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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Promoting physical activity among community-dwelling people with acquired brain injury

Tweedy, Sean Michael Unknown Date (has links)
The overall aim of this thesis is to contribute to the development and implementation of evidence-based physical activity promotion strategies for people with acquired brain injury (ABI). A randomized controlled trial (RCT) will furnish the highest level of evidence regarding the efficacy of a given intervention, but the immaturity of this area of research means that, currently, an RCT is not an appropriate research design. Therefore the purpose of the program of research presented in this thesis was to strategically contribute to the evidence base required to justify the conduct of a well designed RCT of an intervention promoting physical activity for people with ABI. By increasing participation in free-living, moderate intensity walking, people with ABI may reduce the oxygen cost of walking, thereby improving everyday functioning. The first study (presented in Chapter 3) evaluated a novel over-ground walking protocol in which a third party assists participants with ABI to reproduce previously self-selected comfortable and brisk walking speeds. Such a protocol could be used in conjunction with a portable indirect calorimetry to evaluate changes in oxygen cost of self-selected walking speeds over time. Thirteen people with ABI and related gait pattern impairment (age 31 + 8 yrs) completed two familiarization and two testing sessions. The first testing session used a self-paced (SP) protocol in which participants walked for 6 minutes at two self-selected speeds – comfortable and brisk paces. The second, conducted one week later, used an externally-paced (EP) protocol in which participants were instructed to walk at the pace indicated by the test administrator, who verbally and visually guided the participant to walk at their previous self-selected comfortable and brisk paces. In each testing session participants wore a portable indirect calorimeter (Cosmed K4b2). Measures obtained were oxygen cost of walking (l.min-1) and distance walked (m). Analysis demonstrated that the EP protocol reproduced distances walked at comfortable and brisk speeds with a high degree of accuracy and that agreement between measures of oxygen cost obtained during the SP and EP protocols were acceptable. Steady-state oxygen uptake is characteristic of a constant workload and was elicited during both EP walking trials, indicating that walking speeds were constant throughout the walk trials. It was concluded that the EP protocol described is a valid means of assisting people with ABI to reproduce overground walking speeds and that the protocol would be useful for evaluating changes in the oxygen cost of those walking speeds that may occur over the course of an intervention. The purpose of the second study (presented in Chapter 4) was to evaluate the validity of a uniaxial accelerometer (MTI Actigraph) for measuring physical activity in people with acquired brain injury (ABI) using portable indirect calorimetry (Cosmed K4b2) as a criterion measure. Fourteen people with ABI and related gait pattern impairment (age 32 + 8 years), wore an MTI Actigraph that measured activity (counts.min-1) and a Cosmed K4b2 that measured oxygen consumption (ml.kg-1.min-1) during four activities – quiet sitting (QS), comfortable paced (CP), brisk paced (BP) and fast paced (FP) walking. MET levels were predicted from Actigraph counts using a published equation and compared with Cosmed measures. Predicted METs for each of the 56 activity bouts (14 participants x four bouts) were classified (light, moderate, vigorous or very vigorous intensity) and compared with Cosmed-based classifications. Results indicated that Actigraph counts provide a valid index of activity across the intensities investigated in this study. For light to moderate activity, Actigraph-based estimates of METs are acceptable for group-level analysis and are a valid means of classifying activity intensity. The Actigraph significantly underestimated higher intensity activity although, in practice, this limitation will have minimal impact on activity measurement of most community-dwelling people with ABI as higher intensity activity is likely to be rare in this group. In the third study (presented in Chapter 5), 18 community-dwelling adults with acquired brain injury and a related gait pattern impairment (32.3 + 7.5 yrs) participated in an 8-week intervention promoting lifestyle physical activity. The aims were threefold: to evaluate the physical and psychosocial effects of the intervention; to assess whether the intervention increased the physical activity of participants; and to qualitatively evaluate the perceived effectiveness and acceptability of the intervention. Data were collected at six time points over 28 weeks: three pre-intervention, one each at 12 weeks prior (T1), 11 weeks prior (T2) and immediately pre-intervention (T3); and three post-intervention at immediately after (T4), four weeks after (T5) and eight weeks after (T6) the intervention. Physical outcomes measured were oxygen cost of comfortable and brisk-paced walking and maximum distance walked in three minutes. Psychosocial outcomes measured were SF-36, Depression Anxiety and Stress Scales (DASS), Rosenberg Self-Esteem Scale (RSES), Satisfaction with Life Scale (SWLS) and the Barriers to Health Activities for Disabled Persons (BHADP). Physical activity was sampled 6 days at T3, T4 and T6 and two measures were obtained – Actigraph counts per day and total minutes of activity greater than or equal to moderate intensity. Semi-structured interviews were used to evaluate the perceived effectiveness and acceptability of the intervention. The intervention comprised weekly, home-based, interactive problem-solving sessions designed to identify and overcome barriers to activity and to promote walking, together with facilitation of a community based leisure activity of the participant’s choice. Results indicated that the intervention improved important aspects of physical and psychosocial health for community-dwelling people with ABI. Compared with mean baseline measures, improvements in oxygen cost of brisk walking and self-esteem occurred that were both clinically and statistically significant at T6 (p < 0.01). Significant changes in two subscales of the SF-36 and the SWLS also occurred, although they were not sustained at T6. Measures of physical activity increased but not to an extent that was statistically significant. Qualitative data were principally positive, with 100% of participants and their significant others indicating they would recommend the program to another person with ABI. Given the particularly low levels of physical activity in the ABI population, and the correspondingly large individual and community benefits of that will be accrued if their physically active behavior can be increased, the promising results from this program of research indicate that there is a strong justification for allocating the resources necessary to conduct a sufficiently powered, randomized controlled trial of a lifestyle physical activity intervention for people with ABI.
22

