The purpose of this Position Stand is to provide guidance to professionals who counsel and prescribe individualized exercise to apparently healthy adults of all ages. These recommendations also may apply to adults with certain chronic diseases or disabilities, when appropriately evaluated and advised by a health professional. This document supersedes the 1998 American College of Sports Medicine (ACSM) Position Stand, "The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults." The scientific evidence demonstrating the beneficial effects of exercise is indisputable, and the benefits of exercise far outweigh the risks in most adults. A program of regular exercise that includes cardiorespiratory, resistance, flexibility, and neuromotor exercise training beyond activities of daily living to improve and maintain physical fitness and health is essential for most adults. The ACSM recommends that most adults engage in moderate-intensity cardiorespiratory exercise training for ≥30 min·d on ≥5 d·wk for a total of ≥150 min·wk, vigorous-intensity cardiorespiratory exercise training for ≥20 min·d on ≥3 d·wk (≥75 min·wk), or a combination of moderate- and vigorous-intensity exercise to achieve a total energy expenditure of ≥500-1000 MET·min·wk. On 2-3 d·wk, adults should also perform resistance exercises for each of the major muscle groups, and neuromotor exercise involving balance, agility, and coordination. Crucial to maintaining joint range of movement, completing a series of flexibility exercises for each the major muscle-tendon groups (a total of 60 s per exercise) on ≥2 d·wk is recommended. The exercise program should be modified according to an individual's habitual physical activity, physical function, health status, exercise responses, and stated goals. Adults who are unable or unwilling to meet the exercise targets outlined here still can benefit from engaging in amounts of exercise less than recommended. In addition to exercising regularly, there are health benefits in concurrently reducing total time engaged in sedentary pursuits and also by interspersing frequent, short bouts of standing and physical activity between periods of sedentary activity, even in physically active adults. Behaviorally based exercise interventions, the use of behavior change strategies, supervision by an experienced fitness instructor, and exercise that is pleasant and enjoyable can improve adoption and adherence to prescribed exercise programs. Educating adults about and screening for signs and symptoms of CHD and gradual progression of exercise intensity and volume may reduce the risks of exercise. Consultations with a medical professional and diagnostic exercise testing for CHD are useful when clinically indicated but are not recommended for universal screening to enhance the safety of exercise.

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Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory, Musculoskeletal, and Neuromotor Fitness in Apparently Healthy Adults: Guidance for Prescribing Exercise

2 1 The innovative transport systems and the CityMobil project 10 1.1 The research questions 10 2 The state of art in the field of automatic transport systems 12 2.1 Case studies and demand studies for innovative transport systems 12 3 The design and implementation of surveys 14 3.1 Definition of experimental design 14 3.2 Questionnaire design and delivery 16 3.3 First analyses on the collected sample 18 4 Calibration of Logit Multionomial demand models 21 4.1 Methodology 21 4.2 Calibration of the “full” model. 22 4.3 Calibration of the “final” model 24 4.4 The demand analysis through the final Multinomial Logit model 25 5 The analysis of interaction between the demand and socioeconomic attributes 31 5.1 Methodology 31 5.2 Application of Mixed Logit models to the demand 31 5.3 Analysis of the interactions between demand and socioeconomic attributes through Mixed Logit models 32 5.4 Mixed Logit model and interaction between age and the demand for the CTS 38 5.5 Demand analysis with Mixed Logit model 39 6 Final analyses and conclusions 45 6.1 Comparison between the results of the analyses 45 6.2 Conclusions 48 6.3 Answers to the research questions and future developments 52

