Thesis (Ph. D.)--Oregon State University, 1995. Includes bibliographical references (leaves 91-92... more Thesis (Ph. D.)--Oregon State University, 1995. Includes bibliographical references (leaves 91-92). Microfiche. s
The Journal of sports medicine and physical fitness, 2002
Recently, there has been an increase in popularity and participation in the sport of snowshoeing.... more Recently, there has been an increase in popularity and participation in the sport of snowshoeing. While the sport has gained considerable recognition, to date there is little or no scientific research regarding training responses to snowshoeing as a form of exercise. Therefore, the purpose of this study was to determine whether snowshoe training could improve fitness measures. A further purpose was to compare responses from a snowshoe training program to a similarly designed run training program. This prospective, comparative study was conducted with healthy males and females between the ages of 19 and 24. These subjects were recruited from the University of Vermont population and surrounding community. Following baseline measurements in VO2max, running time to exhaustion (RTE), and anthropometry, 17 subjects (10 snowshoers and 7 runners) participated in a six week conditioning program. Both groups exercised for 30 min at 75-85% age predicted maximum heart rate, 3-4 times per week, ...
Individuals undergoing an unaccustomed exercise bout incorporating a high degree of eccentric mus... more Individuals undergoing an unaccustomed exercise bout incorporating a high degree of eccentric muscle contractions commonly experience delayed onset muscle soreness. The damage manifests itself via tenderness, loss of strength, swelling, elevated muscle enzyme activity and loss of flexibility. Following an initial "damage bout," a repeated bout results in reduced symptoms. This protective effect is known as the repeated bout effect (RBE) and can last up to 24 weeks between bouts. The mechanism for this RBE is unclear and both central and local mechanisms have been suggested. In an attempt to test the central hypothesis, 12 subjects (mean age = 22.5± 4yrs, ht = 167±9cm, mass = 71.5±13.5kg) underwent an exercise protocol whereby one leg was exercised eccentrically and following complete recovery; the contralateral leg was exercised in the same manner. Subjects were required to step on and off a 46-cm step for 20 minutes at a cadence of 15 steps/minute. One leg was used to go ...
ATP repletion following exhaustive exercise is approximated to be 90-95% complete in 3 minutes, a... more ATP repletion following exhaustive exercise is approximated to be 90-95% complete in 3 minutes, and is crucial in the performance of short duration, high intensity work. Few studies appear to have used this 3-minute interval in the investigation of recovery modes, blood lactate accumulation and power output. Thus, our aim was to investigate changes in peak power (PP), average power (AP) and blood lactate during repeated bouts of high intensity, short duration cycling, comprising active and passive recovery modes lasting 3 minutes. Seven male cyclists (age 21.8±3.3 yrs, mass 73.0±3.8kgs, height 177.3±3.4cm) performed both an active (3 min at 80rpm & 1kg resistance) and a passive recovery (no work between bouts) protocol. Following a warm-up, subjects performed six 15-second maximal sprints against a fixed workload of 5.5kg. Mean PP across the six trials was 775±11.2Watts (W) and 772±33.4W for active and passive protocols respectively; whereas mean AP was 671±26.4W and 664±10.0W, resp...
We examined whether passive stiffness of an eccentrically exercising muscle group affects the sub... more We examined whether passive stiffness of an eccentrically exercising muscle group affects the subsequent symptoms of muscle damage. Passive hamstring muscle stiffness was measured during an instrumented straight-leg-raise stretch in 20 subjects (11 men and 9 women) who were subsequently classified as "stiff" (N = 7), "normal" (N = 6), or "compliant" (N = 7). Passive stiffness was 78% higher in the stiff subjects (36.2 +/- 3.3 N.m.rad(-1)) compared with the compliant subjects (20.3 +/- 1.8 N.m.rad(-1)). Subjects then performed six sets of 10 isokinetic (2.6 rad.s(-1)) submaximal (60% maximal voluntary contraction) eccentric actions of the hamstring muscle group. Symptoms of muscle damage were documented by changes in isometric hamstring muscle strength, pain, muscle tenderness, and creatine kinase activity on the following 3 days. Strength loss, pain, muscle tenderness, and creatine kinase activity were significantly greater in the stiff compared with th...