Promoting physical activity among community-dwelling people with acquired brain injury

Tweedy, Sean Michael Unknown Date (has links)
The overall aim of this thesis is to contribute to the development and implementation of evidence-based physical activity promotion strategies for people with acquired brain injury (ABI). A randomized controlled trial (RCT) will furnish the highest level of evidence regarding the efficacy of a given intervention, but the immaturity of this area of research means that, currently, an RCT is not an appropriate research design. Therefore the purpose of the program of research presented in this thesis was to strategically contribute to the evidence base required to justify the conduct of a well designed RCT of an intervention promoting physical activity for people with ABI. By increasing participation in free-living, moderate intensity walking, people with ABI may reduce the oxygen cost of walking, thereby improving everyday functioning. The first study (presented in Chapter 3) evaluated a novel over-ground walking protocol in which a third party assists participants with ABI to reproduce previously self-selected comfortable and brisk walking speeds. Such a protocol could be used in conjunction with a portable indirect calorimetry to evaluate changes in oxygen cost of self-selected walking speeds over time. Thirteen people with ABI and related gait pattern impairment (age 31 + 8 yrs) completed two familiarization and two testing sessions. The first testing session used a self-paced (SP) protocol in which participants walked for 6 minutes at two self-selected speeds – comfortable and brisk paces. The second, conducted one week later, used an externally-paced (EP) protocol in which participants were instructed to walk at the pace indicated by the test administrator, who verbally and visually guided the participant to walk at their previous self-selected comfortable and brisk paces. In each testing session participants wore a portable indirect calorimeter (Cosmed K4b2). Measures obtained were oxygen cost of walking (l.min-1) and distance walked (m). Analysis demonstrated that the EP protocol reproduced distances walked at comfortable and brisk speeds with a high degree of accuracy and that agreement between measures of oxygen cost obtained during the SP and EP protocols were acceptable. Steady-state oxygen uptake is characteristic of a constant workload and was elicited during both EP walking trials, indicating that walking speeds were constant throughout the walk trials. It was concluded that the EP protocol described is a valid means of assisting people with ABI to reproduce overground walking speeds and that the protocol would be useful for evaluating changes in the oxygen cost of those walking speeds that may occur over the course of an intervention. The purpose of the second study (presented in Chapter 4) was to evaluate the validity of a uniaxial accelerometer (MTI Actigraph) for measuring physical activity in people with acquired brain injury (ABI) using portable indirect calorimetry (Cosmed K4b2) as a criterion measure. Fourteen people with ABI and related gait pattern impairment (age 32 + 8 years), wore an MTI Actigraph that measured activity (counts.min-1) and a Cosmed K4b2 that measured oxygen consumption (ml.kg-1.min-1) during four activities – quiet sitting (QS), comfortable paced (CP), brisk paced (BP) and fast paced (FP) walking. MET levels were predicted from Actigraph counts using a published equation and compared with Cosmed measures. Predicted METs for each of the 56 activity bouts (14 participants x four bouts) were classified (light, moderate, vigorous or very vigorous intensity) and compared with Cosmed-based classifications. Results indicated that Actigraph counts provide a valid index of activity across the intensities investigated in this study. For light to moderate activity, Actigraph-based estimates of METs are acceptable for group-level analysis and are a valid means of classifying activity intensity. The Actigraph significantly underestimated higher intensity activity although, in practice, this limitation will have minimal impact on activity measurement of most community-dwelling people with ABI as higher intensity activity is likely to be rare in this group. In the third study (presented in Chapter 5), 18 community-dwelling adults with acquired brain injury and a related gait pattern impairment (32.3 + 7.5 yrs) participated in an 8-week intervention promoting lifestyle physical activity. The aims were threefold: to evaluate the physical and psychosocial effects of the intervention; to assess whether the intervention increased the physical activity of participants; and to qualitatively evaluate the perceived effectiveness and acceptability of the intervention. Data were collected at six time points over 28 weeks: three pre-intervention, one each at 12 weeks prior (T1), 11 weeks prior (T2) and immediately pre-intervention (T3); and three post-intervention at immediately after (T4), four weeks after (T5) and eight weeks after (T6) the intervention. Physical outcomes measured were oxygen cost of comfortable and brisk-paced walking and maximum distance walked in three minutes. Psychosocial outcomes measured were SF-36, Depression Anxiety and Stress Scales (DASS), Rosenberg Self-Esteem Scale (RSES), Satisfaction with Life Scale (SWLS) and the Barriers to Health Activities for Disabled Persons (BHADP). Physical activity was sampled 6 days at T3, T4 and T6 and two measures were obtained – Actigraph counts per day and total minutes of activity greater than or equal to moderate intensity. Semi-structured interviews were used to evaluate the perceived effectiveness and acceptability of the intervention. The intervention comprised weekly, home-based, interactive problem-solving sessions designed to identify and overcome barriers to activity and to promote walking, together with facilitation of a community based leisure activity of the participant’s choice. Results indicated that the intervention improved important aspects of physical and psychosocial health for community-dwelling people with ABI. Compared with mean baseline measures, improvements in oxygen cost of brisk walking and self-esteem occurred that were both clinically and statistically significant at T6 (p < 0.01). Significant changes in two subscales of the SF-36 and the SWLS also occurred, although they were not sustained at T6. Measures of physical activity increased but not to an extent that was statistically significant. Qualitative data were principally positive, with 100% of participants and their significant others indicating they would recommend the program to another person with ABI. Given the particularly low levels of physical activity in the ABI population, and the correspondingly large individual and community benefits of that will be accrued if their physically active behavior can be increased, the promising results from this program of research indicate that there is a strong justification for allocating the resources necessary to conduct a sufficiently powered, randomized controlled trial of a lifestyle physical activity intervention for people with ABI.
23

