Made available in DSpace on 2014-08-20T13:49:10Z (GMT). No. of bitstreams: 1 Carlos Marcelo Cuello Moreno.pdf: 1387202 bytes, checksum: b79b74e0ffec1416ed9d352034574c31 (MD5) Previous issue date: 2013-02-27 / Low-intensity chronic systemic inflammation is related to an increased risk of cardiovascular disease. Studies suggest that C-reactive protein, one of the main inflammatory biomarkers, may be inversely related to physical activity levels and physical fitness. The aim of this cross-sectional study was to evaluate the associations between physical activity, fitness and inflammatory biomarkers in apparently healthy men (N=85) aged 18 to 30 years. C-reactive protein was measured using the ELISA method. Physical activity practice was assessed by questionnaire and accelerometry. Maximum oxygen uptake (VO2max) was estimated based on a cycle ergometer incremental test. In the unadjusted analysis, the mean concentrations of C-reactive protein in the sample was 1.59±1.16 mg/L, and was inversely correlated with VO2max (r=-0.32, p=0.03). The body mass index (BMI) and waist circumference also significantly correlated with C-reactive protein (r=0.37, p<0.001 and r=0.41, p<0.001, respectively). After adjustment for anthropometric characteristics (BMI and waist circumference), the association with fitness was no longer significant. No association was observed between physical activity levels (questionnaire and accelerometry) and C-reactive protein. We conclude the in this group of young adults there was an inverse association between fitness and C-reactive protein, and this association is explained by the influence of fitness on anthropometry. / A inflamação sistêmica crônica de baixa intensidade está relacionada com maior risco de doenças cardiovasculares. Estudos sugerem que a proteína C-reativa, um dos principais biomarcadores inflamatórios, pode estar inversamente relacionada com a prática de atividade física e com a aptidão física. O objetivo deste estudo transversal foi determinar as associações entre os níveis de atividade física e a aptidão cardiorrespiratória, com biomarcadores inflamatórios em homens adultos jovens (18-30 anos) aparentemente saudáveis (N=85). A concentração sérica da proteína C-reativa foi avaliada pelo método ELISA. A prática de atividade física foi mensurada por questionário e acelerometria. O consumo máximo de oxigênio (VO2max) foi estimado por teste incremental em cicloergômetro. Na análise bruta, a média das concentrações de proteína C-reativa da amostra foi de 1,59±1,16 mg/L, e esteve significativamente correlacionada com o VO2max (r=-0,32; p=0,03). O índice de massa corporal (IMC) e a circunferência abdominal também apresentaram correlação significativa com a proteína C-reativa (r=0,37; p<0,001 e r=0,41; p<0,001, respectivamente). Quando realizamos ajuste para as variáveis antropométricas (IMC e circunferência da cintura), a associação deixou de ser significativa. Diferentemente do IMC e circunferência abdominal, que continuaram tendo associação estatisticamente significativa com a proteína C-reativa mesmo ajustando para o VO2max. Não houve relação entre proteína C-reativa e níveis de atividade física, medidos por questionário ou acelerômetro. Conclui-se que nesse grupo de adultos jovens houve relação entre a proteína C-reativa e o VO2max, e que esta associação é explicada pelas modificações no perfil antropométrico decorrentes de altos níveis de aptidão cardiorrespiratória.

The objective of this thesis is to evaluate the cardiorespiratory fitness of sportsmen and obese patients through the medium of spiroergometry on cycloergometer by virtue of the analyzer of exhaled gas (Oxycon). Its advantage is that the measurement takes place "on- line", therefore it allows prompt monitoring of measured spiroergometric parameters directly on screen of computer that forms part of the analyzer. The spiroergometry is a method of determining the cardiorespiratory fitness through the medium of analyzer of exhaled gas in order to state the physical fitness. For statistical evaluation of differences in values of spiroergometric indicators between these two observed groups of patients I used the Student's unpaired T-test. The theoretical part contains an introduction into the issue of obesity, obesity epidemiology, history, aetiology and health risks of this disease, classification, diagnostics, treatment, and recommendations and advices for patients. Furthermore it contains terms as sports medicine, influence of motional activity on human organism, cardiorespiratory fitness, spiroergometry methodology, and spiroergometric parameters. The practical part contains a description of spiroergometric measuring process at the Institute of Sports Medicine at the 1st Faculty of Medicine of the...

