Peter Tiidus - Academia.edu (original) (raw)
Papers by Peter Tiidus
Gait & Posture, 2005
Most individuals can use different movement and muscle recruitment patterns to perform a stated t... more Most individuals can use different movement and muscle recruitment patterns to perform a stated task but often only one pattern is selected which optimizes an unknown global objective given the individual's neuromusculoskeletal characteristics. Patients with fibromyalgia syndrome (FS), characterized by their chronic pain, reduced physical work capacity and muscular fatigue, could exhibit a different control signature compared to asymptomatic control volunteers (CV). To test this proposal, 22 women with FS, and 11 CV, were assessed in a gait analysis laboratory. Each subject walked repeatedly at self-selected slow, comfortable, and fast walking speeds. The gait analysis provided, for each walk, each subject's stride time, length, and velocity, and ground reaction force, and lower extremity joint kinematics, moments and powers. The data were then anthropometrically scaled and velocity normalized to reduce the influence of subject mass, leg length, and walking speed on the measured gait outcomes. Similarities and differences in the two groups' scaled and normalized gait patterns were then determined. Results show that FS and CV walk with externally similar stride lengths, times, and velocities, and joint angles and ground reaction forces but they use internally different muscle recruitment patterns. Specifically, FS preferentially power gait using their hip flexors instead of their ankle plantarflexors. Interestingly, CV use a similar muscle fatiguing recruitment pattern to walk fast which parallels the common complaint of fatigue reported by FS walking at comfortable speed. # addresses: pierryn@mcmaster.ca (M.R. Pierrynowski), ptiidus@wlu.ca (P.M. Tiidus), galeav@mcmaster.ca (V. Galea). 1
Canadian journal of physiology and pharmacology, Jan 30, 2015
This study examined the effects of a delay in post-ovariectomy replacement of 17β-estradiol (estr... more This study examined the effects of a delay in post-ovariectomy replacement of 17β-estradiol (estrogen) on the post-exercise proliferation of muscle satellite cells. Nine-week-old, ovariectomized, female Sprague-Dawley rats (n = 64) were distributed among 8 groups based on estrogen status (0.25 mg estrogen pellet or sham), exercise status (90 min run at 17 m·min(-1) and a grade of -13.5° or unexercised), and estrogen replacement ("proximal", estrogen replacement within 2 weeks; or "delayed", estrogen replacement at 11 weeks following ovariectomy). Significant increases in satellite cells were found in the soleus and white gastrocnemius muscle (immunofluorescent colocalization of nuclei with Pax7) 72 h following eccentric exercise (p < 0.05) in all exercised groups. Proximal E2 replacement resulted in a further augmentation of muscle satellite cells in exercised rats (p < 0.05) relative to the delayed estrogen replacement group. Expression of PI3K was unalter...
Journal of sports science & medicine, 2004
Massage therapy is commonly used following endurance running races with the expectation that it w... more Massage therapy is commonly used following endurance running races with the expectation that it will enhance post-run recovery of muscle function and reduce soreness. A limited number of studies have reported little or no influence of massage therapy on post-exercise muscle recovery. However, no studies have been conducted in a field setting to assess the potential for massage to influence muscle recovery following an actual endurance running race. To evaluate the potential for repeated massage therapy interventions to influence recovery of quadriceps and hamstring muscle soreness, recovery of quadriceps and hamstring muscle strength and reduction of upper leg muscle swelling over a two week recovery period following an actual road running race. Twelve adult recreational runners (8 male, 4 female) completed a half marathon (21.1 km) road race. On days 1,4, 8, and 11 post-race, subjects received 30 minutes of standardized massage therapy performed by a registered massage therapist on...
Journal of sports science & medicine, 2002
This field study examined the influence of moderate intensity training on gait patterns and work ... more This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS). FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness of mild exercise on work capacity and gait patterns in FS patients. Participants were 14 females (age 47.0 ± 7.6 y) who participated in a 10 wk community based aerobic, strength and stretching program designed for FS individuals. Subjects were evaluated pre- and post-program and at a 2 month follow up. Work capacity was estimated by a sub-maximal PWC 170 cycle ergometer test and a Borg perceived exertion scale. Gait was assessed using OptoTrack three dimensional kinematics with 16 channel analogu...
