ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00410.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Anaerobic capacity may be defined as the maximal amount of ATP formed by the anaerobic processes during a single bout of maximal exercise. While several methods have been presented to measure a person's anaerobic capacity, none have become universally accepted. The muscle biopsy technique provides information on the anaerobic energy release from direct measures of ATP and CP breakdown and muscle lactate concentrations. As a practical measure of anaerobic capacity, the method may be limited, as it is an invasive, skilled technique. Furthermore, it has the limitation of measuring relative changes in concentrations, not amounts, such that the anaerobic contribution is estimated from estimates of the active muscle mass involvement. Measurement of lactate in blood after exhaustive exercise has frequently been used, but several factors suggest that, while it provides an indication of the extent of anaerobic glycolysis, it cannot be used as a quantitative measure of the anaerobic energy yield. The mean power during an all‐out effort on a bicycle ergometer has also been assumed to be a measure of anaerobic capacity, yet it provides only an indication of the ability to maintain high power outputs. Concerns over the duration of the test, the protocol and type of ergometer used and the contribution of the aerobic energy system to the energy supply also limit its validity as a measure of anaerobic capacity. The oxygen debt, defined as the recovery oxygen uptake above resting metabolic rates, has been discredited as a valid and reliable measure of the anaerobic capacity, as it is generally acknowledged that mechanisms other than the metabolism of lactate also contribute to the post‐exercise oxygen uptake. The recent work of Medbø et al. in re‐examining the issue of oxygen deficit has created considerable interest in its use as a measure of anaerobic capacity. The measurement of oxygen deficit directly depends on the accurate assessment of the energy cost of the work completed. This is not difficult during submaximal exercise, as the steady‐state oxygen uptake represents the energy costs. During exhaustive supramaximal exercise, the validity of the maximal accumulated oxygen deficit as a measure of the anaerobic capacity has been questioned, as the energy cost is estimated and not measured, either by assuming a given mechanical efficiency or by extrapolating the submaximal relationship between work intensity and oxygen uptake to supramaximal levels. Despite these theoretical objections, the maximal accumuiated oxygen deficit method remains a promising measure of the anaerobic capacity, as it provides a non‐invasive means of quantifying the anaerobic energy release during exhaustiv

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00411.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The purpose of this study was to determine the resting values of growth hormone (GH) and testosterone (T) within prepubertal, pubertal and adolescence ages and to compare the effects of physical training in each age, in 2 groups. The exercise group (A) consisted of 10 ten‐year‐old boys, 10 thirteen‐year‐old boys and 9 sixteen‐year‐old boys. The control group (B) consisted of approximately the same number of subjects of the same ages. Group A, in addition to the school activity, trained with intervals (3 months, 50 mid/day, 3 days/week). at high intensity (80–85% of max) and at light intensity (30–40% of max). Group B participated only in the school physical education program 2–3 times/week. Venous blood samples were taken at rest by intravenous catheter before and after training. Levels of GH and T in blood serum was determined by radioimmunoassay. Before training, the levels of T differed between the 3 ages, but there were no significant differences in GH (group A and B). After training, the levels of GH and T in group A were significantly higher in the 13‐year‐old boys and in the 16‐year‐old boys, but were unchanged in the 10‐year‐old boys. In group B the levels of GH and T were unchanged in all 3 ages. The conclusion is that neither high nor mild intensity training can change the levels of GH and T in prepubertal boys. However, high intensity training can be a stimulus for increasing GH and T lev

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00412.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The effect of liniment applied by massage or stick on skin and calf blood flow was studied in 12 subjects. The blood flow was recorded with laser Doppler flowmetry with skin probe and strain gauge plethysmography. A massage liniment used to lower the friction that is not supposed to have any therapeutic effect (Frisco) was massaged into the right lower leg for 10 min and the registration was performed for 60 min. Then the liniment studied, Tiger Balm was massaged into the left lower leg and another registration was carried out. This procedure was performed a second time and the liniments were applied with a stick and wiped off after 10 min. Liniments with massage resulted in an increase in both skin and calf blood flow. The effect was greater and longer lasting when using Tiger Balm. When the liniments were applied with a stick, a decrease in skin and calf blood flow was noted when using Frisco. Tiger Balm caused a slight increase in the skin blood flow but had no influence on the calf blood flow.

