muscle glucose uptake in weight lifters and endurance athletes.
There are no studies comparing myocardial metabolism between endurance- and resistance-trained athletes. We used 2-deoxy-2-[18F]fluoro-D-glucose and positron emission tomography combined with the euglycemic hyperinsulinemic clamp technique to compare the ability of insulin to stimulate myocardial, skeletal muscle, and whole body glucose uptake between weight lifters (n = 8), endurance athletes (n = 8), and sedentary men (n = 9). Maximal aerobic power (ml. kg- 1. min- 1) was higher in the endurance athletes (71 +/- 2, P < 0.001) than the weight lifters (42 +/- 2) and the sedentary men (42 +/- 2). Skeletal muscle glucose uptake (micromol. kg muscle- 1. min- 1) was enhanced in the endurance athletes (125 +/- 16, P < 0.01) but was similar in weight lifters (59 +/- 12) and sedentary (63 +/- 7) men. The rate of glucose uptake per unit mass of myocardium (micromol. kg- 1. min- 1) was similarly decreased in endurance athletes (544 +/- 50) and weight lifters (651 +/- 45) compared with sedentary men (1,041 +/- 78, P < 0.001 vs. endurance athletes and weight lifters). Both groups of athletes had increased left ventricular mass. Consequently, total left ventricular glucose uptake was comparable in all groups. These data demonstrate that aerobic but not resistance training is associated with enhanced insulin sensitivity in skeletal muscle. Despite this, cardiac changes are remarkably similar in weight lifters and endurance athletes and are characterized by an increase in left ventricular mass and diminished insulin-stimulated glucose uptake per heart mass. (+info)
Incidence and causes of tenosynovitis of the wrist extensors in long distance paddle canoeists.
OBJECTIVES: To investigate the incidence and causes of acute tenosynovitis of the forearm of long distance canoeists. METHOD: A systematic sample of canoeists competing in four canoe marathons were interviewed. The interview included questions about the presence and severity of pain in the forearm and average training distances. Features of the paddles and canoes were determined. RESULTS: An average of 23% of the competitors in each race developed this condition. The incidence was significantly higher in the dominant than the nondominant hand but was unrelated to the type of canoe and the angle of the paddle blades. Canoeists who covered more than 100 km a week for eight weeks preceding the race had a significantly lower incidence of tenosynovitis than those who trained less. Environmental conditions during racing, including fast flowing water, high winds, and choppy waters, and the paddling techniques, especially hyperextension of the wrist during the pushing phase of the stroke, were both related to the incidence of tenosynovitis. CONCLUSION: Tenosynovitis is a common injury in long distance canoeists. The study suggests that development of tenosynovitis is not related to the equipment used, but is probably caused by difficult paddling conditions, in particular uneven surface conditions, which may cause an altered paddling style. However, a number of factors can affect canoeing style. Level of fitness and the ability to balance even a less stable canoe, thereby maintaining optimum paddling style without repeated eccentric loading of the forearm tendons to limit hyperextension of the wrist, would seem to be important. (+info)
Dynamic strength of the quadriceps muscle and sports activity.
The study objectives were to examine the dynamic strength of the quadriceps muscle in athletes, and investigate its association with participation in sport. The study comprised 168 active competitive non-pregnant athletes, aged 14-24 years. The dynamic strength of their quadriceps muscle was measured, and they answered a questionnaire about sports activity and occupation. The dynamic strength of the quadriceps muscle was significantly higher in men than in women, and was positively associated with body weight, years of jogging, years of soccer, and weekly hours of basketball. In conclusion, the dynamic strength of the quadriceps muscle seems to be associated with sports activity. The results suggest sport specific adaptation, which may reflect high levels of running and jumping activity. (+info)
Effects of physical and sporting activities on balance control in elderly people.
OBJECTIVE: Balance disorders increase with aging and raise the risk of accidental falls in the elderly. It has been suggested that the practice of physical and sporting activities (PSA) efficiently counteracts these age related disorders, reducing the risk of falling significantly. METHODS: This study, principally based on a period during which the subjects were engaged in PSA, included 65 healthy subjects, aged over 60, who were living at home. Three series of posturographic tests (static, dynamic with a single and fast upward tilt, and dynamic with slow sinusoidal oscillations) analysing the centre of foot pressure displacements or electromyographic responses were conducted to determine the effects of PSA practice on balance control. RESULTS: The major variables of postural control were best in subjects who had always practised PSA (AA group). Those who did not take part in PSA at all (II group) had the worst postural performances, whatever the test. Subjects having lately begun PSA practice (IA group) had good postural performances, close to those of the AA group, whereas the subjects who had stopped the practice of PSA at an early age (AI group) did not perform as well. Overall, the postural control in the group studied decreased in the order AA > IA > AI > II. CONCLUSIONS: The period during which PSA are practised seems to be of major importance, having a positive bearing on postural control. It seems that recent periods of practice have greater beneficial effects on the subject's postural stability than PSA practice only at an early age. These data are compatible with the fact that PSA are extremely useful for elderly people even if it has not been a lifelong habit. (+info)