The ratings of perceived exertion (RPE) scale has received widespread acceptance for gaining a su... more The ratings of perceived exertion (RPE) scale has received widespread acceptance for gaining a subjective estimate of work intensity and as a means of monitoring and regulating exercise intensity across a variety of populations. The original premise for the use of the scale was its high correlation with heart rate (HR). Although individual correlations between HR and RPE in individuals on beta-blocker therapy are probably as high as in untreated individuals, there is evidence to suggest that the RPE response is mediated at a given work rate, particularly at higher absolute work rates. The variation in the RPE response appears to be mediated by the type of beta-blocker therapy administered. In the interests of safety it is necessary for the exercise specialist to develop at least a basic understanding of the mechanism and effects of beta-blocker therapy as they relate to exercise prescription. beta-Blocking drugs cause a decrease in HR and cardiac output at rest and during exercise, a decrease in myocardial contractility and a decrease in coronary and muscle blood flow. These effects can initiate premature fatigue and apprehension in the exercising patient. In the light of these responses, the RPE scale provides important information and may be used to increase the accuracy of monitoring and the prescription of exercise intensity in the cardiac population. While results regarding the use and accuracy of the scale during beta-blocker treatment are equivocal, this appears to be due mainly to variations in dosage of the drug, the mode, intensity and duration of exercise and the health status of the individuals used. Overall, the RPE scale appears to be an appropriate monitoring tool, particularly when it is used after a learning period. It is concluded that nonselective beta-blockade therapy increases RPE, particularly localised RPE. This could be attributed to a decreased blood flow and oxygen delivery to the muscle and altered glycolytic metabolism, which increases local muscle fatigue. There is no evidence to suggest a decrease in the total level of oxygen consumption at given work rates. However, as beta-blocker therapy reduces the maximal oxygen consumption (VO2max) attainable, this serves to increase the exercise intensity at all work rates. Thus, for a given absolute work rate, the RPE response is higher. However, when the work rate is expressed as a proportion of the VO2max attainable during beta-blockade, the differences in RPE are minimised or disappear. Although the evidence is not conclusive, it appears that cardioselective beta-blocker therapy does not have such profound effects on the RPE response, compared with nonselective beta-blocker therapy, when this is expressed as a proportion of VO2max. However, localised RPE tends to be higher for nonselective beta-blocker therapy. Thus, the evidence indicates that RPE can be used to estimate exercise intensity, provided the specific effects of the type of beta-blocker therapy on local and central fatigue (and local and central RPE) are taken into account. Studies which have examined the effects of an endurance training programme during beta-blocker therapy have shown that RPE are decreased at given work rates after training. This has been observed for cardioselective and nonselective beta-blocker therapy, and local and central RPE. There is also some evidence to suggest that the RPE can be used as the controlling variable to regulate the exercise response. Patients on cardioselective beta-blocker therapy produce similar exercise intensities to other cardiac patients who are not receiving beta-blocker treatment.
Sports Medicine, Training and Rehabilitation, 1996
The purpose of this study was to evaluate the reliability of the rating of perceived exertion (Bo... more The purpose of this study was to evaluate the reliability of the rating of perceived exertion (Borg's RPE scale) in patients with and without coronary heart disease (CHD). Eighteen subjects, nine with CHD and nine controls, underwent two submaximal cycle ergometer tests. The CHD patient group had a mean age of 63.11 ± 6.64 years and a mean body mass
The purpose of this study was to examine psychological affect at different ratings of perceived e... more The purpose of this study was to examine psychological affect at different ratings of perceived exertion (RPE) in 15 high- and 15 low-active women. Both groups performed three steady-state exercise bouts on a cycle ergometer at RPEs 9, 13, and 17 and reported their affect in the last 20 sec. of and 5 min. after each work rate. There were no differences between groups in percentage of maximal oxygen uptake (% VO2max) at each RPE. Low-active women reported feeling significantly more negative at RPE 17 than RPE 9 and less positive than the high-active women at RPEs 9, 13, and 17. In addition, all subjects reported more positive feelings 5 min. postexercise than in the last 20 sec. of exercising, especially at RPE 17. These results have implications for exercise prescription in groups differing in habitual activity levels.