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00413.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The reported high use of anti‐asthmatic drugs in cross‐country skiers prompted a study to assess the prevalence of self‐reported asthma, asthma‐associated symptoms and the use of anti‐asthmatic medication among cross‐country skiers. A self‐administered questionnaire based on the Medical Research Council questionnaire was answered by cross‐country skiers in the Swedish national ski team, in upper secondary school ski‐classes and in the Swedish army (n=305). Controls (n=141) were pupils from regular classes in the same upper secondary schools. Skiers more often gave posi‐ tive answers to all questions on asthma and asthma‐associated symptoms. The cumulative prevalence of asthma was 15% in skiers and 6% in controls. We conclude that the common use of anti‐asthmatic drugs among cross‐country skiers reflects a high prevalence of self‐reported asthma and asthma‐associated symptoms. The causes of t

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00414.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The prevalence of asthma and exercise‐induced respiratory symptoms in 153 high‐level Norwegian cross‐country skiers and 306 control subjects were assessed in a postal survey. The response rates were 100% for the skiers and 79% for the controls. A present or past history of asthma was reported by 14% of the skiers and 5% of the controls. The prevalence of asthma increased signhcantly with increasing age among the skiers but not among the control subjects. The majority of the controls who reported asthma dated the onset of the disease to childhood, while the skiers dated the onset of asthma primarily to late adolescence or early adult life. The skiers used anti‐asthmatic medication significantly more often than did the controls. Exercise‐induced respiratory symptoms such as chest tightness, shortness of breath, cough, wheezing and sputum production were re‐ ported by 2–3 times as many skiers as controls. Exacerbation of respiratory symptoms was frequently associated with cold weather, humid weather or with recovering from an airway infection. The results of the present study indicate that cross‐country skiers may be at an increased risk for acquiring obstructive respir

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00415.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Longitudinal variations in bronchial responsiveness to methacholine was studied in 19 male crosscountry skiers 19–21 years old during the season of their sport and compared with the response in 22 age‐matched control subjects with minimal physical activity. The methacholine concentration required for a 10% fall in the forced expiratory volume in the first second (PC10) remained stable from August to November in the group of skiers, then decreased from November to February and finally increased from February to June. In the control group, PC10increased from August to November, increased further to February and finally decreased from February to June. Alternative methods for expressing bronchial responsiveness as the linear dosc‐response slope or the logarithmic dose‐response slope gave no more information than did PC10alone. High correlations were found between PC10and either of the dose‐response slopes. PC10and the dose response‐slopes were equally reproducible when measured on two successive days. In contrary to the control group, high‐performance cross‐ country skiers demonstrated increased bronchial responsiveness in the winter. The PC10was an advantageous method for studying longitudinal changes in bronchial responsiveness among h

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00416.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The contribution of muscle contraction to the structural capacity of the lower leg has been studied in skeletally immature and mature rats. The right lower legs of both young and adult rats were fractured in 3‐point ventral cantilever bending during electrically induced muscle contraction. The left tibiae were dissected free of all soft tissues and tested as controls. The ultimate bending moment increased 73% in young and 84% in adult rats, compared with the control tibiae. The ultimate energy absorption increased 149% and 302% in the young and adult rats, respectively. Ultimate deflection increased 70% and 140%, whereas bending stiffness decreased 18% and 24% in the young and adult rats, respectively. The results show that the fracture mechanicsin vivoare different in the immature and mature skeleton. This finding is discussed in relation to the differences in tibial fracture incidence in young and adult alpine skier

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00417.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

The vascular supply of the anterior and posterior cruciate ligaments was investigated in 21 adult dogs. The investigations were camed out under general anesthesia, and respirators were used. Measurements of the blood supply were performed by means of a microsphere technique. The ligaments were divided equally into a proximal part, a middle part and a distal part. Values recorded regarding the 3 parts of the anterior ligament were 3.0, 2.2 and 3.5 ml per 100 g of tissue per min respectively. As to the posterior ligament the respective values were 2.8, 2.8, and 3.2 ml per 100 g of tissue per min. No significant difference between the two ligaments or their various parts could be detected.

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00418.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

A prospective one‐year epidemiological study was carried out to determine the injury incidence and the injury mechanisms in different groups of gymnasts and to identify possible risk factors. A total of 115 gymnasts with a median age of 16 (8‐25) were followed through a whole season of median 48 weeks (ranges 40–51). The overall injury incidence was 85 per 100 gymnasts per season, ranging from 27 in subelite males to 157 in subelite females. This high incidence is partly explained by the use of a sensitive injury definition, the high exposure time, and the large proportion of highly competitive gymnasts in the population. Considering the exposure time, however, the incidence is lower than in most other sports, 1.6 per 1000 h of gymnastic activity. Subelite female gymnasts were more commonly injured than other artistic gymnasts, in particular in relation to balance beam exercises and inadequate spotting. Injuries were predominantly localized to the lower extremities (64%) for the whole population of gymnasts. A siwcantly large proportion of the male artistic gymnasts, nevertheless, sustained upper extremity injuries corresponding to their apparatus performance. Most injuries were of mild or moderate severity, the recovery time was, however, considerable (median 30 days, ranges 1–365), and the injuries sustained during competition had a median recovery period of 180 days (7‐270). Twenty‐two per cent of the injuries resulted in a recovery period of more than 6 months. Re‐evaluation of the criteria of the score system for dismount as well as an increased use of spotters during practice and high‐risk events are possible measures to prevent s

ISSN:0905-7188    

DOI:10.1111/j.1600-0838.1994.tb00419.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY