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This dissertation encompassed three studies involving precision pinch strength and 5% submaximal fine-motor control. One hundred participants (30-79 years old) were divided into 10-year categories, with 10 males and 10 females in each decade. A Manual Force Quantification System containing a platform and force-transducer apparatus, along with a computer and visual monitor, was used. Each subject performed four tasks -- maximal voluntary isometric contraction (MVIC), force-matching, tracing, and tracking -- by applying force on the transducers with the thumb and index finger while attempting to produce a desired force level or task displayed on the computer monitor. The first study measured MVIC, accuracy (rRMSE, Root Mean Square Relative Error), and force variability (Coefficient of Variation, CV) during a 5% MVIC force-matching task. The second study measured accuracy (rRMSE), task time, and group variability during a 5% MVIC tracing task. The third study measured accuracy and group variability during a 5% MVIC tracking task. Tracing and tracking were each divided into six Segments (S1-S6), three of which (S1-S3) required the increasing application of force from 50g up to 5% MVIC and the remaining three (S4-S6) requiring a release of force from MVIC down to 1% MVIC. The force-matching and force-tracking task times were scaled to each participant's MVIC, while the tracing task was performed at the participant's self-selected speed. The participants were encouraged to be accurate but also to trace the target line as quickly as possible. Declines in precision pinch strength and force control began to occur in the 70s for easier force-control tasks and in their 60s for more advanced force-tracking tasks. Men were stronger than women at all age levels. Participants in their 30s were the fastest; those in their 40s, 50s, and 60s slowed down to be accurate; and those in their 70s moved faster but were the least accurate. Three segmental factors affected error and time: low force level, releasing as opposed to applying force, and location along the target line with respect to reversal or ending points. Finally, variables for females were more heterogeneous at earlier decades than for men, and the older the age group was, the greater the variable heterogeneity was.

<p> Exercise intensity is one of the major factors determining the utilization of carbohydrates (CHO) and lipids in mammalian skeletal muscle. Using indirect calorimetry, we determined maximal oxygen uptake (VO2max) and whole-body rates of CHO and lipid oxidation in rats selectively bred for high and low running capacity (HCR's and LCR's) during exercise at 50, 60, 70 and 80%VO2max. Previous studies have revealed a pattern of selection where mammals with different aerobic capacities use the same proportions of lipids and CHO when exercising at the same relative exercise intensity and as intensity increases, CHO use increases and lipid use decreases. The present results showed that the HCR's had a VO2max and distance run to exhaustion that was 1.3 and 4.0 times greater than the LCR's respectively. Also, both groups of rats followed the pattern of fuel selection seen in previous studies where the same proportions (in%) of lipids and CHO are used at the same relative exercise intensity. On an absolute scale, the HCR's used more lipids and CHO than the LCR's at all exercise intensities but the results were not always statistically significant. We also determined the exercise intensity that elicited the greatest lipid use to be 60% VO2max in both groups.</p> <p> In order to explain these patterns of fuel selection, metabolic indicators, metabolites and enzymes, in skeletal muscle were measured at rest and post exercise for one hour at 60%VO2max. Specifically, ATP and phosphocreatine (PCr) metabolite concentrations were determined in the medial and lateral gastrocnemius, extensor digitorum longus (EDL), tibialis anterior (TA), and soleus muscle. The medial gastrocnemius and soleus were analyzed (pre and post exercise samples were combined) for their oxidative and glycolytic enzyme activity by measuring citrate synthase (CS), cytochrome oxidase (COX), β-hydroxyacyl CoA dehydrogenase (HOAD), and lactate dehydrogenase (LDH) . PCr and ATP concentrations did not change pre and post exercise and between the HCR's and LCR's except for the EDL where there was a significant decrease (P<0.05) in both metabolites after exercise in both groups of rats. For the enzyme measurements, CS and COX activities were higher (P<0.05) in the HCR's for the soleus and HOAD activities were also higher in the HCR's medial gastrocnemius compared to the LCR's. We concluded that the HCR's have a greater oxidative capacity as shown by their greater aerobic and endurance capacity (VO2max and distance to exhaustion), their ability to oxidize a greater absolute amount of lipids and CHO's at the same relative exercise intensity, and their higher activities of oxidative enzymes in the soleus (CS and COX) and medial gastrocnemius (HOAD). Future research into the mechanisms involved in explaining these patterns of fuel selection may include examining fatty acid transport proteins, fatty acid and CHO availability, fiber types, and catecholamines.</p> / Thesis / Master of Science (MSc)