Journal of sports science & medicine, 2003
The influence of gender on aerobic energy expenditure (EE) during weight training has not been sy... more The influence of gender on aerobic energy expenditure (EE) during weight training has not been systematically researched. We determined the absolute and relative EE during the performance of two weight training programs of different intensities, durations and total work in males and females. Eight male and seven female recreational weight trainers (20-29 y) completed two randomly ordered weight training sessions involving 2 sets of 8 standard upper and lower body lifts at a set cadence separated by 45 seconds rest between sets and lifts (48 hrs apart). Heavy (H) at 100% 8 Repetition Maximum (8RM), 8 reps, ~19 min duration and light (L) at 85% 8RM, 15 reps, ~23 min duration. VO2 was determined continuously throughout the training sessions. Lean body mass (LBM) was estimated from skin fold measures and body weight. Energy expenditure was estimated from breath-by-breath metabolic measurements using portable metabolic assessment equipment (Cosmed K4b(2)). Absolute EE (total kJ) and rate...
Physiotherapy Canada, 2008
To evaluate the effectiveness of muscle rehabilitation modalities, it is first necessary to devel... more To evaluate the effectiveness of muscle rehabilitation modalities, it is first necessary to develop a model to test measures that would assess physiological, sensory, and functional muscle recovery. This study attempted to develop such a model for wrist injury. Healthy male and female adults (n = 25). SUBJECTS performed wrist muscle damage assessment, soreness, discomfort, difficulty, and functional motor task tests before and 1, 2, and 7 days after eccentric wrist muscle contractions. Wrist-related motor task tests, including the perception of discomfort and difficulty during performance, were also conducted. At 24 hours post-eccentric exercises, wrist extension and flexion force declined (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) and soreness (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) and circumference (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) increased; all returned to normal by 7 days post-exercise. At 24 and 48 hours post-exercise, perception of discomfort and difficulty was elevated during performance of motor tasks (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The completion speed of motor tasks was unaffected at any time post-eccentric exercise (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). Loss of wrist muscle force, increased soreness, task discomfort, and difficulty were noted following eccentric exercise. However, subjects appeared able to compensate, such that the speed of completion of motor tasks was not slowed. Longer or more specific motor tasks may be necessary to mimic real work performance decrement and recovery.
Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstétrique et gynécologie du Canada : JOGC, 2003
To design Canadian guidelines advising obstetric care providers of the maternal, fetal, and neona... more To design Canadian guidelines advising obstetric care providers of the maternal, fetal, and neonatal implications of aerobic and strength-conditioning exercises in pregnancy. Knowledge of the impact of exercise on maternal, fetal, and neonatal morbidity, and of the maternal measures of fitness. MEDLINE search from 1966 to 2002 for English-language articles related to studies of maternal aerobic and strength conditioning in a previously sedentary population, maternal aerobic and strength conditioning in a previously active population, impact of aerobic and strength conditioning on early and late pregnancy outcomes, and impact of aerobic and strength conditioning on neonatal outcomes, as well as for review articles and meta-analyses related to exercise in pregnancy. The evidence collected was reviewed by the Society of Obstetricians and Gynaecologists of Canada (SOGC Clinical Practice Obstetrics Committee) with representation from the Canadian Society for Exercise Physiology, and quan...