Rates of obesity (OB) are escalating among Canadian children and youth and the obesogenic environment is likely to cause further increases. An important aspect in providing clinical care to OB children is to have accurate assessment measures, particularly of their body composition and cardiorespiratory fitness. This project entails three interrelated projects aiming to develop novel cardiorespiratory fitness and body composition measurement techniques for an OB pediatric population. The purpose of the first project was to validate a new submaximal fitness protocol specifically geared towards OB children and youth. The second objective of this thesis involved assessing cardiorespiratory efficiency utilizing the Oxygen Uptake efficiency slope. The purpose of the third project was to determine the validity of a half-body scan methodology for measuring body composition in obese children and youth. The goal of developing these novel measurement techniques is improved design and evaluation of interventions aimed at managing pediatric obesity.

Prevalence of physical inactivity in children and adolescents and the associated epidemic of obesity are increasing concerns. U.S. national health statistics indicate early adolescence (i.e., 10-14 years) appears to be a period of importance regarding physical activity, sedentary behavior, health-related physical fitness, and obesity trends. Considering a significant portion of their waking hours are spent in school, it is widely held that schools' should play a significant role in increasing students' physical activity and health-related physical fitness. To do this, physical education in schools focus on providing quality physical education programs that produce physically literate individuals who have the knowledge, skills, and confidence to enjoy a lifetime of health-producing physical activity. In effect, a call for developing a comprehensive and valid measure of physical literacy has been aptly expressed. Thus, the purpose of this dissertation was to test the psychometric properties of proposed models of physical literacy, examine correlates of the physical literacy factor, and investigate the significance of the relationship between physical literacy and interscholastic sport intention via structural equation modeling. Participants were 400 (231 female, 169 male) sixth-grade physical education students who completed three brief surveys assessing maturation, self-efficacy, self-esteem, knowledge and understanding, motivation, physical activity and sport participation, and interscholastic sport intention. In addition, students completed a sedentary behavior log, a health-related physical fitness assessment, and an overhand throwing skill assessment. Analyses offered overall support for the proposed physical literacy measurement models. Results also supported positive relationship Physical literacy was statistically significantly positively related physical activity and sport team participation, and significantly negatively related and screen-time sedentary behavior. Results also supported a positive path between physical literacy and interscholastic sport intention. The implications of promoting physical literacy within physical education are discussed in light of the three higher-order underlying factors of physical literacy.

Cardiovascular disease is the main cause of death in the United States. Although it is recognized that moderate intensity long-term exercise can decrease the chances of dying from cardiovascular disease by favorably modifying risk factors such as hypertension, obesity, hyperlipidemia, and insulin resistance, physical activity also enhances longevity by mechanisms independent of these risk factors. This review briefly summarizes what is known about the inflammatory nature of atherosclerosis and how long-term aerobic exercise can reduce the atherogenic activity of endothelial cells, blood mononuclear cells, and adipose tissue.

No description available.

