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Practical Approaches to Initiating Resistance Training in Cardiac

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					Practical Approaches to Initiating Resistance Training in Cardiac
Rehabilitation
Neil McCartney, Ph.D. Professor, Kinesiology and Medicine, McMaster
University, Program Director, McMaster Cardiac Rehabilitation Program

Resistance training can be defined as any technique that uses progressive resistance to increase
muscular strength. Using this definition the practitioner can design programs which utilize body mass
and body segments as the resistance, elastic bands, springs, free-weights or an assortment of
machines. Which method to use will depend on many practical considerations such as financial and
physical resources and staffing. This article will provide some practical guidelines for incorporating
resistance training in any cardiac rehabilitation program.
Eligibility
Recent guidelines from the American Heart Association (1) state that "contraindications to resistance
training include unstable angina, uncontrolled hypertension (systolic BP ³ 160 mmHg and/or diastolic
BP ³ 100 mmHg), uncontrolled dysrhythmias, a recent history of congestive heart failure that has not
been evaluated and effectively treated, severe stenotic or regurgitant valvular disease, and
hypertrophic cardiomyopathy". Preferred inclusion criteria are moderate to good LV function and an
exercise capacity of > 5 METS (1). If we adopt these suggestions, the vast majority of patients
enrolled in traditional community-based cardiac rehabilitation programs will be suitable candidates for
resistance training.

When to Start
Low-intensity resistance training using wall pulleys, light hand weights and elastic bands such as
Therabands, can be prescribed within 2 to 3 weeks after MI (2). CABG patients should avoid
exercises that pull on the sternum for 3 months post-sternotomy and then the stability of the sternum
should be confirmed before initiating a resistance training program. Wrist weights and 1 to 2 lb.
dumbbells are useful to begin with. Patients can do a program featuring one set of 8 to 10 exercises,
1 to 3 days each week. Each set should be 10 to 15 repetitions done to moderate fatigue. Rest
intervals are best dictated by the fatigue level and/or symptoms experienced by the patient, rather
than being set by the program staff. Increments of 1 to 3 pounds, or stronger elastic bands, can be
introduced on a weekly basis as tolerated. Regular lifting with barbells and/or weight machines can
be safely introduced 6 weeks after the acute event (1).

Resistance Training Prescription
The general principles of resistance training are similar for all groups, but participant goals, age and
what chronic diseases are present affect their application. Compared with young, healthy individuals,
cardiac patients should begin at a lower resistance and progress more gradually. Patients with joint
pain and poor range of motion can still do resistance training if machines are double pinned, or by
using variable resistance machines.

The first introduction to resistance training should establish initial training loads and emphasize the
importance of proper lifting techniques, the range of motion required for each exercise and correct
breathing. It is recommended that each repetition should include a 2 second lifting phase followed by
4 seconds of lowering, one full inspiration and exhalation and no prolonged breath holding (1).
Evidence suggests that testing the 1 RM (heaviest weight that can be lifted once through a complete
range of motion with correct form) is not deleterious to the patient (3) and can be used to determine a
precise starting weight. If this technique is adopted, patients should begin training with loads
equivalent to 30-40% of the 1 RM for upper body exercises and 50-60% of 1 RM for the lower limbs.
Maximal testing is not essential for resistance training prescription. Patients can begin training with a
light weight (or other resistance) and once they can comfortably lift the weight for 10-15 repetitions it
can be increased gradually; increments of 2-5 lb./week for arms and 5-10 lb./week for legs are quite
suitable.

Research suggests that 75% of the strength gains which occur with a 3-day/week resistance training
program can be achieved with a 2-day/week regimen, and a single-set of lifting is as effective as
multiple sets (4). Thus, a resistance training program should be done twice/week, and include one set
of 10-15 repetitions of 8-10 exercises (time required is 20 to 30 minutes.). A well-designed program
will include exercises for the major muscle groups, e.g. biceps curl, triceps extension, lat pull down,
abdominal curl, lumbar extension, bench press, shoulder press, knee extension, leg press, leg curls.
Depending on facilities, such a program can be done using dumbbells and barbells or machine
weights. Either can be effective, but the major advantage of machines is that they may be safer for
older adults who can have co-morbidities such as arthritis, poor balance and vision, which can lead to
dropping of weights.

Women and Resistance Training
Some female patients may initially be opposed to resistance training because they believe it will
make them "bulk up" or it is not "lady-like". These fears can be allayed by program staff, who should
stress that rather than getting larger the patient may experience toning and firming which will improve
their female shape. Moreover, pointing out that the increase in basal metabolic rate associated with
resistance training (5) makes it a good additional strategy for weight control can influence pre-
conceptions.

Monitoring
Obtaining a diagnostic quality ECG during resistance exercises which require "fixing" of the thorax (all
upper body, and during strong efforts with the lower limbs) is extremely challenging, due to inference
by chest muscle EMG activity. Moreover, as research evidence suggests that resistance training
provokes fewer ECG abnormalities, and signs and symptoms of ischemia than aerobic training (3),
ECG monitoring is not essential. The measurement of blood pressure can be useful, but is only valid
if the recordings are taken during the actual lifting, from a non-engaged limb. Measurements after
lifting are not representative of the pressure during the maneuver, and may even be below resting
levels (6).

Cautions
The most common cause of musculoskeletal injury during resistance training is a previous injury, so a
history should be provided by the patient and used in determining the prescription. It should be
remembered that the likelihood of injury increases with the lifting of heavy weights, so cardiac
patients should use moderate weights and gradual progression. As with aerobic exercise, program
staff need to be wary of patients who increase their own training loads without consultation, as the
increments are often overly ambitious and can provoke problems.


References

           Pollock M.L., et al. Resistance exercise in individuals with and without
           cardiovascular disease. Circulation 101:828-833, 2000.

           American Association of Cardiovascular and Pulmonary Rehabilitation. Guidelines for Cardiac Rehabilitation and
           Secondary Prevention Programs. 3rd Edition, Champaign, Ill: Human Kinetics, 1999.

           McCartney N. Role of resistance training in heart disease. Med. Sci. Sports Exerc. 30: (Suppl.) S396-S402, 1998.

           Feigenbaum M.S. and Pollock M.L. Strength training: rationale for current guidelines for adult fitness programs.
           Physician Sports Med. 25:44-64, 1997.

           Pratley R. et al. Strength training increases resting metabolic rate and norepinephrine levels in healthy 50- to 65-yr
           old men. J. Appl. Physiol. 76:133-137, 1994.

           Wiecek E.M., McCartney N. and McKelvie R.S. Comparison of direct and indirect measures of systemic arterial
           pressure during weightlifting in coronary artery disease. Am. J. Cardiol. 66:1065-1069, 1990.

				
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