Effects of low volume resistance and cardiovascular training on strength and aerobic capacity in unfit men and women: a demonstration of a threshold model.

A threshold model postulates that prescriptively applying the appropriate cardiorespiratory and strength stimulus at a designated threshold of intensity for a brief time results in the targeted adaptations. A randomized control group design was used with 17 unfit males and females (mean age = 37.1 +/- 6.5 year) assigned to an exercise group (n = 9) who performed a progressive cardiovascular graded exercise protocol and resistance training twice a week for 12 weeks or a nonexercising control group (n = 8). The intervention included a graded exercise protocol involving a 3-min warm-up, exercising 3-4 min at 70-80% of maximum heart rate, and a 3-min cooldown. Progressive resistance exercise consisted of one set of six repetitions on each of six resistance machines. Results showed that the exercise group increased predicted aerobic capacity by 13.4% (p < 0.05), decreased submaximal rate pressure product by 17.2% (p < 0.05), and increased strength by 34% (p < 0.01). The results support a threshold model and show that time for effective exercise can be substantially reduced.