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N McCartney

Publications and source records attributed to N McCartney.

At least 19 recordsLinked to original sources
PubMed2006

Reduced loading due to spinal-cord injury at birth results in "slender" bones: a case study.

INTRODUCTION: The present case study compared bone density, bone geometry and muscle cross-sectional area (CSA) in a male who sustained spinal-cord injury (SCI) at birth (from here called SCI-B) with two matched controls without SCI, and also with four individuals with SCI of similar level and injury completeness but sustained at age 15 or greater. METHODS: All subjects with SCI were at least 3 years post-injury and had experienced motor incomplete lesions at the cervical level. Computed tomography was used to measure volumetric bone density, indices of bone strength [CSA and maximum, minimum and polar area moments of inertia (I (max), I (min), I (pol))] and muscle CSA at the tibia (66% of tibia length, measured proximally from the distal end). RESULTS: Lower leg muscle CSA of SCI-B was 63+/-6% of values in non-SCI controls, and 72+/-12% of values in other males with SCI. In SCI-B, bone CSA was roughly half (52+/-4%) that of non-SCI controls and 73+/-16% of bone CSA values in other males with SCI. The magnitudes of the area moment of inertia variables (I (max), I (min), and I (pol)) in SCI-B were approximately 25% of control values. Further, the moment of inertia variables in SCI-B were 27-54% of values obtained in other males with SCI, indicating that experiencing SCI in the early stages of life has a remarkable impact on bone shape. Interestingly, tibia bone density did not appear to be affected; the average difference in bone density between SCI-B and non-SCI controls was -1.2+/-0.7%. The bone densities of other males with SCI were 4-19% lower than in SCI-B. CONCLUSIONS: Muscle atrophy and bone loss are commonly reported consequences of SCI. This case reveals that important changes in bone geometry occur after SCI, and that mechanical loading during growth plays a vital role in the development of bone size and shape.

Adult↗
PubMed2005

Long-term body-weight-supported treadmill training and subsequent follow-up in persons with chronic SCI: effects on functional walking ability and measures of subjective well-being.

STUDY DESIGN: Longitudinal, prospective within-subject design. OBJECTIVES: (1) To determine the effects of long-term body-weight-supported treadmill training (BWSTT) on functional walking ability and perceived quality of life in persons with chronic incomplete spinal cord injury (SCI), and (2) to investigate whether training adaptations are maintained following cessation of the BWSTT programme. SETTING: Hamilton, Ontario, Canada. METHODS: A group of 14 individuals with chronic (mean 7.4 years postinjury) incomplete SCI (ASIA B & C) participated in thrice-weekly sessions of BWSTT for a period of approximately 12 months (144 sessions). Functional walking ability and indices of subjective well-being were evaluated during the training programme and over an 8-month follow-up. RESULTS: In total, 13 subjects successfully completed the 144 training sessions in the required study period (max. 15 months). Adherence to the thrice-weekly training frequency was 78.8%. All subjects improved in treadmill walking ability (54% reduction in required external body-weight support (BWS), 180% increase in treadmill walking speed, 335% increase in distance walked/session), and six subjects improved their capacity to walk over ground. There were accompanying increases in satisfaction with life and satisfaction with physical function, both of which were significantly correlated with improvements in treadmill walking ability. All but one subject returned for follow-up assessment 8 months post-training; while there was a slight decline in treadmill walking performance, over ground walking scores remained relatively stable. The only change in subjective well-being in the follow-up was a slight decrease in satisfaction with physical function. CONCLUSION: Thrice-weekly BWSTT for 12 months was an effective stimulus to improve treadmill walking ability and indices of subjective well-being in persons with chronic incomplete SCI, and most of these improvements were maintained for up to 8 months following the cessation of training.

Activities of Daily Living↗
PubMed2005

Body weight supported treadmill training in acute spinal cord injury: impact on muscle and bone.