European Journal of Applied Physiology and Occupational Physiology, 1999
Estrogen has been shown to reduce post-exercise skeletal muscle damage. Exercise-induced muscle d... more Estrogen has been shown to reduce post-exercise skeletal muscle damage. Exercise-induced muscle damage may be a factor in the elevated post-exercise expression of heat-shock proteins (HSPs). Thus, the present investigation was conducted in order to examine the influence of estrogen on post-exercise levels of HSP 72 and heat-shock cognate, HSC 73, in male and female rodents. Prior to an acute bout of treadmill running, male and female Sprague-Dawley rats received daily injections of either 40 microg x kg(-1) of beta-estradiol 3-benzoate or olive oil vehicle for 2 weeks. A two- to fourfold reduction in post-exercise HSP 72 content was observed in the heart, liver, lung and red and white vastus muscles of estradiol-treated males compared with their vehicle-injected counterparts (P < 0.05). Compared to the males, the females had significantly lower post-exercise HSP 72 levels which were not affected by estradiol supplementation. Moreover, estradiol administration in male rodents resulted in a HSP response similar to that of females following exercise. Thus, the results of the present investigation suggest that estrogen is the factor responsible for the observed differences in post-exercise HSP 72 levels between males and females.
Medicine & Science in Sports & Exercise, 2002
Vitamin E supplementation may confer a protective effect against eccentrically biased exercise-in... more Vitamin E supplementation may confer a protective effect against eccentrically biased exercise-induced muscle damage through stabilization of the cell membrane and possibly via inhibition of free radical formation. Evidence supporting a protective role of vitamin E after contraction-induced muscle injury in humans is, however, inconsistent. The present study sought to determine the effect of vitamin E supplementation on indices of exercise-induced muscle damage and the postexercise inflammatory response after performance of repeated eccentric muscle contractions. Young healthy men performed a bout of 240 maximal isokinetic eccentric muscle contractions (0.52 rad.s-1) after being supplemented for 30 d with either vitamin E (N = 9; 1200 IU.d-1) or placebo (N = 7; safflower oil). Measurements of torque (isometric and concentric) decreased (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.05) below preexercise values immediately post- and at 48 h post-exercise. Biopsies taken 24 h postexercise showed a significant increase in the amount of extensive Z-band disruption (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.01); however, neither the torque deficit nor the extent of Z-band disruption were affected by vitamin E. Exercise resulted in increased macrophage cell infiltration (P = 0.05) into muscle, which was also unaffected by vitamin E. Serum CK also increased as a result of the exercise (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.05) with no effect of vitamin E. We conclude that vitamin E supplementation (30 d at 1200 IU.d-1), which resulted in a 2.8-fold higher serum vitamin E concentration (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.01), had no affect on indices of contraction-induced muscle damage nor inflammation (macrophage infiltration) as a result of eccentrically biased muscle contractions.
IUBMB Life, 1996
MyoD is a myogenic transcription factor responsible for skeletal muscle differentiation during de... more MyoD is a myogenic transcription factor responsible for skeletal muscle differentiation during development. Muscle antioxidant enzyme status was determined in transgenic MyoD deactivated mice. While catalase activity was significantly (P<0.05) elevated in soleus and extensor digitorum longus muscles from MyoD deactivated mice, superoxide dismutase and glutathione peroxidase activities were not. While this may imply a greater propensity for inherent oxidative stress, soleus glutathione status was similar between MyoD deactivated mouse and control soleus muscles. Catalase activity is localized primarily in peroxisomes. Therefore elevated catalase activity may also indicate the presence of factors associated with peroxisome proliferation in muscles from MyoD gene-inactivated mice.
Canadian journal of sport sciences = Journal canadien des sciences du sport, 1989
The reported 7-day dietary intake is described for 60 middle-aged and older middle-class adults a... more The reported 7-day dietary intake is described for 60 middle-aged and older middle-class adults aged 45-75 years. The 30 men, who apparently were mostly still moderately active (reported average energy intake for 7-day recording period 11.7 +/- 3.6 MJ/day) showed few deficiencies in the intake of key nutrients relative to standard dietary recommendations. The 30 women were relatively inactive (reported average energy intake 8.1 +/- 1.9 MJ/day). In consequence, some of them had less than an optimal intake of vitamin A, riboflavin and thiamin, while 25 of 60 subjects (17 women, 8 men) had a calcium intake of less than 800 mg/day. Calcium intake was quite closely correlated to total energy intake. Given that a low level of physical activity was apparently responsible for the failure to meet recommended dietary allowances, an increase of habitual physical activity may thus be commended as a simple approach to the optimisation of diet in the sedentary and economically comfortable older a...