Promoting physical activity among community-dwelling people with acquired brain injury

Tweedy, Sean Michael Unknown Date (has links)
The overall aim of this thesis is to contribute to the development and implementation of evidence-based physical activity promotion strategies for people with acquired brain injury (ABI). A randomized controlled trial (RCT) will furnish the highest level of evidence regarding the efficacy of a given intervention, but the immaturity of this area of research means that, currently, an RCT is not an appropriate research design. Therefore the purpose of the program of research presented in this thesis was to strategically contribute to the evidence base required to justify the conduct of a well designed RCT of an intervention promoting physical activity for people with ABI. By increasing participation in free-living, moderate intensity walking, people with ABI may reduce the oxygen cost of walking, thereby improving everyday functioning. The first study (presented in Chapter 3) evaluated a novel over-ground walking protocol in which a third party assists participants with ABI to reproduce previously self-selected comfortable and brisk walking speeds. Such a protocol could be used in conjunction with a portable indirect calorimetry to evaluate changes in oxygen cost of self-selected walking speeds over time. Thirteen people with ABI and related gait pattern impairment (age 31 + 8 yrs) completed two familiarization and two testing sessions. The first testing session used a self-paced (SP) protocol in which participants walked for 6 minutes at two self-selected speeds – comfortable and brisk paces. The second, conducted one week later, used an externally-paced (EP) protocol in which participants were instructed to walk at the pace indicated by the test administrator, who verbally and visually guided the participant to walk at their previous self-selected comfortable and brisk paces. In each testing session participants wore a portable indirect calorimeter (Cosmed K4b2). Measures obtained were oxygen cost of walking (l.min-1) and distance walked (m). Analysis demonstrated that the EP protocol reproduced distances walked at comfortable and brisk speeds with a high degree of accuracy and that agreement between measures of oxygen cost obtained during the SP and EP protocols were acceptable. Steady-state oxygen uptake is characteristic of a constant workload and was elicited during both EP walking trials, indicating that walking speeds were constant throughout the walk trials. It was concluded that the EP protocol described is a valid means of assisting people with ABI to reproduce overground walking speeds and that the protocol would be useful for evaluating changes in the oxygen cost of those walking speeds that may occur over the course of an intervention. The purpose of the second study (presented in Chapter 4) was to evaluate the validity of a uniaxial accelerometer (MTI Actigraph) for measuring physical activity in people with acquired brain injury (ABI) using portable indirect calorimetry (Cosmed K4b2) as a criterion measure. Fourteen people with ABI and related gait pattern impairment (age 32 + 8 years), wore an MTI Actigraph that measured activity (counts.min-1) and a Cosmed K4b2 that measured oxygen consumption (ml.kg-1.min-1) during four activities – quiet sitting (QS), comfortable paced (CP), brisk paced (BP) and fast paced (FP) walking. MET levels were predicted from Actigraph counts using a published equation and compared with Cosmed measures. Predicted METs for each of the 56 activity bouts (14 participants x four bouts) were classified (light, moderate, vigorous or very vigorous intensity) and