DESIGN: Longitudinal prospective case series. OBJECTIVE: To evaluate the impact of early introduction post-spinal cord injury (SCI) of twice-weekly body-weight supported treadmill training (BWSTT) on muscle and bone. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Canada. METHODS: Five individuals who had sustained traumatic SCI within 2-6 months participated in the study. Bone mineral densities (BMD) of proximal femur, distal femur, proximal tibia and lumbar spine were measured before and after training, as well as muscle cross-sectional area (CSA), BMD and bone geometry at mid-femur and proximal tibia. Serum osteocalcin and urinary deoxypyridinoline were measured at baseline, and after 24 and 48 sessions of training. RESULTS: All participants experienced increased muscle CSAs, ranging from 3.8 to 56.9%. Reductions in BMD were evident in all participants at almost all lower limb sites after training, ranging in magnitude from -1.2 to -26.7%. Lumbar spine BMD changes ranged from 0.2 to -7.4%. No consistent changes were observed in bone geometry. BWSTT did not alter the expected pattern of change in bone biochemical markers over time. The individual with the greatest improvement in ambulatory ability demonstrated the smallest reduction in lower limb BMD. Conversely, the individual who completed the fewest BWSTT sessions demonstrated the greatest reductions in BMD. CONCLUSIONS: Twice-weekly BWSTT appeared to partially reverse muscle atrophy after SCI, but did not prevent bone loss. Larger, controlled trials should evaluate whether relative preservation of bone loss occurs with regular BWSTT following acute SCI. SPONSORSHIP: Ontario Neurotrauma Foundation.

Adult↗
PubMed2005

The effects of body-weight supported treadmill training on cardiovascular regulation in individuals with motor-complete SCI.

STUDY DESIGN: Four-month longitudinal within-subject exercise training study. OBJECTIVE: Although body-weight supported treadmill training (BWSTT) has not shown promise as a means of improving ambulation in individuals with motor-complete spinal cord injury (SCI), it may still improve cardiovascular health and function in this population. The purpose of this study was to (i) investigate the effects of BWSTT on peripheral muscular and elastic artery dimension and function and measures of heart rate variability (HRV) and blood pressure variability (BPV) in individuals with motor-complete SCI, and (ii) to make a preliminary examination of what factors may predict favourable cardiovascular outcomes following BWSTT in this population. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. METHODS: Six individuals (four male, two female; age 37.7+/-15.4 years) with chronic SCI (C4-T12; ASIA A-B; 7.6+/-9.4 years post-injury) were included in the present investigation. Doppler ultrasound was used to determine femoral (exercising; muscular), carotid (elastic) and brachial (non-exercising control; muscular) artery dimension and function before and after 4 months of BWSTT. Continuous heart rate and blood pressure were also recorded before and after 4-months of BWSTT to determine frequency domain measures of HRV and BPV; clinically valuable indices of neurocardiac and neurovascular control, respectively. RESULTS: Two-way ANOVA (vessel x time) revealed no exercise-induced change in femoral or carotid artery cross-sectional area, blood flow or resistance and no change in carotid artery compliance following the 4 months of BWSTT compared to the non-exercising control brachial artery. However, there was a significant exercise-induced increase in femoral artery compliance. There were no exercise-induced changes in HRV or BPV when all participants were considered together. However, the results suggest that the subgroup of individuals who had a substantial heart rate response to BWSTT (n=3), experienced exercise-training induced changes in HRV reflective of a relative shift toward cardiac vagal predominance and reductions in BPV. CONCLUSIONS: BWSTT may cause an increase in femoral artery compliance in individuals with motor-complete SCI and therefore, should be encouraged as a means of improving cardiovascular health in this population. BWSTT may also cause modest improvements in measures of HRV and BPV in a select subgroup of individuals who respond to ambulation with moderate to large increases in HR. In the present study, factors associated with a substantial HR response to BWSTT were a propensity to orthostatic intolerance and muscular spasticity.

Adult↗
PubMed2003

Efficacy of home-based exercise for improving quality of life among elderly women with symptomatic osteoporosis-related vertebral fractures.