ABSTRACT The purpose of this study was to investigate the effects of an application of suncream o... more ABSTRACT The purpose of this study was to investigate the effects of an application of suncream on mean skin temperature (MST), rectal temperature (Tre), oxygen consumption and heart rate during exercise in the heat. Twenty-two male subjects underwent two steady state exercise tests (55% of maximum oxygen consumption, mean work rate 153 watts) for 40 minutes (following a 5 minute warm-up), under two treatment conditions at the same ambient temperature (32 degrees C, 54% relative humidity). One treatment involved wearing an application of suncream (SC) while the other treatment did not (NSC). Suncream was applied in the amount of 30 ml/m2 of body surface area. Results of this study indicated that an application of suncream significantly reduced MST, on average. 31 degrees C, during exercise in the heat (p = 0.03). However, further statistical analysis revealed that this was a function of a significant interaction effect (p = 0.001) (main effect is sunscreen; interaction effect sunscreen plus temperature). MST was lower for the SC condition versus NSC over all time measurements. Results also showed a significant difference in the mean core to skin temperature gradient (p = 0.001), with a greater gradient existing in the SC condition. There did not appear to be any effect of suncream on ventilation, rectal temperature, oxygen consumption, lactate levels, sweat loss, percent plasma volume change, rating of perceived exertion, or respiratory exchange ratio. Interestingly, although not statistically significant (p = 0.18), rectal temperature remained lower, on average 0.1 degree C, under the SC condition for every measurement throughout the exercise session. In conclusion, results of this preliminary study suggest that an application of suncream does not impair heat dissipation as indicated by a decreased MST and increased core to skin thermal gradient.
Medicine & Science in Sports & Exercise, 1997
ATP repletion following exhaustive exercise is approximated to be 98-99% complete in 3 mins and i... more ATP repletion following exhaustive exercise is approximated to be 98-99% complete in 3 mins and is crucial in the performance of short duration, high intensity work. To our knowledge few studies appear to have used this 3 min interval in the investigation of ...
ABSTRACT The aim of this study was to compare the effects of 8 days of vitamin C (VC) supplementa... more ABSTRACT The aim of this study was to compare the effects of 8 days of vitamin C (VC) supplementation on elbow flexor delayed onset muscle soreness (DOMS) to 8 days of placebo ingestion. For 3 days prior to an exercise bout (2 x 20 eccentric elbow extensions), and for 5 days after, a treatment group ingested 3 x 1000 mg/day of VC versus 3 x 50 mg/day of glucose ingestion for the placebo group over the same time period. All subjects were prescreened via dietary recall to exclude any subjects with habitual VC consumption greater than 400 mg/day. Subject comprised 24 subjects (male and female) randomly divided into 2 groups of 12 subjects. Treatment group comprised 5 females and placebo group comprised 8 females. Data from a repeated measures ANOVA indicate that DOMS was successfully induced in both groups via significant time effects for strength loss (P = 0.0001), point tenderness (P = 0.0001), elbow flexor decreased range of motion (P = 0.013), and subjective pain (P = 0.0001). However, there were no significant between group differences in response to any of the aforementioned variables: strength loss (P = 0.202), point tenderness (P = 0.824), elbow flexor range of motion (P = 0.208), subjective pain (P = 0.342). The results of this study suggest that a VC supplementation protocol of 3 x 1000 mg/day for 8 days is ineffective in protecting against selected markers of DOMS.