compared with Cosmed-based classifications. Results indicated that Actigraph counts provide a valid index of activity across the intensities investigated in this study. For light to moderate activity, Actigraph-based estimates of METs are acceptable for group-level analysis and are a valid means of classifying activity intensity. The Actigraph significantly underestimated higher intensity activity although, in practice, this limitation will have minimal impact on activity measurement of most community-dwelling people with ABI as higher intensity activity is likely to be rare in this group. In the third study (presented in Chapter 5), 18 community-dwelling adults with acquired brain injury and a related gait pattern impairment (32.3 + 7.5 yrs) participated in an 8-week intervention promoting lifestyle physical activity. The aims were threefold: to evaluate the physical and psychosocial effects of the intervention; to assess whether the intervention increased the physical activity of participants; and to qualitatively evaluate the perceived effectiveness and acceptability of the intervention. Data were collected at six time points over 28 weeks: three pre-intervention, one each at 12 weeks prior (T1), 11 weeks prior (T2) and immediately pre-intervention (T3); and three post-intervention at immediately after (T4), four weeks after (T5) and eight weeks after (T6) the intervention. Physical outcomes measured were oxygen cost of comfortable and brisk-paced walking and maximum distance walked in three minutes. Psychosocial outcomes measured were SF-36, Depression Anxiety and Stress Scales (DASS), Rosenberg Self-Esteem Scale (RSES), Satisfaction with Life Scale (SWLS) and the Barriers to Health Activities for Disabled Persons (BHADP). Physical activity was sampled 6 days at T3, T4 and T6 and two measures were obtained – Actigraph counts per day and total minutes of activity greater than or equal to moderate intensity. Semi-structured interviews were used to evaluate the perceived effectiveness and acceptability of the intervention. The intervention comprised weekly, home-based, interactive problem-solving sessions designed to identify and overcome barriers to activity and to promote walking, together with facilitation of a community based leisure activity of the participant’s choice. Results indicated that the intervention improved important aspects of physical and psychosocial health for community-dwelling people with ABI. Compared with mean baseline measures, improvements in oxygen cost of brisk walking and self-esteem occurred that were both clinically and statistically significant at T6 (p < 0.01). Significant changes in two subscales of the SF-36 and the SWLS also occurred, although they were not sustained at T6. Measures of physical activity increased but not to an extent that was statistically significant. Qualitative data were principally positive, with 100% of participants and their significant others indicating they would recommend the program to another person with ABI. Given the particularly low levels of physical activity in the ABI population, and the correspondingly large individual and community benefits of that will be accrued if their physically active behavior can be increased, the promising results from this program of research indicate that there is a strong justification for allocating the resources necessary to conduct a sufficiently powered, randomized controlled trial of a lifestyle physical activity intervention for people with ABI.
24

Pseudoephedrine and its effect on performance : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Sport and Exercise Science at Massey University, Palmerston North, New Zealand

