The purpose of this study is to compare the Equinox Personal Coaching exercise training method to self-directed exercise training in helping subjects become more fit. Men between 30 and 44 years of age who exercise on a regular basis and are interested in receiving Equinox personal training will be invited to participate. The investigators will enroll 36 subjects at University of California, Los Angeles (UCLA), the only site. The hypothesis of this study is that subjects randomized to the Personal Coaching Method will result in significantly greater lean mass accrual than those randomized to self-directed training over the 12 weeks of the study.

Subjects will have 2 Baseline visits over 1 week, then be randomized to receive either Coached training or self-training, which they will do for 12 weeks, then complete two End of Study visits over the final week. Visits 1 and 3 include questionnaires, skinfold fat/lean body mass measurements, and strength and aerobic performance tests, and will take place at Equinox. Visits 2 and 4 include a DEXA scan and ECG, which will take place at UCLA.

Inclusion Criteria:

• Men aged 30-44 years
• Body mass index less than 30 kg/m2.
• Currently exercising with or without coaching more than 4 days but less than 8 days per month for the past three months (Equinox Motivated or Super Motivated categories);
• Willing to commit to 12 weeks of thrice weekly training at the Century City Equinox club with or without an Equinox coach.

Exclusion Criteria:

• Over age 44
• Musculoskeletal conditions limiting participation
• Unstable cardiovascular, pulmonary, metabolic, or other disorders that would preclude high intensity exercise training.
• Abnormal ECG at Screening that indicates the subject is not healthy enough for maximal exercise in the opinion of the principal investigator
• Family history of sudden death associated with exercise, based on self-report