SPECIAL COMMUNICATIONS: Letters to the Editor-in-Chief
The focus of Marzolini et al. (4) on resistance training as a treatment of coronary disease is commendable. However, several points reflected in their data and discussion need clarification and suggest different research directions.
A study contrasting outcomes between single and multiple sets needs to be presented within the context of many such studies in the last several decades. The collective outcomes and analyses of published evidence suggesting that multiple sets produce superior strength outcomes continue to be questioned. Such is the case in the present study. There were no differences in strength or local muscle endurance between the one-set group or three-set group. Whereas the three-set group showed small but greater lean body mass gains than the one-set group, the one-set group showed small but greater body fat loss. It is not clear which body composition outcome is more desirable. The three-set group, but not the one-set group, increased ventilatory anaerobic threshold (VAT). However, contrary to the statement in the discussion section, there were no significant differences in V˙O2peak or local muscular endurance between the two groups. Thus, the health value of a threefold increase in resistance training volume is uncertain.
The results for the group performing only aerobic training also require clarification. This group walked or jogged 262 km, spending approximately 100 h in their training. Yet, the gain in V˙O2peak was only 0.57 METs. This group experienced no significant gains in VAT, strength, local muscular endurance, or body composition. In the methods section, the aerobics training prescription was defined as working toward 1 h per session at 80% V˙O2peak. Their data indicated that this group trained at a mean of 73.1% of maximum heart rate achieved at baseline, considerably less than the target. Perhaps the protocol was not progressive enough, or participants were not able and/or motivated to train at the prescribed intensity for a long duration. The minimal outcomes and likely health benefits from 100 h of conventional, lower- to moderate-intensity long-duration aerobic training alone, however, call into question its utility. A recent RCT also showed that training at only 50% of V˙O2peak for approximately 64 min per session, three times per week, resulted in a gain of less than 0.5 METs and minimal impacts on other coronary disease risk factors (1). Indeed, there is a dose-response relationship between intensity of training and increases in aerobic capacity (2).
The results for the group aerobic training only also are considerably less than the outcomes produced by interval training performed with a similar group of patients with CHD (5). However, rather than repeated intervals and higher volume associated with a high-intensity interval training, recent data showed that a lower-volume graded exercise protocol (GXP) progressively performed two times per week appreciably increased aerobic capacity (3). The GXP has a several-minute graded warm-up, one several to 5-min work segment of moderate to high intensity, and a several-minute graded cool-down.
Clarification of these points can enhance subsequent research. Replicating the one-set and three-set protocols and assessing the impacts of resistance training alone and other forms of aerobic training are critical for the treatment of coronary disease.
Richard A. Winett, PhD
Department of Psychology
Center for Research in Health Behavior
1. Church TS, Earnest C, Skinner JS, Blair SN. Effects of different doses of physical activity on cardiorespiratory fitness among sedentary overweight or obese postmenopausal women with elevated blood pressure. JAMA
2. Gormley SE, Swain DP, High R, et al. Effect of intensity of aerobic training on V˙O2max
. Med Sci Sports Exerc
3. Lutes LD, Winett RA, Barger SD, Wojcik JR, Nickols-Richardson SM, Anderson SE. Small changes in nutrition and physical activity promote weight loss and maintenance: 3-month evidence. Ann Behav Med
4. Marzolini S, Oh PI, Thomas SG, Goodman JM. Aerobic and resistance training in coronary disease: Single versus multiple sets. Med Sci Sports Exerc
5. Wisloff U, Stoylen A, Loennechen JO, et al. A superior cardiovascular effect of aerobic interval training versus moderate continuous training in heart failure patients. Circulation