Betteridge, Scott Sheng-yi January 2007 (has links)
Pseudoephedrine is a mild stimulant which partially mimics the action of noradrenaline and adrenaline. Recently, pseudoephedrine has been removed from the World Anti Doping Agency (WADA) prohibited substances list. This occurred despite limited research in regards to its effects on sporting performance, and no studies on prolonged exercise performance (>2hrs). There is some evidence to suggest pseudoephedrine may have an ergogenic effect at dosages exceeding therapeutic levels, possibly by masking fatigue. This study investigated the possible ergogenic effects of pseudoephedrine on endurance cycling performance. Using a double blind, randomised cross over design, eight well-trained cyclists (VO2max 69 ± 2 ml×kg-1) performed two self- paced performance time trials at least 6 days apart. Ninety minutes prior to the trial, subjects consumed either placebo or pseudoephedrine (2.5 mg×kg-1) capsules. Diet and exercise were controlled for 48 hrs prior to each trial. The time trial required completion of a set amount of work, equivalent to riding at two and half hours at a power output calculated to elicit 70% VO2 max. Power output was measured using a Powertap system (Cycle Ops Power, Saris Cycling Group, USA). Venous blood samples were collected prior to capsule ingestion, just before starting the trial, and at every 20% increment in completed work until completion and were analysed for glucose and lactate. Heart rate was recorded throughout the trial. There was no significant effect of pseudoephedrine on average performance (p=0.235). Heart rate was significantly higher with pseudoephedrine consumption compared to placebo (p<0.05), but there was no significant difference in glucose or lactate between trials. Pseudoephedrine does not significantly improve self-paced endurance cycling performance, though the individual response was variable. However, exercising heart rate was significantly higher during exercise after ingestion of the stimulant.
25

The physiological effects of pseudoephedrine on endurance cycling : a thesis submitted in the partial fulfilment of the requirements for the degree of Master of Science in Sport and Exercise Science, Massey University (Palmerston North, New Zealand)

Mouatt, Joshua Roger January 2008 (has links)
Background: Pseudoephedrine (PSE) is a mild central nervous system stimulant that when consumed at a high dosage has the potential to alter physiological and psychophysical responses. PSE is widely accessible as over-the-counter medication and despite limited research into PSE at high dosages or its effects on prolonged exercise (>2 hours) is no-longer on the World Anti-Doping Association’s banned substance list. Currently unrestricted in sport and with no real understanding of the abovementioned responses during endurance exercise there is a high potential for abuse in sport. A recent study performed in our laboratory found PSE to improve self-paced cycling performance in some individuals, however no physiological measurements were taken Purpose: The primary purpose of this study was to determine the physiological effects of PSE at a dosage previously shown to improve performance (2.5 mg/kg) in some individuals during prolonged cycling. A secondary purpose of this study was to assess the effect on endurance cycling performance. Methods: In a randomized, double-blind and counter-balanced design, ten welltrained cyclists participated in two trials, consisting of 120 min of fixed-intensity cycling at 65% VO2max followed by a set work, self-paced time-trial (TT) of ~30 min, following ingestion of either 2.5 mg/kg PSE or visual-matched glucose placebo. Venous blood samples were collected before and during exercise, along with body temperatures and heart rate. Perceived effort and expired gas samples were collected during exercise. Exercise and diet was controlled ~48-hours prior to the trials. Results: Mean heart rate was significantly higher with PSE (P = 0.028) during fixed-intensity exercise. Blood glucose concentrations were significantly lower with PSE (P <0.001) for the first 40 min of fixed-intensity exercise. Respiratory exchange ratio was lower in the final 20-min of fixed-intensity and TT with PSE. Blood lactate, perceived effort, ventilation, and body temperatures were not significantly different between conditions during exercise, nor was TT performance; however individual response was variable. Conclusions: PSE ingestion increased heart rate during endurance cycling and initially suppressed carbohydrate release into the bloodstream while increasing fat oxidation in the later stages of exercise. Despite individual responses, endurance cycling performance remained unchanged with PSE ingestion.
26

The physiological and molecular response to repeated sprints in male and female team-sport athletes : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Sport and Exercise Science at Massey University, Palmerston North, New Zealand

