In a six-week study of intermediate exercisers,13 we examined the effects of slow positive emphasis training (10 seconds lifting, four seconds lowering) and slow negative emphasis training (four seconds lifting, 10 seconds lowering). As presented in Figure 2, both of these slow training techniques produced significant strength gains (22 pounds and 26 pounds, respectively) in the previously plateaued participants.

Extended sets. Extended sets increase the training stimulus by tiring more muscle fibers. For example, performing three sets of leg extensions with 100 pounds fatigues the same muscle fibers three times. However, performing one set of leg extensions with 100 pounds, then immediately completing a few post-fatigue repetitions with 85 pounds, involves additional muscle fibers. This high-intensity technique is known as breakdown training, and it effectively increases the strength-building stimulus.

In an eight-week study of beginning exercisers,14 we compared breakdown training with standard training. As shown in Figure 3, the breakdown training group recorded a 25-pound strength gain and the standard training group recorded an 18-pound strength gain.

A similar advanced exercise procedure known as assisted training requires an instructor to manually assist with the lifting phase of a few post-fatigue repetitions. Because muscles produce more force during negative contractions than during positive contractions, the instructor does not assist with the lowering phase of post-fatigue repetitions. We recently compared assisted training and standard training with beginning exercisers. After eight weeks, the assisted training subjects increased their strength by 29 pounds and the standard training subjects increased their strength by 20 pounds (see Figure 4).

We also examined the effects of breakdown training and assisted training with intermediate exercisers.15 As presented in Figure 5, both of these extended set procedures produced significant strength gains (15 pounds and 17 pounds, respectively) over the six-week training period.

Actually, the presence of an instructor may have a significant impact on strength development. In two of the studies,13,15 the participants performed two exercises (low-back and abdominal machines) in the standard manner. Although they did not use any advanced training in these exercises, their previously plateaued weight loads increased 12 pounds in six weeks, indicating that just being observed by an instructor can enhance the training effect. Apparently, people use better exercise form and give greater training effort when an instructor is watching.

While it is satisfying to see strength gains, many intermediate trainers want more muscle as well. As shown in Figure 6, subjects who used a combination of high-intensity techniques added almost three pounds of muscle during the six-week training period.16 They also lost more than three pounds of fat for an impressive improvement in body composition.

Summary

Bodybuilders, weightlifters and athletes who strength train for competitive purposes typically perform multiple exercise sets to achieve their performance objectives. This high-volume training approach works well, especially for those with genetic potential for large muscles. However, the average fitness enthusiast who desires greater strength development may have a difficult time factor. Many adults are limited to relatively brief exercise sessions and, therefore, require a more time-efficient training approach. High-intensity training provides a productive alternative to multiple exercise sets.

REFERENCES

1. Westcott, W. A physical evolution: Sedentary adults see marked improvements in as little as two days a week. IDEA Today, 1996; 14: 9, 58-65.

2. Campbell, W., M. Crim, V. Young & W. Evans. Increased energy requirements and changes in body composition with resistance training in older adults. American Journal of Clinical Nutrition, 1994; 60: 167-175.

3. Menkes, A., S. Mazel, A. Redmond, et al. Strength training increases regional bone mineral density and bone remodeling in middle-aged and older men. Journal of Applied Physiology, 1993; 74: 2478-2484.

4. Hurley, B. Does strength training improve health status? Strength and Conditioning Journal, 1994; 16: 7-13.

5. Koffler, K., A. Menkes, A. Redmond, et al. Strength training accelerates gastrointestinal transit in middle-aged and older men. Medicine and Science in Sports and Exercise, 1992; 24: 415-419.

6. Harris, K., & R. Holly. Physiological response to circuit weight training in borderline hypertensive subjects. Medicine and Science in Sports and Exercise, 1987; 19: 246-252.

7. Hurley, B., J. Hagberg, A. Goldberg, et al. Resistance training can reduce coronary risk factors without altering V02 max or percent body fat. Medicine and Science in Sports and Exercise, 1988; 20: 150-154.

8. Risch, S., N. Nowell, M. Pollock, et al. Lumbar strengthening in chronic low back pain patients. Spine, 1993; 18: 232-238.

9. Tufts University Diet and Nutrition Letter. Never too late to build up your muscle. 1994; 12: 6-7 (September).

10. American College of Sports Medicine. The recommended quality and quantity of exercise for developing and maintaining cardiovascular and muscular fitness in healthy adults. Medicine and Science in Sports and Exercise, 1990; 22: 265-274.

11. Kraemer, W. Everything you wanted to know about strength training but were afraid to ask. General Session, IDEA Personal Trainer Conference, Anaheim, CA, March 23.

12. Westcott, W. Exercise speed and strength development. American Fitness Quarterly, 1994; 13 (3): 20-21.

13. Westcott, W. High intensity strength training. IDEA Personal Trainer, 1995; 6 (7): 9.

14. Westcott, W. High-intensity strength training. Nautilus, 1994; 4 (1): 5-8.

15. Westcott, W. Make your method count. Nautilus,1996; 5 (2): 3-5.

16. Westcott, W. Research on advanced strength training. American Fitness Quarterly, 1996; in press.

Figure 1. Average increase in exercise weight loads after eight weeks of standard or slow positive emphasis training with

beginner level subjects (N=152)

Figure 2. Average increase in exercise weight loads after six weeks of slow positive emphasis or slow negative emphasis

training with intermediate level subjects (N=15)

Figure 3. Average increase in exercise weight loads after eight weeks of standard or breakdown training with beginner

level subjects (N=45).

Figure 4. Average increase in exercise weight loads after eight weeks of standard or assisted training with beginner level subjects

(N=42)

Figure 5. Average increase in exercise weight loads after six weeks of breakdown or assisted training with intermediate

level subjects (N=7)

Figure 6. Average changes in exercise weight loads and body composition for six-week studies involving high-intensity training techniques with intermediate level subjects (N=35).

By Wayne L. Westcott, Ph.D. A fitness research advisor at the South Shore YMCA in Quincy, Mass., and author of 21 books on strength training.