Il est reconnu que les survivants d’accident vasculaire cérébral (AVC) présentent un important déconditionnement physique ainsi qu’une grande prévalence de comorbidités cardiovasculaires qui augmente considérablement le risque de subir un autre événement cardiovasculaire. En prévention secondaire, mis à part le traitement pharmacologique, il existe actuellement très peu de prise en charge de ces facteurs de risque lors de la phase de retour en communauté des patients. Pourtant, les lignes directrices recommandent l’activité physique de type aérobie comme moyen efficace de prévention cardiovasculaire. Par ailleurs, il existe de plus en plus de données probantes suggérant que l’entraînement par intervalles à haute intensité (HIIT) représenterait une forme d’exercice efficace pour améliorer la capacité cardiorespiratoire et le profil de santé chez différentes populations symptomatiques. La littérature demeure, toutefois, limitée quant à l’utilisation de cette méthode post-AVC. L’objectif général de cette thèse était de développer et d’évaluer un programme d’exercice incluant le HIIT en combinaison avec l’entraînement continu à intensité moyenne (MICT) pour les personnes ayant vécu un AVC ischémique ou une ischémie cérébrale transitoire (ICT) en prévention secondaire dans la phase chronique de la maladie. Les différentes étapes de cette recherche ont permis la rédaction de quatre articles scientifiques. Premièrement, la faisabilité et l’acceptabilité du protocole d’exercice élaboré incluant le HIIT ont été évaluées de façon favorable à la suite d’une intervention de trois mois. Cette première étude aura permis d’optimiser notre protocole pour développer les étapes subséquentes. En second lieu, l’efficacité du protocole lors d’une intervention de six mois a été évaluée dans une étude contrôlée randomisée en démontrant notamment une amélioration de la capacité cardiorespiratoire ainsi que des marqueurs d’anxiété et de dépression qui persistaient six mois après l’arrêt du programme supervisé comparativement à un groupe contrôle. Cette deuxième étude a également permis de comparer notre programme combiné contenant du HIIT à un programme d’activité physique standard comprenant seulement du MICT, sans toutefois démontrer aucune supériorité du protocole expérimental sur les variables cliniques mesurées. En troisième lieu, les réponses aiguës de la mesure ambulatoire de la pression artérielle à la suite d’un entraînement HIIT et à un iv entraînement MICT ont démontré un effet hypotenseur perdurant jusqu’à huit heures post-exercice, lequel était comparable pour les deux types d’entraînement. Finalement, une quatrième étude qualitative a permis de mettre en lumière une acceptabilité favorable des participants au programme comprenant du HIIT en plus de permettre de comprendre leur expérience afin de bonifier et d’optimiser des recherches futures. Cette thèse a contribué à l’avancement des connaissances en lien avec l’utilisation de la méthode HIIT chez les victimes d’AVC ischémique ou d’ICT dans la phase de réintégration et de maintien en communauté du continuum de soins post-AVC. Cette recherche a démontré un effet favorable sur des variables cliniques en plus d’avoir mis de l’avant l’acceptabilité positive du projet par les participants. Toutefois, les résultats ne supportent pas de supériorité d’inclure la méthode HIIT par rapport à l’utilisation du MICT seulement. Cette thèse soutient donc que l’ajout du HIIT pourrait être une alternative efficace dans un objectif de prévention secondaire en phase chronique de l’AVC ischémique et de l’ICT. Ce qui importe réellement est de rendre l’activité physique aérobie accessible, faisable et acceptable pour améliorer la santé et la qualité de vie des survivants d’AVC. / Stroke survivors have significant physical deconditioning and a high prevalence of cardiovascular comorbidities that significantly increase the risk of another cardiovascular event. In secondary prevention, apart from pharmacological treatment, there is currently little management of these risk factors during the phase of community reintegration. However, guidelines recommend aerobic exercise as an effective method of cardiovascular protection. In addition, there is growing evidence to suggest that high-intensity interval training (HIIT) is an effective form of exercise for improving cardiorespiratory fitness and health profile in different symptomatic populations. However, the literature remains limited on the use of this method post-stroke. The overall objective of this thesis was to develop et evaluate a realistic physical activity program including a combination of HIIT and moderate intensity continuous training (MICT) for people with ischemic stroke or transient ischemic attack (TIA) for secondary prevention in the chronic phase of the disease, thus addressing a clinical need. The different steps of this research led to the writing of four scientific articles. First, the feasibility and acceptability of the protocol developed were favorably evaluated following a three-month intervention. This first study allowed us to optimize our protocol to develop the subsequent steps. Secondly, the effectiveness of our protocol during a sixmonth intervention was evaluated in a randomized controlled study by demonstrating an improvement in cardiorespiratory capacity as well as markers of anxiety and depression that persisted six months after the program supervision was stopped compared to a control group. This second study also compared our program containing HIIT to a standard physical activity program with MICT without, however, showing any superiority of our combinated protocol on our variables. Third, the acute responses of ambulatory blood pressure measurement following HIIT training and MICT training demonstrated a hypotensive effect lasting up to eight hours post-exercise that was comparable for both types of intervention. Finally, a fourth qualitative study revealed a favorable acceptability of the participants to the combined program including HIIT and allowed us to understand their experience in order to improve and optimize future research. This thesis has contributed to the advancement of knowledge related to the use of HIIT post-stroke or TIA. Our research has demonstrated a positive effect on clinical variables and has highlighted the positive acceptability of the project by the participants. However, our results do not support a superiority of including the HIIT method over the use of MICT alone. This thesis therefore argues that the addition of HIIT could be an effective alternative in a secondary prevention goal in the chronic phase of ischemic stroke and TIA, but what really matters is making aerobic physical activity accessible to improve the health and quality of life of stroke survivors.