Dent, Jessica January 2009 (has links)
Background: Due to the unique demands of the sport, athletes playing football perform a variety of differing training methods to improve physiological performance. These include strength, endurance and sprint training. While the effects of strength and endurance training have been well researched, the effects of repeated-sprint training on blood and muscle variables in well trained males and females are not well known. An understanding of changes to the blood and muscle during and following an exercise bout are important, so to gain an understanding of the type of stress and resulting adaptations that may occur. Also, while a large volume of research in training adaptations has been performed on males; little has been done on females. To date, some research indicates metabolism during moderateintensity exercise may differ between males and females; however, no study has compared repeated-sprint exercise. Therefore, it is unclear as to whether males and females would have a differing physiological response to repeated-sprint training. Purpose: The purpose of this study was to determine the effects of a repeated-sprint bout on molecular signalling in muscle and blood measures and heart rate in well-trained footballers. Additionally, we compared running times and sprint decrement (%). Research Design: Eight female senior University football players (Mean ± SD, age, 19 ± 1 y, VO ? 2peak 53.0 ± 5.1 ml·kg-1min-1) and seven male senior University football players (Mean ± SD, age, 19 ± 3 y, VO ? 2peak 59.0 ± 6.6 ml·kg-1min-1) volunteered to participate in this study. Participants performed four bouts of 6 x 30 m maximal sprints spread equally over a 40 min period. Sprint time was measured (at 30 m) for each sprint and sprint decrement was also calculated for all bouts. Muscle biopsies were taken from the vastus lateralis muscle at rest, 15 min following exercise and 2 h into recovery. Venous blood samples were taken at the same time points as the biopsies while capillary blood lactate was measured at rest and 3 min following each sprint bout. Repeated measures ANOVA and Post hoc t-tests were performed to determine significant differences between the two groups (male vs. female) and time points. Findings: Both groups had a significant (P<0.05) increase in blood lactate (mM) after the first bout of repeated sprints, with no differences between females (pre 0.9 ± 0.4 mM – post 10.0 ± 1.6 mM) and males (pre 0.8 ± 0.3 mM – post 10.0 ± 3.5 mM). Blood lactate remained elevated compared to rest (P<0.05) following bouts 2, 3 and 4 for both females (12.0 ± 3.6, 12.0 ± 3.3, 12.2 ± 3.8 mM respectively) and males (11.9 ± 2.9, 11.6 ± 2.3, 11.5 ± 4.0 mM respectively), with no differences between groups or time points (P>0.05). There were no differences (P>0.05) between the female and male athletes in mean heart rate attained at the end of each bout of repeated sprints (187 ± 2 v 190 ± 2 bpm respectively) or during recovery between sprints (140 ± 2 v 130 ± 2 bpm respectively). There were no differences between groups or time points in blood insulin (P>0.05). Fastest 30 m sprint time and mean 30 m sprint time during the repeated-sprint bout was faster for the males than females (4.58 ± 0.12 v 5.26 ± 0.27 s respectively; (P>0.05)). However, there were no differences in running velocity during the sprints between the males and females (165 ± 0.4 % vs. 155 ± 0.05 %; P>0.05) when expressed relative to velocity at VO ? 2peak (vVO ? 2peak). Also, mean % decrement during the repeated-sprint bout was lower in the males then females (4.9 ± 1.3 v 7.1 ± 1.9 % respectively; P<0.05). No changes were observed in total or phosphorylated Akt at any time-point or between genders. However, while total 4E-BP1 was lower, the ratio of total to phosphoryalated 4E-BP1 at rest was greater in males than females (P<0.05). Finally, there was also a significant decrease in 4E-BP1 phosphorylation post-exercise in males (P<0.05), but not females. Conclusions: There were no sex differences in blood lactate or heart rate throughout the repeated-sprint bout. These findings suggest that there were no cardio respiratory or lactate production/clearance differences in the response to a repeated-sprint-training bout between sexes. However, while males were faster than their female counterparts, the average relative speed was similar between sexes, suggesting a similar relative volume of work was performed during the sprint bouts. However, the females did have a greater decrement in sprint performance indicating a greater ability to recover sprint performance in the males. Sex differences in resting total and phosphorylated 4E-BP1 may indicate greater potential for muscle growth in the male athletes during basal conditions. However, differences could be due to factors other than sex, including previous training history. There was a lack of change in plasma insulin or Akt, but, similar to resistance exercise, a significant decrease in post-exercise 4E-BP1 phosphorylation for the males, but not females. The sex differences in the 4E-BP1 phosphorylation response post-exercise could be due to differences in the metabolic disturbance in the muscle during and following maximal sprints. Keywords: blood lactate, heart rate, muscle
27

The development of a reliable and valid netball intermittent activity test : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Sport and Exercise Science at Massey University, Auckland, New Zealand