Gait & Posture, 2005
Most individuals can use different movement and muscle recruitment patterns to perform a stated t... more Most individuals can use different movement and muscle recruitment patterns to perform a stated task but often only one pattern is selected which optimizes an unknown global objective given the individual's neuromusculoskeletal characteristics. Patients with fibromyalgia syndrome (FS), characterized by their chronic pain, reduced physical work capacity and muscular fatigue, could exhibit a different control signature compared to asymptomatic control volunteers (CV). To test this proposal, 22 women with FS, and 11 CV, were assessed in a gait analysis laboratory. Each subject walked repeatedly at self-selected slow, comfortable, and fast walking speeds. The gait analysis provided, for each walk, each subject's stride time, length, and velocity, and ground reaction force, and lower extremity joint kinematics, moments and powers. The data were then anthropometrically scaled and velocity normalized to reduce the influence of subject mass, leg length, and walking speed on the measured gait outcomes. Similarities and differences in the two groups' scaled and normalized gait patterns were then determined. Results show that FS and CV walk with externally similar stride lengths, times, and velocities, and joint angles and ground reaction forces but they use internally different muscle recruitment patterns. Specifically, FS preferentially power gait using their hip flexors instead of their ankle plantarflexors. Interestingly, CV use a similar muscle fatiguing recruitment pattern to walk fast which parallels the common complaint of fatigue reported by FS walking at comfortable speed. # addresses: pierryn@mcmaster.ca (M.R. Pierrynowski), ptiidus@wlu.ca (P.M. Tiidus), galeav@mcmaster.ca (V. Galea). 1
Canadian journal of physiology and pharmacology, Jan 30, 2015
This study examined the effects of a delay in post-ovariectomy replacement of 17β-estradiol (estr... more This study examined the effects of a delay in post-ovariectomy replacement of 17β-estradiol (estrogen) on the post-exercise proliferation of muscle satellite cells. Nine-week-old, ovariectomized, female Sprague-Dawley rats (n = 64) were distributed among 8 groups based on estrogen status (0.25 mg estrogen pellet or sham), exercise status (90 min run at 17 m·min(-1) and a grade of -13.5° or unexercised), and estrogen replacement ("proximal", estrogen replacement within 2 weeks; or "delayed", estrogen replacement at 11 weeks following ovariectomy). Significant increases in satellite cells were found in the soleus and white gastrocnemius muscle (immunofluorescent colocalization of nuclei with Pax7) 72 h following eccentric exercise (p < 0.05) in all exercised groups. Proximal E2 replacement resulted in a further augmentation of muscle satellite cells in exercised rats (p < 0.05) relative to the delayed estrogen replacement group. Expression of PI3K was unalter...
Journal of sports science & medicine, 2004
Massage therapy is commonly used following endurance running races with the expectation that it w... more Massage therapy is commonly used following endurance running races with the expectation that it will enhance post-run recovery of muscle function and reduce soreness. A limited number of studies have reported little or no influence of massage therapy on post-exercise muscle recovery. However, no studies have been conducted in a field setting to assess the potential for massage to influence muscle recovery following an actual endurance running race. To evaluate the potential for repeated massage therapy interventions to influence recovery of quadriceps and hamstring muscle soreness, recovery of quadriceps and hamstring muscle strength and reduction of upper leg muscle swelling over a two week recovery period following an actual road running race. Twelve adult recreational runners (8 male, 4 female) completed a half marathon (21.1 km) road race. On days 1,4, 8, and 11 post-race, subjects received 30 minutes of standardized massage therapy performed by a registered massage therapist on...
Journal of sports science & medicine, 2002
This field study examined the influence of moderate intensity training on gait patterns and work ... more This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS). FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness of mild exercise on work capacity and gait patterns in FS patients. Participants were 14 females (age 47.0 ± 7.6 y) who participated in a 10 wk community based aerobic, strength and stretching program designed for FS individuals. Subjects were evaluated pre- and post-program and at a 2 month follow up. Work capacity was estimated by a sub-maximal PWC 170 cycle ergometer test and a Borg perceived exertion scale. Gait was assessed using OptoTrack three dimensional kinematics with 16 channel analogu...