Syfte och frågeställningar. Syftet med studien är att, hos äldre personer, över 65 år, samt hos yngre vuxna, mellan 20-30 år, jämföra syreupptagningsförmågan med två olika metoder, fem-minuterspyramidtest (5MPT) samt VO2max-test på löpband. Vid båda mätmetoderna används direkt syrgasmätning. Metod. Totalt deltog 36 personer i studien, varav 17 äldre personer 65 till 85 år (9 kvinnor och 8 män) samt 19 yngre med en ålder mellan 20 till 35 år (10 kvinnor och 9 män). Deltagarnas syreupptagningsförmåga mättes under 5MPT vid två tillfällen som sedan jämfördes med VO2max mätt via ett maximalt test på löpband vid ett tillfälle. Således utfördes sammanlagt tre mätningar med direkt syrgasmätning, via andningsmask, under ett maximalt löpbandstest samt under två separata tester av 5MPT med minst 48 timmar mellan varje testtillfälle. Utandningsluften analyserades sedan, vid 5MPT för alla, via det trådlösa portabla systemet Jaeger Oxycon Mobile och vid test på löpband för testgruppen med yngre deltagare. För den testgrupp med äldre deltagare användes, vid testet på löpband, den fasta on-line-utrustningen Jaeger Oxycon Pro som är en liknande mätmetod för syreupptag. 5MPT är ett fem minuter långt test där individen från golvnivå, med högsta möjliga tempo, förflyttar sig fram och tillbaka på en 5,50 meter lång sträcka med en centralt placerad trappramp som är pyramidformad och med en högsta central höjd på 0,62 meter. Resultat. Det primära fyndet i studien var att en stark signifikant korrelation (r = 0,99) visade sig mellan direkt uppmätt VO2max under maximalt test på löpband gentemot syreupptagningsförmågan vid 5MPT då båda åldersgrupperna var sammanslagna, uppmätt i l·min–1. Slutsats. Då det i undersökningen visades en stark signifikant korrelation mellan direkt uppmätt VO2max vid 5MPT och ett maximalt test på löpband i l·min–1 för äldre och yngre vuxna ger det indikationer på att 5MPT kan används som en tillförlitlig metod vid undersökning och uppföljning av en persons aeroba förmåga. Fyndet kan vara av värde då det genom mindre kostsamma och enklare metoder går att få ett mått på en persons hälsa i form av aerob kapacitet, vilket är betydelsefullt ur flera hälsoaspekter på individ- och samhällsnivå. / Aim. The purpose of the study was to investigate the results and correlation between oxygen uptake levels (VO2max) at five-minute pyramid test (5MPT) against maximal oxygen uptake test (VO2max) on a treadmill test, both measured by direct oxygen measurement, in elderly people over 65 years and younger adults aged 20-30 years. Method. A total of 36 people participated in the study, 17 elderly people aged between 65 to 85 years (9 women and 8 men) and 19 younger adults aged between 20 to 35 years (10 women and 9 men). The participants' oxygen uptake was measured twice during 5MPT and then compared with VO2max measured by a maximal treadmill test at one occasion. Thus a total of three measurements with direct oxygen measurement, via the breathing mask, during a maximum treadmill test and two separate tests of 5MPT with at least 48 hours between each test. The exhaled air was analyzed at 5MPT for all, through the wireless portable system Jaeger Oxycon Mobile and also during the test on treadmill for the test group with younger participants. The test group of older participants, got their exhaled air analyzed through a stationary on-line equipment Jaeger Oxycon Pro instead of the portable system which is a similar reliable method to measure VO2max. 5MPT is a five minute test where the subjects from floor level, with the highest possible speed, moves back and forth at a measured distance of 5.50 meter with a central staircase ramp, which is pyramid-shaped, with a maximum center height of 0.62 meters. Results. The main finding of the study was that there was a strong significant correlation (r = 0.99) between directly measured VO2max during a maximum treadmill test compared to oxygen uptake at 5MPT when both the elderly people and the younger adults were combined, measured in l·min–1. Conclusion. The study showed a strong significant correlation between directly measured VO2max at 5MPT and a maximal treadmill testing l·min–1 for older and younger adults. This indicates that 5MPT can be used as a reliable method for investigation and monitoring a person’s aerobic capacity. This finding may be of value because it shows that less expensive and easier methods can be used to measure a person's health in terms of aerobic capacity, which is important from several aspects of health at both the individual and society level.

