A controlled trial of circuit weight training on aerobic capacity and myocardial oxygen demand in men after coronary artery bypass surgery

The effectiveness of vigorous training on cardiorespiratory fitness in persons with spinal cord injury: a systematic review and meta-analysis

DESIGN

Systematic review and meta-analysis.

BACKGROUND AND PURPOSE

Traditional forms of upper-body moderate intensity exercise consistently provide little cardiovascular benefits for persons with spinal cord injury (PwSCI). Explorations of new training methods are vital to improve cardiovascular fitness among PwSCI. This study sought to evaluate the effectiveness of vigorous training on cardiorespiratory fitness in PwSCI.

METHODS

Database search through PubMed, Web of Science, Scopus, SportDiscus, and Cumulative Index of Nursing and Allied Health Literature (CINAHL) was conducted from the databases' inception to November 2020 to identify relevant exercise studies with PwSCI. Two independent reviewers screened articles for inclusion. Data were extracted from included studies and methodological quality evaluated.

RESULTS

Sixteen trials (eight pre-post trials and eight controlled trials [CTs]) with a total of 145 participants were analyzed. Results from pre-post studies revealed significant improvements in cardiorespiratory fitness following high-intensity interval training (HIIT) (Peak Oxygen Uptake [VO_2peak], standardized mean difference [SMD] = 0.81; 95% CI 0.23-1.39; P < 0.01 and Peak Power Output [PPO], SMD = 0.91; 95% CI 0.32-1.5; P < 0.01) and circuit resistance training (CRT) (VO_2peak, MD = 0.38; 95% CI 0.19-0.57; P < 0.01 and PPO, MD = 20.17; 95% CI 8.26-32.08; P < 0.01). Meta-analysis of CTs did not demonstrate significant improvements in cardiorespiratory fitness following vigorous training interventions in comparison to lower intensity training interventions.

CONCLUSION

Evidence from HIIT and CRT interventions suggest benefits for cardiovascular functions; however, vigorous training was not more beneficial than other forms of endurance training. More CTs are needed to better understand the effectiveness of vigorous training on cardiorespiratory fitness in PwSCI.

Interventions to prevent and treat sarcopenia in a surgical population: a systematic review and meta-analysis

BACKGROUND

The aim of this systematic review was to summarize the results of trials evaluating interventions for the reduction of sarcopenia in patients undergoing surgery.

METHODS

Searches were conducted using the Cochrane Central Register of Controlled Trials, MEDLINE and Embase. RCTs evaluating exercise, dietary or pharmacological interventions to address sarcopenia in the perioperative period were included. Treatment effect estimates were expressed as standardized mean differences (MDs) with confidence intervals, and heterogeneity was expressed as I2 values.

RESULTS

Seventy trials including 3402 participants were selected for the data synthesis. Exercise interventions significantly increased muscle mass (MD 0.62, 95 per cent c.i. 0.34 to 0.90; P < 0.001), muscle strength (MD 0.55, 0.39 to 0.71; P < 0.001), measures of gait speed (MD 0.42, 0.05 to 0.79; P = 0.03), and reduced time for completion of set exercises (MD -0.76, -1.12 to -0.40; P < 0.001) compared with controls. Subgroup analysis showed that interventions in the early postoperative period were more likely to have a positive effect on muscle mass (MD 0.71, 0.35 to 1.07; P < 0.001) and timed tests (MD -0.70, -1.10 to -0.30; P = 0.005) than preoperative interventions. Treatment effects on muscle mass (MD 0.09, -0.31 to 0.49; P = 0.66) and strength (MD 0.46, -0.01 to 0.92; P = 0.05) were attenuated by the presence of cancer. Results of analyses restricted to nine trials at low risk of allocation concealment bias and fourteen trials at low risk of attrition bias were comparable to those of the primary analysis. Risk-of-bias assessment showed that most trials were at high risk of incomplete outcome and attrition bias, thus reducing the estimate of certainty of the evidence according to the GRADE assessment tool.

CONCLUSION

Exercise interventions appear beneficial in reducing the impact of sarcopenia. Because of the high risk of bias and low certainty of the current evidence, large RCTs using standardized measures of muscle mass should be undertaken.

Cardiac rehabilitation for patients having cardiac surgery: a systematic review

INTRODUCTION

Cardiac rehabilitation (CR) is recommended for all cardiac patients including patients after cardiac surgery. Since the effect of CR after cardiac surgery has not been well established yet, we conducted a systematic review on the effects of CR for patients after cardiac surgery compared to treatment as usual.

EVIDENCE ACQUISITION

A systematic review of randomized clinical trials (RCTs), quasi-randomized and prospective observational studies in The Cochrane Library, PubMed/MEDLINE and EMBASE was undertaken until October 18th, 2017. Adults after any kind of cardiac surgery were included. Primary outcome was all-cause mortality, other outcomes were serious adverse events, health-related quality of life, work participation, functioning and costs/cost-effectiveness. Risk of bias was evaluated, and the quality of evidence was assessed by the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria.