This randomized controlled trial was designed to investigate the effect of a 6-month home-based exercise program versus control (usual activities) on quality of life for postmenopausal women with osteoporosis who had at least one vertebral fracture. Twelve-month assessments of outcomes were completed to determine if women would continue exercising with minimal supervision and if benefit could be sustained. The home exercise program followed a "lifestyle exercise" approach where participants completed exercises 60 min per day, 3 days a week and could complete exercises in small periods of time throughout the day. Exercise activities included stretching, strength training and aerobics (i.e. walking). Participants were assessed at baseline, 6 months, and 12 months using the Osteoporosis Quality of Life Questionnaire (OQLQ), the Sickness Impact Profile (SIP), a balance test, and the Timed Up And Go test. Bone mineral density was assessed at baseline and 12 months for both the lumbar spine and femoral neck. Quality of life (OQLQ) improved over 6 months in the exercise group compared to the control group in the domains of symptoms (P=0.003), emotion (P=0.01) and leisure (P=0.03). Results from the balance test indicated a greater effect in the exercise group over 12 months (P<0.05). There were no significant differences between groups in measures of Timed Up and Go, SIP at 6 and 12 months, and femoral neck and lumbar spine bone mineral density at 12 months. Home-based exercise with minimal supervision improves quality of life in elderly women with vertebral fractures. Future research is needed to determine if home exercise programs reduce falls and fall-related injuries in the elderly.

Aged↗
PubMed2003

Long-term exercise training in persons with spinal cord injury: effects on strength, arm ergometry performance and psychological well-being.

STUDY DESIGN: Randomized controlled trial of exercise training in persons with spinal cord injury. OBJECTIVE: The purpose of this study was to examine the effects of 9 months of twice-weekly exercise training on strength, arm ergometry performance, and indices of psychological well-being and quality of life. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. METHODS: Thirty-four men and women (aged 19-65 years) with traumatic spinal cord injury (C4-L1; ASIA A-D) of 1-24 years duration volunteered to participate, and were randomized into exercise (EX; n=21) and control (CON; n=13) groups. Twenty-three subjects (11 EX; 12 CON) successfully completed the 9-month study. Subjects were assessed for one repetition maximum (1RM) strength, arm ergometry performance, and several indices of quality of life and psychological well-being at baseline, 3, 6, and 9 months. RESULTS: At baseline, there were no significant differences between groups in age, submaximal arm ergometry performance, muscle strength, or psychological well-being. Following training, the EX group had significant increases in submaximal arm ergometry power output (81%; P<0.05), and significant increases in upper body muscle strength (19-34%; P<0.05); no significant changes occurred in CON. Participants in EX reported significantly less pain, stress and depression after training, and scored higher than CON in indices of satisfaction with physical function, level of perceived health and overall quality of life (P<0.05). Exercise adherence (per cent of prescribed sessions attended) in those subjects who completed the 9 months of training was 82.5%. CONCLUSIONS: These results demonstrate that long-term twice-weekly exercise training in this population is feasible, and results in significant gains in both physical and psychological well-being.

Adult↗
PubMed2003

Maintenance of exercise participation in individuals with spinal cord injury: effects on quality of life, stress and pain.