Ryan, Helen Joanne January 2009 (has links)
The purpose of the present investigation was to identify the exercise intensity of netball match play in order to assist in the development of a Netball Intermittent Activity Test (NIAT). A further aim was to assess the criterion validity and the test-retest reliability of the NIAT. Eleven female netball players (21.4 ± 3.1 years, 1.73 ± 0.06 m, 69.3 ± 5.3 kg and 48.4 ± 4.9 ml•kg-1•min–1 mean ± SD, age, height, body mass and VO2max, respectively) volunteered to participate in the study. Heart rate data was recorded for all participants from at least two full 60 minute games during Premier Club competition. Individual maximum heart rate values were acquired for all subjects from the performance of the Multistage Fitness Test, and used to transform heart rate recordings into percent maximum heart rate (%HRmax). Patterns in %HRmax were used to indicate positional grouping when developing the NIAT from time motion analysis data. Subjects performed two trials of the NIAT separated by at least seven days. Physiological and performance markers were measured systematically throughout the NIAT. Exercise intensity as denoted by %HRmax significantly decreased from the first half of match play to the second half (90.4 ± 2.7% v 88.3 ± 2.8%; p<0.05). Significant differences (p<0.05) were observed between positional groups and led to the grouping of Defence (D), Centre Court (CC), and Attack (A) players for NIAT performance. Comparisons of %HRmax between match play and NIAT performance indicated that the NIAT had good criterion validity for D (match Mdn = 92.52% vs. NIAT Mdn = 86.27%, p>0.05) and A (match Mdn = 86.95% vs. NIAT Mdn = 82.93%, p>0.05) players, but that %HRmax during the NIAT (Mdn = 79.70%) was significantly lower than match play (Mdn = 89.70%) for CC group (p<0.05). Measures of 5 m sprint performance (1.27 ± 0.06 s v 1.25 ± 0.06 s; p>0.05; r=0.66, p<0.001), vertical jump height (29.12 ± 4.17 cm v 28.82 ± 3.60 cm; p>0.05; r=0.91, p<0.001), circuit time (107.49 ± 3.22 s v 107.89 ± 4.27 s; p>0.05; r=0.72, p>0.001) and %HRmax (82.56 ± 4.66% v 81.03 ± 4.13%; p>0.05; r=0.82, p<0.001) for NIAT1 vs. NIAT2 indicated good test-retest reliability. These data suggest that netball players experience a reduction in exercise intensity over the duration of a game, with exercise intensity being related to on-court position. Whilst the NIAT appears to be a repeatable activity pattern, it is not a good simulation of physiological strain for all positional groups. More work is required in order to create a netball simulation that is both reliable and valid for all players.
28

Performance, physiological, and perceptual effects of wearing graduated compression stockings during running : a thesis presented in partial fulfilment of the requirements for a degree of Master of Science in Sport and Exercise Science at Massey University, Auckland, New Zealand

Creasy, Robert January 2008 (has links)
Purpose: The aims of these studies were to examine the effects of wearing different grades of graduated compression stockings (GCS) on performance, physiological, and perceptual measures before, during, and after exercise in well-trained runners. Method: Two separate running studies were conducted where participants wore different grades of GCS compared with a placebo control stocking in random, counter-balanced order: (1) a field study focussed on a series of 10-km running performances on a 400m track; (2) a laboratory study that examined the effects of 40-min treadmill running on physiological, perceptual, and muscle function responses. Changes in muscle function and damage were determined pre- and post-run by measuring creatine kinase (CK) and myoglobin (Mb) concentrations, counter-movement jump (CMJ) height, muscle soreness, and pressure sensitivity. Physiological measurements of heart rate (HR), oxygen uptake (V&O2), blood lactate concentration [La], and ratings of perceived exertion (RPE) were measured during running. Pre- and post-run perceptual scales assessed comfort, tightness and pain associated with wearing GCS. Results: There were no significant differences in 10-km run time, mean HR, V&O2, [La], and RPE for participants wearing different GCS in (1) and (2) (P<0.05). Con and Low were rated most comfortable (P<0.05) and Hi were tightest (P<0.05) and induced more pain (P<0.05) when GCS were compared in both studies. CMJ was better in participants wearing Low and Med GCS post-run compared with Con in (1) and for Con and all GCS at 0 h post-exercise in (2). CK and Mb levels were higher (P<0.05) and pressure sensitivity was more pronounced (P<0.05) at 0 h post-run for Con and all GCS (2). Few participants (4/10) reported muscle soreness at any one location in (2). Conclusions: Well-trained runners did not experience improved performance, physiological, or perceptual responses when wearing different grades of GCS during 10- km track or 40 min treadmill running compared with a control garment. 40 min treadmill running at 80% V&O2 max may not be strenuous enough to elicit a loss of muscle function in well-trained runners. Runners felt more comfortable wearing GCS that had less compression.
29