EVIDENCE SYNTHESIS

Eighteen RCTs and 15 observational studies were included. Low risk of bias was only observed in one observational study. Meta-analysis of RCTs suggested no significant difference of CR compared to control on mortality (random-effects relative risk (RR) 0.93 (95% CI: 0.40-1.81), while observational studies suggested statistically significant beneficial effect associated with CR (random-effects RR=0.49, 95% CI: 0.35 - 0.68). CR did not significantly affect any of the other outcomes. Due to the limited data TSA could not be performed.

CONCLUSIONS

The body of evidence does not allow us to reach any reliable conclusions about the effectiveness of CR following cardiac surgery. Future trials need to be conducted with low risks of bias and clearly defined outcomes.

Comparison of Measures of Maximal and Submaximal Fitness in Response to Exercise

INTRODUCTION

Adoption of physical activity (PA) consistent with current guidelines does not improve maximal cardiorespiratory fitness (mCRF; V˙O2peak) beyond the error of measurement for approximately 30% of adults. Whether PA improves measures of exercise tolerance at submaximal levels (submaximal cardiorespiratory fitness [sCRF]) independent of change in mCRF is unknown. Here we assessed the relationship between exercise-induced changes in mCRF and sCRF.

METHODS

Twenty-five physically inactive men 30-60 yrs old (mean ± SD = 44.3 ± 9.1 yr) completed 4 wk of supervised exercise consisting of 30 min of exercise, five times per week at 65% mCRF. mCRF was assessed using a maximal treadmill test. sCRF was measured as follows: 1) exercise tolerance, the distance traveled during a 12-min time trial on a treadmill, and 2) change in heart rate (HR) at submaximal work rates during the maximal treadmill test. Daily PA was measured by accelerometry at baseline and 4 wk.

RESULTS

mCRF (P = 0.009) and both measures of sCRF (P < 0.001) improved at 4 wk. No change in measures of daily PA was observed at 4-wk compared with baseline (P > 0.05). No association was observed between exercise-induced change in mCRF and change in either measure of sCRF (P > 0.05) after exercise training. In the group of participants who did not improve mCRF beyond the measurement error (n = 13, or 52%), we observed a significant improvement in both measures of sCRF (P < 0.001). Among these 13 individuals, all improved in at least one measure of sCRF.

CONCLUSION

Exercise-induced improvements in mCRF were not associated with improvements in either measure of sCRF. Improvements in submaximal measures of cardiorespiratory fitness are observed in the absence of change in mCRF. Measures of sCRF capture peripheral adaptations to exercise not captured by measures of mCRF alone.

Circuit resistance training is an effective means to enhance muscle strength in older and middle aged adults: A systematic review and meta-analysis

BACKGROUND

Physical exercise, particularly resistance training (RT), is proven treatment to reduce the accelerated decline in muscle strength exhibited by older adults, but its effect is hindered by low adherence rate, even under well-structured programs.

OBJECTIVE AND DATA SOURCES

We investigated the efficacy of circuit resistance training (CRT) on muscle strength, lean mass and aerobic capacity in older adults based on report in MEDLINE, EMBASE, ClinicalTrials.gov and Cochrane electronic (through 8/2016).

STUDY ELIGIBILITY CRITERIA

middle and older aged men and/or women who followed a structured program, assigned to CRT.

STUDY APPRAISAL AND SYNTHESIS METHODS

Out of 237 originally identified articles, 10 articles were included with a total of 362 patients with mean: age -64.5±7.4 years; 3±1.15 sessions/week; session duration 41.8±15.9min.

RESULTS

Upper body strength modestly increased, by 1.14kg (95% CI; 0.28-2.00), whereas larger increment was seen in lower body strength (11.99; 2.92-21.06). Higher program volume (>24 sessions) positively influenced upper body strength and aerobic capacity.

LIMITATIONS

(1) variability in the studies' validity; (2) relatively low number of studies.

CONCLUSION

CRT is a valid alternative to conventional RT. Its shorter duration and lower intensity relative to traditional RT, may increase adherence to training in older adults.

Implementing resistance training in the rehabilitation of coronary heart disease: A systematic review and meta-analysis

BACKGROUND

Resistance training has demonstrated efficacy in cardiac rehabilitation programs, but the optimal prescription of resistance training is unknown. This systematic review with meta-analysis compared the effectiveness of cardiac rehabilitation consisting of resistance training either alone (RT) or in combination with aerobic training (CT) with aerobic training only (AT) on outcomes of physical function. Further, resistance training intensity and intervention duration were examined to identify if these factors moderate efficacy.

METHODS

Six electronic databases were searched to identify studies investigating RT, coronary heart disease and physical function. The overall quality of evidence was assessed using the GRADE approach. Meta-analyses were performed when possible and qualitative analysis was performed for the remaining data.