Falls in people aged over 65 years account for the largest proportion of all injury-related deaths and hospitalisations within Australia. Falls contributed to 1,000 deaths and 50,000 hospitalisations in older people during 1998 (Commonwealth Department of Health and Aged Care 2001). It has been predicted that by 2016, 16% of the Australian population will be aged over 65 years (Australian Bureau of Statistics 1999) placing considerable pressure on the health care system. Furthermore, prospective studies have shown that 30-50% of people aged 65 years and over, will experience a fall (Tinetti et al. 1988b; Campbell et al. 1989; Lord et al. 1994b; Hill 1999; Brauer et al. 2000; Stalenhoef et al. 2002) and this figure increases exponentially with age (Lord et al. 1994b). Many physiological falls risk factors have been established including reduced leg strength, poor balance, impaired vision, slowed reaction time and proprioception deficits. However, little research has been conducted to determine whether performance on aerobic fitness tasks is also a physiological falls risk factor. Aerobic fitness has previously been related to an individual's ability to perform activities of daily living, which in turn has been linked to falls. It was therefore proposed that aerobic fitness might also be a risk factor for falls among community dwelling older people. This research aimed to provide clinical evidence to inform public health practice. This thesis comprised of four objectives: the first to find suitable measures of aerobic fitness for older people; the second investigated relationships between existing clinical tests and future falls; the third explored relationships between aerobic fitness tests and future falls; the final objective was to examine the independent relationships between falls and clinical and physiological characteristics. The participants were recruited through a random sample from the local electoral roll, with an average age of 73 ±6 years. Of the 87 participants who completed the prospective component of the study, 37% were male and 63% were female. Sixty-three participants (65%) reported no previous falls, 19 (20%) reported a single fall, and 16 (15%) reported two or more falls in the previous 12 months. The first objective required participants recruited from the community to take part in submaximal and maximal fitness tests in order to find suitable measures of aerobic fitness. A further objective was to determine whether older people were able to fulfil the 'standard' criteria for completion of a maximum oxygen consumption test. The measures used in this research included: maximum oxygen consumption, peak oxygen consumption, ventilatory threshold, oxygen uptake kinetics, oxygen deficit, efficiencies, oxygen consumption at zero, 30 and 50 watts, predicted max and Six-Minute Walk Test distance. Only weak relationships were observed between submaximal aerobic measures and peak oxygen consumption. Furthermore, only 54% of participants were able to fulfil the criteria to complete a test of maximum oxygen consumption, indicating it was not a suitable measure for use among a sample of community dwelling older people. Therefore submaximal aerobic variables were used in the following chapters. The second objective investigated the relationship between clinical measures and falls among older people and was carried out to enable comparisons between the population in this study and those described in the literature. This research found that the Timed Up and Go (TUG) test was the most sensitive of all clinical tests (including the Berg Balance Scale, Function Reach, Performance Oriented Mobility Assessment and Physiological Profile Assessment) for the assessment of future falls. The TUG requires participants to stand up, walk 3m, turn, walk back, and sit down. Time taken to complete the test is the recorded value. For this study, a cut-off value of 7-seconds was established, above which individuals were at increased risk of falls. Previous research suggested cut-off times of over 10s were appropriate for older people. However, this is the first study to assess falls prospectively and definitively find that the TUG can discriminate between future fallers and non-fallers. This research also investigated the differences in falls risk factors for functionally different subsamples, as defined by their ability to undertake and complete the cycle test. The participants who could complete the test had significantly better balance ability and strength than those unable to undertake or complete the cycle test. However, this inability to undertake or complete the cycle test was not itself a predictor of future falls. These two groups also differed in the relationships between clinical test results and falls risk. Participants in the no-cycle group had very