STUDY DESIGN: Follow-up study of seven individuals with spinal cord injury (SCI) who completed a 9-month randomized control trial (RCT) of exercise training. OBJECTIVE: In a 9-month RCT conducted in our lab, individuals with SCI who participated in a twice-weekly supervised exercise training reported greater perceived quality of life (PQOL), and less stress and pain than a nonexercising control cohort. The present follow-up study examined the voluntary continuation of exercise training after the study ended and the persistence of the accrued psychosocial benefits. SETTING: Centre for Health Promotion and Rehabilitation, McMaster University, Hamilton, Ontario, Canada. METHODS: Five men and two women (age 42.3+/-3.6 years) with SCI (C5-T12; ASIA A-D 12.7+/-8.2 years postinjury) were invited to continue supervised exercise training twice weekly at the completion of the 9-month RCT. Exercise adherence, PQOL, stress and bodily pain were measured at a 3-month follow-up and were compared to values obtained at baseline, and at 3, 6 and 9 months during the intervention. RESULTS: There was a significant decrease in adherence at the 3-month follow-up compared to the overall 9-month adherence rate (42.7 versus 80.6%, respectively; P<0.01). There was also a significant decrease in PQOL (P<0.05) and a trend for increased pain (P=0.07) and stress (P=0.12), at follow-up compared to the end of the 9-month trial. Finally, there was a significant negative correlation between pain at the conclusion of the RCT and exercise adherence over the 3-month follow-up period (r=-0.91; P<0.01). CONCLUSIONS: These findings emphasize the importance of continued exercise adherence to the maintenance of exercise-related increases in psychological well-being among individuals with SCI.

Adult↗
PubMed2001

Acute cardiovascular responses to leg-press resistance exercise in heart transplant recipients.

BACKGROUND: Reduced skeletal muscle strength is characteristic of individuals following heart transplantation. Weight lifting exercise has been demonstrated as an effective means by which to increase muscular strength in other cardiac patients but the appropriateness of this form of exercise in heart transplant patients has not been investigated. The purpose of this study was to describe the cardiovascular responses of heart transplant patients to a single, prolonged bout of weight lifting training. METHODS: Twenty-three heart transplant recipients were stratified into early (Early; 3 months; n=6), intermediate (Intermediate; 1-3 years; n=7) and late (Late; 5-14 years; n=10) post transplant groups and studied in four experimental conditions: supine rest, upright rest, single leg-press exercise (28 repetitions over 2 min 20 s at 50% 1 repetition maximum) and recovery. Swan-Ganz catheterization allowed measurement of right heart pressures and cardiac output by thermodilution. Systemic arterial pressures and heart rate were measured continuously using a non-invasive finger cuff. RESULTS: Cardiac output increased by 30, 40 and 54% during exercise in Early, Intermediate and Late, respectively. Heart rate increased by 4.5% in Early compared to 11 and 16% increases in Intermediate and Late. At peak exercise, systolic blood pressures reached average values of 179+/-9, 180+/-14 and 176+/-8 mmHg in Early, Intermediate and Late, respectively. Average mean pulmonary artery pressure did not exceed 30 mmHg and average pulmonary wedge pressure did not exceed 15 mmHg in any group during the exercise. CONCLUSIONS: These observations indicate that a lengthened set of single leg-press exercise at a moderate lifting intensity can be performed within safe and acceptable physiological limits in patients following heart transplantation. To better address the specific rehabilitation needs of heart transplant recipients, future research should focus on developing training programs which include weight lifting exercise.

Adult↗
PubMed2000

Functional capacity in patients with congestive heart failure.

BACKGROUND: Six-minute walk distance (6MWd) is related to activities of daily living and is also an independent predictor of prognosis in patients with congestive heart failure (CHF). Therefore, it is important to determine factors that contribute to the variability of this test. METHODS AND RESULTS: We assessed the relationship between 6MWd and peak aerobic capacity (VO2) and dynamic muscle strength in 180 patients with CHF (age, 66+/-10 years; 146 men, 34 women; ejection fraction, .29+/-0.08). We also hypothesized that a measure of work performed during the walk test (6MWw) would be a better indicator of exercise capacity than 6MWd. The 6MWd had weak to moderate correlations with dynamic muscle strength (r = 0.33 to 0.41) and peak VO2 (r = 0.48). However, 6MWw was strongly related to dynamic muscle strength (r = 0.63 to 0.70) and peak VO2 (r = 0.77). Multivariate analysis indicated that a model combining dynamic muscle strength and peak VO2 explained 69% of the variance in 6MWw, more than with peak VO2 alone (R2 = 0.59). CONCLUSIONS: Compared with 6MWd, 6MWw correlates significantly better with peak VO2 and dynamic muscle strength, suggesting that 6MWw may be a better reflection of a patient's exercise capacity. Furthermore, these results suggest that an exercise program combining both aerobic and strength training in patients with CHF may improve 6MWw and therefore 6MWd.

