Gymnastik- och idrottshögskolan, GIH

Praktiskt taget alla vuxna svenskar anser att regelbunden motion är bra för hälsa och arbetsförmåga. Vi är också upplysta om hur våra matvanor, alkoholintag och rökning påverkar vår hälsa. Varför är det då en minoritet som har en livsstil som styrs av kunskap och förnuft? Finns svaret förankrat i vårt biologiska arv? Hur levde våra förfäder? Att sitta still i flera timmar utan att röra sig alls utgör en risk för utveckling av hjärt- och kärlsjukdom, cancer och annan ohälsa, trots att man kanske motionerar ett par gånger i veckan. Den fysiologiska förklaringen är den att om inte musklerna får arbeta regelbundet, om än mycket lite, så påverkas viktiga processer i musklerna, som sedan påverkar hela kroppen. Det räcker att regelbundet resa sig och gå en liten bit för att undvika de negativa effekterna av långvarigt sittande.I Född till rörelse kan du läsa om faktorer som har betydelse för vår kondition och hälsa. Varför är det så viktigt att vi rör på oss? Hur kan man motverka eller mildra effekten av vissa sjukdomar? Vad innebär det att vara fysiskt aktiv? Hur ska man träna och hur jobbigt bör det vara?

Olle Halldén var en svensk pionjär och centralgestalt inom pedagogik och humaniora inom kroppsövningsområdet i Sverige. Han var utbildad till gymnastikdirektör och under många år lärare vid Kungl. Gymnastiska Centralinsitutet/Gymnastik- och idrottshögskolan i Stockholm. 

In two articles Timothy Noakes proposes a new physiological model in which skeletal muscle recruitment is regulated by a central "govenor," specifically to prevent the development of a progressive myocardial ischemia that would precede the development of skeletal muscle anaerobiosis during maximal exercise. In this rebuttal to the Noakes' papers, we argue that Noakes has ignored data supporting the existing hypothesis that under normal conditions cardiac output is limiting maximal aerobic power during dynamic exercise engaging large muscle groups.

In 1949, 27 female and 26 male physical education students were studied at a mean age of 22 and 25 yr, respectively. They were restudied in 1970 and 1982. Measurements included oxygen uptake, heart rate, and pulmonary ventilation during submaximal and maximal exercise on a cycle ergometer and treadmill. After 21 yr, peak aerobic power was significantly reduced, from 2.90 to 2.18 l/min and from 4.09 to 3.28 l/min for women and men, respectively. After another 12 yr, the 1970 maxima were not reduced further. From 1949 to 1982 there was a decrease in peak heart rate from 196 to 177 beats/min in women and from 190 to 175 beats/min in men (P < 0.05). Highest pulmonary ventilation did not change significantly. At an oxygen uptake of 1.5 l/min, the heart rate was the same in 1949 as in 1982. In conclusion, the physical fitness level of the subjects was well above average for these ages. From 1970 to 1982 there was no decline in the average peak aerobic power, a finding possibly related to increased habitual physical activity.

Although the great explorers were well aware that eating fat was an efficient way to meet their large energy demand, it was not until some decades into this century that it could be demonstrated that lipids are metabolized directly by contracting skeletal muscles. The 1950s produced the first studies with [14C]-tagged fatty acids (FAs), proving that fat is transported into the cell as FAs. An FA-transporting protein that is present in the sarcolemma and in the cytoplasma has been identified. For FA transport into the mitochondria, carnitine and carnitine transferase are needed. It is still unclear how the use of lipids as an energy source for the muscle during exercise is limited. The supply of free fatty acids (FFAs) far exceeds what is taken up by the muscle. Seldom more than 2-4% of the amount of FFAs delivered to an exercising limb is taken up by the muscles and only part of it is oxidized. Physical training induces changes that enhance the uptake of FAs by the contracting muscles, and a larger fraction of this uptake is oxidized, but it is not yet clear which mechanism is behind this adaptation. What is known is that this uptake occurs despite no elevation in the amount of FA supplied to the limb.

There is a pronounced plasticity and adaptability in the structural and/or functional properties of cells, tissues, and organ systems in the human body when exposed to various stimuli. While there is unanimous agreement that regular exercise is essential for optimal function of the human body, it is evident that extrinsic factors, such as diet and exercise habits, are reflected in the morbidity and mortality statistics, especially in the aged. Aging is obligatorily associated with reduced maximal aerobic power and reduced muscle strength, i.e., with reduced physical fitness. As a consequence of diminished exercise tolerance, a large and increasing number of elderly persons will be living below, at, or just above "thresholds" of physical ability, needing only a minor intercurrent illness to render them completely dependent. Physical training can readily produce a profound improvement of functions essential for physical fitness in old age. Adaptability to regular physical activity serves to cause less disruption of the cell's "milieu interieur" and minimizes fatigue, thereby enhancing performance and the economy of energy output during exercise.

There is unanimous agreement that regular exercise is essential for optimal function of the human body. It is evident that extrinsic factors, such as diet and exercise habits, are reflected in the morbidity and mortality statistics, especially in aging. Aging is obligatorily associated with reduced maximal aerobic power and reduced muscle strength, ie, with reduced physical fitness. As a consequence of diminished exercise tolerance, a large and increasing number of elderly people will be living below, at, or just above "thresholds" of physical ability, needing only a minor intercurrent illness to render them completely dependent. Physical training can readily produce a profound improvement of functions also essential for physical fitness in old age. From a nutritional viewpoint one advantage of physical activity, and increased metabolic rate, is that a higher energy intake can better secure an adequate intake of essential nutrients.

The influence of catecholamines and branched-chain amino acids (BCAA) plus insulin on protein degradation and amino acid metabolism was investigated in isolated and electrically stimulated rat epitrochlearis muscles. 10(-7) M adrenaline significantly increased the total amount of muscle tyrosine during 40 min of stimulation with 50 Hz (I s min 1) pulse trains. On the other hand, BCAA + insulin at normal and five times normal plasma concentrations had no effect on muscle tyrosine. Muscle 3- methylhistidine was not influenced by any of the treatments. Muscle release and content of aspartate, alanine, glutamate and glutamine showed individual response characteristics to catecholamines and BCAA + insulin. The data indicate that adrenaline can induce an increased total protein degradation in rat fast muscle during acute contractions in vitro and, furthermore, that BCAA + insulin does not retard protein breakdown during acute muscle contraction.