similar results to that of the entire cohort. Even after adjustment for age, the TUG, foot and hand reaction times and knee flexion strength were all performed better by non-fallers than fallers. However, none of these differed between fallers and non-fallers for participants in the cycle group. This group had better balance ability and strength than the no-cycle group. These results indicated that the cycle group differed from the no-cycle group and the entire sample, further indicating that factors other than the physiological variables measured in this research influence falls risk in strong participants with good balance ability. Similar results were reported when aerobic tests and falls were investigated in the third objective. In the whole sample, the fallers walked significantly less distance than non-fallers for the 6-MWT. Similar results were found for participants in the no-cycle group but not the cycle group. All participants were able to complete the Six-Minute Walk Test (6-MWT) although only 74% were able to undertake and complete the cycle test. The fourth objective was to consider all measures from the previous chapters as potential predictors of falls. The variables most predictive of future falls were the TUG and having experienced one or more falls in the previous 12 months. As a result they could be used as screening tools for the identification of high-risk fallers who require referral for further assessment. This could be completed by a General Practitioner or Practice Nurse, which would ensure that screening is being undertaken in the wider population. If the patient is at high risk they should be referred for falls risk factor assessment to determine an optimal tailored intervention to reduce future falls. Low risk patients should be referred for preventive evidence-based activities. These steps can potentially improve quality of life for individuals, and if effective in preventing future falls, will result in reduced costs to the individual and the Australian public. The results of this work demonstrate that the best screening tests are simple tasks like the TUG and asking an individual if they have experienced a fall in the last 12 months. This research also found that strong, mobile older people who could undertake and complete a submaximal cycle ergometer test, still experienced falls in the following 12 months, although the causes of this are currently unknown. This research showed that physiological falls risk factors are less relevant as these highly functional older people do not have physiological deficits. However, this research found that the 6-MWT showed promise as a predictor of falls in a group who could not complete a submaximal cycle ergometer test, who had lower strength, balance and functional fitness scores than a group who could complete this cycle test. The results showed that physiological falls risk factors are still very important for older people with lower physical abilities, and this is where aerobic fitness may still be related to falls. While the association between aerobic fitness and falls remains unclear, these are novel and provocative findings highlighting the need for future falls risk investigations to consider aerobic fitness as a contributing factor.

BAKGRUND: Fysisk aktivitet har påvisats ha en positiv effekt på de områden i hjärnan som är kopplade till inlärning och minne. Dock är det oklart hur stor påverkan en individs fysiska kapacitetsnivå har på dessa områden. SYFTE: Syftet med studien var att undersöka ifall en intervention i form av fysisk aktivitet kan påverka arbetsminnet, och ifall en grupp individer presterar annorlunda på ett arbetsminnestest efter interventionen beroende på deras syreupptagningsförmåga. METOD: Studien hade en kvantitativ och kvasiexperimentell design utan kontrollgrupp. En grupp om 33 kvinnor, åldern 20-30 år utförde testet som bestod utav minnestestet Letter-number sequencing task före och efter 10 minuters intervention i form av submaximal ergometercykling. Samtidigt som interventionen beräknades individernas maximala syreupptagningsförmåga med hjälp av Åstrands cykelergometertest. Beroende av resultatet på cykelergometertestet delades testpersonerna in i två grupper som representerade hög/mycket hög (grupp 1) syreupptagningsförmåga respektive låg/genomsnittlig (grupp 2) syreupptagningsförmåga. RESULTAT: Medianvärdet på LNS innan interventionen var 20,5 för grupp 1 (n=20) respektive 21 för grupp 2 (n=13). Detta medianvärde förbättrades med en enhet för båda grupperna vid LNS efter interventionen. Skillnaden inom gruppresultaten före och efter interventionen var icke-signifikant med ett P-värde på 0,614 för grupp 1 och 0,891 för grupp 2. Skillnaden i förändring mellan grupperna var heller ej signifikant med ett P-värde på 0,854. KONKLUSION: Arbetsminnet påverkades inte av 10 minuters fysisk aktivitet i någon av gruppjämförelserna. En individs syreupptagningsförmåga verkar heller inte påverka arbetsminnet. / BACKGROUND: Physical activity has been shown to have a positive effect on the areas of the brain