[The Physician and Sportsmedicine]

[EXERCISE ADVISER]

Cross-Training: Giving Yourself a Whole-Body Workout

Bryant Stamford, PhD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 24 - NO. 9 - SEPTEMBER 96

If your browser supports tables click here.

Exercise can provide a total-body tune-up. It can strengthen the heart, bones, muscles, and joints. It can enhance cardiovascular (heart-related) fitness, build muscle, reduce body fat, and aid in flexibility. But to see all these gains, cross-training may be needed.

In cross-training, two or more types of exercise are performed in one workout or used alternately in successive workouts. A distance runner in training, for example, may also lift weights twice a week, perform daily stretching exercises, and do high-intensity bicycle sprints every Tuesday.

Exercisers turn to cross-training to fight boredom, but also because no single exercise can yield all the potential benefits of exercise outlined above. Jogging, for example, enhances aerobic fitness (which improves cardiovascular health and requires sustained use of large-muscle groups like those in the legs). But jogging contributes little to developing muscle mass, especially in the upper body. Weight training increases muscle mass, but it does not promote flexibility.

Although cross-training seems to make perfect sense, not all experts agree on its benefits. Cross-training contradicts the time-honored principle that training should be limited in scope and closely aligned to the performance you want to improve. This is known as task specificity, and it means that if you want to be a good distance runner, you need to run mainly long distances. According to this principle, nonspecific activities for runners, like weight training or swimming laps, are a waste of effort because they do not make one a better runner.

Many sports scientists, however, believe that cross-training may lead to optimal effort, because peak performance in any physical activity usually involves more than one physical attribute. A marathoner, for example, may need a strong sprint to the finish line, and hence high levels of aerobic and anaerobic fitness (the ability to perform intense bursts of activity). Also, weight training can help reduce upper-body muscle fatigue while running. Because little overlap exists among attributes like aerobic fitness, anaerobic fitness, and strength, cross-training is required.

The Cross-Training Edge

Cross-training offers advantages for both competitive athletes and those who train simply to keep in shape and manage their weight. Cross-training helps you:

  • Add variety to your workouts to keep you interested. You can use traditional training methods like running and swimming as well as exercise on various machines or on in-line skates.
  • Develop your entire body, rather than specific parts or energy systems (aerobic vs anaerobic).
  • Distribute the load of training among various body parts, thus reducing the risk of injury.
  • Keep training while you are injured. When one body part is injured, you can train using different muscles and joints.

Planning Your Program

A cross-training program usually involves a combination of different exercises, each performed for a specific period. The exercises can all be aerobic, for example, but they usually include other types (table 1).

________________________________________________________________
Table 1. Types of Exercises for Cross-Training Programs
________________________________________________________________
Exercise Goal           Examples
Aerobic fitness*        Walking briskly, walking with hand or leg
                        weights, power walking, race walking,
                        jogging, running, swimming, water walking
                        or running, water exercises, bicycling,
                        cross-country skiing, rowing, roller 
                        skating, in-line skating, ice skating
Anaerobic fitness**     Sprinting in any of the above exercises
Muscle strength         Weight training (free weights or machines),
                        isometrics***
Muscle endurance        Low-resistance high-repetition weight 
                        training, push-ups, sit-ups, pull-ups, 
                        other calisthenics
Flexibility             Stretching, yoga
________________________________________________________________
*Aerobic exercise involves rhythmic movement of large-muscle 
groups for extended periods.
**Anaerobic exercise entails intense bursts of muscle activity.
***Isometric exercise involves contracting the muscles against 
a fixed resistance without moving the joints, as in pushing 
against a wall.
________________________________________________________________

To improve aerobic fitness, for example, you can bike for 30 minutes. To increase strength, you can lift weights for 30 minutes. You can do one form of exercise each day, or both on the same day. If you do both on the same day, you can change the order in which you do them.

Cross-training also can include diverse exercises in a single routine to promote aerobic fitness, strength, and muscle endurance. For example, in circuit training you do high-repetition, low-resistance weight training and move quickly to the next exercise. Another example is step aerobics using light dumbbells.

You can easily tailor cross-training to your needs and interests. Just select exercises from each of the types in table 1--but you don't have to limit yourself to the activities listed. Then build a program, as in "A Cross-Training Sampler," below. If you are a competitive athlete, talk to an experienced coach when making up your workout schedule.


A Cross-Training Sampler

Here is a cross-training program for all-around conditioning. It can help boost aerobic fitness, muscle strength, muscle endurance, and flexibility, and also assist in weight control by helping you burn a fair number of calories each day.

________________________________________________________________
Day of the 
Week           Activity                               Minutes
________________________________________________________________
Monday         Brisk walking with hand weights        20-30
               Stretching                             5-10
               Upper-body weight training             30
Tuesday        Jogging at a steady pace               20-30
               Stretching                             5-10
               Lower-body weight training             30
Wednesday      Swimming                               20-30
               Yoga                                   20-30
Thursday       Bicycling, rowing, or cross-country    20-30
                 skiing*                
               Stretching                             5-10
Friday         Brisk walking                          20
               Upper- and lower-body weight training  20-30
                 or circuit weight training**  
Saturday       Jogging at a varied pace               30-45
               Stretching                             5-10
Sunday***      Walking comfortably                    30-45
               Yoga                                   20-30
________________________________________________________________
*Actual activity or machine simulator.
**High-repetition, low-resistance weight training with little 
rest between exercises.
***Can be a complete rest day.
________________________________________________________________

Remember: This information is not intended as a substitute for medical treatment. Before starting an exercise program, consult a physician.

Dr Stamford is director of the Health Promotion and Wellness Center and professor of exercise physiology in the School of Education at the University of Louisville, Kentucky. He is also an editorial board member of The Physician and Sportsmedicine.


RETURN TO PERSONAL HEALTH INDEX

RETURN TO SEPTEMBER 1996 TABLE OF CONTENTS

HOME | MAP | JOURNAL | PERSONAL HEALTH | CME | RESOURCE CENTER | CALENDAR | ABOUT US

[McGraw-Hill Logo]
Copyright (C) 1996. The McGraw-Hill Companies. All Rights Reserved