RESULTS

Improvements in peak oxygen uptake (WMD: 0.61, 95% CI: 0.20-1.10), peak work capacity (SMD: 0.38, 95% CI: 0.11-0.64) and muscular strength (SMD: 0.65, 95% CI: 0.43-0.87) significantly favoured CT over AT with moderate quality evidence. There was no evidence of a difference in effect when comparing RT and AT. Shorter duration CT was superior to shorter duration AT for improving peak oxygen uptake and muscular strength (low quality evidence) while longer duration CT was only superior to longer duration AT in improving muscular strength (moderate quality evidence).

CONCLUSIONS

CT is more beneficial than AT alone for improving physical function. Although preliminary findings are promising, more high-quality evidence is required to determine the efficacy of high intensity resistance training. Shorter duration interventions that include resistance training might allow patients to return to their normal activities of daily living earlier.

Effects of resistance training on muscle strength, exercise capacity, and mobility in middle-aged and elderly patients with coronary artery disease: A meta-analysis

BACKGROUND

Resistance training (RT) is a core component of cardiac rehabilitation. We investigated the effects of RT on exercise capacity, muscle strength, and mobility in middle-aged and elderly patients with coronary artery disease (CAD).

METHODS

We searched for randomized controlled trials of RT versus usual care, or combined RT and aerobic training (AT) versus AT alone, and identified 440 trials in total from inception to January 2014. Participants who had myocardial infarction, coronary revascularization, angina pectoris or CAD were included in the analysis. Those who had heart failure, heart transplants with either cardiac resynchronization therapy or implantable defibrillators were excluded.

RESULTS

Twenty-two trials totaling 1095 participants were analyzed. We performed random-effects meta-analysis. In middle-aged participants, RT increased lower extremity muscle strength [standardized mean difference (SMD): 0.65, 95% confidence interval (CI): 0.35 to 0.95], upper extremity muscle strength (SMD: 0.73, 95% CI: 0.48 to 0.99) and peak oxygen consumption (VO2) [weight mean difference (WMD): 0.92mL/kg/min, 95% CI: 0.12 to 1.72], but did not improve mobility compared with the control. In elderly participants, RT increased lower extremity muscle strength (SMD: 0.63, 95% CI: 0.05 to 1.21), upper extremity muscle strength (SMD: 1.18, 95% CI: 0.56 to 1.80), and peak VO2 (WMD: 0.70mL/kg/min, 95% CI: 0.03 to 1.37), and improved mobility (SMD: 0.61, 95% CI: 0.21 to 1.01) compared with the control.

CONCLUSIONS

Resistance training could increase exercise capacity and muscle strength in middle-aged and elderly patients, and mobility in elderly patients, with CAD.

Resistance exercises for health promotion in coronary patients: evidence of benefits and risks

Aim  This review aims to search and evaluate evidence related to benefits and risks of resistance exercises for patients with coronary artery disease (CAD), post myocardial infarction (MI) and its surgical treatment or coronary artery bypass grafting (CABG). Method  An integrative literature review was carried out. The guiding question of this review was: What evidence is available regarding benefits and risks of muscle resistance training for patients with CAD, post-MI or CABG? Studies from January 1997 to August 2007 were included, taken from the following electronic databases: Medline, PEDro, Cochrane Controlled Trials Database and CINAHL. Results  After the selection process, 11 articles were included in the review. Five articles presented just the resistance exercises, and six combined the resistance exercises with aerobic exercise. The benefits of intervention found in the articles were the improvement of peripheral muscular strength, increase of physical capacity, improvement of emotional state and quality of life. No risks were reported in the articles related to the application of the resistance exercise. Conclusions  The resistance exercises can be used as a safe and effective strategy in health promotion programmes for coronary patients, making social, physical and psychological rehabilitation easier for those people.

Efeitos de 24 semanas de treinamento resistido sobre índices da aptidão aeróbia de mulheres idosas

INTRODUÇÃO E OBJETIVO: O consumo de oxigênio pico (VO2pico) e o limiar anaeróbio (LA) são amplamente aceitos como importantes medidas da aptidão aeróbia. Tradicionalmente, o treinamento aeróbio é visto como o principal meio de se aumentar esses índices. Em contrapartida, o treinamento resistido (TR) não é tipicamente prescrito para este fim. Em indivíduos idosos, tem sido sugerido que o TR é capaz de aprimorar a capacidade aeróbia; entretanto, a temática é controversa. O objetivo do presente estudo foi verificar os efeitos do treinamento resistido sobre índices da capacidade aeróbia de mulheres idosas. METODOLOGIA: Participaram voluntariamente 50 idosas, as quais foram distribuídas em dois possíveis grupos: grupo controle (GC - n = 25; idade média 68,00 ± 6,38) e grupo treinamento (GT - n = 25; idade média 68,04 ± 6,78 anos). Todas as participantes realizaram teste ergoespirométrico em esteira conduzido até a exaustão voluntária antes e após a intervenção. O GT foi submetido a um programa de TR para os principais grupos musculares três vezes por semana durante um período de 24 semanas. Ao GC foi solicitado que mantivessem suas rotinas habituais. Split plot Anova foi utilizada para verificar possíveis diferenças intra e intergrupos. RESULTADOS: Foi observado que o GT apresentou aumento significativo nas variáveis tempo de teste e VO2, tanto no momento do LA como no momento da exaustão. No GC nenhuma das variáveis dependentes sofreu alteração significativa. CONCLUSÃO: Conclui-se que 24 semanas de TR é capaz de promover melhora no desempenho durante teste de esforço cardiopulmonar em uma amostra de mulheres idosas. Futuros estudos serão importantes para elucidar os mecanismos responsáveis por tais adaptações.