Le sommeil, de par ses fonctions récupératrices, est essentiel à la vie. Pour autant, la modification du mode de vie et des comportements, tant sédentaires que nutritionnels, sont à l’origine d’une altération du sommeil, conduisant ensemble à des situations d’obésité. Cet excès pondéral s’accompagne fréquemment d’un syndrome d’apnées obstructives du sommeil (SAOS). Lorsque ces deux pathologies sont présentes, les troubles métaboliques s’aggravent et sont à l’origine d’une inflammation de bas grade. A notre connaissance, aucune étude ne s’est intéressée aux bénéfices d’un reconditionnement à l’exercice physique combiné à une modification des habitudes alimentaires, en dehors de ceux induits par la perte de poids, sur ces différents paramètres. L’objectif de ce travail de thèse a donc été, à partir d’une étude ancillaire, d’évaluer le sommeil d’adolescents obèses par polysomnographie (PSG) par comparaison à celui de sujets normo-pondérés. Dans l’étude principale, les effets d’un programme de 9 mois (reconditionnement à l’exercice, activités physiques adaptées, rééquilibre alimentaire) ont été évalués sur l’architecture et la durée du sommeil, le SAOS, les différents facteurs biologiques (inflammatoires, hormonaux, profils glucidique et lipidique) et sur les adaptations physiologiques à l’exercice musculaire, afin de mieux comprendre l’implication de l’endurance aérobie et des troubles du sommeil sur la santé cardio-métabolique. Trente-deux adolescents obèses (âge : 14,6 ans, z-score d’IMC= 4 ,7) ont été recrutés. Toutes les variables ont été analysées en pré et post-intervention. Les résultats montrent une durée de sommeil réduite chez les jeunes obèses avec un SAOS, diagnostiqué chez 58% d’entre eux, malgré une architecture du sommeil satisfaisante. En post-intervention, une perte de poids de 11 kg et une amélioration des paramètres d’adaptation à l’exercice maximal (PMA, VE, VO2pic…) ont été rapportées chez tous les sujets, que le SAOS soit encore, ou non, présent. En effet, ce syndrome s’est normalisé chez 46% d’entre eux. Par ailleurs, grâce à l’intervention, le sommeil s’est amélioré (qualité et quantité). Enfin, la protéine C-réactive basale du groupe SAOS, dont les valeurs atteignaient 11mg/l à l’admission, a considérablement diminué, accompagnée d’une baisse de la leptinémie et d’une hausse de l’adiponectinémie, pouvant expliquer le moindre risque cardio-métabolique. Nos résultats démontrent qu’à l’admission, l’inflammation est liée à l’obésité, alors qu’en post-intervention, sa baisse s’explique par l’augmentation de l’endurance aérobie, et ceci indépendamment du sexe, du poids, de la durée de sommeil et du SAOS. Bien que ce dernier n’ait pas été normalisé chez tous les sujets, sa prévention par l’exercice physique ainsi que celle des troubles métaboliques observés dans ces deux pathologies devrait faire partie intégrante de la prise en charge des jeunes obèses en vue d’atténuer le risque de morbi-mortalité cardiovasculaire à l’âge adulte / Sleep, through its restorative functions, is essential for life. However, lifestyle modifications, sedentary and unhealthy feeding behaviors trigger sleep curtailment and sleep disruption, leading together to weight gain. Obesity is usually associated with obstructive sleep apnea (OSA), and these two diseases both induce metabolic dysfunctions and low-grade systemic inflammation. To the best of our knowledge, no study has assessed the effects of exercise reconditioning and modified food habits on these parameters. The purpose of this work was to assess and compare, from an ancillary study, polysomnographic variables between obese adolescents and normal-weight (NW) controls. In the main study, the effects of a 9-month program (exercise reconditioning, adapted physical activities and modified food habits) on sleep architecture, sleep duration, OSA, biological factors (inflammatory, hormonal, carbohydrates and lipid profiles) and physiological adaptations at exercise were assessed, in order to a better