The European commission

Regular exercise offers protection against all-cause mortality, primarily by protection against cardiovascular disease and Type 2 diabetes mellitus. The latter disorders have been associated with chronic low-grade systemic inflammation reflected by a two- to threefold elevated level of several cytokines. Adipose tissue contributes to the production of TNF-alpha, which is reflected by elevated levels of soluble TNF-alpha receptors, IL-6, IL-1 receptor antagonist, and C-reactive protein. We suggest that TNF-alpha rather than IL-6 is the driver behind insulin resistance and dyslipidemia and that IL-6 is a marker of the metabolic syndrome, rather than a cause. During exercise, IL-6 is produced by muscle fibers via a TNF-independent pathway. IL-6 stimulates the appearance in the circulation of other anti-inflammatory cytokines such as IL-1ra and IL-10 and inhibits the production of the proinflammatory cytokine TNF-alpha. In addition, IL-6 enhances lipid turnover, stimulating lipolysis as well as fat oxidation. We suggest that regular exercise induces suppression of TNF-alpha and thereby offers protection against TNF-alpha-induced insulin resistance. Recently, IL-6 was introduced as the first myokine, defined as a cytokine that is produced and released by contracting skeletal muscle fibers, exerting its effects in other organs of the body. Here we suggest that myokines may be involved in mediating the health-beneficial effects of exercise and that these in particular are involved in the protection against chronic diseases associated with low-grade inflammation such as diabetes and cardiovascular diseases.

The anti-inflammatory effect of exercise

Repeated, intense use of muscles leads to a decline in performance known as muscle fatigue. Many muscle properties change during fatigue including the action potential, extracellular and intracellular ions, and many intracellular metabolites. A range of mechanisms have been identified that contribute to the decline of performance. The traditional explanation, accumulation of intracellular lactate and hydrogen ions causing impaired function of the contractile proteins, is probably of limited importance in mammals. Alternative explanations that will be considered are the effects of ionic changes on the action potential, failure of SR Ca2+ release by various mechanisms, and the effects of reactive oxygen species. Many different activities lead to fatigue, and an important challenge is to identify the various mechanisms that contribute under different circumstances. Most of the mechanistic studies of fatigue are on isolated animal tissues, and another major challenge is to use the knowledge generated in these studies to identify the mechanisms of fatigue in intact animals and particularly in human diseases.

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Skeletal Muscle Fatigue: Cellular Mechanisms

Statistical Methods for Health Care Research

The present study investigated the effects of hyperthermia on the contributions of central and peripheral factors to the development of neuromuscular fatigue. Fourteen men exercised at 60% maximal ...

https://www.physiology.org/doi/pdf/10.1152/jappl.2001.91.3.1055

Hyperthermia and central fatigue during prolonged exercise in humans

Cerebral perturbations provoked by prolonged exercise.

NYBO, L., E. SUNDSTRUP, M. D. JAKOBSEN, M. MOHR, T. HORNSTRUP, L. SIMONSEN, J. BULOW, M. B. RANDERS, J. J. NIELSEN, P. AAGAARD, and P. KRUSTRUP. High-Intensity Training versus Traditional Exercise Interventions for Pro- moting Health. Med. Sci. Sports Exerc., Vol. 42, No. 10, pp. 1951-1958, 2010. Purpose: The purpose of this study was to deter- mine the effectiveness of brief intense interval training as exercise intervention for promoting health and to evaluate potential benefits about common interventions, that is, prolonged exercise and strength training. Methods: Thirty-six untrained men were divided into groups that completed 12 wk of intense interval running (INT; total training time 40 minIwk j1 ), prolonged running (E150 minIwk j1 ), and strength training (E150 minIwk j1 ) or continued their habitual lifestyle without participation in physical training. Results: The improvement in cardiorespiratory fitness was superior in the INT (14% T 2% increase in VO2max) compared with the other two exercise interventions (7% T 2% and 3% T 2% increases). The blood glucose concentration 2 h after oral ingestion of 75 g of glucose was lowered to a similar extent after training in the INT (from 6.1 T 0.6 to 5.1 T 0.4 mM, P G 0.05) and the prolonged running group (from 5.6 T 1.5 to 4.9 T 1.1 mM, P G 0.05). In contrast, INT was less efficient than prolonged running for lowering the subjects' resting HR, fat percentage, and reducing the ratio between total and HDL plasma cholesterol. Furthermore, total bone mass and lean body mass remained unchanged in the INT group, whereas both these parameters were increased by the strength-training intervention. Conclusions: INT for 12 wk is an effective training stimulus for improvement of cardiorespiratory fitness and glucose tolerance, but in relation to the treatment of hyperlipidemia and obesity, it is less effective than prolonged training. Furthermore and in contrast

High-intensity training versus traditional exercise interventions for promoting health.

