Matthew S. Feigenbaum

Prescription of resistance training for health and disease

When prescribed appropriately, resistance training is effective for developing fitness, health, and for the prevention and rehabilitation of orthopedic injuries. Because resistance training is an integral component in the comprehensive health program promoted by the major health organizations (e.g., American College of Sports Medicine, American Heart Association, American Association of Cardiovascular and Cardiopulmonary Rehabilitation, Surgeon Generals Office), population-specific guidelines have recently been published. The current research indicates that, for healthy persons of all ages and many patients with chronic diseases, single set programs of up to 15 repetitions performed a minimum of 2 d x wk(-1) are recommended. Each workout session should consist of 8-10 different exercises that train the major muscle groups. Single set programs are less time consuming and more cost efficient, which generally translates into improved program compliance. Further, single set programs are recommended for the above-mentioned populations because they produce most of the health and fitness benefits of multiple set programs. The goal of this type of program is to develop and maintain a significant amount of muscle mass, endurance, and strength to contribute to overall fitness and health. Patients with chronic diseases (e.g., arthritis) may have to limit range of motion for some exercises and use lighter weights with more repetitions.

Neuroendocrine Activation in Heart Failure Is Modified by Endurance Exercise Training

Abstract OBJECTIVES The purpose of this study was to determine whether endurance exercise training could buffer neuroendocrine activity in chronic heart failure patients. BACKGROUND Neuroendocrine activation is associated with poor long-term prognosis in heart failure. There is growing consensus that exercise may be beneficial by altering the clinical course of heart failure, but the mechanisms responsible for exercise-induced benefits are unclear. METHODS Nineteen heart failure patients (ischemic disease; New York Heart Association [NYHA] class II or III) were randomly assigned to either a training group or to a control group. Exercise training consisted of supervised walking three times a week for 16 weeks at 40% to 70% of peak oxygen uptake. Medications were unchanged. Neurohormones were measured at study entry and after 16 weeks. RESULTS The training group (n = 10; age = 61 ± 6 years; EF = 30 ± 6%) and control group (n = 9; age = 62 ± 7 years; EF = 29 ± 7%) did not differ in clinical findings at study entry. Resting levels of angiotensin II, aldosterone, vasopressin and atrial natriuretic peptide in the training and control groups did not differ at study entry (5.6 ± 1.3 pg/ml; 158 ± 38 pg/ml; 6.1 ± 2.0 pg/ml; 37 ± 8 pg/ml training group vs. 4.8 ± 1.2; 146 ± 23; 4.9 ± 1.1; 35 ± 10 control group). Peak exercise levels of angiotensin II, aldosterone, vasopressin and atrial natriuretic peptide in the exercise and control groups did not differ at study entry. After 16 weeks, rest and peak exercise hormone levels were unchanged in control patients. Peak exercise neurohormone levels were unchanged in the training group, but resting levels were significantly (p CONCLUSIONS Our data indicate that 16 weeks of endurance exercise training modified resting neuroendocrine hyperactivity in heart failure patients. Reduction in circulating neurohormones may have a beneficial impact on long-term prognosis.

Prescription of resistance training for healthy populations

AbstractAlthough there are well documented protective health benefits conferred by regular physical activity, most individuals of all ages are not physically active at a level for sufficient maintenance of health. Consequently, a major public health goal is to improve the collective health and fitness levels of all individuals. The American College of Sports Medicine (ACSM) and other international organisations have established guidelines for comprehensive exercise programmes composed of aerobic, flexibility and resistance-exercise training. Resistance training is the most effective method available for maintaining and increasing lean body mass and improving muscular strength and endurance.Furthermore, there is an increasing amount of evidence suggesting that resistance training may significantly improve many health factors associated with the prevention of chronic diseases. These health benefits can be safely obtained by most segments of the population when prescribed appropriate resistance-exercise programmes. Resistance-training programmes should be tailored to meet the needs and goals of the individual and should incorporate a variety of exercises performed at a sufficient intensity to enhance the development and maintenance of muscular strength and endurance, and lean body mass. A minimum of 1 set of 8 to 10 exercises (multi-joint and single joint) that involve the major muscle groups should be performed 2 to 3 times a week for healthy participants of all ages. More technical and advanced training including periodised multiple set regimens and/or advanced exercises may be more appropriate for individuals whose goals include maximum gains in strength and lean body mass. However, the existing literature supports the guidelines as outlined in this paper for children and adults of all ages seeking the health and fitness benefits associated with resistance training.