Journal of sports science & medicine, 2003
The influence of gender on aerobic energy expenditure (EE) during weight training has not been sy... more The influence of gender on aerobic energy expenditure (EE) during weight training has not been systematically researched. We determined the absolute and relative EE during the performance of two weight training programs of different intensities, durations and total work in males and females. Eight male and seven female recreational weight trainers (20-29 y) completed two randomly ordered weight training sessions involving 2 sets of 8 standard upper and lower body lifts at a set cadence separated by 45 seconds rest between sets and lifts (48 hrs apart). Heavy (H) at 100% 8 Repetition Maximum (8RM), 8 reps, ~19 min duration and light (L) at 85% 8RM, 15 reps, ~23 min duration. VO2 was determined continuously throughout the training sessions. Lean body mass (LBM) was estimated from skin fold measures and body weight. Energy expenditure was estimated from breath-by-breath metabolic measurements using portable metabolic assessment equipment (Cosmed K4b(2)). Absolute EE (total kJ) and rate...
Physiotherapy Canada, 2008
To evaluate the effectiveness of muscle rehabilitation modalities, it is first necessary to devel... more To evaluate the effectiveness of muscle rehabilitation modalities, it is first necessary to develop a model to test measures that would assess physiological, sensory, and functional muscle recovery. This study attempted to develop such a model for wrist injury. Healthy male and female adults (n = 25). SUBJECTS performed wrist muscle damage assessment, soreness, discomfort, difficulty, and functional motor task tests before and 1, 2, and 7 days after eccentric wrist muscle contractions. Wrist-related motor task tests, including the perception of discomfort and difficulty during performance, were also conducted. At 24 hours post-eccentric exercises, wrist extension and flexion force declined (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) and soreness (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) and circumference (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05) increased; all returned to normal by 7 days post-exercise. At 24 and 48 hours post-exercise, perception of discomfort and difficulty was elevated during performance of motor tasks (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05). The completion speed of motor tasks was unaffected at any time post-eccentric exercise (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). Loss of wrist muscle force, increased soreness, task discomfort, and difficulty were noted following eccentric exercise. However, subjects appeared able to compensate, such that the speed of completion of motor tasks was not slowed. Longer or more specific motor tasks may be necessary to mimic real work performance decrement and recovery.
Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstétrique et gynécologie du Canada : JOGC, 2003
To design Canadian guidelines advising obstetric care providers of the maternal, fetal, and neona... more To design Canadian guidelines advising obstetric care providers of the maternal, fetal, and neonatal implications of aerobic and strength-conditioning exercises in pregnancy. Knowledge of the impact of exercise on maternal, fetal, and neonatal morbidity, and of the maternal measures of fitness. MEDLINE search from 1966 to 2002 for English-language articles related to studies of maternal aerobic and strength conditioning in a previously sedentary population, maternal aerobic and strength conditioning in a previously active population, impact of aerobic and strength conditioning on early and late pregnancy outcomes, and impact of aerobic and strength conditioning on neonatal outcomes, as well as for review articles and meta-analyses related to exercise in pregnancy. The evidence collected was reviewed by the Society of Obstetricians and Gynaecologists of Canada (SOGC Clinical Practice Obstetrics Committee) with representation from the Canadian Society for Exercise Physiology, and quan...
European Journal of Applied Physiology and Occupational Physiology, 1999
Estrogen has been shown to reduce post-exercise skeletal muscle damage. Exercise-induced muscle d... more Estrogen has been shown to reduce post-exercise skeletal muscle damage. Exercise-induced muscle damage may be a factor in the elevated post-exercise expression of heat-shock proteins (HSPs). Thus, the present investigation was conducted in order to examine the influence of estrogen on post-exercise levels of HSP 72 and heat-shock cognate, HSC 73, in male and female rodents. Prior to an acute bout of treadmill running, male and female Sprague-Dawley rats received daily injections of either 40 microg x kg(-1) of beta-estradiol 3-benzoate or olive oil vehicle for 2 weeks. A two- to fourfold reduction in post-exercise HSP 72 content was observed in the heart, liver, lung and red and white vastus muscles of estradiol-treated males compared with their vehicle-injected counterparts (P < 0.05). Compared to the males, the females had significantly lower post-exercise HSP 72 levels which were not affected by estradiol supplementation. Moreover, estradiol administration in male rodents resulted in a HSP response similar to that of females following exercise. Thus, the results of the present investigation suggest that estrogen is the factor responsible for the observed differences in post-exercise HSP 72 levels between males and females.