understanding of the roles of cardiorespiratory fitness and sleep disorders on cardio-metabolic health. Thirty-two obese adolescents (age: 14.6 years, BMI z-score: 4.7) were recruited. Every parameters were assessed at admission and post-intervention. Short sleep duration and a high prevalence of OSA (58%) were observed at admission in obese adolescents despite a satisfying sleep architecture, compared with NW controls. Post-intervention, weight loss (11kg) and improved parameters of physiological adaptations at exercise (MAP, VE, VO2peak) were found in every subject and OSA was normalized in 46% of them. Sleep quantity and sleep quality were improved. Decreased C-reactive protein (6.78 vs 10.98 mg/l) and leptin concentrations, and increased adiponectin levels were found, and cardio-metabolic risk (CMR) was decreased. At admission, obesity explains by itself the systemic inflammation whereas the decrease in inflammation, post-intervention, is explained by enhanced cardiorespiratory fitness related to fat-free mass, after controlling for sex, weight loss, change in sleep duration and OSA. Prevention of OSA and metabolic dysfunctions by chronic exercise should be an integral part of the obesity management in youths in order to decrease the risk of cardiovascular morbi-mortality in adulthood

The 20 Metre Multistage Shuttle Run Test (20 MST) was modified for application to ice-sports, more specifically for ice-hockey and figure-skating. Seventy two participants in ice-sports served as the total subject group. Subjects included in the study were National and Provincial standard male ice-hockey subjects (n=67) and female figure skaters (n=5) participating in the Gauteng area of South Africa (altitude of 1497 metres above sea level and barometric pressure of 655 mmHg). The mean age for the total group was 17.44±1.33 years. The research methodology entailed a repeated measures design to determine: a) velocity of motion on-ice vs. over-ground; b) energy expenditure on-ice vs. over-ground; and c) mechanical efficiency on-ice vs. over-ground. The mean velocity of motion measured over three distances (0 to 20, 0 to 30 and 0 to 40 m) indicated a significantly (p≤0.05) faster velocity on-ice (5.99±0.72 m/s) versus over-ground (5.75±0.63 m/s). The corresponding mean time-lapsed on-ice/over-ground ratio was 0.97±0.11. Differences in mean energy expenditure whilst performing the original 20 MST over-ground as opposed to on-ice were measured at low (at 4 minutes of exercise and 10 km/h), intermediate (after 8 minutes of exercise and 12 km/h), and high intensity (after 12 min of exercise and 14 km/h). The mean of the three indicated a significantly (p≤0.05) higher energy expenditure over-ground (14.04±4.86 kcal/min) as apposed to on-ice (10.51±2.95 kcal/min). The mean energy expenditure ratio for the three different intensities on-ice vs. over-ground was 0.74±0.21. Similarly, the mechanical efficiency index over-ground (4.92±0.59) was found to be significantly (p≤0.001) poorer than on-ice (6.83±1.49). The mean mechanical efficiency ratio over-ground/over-ice was 0.74±0.13. Subsequently, based on the above results, the 20 MST was modified by: a) adapting (increasing) the velocity of motion required for each level of the test (distance of 20 m per shuttle); and b) establishing the reliability and validity of the modified 20 MST for use on-ice. The adapted 20 Metre Multistage Shuttle Skating Test (the modified (skating) 20 MST) started at a velocity of 2.8 m/s (10.1 km/h) and permitted 7.1 seconds to complete each shuttle for the first level of the test, which then decreased progressively at each level. This was based on an over-all variable-derived on-ice to over ground ratio of 0.84. Test-retest, on-ice reliability measures (n=15) for predicted VO2max (49.5±8.37 vs. 49.29±7.95 ml/kg/min) showed a highly significant (p£0.001) consistency (r=0.87). Similarly test-retest concurrent validity measures (n=10) for predicted VO2max over-ground with the original 20 MST (48.09±6.25 