Effect of resistance training volume on strength and muscle thickness

The purpose of this study was to determine the effects of different volumes of high-intensity resistance training on isometric torque and muscle thickness. Training was conducted three times per week using one set (low volume, EX-1, N = 18) or three sets (high volume, EX-3, N = 20) of dynamic variable resistance exercise. Ten subjects acted as nontraining controls (CONT). Bilateral knee extension (KEXT) and flexion (KFLEX) exercise was performed to fatigue within 8-12 repetitions for 14 wk. Maximal isometric KEXT and KFLEX torque was tested at 6 degrees, 24 degrees, 42 degrees, 60 degrees, 78 degrees, 96 degrees, and 108 degrees of KFLEX using a MedX (Ocala, FL) KEXT/KFLEX ergometer. The anterior (ANT), lateral (LAT), and posterior (POST) right thigh, the medialis muscle (MED), and the lateralis muscle (LATER) were assessed for thickness by B-mode ultrasound (ULTRA). Both training groups improved torque output at most angles, but there was no difference between EX-1 and EX-3 (P > or = 0.05). ULTRA detected increases in muscle thickness for EX-1 at 60% LAT and 40% and 60% POST. EX-3 increased muscle thickness at the MED, and 40% and 60% POST. In conclusion, one set of high intensity resistance training was as effective as three sets for increasing KEXT and KFLEX isometric torque and muscle thickness in previously untrained adults.

Strength Training: Rationale for Current Guidelines for Adult Fitness Programs

Strength training is an effective method for developing musculoskeletal strength and is often prescribed for fitness, health, and the prevention and rehabilitation of orthopedic injuries. Because strength training is an integral component in the comprehensive health program promoted by the major health organizations (eg, American College of Sports Medicine, American Heart Association, Centers for Disease Control and Prevention, US Surgeon Generals Office), population-specific guidelines have recently been published. For the average adult beginning a strength training program, current research indicates that single-set programs performed a minimum of two times per week are recommended over multiple-set programs because they are less time-consuming, more cost-efficient, and produce most of the health and fitness benefits. The goal of this type of program is to develop and maintain a significant amount of muscle mass, endurance, and strength to contribute to overall fitness and health, not to optimize strength, power, and hypertrophy. By incorporating exercise prescription into patient counseling, clinicians can further increase their effectiveness as prevention-oriented healthcare providers.

Contracted plasma and blood volume in chronic heart failure

OBJECTIVES The purpose of this study was to determine if long-term pharmacotherapy mediated changes in intravascular plasma and blood volumes in patients with chronic heart failure (CHF). BACKGROUND Intravascular fluid volume expansion is an acute compensatory adaptation to ventricular dysfunction in patients with CHF. To our knowledge there are no reports on plasma and blood volume measures in clinically stable patients with CHF receiving standard pharmacotherapy. Such information may provide a better understanding of the clinical hallmarks of heart failure. METHODS Plasma volume (PV) and blood volume (BV) were measured in 12 patients (62.8 +/- 8.2 years old, 175.2 +/- 6.8 cm, 96.2 +/- 18.2 kg, peak oxygen consumption (VO2max) 15.2 +/- 3.3 ml/kg per min) with CHF secondary to coronary artery disease (left ventricular ejection fraction 31.2 +/- 9.7, New York Heart Association functional class 2.5 +/- 0.5) and seven healthy subjects (71.7 +/- 5.3 years old, 177.1 +/- 10.8 cm, 84.4 +/- 11.7 kg, VO2max 26.0 +/- 6.5 ml/kg per min) 3 to 4 h after eating and after supine rest using the Evans blue dye dilution technique. Venous blood samples were collected before blue dye infusion and analyzed for hematocrit (corrected 4% for trapped plasma and venous to whole body hematocrit ratio) and hemoglobin. RESULTS Hematocrit was 36.6 +/- 3.5% and 37.4 +/- 1.1%, and hemoglobin was 15.4 +/- 1.9 and 16.2 +/- 1.4 g/dl for patients with CHF and control subjects, respectively. Absolute PV was 3489.3 +/- 655.0 and 3728.7 +/- 813.2 ml, and absolute BV was 5,496.8 +/- 1,025.4 and 5,942.4 +/- 1,182.2 ml in patients with CHF and control subjects, respectively. Relative PV was 34.1 +/- 12.9 versus 44.5 +/- 9.0 ml/kg (p < or = 0.05), and relative BV was 58.5 +/- 12.3 versus 70.8 +/- 12.6 ml/kg (p < or = 0.05) in patients with CHF and control subjects, respectively. CONCLUSIONS Our data indicate significantly lower intravascular volumes in patients with CHF than in control subjects, indicating a deconditioned state or excessive diuresis, or both. The contracted PV and BV may contribute to exercise intolerance, shortness of breath and chronic fatigue, secondary to reduced cardiac output or regional blood flow, or both.

Exercise Prescription for Physical Fitness.