Aged↗
PubMed1999

Hypotension following mild bouts of resistance exercise and submaximal dynamic exercise.

Our purposes were (1) to examine resting arterial blood pressure following an acute bout of resistance exercise and submaximal dynamic exercise, (2) to examine the effects of these exercises on the plasma concentrations of atrial natriuretic peptide ([ANP]), and (3) to evaluate the potential relationship between [ANP] and post-exercise blood pressure. Thirteen males [24.3+/-(2.4) years] performed 15 min of unilateral leg press exercise (65% of their one-repetition maximum) and, I week later, approximately 15 min of cycle ergometry (at 65% of their maximum oxygen consumption). Intra-arterial pressure was monitored during exercise and for 1 h post-exercise. Arterial blood was drawn at rest, during exercise and at intervals up to 60 min post-exercise for analysis of haematocrit and [alphaANP]. No differences occurred in blood pressure between trials, but significant decrements occurred following exercise in both trials. Systolic pressure was approximately 20 mmHg lower than before exercise after 10 min, and mean pressure was approximately 7 mmHg lower from 30 min onwards. Only slight (non-significant) elevations in [alphaANP] were detected immediately following exercise, with the concentrations declining to pre-exercise values by 5 min post-exercise. We conclude that post-exercise hypotension occurs following acute bouts of either resistance or submaximal dynamic exercise and, in this investigation, that this decreased blood pressure was not directly related to the release of alphaANP.

Adult↗
PubMed1999

Acute responses to resistance training and safety.

Resistance training is widely used in fitness programs for healthy individuals of all ages and has become accepted as part of the exercise rehabilitation process for patients with coronary artery disease. It is only during the past decade that the acute circulatory responses to resistance exercise have been investigated directly, using intra-arterial measurement techniques and two-dimensional echocardiography. This review examines the factors that influence the acute circulatory responses to resistance training. These include the number of repetitions, the absolute and relative load, the muscle mass engaged in the lifting, the joint angle, and the Valsalva maneuver. There is discussion of the responses in patients with coronary artery disease and the effects of resistance training on the acute responses. The review ends with a discussion of the safety of this form of exercise and concludes that it is safe and appropriate for most healthy individuals and many of those with different diseases.

Biomechanical Phenomena↗
PubMed1999

Muscle substrate utilization and lactate production.

Biopsies (biceps) were examined in 8 bodybuilders across a typical arm-curl training session (80% 1-RM). [PCr] and [glycogen] decreased 62 and 12% after 1 set (n = 4), and 50 and 24% after 3 sets (n = 4). [Lactate] was 91 and 118 mmol &times kg-1, respectively, after 1 and 3 sets. Fatigue was probably partially caused by decreased [PCr] and increased [H+] (first set) and by decreased [H+] in subsequent sets.

Adenosine Triphosphate↗
PubMed1998

Role of resistance training in heart disease.