Progressive resistance strength training for improving physical function in older adults

BACKGROUND

Muscle weakness in old age is associated with physical function decline. Progressive resistance strength training (PRT) exercises are designed to increase strength.

OBJECTIVES

To assess the effects of PRT on older people and identify adverse events.

SEARCH STRATEGY

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialized Register (to March 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2007, Issue 2), MEDLINE (1966 to May 01, 2008), EMBASE (1980 to February 06 2007), CINAHL (1982 to July 01 2007) and two other electronic databases. We also searched reference lists of articles, reviewed conference abstracts and contacted authors.

SELECTION CRITERIA

Randomised controlled trials reporting physical outcomes of PRT for older people were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed trial quality and extracted data. Data were pooled where appropriate.

MAIN RESULTS

One hundred and twenty one trials with 6700 participants were included. In most trials, PRT was performed two to three times per week and at a high intensity. PRT resulted in a small but significant improvement in physical ability (33 trials, 2172 participants; SMD 0.14, 95% CI 0.05 to 0.22). Functional limitation measures also showed improvements: e.g. there was a modest improvement in gait speed (24 trials, 1179 participants, MD 0.08 m/s, 95% CI 0.04 to 0.12); and a moderate to large effect for getting out of a chair (11 trials, 384 participants, SMD -0.94, 95% CI -1.49 to -0.38). PRT had a large positive effect on muscle strength (73 trials, 3059 participants, SMD 0.84, 95% CI 0.67 to 1.00). Participants with osteoarthritis reported a reduction in pain following PRT(6 trials, 503 participants, SMD -0.30, 95% CI -0.48 to -0.13). There was no evidence from 10 other trials (587 participants) that PRT had an effect on bodily pain. Adverse events were poorly recorded but adverse events related to musculoskeletal complaints, such as joint pain and muscle soreness, were reported in many of the studies that prospectively defined and monitored these events. Serious adverse events were rare, and no serious events were reported to be directly related to the exercise programme.

AUTHORS' CONCLUSIONS

This review provides evidence that PRT is an effective intervention for improving physical functioning in older people, including improving strength and the performance of some simple and complex activities. However, some caution is needed with transferring these exercises for use with clinical populations because adverse events are not adequately reported.

Cardiac rehabilitation outcomes no different after on-pump versus off-pump coronary artery bypass surgery

PURPOSE

Clinical evidence supports lower morbidity with off-pump coronary revascularization surgery as well as superior short- and mid-term outcomes, equivalent graft patency, and reduced cost. The purpose of this study was to compare cardiac rehabilitation (CR) outcomes between patients undergoing on-pump versus off-pump coronary artery bypass surgery.

METHODS

Data were retrospectively examined for patients who participated in CR between 1996 and 2004. Two hundred ninety-five patients who underwent bypass surgery and completed at least 80% of their 36 required sessions were divided into on-pump and off-pump groups. Pre- and post-CR measures included grip strength, flexibility, energy expended during class, quality of life, and self-efficacy.

RESULTS

Both groups were similar with respect to age, sex, ejection fraction, and mean number of grafts. There were no statistical differences between the on-pump and off-pump groups (P > .05) for weight, abdominal and hip circumferences, grip strength, flexibility, and total energy expenditure. In addition, there were no between-group differences regarding quality of life and self-efficacy. Grip strength, flexibility, and energy expenditure during class improved with CR regardless of the surgical procedure (P = .001). Quality of life (P = .001) and self-efficacy (P = .001) also improved.

CONCLUSIONS

The present data support the concept that although there are clinical advantages to off-pump surgery, there is no benefit over on-pump surgery regarding CR. Subsequently, patients undergoing off-pump surgery should be managed similarly as their on-pump counterparts.

Resistance training for chronic heart failure patients on beta blocker medications

BACKGROUND

Resistance training increases the skeletal muscle strength and functional ability of chronic heart failure patients. However, there is limited data regarding the effect of resistance training on the hemodynamic responses and peak oxygen consumption (peak VO(2)) of chronic heart failure patients treated with beta-blocker. This study examined the effect of resistance training on hemodynamics, peak aerobic capacity, muscle strength and quality of life of chronic heart failure patients on beta-blockers medication.