Thesis (Ph. D.)--Oregon State University, 1995. Includes bibliographical references (leaves 91-92... more Thesis (Ph. D.)--Oregon State University, 1995. Includes bibliographical references (leaves 91-92). Microfiche. s
The Journal of sports medicine and physical fitness, 2002
Recently, there has been an increase in popularity and participation in the sport of snowshoeing.... more Recently, there has been an increase in popularity and participation in the sport of snowshoeing. While the sport has gained considerable recognition, to date there is little or no scientific research regarding training responses to snowshoeing as a form of exercise. Therefore, the purpose of this study was to determine whether snowshoe training could improve fitness measures. A further purpose was to compare responses from a snowshoe training program to a similarly designed run training program. This prospective, comparative study was conducted with healthy males and females between the ages of 19 and 24. These subjects were recruited from the University of Vermont population and surrounding community. Following baseline measurements in VO2max, running time to exhaustion (RTE), and anthropometry, 17 subjects (10 snowshoers and 7 runners) participated in a six week conditioning program. Both groups exercised for 30 min at 75-85% age predicted maximum heart rate, 3-4 times per week, ...
Individuals undergoing an unaccustomed exercise bout incorporating a high degree of eccentric mus... more Individuals undergoing an unaccustomed exercise bout incorporating a high degree of eccentric muscle contractions commonly experience delayed onset muscle soreness. The damage manifests itself via tenderness, loss of strength, swelling, elevated muscle enzyme activity and loss of flexibility. Following an initial "damage bout," a repeated bout results in reduced symptoms. This protective effect is known as the repeated bout effect (RBE) and can last up to 24 weeks between bouts. The mechanism for this RBE is unclear and both central and local mechanisms have been suggested. In an attempt to test the central hypothesis, 12 subjects (mean age = 22.5± 4yrs, ht = 167±9cm, mass = 71.5±13.5kg) underwent an exercise protocol whereby one leg was exercised eccentrically and following complete recovery; the contralateral leg was exercised in the same manner. Subjects were required to step on and off a 46-cm step for 20 minutes at a cadence of 15 steps/minute. One leg was used to go ...
ATP repletion following exhaustive exercise is approximated to be 90-95% complete in 3 minutes, a... more ATP repletion following exhaustive exercise is approximated to be 90-95% complete in 3 minutes, and is crucial in the performance of short duration, high intensity work. Few studies appear to have used this 3-minute interval in the investigation of recovery modes, blood lactate accumulation and power output. Thus, our aim was to investigate changes in peak power (PP), average power (AP) and blood lactate during repeated bouts of high intensity, short duration cycling, comprising active and passive recovery modes lasting 3 minutes. Seven male cyclists (age 21.8±3.3 yrs, mass 73.0±3.8kgs, height 177.3±3.4cm) performed both an active (3 min at 80rpm & 1kg resistance) and a passive recovery (no work between bouts) protocol. Following a warm-up, subjects performed six 15-second maximal sprints against a fixed workload of 5.5kg. Mean PP across the six trials was 775±11.2Watts (W) and 772±33.4W for active and passive protocols respectively; whereas mean AP was 671±26.4W and 664±10.0W, resp...
We examined whether passive stiffness of an eccentrically exercising muscle group affects the sub... more We examined whether passive stiffness of an eccentrically exercising muscle group affects the subsequent symptoms of muscle damage. Passive hamstring muscle stiffness was measured during an instrumented straight-leg-raise stretch in 20 subjects (11 men and 9 women) who were subsequently classified as "stiff" (N = 7), "normal" (N = 6), or "compliant" (N = 7). Passive stiffness was 78% higher in the stiff subjects (36.2 +/- 3.3 N.m.rad(-1)) compared with the compliant subjects (20.3 +/- 1.8 N.m.rad(-1)). Subjects then performed six sets of 10 isokinetic (2.6 rad.s(-1)) submaximal (60% maximal voluntary contraction) eccentric actions of the hamstring muscle group. Symptoms of muscle damage were documented by changes in isometric hamstring muscle strength, pain, muscle tenderness, and creatine kinase activity on the following 3 days. Strength loss, pain, muscle tenderness, and creatine kinase activity were significantly greater in the stiff compared with th...