Since the mid-1980s resistance training has become an accepted part of the exercise rehabilitation process for patients eligible for traditional cardiac rehabilitation programs. A growing number of studies have demonstrated the safety of resistance training in Phase III/IV programs (Phase III--community based, beginning 6-12 wk posthospital discharge; a typical patient would be clinically stable with a functional capacity of > or = 5 METs; Phase IV--long-term maintenance) and more recently in Phase II (beginning within 3 wk posthospital discharge and lasting up to 3 months). Evidence is consistent that this form of training provokes fewer signs and symptoms of myocardial ischemia than aerobic testing and training, perhaps because of a lower heart rate (HR) and higher diastolic pressure combining to produce improved coronary artery filling. The major role of resistance training in heart disease patients is to promote increased dynamic muscle strength. Increases in muscular strength have been associated with increased peak exercise performance, improved submaximal endurance, and reduced ratings of perceived leg effort. Two studies show that resistance training may result in improved self-efficacy for strength and exercise tasks and improved quality of life parameters such as total mood disturbance, depression/dejection, fatigue/inertia, and emotional health domain scores. The data on risk factor modification are somewhat equivocal. Studies on blood lipid profiles have mostly been contaminated by confounders, and the effects on blood pressure (BP) are inconsistent. There are encouraging reports that resistance training may increase glucose tolerance and insulin sensitivity, independent of changes in body fat or aerobic capacity. Future studies are needed in patients with congestive heart failure and orthotopic heart transplantation; muscle weakness is common in these groups and makes them excellent candidates to benefit from this form of exercise.

Blood Pressure↗
PubMed1996

A longitudinal trial of weight training in the elderly: continued improvements in year 2.

We conducted a 2-year (42 weeks of consecutive training in each year, separated by 10 weeks of testing and vacation time) randomized, controlled trial of weight training in 142 healthy male and female subjects, aged 60 to 80 years. Measurements included dynamic strength, symptom-limited endurance in cycling, treadmill walking and stair climbing, muscle size, and bone mineral density and content of the lumbar spine and whole body. One hundred and thirteen subjects completed the study (57 exercise, 56 control), with a mean attendance of 85% among the exercisers. Muscle strength was unchanged in the control subjects but increased (collapsed across age and gender) from 32% (leg press) to 90% (military press) in the exercisers. Symptom-limited endurance in cycling, treadmill walking, and stair climbing increased in the exercisers by (mean +/- SE) 6.2 +/- 0.8%, 29.2 +/- 7.3%, and 57 +/- 12%, respectively; the only change in the controls was an unanticipated 33% increase in stair climbing performance during the first year. These values were unchanged in the controls. Cross-sectional area of the knee extensors increased by 8.7 +/- 0.9% in the trained subjects and was unchanged in controls. Measures of whole body, lumbar spine bone mineral density, and lumbar spine bone mineral content were unchanged in the exercisers, but whole body bone mineral content decreased by 1%. In contrast, there were small increases (< 4.0%) in bone mineral density among the controls. Long-term weight training proved to be a safe and well-tolerated mode of exercise for the elderly. Increased strength was associated with muscle hypertrophy in each year, and with increased endurance in cycling, walking, and stair climbing. There were no changes in bone mineral density but a small reduction in whole body bone mineral content.

Aged↗
PubMed1996

Circulatory responses to weight lifting, walking, and stair climbing in older males.