METHODS

Fifteen men diagnosed with chronic heart failure were matched to either a resistance training program or non-training control group. At baseline and after 8 weeks of resistance training patients performed both Balke incremental and maximal strength tests and completed quality of life questionnaires.

RESULTS

The resistance training group demonstrated a significant increase of walking time and peak VO(2) by 11.7% (p=0.002) and approximately 19% (p<0.05), respectively. Peak VO(2) was significantly correlated with both walking time (r=0.54, p=0.038) and change in total weight lifted (r=0.55, p=0.034). Quality of life significantly increased by 87% (p=0.030). The improvement in quality of life was correlated with post training peak VO(2) (r=0.58, p=0.025) and total weight lifted during the post maximal strength test (r=-0.52, p=0.047).

CONCLUSIONS

The benefits from resistance training for chronic heart failure patients on beta-blocker medication included an increased aerobic and exercise capacity, skeletal muscle strength and most importantly, an improvement in the quality of life, which is the main goal of cardiac rehabilitation programs. Furthermore, with appropriate supervision, it is recommended that resistance exercise be added to the exercise rehabilitation program of these patients when possible.

Systematic Review of Progressive Resistance Strength Training in Older Adults

BACKGROUND

The aim of this systematic review was to quantify the effectiveness of progressive resistance strength training (PRT) to reduce physical disability in older people.

METHODS

Randomized controlled trials were identified from searches of relevant databases and study reference lists and contacts with researchers. Two reviewers independently screened the trials for eligibility, rated their quality, and extracted data. Only randomized controlled trials utilizing PRT as the primary intervention in participants, whose group mean age was 60 years or older, were included. Data were pooled using fixed or random effect models to produce weighted mean differences (WMD) and 95% confidence intervals (CI). Standardized mean differences (SMD) were calculated when different units of measurement were used for the outcome of interest.

RESULTS

62 trials (n = 3674) compared PRT with a control group. 14 trials had data available to allow pooling of disability outcomes. Most trials were of poor quality. PRT showed a strong positive effect on strength, although there was significant heterogeneity (41 trials [n = 1955], SMD 0.68; 95% confidence interval [CI] 0.52, 0.84). A modest effect was found on some measures of functional limitations such as gait speed (14 trials [n = 798], WMD 0.07 meters per second; 95% CI 0.04, 0.09). No evidence of an effect was found for physical disability (10 trials [n = 722], SMD 0.01; 95% CI -0.14, 0.16). Adverse events were poorly investigated, but occurred in most studies where they were defined and prospectively monitored.

CONCLUSIONS

PRT results in improvements to muscle strength and some aspects of functional limitation, such as gait speed, in older adults. However, based on current data, the effect of PRT on physical disability remains unclear. Further, due to the poor reporting of adverse events in trials, it is difficult to evaluate the risks associated with PRT.

Effect of a one-year combined exercise training program on body composition in men with coronary artery disease

Increased fat mass, particularly abdominal fat mass, is associated with poor metabolic profiles and an increase in cardiovascular risk factors. The purpose of this study was to evaluate the effect of a 1-year combined aerobic and strength training regimen, compared to aerobic training only, on body composition in patients with coronary artery disease (CAD). Thirty-six males with CAD were assigned to 3 groups: 13 to weight training plus aerobic training (combined training group [CT]), 13 to aerobic training only (aerobic training group [AT]), and 10 to a control group (no exercise [CG]). Body composition was determined by dual-energy x-ray absorptiometry (DEXA). Differences were observed between groups at the end of the study, controlling for prevalues. The total and trunk percent fat mass (%FM) were lower in CT compared with AT and CG (P<.05). The total %FM in AT was significantly (P<.05) lower than in CG, but the %FM of the trunk did not differ between the 2 groups. Fat-free mass (FFM) was significantly higher in CT than in AT and CG (P<.05). The results suggest that a long-term CT program is more effective than an AT program alone in producing changes in body composition. The percentage changes in total and trunk fat mass were higher in CT (-11% and -12%, respectively) than in AT (-2.4% and -0.7%, respectively). Future studies need to investigate the specific health effects of trunkal fat mass loss in patients with CAD.

Effects of exercise and cardiac rehabilitation on cardiovascular outcomes

Cardiac rehabilitation was originally conceived to counteract the deconditioning and comorbidities associated with prolonged bed rest after a myocardial infarction. Contemporary cardiac rehabilitation has taken a more comprehensive approach, with a broader range of participating patients. Relevant cardiovascular outcomes of cardiac rehabilitation can be classified as primary clinical outcomes, intermediate clinical outcomes, and quality-of-life outcomes. In this article, the effects of exercise training alone and, more importantly, the value of comprehensive cardiac rehabilitation are reviewed from the point of view of individual cardiovascular outcomes.

Training and detraining effects of a combined-strength and aerobic exercise program on blood lipids in patients with coronary artery disease

PURPOSE

The aim of this study was to investigate training and detraining effects on blood lipids and apolipoproteins induced by a specific program that combined strength and aerobic exercise in patients with coronary artery disease (CAD).