The ratings of perceived exertion (RPE) scale has received widespread acceptance for gaining a su... more The ratings of perceived exertion (RPE) scale has received widespread acceptance for gaining a subjective estimate of work intensity and as a means of monitoring and regulating exercise intensity across a variety of populations. The original premise for the use of the scale was its high correlation with heart rate (HR). Although individual correlations between HR and RPE in individuals on beta-blocker therapy are probably as high as in untreated individuals, there is evidence to suggest that the RPE response is mediated at a given work rate, particularly at higher absolute work rates. The variation in the RPE response appears to be mediated by the type of beta-blocker therapy administered. In the interests of safety it is necessary for the exercise specialist to develop at least a basic understanding of the mechanism and effects of beta-blocker therapy as they relate to exercise prescription. beta-Blocking drugs cause a decrease in HR and cardiac output at rest and during exercise, a decrease in myocardial contractility and a decrease in coronary and muscle blood flow. These effects can initiate premature fatigue and apprehension in the exercising patient. In the light of these responses, the RPE scale provides important information and may be used to increase the accuracy of monitoring and the prescription of exercise intensity in the cardiac population. While results regarding the use and accuracy of the scale during beta-blocker treatment are equivocal, this appears to be due mainly to variations in dosage of the drug, the mode, intensity and duration of exercise and the health status of the individuals used. Overall, the RPE scale appears to be an appropriate monitoring tool, particularly when it is used after a learning period. It is concluded that nonselective beta-blockade therapy increases RPE, particularly localised RPE. This could be attributed to a decreased blood flow and oxygen delivery to the muscle and altered glycolytic metabolism, which increases local muscle fatigue. There is no evidence to suggest a decrease in the total level of oxygen consumption at given work rates. However, as beta-blocker therapy reduces the maximal oxygen consumption (VO2max) attainable, this serves to increase the exercise intensity at all work rates. Thus, for a given absolute work rate, the RPE response is higher. However, when the work rate is expressed as a proportion of the VO2max attainable during beta-blockade, the differences in RPE are minimised or disappear. Although the evidence is not conclusive, it appears that cardioselective beta-blocker therapy does not have such profound effects on the RPE response, compared with nonselective beta-blocker therapy, when this is expressed as a proportion of VO2max. However, localised RPE tends to be higher for nonselective beta-blocker therapy. Thus, the evidence indicates that RPE can be used to estimate exercise intensity, provided the specific effects of the type of beta-blocker therapy on local and central fatigue (and local and central RPE) are taken into account. Studies which have examined the effects of an endurance training programme during beta-blocker therapy have shown that RPE are decreased at given work rates after training. This has been observed for cardioselective and nonselective beta-blocker therapy, and local and central RPE. There is also some evidence to suggest that the RPE can be used as the controlling variable to regulate the exercise response. Patients on cardioselective beta-blocker therapy produce similar exercise intensities to other cardiac patients who are not receiving beta-blocker treatment.
Sports Medicine, Training and Rehabilitation, 1996
The purpose of this study was to evaluate the reliability of the rating of perceived exertion (Bo... more The purpose of this study was to evaluate the reliability of the rating of perceived exertion (Borg's RPE scale) in patients with and without coronary heart disease (CHD). Eighteen subjects, nine with CHD and nine controls, underwent two submaximal cycle ergometer tests. The CHD patient group had a mean age of 63.11 ± 6.64 years and a mean body mass
The purpose of this study was to examine psychological affect at different ratings of perceived e... more The purpose of this study was to examine psychological affect at different ratings of perceived exertion (RPE) in 15 high- and 15 low-active women. Both groups performed three steady-state exercise bouts on a cycle ergometer at RPEs 9, 13, and 17 and reported their affect in the last 20 sec. of and 5 min. after each work rate. There were no differences between groups in percentage of maximal oxygen uptake (% VO2max) at each RPE. Low-active women reported feeling significantly more negative at RPE 17 than RPE 9 and less positive than the high-active women at RPEs 9, 13, and 17. In addition, all subjects reported more positive feelings 5 min. postexercise than in the last 20 sec. of exercising, especially at RPE 17. These results have implications for exercise prescription in groups differing in habitual activity levels.