The relationship between quadriceps muscle temperature (T(m)) and sprint performance was evaluated during soccer matches in 25 competitive players. In one game, T(m) was determined frequently (n=9). In another game, eight players performed low-intensity activities at half-time (re-warm-up, (RW), whereas another eight players recovered passively (CON). T(m) was 36.0+/-0.2 degrees C at rest and increased (P<0.05) to 39.4+/-0.2 degrees C before the game and remained unaltered during the first half. At half-time, T(m) decreased (P<0.05) to 37.4+/-0.2 degrees C, but increased (P<0.05) to 39.2+/- degrees C during the second half. In CON and RW, T(m) and core temperature (T(c)) were similar before and after the first half, but 2.1+/-0.1 and 0.9+/-0.1 degrees C higher (P<0.05), respectively, in RW prior to the second half. At the onset of the second half, the sprint performance was reduced (P<0.05) by 2.4% in CON, but unchanged in RW. The decrease in T(m) was correlated to the decrease in performance (r=0.60, P<0.05, n=16). This study demonstrates that in soccer, the decline in T(m) and T(c) during half-time is associated with a lowered sprint capacity at the onset of the second half, whereas sprint performance is maintained when low-intensity activities preserve muscle temperature.

Muscle temperature and sprint performance during soccer matches--beneficial effect of re-warm-up at half-time.

KRUSTRUP, P., M. MOHR, L. NYBO, J. MAJGAARD JENSEN, J. JUNG NIELSEN, and J. BANGSBO. The Yo-Yo IR2 Test: Physiological Response, Reliability, and Application to Elite Soccer. Med. Sci. Sports Exerc., Vol. 38, No. 9, pp. 1666–1673, 2006. Purpose: To examine the physiological response, reliability, and validity of the Yo-Yo intermittent recovery level 2 test (Yo-Yo IR2). Methods: Thirteen normally trained male subjects carried out four Yo-Yo IR2 tests, an incremental treadmill test (ITT), and various sprint tests. Muscle biopsies and blood samples were obtained, and heart rate was measured before, during, and after the Yo-Yo IR2 test. Additionally, 119 Scandinavian elite soccer players carried out the Yo-Yo IR2 test on two to four occasions. Results: Yo-Yo IR2 performance was 591 T 43 (320–920) m or 4.3 (2.6–7.9) min. Test–retest coefficient of variation in distance covered was 9.6% (N = 29). Heart rate (HR) at exhaustion was 191 T 3 bpm, or 98 T 1% HRmax. Muscle lactate was 41.7 T 5.4 and 68.5 T 7.6 mmolIkg j1 d.w. at 85 and 100% of exhaustion time, respectively, with corresponding muscle CP values of 40.4 T 5.2 and 29.4 T 4.7 mmolIkg j1 d.w. Peak blood lactate was 13.6 T 0.5 mM. Yo-Yo IR2 performance was correlated to ITT performance (r = 0.74, P G 0.05) and V u O2max (r = 0.56, P G 0.05) but not to 30- and 50-m sprint performance. Yo-Yo IR2 performance was better (P G 0.05) for international elite soccer players than for moderate elite players (1059 T 35 vs 771 T 26 m) and better (P G 0.05) for central defenders (N = 21), fullbacks (N =2 0), and midfielders (N = 48) than for goalkeepers (N = 6) and attackers (N = 24). Fifteen elite soccer players improved (P G 0.05) Yo-Yo IR2 performance by 42 T 8% during 8 wk of preseasonal training. Conclusion: This study demonstrates that the Yo-Yo IR2 test is reproducible and can be used to evaluate an athlete_s ability to perform intense intermittent exercise with a high rate of aerobic and anaerobic energy turnover. Specifically, the Yo-Yo IR2 test was shown to be a sensitive tool to differentiate between intermittent exercise

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Lars Nybo

Papers

Hyperthermia and central fatigue during prolonged exercise in humans

Cerebral perturbations provoked by prolonged exercise.

High-intensity training versus traditional exercise interventions for promoting health.

Muscle temperature and sprint performance during soccer matches--beneficial effect of re-warm-up at half-time.

The Yo-Yo IR2 test: physiological response, reliability, and application to elite soccer.