METHODS

For this study, 14 patients participated in a supervised 8-month training program composed of two strength sessions (60% of 1 repetition maximum) and two aerobic training sessions (60%-85% of maximum heart rate), and 13 patients served as a control group. Blood samples for total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), apolipoproteins A1 (apo-A1) and B (apo-B), and lipoprotein (a) (Lp[a]) were obtained along with muscular strength at the beginning of the study, after 4 and 8 months of training and after 3 months of detraining.

RESULTS

The patients in the intervention group showed favorable alterations after 8 months of training (TC, -9.4; TG, -18.6; HDL-C, 5.2; apo-A1, 11.2%; P <.05), but these were reversed after 3 months of detraining (TC, +3.7; TG, 16.1; HDL-C, -3.6; apo-A1, -5.5%). In addition, body strength also improved after training (27.8%) but reversed (-12.9%) after detraining (P <.05). The patients in the control group did not experience any significant alterations.

CONCLUSIONS

The results indicate that an 8-month training program combining strength and aerobic exercise induces favorable muscular and biochemical adaptations, on TC, TG, HDL-C, and apo-A1 levels, protecting patients with CAD. After 3 months of detraining, however, the favorable adaptations were reversed, underscoring the need of uninterrupted exercise throughout life.

Progressive resistance strength training for physical disability in older people

BACKGROUND

Muscle weakness in old age, is associated with physical disability and an increased risk of falls. Progressive resistance strength (PRT) training exercises (i.e. movements performed against a specific external force that is regularly increased during training) are designed to increase strength in older people.

OBJECTIVES

To assess the effect of PRT on measures of physical disability, functional limitation and impairment in older people, and identify adverse events.

SEARCH STRATEGY

We searched the Cochrane Musculoskeletal Injuries Group specialized register (to August 2002), CENTRAL/CCTR (The Cochrane Library Issue 2, 2002), MEDLINE (1966 to February 1, 2002), EMBASE (1980 to February 1, 2002), CINAHL (1982 to February 1, 2002), Sports Discus (1948 to February 1, 2002), PEDro - The Physiotherapy Evidence Database (accessed February 1, 2002) and Digital Dissertations (accessed February 1, 2002). We also searched reference lists of articles, reviewed conference abstracts and contacted authors.

SELECTION CRITERIA

Randomised trials of PRT alone for older people (i.e. mean age of 60 or over) were included.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Weighted mean differences (WMD) were obtained using fixed or random effect models as appropriate. When measures with different units were pooled, standardised mean differences (SMD) were calculated. Relative risks were calculated for dichotomous outcomes.

MAIN RESULTS

Sixty-six trials with 3783 participants were included. Most studies were small and of poor quality. PRT had a large positive effect on strength (41 trials, 1955 participants), but there was statistical heterogeneity that was not explained by differences in study quality, participant characteristics or the exercise program. Some functional limitation measures showed modest improvements (i.e. gait speed, 14 trials, 798 participants, WMD 0.07 m/s, 95% CI 0.04 to 0.09). However, there was no evidence that PRT had an effect on physical disability when activity measures or health related quality of life measures (HRQOL) were assessed (10 trials, 798 participants, SMD 0.01, 95% CI -0.14 to 0.16 ). Adverse events were poorly recorded, but musculoskeletal injuries were detected in most of the studies that prospectively defined and monitored these events.

REVIEWER'S CONCLUSIONS

PRT appears to be an effective intervention to increase strength in older people and has a positive effect on some functional limitations. However, the effect of this intervention on more substantive outcomes such as measures of disability or HRQOL remains unclear. It is difficult to determine the balance of risks and benefits of PRT because adverse events have generally been poorly collected and recorded.

Hemodynamic responses during aerobic and resistance exercise

PURPOSE

Resistance training has become an accepted part of cardiac rehabilitation programs. Because of the potential for a high afterload to have a negative impact on left ventricular function, there has been concern regarding the safety of resistance training for patients with congestive heart failure.

METHODS

This study addressed this concern by studying 12 healthy volunteers, 12 patients with stable coronary artery disease, and 12 patients with stable congestive heart failure during upright cycling at 90% of ventilatory threshold, and during one set of 10 repeated leg presses, shoulder presses, and biceps curls at 60% to 70% of 1-repetition maximum. Left ventricular function was measured by echocardiography.

RESULTS

The pattern of changes in heart rate, blood pressure, left ventricular ejection fraction, wall thickness, and left ventricular internal diameters was similar across all three groups of subjects, although there were large differences in absolute values. Despite elevations in diastolic and mean arterial pressures during resistance exercise, there was no evidence of significant rest-to-exercise deterioration in left ventricular function during leg press (ejection fraction, 60%-59%, 56%-55%, and 38%-37%), shoulder press (66%-65%, 59%-53%, and 38%-35%), or biceps curls (63%-58%, 53%-54%, and 35%-36%), as compared with cycle ergometry (63%-69%, 51%-57%, and 35%-42%) in the healthy control subjects, the patients with coronary artery disease, and the patients with congestive heart failure, respectively.

