They're both effective resistance training methods, and each can be used safely and effectively depending on your ability and goals — not your sex. (nicktumminello.com)
Circuit training is a unique resistance training method in which single sets of several different exercises (usually 10 to 12) are completed in succession, with little or no rest between exercises. (bodybuilding-wizard.com)
To train his upper body, Nadal uses mostly resistance training methods and cable machines. (gymjunkies.com)