connected to learning and memory. Even so, it is uncertain how much a person’s level of physical capacity influences these areas. OBJECTIVES: The purpose of the study was to examine if an intervention of physical activity could affect working memory, and whether a group of people perform differently during a working memory test after the intervention depending on their oxygen uptake. METHODS: The study had a quantitive and quasiexperimental design without control group. A group of 33 women, 20-30 years of age, conducted the test which consisted of the memory test Letter-number sequencing task before and after 10 minutes of submaximal ergometer cycling. During the intervention the individual’s maximal oxygen uptake was calculated with the Åstrand cycle ergometer test. Depending on the results from the cycle ergometer test, the testsubjects was split into two groups which represented high/very high (group 1) oxygen uptake and low/average (group 2) oxygen uptake. RESULTS: The median of LNS before the intervention was 20,5 for group 1 (n=20) and 21 for group 2 (n=13). This median improved with one unit for both groups at LNS after the intervention. The difference between the results within the groups before and after the intervention proved to be non-significant with a P-value of 0,614 for group 1 and 0,891 for group 2. The difference in change between the groups was neither significant with a P-value of 0,854. CONCLUSION: Working memory was not affected of 10 minutes of physical activity in neither of the comparison between the groups. It also seems that an individual’s oxygen uptake doesn’t affect working memory.

BAKGRUND: Fysisk aktivitet har påvisats ha en positiv effekt på de områden i hjärnan som är kopplade till inlärning och minne. Dock är det oklart hur stor påverkan en individs fysiska kapacitetsnivå har på dessa områden. SYFTE: Syftet med studien var att undersöka ifall en intervention i form av fysisk aktivitet kan påverka arbetsminnet, och ifall en grupp individer presterar annorlunda på ett arbetsminnestest efter interventionen beroende på deras syreupptagningsförmåga. METOD: Studien hade en kvantitativ och kvasiexperimentell design utan kontrollgrupp. En grupp om 33 kvinnor, åldern 20-30 år utförde testet som bestod utav minnestestet Letter-number sequencing task före och efter 10 minuters intervention i form av submaximal ergometercykling. Samtidigt som interventionen beräknades individernas maximala syreupptagningsförmåga med hjälp av Åstrands cykelergometertest. Beroende av resultatet på cykelergometertestet delades testpersonerna in i två grupper som representerade hög/mycket hög (grupp 1) syreupptagningsförmåga respektive låg/genomsnittlig (grupp 2) syreupptagningsförmåga. RESULTAT: Medianvärdet på LNS innan interventionen var 20,5 för grupp 1 (n=20) respektive 21 för grupp 2 (n=13). Detta medianvärde förbättrades med en enhet för båda grupperna vid LNS efter interventionen. Skillnaden inom gruppresultaten före och efter interventionen var icke-signifikant med ett P-värde på 0,614 för grupp 1 och 0,891 för grupp 2. Skillnaden i förändring mellan grupperna var heller ej signifikant med ett P-värde på 0,854. KONKLUSION: Arbetsminnet påverkades inte av 10 minuters fysisk aktivitet i någon av gruppjämförelserna. En individs syreupptagningsförmåga verkar heller inte påverka arbetsminnet. / BACKGROUND: Physical activity has been shown to have a positive effect on the areas of the brain connected to learning and memory. Even so, it is uncertain how much a person’s level of physical capacity influences these areas. OBJECTIVES: The purpose of the study was to examine if an intervention of physical activity could affect working memory, and whether a group of people perform differently during a working memory test after the intervention depending on their oxygen uptake. METHODS: The study had a quantitive and quasiexperimental design without control group. A group of 33 women, 20-30 years of age, conducted the test which consisted of the memory test Letter-number sequencing task before and after 10 minutes of submaximal ergometer cycling. During the intervention the individual’s maximal oxygen uptake was calculated with the Åstrand cycle ergometer test. Depending on the results from the cycle ergometer test, the testsubjects was split into two groups which represented high/very high (group 1) oxygen uptake and low/average (group 2) oxygen uptake. RESULTS: The median of LNS before the intervention was 20,5 for group 1 (n=20) and 21 for group 2 (n=13). This median improved with one unit for both groups at LNS after the intervention. The difference between the results within the groups before and after the intervention proved to be non-significant with a P-value of 0,614 for group 1 and 0,891 for group 2. The difference in change between the groups was neither significant with a P-value of 0,854. CONCLUSION: Working memory was not affected of 10 minutes of physical activity in neither of the comparison between the groups. It also seems that an individual’s oxygen uptake doesn’t affect working memory.