CONCLUSIONS

Left ventricular function remains stable during moderate-intensity resistance exercise, even in patients with congestive heart failure, suggesting that this form of exercise therapy can be used safely in rehabilitation programs.

Effects of combined aerobic and resistance training versus aerobic training alone in cardiac rehabilitation

PURPOSE

This study examined the effects of performing combined resistance and aerobic training, versus aerobic training alone, in patients with coronary artery disease.

METHODS

Thirty-six patients with coronary artery disease were randomized to either an aerobic-only training group (AE) or a combined aerobic and resistance training group (AE + R). Both groups performed 30 minutes of aerobic exercise 3 days/week for 6 months. In addition, AE + R group performed two sets of resistance exercise on seven different Nautilus machines after completion of aerobic training each day. Twenty patients (AE: n = 10; AE + R: n = 10) completed the training protocol with > 70% attendance.

RESULTS

Strength gains for AE + R group were greater than for AE group on six of seven resistance machines (P < 0.05). VO2peak increased after training for both AE and AE + R (P < 0.01) with no difference in improvement between the groups. Resting and submaximal exercise heart rates and rate-pressure product were lower after training in the AE + R group (P < 0.01), but not in the AE group. AE + R increased lean mass in arm, trunk, and total body regions (P < 0.01), while AE increased lean mass in trunk region only (P < 0.01). Percent body fat was reduced for AE + R after training (P < 0.05) with a between group trend toward reduced body fat (P = 0.09). Lean mass gain significantly correlated with strength increase in five of seven resistance exercises for AE + R.

CONCLUSIONS

Resistance training adds to the effects of aerobic training in cardiac rehabilitation patients by improving muscular strength, increasing lean body mass, and reducing body fat.

Muscle metabolism assessed by phosphorus-31 nuclear magnetic resonance spectroscopy after myocardial infarction in rehabilitated patients: a 1-year follow-up

BACKGROUND

The most common effect of postmyocardial infarction (post MI) rehabilitation is an increase of peak maximal oxygen consumption correlated with changes in calf muscle metabolism, but there are few data on follow-up after rehabilitation on skeletal muscle and maximal oxygen consumption. The purpose of this study was to investigate the respective modifications in skeletal muscle metabolism and peak oxygen consumption (VO2) occurring during a supervised rehabilitation program and 1 year after MI in patients free of heart failure.

METHODS

Fifteen outpatients were studied prospectively after the acute phase of the MI, at the end of the rehabilitation program (2 months after the MI), and 1 year after. The rehabilitation comprised 20 sessions with three sessions per week. The program consisted of exercise training with bicycle, arm ergometer, and treadmill. The program also included respiratory exercises, psychological support, and counseling for secondary prevention of cardiovascular diseases. At each visit, a stress test on a bicycle ergometer was performed and the peak VO2 was measured. Phosphorus magnetic resonance spectroscopy of the gastrocnemius muscle was performed at rest and during a plantar flexion-type exercise against an adjustable load. Data were analyzed using analysis of variance and post-hoc test when appropriate.

RESULTS

The mechanical power output measured during the bicycle exercise increased from 111 +/- 28 watts at the post MI test to 136 +/- 40 watts after rehabilitation (post rehab) and decreased to 125 +/- 36 watts at 1 year. The peak VO2 increased significantly (P < 0.05) from 22 +/- 7 ml/kg-1/min-1 (post MI) to 27 +/- 9 ml/kg-1/min-1 (post rehab), and decreased significantly to 24 +/- 8 ml/kg-1/min-1 (1 year). The mechanical power output measured in the magnet during the stress test increased from 2.22 +/- 0.13 watts (post MI) to 2.85 +/- 1.24 (post rehab), and stabilized at 2.78 +/- 1.10 watts at 1 year. At the highest workload attained in the three successive tests, the phosphocreatine/(phosphocreatine + inorganic phosphate) ratio rose significantly (P < 0.05) from 0.46 +/- 0.13 (post MI) to 0.51 +/- 0.13 (post rehab) and remained at 0.51 +/- 0.13 at 1 year.

CONCLUSION

The improvement of the peak VO2 after training post MI is not maintained 1 year later. This decline is not accompanied by muscular metabolic abnormalities. This suggests that the muscle metabolism after MI remains normal, and that the long-term decrease of the peak VO2 reflects a global deconditioning that should be avoided by maintaining a long-term phase III rehabilitation program.

Combined high-intensity strength and aerobic training in diverse phase II cardiac rehabilitation patients

BACKGROUND

Developing adequate levels of muscular strength in the cardiac rehabilitation (CR) patient helps return the patient to an active lifestyle. This study evaluated the effects and safety of an 8-week high-intensity strength training (ST) program combined with a traditional aerobic-based CR program on the muscular strength of a diverse phase II CR population.