The physiological effects of pseudoephedrine on endurance cycling : a thesis submitted in the partial fulfilment of the requirements for the degree of Master of Science in Sport and Exercise Science, Massey University (Palmerston North, New Zealand)

Mouatt, Joshua Roger January 2008 (has links)
Background: Pseudoephedrine (PSE) is a mild central nervous system stimulant that when consumed at a high dosage has the potential to alter physiological and psychophysical responses. PSE is widely accessible as over-the-counter medication and despite limited research into PSE at high dosages or its effects on prolonged exercise (>2 hours) is no-longer on the World Anti-Doping Association’s banned substance list. Currently unrestricted in sport and with no real understanding of the abovementioned responses during endurance exercise there is a high potential for abuse in sport. A recent study performed in our laboratory found PSE to improve self-paced cycling performance in some individuals, however no physiological measurements were taken Purpose: The primary purpose of this study was to determine the physiological effects of PSE at a dosage previously shown to improve performance (2.5 mg/kg) in some individuals during prolonged cycling. A secondary purpose of this study was to assess the effect on endurance cycling performance. Methods: In a randomized, double-blind and counter-balanced design, ten welltrained cyclists participated in two trials, consisting of 120 min of fixed-intensity cycling at 65% VO2max followed by a set work, self-paced time-trial (TT) of ~30 min, following ingestion of either 2.5 mg/kg PSE or visual-matched glucose placebo. Venous blood samples were collected before and during exercise, along with body temperatures and heart rate. Perceived effort and expired gas samples were collected during exercise. Exercise and diet was controlled ~48-hours prior to the trials. Results: Mean heart rate was significantly higher with PSE (P = 0.028) during fixed-intensity exercise. Blood glucose concentrations were significantly lower with PSE (P <0.001) for the first 40 min of fixed-intensity exercise. Respiratory exchange ratio was lower in the final 20-min of fixed-intensity and TT with PSE. Blood lactate, perceived effort, ventilation, and body temperatures were not significantly different between conditions during exercise, nor was TT performance; however individual response was variable. Conclusions: PSE ingestion increased heart rate during endurance cycling and initially suppressed carbohydrate release into the bloodstream while increasing fat oxidation in the later stages of exercise. Despite individual responses, endurance cycling performance remained unchanged with PSE ingestion.
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The physiological effects of pseudoephedrine on endurance cycling : a thesis submitted in the partial fulfilment of the requirements for the degree of Master of Science in Sport and Exercise Science, Massey University (Palmerston North, New Zealand)

Mouatt, Joshua Roger January 2008 (has links)
Background: Pseudoephedrine (PSE) is a mild central nervous system stimulant that when consumed at a high dosage has the potential to alter physiological and psychophysical responses. PSE is widely accessible as over-the-counter medication and despite limited research into PSE at high dosages or its effects on prolonged exercise (>2 hours) is no-longer on the World Anti-Doping Association’s banned substance list. Currently unrestricted in sport and with no real understanding of the abovementioned responses during endurance exercise there is a high potential for abuse in sport. A recent study performed in our laboratory found PSE to improve self-paced cycling performance in some individuals, however no physiological measurements were taken Purpose: The primary purpose of this study was to determine the physiological effects of PSE at a dosage previously shown to improve performance (2.5 mg/kg) in some individuals during prolonged cycling. A secondary purpose of this study was to assess the effect on endurance cycling performance. Methods: In a randomized, double-blind and counter-balanced design, ten welltrained cyclists participated in two trials, consisting of 120 min of fixed-intensity cycling at 65% VO2max followed by a set work, self-paced time-trial (TT) of ~30 min, following ingestion of either 2.5 mg/kg PSE or visual-matched glucose placebo. Venous blood samples were collected before and during exercise, along with body temperatures and heart rate. Perceived effort and expired gas samples were collected during exercise. Exercise and diet was controlled ~48-hours prior to the trials. Results: Mean heart rate was significantly higher with PSE (P = 0.028) during fixed-intensity exercise. Blood glucose concentrations were significantly lower with PSE (P <0.001) for the first 40 min of fixed-intensity exercise. Respiratory exchange ratio was lower in the final 20-min of fixed-intensity and TT with PSE. Blood lactate, perceived effort, ventilation, and body temperatures were not significantly different between conditions during exercise, nor was TT performance; however individual response was variable. Conclusions: PSE ingestion increased heart rate during endurance cycling and initially suppressed carbohydrate release into the bloodstream while increasing fat oxidation in the later stages of exercise. Despite individual responses, endurance cycling performance remained unchanged with PSE ingestion.

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