Medicine & Science in Sports & Exercise, 2002
Vitamin E supplementation may confer a protective effect against eccentrically biased exercise-in... more Vitamin E supplementation may confer a protective effect against eccentrically biased exercise-induced muscle damage through stabilization of the cell membrane and possibly via inhibition of free radical formation. Evidence supporting a protective role of vitamin E after contraction-induced muscle injury in humans is, however, inconsistent. The present study sought to determine the effect of vitamin E supplementation on indices of exercise-induced muscle damage and the postexercise inflammatory response after performance of repeated eccentric muscle contractions. Young healthy men performed a bout of 240 maximal isokinetic eccentric muscle contractions (0.52 rad.s-1) after being supplemented for 30 d with either vitamin E (N = 9; 1200 IU.d-1) or placebo (N = 7; safflower oil). Measurements of torque (isometric and concentric) decreased (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.05) below preexercise values immediately post- and at 48 h post-exercise. Biopsies taken 24 h postexercise showed a significant increase in the amount of extensive Z-band disruption (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.01); however, neither the torque deficit nor the extent of Z-band disruption were affected by vitamin E. Exercise resulted in increased macrophage cell infiltration (P = 0.05) into muscle, which was also unaffected by vitamin E. Serum CK also increased as a result of the exercise (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.05) with no effect of vitamin E. We conclude that vitamin E supplementation (30 d at 1200 IU.d-1), which resulted in a 2.8-fold higher serum vitamin E concentration (P &amp;amp;amp;amp;amp;amp;amp;lt; 0.01), had no affect on indices of contraction-induced muscle damage nor inflammation (macrophage infiltration) as a result of eccentrically biased muscle contractions.
IUBMB Life, 1996
MyoD is a myogenic transcription factor responsible for skeletal muscle differentiation during de... more MyoD is a myogenic transcription factor responsible for skeletal muscle differentiation during development. Muscle antioxidant enzyme status was determined in transgenic MyoD deactivated mice. While catalase activity was significantly (P<0.05) elevated in soleus and extensor digitorum longus muscles from MyoD deactivated mice, superoxide dismutase and glutathione peroxidase activities were not. While this may imply a greater propensity for inherent oxidative stress, soleus glutathione status was similar between MyoD deactivated mouse and control soleus muscles. Catalase activity is localized primarily in peroxisomes. Therefore elevated catalase activity may also indicate the presence of factors associated with peroxisome proliferation in muscles from MyoD gene-inactivated mice.
Canadian journal of sport sciences = Journal canadien des sciences du sport, 1989
The reported 7-day dietary intake is described for 60 middle-aged and older middle-class adults a... more The reported 7-day dietary intake is described for 60 middle-aged and older middle-class adults aged 45-75 years. The 30 men, who apparently were mostly still moderately active (reported average energy intake for 7-day recording period 11.7 +/- 3.6 MJ/day) showed few deficiencies in the intake of key nutrients relative to standard dietary recommendations. The 30 women were relatively inactive (reported average energy intake 8.1 +/- 1.9 MJ/day). In consequence, some of them had less than an optimal intake of vitamin A, riboflavin and thiamin, while 25 of 60 subjects (17 women, 8 men) had a calcium intake of less than 800 mg/day. Calcium intake was quite closely correlated to total energy intake. Given that a low level of physical activity was apparently responsible for the failure to meet recommended dietary allowances, an increase of habitual physical activity may thus be commended as a simple approach to the optimisation of diet in the sedentary and economically comfortable older a...