METHODS

Sixty-one phase II CR patients (age = 60.5 +/- 10.6 years) stratified by risk (high risk: n = 18, ejection fraction = 23.6 +/- 7.8%; intermediate risk: n = 19, ejection fraction = 40.0 +/- 4.6%; low risk: n = 24, ejection fraction = 58.0 +/- 7.7%) and gender (males = 46, females = 15) participated. One repetition maximum (1RM) testing was performed on the horizontal squat, shoulder press, leg extension, lat pulldown, and biceps curl. Patients performed two sets of each exercise 2 days per week at an intensity that started at 60% 1RM and progressed to 80% 1RM by week 4. Weeks 4 to 8 intensity was adjusted individually to maintain 8RM per set. Blood pressure and heart rate/rhythm responses to 1RM testing were monitored in high-risk patients. Muscle soreness and injury were monitored for all patients immediately after 1RM testing and on days 2 and 7.

RESULTS

All patient groups made significant gains (P < 0.05) in muscle strength (mean increase: lower body = 15.3%, upper body = 16.7%). No injury or significant muscle soreness occurred due to 1RM testing. No abnormal heart rate/rhythm or blood pressure responses occurred in high-risk patients.

CONCLUSIONS

Diverse phase II CR patients can improve their strength significantly with a combination of high-intensity strength and aerobic training.

Central and peripheral adaptations after 12 weeks of exercise training in post-coronary artery bypass surgery patients

PURPOSE

Training adaptations in patients with coronary artery disease (CAD) have been reported previously, but little is known about central and peripheral adaptations in those recovering from coronary artery bypass graft surgery (CABG). The purpose of this study was to examine the effects of 12 weeks of endurance exercise training on exercise performance and left ventricular and peripheral vascular reserve in a group of uncomplicated CABG patients.

METHODS

Thirty-one patients were recruited and began training 8 to 10 weeks after uncomplicated CABG. Patients underwent progressive exercise training consisting of walking and jogging, at 75% to 80% maximal oxygen intake (VO2max). Measures of left ventricular function included ejection fraction (EF), ventricular volumes, and the pressure volume ratio, an index of contractility. Peak ischemic exercise calf blood flow and vascular conductance was determined using strain-gauge plethysmography. Maximal oxygen intake and submaximal blood lactate concentration also was determined.

RESULTS

A significant improvement in VO2max (1497 +/- 60 mL/min versus 1691 +/- 71 mL/min) was observed after training. This change was accompanied by an increase in the EF during submaximal exercise (60 +/- 3% versus 63 +/- 2% at 40% VO2max; 61 +/- 3% versus 64 +/- 3% at 70% VO2max) (P < 0.05), and the change in EF from rest to exercise (delta EF). No changes were observed for ventricular volumes during exercise, although there was a trend for a higher stroke volume at 70% VO2max. A significant increase (18%) was observed for peak ischemic exercise calf blood flow and vascular conductance. In addition, submaximal blood lactate concentration was lower after training.

CONCLUSIONS

These data indicate that exercise training for 12 weeks in patients recovering from CABG can elicit significant improvements in functional capacity that, for the most part, are secondary to peripheral adaptations, with limited support for improvement in left ventricular function.

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.

The roles of exercise and fall risk reduction in the prevention of osteoporosis

In summary, the optimal model for the prevention of osteoporotic fractures includes maximization and maintenance of bone strength and minimization of trauma. Numerous determinants of each have been identified, but further work to develop preventative strategies based on these determinants remains to be undertaken. Physical activity is a determinant of peak BMD. There also is evidence that activity during growth modulates the external geometry and trabecular architecture, potentially enhancing skeletal strength, while during the adult years activity may reduce age-related bone loss. The magnitude of the effect of a 7% to 8% increase in peak BMD, if maintained through the adult years, could translate to a 1.5-fold reduction in fracture risk. Moreover, in the older population, appropriate forms of exercise could reduce the risk of falling and, thus, further reduce fracture risk. These data must be considered as preliminary in view of the paucity of long-term fracture outcome data from randomized clinical trials. However, current information suggests that the optimal form of exercise to achieve these objectives may vary through life. Vigorous physical activity (including weight-bearing, resistance, and impact components) during childhood may maximize peak BMD. This type of activity seems optimal through the young adult years, but as inevitable age-related degeneration occurs, activity modification to limit the impact component of exercise may become necessary. In the elderly, progressive strength training has been demonstrated to be a safe and effective form of exercise that reduces risk factors for falling and may also enhance BMD. In the frail elderly, activity to improve balance and confidence also may be valuable. Group activities such as Tai Chi may be cost-effective. Precise prescriptions must await the outcome of well-designed, controlled longitudinal studies that include fracture as an outcome. However, increased physical activity seems to be a sensible component of strategies to reduce osteoporotic fracture.