In this paper, the current guidelines on exercise for physical fitness are examined, and important issues that may influence the updating of the ACSM exercise statement are identified. The current ACSM position stand (1990) on exercise for fitness has been criticized for failing to emphasize that health benefits may result from participation in lower intensity/volume physical activities. The primary difference between exercise prescription for fitness and physical activity for health is that fitness-oriented programs encompass health benefits, whereas guidelines designed specifically to elicit health benefits often do not incorporate the intensity or volume of training necessary to bring about improved fitness. Research is needed to provide more precise recommendations concerning the progression of training and how much should be included in warm-up and cool-down periods. Current and future guidelines will continue to emphasize factors that result in permanent lifestyle change and encourage a lifetime of ...

Assessing dietary fat intake in chronic disease rehabilitation programs.

PURPOSE Previous work has established that the Heart Fit Rx Diet Habits Survey (HFD), formerly the Food Frequency Assessment Tool, compares favorably (r = 0.78; P <.01) with the Oregon Health Sciences University Diet Habit Survey. The purpose of this study was to assess the validity and reliability of the HFD in estimating fat intake as a percentage of calories. METHODS The validity study assessed 137 patients undergoing cardiac rehabilitation (age, 60.7 +/- 11.3 years) who completed the HFD (29 questions, 11 of which were dietary fat related [fat subscore]) and a 3-day food record. A regression equation was obtained using HFD subscores to estimate fat intake as a percentage of calories. The regression equation was tested using 50 patients not included in the original cohort. Reliability was assessed using a third group of 31 patients in a 4-week test-retest analysis. RESULTS The correlation coefficient between the 3-day record and the HFD fat subscore was 0.65 (P <.01). The correlation coefficient for women (r = 0.77) was slightly higher than for men (r = 0.62). The regression equation derived from the HFD fat subscore was as follows: percentage of dietary fat = 50.65 - 0.736 (HFD fat subscore). The correlation coefficient for actual and predicted values was 0.58 (P <.01). Differences between estimated fat intake, as determined by the 3-day record and the HFD, ranged from 0% to 25% and were within 5% for 26 of the 50 subjects (52%), and within 10% for 41 of the 50 subjects (82%). The mean difference between the two measures was 1.5% (P =.17). Test-retest reliability was high for both the HFD total score (r = 0.95) and the HFD fat subscore (r = 0.85; P <.01). CONCLUSIONS The HFD is an inexpensive, valid, and reliable clinical instrument for assessing dietary fat. It can be a viable alternative to other time-consuming methods, including computerized analysis.

Plasma Volume Changes With an Acute Bout of High-Intensity Exercise in Men With Chronic Congestive Heart Failure Secondary to Coronary Artery Disease

We assessed plasma volume changes at peak exercise in 17 nonedematous men with chronic congestive heart failure due to coronary artery disease. Our findings suggest that acute exercise is associated with transient decreases in plasma and blood volume in these patients, similar in magnitude to those reported for healthy adults at peak exercise.

Neuroendocrine Activation in Heart Failure is Modified by Endurance Exercise Training

OBJECTIVES The purpose of this study was to determine whether endurance exercise training could buffer neuroendocrine activity in chronic heart failure patients. BACKGROUND Neuroendocrine activation is associated with poor long-term prognosis in heart failure. There is growing consensus that exercise may be beneficial by altering the clinical course of heart failure, but the mechanisms responsible for exercise-induced benefits are unclear. METHODS Nineteen heart failure patients (ischemic disease; New York Heart Association [NYHA] class II or III) were randomly assigned to either a training group or to a control group. Exercise training consisted of supervised walking three times a week for 16 weeks at 40% to 70% of peak oxygen uptake. Medications were unchanged. Neurohormones were measured at study entry and after 16 weeks. RESULTS The training group (n = 10; age = 61 +/- 6 years; EF = 30 +/- 6%) and control group (n = 9; age = 62 +/- 7 years; EF = 29 +/- 7%) did not differ in clinical findings at study entry. Resting levels of angiotensin II, aldosterone, vasopressin and atrial natriuretic peptide in the training and control groups did not differ at study entry (5.6 +/- 1.3 pg/ml; 158 +/- 38 pg/ml; 6.1 +/- 2.0 pg/ml; 37 +/- 8 pg/ml training group vs. 4.8 +/- 1.2; 146 +/- 23; 4.9 +/- 1.1; 35 +/- 10 control group). Peak exercise levels of angiotensin II, aldosterone, vasopressin and atrial natriuretic peptide in the exercise and control groups did not differ at study entry. After 16 weeks, rest and peak exercise hormone levels were unchanged in control patients. Peak exercise neurohormone levels were unchanged in the training group, but resting levels were significantly (p < 0.001) reduced (angiotensin -26%; aldosterone -32%; vasopressin -30%; atrial natriuretic peptide -27%). CONCLUSIONS Our data indicate that 16 weeks of endurance exercise training modified resting neuroendocrine hyperactivity in heart failure patients. Reduction in circulating neurohormones may have a beneficial impact on long-term prognosis.