In order to address the long-term complications that arise from poor venous return, a hallmark of the Fontan physiology, we assessed the feasibility of a non-invasive, home therapy that will improve the health of the patient during the heart transplant waiting period and ameliorate the quality of life. In order to achieve this goal we tested a device that applies pressure to the lower extremities of the body (legs and abdomen) in a pulsating fashion with the goal of augmenting systemic blood flow to the pulmonary arteries. This treatment will enhance flow from the great veins and through the lungs and serve as adjunctive clinical treatment of single ventricle physiology. The specific aim of this study was to show improvements in cardiorespiratory measurements after applying external pressure as a proxy for improved health in the Fontan patient. Various studies have shown the impaired exercise capacity of post-operative Fontan patients, but very little data exists focusing on a period much later after the surgery. Our results among the two subjects completed so far have shown a moderately beneficial improvement in exercise capacity after the compression therapy. Subjects performed a treadmill exercise stress test at VCU that was followed by six days of applied external pressure treatment and finished with a final post-treatment stress test. Cardiorespiratory data was collected and analyzed for improvements from base level. Overall an improvement in exercise duration time, VO2 peak, ventilatory threshold, and OUES was observed, with only VE / VCO2 slope having mixed results. Both subjects seem to be relatively healthy Fontan patients, as indicated by their VO2 peak, VE/VCO2 slope and OUES. As a result, benefits of treatment may vary among a cohort of Fontan patients with poor health condition; a failing Fontan physiology for instance. The improvement in exercise capacity suggests that this therapy could be very beneficial to Fontan patients. These results warrants follow up studies to explore the extent of the clinical benefits of compression treatment among the Fontan population.

Syfte Syftet är att undersöka Per-Olof och Irma Åstrands tillvägagångssätt vid skapandet av det submaxirnala cykelergometertest som kallas "Åstrandstestet" samt att reflektera övertestets validitet och reliabilitet. Metod Studien är baserad på litteraturstudier samt en djupintervju med Per-Olof Åstrand. Samtal har förts med Sture Malmgren, en av författarna till boken Konditionstest på cykel samt med Per-Olof Åstrand för att undvika oklarheter. Resultat Vårt huvudfynd visar att vid den ursprungliga utformningen och framtagningen av det submaximala cykelergometertest som kallas Åstrandstestet, genomfördes flera submaximala tester där resultaten från försökspersonernas första test exkluderades. Alla personer som testas submaximalt med hjälp av Åstrandstestet så som det används idag, då resultaten från det första testet används, kan få ett felaktigt värde, I dagsläget finns inga studier som visar hur stort felet kan bli eftersom olika människor påverkas olika av exempelvis nervositet. Därför är det svårt för författarna till detta examensarbete att bedöma vilken betydelse exkluderingen av det första testet har för testets noggrannhet. Slutsats Om Åstrandstestet ska användas som metod för att uppskatta en persons maximala syreupptagningsförmåga är det av största vikt att det används på ett sätt som minskar felmarginalerna. För att uppnå detta bör man låta försökspersonen göra ett förtest för att vänja sig vid metod, utrustning och försöksledare.