OBJECTIVES: To compare the heart rate and intra-arterial blood pressure responses during weight lifting, horizontal and uphill walking, and stair climbing in older male subjects. DESIGN: We used intra-brachial artery catheterization to compare the arterial blood pressure (ABP) and heart rate (HR) responses during 10 repetitions (approximately 40 s) of single-arm curl (SAC) and single-arm overhead military press (SAMP) (70% of the one repetition maximum-1RM); 12 repetitions (approximately 50 s) of single- (SLP) and double-leg press (DLP) weight-lifting exercises (80% of 1RM); 10 minutes of horizontal treadmill walking (T10) at 2.5 mph holding a 20-pound weight in minutes 4 to 6 (T10) and 30 pounds in minutes 8 to 10 (T10); 4 minutes of treadmill walking (T4) at 3.0 mph up an 8% incline; and 12 flights (192 steps) of stair climbing (STR) at 60 to 65 steps/minute on a Stiarmaster 6000 ergometer (approximately 3 minutes). SETTING: McMaster University, Hamilton, Ontario, Canada. PARTICIPANTS: Seventeen healthy males aged (mean +/- SE) 64.4 +/- 0.6 years. MEASUREMENTS: Continuous intra-arterial measurements of systolic, diastolic, and mean arterial pressure and heart rate and rate-pressure product. RESULTS: The peak values of HR, ABP and rate-pressure product (HR.BPs/1000;(RPP,10(3))) were not systematically ordered among the various activities. The lowest peak values for all variables were recorded during the initial 4 minutes of horizontal treadmill walking. The STR and T4 walking exercises elicited higher HRs (151 +/- 3.2 and 121 +/- 3.4 bpm) than the weight lifting (range from 100 +/- 4.8 (SAC) to 113 +/- 3.8 bpm (SAMP)), but the converse was true for diastolic pressure (range from 128 +/- 6.3 (SAC) to 151 +/- 4.8 mm Hg (SAMP) versus 101 +/- 2.5 (T4) to 118 +/- 3.4 mm Hg (T10) and mean arterial pressure (range from 145 +/- 4.5 (SAC) to 158 +/- 4.8 mm Hg (SAMP) versus 129 +/- 3.4 in T4 to 148 +/- 3.8 (T10) and 157 +/- 4.1 mm Hg (STR)). The peak systolic pressure was greatest in STR (271 +/- 9.6 mm Hg) followed by SAMP (261 +/- 9.3 mmHg) and T10 (244 +/- 6.4 mm Hg) and was lowest in SAC (224 +/- 10.5 mm Hg) and T10 (220 +/- 5.7 mm Hg). The peak RPP descended in sequence from STR (41 +/- 1.8), SAMP (29.8 +/- 1.7), T4 (28.1 +/- 1.3), DLP (27.2 +/- 1.3), T10 (27.1 +/- 1.4), SLP (25.4 +/- 1.7), T10 (22.7 +/- 1.2) and SAC (22.0 +/- 2.2). CONCLUSION: We concluded that older adults who engage in weight lifting with heavy submaximal loads are exposed to no more peak circulatory stress than that created during a few minutes of inclined walking. Moreover, climbing only three to four flights of stairs at a moderate pace (approximately 50-70 s) elicits peak circulatory demands similar to, but at a much more rapid rate of adjustment than, 10 minutes of horizontal walking at 2.5 mph intermittently carrying a 30-pound weight or 4 minutes of walking up a moderately steep slope.

Activities of Daily Living↗
PubMed1996

Gender differences in isometric contractile properties and fatigability in elderly human muscle.

This study had two purposes: to compare the isometric contractile characteristics and fatigability in the elbow flexors (EF) and ankle dorsiflexors (DF) in older males and females (60-80 years), and to determine the effects of almost 2 years of twice weekly dynamic weight-lifting training on these properties One hundred nine male and female subjects completed the 22-month intervention, 54 in the exercise group and 55 in the control group. Isometric contractile properties and fatigue characteristics were assessed at baseline, 10 months, and 22 months. At baseline, males were significantly stronger (p < .05) than females in evoked twitch torque (Pt) and maximal voluntary strength (MVC) in both EF and DF. Females exhibited significantly less fatigue (expressed either absolutely or relatively) than males in both Pt and MVC during a 3-min protocol of intermittent MVCs (5 s contraction; 2 s rest). There were no significant effects of the 22 months of dynamic training on either the isometric contractile properties or the fatigue characteristics, suggesting a very strong and persistent specificity of training effect.

Aged↗
PubMed1996

The role of resistance training in patients with cardiac disease.

During the past decade, research has demonstrated that resistance training is a safe and effective mode of exercise for cardiac patients who are suitable candidates for conventional exercise rehabilitation. Fears of an excessive pressor response seem unwarranted and the incidence of ischaemia is less than that during dynamic exercise such as walking and cycling. Major benefits from resistance training include improved muscular strength, increased peak exercise capacity and submaximal endurance, reduced ratings of perceived exertion during exercise and improved self-efficacy in strength-related tasks. The effects of resistance training on blood pressure and blood lipids levels are equivocal, but there may be positive effects on glucose metabolism. This form of training is likely to assume greater importance in cardiac rehabilitation in the future.

Coronary Disease↗