ml/kg/min) as designed by Léger and Lambert (1982) versus on-ice values with the adapted on-ice 20 MST (49.98±7.23 ml/kg/min), showed a very significant (p£0.01) correlation of 0.73 between the two tests. In conclusion the original 20 MST, as designed by Léger and Lambert (1982) for over-ground, proved inappropriate for use on-ice. Modification of the starting velocity as well as a progressive increase in velocity for all subsequent stages renders the modified 20 MST for ice-sports a reliable and valid test for cardiorespiratory fitness (VO2max), with surface-specific utility. The 20 Metre Multistage Shuttle Run Test (20 MST) was modified for application to ice-sports, more specifically for ice-hockey and figure-skating. Seventy two participants in ice-sports served as the total subject group. Subjects included in the study were National and Provincial standard male ice-hockey subjects (n=67) and female figure skaters (n=5) participating in the Gauteng area of South Africa (altitude of 1497 metres above sea level and barometric pressure of 655 mmHg). The mean age for the total group was 17.44±1.33 years. The research methodology entailed a repeated measures design to determine: a) velocity of motion on-ice vs. over-ground; b) energy expenditure on-ice vs. over-ground; and c) mechanical efficiency on-ice vs. over-ground. The mean velocity of motion measured over three distances (0 to 20, 0 to 30 and 0 to 40 m) indicated a significantly (p≤0.05) faster velocity on-ice (5.99±0.72 m/s) versus over-ground (5.75±0.63 m/s). The corresponding mean time-lapsed on-ice/over-ground ratio was 0.97±0.11. Differences in mean energy expenditure whilst performing the original 20 MST over-ground as opposed to on-ice were measured at low (at 4 minutes of exercise and 10 km/h), intermediate (after 8 minutes of exercise and 12 km/h), and high intensity (after 12 min of exercise and 14 km/h). The mean of the three indicated a significantly (p≤0.05) higher energy expenditure over-ground (14.04±4.86 kcal/min) as apposed to on-ice (10.51±2.95 kcal/min). The mean energy expenditure ratio for the three different intensities on-ice vs. over-ground was 0.74±0.21. Similarly, the mechanical efficiency index over-ground (4.92±0.59) was found to be significantly (p≤0.001) poorer than on-ice (6.83±1.49). The mean mechanical efficiency ratio over-ground/over-ice was 0.74±0.13. Subsequently, based on the above results, the 20 MST was modified by: a) adapting (increasing) the velocity of motion required for each level of the test (distance of 20 m per shuttle); and b) establishing the reliability and validity of the modified 20 MST for use on-ice. The adapted 20 Metre Multistage Shuttle Skating Test (the modified (skating) 20 MST) started at a velocity of 2.8 m/s (10.1 km/h) and permitted 7.1 seconds to complete each shuttle for the first level of the test, which then decreased progressively at each level. This was based on an over-all variable-derived on-ice to over ground ratio of 0.84. Test-retest, on-ice reliability measures (n=15) for predicted VO2max (49.5±8.37 vs. 49.29±7.95 ml/kg/min) showed a highly significant (p£0.001) consistency (r=0.87). Similarly test-retest concurrent validity measures (n=10) for predicted VO2max over-ground with the original 20 MST (48.09±6.25 ml/kg/min) as designed by Léger and Lambert (1982) versus on-ice values with the adapted on-ice 20 MST (49.98±7.23 ml/kg/min), showed a very significant (p£0.01) correlation of 0.73 between the two tests. In conclusion the original 20 MST, as designed by Léger and Lambert (1982) for over-ground, proved inappropriate for use on-ice. Modification of the starting velocity as well as a progressive increase in velocity for all subsequent stages renders the modified 20 MST for ice-sports a reliable and valid test for cardiorespiratory fitness (VO2max), with surface-specific utility. / Dissertation (MA (Human Movement Science))--University of Pretoria, 2005. / Biokinetics, Sport and Leisure Sciences / unrestricted