Abstract Aim: The purpose of the study is to show the influence of Proton Pump Inhibitors (PPI in form of esomeprazole) on the bioactivation of dietary nitrate (sodium-nitrate solution) in submaximal exercise, through affecting the gastric pH. Method: Randomized, doubled-blinded, placebo-controlled and crossover study with six subjects (mean ± SD, age 29 ± 5years, height 170 ± 5 centimeters, weight 70 ± 5 Kg, BMI 24,36 ± 1,75 Kg/m2 blood pressure 119/ 77 ± 6 mmHg, 3 male and 3 female). They were tested in two different trials. Every trial consisted of two parts. One part was cycling on 4 different submaximal stages (80W/60RPM, 80W/90RPM, 120W/60RPM, 120W/90RPM) for 5 minutes each, with 90 minutes rest in between. The same protocol was repeated. In the beginning of the resting time a sodium nitrate solution (NaNO3-, 10mg/kg body weight) was ingested. VO2, VCO2, RER, VE, Lactate, Glucose, heart rate and blood pressure were recorded. Venous blood samples were taken. Whether esomeprazole (10mg) or a placebo were taken 24h, 12h and directly before being tested in both trials. Subjects were pleased to have a nitrate poor diet starting when taking the pills. An information sheet was provided. Results: No significant differences were found between the post values and the treatment. Tendencies of a higher oxygen consumption when taking esomeprazole (2,62%) in comparison to placebo (0,11%) were observed. Systolic BP decreased by 3,91% with the placebo while it decreased just 2,04% with esomeprazole after intake. Sex-specific differences occurred in the metabolism of esomeprazole and dietary nitrate. RER showed a significant post nitrate difference between the female and male participants with t=.006 and a significance in predietary nitrate intake. VE in female (40,79 ± 7,20 L/min) and (50,03 ± 10,09 L/min) in male were as well significant (t=.017). Conclusion: Tendencies of effects of PPI are seen in the post-values of VO2 and BP after intake of dietary nitrate. Gender-differences are shown in RER and VE. More research is needed to see the impact of dietary nitrate on the human body under submaximal load.

Background: Physiologic functional capacity through maximal oxygen uptake (V̇O2max) can be measured in many different ways depending on sport and qualities needed to be assessed.In handball a demanding 3000 meter (m) running test is used to evaluate V̇O2max. If this test is sport specific or if it could be replaced by a less strenuous test is unknown. Aim: The aim ofthis study was to compare performance on 3000-meter running with predicted V̇O2max from a submaximal treadmill jogging test (SMTJ) and performance of the Yo-Yo intermittentrecovery test 1 (IR1). Methods: Male handball players (n = 12) performed the 3000 m running test, the Submaximal Treadmill Jogging test and the Yo-Yo Intermittent Recovery test level 1. Measurements in seconds (s), ml ∙ kg-1 ∙ min-1 and meters where collected and correlated using Pearson r, interclass correlation. Results: A strong significant linear correlation (p &lt; 0.01) was found between performance in 3000 m running (s) and Yo-Yo IR1 performance (m), r = - 0.724 (r2 = 0.524). A weak, not significant linear correlation (p &gt; 0.05)was found between performance in 3000 m running (s) and predicted V̇O2max from submaximal treadmill test (ml ∙ kg-1 ∙ min-1), r = - 0.309 (r2 = 0.095). Conclusion: According to this study the 3000 m running test could be replaced by the Yo-Yo IR1 test or vice versa in adolescent male handball players. The submaximal treadmill test used in this study had several potential errors in estimating V̇O2max, this is probably the reason why only a weak correlation was found between the SMTJ and the 3000 m running test.