Working out with a qualified trainer builds more muscle than exercising solo, a UCLA/Equinox study found. Guys who did 12 weeks of supervised resistance training gained 23% and 13% more chest-and leg-press strength, respectively, than lone lifters, and upped their VO2 max 7% more. “Unless you train in a systematic way and can self-motivate, it’s harder to get as good a result as with a coach,” says study VIP Thomas Storer, Ph.D.

Source: Journal of Strength and Conditioning Research

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