ABSTRACT The purpose of this study was to investigate the effects of an application of suncream o... more ABSTRACT The purpose of this study was to investigate the effects of an application of suncream on mean skin temperature (MST), rectal temperature (Tre), oxygen consumption and heart rate during exercise in the heat. Twenty-two male subjects underwent two steady state exercise tests (55% of maximum oxygen consumption, mean work rate 153 watts) for 40 minutes (following a 5 minute warm-up), under two treatment conditions at the same ambient temperature (32 degrees C, 54% relative humidity). One treatment involved wearing an application of suncream (SC) while the other treatment did not (NSC). Suncream was applied in the amount of 30 ml/m2 of body surface area. Results of this study indicated that an application of suncream significantly reduced MST, on average. 31 degrees C, during exercise in the heat (p = 0.03). However, further statistical analysis revealed that this was a function of a significant interaction effect (p = 0.001) (main effect is sunscreen; interaction effect sunscreen plus temperature). MST was lower for the SC condition versus NSC over all time measurements. Results also showed a significant difference in the mean core to skin temperature gradient (p = 0.001), with a greater gradient existing in the SC condition. There did not appear to be any effect of suncream on ventilation, rectal temperature, oxygen consumption, lactate levels, sweat loss, percent plasma volume change, rating of perceived exertion, or respiratory exchange ratio. Interestingly, although not statistically significant (p = 0.18), rectal temperature remained lower, on average 0.1 degree C, under the SC condition for every measurement throughout the exercise session. In conclusion, results of this preliminary study suggest that an application of suncream does not impair heat dissipation as indicated by a decreased MST and increased core to skin thermal gradient.
Medicine & Science in Sports & Exercise, 1997
ATP repletion following exhaustive exercise is approximated to be 98-99% complete in 3 mins and i... more ATP repletion following exhaustive exercise is approximated to be 98-99% complete in 3 mins and is crucial in the performance of short duration, high intensity work. To our knowledge few studies appear to have used this 3 min interval in the investigation of ...
ABSTRACT The aim of this study was to compare the effects of 8 days of vitamin C (VC) supplementa... more ABSTRACT The aim of this study was to compare the effects of 8 days of vitamin C (VC) supplementation on elbow flexor delayed onset muscle soreness (DOMS) to 8 days of placebo ingestion. For 3 days prior to an exercise bout (2 x 20 eccentric elbow extensions), and for 5 days after, a treatment group ingested 3 x 1000 mg/day of VC versus 3 x 50 mg/day of glucose ingestion for the placebo group over the same time period. All subjects were prescreened via dietary recall to exclude any subjects with habitual VC consumption greater than 400 mg/day. Subject comprised 24 subjects (male and female) randomly divided into 2 groups of 12 subjects. Treatment group comprised 5 females and placebo group comprised 8 females. Data from a repeated measures ANOVA indicate that DOMS was successfully induced in both groups via significant time effects for strength loss (P = 0.0001), point tenderness (P = 0.0001), elbow flexor decreased range of motion (P = 0.013), and subjective pain (P = 0.0001). However, there were no significant between group differences in response to any of the aforementioned variables: strength loss (P = 0.202), point tenderness (P = 0.824), elbow flexor range of motion (P = 0.208), subjective pain (P = 0.342). The results of this study suggest that a VC supplementation protocol of 3 x 1000 mg/day for 8 days is ineffective in protecting against selected markers of DOMS.
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